USRE48534E1 - Detachable dilator blade - Google Patents

Abstract

A tissue retraction system includes a dilator and a first retractor member and a retraction assembly. The dilator is configured to be inserted into a tissue body and also includes at least one engagement member. The first retractor member includes a body and at least one engagement member that is configured to attach to the at least one engagement member of the dilator so as to removably attach the retractor member to the dilator body. The retraction assembly includes a retractor body and at least a second retractor member that is movably supported by the retractor body. The retractor body is configured to be attached to the first retractor member. The tissue protection system may also include a neuromonitoring member configured to determine a characteristics of the tissue.

Description

RELATED APPLICATIONS

This application is a broadening reissue of U.S. Pat. No. 9,265,490, which issued from U.S. patent application Ser. No. 13/447,931 filed on Apr. 16, 2012.

FIELD OF DISCLOSURE

The present disclosure generally relates to apparatus, systems, and methods for performing minimally invasive surgery, and more particularly, to dilator assemblies, retractors, systems, and methods for accessing a surgical site to conduct a surgical procedure.

BACKGROUND

In some surgical procedures, surgeons employ open surgery or minimally invasive techniques to access a target site within the patient's body. Open surgery techniques typically require large incisions and high amounts of tissue displacement to gain access to the surgical target site. Due to the large incisions and high amounts of tissue displacement, patients who undergo open surgery usually require a relatively long recovery time. Minimally invasive techniques, in contrast, involve significantly smaller incisions and require less tissue displacement. As a consequence, patients who undergo minimally invasive procedure have significantly shorter recovery time than patients who undergo open surgery.

In view of the advantages of minimally invasive procedures over open surgery, surgical access systems have been developed to access a surgical target site using a minimally invasive approach. For example, surgical dilators, retractors, and systems typically displace or retract tissue to establish an operative corridor to a surgical target site. Surgeons have employed known surgical access retractors and systems in different kinds of surgeries. In spinal surgeries, for example, spinal access systems can be used to retract tissue in order to perform posterior lumbar interbody fusion (PLIF), anterior lumber interbody fusion (ALIF), or any other suitable spinal approach and surgery. A surgical target site can also be accessed via antero-lateral access, postero-lateral access, and direct-lateral access.

SUMMARY

The present disclosure relates to tissue retraction systems configured to dilate a tissue body. In one embodiment, the tissue retraction system generally includes a dilator and a first retractor member. The dilator is configured to be inserted into the tissue body toward a surgical site, and includes a dilator body that is elongate along a longitudinal direction and sized to dilate the tissue body. Furthermore, the dilator includes at least one engagement member. The first retractor member includes a body and at least one engagement member that is configured to attach to the at least one engagement member of the dilator so as to removably attach the retractor member to the dilator body. The first retractor member and the dilator cooperate so as to define a passageway when the first retractor member is attached to the dilator body. The tissue retraction system further includes a retractor assembly. The retraction assembly includes a retractor body and at least a second retractor member that is movably supported by the retractor body. The retractor body is configured to be attached to the first retractor member.

The present disclosure also relates to methods of accessing a surgical site. In an embodiment, the method includes the following steps: inserting a dilator assembly into a tissue body, the dilator assembly comprising a dilator and a retractor member removably attached to the dilator; advancing the dilator assembly toward the surgical site to dilate at least a portion of the tissue body; removing the dilator from the tissue body while leaving the retractor member in the tissue body; and attaching a retractor assembly to the retractor member disposed in the tissue body.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of a preferred embodiment, are better understood when read in conjunction with the appended diagrammatic drawings. For the purpose of illustrating the invention, the drawings show an embodiment that is presently preferred. The invention is not limited, however, to the specific instrumentalities disclosed in the drawings. In the drawings:

FIG. 1A is a perspective view of a dilator assembly constructed in accordance with an embodiment of the present disclosure, including a dilator and a retractor member removably attached to the dilator, showing the dilator assembly disposed adjacent to a spinal column;

FIG. 1B is a perspective view of the dilator assembly shown inFIG. 1;

FIG. 2A is a perspective view of a retractor assembly in accordance with an embodiment of the present disclosure, including a retractor body and a plurality of retractor members extending from the body, wherein the plurality of retractor member includes the retractor member illustrated inFIG. 1 attached to the retractor body, showing the retractor assembly in a first or contracted position and disposed adjacent to the spinal column;

FIG. 2B is a perspective view of the retractor assembly illustrated inFIG. 2A, shown in a second or expanded position whereby the retractor members are spaced apart further than when the retractor assembly is in the contracted position;

FIG. 3A is a top view of the dilator assembly shown inFIG. 1, showing the retractor member attached to the dilator;

FIG. 3B is an enlarged top view of a first end of the dilator assembly shown inFIG. 3A, taken atregion3B;

FIG. 3C is an enlarged top view of another portion of the dilator assembly shown inFIG. 3, taken at region3A;

FIG. 4A is a perspective view of the retractor member shown inFIG. 1;

FIG. 4B is a side elevation view of the retractor member shown inFIG. 4A;

FIG. 4C is a front elevation view of the retractor member shown inFIG. 4A;

FIG. 4D is a rear elevation view of the retractor member shown inFIG. 4A;

FIG. 4E is a top plan view of the retractor member shown inFIG. 4A;

FIG. 4F is a bottom plan view of the retractor member shown inFIG. 4A;

FIG. 5 is a perspective view of the retractor assembly shown inFIG. 2A;

FIG. 6A is a perspective view of a portion of the retractor body shown inFIG. 5;

FIG. 6B is a top plan view of the portion of the retractor body shown inFIG. 6A, attached to the retractor member shown inFIG. 1;

FIG. 6C is a perspective view of the portion of the retractor body and the retractor member shown inFIG. 6B;

FIG. 6D is a side elevation view of the portion of the retractor body and the retractor member shown inFIG. 6B;

FIG. 7 is a cross-sectional side view of the portion of the retractor body and the retractor member similar toFIG. 6B, but showing the retractor member connected to the retractor body in accordance with an alternative embodiment;

FIG. 8 is a cross-sectional side view of the portion of the retractor body and the retractor member similar toFIG. 6B, but showing the retractor member connected to the retractor body in accordance with an alternative embodiment;

FIG. 9A is a top view of a first dilator and an obturator disposed in the surgical site;

FIG. 9B is a perspective view of a perspective view of the first dilator and the obturator disposed in the surgical site;

FIG. 10A is a top view of the dilator assembly shown inFIG. 1A disposed over the first dilator and the obturator;

FIG. 10B is a perspective view of the dilator assembly shown inFIG. 1A disposed over the first dilator and the obturator;

FIG. 11A is a top view of the retractor member shown inFIG. 4A disposed adjacent the surgical site;

FIG. 11B is a perspective view of the retractor member shown inFIG. 4A disposed adjacent the surgical site;

FIG. 12A is a perspective view the retractor assembly shown inFIG. 2A being advanced toward the retractor member shown inFIG. 4A;

FIG. 12B is a perspective view of the retractor member shown inFIG. 4A attached to the retractor assembly shown inFIG. 2A;

FIG. 13A is a perspective view of the retractor assembly shown inFIG. 2A being advanced along the dilator assembly shown inFIG. 1A;

FIG. 13B is a perspective view of the refractor assembly shown inFIG. 2A being connected to the retractor member shown inFIG. 4A;

FIG. 14A is a perspective view of the retractor assembly shown inFIG. 2A partially disposed in the tissue body, and the dilators being removed from the tissue body;

FIG. 14B is a perspective view of the refractor assembly shown inFIG. 2A after the dilators have been removed from the tissue body;

FIG. 15A is a perspective view of a dilator assembly constructed in accordance with an embodiment of the present disclosure, including a Kirschner wire, a first dilator, a second dilator, and a neuromonitoring device, showing the dilator assembly disposed adjacent to a spinal column;

FIG. 15B is a perspective view of the retractor assembly shown inFIG. 2A connected to a portion of the dilator assembly ofFIG. 15A;

FIG. 16A is a perspective exploded view of a portion of the dilator assembly shown inFIG. 15A;

FIG. 16B is a side elevation view of the dilator assembly shown inFIG. 16A connected to each other;

FIG. 16C is a top cross-sectional view of the dilator assembly shown inFIG. 16A, taken acrosssection line16C-16C;

FIG. 16D is a top cross-sectional view of the dilator assembly shown inFIG. 16A, taken acrosssection line16D-16D;

FIG. 17A is an exploded view of the wire, the first dilator, and the second dilator shown inFIG. 15A;

FIG. 17B is a top cross-sectional view of the second dilator shown inFIG. 17A, taken alongsection line17B-17B;

FIG. 17C is a top cross-sectional view of the first dilator shown inFIG. 17A, taken alongsection line17C-17C;

FIG. 18A is a perspective view of a partial retractor member coupled to the dilator and a neuromonitoring member;

FIG. 18B is a side elevation view of the partial retractor member coupled to the dilator and the neuromonitoring member;

FIG. 18C is a cross-sectional view of the partial retractor member coupled to the dilator and the neuromonitoring member, taken alongsection line18C-18C ofFIG. 18B;

FIG. 18D is a cross-sectional view of the partial retractor member coupled to the dilator and the neuromonitoring member, taken alongsection line18D-18D ofFIG. 18B;

FIG. 18E is a cross-sectional view of the partial retractor member coupled to the dilator and the neuromonitoring member, taken alongsection line18E-18E ofFIG. 18B;

FIG. 18F is a rear perspective view of the partial retractor member shown inFIG. 18A; and

FIG. 18G is front perspective view of the partial retractor member shown inFIG. 18A

DETAILED DESCRIPTION OF THE DRAWINGS

With reference toFIG. 1A-2B, atissue retraction system98 can include adilator106, aretractor body301, and aretractor member102 that is configured to be removably attached to thedilator106 so as to define adilator assembly100 that is configured to be inserted into atissue body400 so as to at least partially define a passageway toward a desiredsurgical site402. Theretractor member102 and thedilator106 can cooperate so as to define a passageway toward thesurgical site402. Theretractor member102 can be removed from thedilator106 and attached to theretractor body301 so as to define aretractor assembly300 that is configured to be inserted into thetissue body400, for instance after thetissue body400 has been dilated by thedilator assembly100. Theretractor assembly300 can be actuated from a first contracted position to a second expanded position so as to further dilate thetissue body400. Thus, it should be appreciated that thetissue retraction system98 can be configured to dilate the tissue body, for instance from an initial position, to a first dilated position, and further to a second dilated position. Thedilator106 can dilate thetissue body400 to the first dilated position, and expansion of theretractor assembly300 can further dilate thetissue body400 from the first dilated position to the second dilated position. Thedilator106 is also referred to as the first dilator. Theretractor member102 is configured to be attached to aretractor assembly300 of the type having arefractor body301 and at least one other retractor member that is movably supported by theretractor body301, such that theretractor member102 is spaced from the other retractor member. As described in more detail below, the first dilated position can be a sequentially dilated position. Examples of retractor assemblies are described and illustrated in U.S. Pat. Ser. No. 13/237,710, filed on Sep. 20, 2011, the entire disclosure of which is incorporated by referenced herein.

Thetissue body400 at least partially includes tissue, such as anatomical tissue and a tissue substitute, and can further include an implant or the like. Anatomical tissue can include, but is not limited to, soft tissue such as skin, tendons, ligaments, fascia, fibrous tissues, fat, muscle, nerves, blood vessels, and the like. For example, thetissue body400 can include apsoas muscle406, and thesurgical site402 can include a region of thespine408, such as the lumbar region. Tissue substitutes can include soft tissue substitute, such as a graft.

Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “lower” and “upper” designate directions in the drawings to which reference is made. The words “inner” or “distal” and “outer” or “proximal” refer to directions toward and away from, respectively, the geometric center of the implant and related parts thereof. The words, “anterior”, “posterior,” “superior,” “inferior,” “medial,” “lateral,” and related words and/or phrases designate preferred positions and orientations in the human body to which reference is made and are not meant to be limiting. The terminology includes the above-listed words, derivatives thereof and words of similar import.

As illustrated inFIGS. 1A-B, thedilator assembly100 is configured to dilate thetissue body400 so as to displace portions of thetissue body400 away from other portions of thetissue body400. It should be appreciated that when theretractor member102 is attached to thedilator106, thedilator assembly100 can include thedilator106 and theretractor member102. Theretractor member102 can be configured as arefractor blade104 or any alternative suitably constructed member as desired that is configured to be removably supported by, for instance attached to, thedilator106. For instance, therefractor member102 can include, but is not limited to, theretractor blade104, an arm, a rod, a plate, or any apparatus, device, mechanism, or means capable of retracting tissue, such as thetissue body400.

At least one or both of thedilator assembly100 and theretractor assembly300 can include one or more sensors that can, for instance, the sensors can be carried by thedilator106 andretractor member102, respectively. The sensors can be configured as probes, electrodes, or the like, that are configured to detect properties or characteristics of thetissue body400. In use, the sensors can be used for electromyography (EMG), mechanomyogram (MMG), pressure sensing, and/or vibration sensing. The sensors thereby provide output to a user interface so as to provide guidance information to a user that can be used to guide thedilator106 and theretractor member102 without impinging upon nerve tissue.

During operation, thedilator assembly100 can be inserted into thetissue body400, such as thepsoas muscle406. Thedilator assembly100 can then be advanced toward thesurgical site402, such as thelumbar spine408, until at least a portion of thedilator assembly100 reaches a location adjacent to thesurgical site402. Theretractor member102 can be removed from thedilator106, and thedilator106 can be removed from thetissue body400, leaving theretractor member102 in thetissue body400. Theretractor body301 can be attached to theretractor member102, so as to retract the dilatedtissue body400 as discussed in more detail below. For instance, theretractor body301 can be attached to theretractor member102 before or after thedilator106 has been removed from thetissue body400. Thedilator106 is configured to be inserted into thetissue body400 toward asurgical site402.

With continuing reference toFIGS. 1A-B, thedilator assembly100 defines afirst assembly end144 and asecond assembly end146 that is spaced from thefirst assembly end144 along alongitudinal direction110. Thefirst assembly end144 can define a proximal end and thesecond assembly end146 can define a distal end that is spaced distally with respect to thefirst assembly end144 along a distal direction, such that thesecond assembly end146 is configured to be positioned adjacent thesurgical site402. Thedilator106 includes, but is not limited to, a dissector, an obturator, a sheath, a sleeve, a trocar, a cannula, a tube, a partial tube, a surgical port, or any device, apparatus, mechanism, or suitable apparatus capable of dilating tissue, such as thetissue body400. Thedilator106 and theretractor member102 can be at least partly made from any suitable substantially rigid material, such as suitable metallic and polymeric materials. Suitable metallic materials include, but are not limited to, stainless steel, titanium, aluminum, and alloys thereof. Suitable polymeric materials include, but are not limited to, thermoplastics, such as polyetheretherketone (PEEK).

Thedilator106 includes adilator body108 that is elongate along thelongitudinal direction110 and is sized to dilate thetissue body400 as thedilator106 is inserted into thetissue body400. Thedilator body108 defines a proximal orfirst dilator end112 and a distal orsecond dilator end114. Thefirst dilator end112 and thesecond dilator end114 of thedilator body108 are spaced apart from each other along thelongitudinal direction110. Thedilator body108 further defines aninner dilator surface126, anouter dilator surface128 opposite to theinner dilator surface126, afirst dilator side130 that is connected between theinner dilator surface126 andouter dilator surface128, and asecond dilator side132 disposed between theinner dilator surface126 and theouter dilator surface128. For instance, the first and second dilator sides130 and132 can define surfaces that extend between the inner and outer dilator surfaces126 along atransverse direction120 that extends substantially perpendicular to thelongitudinal direction110. The first and second dilator sides130 and132 can be spaced from each other so as to define agap133 that is defined between the first and second dilator sides130 and132, and is elongate along thelongitudinal direction110. Thus, thedilator body108 can terminate at the first and second dilator sides130 and132. In accordance with one embodiment, the first and second dilator sides130 and132 can be spaced from each other along alateral direction121 that extends substantially perpendicular to thelongitudinal direction110 and thetransverse direction120; though it should be appreciated that the first and second dilator sides130 and132 can be spaced from each other along any suitable direction as desired.

Theouter dilator surface128 and theinner dilator surface126 can have a substantially curved shape or can define any suitable alternative shape. In accordance with the illustrated embodiment, thedilator body108 can have a substantially partial cylindrical shape. Accordingly, the cross-section of thedilator body108, taken along a direction that is substantially perpendicular to thelongitudinal direction110, can be substantially arc-shaped or substantially semicircular. It is envisioned, however, that the cross-section of thedilator body108 can have other suitable shapes. In accordance with the illustrated embodiment, the first and second dilator sides130 and132 can be spaced from each other along an angular direction greater than 180 degrees as defined by thedilator body108. Accordingly, as described in more detail below with reference toFIGS. 3A-C, theretractor member102 can include abody122 that defines opposed retractor sides148 and150 are spaced from each other along an angular direction less than 180 degrees along thebody122. Thus, thebody122 of theretractor member102 can terminate at the first and second retractor sides148 and150. The cross-sectional shape of thedilator body108 can be complementary to the cross-sectional shape of theretractor member102 so that thedilator body108 and theretractor member102 cooperate to define a substantially circular cross-section or any alternatively shaped cross-section that is defined along thetransverse direction120. It should be appreciated, however, that theretractor member102 can be shaped differently from thedilator body108 in any manner, such that theretractor member102 is removably attachable to thedilator body108, for instance so as to at least partially close thegap133. Thebody122 can define a proximal end and a distal end that is spaced from the proximal end along a longitudinal direction. Further, thebody122 can define an inner passageway-facingsurface134 and an opposed outer tissue-facingsurface136. Theshim141 can be movably coupled to the inner-passageway-facingsurface164 134 of thebody122. Theelectrode617 can be attached to the outer tissue-facingsurface136 of thebody122.

Theinner dilator surface126 defines achannel116 that can extend through thedilator body108 from thefirst dilator end112 to thesecond dilator end114 along thelongitudinal direction110. Thegap133 can be in communication with thechannel116 along thetransverse direction120 or any alternative direction that is substantially perpendicular to thelongitudinal direction110. It should be appreciated that theretractor member102 is attachable to thedilator body108 so as to close at least a portion of thegap133. As is described in more detail below, theretractor member102 can be translatably attached to thedilator body108 so as translate relative to thedilator body108, and thus thegap133, along thelongitudinal direction110. Thus, thegap133 can be referred to as a variable sized gap. As used herein, thechannel116 can include, but is not limited, to a hole, a slot, a groove, an opening, a cavity, a void, or any open space that is configured and sized to receive another dilator that can define a channel that is smaller than thechannel116, such that thedilator106 can dilate thetissue body400 beyond the dilation from the other dilator. Thus, it should be appreciated that thedilator assembly100 can include one or more dilators that have channels of different sizes that can be fitted over each other so as to sequentially dilate thetissue body400.

In accordance with the illustrated embodiment, the inner and outer dilator surfaces126 and128 extend continuously between the first and second dilator sides130 and132. Accordingly, it can be said that the first and second dilator sides130 and132 are substantially fixed to each other, such that thechannel116 has a size that is fixed. For instance, the first and second dilator sides130 and132 are not configured to move with respect to each other so as to increase the size of thechannel116 when thedilator body108 is inserted into thetissue body400. In embodiments where thedilator body108 is entirely rigid, the first and second dilator sides130 and132 are entirely fixed with respect to relative movement. In embodiments where thedilator body108 is flexible, such that thedilator body108 can be flexed in response to an applied force, the first and second dilator sides130 and132 can be referred to as substantially fixed with respect to each other, and not configured to move with respect to each other once thedilator body108 is inserted into thetissue body400. Furthermore, in accordance with the illustrated embodiment, thedilator106 can include only a singlemonolithic dilator body108.

Referring now also toFIGS. 4A-D, theretractor member102 can be configured as aretractor blade104, and includes abody122 that defines a proximal orfirst end138 and a distal orsecond refractor end140 that is spaced from thefirst end138 along alongitudinal direction111. It should be appreciated that when theretractor member102 is attached to thedilator106, thelongitudinal direction111 of theretractor member102 can be coincident with thelongitudinal direction110 of thedilator106. Theretractor member102 can further define aninner retractor surface134 and an opposedouter refractor surface136 that is spaced from theinner retractor surface134 along atransverse direction113 that extends substantially perpendicular to thelongitudinal direction111. It should thus be appreciated that when theretractor member102 is attached to thedilator106, thetransverse direction113 of theretractor member102 can be coincident with thetransverse direction120 of thedilator106.

The inner and outer retractor surfaces134 and136 can extend between the first and second ends138 and140, respectively, along thelongitudinal direction111. Theretractor member102 can further define afirst retractor side148 that is connected between theinner retractor surface134 andouter retractor surface136, and asecond retractor side150 that is connected between theinner retractor surface134 and theouter retractor surface136. For instance, the first and second retractor sides148 and150 can define surfaces that extend between the inner and outer refractor surfaces134 and136 along atransverse direction123 that extends substantially perpendicular to thelongitudinal direction111 and thelateral direction113. In accordance with one embodiment, the first and second retractor sides148 and150 can be spaced from each other along alateral direction123 that extends substantially perpendicular to thelongitudinal direction110 and thetransverse direction113; though it should be appreciated that the first and second retractor sides148 and150 can be spaced from each other along any suitable direction as desired.

At least a portion up to all of theouter retractor surface136 and theinner retractor surface134 can have a substantially curved shape along a cross-section that is substantially perpendicular to thelongitudinal direction111, or can be alternatively shaped along the cross-section as desired. The first and second refractor sides148 and150 can be spaced a distance substantially equal to a distance that the first and second dilator sides130 and132 are spaced (for instance, along thelateral direction123 and121, respectively). Accordingly, at least one or both of the first and second retractor sides148 and150 are configured to attach to the complementary one or both of the first and second dilator sides130 and132, respectively, so as to attach theretractor member102 to thedilator106 as illustrated inFIG. 1B.

Referring now toFIGS. 3A-4F, theretractor member102 can include at least one attachment member, such as a firstretractor engagement member154 and a secondretractor engagement member158 that are carried by thebody122 and are configured to removably attach to thedilator body108. Theretractor member102 can include an engagement member that is configured to attach to thedilator106 that is the same as the engagement member that is configured to attach to therefractor assembly300. The first and secondretractor engagement members154 and158 can extend out from thebody122, for instance from the first andsecond sides148 and150, respectively. In accordance with the illustrated embodiment, the first and secondretractor engagement members154 and158 are monolithic with thebody122; though it should be appreciated that the first and secondretractor engagement members154 and158 can alternatively be separate from thebody122 and attached to the body. In accordance with the illustrated embodiment, the first and secondretractor engagement members154 and158 are configured as protrusions that extend out from thebody122, for instance from the first andsecond sides148 and150 along a direction that is angularly offset, such as substantially perpendicular, from the first andsecond sides148 and150. The first and secondretractor engagement members154 and158 can be elongate along thelongitudinal direction111. In accordance with the illustrated embodiment, the first andsecond engagement members154 and158 define a first thickness along a direction that is substantially perpendicular to thelongitudinal direction111, and thebody122 defines a second thickness along the same direction that is substantially perpendicular to thelongitudinal direction111, such that the first thickness is less than the second thickness. For instance, in accordance with one embodiment, the first and secondretractor engagement members154 and158 can be referred to as tongues that extend out from the first andsecond sides148 and150, respectively. Therefractor member102 can include at least one engagement member that is carried by thebody122 and configured to attach to adilator106.

With continuing reference toFIGS. 3A-4F, thedilator106 can include at least one attachment member, such as a firstdilator engagement member156 and a seconddilator engagement member160 that are carried by thedilator body108 and are configured to attach to the complementary first and secondretractor engagement members154 and158, respectively, so as to removably and translatably attach to theretractor member102 to thedilator body108. The first and seconddilator engagement members156 and160 can be configured as recesses that extend into thedilator body108, for instance into the first and second dilator sides130 and132, respectively. The first and seconddilator engagement members156 and160 can be elongate along thelongitudinal direction110. In accordance with the illustrated embodiment, the first and seconddilator engagement members156 and160 are monolithic with thedilator body108; though it should be appreciated that the first and seconddilator engagement members154 and158 can alternatively be separate from thedilator body108 and attached to thedilator body108. In accordance with the illustrated embodiment, the first and seconddilator engagement members156 and160 are configured as recesses that extend out from thebody122, for instance from the first and second dilator sides130 and132 along a direction that is angularly offset, such as substantially perpendicular, from the first andsecond sides130 and132. In accordance with the illustrated embodiment, the first and seconddilator engagement members156 and160 define a third thickness along a direction that is substantially perpendicular to thelongitudinal direction110, and thedilator body108 defines a fourth thickness along the same direction that is substantially perpendicular to thelongitudinal direction110, such that the third thickness is less than the fourth thickness. For instance, in accordance with one embodiment, the first and seconddilator engagement members156 and160 can be referred to as grooves that are recessed into the first andsecond sides130 and132, respectively.

Thus, it should be appreciated that thedilator assembly100 can include anattachment mechanism152 that includes the at least one engagement member of theretractor member102, such as the first and secondretractor engagement members154 and158, respectively. Theattachment mechanism152 further includes the at least one engagement member of thedilator106, such as the first and seconddilator engagement members156 and160. The firstretractor engagement member154 is configured to attach to the firstdilator engagement member156 so as to translatably attach theretractor member102 to thedilator106. Similarly, the secondretractor engagement member158 is configured to translatably attach to the seconddilator engagement member160 so as to attach theretractor member102 to thedilator106. Thus, theretractor member102 is configured to translate along thedilator106, for instance along thelongitudinal direction110.

In accordance with the illustrated embodiment, the first and secondretractor engagement members154 and158 are configured to be received in the complementary first and seconddilator engagement members156 and160 so as to translatably attach therefractor member102 to thedilator106. Thus, the first and secondretractor engagement members154 and158 can be referred to as tongues, and the first and seconddilator engagement members156 and160 can be referred to as grooves, such that theattachment mechanism152 defines a tongue-and-groove interface that attaches theretractor member102 to thedilator106. It should be appreciated, of course, that the first and secondretractor engagement members154 and158 can be alternatively configured as desired. For instance, the first and secondretractor engagement members154 and158 can be configured as grooves that are recessed into thebody122, for instance into thesides148 and150. Furthermore, it should be appreciated that the first and seconddilator engagement members156 and160 can be alternatively configured as desired. For instance, the first andsecond dilator156 and160 can be configured as protrusions that extend out from thedilator body108, for instance from the first andsecond sides130 and132, respectively. The engagement members of thedilator106 and theretractor member102 attach such that theretractor member102 is movable with respect to thedilator106. In an embodiment, the engagement members of thedilator106 and theretractor member102 attach such that theretractor member102 can translate relative to thedilator106.

Referring toFIG. 1B andFIGS. 3A-C, theretractor member102 can be attached to thedilator106 by aligning the first and secondretractor engagement members154 and158 with the first and seconddilator engagement members156 and160 along thelongitudinal direction110. Next, one or both of theretractor member102 and thedilator106 can be translated toward the other along the longitudinal direction such that the one of 1) the first and secondretractor engagement members154 and158 and 2) the first and seconddilator engagement members156 and160 is received in the other along a first direction, for instance one of 1) the proximal end of thedilator body108 and the distal end of thebody122, and 2) the distal end of thedilator body108 and the proximal end of thebody122. Once the first and secondretractor engagement members154 and158 are attached to the first and seconddilator engagement members156 and160, therefractor member102 can translate along thelongitudinal direction110 with respect to thedilator106. For instance, theretractor member102 can be positioned such that the distal end of thebody122 can be substantially aligned with the distal end of thedilator body108, or can be offset proximally or distally with respect to the distal end of thedilator body108. Theretractor member102 can be subsequently removed from thedilator106 by translating one of theretractor member102 and thedilator106 with respect to the other along a second direction that is opposite the first direction until theretractor member102 is spaced from thedilator106 along thelongitudinal direction110, which causes the first and secondretractor engagement members154 and158 detach from the first and seconddilator engagement members156 and160. Therefractor member102 can further include a tissue anchor such asshim141. Theshim141 can be configured to be inserted into a tissue portion in order to anchor theretractor member102 to that tissue portion. Theshim141 can be movably secured to an inner surface of theretractor member102. Theretractor member102 further includes one ormore electrodes617 that are configured to detect properties or characteristics of the tissue body. For example, theelectrode617 can monitor the direction, pathology, and proximity of nerves. Theelectrode617 can be attached to a surface of theretractor member102. In the depicted embodiment, theelectrode617 is attached to an outer surface of theretractor member102. Alternatively, theelectrode617 and associated electrical wiring can be embedded in theretractor member102. Theelectrode617 can be configured to be electrically coupled to an electrical power source.

Furthermore, when therefractor member102 is attached to thedilator106, thedilator assembly100 defines apassageway142 that is partially defined by theinner retractor surface134 of thebody122, and is further partially defined by theinner dilator surface126 of thedilator body108. It should be appreciated thatinner retractor surface134 can at least partially cover thechannel116 of thedilator106 so as to define thepassageway142. For instance, theinner retractor surface134 can enclose thechannel116, such that thepassageway142 is enclosed along all directions that are substantially perpendicular to thelongitudinal direction110. Alternatively, theinner retractor surface134 can partially enclose thechannel116, such that a portion of the passageway can be open along a direction substantially perpendicular to thelongitudinal direction110. It can thus be said that thebody122, for instance at theinner retractor surface134, at least partially encloses thechannel116 when theretractor member102 is attached to thedilator106.

Referring now toFIGS. 4A-F, theretractor member102 further includes anengagement assembly162 that is configured to be attached to a portion of aretractor assembly300 as discussed in detail below. Theretractor member102 can include at least oneengagement assembly162 that is carried by thebody122 and configured to attach to aretractor assembly300. Theengagement assembly162 can protrude outward from thebody122 in a direction away from theouter refractor surface136. In the illustrated embodiment, theengagement assembly162 can protrude from thebody122 at or near thefirst end138. Moreover, theengagement assembly162 can be substantially dovetail shaped. It is envisioned, however, theengagement assembly162 can have other suitable shapes as desired. Theengagement assembly162 can include at least one engagement member that is configured to attach to theretractor assembly300. In the depicted embodiment, theengagement assembly162 includes afirst engagement member164 and asecond engagement member163 that is spaced from thefirst engagement member164 along thelateral direction123. The first andsecond engagement members164 and163 can be configured as protrusions.

With continuing reference toFIGS. 4A-F, theretractor member102 can further include alock166 that protrudes outward from theengagement assembly162 in a direction away from theouter retractor surface136. Thelock166 is configured to be attached a portion of theretractor assembly300 as discussed in detail below. Thelock166 can be configured to secure thebody122 to therefractor assembly300. In the illustrated embodiment, thelock166 can be configured as a protrusion that extends from theengagement assembly162, and is disposed between thefirst engagement member164 and thesecond engagement member163. Thelock166 defines a topangled surface169, acentral surface167, and abottom surface165. Thecentral surface167 is connected between the topangled surface169 and thebottom surface165. The topangled surface169 can be configured as a camming surface and can define a plane that is oriented at an oblique angle with respect to thecentral surface167, thebottom surface165, and thelongitudinal direction111. As discussed in detail below, the orientation of the topangled surface169 with respect to thelongitudinal direction111 facilitates attachment of theretractor member102 to therefractor assembly300. Thecentral surface167 can defines a plane that is oriented substantially parallel to thelongitudinal direction111. Thebottom surface165 can define a plane that is oriented substantially orthogonal to thelongitudinal direction111. As discuss in detail below, thebottom surface165 is configured to abut a portion of the retractor assembly so as to lock theretractor member102 to theretractor assembly300.

With reference toFIGS. 5-6D, theretractor member102 can be attached to aretractor assembly300 via the engagement assembly162 (FIG. 6). Theretractor assembly300 includes ahandle302 307, afirst side arm302, a second side arm304, and acentral arm306 that is disposed between thefirst side arm302 and the second side arm304. Thehandle302 307 can be actuated (e.g., squeezed) to move at least one of thefirst side arm302, the second side arm304, or thecentral arm306 relative to each other. Each of thefirst side arm302, the second side arm304, and thecentral arm306 is configured to hold a refractor member, such as theretractor member102. In addition to theretractor member102, theretractor assembly300 can hold acranial retractor member370 and acaudal retractor member372. When coupled to thecentral arm306, therefractor member102 can be referred to as a posterior retractor member. Specifically, thefirst arm302 is configured to hold thecaudal retractor member372, and the second arm304 is configured to hold thecranial refractor member370. Other retractor assemblies can also be used to hold theretractor member102.

With continuing reference toFIGS. 5-6D, thecentral arm306 can be configured to hold theretractor member102. Thecentral arm306 includes acentral arm body308, afirst leg312 that protrudes from thecentral arm body308, and a second leg314 that protrudes from thecentral arm body308. Thefirst leg312 and the second leg314 both protrude from thecentral arm body308 in a rearward direction as indicated by arrow310. Further, thefirst leg312 and the second leg314 are both elongate along the rearward direction indicated by arrow310, and are configured to be connected to at least a section of thehandle302 307 or theretractor body301. Thecentral arm306 can define an outer arm surface309 and anengagement member316, such as clamping device318, that is configured to hold theretractor member102. Specifically, theengagement member316 is configured to attach to theengagement assembly162 so as to attach therefractor member102 to a portion of theretractor assembly300, such as thecentral arm306. Theengagement member316 can include at least one engagement member that is configured to be attached to an engagement member of theretractor member102. For instance, theengagement member316 can include a first engagement member321 and a second engagement member323 that is spaced from the first engagement member321 along a transverse direction311. The first engagement member321 and the second engagement member323 can be referred as grooves that are recessed into the outer arm surface309 of thecentral arm body308. In particular, the first engagement member321 is configured to attach to theengagement member163 of the refractor member, and the second engagement member323 is configured to attach to theengagement member164 of theretractor member102. For instance, theengagement member163 of theretractor member102 can be configured as a protrusion, and the engagement member321 of thecentral arm306 can be configured as a groove that is configured to receive theengagement member163 so as to attach theretractor member102 to thecentral arm306. Similarly, theengagement member164 of theretractor member102 can be configured as a protrusion, and the engagement member323 of thecentral arm306 can be configured as a groove that is configured to receive the engagement member323 so as to attach therefractor member102 to thecentral arm306. Alternatively, the engagement members of theretractor member102 can be configured as grooves, and the engagement members of thecentral arm306 can be configured as protrusions.

With continuing reference toFIGS. 5-6D, theengagement member316 can include a first protrusion320 that at least partially defines the first engagement member321, and a second protrusion322 that at least partially defines the second engagement member323. The first protrusion320 and the second protrusion322 can protrude outward from thecentral arm body308 in a direction away from thefirst leg312 and the second leg314. Specifically, each of the first clamping prong320 and the second clamping prong322 can protrude from thecentral arm body308 generally in a forward direction indicated by arrow324. The first protrusion320 and the second protrusion322 can also be referred to as clamping prongs. Furthermore, the first engagement member321, the second engagement member323, and the outer arm surface309 cooperate to define an engagement opening326 that is configured and sized to receive theengagement assembly162 to hold the retractor member102 (FIG. 6). The cross-section of the engagement opening326 can be substantially dovetail shaped so that the engagement opening326 is configured to receive theengagement assembly162 that is dovetail shaped. The engagement opening326 is also referred to as the substantially dovetail shaped opening.

With reference toFIGS. 4A-6D, theengagement member316 defines afastening indentation330 that extends into the outer arm surface309. Thefastening indentation330 is configured and sized to receivelock166 so as to attach theretractor member102 to a portion of therefractor assembly300, such as thecentral arm306. Thelock166 can be configured to releasably attach therefractor member102 to a portion of theretractor assembly300, such as thecentral arm306. As used herein, the term “indentation” includes, but is not limited to, hole, channel, indentation, notch, depression, a slot, a groove, an opening, a cavity, a void, or any open space that is configured and sized to receive thelock166 so as to attach theretractor member102 to a portion of theretractor assembly300, such as thecentral arm306. Theengagement member316 further includes aretention member332, such adetent334, that is configured to retain thelock166 in thefastening indentation330 so as to attach theretractor member102 to a portion of theretractor assembly300, such as thecentral arm306. Specifically, theretention member332 is configured to abut thebottom surface165 to thereby secure thelock166 in thefastening indentation330. Theretention member332 defines atop surface344 and anangled surface342 that is configured to slide along the topangled surface169 of thelock166 as thelock166 is moved toward thefastening indentation330, thereby facilitating insertion of thelock166 in thefastening indentation166. Theangled surface342 can be referred to as a camming surface, and can define a plane that is oriented at an oblique angle relative to a trans- verse direction indicated by thearrow340. The orientation of theangled surface342 can be complementary to the orientation of the topangled surface169.

With reference toFIGS. 4A-6D, theengagement member316 further includes a biasingmember336, such as aspring338, that is configured to bias theretention member332 in the transverse direction as indicated byarrow340. That is, the biasingmember336 can be configured to bias theretention member332 in a direction away from the retractor body301 (FIG. 2A). The biasingmember336 can be coupled between theretention member332 and aninner surface338 of theengagement member316. Also, the biasingmember336 can be connected between theretention member332 andcentral arm306 so as to bias theretention member332 in a direction away from thecentral arm306. Theretention member332 can also be referred to as a spring-loaded retention member. The biasingmember336 is configured to bias theretention member332 in the direction indicated byarrow340 so that thetop surface344 is in longitudinal alignment with thebottom surface165 of thelock166 to secure theretractor member102 to thecentral arm306.

In operation, thecentral arm306 and theretractor member102 are moved relative to each other so that thelock166 is advanced toward theretention member332 until the topangled surface169 abuts theangled surface342. Thelock166 is then advanced toward thefastening indentation330. As thelock166 is advanced toward thefastening indentation330, theangled surface342 slides along the topangled surface169 to facilitate insertion of thelock166 into thefastening indentation330. While theangled surface342 slides along the topangled surface169, thelock166 urges theretention member332 in a direction opposite to the direction indicated byarrow340 to allow thelock166 to be inserted into thefastening indentation330. Upon further advancement of thelock166 toward thefastening indentation330, thelock166 is no longer positioned over theretention member332. Consequently, the biasingmember336 biases theretention member332 in the transverse direction as indicated byarrow340. As theretention member332 is biased in the transverse direction, thetop surface344 of theretention member332 contacts thebottom surface165 of thelock166, causing thelock166 to be secured within thefastening indentation330. As a consequence, theretractor member102 is attached to thecentral arm306 of theretractor assembly300. Theretractor member102 can be releasably attached to thecentral arm306 of theretractor assembly300. In an alternative embodiment as shown inFIG. 7, thelock166 can include an additionaltop surface346 that is configured to contact aninner surface331 that partially defines thefastening indentation330 so as to further secure thelock166 in thefastening indentation330.

With reference toFIG. 8, in this embodiment, theengagement assembly162 defines ahole105, and theengagement member316 includes afastener348 that is sized to be received in thehole105 so as to attach theretractor member102 to a portion of theretractor assembly300, such as thecentral arm306. It is envisioned that any portion of theretractor member102 can define thehole105. Thus, theretractor member102 can define thehole105. Thefastener348 can be configured as ascrew350, and can include ahead356 and ashaft354 that is connected to thehead356. Theshaft354 and thehead356 can include external threads. Theengagement member316 of thecentral arm306 can define anengagement opening352 that is configured and sized to receive at least a portion of thefastener348, such as theshaft354. Theengagement opening352 can extend through a portion of thecentral arm306 along thelongitudinal direction355. It is envisioned that any portion of theretractor assembly300 can define theengagement opening352. Thus, theretractor member300 defines theengagement opening352. In the depicted embodiment, theengagement opening352 is configured to be aligned with thehole105 such that theengagement opening352 and thehole105 are configured to collectively receive thefastener348 to secure thefirst retractor member102 to theretractor assembly300. Theengagement member316 can further define acavity358 that is disposed in communication with theengagement opening352. Thecavity358 can be configured and sized to receive at least a portion of thefastener348, such as thehead356. Theengagement assembly162 defines atop surface103 and thehole105 that extends into thetop surface103 along thelongitudinal direction355. Thehole105 does not necessarily extend through theretractor member102. Further, thehole105 is configured and sized to receive at least a portion of thefastener348 so as to attach theretractor member102 to a portion of theretractor assembly300, such as thecentral arm306. For example, thehole105 can be configured and sized to receive theshaft354 of thefastener348. In an embodiment, theretractor member102 defies inner threads formed around thehole105 that are configured to mate with external threads formed around theshaft354 to threadedly connect therefractor member102 to thecentral arm306. Theengagement assembly162 can further include anabutment wall360 199, and theengagement member316 can define arecess360 configured and sized to receive at least a portion of theabutment wall199 so as to enhance the stability of the attachment between theretractor member102 and theretractor assembly300. Theengagement member316 can define abottom surface362, therecess360 extends into thebottom surface362. To attach theretractor member102 to thecentral arm306, thefastener348 is inserted into theengagement opening352 and thehole105.

With reference toFIGS. 9A-12B illustrate a method of accessing thesurgical site402, such as thelumbar spine408, in accordance with an embodiment of the present disclosure. Thesurgical site402 can be anintervertebral disc410 that is disposed between twovertebral bodies412. As seen inFIGS. 9A and 9B, anobturator500 and asecond dilator502 can be used in this method of accessing thesurgical site402. Theobturator500 defines a cross-sectional dimension D1, such as a diameter, and is elongate along alongitudinal direction503. Thesecond dilator502 defines a cross-sectional dimension D1, such as a diameter. Thesecond dilator502 defines a cross-sectional dimension D2, such as a diameter, and is elongate along thelongitudinal direction503. The cross-sectional dimension D2 of thesecond dilator502 is greater than the cross-sectional dimension D1 of theobturator500. Thesecond dilator502 defines afirst dilator hole504, such as a bore, that is elongate along thelongitudinal direction503. Thefirst dilator hole504 is configured and sized to receive theobturator500.

Before inserting at least one of theobturator500 or thesecond dilator502, asensor501 can be used to detect the position of nerves in thetissue body400. For example, thesensor501, which can be a neuromonitoring probe, can be inserted laterally and advanced toward thesurgical site402 until itstip505 is inserted into thesurgical site402. As illustrated inFIGS. 9A and 9B, theobturator500 is inserted into thetissue body400. Thesensor501 can also be a triggered electromyography (tEMG) probe. Alternatively,reference number501 can represent a wire such as a Kirschner wire. Next, theobturator500 is advanced toward the desiredsurgical site402 to dilate the portion of thetissue body400 leading to thesurgical site402. Instead of (or in addition to) theobturator500, a Kirschner wire can be inserted through thetissue body400, and then advanced toward thesurgical site402. Thesecond dilator502 is then positioned over theobturator500, and then inserted into thetissue body400. Theobturator500 serves as a guide for thesecond dilator502. Thesecond dilator502 is then advanced toward thesurgical site402 to dilate the portion of thetissue body400 leading toward thesurgical site402. It is envisioned that more than one dilator of increasing cross-sectional dimensions can be used to dilate at least a portion of thetissue body400 in a sequential fashion.

With reference toFIGS. 10A and 10B, thedilator assembly100 defines a cross-sectional dimension D3, such as a diameter. The cross-sectional dimension D3 of thedilator assembly100 is greater than the cross-sectional dimension D2 of thesecond dilator502. After inserting thesecond dilator502 into thetissue body400, thedilator assembly100 is placed over thesecond dilator502, and advanced toward thesurgical site402 to further dilate the portion of thetissue body402 leading toward thesurgical site402. During insertion, thedilator assembly100 can dilate, for example, the psoas muscle. While inserting thedilator assembly100, the user should avoid contacting, impinging, or damaging nerves by using, for example, the sensors as discussed above. Then, thesecond dilator502 and theobturator500 are removed from thetissue body400. Thedilator106 is also removed from thetissue body400 by detaching thedilator106 from theretractor member102. To do so, thedilator106 can be moved in a direction away from thesurgical site402. That is, thedilator106 is moved in a direction indicated byarrow506 so that thefirst engagement member154 slides along theengagement member156, and theengagement member158 slides along theengagement member160 until thedilator106 is detached from theretractor member102.

With reference toFIGS. 11A and 11B, after thedilator106, theobturator500, and thesecond dilator502 are removed from thetissue body400, theretractor member102 is left in its original position. An arm can be used to fix the position of theretractor member102 in thetissue body400. The arm can be connected to an operating table or any other suitable fixed structure. In addition (or alternatively), theretractor member102 can be anchored tointervertebral disc410 using, for example, theshim141.

With reference toFIGS. 12A and 12B, at least a portion of theretractor assembly300 is then inserted in the space dilated by thedilator assembly100 along the direction indicated byarrow508. Specifically, thecranial retractor member370 and thecaudal retractor member372 of theretractor assembly330 are inserted in the space of thetissue body400 that was dilated by thedilator assembly100. Also, thecentral arm306 of theretractor assembly300 is advanced toward theretractor member102 that is disposed in thetissue body400. In particular, thecentral arm306 of theretractor assembly300 is advanced along the direction indicated byarrow508 until at least a portion of thecentral arm306 contacts theretractor member102. Thecentral arm306 can be connected to theretractor member102 as described in detail above. At this point, thecranial retractor member370, thecaudal retractor member372, and theposterior retractor member102 collectively establish a passageway toward thesurgical site402. Then, theretractor assembly300 can be actuated to move theretractor member102, thecranial retractor member370, and thecaudal retractor member372 relative to one another in order to change the size of the passageway.

In one embodiment, the method of accessing the surgical site can include the following steps inserting a dilator assembly into a tissue body, the dilator assembly comprising a dilator and a refractor member removably attached to the dilator; advancing the dilator assembly toward the surgical site to dilate at least a portion of the tissue body; detaching the dilator from the retractor member; removing the dilator from the tissue body while leaving the refractor member in the tissue body; and attaching a retractor assembly to the retractor member disposed in the tissue body.

FIGS. 13A-14B illustrate several steps of a method of accessing thesurgical site402 in accordance with an alternative embodiment of the present disclosure. In this method, theobturator500, thesecond dilator502, and thedilator assembly100 are inserted into thetissue body400, and advanced toward the desiredsurgical site402 as described and illustrated above. Then, theobturator500, thesecond dilator502, and thedilator assembly100 remain in thetissue body400. That is, theobturator500, thesecond dilator502, and thedilator assembly100 are not removed from thetissue body400. Next, thecranial retractor member370 and thecaudal retractor member372 of theretractor assembly330 are placed over thedilator assembly100. Specifically, thecranial retractor member370 and thecaudal retractor member372 are placed over thedilator106, and advanced toward the desiredsurgical site402 in the direction indicated byarrow508. Thecentral arm306 is also advanced toward the desired surgical site until thecentral arm306 contacts theretractor member102. Then,central arm306 can be connected to therefractor member102 as described in detail above.

With reference toFIGS. 14A and 14B, once thecentral arm306 is connected to theposterior retractor member102, theobturator500 and thesecond dilator502 can be removed from thetissue body400. To do so, theobturator500 and thesecond dilator502 can be moved away from the desired surgical site in the direction indicated byarrow509. Thedilator106 is also removed from thetissue body400. To do so, thedilator106 can be moved in a direction away from thesurgical site402. That is, thedilator106 is moved in a direction indicated byarrow509 so that theengagement member154 slides along theengagement member156, and theengagement member158 slides along theengagement member160 until thedilator106 is detached from therefractor member102. After theobturator500, thesecond dilator502, and thedilator106 have been removed from thetissue body400, thecranial retractor member370, thecaudal retractor member372, and theposterior retractor member102 collectively establish a passageway toward thesurgical site402. Then, theretractor assembly300 can be actuated to move theretractor member102, thecranial retractor member370, and thecaudal retractor member372 relative to one another in order to change the size of the passageway.

In one embodiment, the method of accessing thesurgical site400 includes the following steps: inserting a dilator assembly into a tissue body, the dilator assembly comprising a dilator and a refractor member removably attached to the dilator; advancing the dilator assembly toward the surgical site to dilate at least a portion of the tissue body; removing the dilator from the tissue body while leaving the retractor member in the tissue body; and attaching a retractor assembly to the retractor member disposed in the tissue body. The step of attaching the retractor assembly to the retractor member can be performed after the step of removing the dilator from the tissue body. The step of attaching the retractor assembly to the retractor member can be performed before the step of removing the dilator from the tissue body. The dilator can be referred to as the first dilator, and the method can further include the step of advancing a second dilator toward the surgical site to dilate at least a portion of the tissue body. The step of advancing the dilator assembly toward the surgical site can include moving the dilator assembly over the second dilator so that the dilator assembly at least partially surrounds the second dilator. The method can further include advancing an obturator toward the surgical site, wherein the step of advancing the second dilator toward the surgical site includes moving the second dilator over the obturator such that at least a portion of the second dilator surrounds at least a portion of the obturator.

With reference toFIGS. 15A-15B, thetissue retraction system98 can include theretractor assembly300 and adilator assembly600 in accordance with an alternative embodiment of the present disclosure. Thedilator assembly600 can be configured to be inserted to be inserted into atissue body400 so as to at least partially define a passageway toward the desiredsurgical site402. Thedilator assembly600 can include one ormore wires604, such as Kirschner wires, aneuromonitoring device602, and a plurality of dilators. In particular, thedilator assembly600 can include afirst dilator606, asecond dilator608, and athird dilator610. Thethird dilator610 and theneuromonitoring device602 can cooperate so as to define a passageway toward thesurgical site402. The first dilator, thesecond dilator608, and thethird dilator610 can each have substantially tubular shape. Alternatively, the first dilator, thesecond dilator608, and thethird dilator610 can each have substantially partial tubular shape. For example, the first dilator, thesecond dilator608, and thethird dilator610 can each define one or more slots.

Theneuromonitoring device602 can include afirst portion612 and asecond portion614 both of which can be removed from thethird dilator610. Thefirst portion612 can also be referred to as the proximal portion, and thesecond portion614 can be referred to as the distal portion. Thefirst portion612 can be partly or entirely made of a reusable or disposable material. For instance, thefirst portion612 can partly or entirely made of aluminum, polyetheretherketone (PEEK), stainless steel or any other suitable material. Thefirst portion612 and thesecond portion614 can be connected to each other to define theneuromonitoring device602. Thesecond portion614 can be configured as aneuromonitoring member615 that is configured to detect properties or characteristics of thetissue body400. For instance, theneuromonitoring member615 can be used for electromyography (EMG), mechanomyogram (MMG), pressure sensing, vibration sensing, or a combination thereof. Theneuromonitoring device602 can thereby provide output to a user interface so as to provide guidance information to a user that can be used to guide thedilator assembly600 without impinging upon nerve tissue. Theneuromonitoring device602 can be removed from thethird dilator606.

With reference toFIGS. 16A-16D, thedilator assembly600 can include thethird dilator606, which can also be referred to as the dilator, and thefirst portion612 and thesecond portion614 of theneuromonitoring device602. Thedilator606 can have a substantially cylindrical shape and can include adilator body616 that is elongate along a longitudinal direction618. Alternatively, thedilator606 can define a substantially partial cylindrical shape. Thedilator body616 can define afirst dilator end620 and asecond dilator end622 that is spaced from thefirst dilator end620 along the longitudinal direction618. Thefirst dilator end620 can be configured as a proximal dilator end, while thesecond dilator end622 can be configured as a distal dilator end. Thedilator body616 defines anouter dilator surface624 and an opposedinner dilator surface626. Theinner dilator surface626 can define adilator opening628 that is elongate along the longitudinal direction618. Thedilator opening628 can extend through thedilator body616 from thefirst dilator end620 to thesecond dilator end622. Furthermore, thedilator opening628 can be configured and sized to receive another dilator, such as thesecond dilator608. To this end, thedilator opening628 can define a cross-sectional dimension D4. The cross-section dimension D4 can be a diameter. Thedilator616 can be connected to thefirst portion612 and thesecond portion614 as discussed in detail below.

With continuing reference toFIGS. 16A-D, thefirst portion612 can be configured as a retractor member, such as a refractor blade, and includes abody630. In particular, thefirst portion612 can be constructed as a posterior retractor blade. Thebody630 of thefirst portion612 can be elongate along a longitudinal direction632, and can define a first retractor end634 and a second retractor end636 that is spaced from the first retractor end634 along the longitudinal direction632. The first retractor end634 can be configured as a proximal end, while the second retractor end636 can be configured as a distal end. Thebody630 can define anouter surface638 and an opposedinner surface640. Thefirst portion612 can further define a recess642, such as a groove, that extends into theouter surface638. The recess642 can be elongate along the longitudinal direction632. Moreover, the recess642 can extend from thefirst end631 to the second retractor end634 of thebody630. The recess642 can be configured and sized to receive at least a portion of thesecond portion614.

With continuing reference toFIGS. 16A-D, as discussed above, thesecond portion614 can be configured as aneuromonitoring member615 that is configured to sense to detect properties or characteristics of thetissue body400. For instance, theneuromonitoring member615 can be used for electromyography (EMG), mechanomyogram (MMG), pressure sensing, and/or vibration sensing. In an embodiment, theneuromonitoring member615 can include one ormore electrodes617 that are configured to detect properties or characteristic of the tissue body. For example, theelectrode617 can monitor the direction, pathology, and proximity of nerves. Theelectrode617 can be attached to a surface of theneuromonitoring member615. Alternatively, theelectrode617 and associated electrical wiring can be embedded in theneuromonitoring member615. For instance, theelectrode617 and the associated electrical wiring can be embedded in theneuromonitoring member615 during molding. Theneuromonitoring member615 can be configured to be electrically coupled to an electrical power source.

With continuing reference toFIGS. 16A-D, thesecond portion614 includes abody644 that is elongate along a longitudinal direction646, and can define a first end648 and a second end650 that is spaced from the first end648 along the longitudinal direction646. Thebody644 of thesecond portion614 can further define anouter surface652 and an opposedinner surface654. Theelectrode617 can be attached to theouter surface652 of the body. Alternatively, theelectrode617 can be attached to theinner surface654 of thebody644. In another embodiment, theelectrode617 can be embedded in thebody644 as discussed above.

With continuing reference toFIGS. 16A-D, thesecond portion614 can further include anelectrical connection member656, such as wires or a bar, that protrudes from thebody644. Theelectrical connection member656 can transmit electrical energy to theelectrode617 stemming from an electrical power source. Thus, theelectrical connection member656 can be partly or entirely made of an electrically conductive material. In the depicted embodiment, theelectrical connection member656 protrudes from the second end650 of thebody644 along the longitudinal direction646. Theelectrical connection member656 can be elongate along the longitudinal direction646, and can be configured and sized to be received in the recess642 of thefirst portion612. In particular, theelectrical connection member656 can define a first end658 that is attached to thebody644 and a second end660 that can be electrically coupled to an electrical power source via any suitable electrical connection such as a wiring. The first end658 can be spaced from the second end660 along the longitudinal direction646. Theelectrical connection member656 can be bent.

With continuing reference toFIGS. 16A-D, thesecond portion614 can be connected to thefirst portion612 via any suitable connection, such as a snap fit connection. Thefirst portion612 can include one or morefirst engagement members664, and thesecond portion614 can include one or moresecond engagement members662 that are configured to mate with thefirst engagement members664 so as to couple thefirst portion612 to thesecond portion614. In the depicted embodiment, thefirst engagement members662 can be configured as protrusions666, such as pins, that protrude from thebody630 of thefirst portion612. Specifically, the protrusions666 can protrude from thefirst end631 of thebody630 in the longitudinal direction632. The protrusions666 can have a substantially cylindrical shape, and can be elongate along the longitudinal direction666 632. Thesecond engagement members662 can be configured asopenings668 that extend into thebody644. Specifically, theopenings668 can extend into the second end650 of thebody644. Each of theopenings668 is configured to receive a protrusion666 so as to couple thefirst portion612 to thesecond portion614. Thus, when the protrusions666 are inserted into therespective openings668, the protrusions666 andopenings668 define a snap fit connection that is configured to secure thefirst portion612 to thesecond portion614.

With continuing reference toFIGS. 16A-D, as discussed above, thefirst portion612 can be connected to thethird dilator610. In the depicted embodiment, thefirst portion612 can include one ormore engagement members670, and thesecond portion614 can include one ormore engagement members672 that are configured to mate withrespective engagement members670 so as to couple thefirst portion612 to thesecond portion614. Theengagement members670 can be configured asprotrusions674 that protrude from theouter dilator surface624 of thedilator body616. Theprotrusions674 can be configured as rails, and can define a substantially triangular cross-section. In the depicted embodiment, theprotrusions674 can be elongate along the longitudinal direction618, and are disposed closer to thesecond dilator end622 than to thefirst dilator end620. Theengagement members672 of thefirst portion612 can be configured as one ormore recesses676 each configured to securely receive aprotrusion674 so as to couple thefirst portion612 to thedilator610. The insertion of theprotrusions674 in therespective recesses676 causes a friction fit connection between thedilator610 and thefirst portion612. To connect thedilator610 to thefirst portion612, thefirst portion612 can be moved along theouter dilator surface624 in a direction toward the first dilator end622 (i.e., the direction opposite to the longitudinal direction618) such that theprotrusions674 are positioned in therecesses676. Once a significant portion of eachprotrusions674 is disposed in therespective recess676, theprotrusions674 frictionally fit within therecesses676 so as to prevent, or at least inhibit, thefirst portion612 from moving farther along the direction toward thefirst dilator end620. To decouple thefirst portion612 from thedilator610, thefirst portion612 can be moved along theouter dilator surface624 in the longitudinal direction618 until theprotrusions674 are no longer disposed in therecesses676.

With continuing reference toFIGS. 16A-D, as discussed above, thesecond portion614 can be connected to thethird dilator610. In the depicted embodiment, thedilator610 can include one ormore engagement members678, and thesecond portion614 can include one ormore engagement members680 that are configured to mate with theengagement members678 so as to couple thedilator610 to thesecond portion614. Theengagement members678 can be configured asprotrusions682 that protrude from theouter dilator surface624 of thedilator body616. Theprotrusions682 can be configured as rails, and can define a substantially triangular cross-section. In the depicted embodiment, theprotrusions682 can be elongate along the longitudinal direction618, and are disposed closer to thefirst dilator end620 than to thesecond dilator end622. Theengagement members680 can be configured asrecesses684 each of which is configured and sized to securely receive arespective protrusion682 so as to couple thesecond portion614 to thedilator610. The insertion of theprotrusions682 in therespective recesses684 causes a friction fit connection between thedilator610 and thesecond portion614. To connect thedilator610 to thesecond portion614, thesecond portion614 can be moved along theouter dilator surface624 in a direction toward the first dilator end622 (i.e., the direction opposite to the longitudinal direction618) such that theprotrusions682 are positioned in therecesses684. Once a significant portion of eachprotrusion682 is disposed in therespective recess684, theprotrusions682 frictionally fit within therecess684 so as to prevent, or at least inhibit, thesecond portion614 from moving farther along the direction toward thefirst dilator end620. To decouple thesecond portion614 from thedilator610, thesecond portion614 can be moved along theouter dilator surface624 in the longitudinal direction618 until the protrusions are no longer disposed in therecesses684.

With reference toFIGS. 17A-C, thedilator assembly600 can further include thefirst dilator606, thesecond dilator608, thethird dilator610, and thewire604 as discussed above. Each of thefirst dilator606, thesecond dilator608, and thethird dilator610 is configured to dilate thetissue body400. Thewire604 can be configured to secure to the targetsurgical site402, and can guide the movement of thedilators606,608, and610 toward thesurgical site402.

With continuing reference toFIGS. 17A-C, thewire604 can be configured as a Kirschner wire (also known as K-wire) and can be elongate along alongitudinal direction696. Thewire606 can define afirst wire end698 and asecond wire end700 that is spaced from thefirst wire end698 along thelongitudinal direction696. Thewire604 can include ahandle702 that is located closer to thesecond wire end700 than to thefirst wire end698, and can be configured to be grasped by a user in order to facilitate manipulation of the wire by that user. Thewire604 can include apointed tip704 that is configured to be inserted through thetissue body400 and into thesurgical site402. Thepointed tip704 can be located at thefirst wire end698, and can have a substantially tapered configuration. In addition, thepointed tip704 can be configured to be inserted in the intervertebral disc annulus to secure thewire604 to thesurgical site402. Moreover, thewire604 can define anouter wire surface708 that in turn defines a cross-sectional dimension D5, such as a diameter.

With continuing reference toFIGS. 17A-C, thefirst dilator606 can include adilator body706 that defines afirst dilator end710 and asecond dilator end712 that is spaced from thefirst dilator end710 along alongitudinal direction714. Thedilator body706 can be elongate along thelongitudinal direction714, and can be configured to dilate thetissue body400. Thedilator body706 can define anouter dilator surface716 and an opposedinner dilator surface718. Theouter dilator surface716 can define a cross-sectional dimension D6, such as a diameter. Theinner dilator surface718 can define adilator opening720 that extends through thedilator body706. Thedilator opening720 can be elongated along thelongitudinal direction714, and can define a cross-sectional dimension D7, such as a diameter. In the depicted embodiment, thedilator opening720 can be configured and sized to slidably receive thewire604. Thus, the cross-sectional dimension D7 can be greater than or at least substantially similar to the cross-sectional dimension D5. Thefirst dilator606 can further include an electricallyconductive member722 that is at least partially disposed between the dilatorouter surface716 and the dilatorinner surface718. The dilatorouter surface716, the dilatorinner surface718, or both can be partly or entirely made of an electrical insulating material. On the other hand, the electricallyconductive member722 can be partly or entirely made of an electrically conductive material. The electricallyconductive member722 can thus be configured to transmit electrical energy, and can include an exposedportion724 that is not covered by the dilatorouter surface716. The exposedportion724 can be located closer to thesecond dilator end712 than to thefirst dilator end710, and allows the electricallyconductive member720 to be connected to neuromonitoring apparatus or system, such as an EMG clip. Thus, the exposedportion724 can be electrically connected to a neuromonitoring apparatus or system. Thefirst dilator606 can further include anelectrode726 that is electrically coupled to the electricallyconductive member722. Theelectrode726 can be configured to detect properties or characteristics of thetissue body400. In use, theelectrode726 can be used for electromyography (EMG), mechanomyogram (MMG), pressure sensing, and/or vibration sensing. Theelectrode726 can therefore provide output to a user interface so as to provide guidance information to a user that can be used to guide thedilator606 without impinging upon nerve tissue. For instance, theelectrode726 can be configured to monitor the direction, pathology, and proximity of nerves.

With continuing reference toFIGS. 17A-C, thesecond dilator608 can include adilator body686 that is elongate along alongitudinal direction688. Thedilator body686 can define afirst dilator end690 and asecond dilator end692 that is spaced from thefirst dilator end690 along thelongitudinal direction688. Thedilator body686 can define anouter dilator surface728 and an opposedinner dilator surface730. Theouter dilator surface728 can define a cross-sectional dimension D8, such as a diameter. Theinner dilator surface730 can define adilator opening732 that in turn defines a cross-sectional dimension D9, such as a diameter. Thedilator opening732 can be configured and sized to slidably receive thefirst dilator606. Thus, the cross-sectional dimension D9 is greater or at least substantially similar to the cross-sectional dimension D6. Thedilator opening732 can extend through thedilator body686 and can be elongate along thelongitudinal direction688. Furthermore, thesecond dilator608 can include an electricallyconductive member734 that is at least partially disposed between theouter dilator surface728 and theinner dilator surface730. The electricallyconductive member734 can be configured to transmit electrical energy, and can be partly or entirely made of an electrically conductive material. On the other hand, theouter dilator surface728, theinner dilator surface730, or both can be partly or entirely made of an electrically insulting material. The electricallyconductive member734 can include an exposedportion736 that is not covered by theouter dilator surface728. The exposedportion736 can be located closer to thesecond dilator end692 than to thefirst dilator end690, and allows the electricallyconductive member732 to be connected to neuromonitoring apparatus or system, such as an EMG clip. Thus, the exposedportion736 can be electrically connected to a neuromonitoring apparatus or system. Thesecond dilator608 can further include anelectrode738 that is electrically couple to the electricallyconductive member732. Theelectrode738 can be configured to detect properties or characteristics of thetissue body400. In use, theelectrode738 can be used for electromyography (EMG), mechanomyogram (MMG), pressure sensing, and/or vibration sensing. Theelectrode738 can therefore provide output to a user interface so as to provide guidance information to a user that can be used to guide thedilator606 without impinging upon nerve tissue. For instance, theelectrode738 can be configured to monitor the direction, pathology, and proximity of nerves.

With reference again toFIGS. 15A-B, thetissue retraction system98 can be configured to dilate and retract thetissue body400 to establish a passageway toward thesurgical site402. In an embodiment, thetissue retraction system98 can include thedilator assembly600 and theretractor assembly300. Thedilator assembly600 can be configured to dilate thetissue body400 to establish a passageway toward thesurgical site402. Various method and procedures can be employed to dilate and retract thetissue body400 with thetissue retraction system98. For example, thewire604 can be inserted into thetissue body400 and advanced toward the desiredsurgical site402. The advancement of thewire604 into thetissue body400 and toward thesurgical site402 can be guided using fluoroscopy or any other suitable imaging technique. Thewire604 can be inserted into thetissue body400 and advanced toward thesurgical site402 until thepointed tip704 is inserted in an intervertebral disc annulus to thereby anchor thewire604 to the patient. The insertion of thewire604 into thetissue body402 can cause dilation of thetissue body400. Next, thefirst dilator606 can be advanced over thewire604 and toward thesurgical site402. To this end, thefirst dilator606 can be positioned over thewire604 such that thewire604 is disposed in thedilator opening720. During insertion of thefirst dilator606 into thetissue body400, theelectrode726 of thefirst dilator606 can monitor properties or characteristics of thetissue body400 as discussed above. For example, theelectrode726 can monitor the direction, pathology, and proximity of nerves. Theelectrode726 can continue to detect the properties or characteristics of thetissue body400 even after thefirst dilator606 has been placed in the desired position.

Then, thefirst dilator606 can be advanced into thetissue body400 and toward thesurgical site402 in order to dilate thetissue body400 from an initial position to a first dilated position. Then, thesecond dilator608 can be advanced over thefirst dilator606 and toward thesurgical site402 to further dilate thetissue body400. For instance, thesecond dilator608 can be positioned over thefirst dilator606 such that thefirst dilator606 is disposed in thedilator opening732. Then, thesecond dilator608 can be advanced into thetissue body400 and toward thesurgical site402 in order to dilate thetissue body400 from the first dilated position to the second dilated position. During insertion of thesecond dilator608 into thetissue body400, theelectrode738 of thesecond dilator608 can monitor properties or characteristics of thetissue body400 as discussed above. For example, theelectrode738 can monitor the direction, pathology, and proximity of nerves. Theelectrode732 can continue to detect the properties or characteristics of thetissue body400 even after thesecond dilator608 has been placed in the desired position.

Next, thethird dilator610 that is pre-connected to theneuromonitoring device602 can be advanced into thetissue body400 and toward thesurgical site402. Specifically, the pre-connectedthird dilator610 andneuromonitoring device602 can be positioned over thesecond dilator608 such that thesecond dilator608 is disposed in thedilator opening628. Then, the pre-connectedthird dilator610 andneuromonitoring device602 can be advanced over thesecond dilator608 so thatneuromonitoring device602 faces the posterior side of the patient. Thethird dilator610 can be advanced over thesecond dilator608 so that the During insertion of the-connectedthird dilator610 andneuromonitoring device602 into thetissue body400, theelectrode617 can monitor properties or characteristics of thetissue body400 as discussed above. Theelectrode617 can continue to detect the properties or characteristics of thetissue body400 even after theneuromonitoring device602 has been placed in the desired position.

Once thedilator assembly600 has been positioned in the desired location in thetissue body400, thefirst portion612 of theneuromonitoring device602 can be decouple from thethird dilator610 and removed from thetissue body400, while leaving thesecond portion614 in thetissue body400. Thesecond portion614 can be anchored to the surgical site, such as the intervertebral disc annulus, using a shim that slidably coupled to thesecond portion614. The insertion of the shim to a portion of thetissue body400, such as the disc annulus, facilitates securement and stabilization of thesecond portion614 before insertion of theretractor members102 into thetissue body400. The secure and stabilization of thesecond portion614 in thetissue body400 also prevents, or at least minimizes, tissue encroachment from the posterior side of thesecond portion614 because thesecond portion614 is prepositioned and secured before theretractor members102 are introduced into thetissue body400. If necessary or desired, thefirst dilator606, thesecond dilator608, and thewire604 can be removed from thetissue body400. Alternatively, thefirst dilator606 and thesecond dilator608 can be removed from thetissue body400 while leaving thewire604 in thetissue body400. Also, thefirst dilator606, thesecond dilator608, thethird dilator610, and thewire604 can be removed from thetissue body400 while leaving only thesecond portion614 in thetissue body400. Also, thefirst dilator606, thesecond dilator608, and thethird dilator610 can be removed from thetissue body400 while leaving thewire604. Regardless of which components are removed from thetissue body400 at this juncture of the process, thesecond portion614 can remain in thetissue body400. Before connecting theretractor assembly300 to thesecond portion614, theelectrical connection member656 can be bent to avoid interference with theretractor assembly300.

Then, theretractor assembly300 is advanced toward thetissue body400 so that theretractor members102 are advance d toward thesurgical site402. For instance, theretractor members102 can be advanced toward thesurgical site402 such that theretractor members102 are disposed around thewire604, thethird dilator610, or both. While theretractor members102 are advanced into thetissue body400 and toward thesurgical site402, thepartial retractor member303 can be connected to thesecond section614 as discussed above. Then, if necessary, thefirst dilator606, thesecond dilator608, thethird dilator610, thewire604, or a combination thereof, can be removed from thetissue body400, while leaving thesecond portion614neuromonitoring device602 in thetissue body400. As discussed above, theelectrode617 of thesecond portion614 can detect properties or characteristics of thetissue body400. For instance, theelectrode617 can monitor the direction, pathology, and proximity of nerves.

The use of thedilator assembly600 and associated methods as describe above allow continuous neuromonitoring of thetissue body400 during advancement of theretractor members102 into thetissue body400, because thesecond portion614, which contains anelectrode617, remains in thetissue body400 during insertion of theretractor members102 into the tissue body. It is envisioned that theretractor members102 can be constructed as thepartial retractor303, and therefore can be attached to othersecond portions614 that have neuromonitoring capabilities as described above.

With reference toFIGS. 18A-G, theretractor assembly300 can include thepartial retractor member303 that is configured to be coupled to thesecond portion614. Thepartial retractor member303 can cooperate with thesecond portion614 so as to form acomplete retractor member102, which can be constructed as a posterior retractor member. In an embodiment where the second portion is configured as theneuromonitoring member615, the retractor member800 can be configured to be coupled to theneuromonitoring member615 so as to couple theretractor assembly300 to theneuromonitoring member615. Thepartial retractor member303 can cooperate with theneuromonitoring member615 so as to form a complete retractor member, which can be constructed as a posterior retractor member.

With continuing reference toFIGS. 18A-G, thepartial retractor member303 can include abody305 and at least oneengagement assembly162 that is carried by thebody305. Theengagement assembly162 can be substantially similar or identical to theengagement assembly162 described above in connection withFIGS. 4A-F above. Thepartial retractor assembly303 can be coupled to theretractor body301 via theengagement assembly162 as described above. Thebody305 defines anouter surface364 and an opposed inner surface366. Further, thepartial retractor member303 can define a recess368, such as a groove that extends into theouter surface364. The recess368 can be elongate along alongitudinal direction370, and can be configured and sized to receive at least a portion of theneuromonitoring member615 such as a portion of theelectrical connection member656.

With continuing reference toFIGS. 18A-G, thepartial retractor member303 can further include one ormore engagement members374 that are each configured to engage arespective engagement member670 of thedilator610 so as to guide the movement of thepartial retractor member303 along thedilator610 when thepartial retractor member303 is being moved toward theneuromonitoring member615 along thedilator610. Theengagement members374 can be configured asrecesses376 that are each configured to receive arespective protrusion674 of thedilator610.

With continuing reference toFIGS. 18A-G, thepartial retractor member303 can further include afirst engagement member376, asecond engagement member378, and afourth engagement member380. Thefirst engagement member376 can be configured to mate theengagement member662 of theneuromonitoring member615 so as to couple thepartial retractor member303 to theneuromonitoring member615. For example, thefirst engagement member378 can be configured as aprotrusion382, such as a pin, that protrudes from thebody305 along thelongitudinal direction370. Theprotrusion382 can be configured and sized to be securely received in one of theopenings668 of theneuromonitoring member615 so as to couple thepartial retractor member303 to theneuromonitoring member615. Thesecond engagement member378 can be configured to mate arespective engagement member662 of theneuromonitoring member615 so as to couple thepartial retractor member303 to theneuromonitoring member615. For example, thesecond engagement member378 can be configured as aprotrusion384, such as a pin, that protrudes from thebody305 along thelongitudinal direction370. Theprotrusion384 can be configured and sized to be securely received in one of theopenings668 of theneuromonitoring member615 so as to couple thepartial retractor member303 to theneuromonitoring member615. Thethird engagement member380 can be configured as a latch386, which can be hook-shaped. Thelatch380 386 is configured to engage theneuromonitoring member615 through anopening661 of theneuromonitoring member615 so as to couple thepartial retractor member303 to theneuromonitoring member615.

It should be noted that the illustrations and discussions of the embodiments shown in the figures are for exemplary purposes only, and should not be construed limiting the disclosure. One skilled in the art will appreciate that the present disclosure contemplates various embodiments. It should be further appreciated that the features and structures described and illustrated in accordance one embodiment can apply to all embodiments as described herein, unless otherwise indicated. Additionally, it should be understood that the concepts described above with the above-described embodiments may be employed alone or in combination with any of the other embodiments described above.

Claims (32)

What is claimed:

1. A tissue retraction system configured to dilate a tissue body, the tissue retraction system comprising:

a dilator configured to be inserted into the tissue body toward a surgical site, the dilator including a dilator body that is elongate along a respective longitudinal direction and sized to dilate the tissue body, the dilator body defining a proximal end and a distal end that is spaced from the proximal end along the respective longitudinal direction, and the dilator body terminates at first and second dilator sides that extend between the proximal and distal ends, the dilator further including at least one engagement member that is recessed along at least one of the dilator sides;

a first retractor member that includes a body that is elongate along the respective longitudinal direction and at least one engagement member that is configured to attach to the at least one engagement member of the dilator so as to removably attach the first retractor member to the dilator body along the respective longitudinal direction, the first retractor member and the dilator cooperate so as to define a passageway when the first retractor member is attached to the dilator body, wherein one of the at least one engagement members of the dilator and the first retractor member defines a protrusion that is elongate along the respective longitudinal direction and the other of the at least one engagement members of the dilator and the first retractor member defines a groove that is elongate along the respective longitudinal direction and receives the protrusion so as to removably attach the first retractor member to the dilator; and

a retractor assembly including a retractor body and at least a second retractor member that is movably supported by the retractor body, the retractor body configured to be attached to the first retractor member, wherein the retractor body is configured so as to cause the second retractor member to splay away from the first retractor member when the first retractor member is attached to the retractor body.

2. The tissue retraction system as recited inclaim 1, wherein the engagement members of the dilator and the first retractor member attach such that the first retractor member is movable with respect to the dilator along the respective longitudinal direction.

3. The tissue retraction system as recited inclaim 1, wherein the passageway is enclosed along all directions that are substantially perpendicular to the longitudinal direction.

4. The tissue retraction system as recited inclaim 1, wherein the body of the first retractor member defines a proximal end and a distal end that is spaced from the proximal end along the longitudinal direction, the body of the first retractor member terminates at first and second retractor sides that extend between the proximal and distal ends of the body of the first retractor member, and the at least one engagement member of the first retractor member extends out of least one of the retractor sides.

5. The tissue retraction system as recited inclaim 1, wherein the dilator defines first and second protrusions, and the first retractor member defines first and second grooves that are configured to receive the first and second protrusions.

6. The tissue retraction system as recited inclaim 1, wherein the first retractor member includes an engagement assembly that is configured to secure the body of the first retractor member to the retractor assembly.

7. The tissue retraction system as recited inclaim 6, wherein the retractor assembly defines an engagement opening that is configured to receive the engagement assembly to secure the first retractor member to the retractor assembly.

8. The tissue retraction system as recited inclaim 7, wherein the retractor assembly includes a retention member that is configured to retain the engagement assembly in the engagement opening so as to secure the first retractor member to the retractor assembly.

9. The tissue retraction system as recited inclaim 8, wherein the retractor assembly includes a biasing member that is configured to bias the retention member in a direction away from the retractor body.

10. The tissue refraction system as recited inclaim 1, further comprising a fastener that is configured to connect the first retractor member to the retractor assembly.

11. The tissue retraction system as recited inclaim 10, wherein the first retractor member defines a hole, and the retractor assembly defines an engagement opening that is configured to be aligned with the hole such that the engagement opening and the hole are configured to collectively receive the fastener to secure the first retractor member to the retractor assembly.

12. The tissue retraction system as recited inclaim 1, further comprising

a neuromonitoring member configured to detect at least one property of the tissue body, the neuromonitoring member configured to be coupled to the dilator.

13. The tissue retraction system as recited inclaim 12, wherein the dilator body defines an outer dilator surface, and the neuromonitoring member is configured to be coupled along the outer dilator surface.

14. The tissue retraction system as recited inclaim 12, wherein the neuromonitoring member includes at least one electrode that is configured to detect at least one property of the tissue body.

15. The tissue retraction system as recited inclaim 14, wherein the neuromonitoring member includes at least one electrical connection member that is configured to transmit electrical energy to the electrode from an electrical power source.

16. A tissue retraction system configured to dilate a tissue body, the tissue retraction system comprising:

a dilator configured to be inserted into the tissue body toward a surgical site, the dilator including a dilator body that is elongate along a respective longitudinal direction and sized to dilate the tissue body, the dilator further including at least one engagement member;

a first retractor member that includes a body that is elongate along the respective longitudinal direction, at least one engagement member that is configured to attach to the at least one engagement member of the dilator so as to removably attach the first retractor member to the dilator body, wherein the first retractor member and the dilator cooperate so as to define a passageway when the first retractor member is attached to the dilator body, the first retractor member including an engagement assembly; and

a retractor assembly including a retractor body, an engagement opening that is configured to receive the engagement assembly, a retention member that is configured to retain the engagement assembly in the engagement opening so as to secure the first retractor member to the retractor assembly, and a biasing member that is configured to bias the retention member in a direction away from the retractor body, the retractor assembly further including at least a second retractor member that is movably supported by the retractor body such that the second retractor member is moveable away the first retractor member when the first retractor member is secured to retractor assembly.

17. The tissue retraction system as recited inclaim 16, wherein the engagement members of the dilator and the first retractor member attach such that the first retractor member is movable with respect to the dilator along the respective longitudinal direction.

18. The tissue retraction system as recited inclaim 16, wherein the passageway is enclosed along all directions that are substantially perpendicular to the longitudinal direction.

19. The tissue retraction system as recited inclaim 16, wherein one of the at least one engagement members of the dilator and the first retractor member defines a protrusion that is elongate along the respective longitudinal direction, and the other of the at least one engagement members of the dilator and the first retractor member defines a groove that is elongate along the respective the longitudinal direction and receives the protrusion so as to removably attach the first retractor member to the dilator.

20. The tissue retraction system as recited inclaim 16, wherein the dilator body defines a proximal end and a distal end that is spaced from the proximal end along the longitudinal direction, the dilator body terminates at first and second dilator sides that extend between the proximal and distal ends, and the at least one engagement member of the dilator is recessed in at least one of the dilator sides.

21. A tissue retraction system, comprising:

a dilator having a dilator body that defines a proximal end, a distal end that is spaced from the proximal end along a respective longitudinal direction, an inner surface, and an outer surface, the dilator including an electrode, the dilator body terminating at first and second dilator sides that extend between the proximal and distal ends, the dilator including at least one engagement member that is recessed along at least one of the dilator sides;

a retractor member having a body that defines a proximal end, a distal end, at least one engagement member that is configured to attach to the at least one engagement member of the dilator so as to removably attach the retractor member to the dilator body along the respective longitudinal direction, and a retractor member opening that extends through the body from the proximal end to the distal end, the retractor member opening being configured to receive the dilator therethrough, wherein one of the at least one engagement members of the dilator and the retractor member defines a protrusion that is elongate along the respective longitudinal direction and the other of the at least one engagement member of the dilator and the retractor member defines a groove that is elongate along the respective longitudinal direction and receives the protrusion so as to removably attach the retractor member to the dilator; and

a mechanomyogram (MMG) neuromonitoring system, the electrode of the dilator being electrically coupled to an electrically conductive member extending longitudinally along the dilator, the electrically conductive member being connected to the MMG neuromonitoring system.

22. The system of claim 21, wherein the retractor member defines a circumferentially-enclosed working channel that extends from the proximal end to the distal end of the body.

23. The system of claim 21, wherein the electrode is configured to detect properties or characteristics of tissue in which the first dilator is disposed.

24. The system of claim 21, wherein the electrode is configured to provide output to a user interface so as to provide guidance information to a user that can be used to guide the first dilator without impinging upon nerve tissue.

25. The system of claim 21, wherein the electrode is configured to monitor the direction, pathology, and proximity of nerves.

26. The system of claim 21, wherein the electrode is configured to continue to detect the properties or characteristics of tissue after the dilator is placed in a desired position.

27. The system of claim 21, wherein the dilator is longer than the retractor member.

28. The system of claim 21, wherein the retractor member is tubular.

29. The system of claim 21, wherein the dilator includes a curved outer surface that mates with a curved inner surface of the retractor member.

30. The system of claim 21, wherein an inner diameter of the retractor member is greater than an outer diameter of the dilator.

31. The system of claim 21, wherein the dilator is longitudinally movable relative to the retractor member.

32. The system of claim 21, wherein the dilator and the retractor member are movable relative to one another to dilate tissue.

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