US20140296869A1 - Surgical instrument shaft - Google Patents

Abstract

A surgical instrument may include a shaft, a force transmission mechanism, and an end effector. The shaft may have a proximal end and a distal end. The force transmission mechanism may be coupled to the proximal end of the shaft. The end effector may be coupled to the distal end of the shaft. The shaft may include a body having an outer surface and an inner surface. The inner surface may surround a lumen configured to receive a drive member that extends through the lumen. The outer surface of the body may form an outer surface of the shaft. The body may be made of a single material from the inner surface of the body to the outer surface of the body.

Description

• This application claims the benefit of U.S. Provisional Application No. 61/781,679, filed on Mar. 14, 2013, which is incorporated by reference herein in its entirety.
TECHNICAL FIELD
• Aspects of the present disclosure relate to a surgical instrument, for example for use with a teleoperated (robotic) surgical system. In particular, aspects of the present disclosure relate to the shaft construction of such a surgical instrument.
INTRODUCTION
• Some minimally invasive surgical techniques are performed remotely through the use of teleoperated (robotically-controlled) surgical instruments (which may also be referred to as tools). In teleoperated surgical systems, surgeons manipulate input devices at a surgeon console, and those inputs are passed to a patient side cart that interfaces with one or more teleoperated surgical instruments. Based on the surgeon's inputs at the surgeon console, the one or more surgical instruments are actuated at the patient side cart to operate on the patient, thereby creating a master-slave control relationship between the surgeon console and the surgical instrument(s) at the patient side cart.
• Teleoperated surgical systems may have multiple arms to which teleoperated surgical instruments may be coupled. Because the surgical instruments may be used within a relatively small space inside of a patient during a surgical procedure, and because it is desirable to minimize the size of incisions and ports through which a surgical instrument may be passed to access the surgical site, and to otherwise minimize the invasiveness of a surgical procedure, components of a surgical instrument can be relatively small in size. Although components of a surgical instrument may be relatively small, it remains desirable that the components exhibit properties that allow them to perform various functions that may be required during a surgical procedure. To some degree, the issues of size and functionality may provide countervailing considerations when designing and manufacturing a surgical instrument. In view of these considerations, it may be desirable to provide a surgical instrument that has a robust design and provides mechanical properties that support the functions for which a surgical instrument may be used. It also may be desirable to provide such a surgical instrument that facilitates manufacture.
SUMMARY
• Exemplary embodiments of the present disclosure may solve one or more of the above-mentioned problems and/or may demonstrate one or more of the above-mentioned desirable features. Other features and/or advantages may become apparent from the description that follows.
• In accordance with at least one exemplary embodiment, a surgical instrument comprises a shaft, a force transmission mechanism, and an end effector. The shaft may have a proximal end and a distal end. The force transmission mechanism may be coupled to the proximal end of the shaft. The end effector may be coupled to the distal end of the shaft. The shaft may include a body having an outer surface and an inner surface. The inner surface may surround a lumen configured to receive a drive member that extends through the lumen. The outer surface of the body may form an outer surface of the shaft. The body may be made of a single material from the inner surface of the body to the outer surface of the body.
• In accordance with at least one exemplary embodiment, a surgical instrument comprises a shaft, a force transmission mechanism, and an end effector. The shaft may have a proximal end and a distal end. The force transmission mechanism may be coupled to the proximal end of the shaft. The end effector may be coupled to the distal end of the shaft. The shaft may include a body having an outer surface that forms an outer surface of the shaft and an inner surface that defines a lumen that a drive member extends through. The body may have a single piece construction.
• In accordance with at least one exemplary embodiment, a method of manufacturing a shaft for a surgical instrument comprises extruding a material to form a body of a shaft. The body may have an outer surface and an inner surface that forms a lumen configured to receive a drive member that extends through the lumen. The outer surface of the body may form an outer surface of the shaft. The body may be made of a single material from the inner surface of the body to the outer surface of the body.
• Additional objects, features, and/or advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present disclosure and/or claims. At least some of these objects and advantages may be realized and attained by the elements and combinations particularly pointed out in the appended claims.
• It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims; rather the claims should be entitled to their full breadth of scope, including equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present disclosure can be understood from the following detailed description, either alone or together with the accompanying drawings. The drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more exemplary embodiments of the present teachings and together with the description serve to explain certain principles and operation.
• FIG. 1 is a schematic view of an exemplary embodiment of a portion of a manipulator supporting a curved cannula and a surgical instrument.
• FIG. 2 is a top schematic view of an exemplary embodiment of a surgical instrument including a force transmission mechanism.
• FIG. 3 is an exploded view of an exemplary embodiment of a shaft of a surgical instrument.
• FIG. 4 is a cross-sectional view of the shaft ofFIG. 3 taken along line4-4.
• FIG. 5 is a cross-sectional view of an exemplary embodiment of a shaft of a surgical instrument.
• FIG. 6 is a cross-sectional view of another exemplary embodiment of a shaft of a surgical instrument.
• FIG. 7 is a cross-sectional view of yet another exemplary embodiment of a shaft of a surgical instrument.
• FIG. 8 is a cross-sectional view of an exemplary embodiment of a sheathed shaft of a surgical instrument.
• FIG. 9 is a cross-sectional view of another exemplary embodiment of a sheathed shaft of a surgical instrument.
• FIG. 10 is a cross-sectional view of yet another exemplary embodiment of a sheathed shaft of a surgical instrument.
• FIG. 11 is a schematic side view of a surgical instrument inserted to a maximum distance within a curved cannula, according to an exemplary embodiment.
• FIG. 12 is a schematic side view of a surgical instrument inserted to a minimum distance within a curved cannula, according to an exemplary embodiment.
• FIG. 13 is a cross-sectional view of another exemplary embodiment of a shaft of a surgical instrument.
DETAILED DESCRIPTION
• Exemplary embodiments discussed herein regard a surgical instrument for a teleoperated surgical system. The surgical instrument may facilitate manufacture, while providing a robust design with properties that support the functions for which the instrument is intended. In various exemplary embodiments, for example, a shaft of the surgical instrument may be configured to have a substantially uniform stiffness. Further, various exemplary embodiments enable substantial consistency in the manufacture of one shaft to the next.
• This description and the accompanying drawings that illustrate exemplary embodiments should not be taken as limiting. Various mechanical, compositional, structural, electrical, and operational changes may be made without departing from the scope of this description and the invention as claimed, including equivalents. In some instances, well-known structures and techniques have not been shown or described in detail so as not to obscure the disclosure. Like numbers in two or more figures represent the same or similar elements. Furthermore, elements and their associated features that are described in detail with reference to one embodiment may, whenever practical, be included in other embodiments in which they are not specifically shown or described. For example, if an element is described in detail with reference to one embodiment and is not described with reference to a second embodiment, the element may nevertheless be claimed as included in the second embodiment.
• For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages, or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about,” to the extent they are not already so modified. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
• It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” and any singular use of any word, include plural referents unless expressly and unequivocally limited to one referent. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.
• Teleoperated surgery generally involves the use of a manipulator that has multiple manipulator arms. One or more of the manipulator arms often support a teleoperated surgical instrument that is ultimately placed in a master-slave relationship with master controllers at a surgeon console, such that inputs by a surgeon at the surgeon console are provided as signals to control movement of the surgical instruments. One or more of the manipulator arms typically also is used to support a surgical image capture device, such as a camera endoscope (which may be any of a variety of structures such as a laparoscope, an arthroscope, a hysteroscope, or the like), or, optionally, some other imaging modality (such as ultrasound, fluoroscopy, magnetic resonance imaging, or the like) so as to provide the surgeon with a view of the remote surgical site. Typically, at least three manipulator arms will respectively support two surgical tools (corresponding to the two hands of a surgeon) and an image capture device. Reference is made to U.S. application Ser. No. 12/618,583, entitled “Curved Cannula Surgical System,” filed on Nov. 13, 2009 and published as U.S. Pub. No. US 2011/0071542 on Mar. 24, 2011, now issued as U.S. Pat. No. 8,545,515, which is hereby incorporated by reference in its entirety, for examples of a teleoperated surgical system.
• Turning toFIG. 1, a schematic view of a portion of a patient side manipulator (or “PSM”) that supports and moves a combination of a curved cannula and a passively flexible surgical instrument is shown, according to an exemplary embodiment. As depicted inFIG. 1, asurgical instrument110 includes aforce transmission mechanism112, aflexible shaft114, and anend effector116. According to an exemplary embodiment,shaft114 ofinstrument110 may be passively flexible.Instrument110 is mounted on aninstrument carriage assembly102 ofmanipulator100.Interface discs104 couple actuation forces from servo actuators inmanipulator100 to moveinstrument110 components.
• According to an exemplary embodiment,end effector116 operates with a single degree of freedom (DOF) (e.g., closing jaws). According to an exemplary embodiment,instrument110 may include a wrist structure (not shown) to provide one or more end effector DOF's (e.g., pitch, yaw; see e.g., U.S. Pat. No. 6,817,974 (filed Jun. 28, 2002) (disclosing “Surgical Tool Having Positively Positionable Tendon-Actuated Multi-Disk Wrist Joint”), which is incorporated herein by reference). Aninstrument110, as shown in the exemplary embodiment ofFIG. 1, lacking a wrist may be referred to as a non-wristed instrument. Omitting a wrist, for example, can simplify the number of actuation force interfaces betweenmanipulator100 andinstrument110; such omission can also reduce the number of force transmission elements (and hence, instrument complexity and dimensions) that would be utilized between the proximalforce transmission mechanism112 and the distally actuatedend effector116 in order to actuate a wrist structure.
• FIG. 1 further shows acurved cannula120, which has aproximal end122, adistal end124, and acentral channel126 that extends betweenproximal end122 anddistal end124. According to an exemplary embodiment,curved cannula120 is a rigid, single piece cannula.Curved cannula120 may include one or morestraight sections121 and one or morecurved sections123, according to an exemplary embodiment. According to an exemplary embodiment,curved cannula120 may be curved (not shown) fromproximal end122 todistal end124. Acurved section125 of acurved cannula120 may have a curvature with an angle between ends ofsection125, for example, ranging from about 40° to about 65°. In another example,curved section125 may have a curvature ranging from about 45° or about 60°.Curved section123 may have acenterline radius127, shown in the exemplary embodiment ofFIG. 1, ranging from about 4.50 inches to about 5.50 inches, for example.
• As depicted in the exemplary embodiment ofFIG. 1,proximal end122 ofcurved cannula120 is mounted on acannula mount106 ofmanipulator100. During use,flexible shaft114 ofinstrument110 extends through thecentral channel126 ofcurved cannula120 so that a distal portion offlexible shaft114 andend effector116 extend beyonddistal end124 ofcannula120 in order to reach asurgical site130. Constraints of manipulator100 (whether mechanical and/or preprogrammed software constraints in the control system for manipulator100)cause instrument110 andcurved cannula120 to move in pitch and yaw around remote center ofmotion140 located alongcannula120, which may be located at an incision or port in a patient's body wall. The I/O actuation ofmanipulator100, provided bycarriage102, inserts and withdrawsinstrument110 throughcannula120 to moveend effector116 in and out.
• FIG. 2 depicts a top view of an exemplary embodiment of asurgical instrument200 for a teleoperated surgical system.Surgical instrument110 ofFIG. 1 may be configured according to the exemplary embodiment ofFIG. 2.Surgical instrument200 may include aforce transmission mechanism210, ashaft222 connected to forcetransmission mechanism210 at aproximal end223 ofshaft222, and anend effector220 connected to adistal end224 ofshaft222.Surgical instrument200 may include one or more members to translate force betweenforce transmission mechanism210 andend effector220. For instance, one or more drive member(s)226 may connectforce transmission mechanism210 to endeffector220 to provide actuation forces to endeffector220, such as by extending through an interior ofshaft222.
• By utilizing drive member(s)226,force transmission mechanism210 may actuateend effector220, for example, to control a wrist structure (if any) ofinstrument200 and/or to control a jaw of end effector220 (or other moveable part). Further, becauseend effector220 may be fixed toshaft222, force translated fromforce translation mechanism210 to endeffector220 may in turn be translated toshaft222, such as whenforce translation mechanism210 actuatesend effector220 andshaft222 in a rolling motion. Drive member(s)226 may be in the form of tension elements, such as whenforce transmission mechanism210 is a pull-pull mechanism, as described in U.S. Pub. No. US 2011/0071542, or one or more drive element rods, such as whenforce transmission mechanism210 is a push-pull mechanism, as described in U.S. Pub. No. US 2011/0071542.
• Force transmission mechanism210 may include one or more components to engage with a patient side cart of a teleoperated surgical system to translate a force provided by patient side cart tosurgical instrument200. According to an exemplary embodiment,force transmission mechanism210 may include one ormore interface disks212,214 that engage with a manipulator of a patient side cart, as discussed above in regard to the exemplary embodiment ofFIG. 1. Thus,interface disks212,214 utilize actuation forces from a manipulator to actuateinstrument200. For instance,first disk212 may be configured to provide a rolling motion toshaft222 and provide a roll DOF forend effector220, whilesecond disk214 may operate a jaw mechanism ofend effector220 to open and close. However, these particular actuation schemes/controls are exemplary only and other configurations are envisioned, depending on the type of instrument and motions for use of such instruments.
• As discussed above, a shaft of a surgical instrument may be flexible. Flexibility, for example, may assist with inserting the instrument through a curved cannula. However, the instrument shaft may also be required to support an end effector when the distal end of the shaft and the end effector are extended beyond a distal end of the curved cannula. For instance, theshaft114 ofinstrument110 shown in the exemplary embodiment ofFIG. 1 may be flexible to permitinstrument110 to be inserted and withdrawn throughcurved cannula120 but also be sufficiently stiff to provide effective surgical action at asurgical site130. As a result,flexible shaft114 ofinstrument110 may be extended through thecentral channel126 ofcurved cannula120 so that a distal portion offlexible shaft114 andend effector116 extend beyond thedistal end124 ofcannula120 to reachsurgical site130. In view of these considerations, a shaft of a surgical instrument may include structures to affect the flexibility and stiffness of the shaft.
• Some shaft configurations utilize multiple parts to provide a shaft that is flexible, such as to facilitate passing an instrument through a curved cannula, but also stiff, such as to support an end effector. Further, the shaft may include paths to route cabling and other instrument control mechanisms from a proximal end to a distal end. Turning toFIG. 3, an exploded view of an exemplary embodiment of ashaft300 for a surgical instrument is shown.Shaft300 may include anouter tube302 and a channeledinsert306 sized to be contained inside of theouter tube302. Turning toFIG. 4, which is a cross-sectional view along line4-4 inFIG. 3, channeledinsert306 may include alumen307 for adrive member310 connecting a force transmission mechanism to an end effector of the surgical instrument, as discussed in the exemplary embodiments ofFIGS. 1 and 2. For instance,drive member310 may be a drive element rod, such as when the force transmission mechanism is a push-pull mechanism to actuate the end effector. Channeledinsert306 may be provided withinouter tube302 to support and locatedrive member310 withinouter tube302. According to an exemplary embodiment,outer surface305 offirst tube302 may form an outer surface of the shaft.
• Outer tube302 may be constructed to provide a degree of stiffness and flexibility toshaft300. For instance,outer tube302 may be made of a relatively durable and stiff material that is relatively flexible. For example,outer tube302 may comprise polyether ether ketone (PEEK) or other similar materials used in the art for the tubes of surgical instrument shafts. Theinsert306 may be constructed so thatinsert306 is more compliant and flexible thanouter tube302. For instance, it may be desirable forinsert306 to be more compliant and flexible thanouter tube302 to facilitate insertion ofinsert306 withinouter tube302. To accomplish this, insert306 may be made of a material that is more compliant than the material ofouter tube302. For example, insert306 may comprise fluorinated ethylene propylene (FEP).
• Outer tube302 and insert306 may be sized and arranged relative to one another to provide lumens within theinstrument shaft300 betweenouter tube302 and insert306. As shown in the exemplary embodiment ofFIG. 4,outer tube302 and insert306 may be configured to provide one ormore lumens301 betweenouter tube302 and insert306.Lumen301 may be used, for instance, as a passage for cleaning fluid to flush an interior ofshaft300 during a procedure to clean a surgical instrument. According to an exemplary embodiment,shaft300 may include one ormore conduits312 to provide a flux to an end effector of a surgical instrument. In such embodiments,tube302 and insert306 may provide one ormore lumens303 for the one ormore conduits312. A flux may be, for example, a form of energy, suction, irrigation fluid, or other flux used with surgical instruments. For instance, if a surgical instrument is an electrosurgical instrument, such as for cauterization procedure, the one ormore conduits312 may be wires to provide electrical energy to an end effector.
• Becauseinsert306 is relatively compliant and flexible, particularly in comparison toouter tube302, insert306 may be altered to increase the stiffness ofinsert306. For instance, insert306 may include one or more structures to increase the stiffness ofinsert306. As shown in the exemplary embodiment ofFIGS. 3 and 4, one ormore wires308 may be inserted withinlumens309 ofinsert306 to increase the stiffness ofinsert306. According to an exemplary embodiment,wires308 may be made of a material having a higher stiffness than the material ofinsert306. For example,wires308 may be made of a metal. In another example,wires308 may be made of a stainless steel, such astype 304 stainless steel. Stiffening wires may extend the length ofshaft300, such as fromproximal end223 todistal end224, as shown in the exemplary embodiment ofFIG. 2. As shown in the exemplary embodiment ofFIGS. 3 and 4,shaft300 may include four stiffeningwires308, althoughshaft300 is not limited to this number ofwires308 and the number and type of stiffening structures may be selected as desired.
• According to an exemplary embodiment,shaft300 may include asheath304 located on an outer surface offirst tube302.Sheath304 may be provided to affect the coefficient of friction ofshaft300, such as by providing a smooth surface that facilitates insertion of an instrument within a cannula. In various exemplary embodiments,sheath304 may be made of ethylene tetrafluoroethylene (ETFE) or other sheath materials that are used in the art.
• Asurgical instrument shaft300 having a construction shown in the exemplary embodiment ofFIGS. 3 and 4 can be both compliant enough to be advanced and withdrawn through a curved cannula, while being stiff enough to support the functions of an end effector connected to a distal end ofshaft300. However,shaft300 includes numerous components, which can be made of different materials. In addition, manufacture ofshaft300 may require numerous steps. As a result,shaft300 may be relatively costly to manufacture due to the complexity of its production process and the different materials utilized.
• Another consideration for theshaft300 of the exemplary embodiment ofFIGS. 3 and 4 is the ease of controlling the properties ofshaft300. Manufacturing processes and tolerances may make manufacture ofshaft300 relatively difficult, particularly whenshaft300 includes multiple pieces, such asouter tube302, insert306, andwires308. For instance, manufacturing processes and tolerances of the dimensions of shaft components in both a radial direction and an axial direction along the length of the shaft may affect the overall stiffness of the shaft.
• In view of these considerations, various exemplary embodiments contemplate a surgical instrument having a shaft that is relatively easy and inexpensive to manufacture and exhibits an overall stiffness that enhances control of the instrument during use and is substantially uniform from one shaft to another. Various exemplary embodiments may provide a surgical instrument that exhibits enhanced motion control and minimal unintended movement of an end effector, such as indirections230,232 shown in the exemplary embodiment ofFIG. 2, during the use of the end effector of the instrument.
• Turning toFIG. 5, an exemplary embodiment of asurgical instrument shaft400 is shown in cross-section.Shaft400 may be used for an instrument discussed in the exemplary embodiments ofFIGS. 1 and 2. As shown inFIG. 5,shaft400 may include anouter tube402 and aninner tube404. According to an exemplary embodiment,shaft400 may have a body that is provided byinner tube404 andouter tube402. For instance, the body ofshaft400 may extend between aninner surface409 ofinner tube404 to anouter surface401 ofouter tube402. Thus,inner surface409 may form an inner surface of the body ofshaft400 andouter surface401 may form an outer surface of the body ofshaft400. According to an exemplary embodiment, each ofinner tube404 andouter tube402 may be made by extruding a material to form a hollow cylinder, as shown inFIG. 5.
• According to an exemplary embodiment,inner tube404 may have a wall thickness that is substantially the same as the wall thickness ofouter tube402. According to another example embodiment,inner tube404 andouter tube402 have different wall thicknesses. For instance,inner tube404 may have a greater wall thickness or a smaller wall thickness thanouter tube402.
• Outer tube402 andinner tube404 may each have a form of a hollow cylinder, according to an exemplary embodiment. As shown in the exemplary embodiment ofFIG. 5,outer tube402 may be continuously solid between itsinner surface403 and itsouter surface401 and thus lack any lumen (i.e., be lumenless). Similarly, inner tube may be solid and lack any lumen between itsouter surface405 and itsinner surface409, as shown in the exemplary embodiment ofFIG. 5.
• Inner tube404 may include alumen407 that is configured to receive adrive member406 connecting a force transmission mechanism to an end effector of the surgical instrument, as discussed in the exemplary embodiments ofFIGS. 1 and 2. Aninner surface409 ofinner tube404 that formslumen407 can be in contact withdrive member406, according to an exemplary embodiment. According to an exemplary embodiment,lumen407 may have a diameter ranging from about 0.030″ to about 0.050″. According to another exemplary embodiment,lumen407 may have a diameter ranging from about 0.035″ to about 0.045″. According to an exemplary embodiment, a diameter ofshaft400 may be about 5 to about 5.5 times the diameter oflumen407.
• According to an exemplary embodiment, anouter surface401 ofouter tube402 may form an outer surface ofshaft400. For instance,outer surface401 may be uncovered or otherwise exposed to a surrounding environment. As shown in the exemplary embodiment ofFIG. 5,outer surface401 may have a substantially circular cross-section. According to an exemplary embodiment,shaft400 may consist ofdrive member406,inner tube404, andouter tube402.
• Tubes402,404 may be provided, for example, as hollow cylinders, as shown in the exemplary embodiment ofFIG. 5, that have similar shapes and are concentric. According to an exemplary embodiment, aninner surface403 ofouter tube402 and anouter surface405 ofinner tube404 may have substantially the same radius of curvature. Althoughinner tube404 andouter tube402 are in contact with one another,inner tube404 andouter tube402 may be configured to move relative to one another to facilitate bending ofshaft400. For instance,inner tube404 andouter tube402 may be configured to slide relative to one another, such as along the proximal-distal direction shown in the exemplary embodiment ofFIG. 2, whenshaft400 is bent.
• According to an exemplary embodiment,tubes402,404 may have similar or substantially the same stiffness values. As a result,inner tube404 may function as a stiffening tube forouter tube402 and may provide a sufficient stiffness to the shaft so as to enable support of the end effector as discussed above. Utilizing theinner tube404 as a mechanism for stiffening theouter tube402 can reduce the number of other additional stiffening members that may be used and the overall number of components of the surgical instrument shaft.
• According to an exemplary embodiment,inner tube404 andouter tube402 may comprise the same material, such as, for example, PEEK. Use of the same or similar materials that provide sufficient stiffness properties for both theinner tube402 andouter tube404 may further provide the shaft with an overall stiffness that is substantially uniform from one shaft to another during a manufacturing process.
• Turning toFIG. 6, an exemplary embodiment of ashaft500 of a surgical instrument is shown in cross section.Shaft500 may include anouter tube502 and aninner tube504.Inner tube504 may include alumen507 for adrive member506 connecting a force transmission mechanism to an end effector of the surgical instrument, as discussed in the exemplary embodiments ofFIGS. 1 and 2. Aninner surface509 ofinner tube504 that defineslumen507 may be in contact withdrive member506, according to an exemplary embodiment.
• Outer tube502 andinner tube504 may be connected by a plurality ofribs510. As shown in the exemplary embodiment ofFIG. 6,ribs510,inner tube504, andouter tube502 may define one ormore lumens508.Lumens508 may be used, for example, for flushing fluid in a cleaning operation. In another example,lumens508 may serve as passages, such as for one ormore conduits512 to provide a flux to an end effector of a surgical instrument. According to an exemplary embodiment, anouter surface501 ofouter tube502 may define an outer surface ofshaft500. Further, according to an exemplary embodiment,shaft500 may consist ofinner tube504,outer tube502, at least onerib510, at least onelumen508, and drivemember506. According to another exemplary embodiment,shaft500 may includeinner tube504,outer tube502, at least onerib510, at least onelumen508, at least oneconduit512, and drivemember506.
• A body ofshaft500 may be formed byinner tube504,outer tube502, andribs510. To provide an instrument shaft that advantageously includes fewer components, is less difficult to manufacture, and is less costly to manufacture, instrument shaft500 (not including drive member506) may have a single piece construction. Thus, the body ofshaft500 formed byinner tube504,outer tube502, andribs510 may be formed as a single piece. According to an exemplary embodiment, the body formed byinner tube504,outer tube502, andribs510 may be defined by a single piece formed in an extrusion process. According to an exemplary embodiment, the body formed byinner tube504,outer tube502, andribs510 may be made of the same material. For instance, the body ofshaft500 may be formed from a single material betweeninner surface509 andouter surface501. Thus,inner surface509 may form an inner surface of the body ofshaft500 andouter surface501 may form an outer surface of the body ofshaft500. According to an exemplary embodiment, anouter surface501 ofouter tube502 may form an outer surface ofshaft500. For instance,outer surface501 may be uncovered or otherwise exposed to a surrounding environment. As shown in the exemplary embodiment ofFIG. 6,outer surface501 may have a substantially circular cross-section.
• The stiffness ofshaft500 may be varied, for example, by altering the dimensions ofshaft500. For instance, a thickness ofinner tube504,outer tube502, and/orribs510 may be varied to affect the stiffness ofshaft500.Inner tube504 may have a thickness of, for example, about 0.095 inches to about 0.105 inches.Outer tube502 may have a thickness of, for example, about 0.030 inches to about 0.040 inches.Ribs510 may have a thickness of about 0.020 inches to about 0.030 inches. According to an exemplary embodiment, the material ofinner tube504,outer tube502, andribs510 may be selected to provide a desired stiffness forshaft500. Another method of controlling the stiffness ofshaft500 is selecting the number ofribs510, according to an exemplary embodiment. As shown in the exemplary embodiment ofFIG. 6,shaft500 may include fourribs510. However, a shaft for a surgical instrument may include, for example three ribs, five ribs, or other numbers of ribs.
• Further, althoughshaft500 may lack stiffening wires, which may be made out of a material having a relatively high stiffness, such as a metal, and thusshaft500 may be expected to have a lower overall stiffness,shaft500 has a sufficient stiffness but advantageously exhibits an overall stiffness that is more easily controlled and more uniform from one shaft to another in comparison to shafts including stiffening wires. As a result,shaft500 advantageously enhances movement control and minimizes movement of end effector during actuation of the end effector, such as indirections230,232 discussed above in regard toFIG. 2.
• Turning toFIG. 7, an exemplary embodiment of ashaft600 of a surgical instrument is shown in cross section.Shaft600 may be defined by asingle tube602 that includes alumen601 for adrive member604 connecting a force transmission mechanism to an end effector of the surgical instrument, as discussed in the exemplary embodiments ofFIGS. 1 and 2. According to an exemplary embodiment,lumen601 may be utilized during a cleaning operation by flushing material throughlumen601. Aninner surface605 oftube602 that defineslumen601 may be in contact withdrive member604, according to an exemplary embodiment.
• According to an exemplary embodiment,tube602 may be provided as a single piece tube. Thus, a body ofshaft600 may be formed bytube602. Further, as shown in the exemplary embodiment ofFIG. 7,tube602 may be a continuously solid hollow cylinder between theouter surface603 oftube602 and theinner surface605 oftube602 and thus lack any lumen (i.e., be lumenless). In other words,tube602 may be a hollow cylinder that includes a single lumen, namely lumen601 fordrive member604. According to an exemplary embodiment,outer surface603 oftube602 may define an outer surface ofshaft600. For instance,outer surface603 may be uncovered or otherwise exposed to a surrounding environment. As shown in the exemplary embodiment ofFIG. 6,outer surface501 may have a substantially circular cross-section.
• According to an exemplary embodiment,tube602 may be made from a single material. Thus, a body ofshaft600 may be made from a single material betweeninner surface601 andouter surface603. Further,inner surface601 may form an inner surface of the body ofshaft600 andouter surface603 may form an outer surface of the body ofshaft600. According to an exemplary embodiment,tube602 may be made by extruding a single material to form a hollow cylinder, as shown inFIG. 7. According to an exemplary embodiment,shaft600 may consist oftube602 and drivemember604.
• By providingtube602 with a single piece construction, ashaft600 may be advantageously provided that minimizes movement of an end effector during actuation of the end effector, such as indirections230,232 discussed above in regard toFIG. 2. Further, althoughshaft600 may lack stiffening wires, which may be made out of a material that has a relatively high stiffness, such as a metal,shaft600 has a sufficient overall stiffness that is more easily controlled and more uniform from one shaft to another in comparison to shafts including stiffening wires.
• As noted above, materials for a shaft may be selected to affect the stiffness of a shaft. According to an exemplary embodiment,inner tube404 andouter tube402 ofFIG. 5;inner tube504,outer tube502, andribs510 ofFIG. 6; andtube602 ofFIG. 7 may be made of PEEK. With regard to the exemplary embodiments ofFIGS. 6 and 7, the single piece constructions provided byinner tube504,outer tube502, andribs510 inFIG. 6 and the single piece construction provided bytube602 inFIG. 7 may be provided by a single piece comprising PEEK. PEEK may be selected as the material to form the tubes of these exemplary embodiments because of its desirable stiffness values and biocompatibility. For instance, PEEK may be selected instead of FEP for these embodiments because FEP is more compliant and deformable, which could lead to movement of an end effector, such as indirections230,232 discussed above in regard toFIG. 2, if the FEP deformed.
• According to an exemplary embodiment, PEEK may be in an annealed condition. Further, PEEK may be unfilled, according to an exemplary embodiment. Unfilled PEEK may have a tensile modulus of, for example, about 535,000 psi to about 545,000 psi. According to another exemplary embodiment, PEEK may include one or more fillers, such as, for example, glass fiber reinforcement or carbon fiber reinforcement. PEEK that includes a glass fiber reinforcement filler may have a tensile modulus of, for example, about 1,650,000 psi to about 1,750,000 psi. PEEK that includes a carbon fiber reinforcement filler may have a tensile modulus of, for example, about 3,600,000 psi to about 3,950,000 psi. PEEK may be available from Victrex® PLC of Lancashire UK. Exemplary commercial grades of unfilled PEEK available from Victrex® PLC include PEEK 90G, PEEK 151G, PEEK 151G, PEEK 381G, PEEK 450G, and PEEK 450G903. Exemplary commercial grades of filled PEEK available from Victrex® PLC include PEEK 90GL30, PEEK 150GL30, PEEK 450GL30, PEEK 90CA30, PEEK 150CA30, PEEK 90CA30, PEEK 150CA30, PEEK 450CA30, and PEEK 90HMF20. According to an embodiment, the material used for a shaft may include a material to increase the lubricity of the shaft. For instance, the material of the shaft may include, for example, about 5% to about 10% of PTFE and/or perfluoropolyether (PFPE). The addition of the material to increase lubricity of a shaft may advantageously avoid the need for an additional sheath to be placed over an exterior surface of the shaft to lower the coefficient of friction of the outer surface to minimize friction and wear.
• Other materials may be used for the exemplary embodiments ofFIGS. 5-7. Other materials include, for example, acetal, nylon, polyester, and sulfone plastics. Materials selected for the exemplary embodiments ofFIGS. 5-7 may be selected to provide a shaft of a surgical instrument with a desired stiffness. In another example, materials may be selected that are weldable to other components of a surgical instrument. Further, the materials may be selected to minimize damage and wear to an instrument shaft. For instance, material(s) may be selected so that an instrument exhibits substantially no damage after applying 2 lbf to a distal tip of the instrument in a direction normal to a roll axis of the instrument.
• According to an exemplary embodiment, a shaft of a surgical instrument lacking stiffening wires, such as according to the exemplary embodiments ofFIGS. 5-10, may be configured to have an axial stiffness ranging from about 900 lbs/in to about 1250 lbs/in and a bending stiffness ranging from about 50 lbs*in²to about 65 lbs*in², according to calculations. In contrast, a shaft configured according to the exemplary embodiment ofFIG. 4 to include stiffening wires, may have an axial stiffness ranging from about 400 to about 5000 lb/in and a bending stiffness ranging from about 20 to about 500 lbs*in², depending on the stiffening wire to tube interface. Although the maximum calculated stiffness for shafts lacking stiffening wires is lower, this stiffness is not only sufficient but is also advantageously more uniform and consistent from one shaft to another.
• According to an exemplary embodiment, a shaft of a surgical instrument may be configured so that a force required to advance or withdraw the instrument through a cannula is no more than 5 lbf. Turning toFIG. 11, an exemplary embodiment of a surgical instrument is shown inserted within acurved cannula1000 so thatshaft1012 of the instrument has reached maximum insertion. When advanced to maximum insertion, adistal end1014 ofinstrument shaft1012 may extend adistance1016 beyond adistal end1010 ofcannula1000 ranging, for example, from about 5 inches to about 11 inches.FIG. 12 shows an exemplary embodiment of theinstrument shaft1012 withdrawn to a minimum insertion withincannula1000. A minimum insertion distance between adistal end1014 ofinstrument shaft1012 and adistal end1010 ofcannula1000 may range, for example, from about 0.125 inches to about 0.250 inches. According to an exemplary embodiment, a shaft of a surgical instrument may be configured so that no more than about 2.5 lbf is required to advance an instrument from a minimum insertion distance to a maximum insertion distance within a curved cannula.
• The stiffness of a shaft of a surgical instrument may be evaluated, for example, by measuring movement of an end effector when the end effector is actuated. For instance, when an instrument has been advanced to the maximum insertion position shown in the exemplary embodiment ofFIG. 11, a weight may be hung from thedistal end1014 of theshaft1012 and adeflection1004 of theshaft1012 relative to alongitudinal axis1002 of thecannula1000 may be determined. According to an exemplary embodiment, when a one pound weight is hung from thedistal end1014 ofshaft1012, amaximum deflection1004 of about 1.5 inches occurs relative to thelongitudinal axis1002 ofcannula1000.
• As discussed above, a shaft of a surgical instrument may be provided by a single piece tube, as discussed in the exemplary embodiments ofFIGS. 6 and 7. However, it may be advantageous to provide a shaft with a sheath on an outer surface of the tube. For instance, providing a sheath on the outer surface of a tube may advantageously provide a lower coefficient of friction, which reduces friction and wear when advancing and withdrawing an instrument through a cannula. According to an exemplary embodiment, a sheath may be made of a material having a lower coefficient of friction than a tube material that the sheath is located upon. A sheath may comprise, for example, ETFE or other sheath materials used in the art.
• Turning toFIG. 8, an exemplary embodiment of ashaft700 is shown that includes anouter tube702 and aninner tube704 that forms alumen707 for adrive member706.Shaft700 may be formed according to the exemplary embodiment ofFIG. 5, except that asheath710 is provided on anouter surface709 ofouter tube702. According to an exemplary embodiment,outer surface709 may form an outer surface ofshaft700, withsheath710 provided onouter surface709. As shown in the exemplary embodiment ofFIG. 9, ashaft800 may include anouter tube802, aninner tube804 that forms alumen807 for adrive member806, one ormore lumens808, andribs810.Shaft800 may be formed according to the exemplary embodiment ofFIG. 6, except that asheath820 is provided on anouter surface803 ofouter tube802. According to an exemplary embodiment,outer surface803 may form an outer surface ofshaft800, withsheath820 provided onouter surface803. Turning toFIG. 10, an exemplary embodiment of ashaft900 is shown that includes asingle tube902 that forms alumen901 for adrive member904.Shaft900 may be formed according to the exemplary embodiment ofFIG. 7, except that asheath910 is provided on anouter surface903 oftube902. According to an exemplary embodiment,outer surface903 may form an outer surface ofshaft900, withsheath910 provided onouter surface903.
• According to an exemplary embodiment, when a shaft of a surgical instrument is provided with a sheath, such as in the exemplary embodiments ofFIGS. 8-10, dimensions of the shaft may be redesigned to accommodate the sheath. For instance, the outer diameter of the shaft may remain the same whether a sheath is present or absent so that the stiffness of the shaft is maximized while permitting the shaft to fit through a cannula. Therefore, if a sheath is provided, the dimensions of the tube and other components of the shaft may be reduced. For instance, in the exemplary embodiment ofFIG. 5, the radial thickness ofouter tube402 and/orinner tube404 may be reduced. In another instance, in the exemplary embodiment ofFIG. 6, at least one of the radial thickness ofinner tube504, the radial thickness ofouter tube502, and the length ofribs510 may be reduced. In another instance, in the exemplary embodiment ofFIG. 7, the radial thickness oftube602 may be reduced.
• Although the exemplary embodiments ofFIGS. 4-7 show shafts having a substantially smooth outer surface, shafts may have other surface configurations. Turning toFIG. 13, a cross-sectional view of an exemplary embodiment of ashaft1100 is shown that includes a plurality ofprojections1102 on theouter surface1104 ofshaft1100.Shaft1100 may include adrive member1110 connecting a force transmission mechanism to an end effector of the surgical instrument, as discussed in the exemplary embodiments ofFIGS. 1 and 2. Further,shaft1100 may be constructed according to any of the exemplary embodiments ofFIGS. 5-7. As shown in the exemplary embodiment ofFIG. 13,projections1102 may extend a non-zero distance along aradial direction1106 fromouter surface1104. By providingprojections1102, the amount of contact area betweenshaft1100 and an inner surface of a curved cannula may be reduced, which advantageously reduces friction and wear. According to an exemplary embodiment,projections1102 may be sufficient to reduce friction to a degree thatshaft1100 does not require a sheath to minimize friction and wear. Further,projections1102 are not limited to what is shown in the exemplary embodiment ofFIG. 13. For instance,projections1102 may be provided in fewer or greater numbers, be spaced closer or further apart in a uniform or non-uniform spacing, and/or may have different shapes.
• By providing a surgical instrument according to the exemplary embodiments discussed above, a surgical instrument may be advantageously provided that is simpler to manufacture, less costly to manufacture, and provides enhanced properties. For instance, a shaft of the surgical instrument may minimize movement of an end effector during actuation of the end effector, such as indirections230,232 discussed above in regard toFIG. 2. Further, although the shaft may lack stiffening wires made of a material having a relatively high stiffness, the shaft has a sufficient overall stiffness that is more easily controlled and more uniform from one shaft to another in comparison to shafts that include stiffening wires.
• Further modifications and alternative embodiments will be apparent to those of ordinary skill in the art in view of the disclosure herein. For example, the systems and the methods may include additional components or steps that were omitted from the diagrams and description for clarity of operation. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the present teachings. It is to be understood that the various embodiments shown and described herein are to be taken as exemplary. Elements and materials, and arrangements of those elements and materials, may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the present teachings may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of the description herein. Changes may be made in the elements described herein without departing from the spirit and scope of the present teachings and following claims.
• In this description, an actively flexible piece may be bent by using forces inherently associated with the piece itself. For example, one or more tendons may be routed lengthwise along the piece and offset from the piece's longitudinal axis, so that tension on the one or more tendons causes the piece to bend. Other ways of actively bending an actively flexible piece include, without limitation, the use of pneumatic or hydraulic power, gears, electroactive polymer, and the like. A passively flexible piece is bent by using a force external to the piece. An example of a passively flexible piece with inherent stiffness is a plastic rod or a resilient rubber tube. An actively flexible piece, when not actuated by its inherently associated forces, may be passively flexible. A single component may be made of one or more actively and passively flexible portions in series.
• This description's terminology is not intended to limit the invention. For example, spatially relative terms—such as “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like—may be used to describe one element's or feature's relationship to another element or feature as illustrated in the figures. These spatially relative terms are intended to encompass different positions (i.e., locations) and orientations (i.e., rotational placements) of a device in use or operation in addition to the position and orientation shown in the figures. For example, if a device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be “above” or “over” the other elements or features. Thus, the exemplary term “below” can encompass both positions and orientations of above and below. A device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
• It is to be understood that the particular examples and embodiments set forth herein are non-limiting, and modifications to structure, dimensions, materials, and methodologies may be made without departing from the scope of the present teachings.
• Other embodiments in accordance with the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims.

Claims (22)

What is claimed is:

1. A surgical instrument, comprising:

a shaft having a proximal end and a distal end;

a force transmission mechanism coupled to the proximal end of the shaft; and

an end effector coupled to the distal end of the shaft;

wherein the shaft includes a body having an outer surface and an inner surface, the inner surface surrounding a lumen configured to receive a drive member that extends through the lumen;

wherein the outer surface of the body forms an outer surface of the shaft;

wherein the body is made of a single material from the inner surface of the body to the outer surface of the body.

2. The instrument ofclaim 1, wherein the body comprises an inner tube and an outer tube.

3. The instrument ofclaim 2, wherein the body further comprises a plurality of ribs connecting the inner tube and the outer tube.

4. The instrument ofclaim 3, wherein the body further comprises a second lumen and a conduit extending through the second lumen.

5. The instrument ofclaim 2, wherein the inner tube and the outer tube are in contact with one another and are configured to slide relative to one another along an axial direction of the shaft.

6. The instrument ofclaim 2, wherein the body is continuously solid between the outer surface and inner surface of the body.

7. The instrument ofclaim 2, wherein the outer surface of the body is exposed to a surrounding environment.

8. The instrument ofclaim 2, wherein an inner surface of the outer tube and an outer surface of the inner tube have substantially the same radius of curvature.

9. The instrument ofclaim 2, further comprising a sheath located on the outer surface of the shaft.

10. The instrument ofclaim 1, wherein the body consists of a single tube.

11. The instrument ofclaim 1, wherein the single tube is a solid tube between the inner surface and the outer surface.

12. The instrument ofclaim 1, further comprising a sheath located on the outer surface of the shaft.

13. The instrument ofclaim 1, wherein the outer surface of the body has a substantially circular cross-section.

14. The instrument ofclaim 1, further comprising a plurality of projections on the outer surface.

15. The instrument ofclaim 1, further comprising the drive member, which extends through the lumen from the force transmission mechanism to the end effector, wherein the inner surface of the body contacts the drive member.

16. The instrument ofclaim 1, wherein the lumen formed by the inner surface of the body has a diameter ranging from about 0.030″ to about 0.050″.

17. The instrument ofclaim 1, wherein the instrument is a surgical instrument for a teleoperated surgical system.

18. A surgical instrument, comprising:

a shaft having a proximal end and a distal end;

a force transmission mechanism coupled to the proximal end of the shaft; and

an end effector coupled to the distal end of the shaft;

wherein the shaft includes a body having an outer surface that forms an outer surface of the shaft and an inner surface that defines a lumen that a drive member extends through;

wherein the body has a single piece construction.

19. A method of manufacturing a shaft for a surgical instrument, comprising:

extruding a material to form a body of a shaft, wherein the body has an outer surface and an inner surface that forms a lumen configured to receive a drive member that extends through the lumen;

wherein the outer surface of the body forms an outer surface of the shaft; and

wherein the body is made of a single material from the inner surface of the body to the outer surface of the body.

20. The method ofclaim 19, wherein the body is continuously solid from the inner surface of the body to the outer surface of the body.

21. The method ofclaim 19, wherein the body comprises an inner tube and an outer tube.

22. The method ofclaim 21, wherein the body further comprises a plurality of ribs connecting the inner tube and the outer tube.

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