US20030023260A1 - Method and apparatus for dissecting tissue layers - Google Patents

Abstract

A retractor for use in arthroscopic surgery. The retractor has a mechanical expanding portion for expanding against sub-surface tissues when the retractor is in use. The retractor also has a fluid-operated expanding portion, which may be independently controllable, for expanding against sub-surface tissues when the retractor is in use. The retractor is inserted through a small percutaneous opening, expanded in sub-surface tissues without significantly damaging the tissue, then collapsed after use for removal. The retractor can be manipulated to allow the surgeon to push or pull or lever on tissue. The retractor can be hollow like a cannula to permit the passage of one or more surgical devices through the retractor, with a side portal into the center of the retractor.

Description

RELATED APPLICATIONS
• This application is a divisional of co-pending application Ser. No. 08/225,952, filed Jan. 6, 1999 which is a continuation of co-pending application Ser. No. 08/937,940, filed Sep. 25, 1997, which is a continuation of co-pending application Ser. No. 08/466,784, filed on Jun. 5, 1995, which is a divisional of application Ser. No. 08/029,695, U.S. Pat. No. 5,345,927, filed on Mar. 11, 1993, which is a divisional of application Ser. No. 07/631,740, U.S. Pat. No. 5,197,971, filed on Dec. 18, 1990, which is a continuation-in-part of application Ser. No. 07/609,341, filed on Nov. 5, 1990, which is a continuation-in-part application of Ser. No. 07/487,645, U.S. Pat. No. 5,331,975, filed on Mar. 2, 1990.[0001]
BACKGROUND OF THE INVENTION
• The present invention relates to expandable subsurface devices for use in surgery. More particularly, the present invention relates to selectively expandable retractors for use in selectively and specifically moving sub-surface tissue in arthroscopic surgery, endoscopic surgery and fiber optic surgery. (The term “arthroscopic surgery” as used in this application includes endoscopic surgery, fiber optic surgery, and any other type of surgery on sub-surface tissues. Such surgery is performed percutaneously through a small incision or opening in the skin, as opposed to open surgery in which the surgeon cuts through and opens up all superior tissue until all the operating area is exposed.)[0002]
• Arthroscopic surgery is currently performed without suitable tools for specifically moving tissue and creating visualization and working spaces. Generalized expansion is obtained with CO[0003]₂, H₂O, etc. However, this technique leaves fluid everywhere and is not useful to specifically move tissue.
• There are no devices available which allow a surgeon to selectively position various tissue masses encountered during arthroscopic surgery. Delicate tissue such as nerve tissue or blood vessels is put at risk and can be damaged during an operation. Furthermore, the limited space available for the surgeon to work in could make an operation more difficult than it could be.[0004]
• Retractors designed for use in open surgery are unusable in arthroscopic surgery. Current bladder devices such as a Foley catheter or those used in percutaneous transluminal coronary angioplasty are not useful to retract tissue in arthroscopic surgery, because they are made of a soft, pliable, flimsy material; they work with relatively low pressure; and they have smooth walls and a large surface area of contact so as not to damage the delicate tissues. Such bladder devices also inflate into a non-specific shape, assuming the shape of whatever surface or object they encounter. They do not expand or retract at or near the tip, are not rigid enough to be insertable within a joint or among muscles, tendons and bones, and are too flexible to permit specific tissue retraction. Bladders can also be perforated during surgery.[0005]
• Such bladder devices also do not provide enough force to move tissue as needed in arthroscopic surgery, mainly because they are designed to dilate an existing stretchable space within the body, such as a blood vessel, and not to create an actual space from a potential space such as in the subacromial bursa or carpal tunnel. In contrast, a great deal more force is needed to selectively move tissues such as muscles, bones, and tendons and expand a potential space therein. One must have a strong, sufficiently rigid instrument to do this, and exert much more force and yet protect delicate tissues. One also needs the ability to specifically direct force in specific locations or directions, not merely randomly. A bladder such as a Foley catheter would deform in an uncontrolled fashion, not pushing where it is needed most.[0006]
• Accordingly, there exists a need for instruments suitable to mechanically specifically move tissue, which are small enough to fit through a small opening in the skin and which expand to create a working and visualization space in sub-surface tissues. Such instruments must be strong enough and precise enough for use in arthroscopic surgery. My co-pending applications identified above disclose devices suitable for such applications. This application is based on those applications and devices.[0007]
SUMMARY OF THE INVENTION
• The present invention is a mechanically and pneumatically expandable retractor suitable for arthroscopic surgery and removable thereafter without significantly damaging the moved or retracted tissue. The retractor has a distal end and a proximal end. The retractor includes a mechanical expanding portion for expanding against sub-surface tissues when the retractor is in use, and a fluid-operated expanding portion for expanding against sub-surface tissues when the retractor is in use. The fluid-operated expanding portion can be axially co-extensive with the mechanical expanding portion of the retractor, or it can be placed elsewhere along the length or at the tip of the retractor. The fluid-operated expanding portion can expand either independently of or in conjunction with the mechanical expanding portion of the retractor.[0008]
• The retractor preferably has a rigid shaft to allow the surgeon to apply force to sub-surface tissues by pulling or pushing on the retractor, or by using it as a lever. Alternatively, the shaft can be flexible, allowing the retractor to be positioned around a curve or corner and allowing the surgeon to pull back on the retractor to move tissue thereby.[0009]
• In an alternative embodiment, the bladder is not fluid-expanded, but rather covers the mechanical expanding portion to separate it from tissues it contacts.[0010]
• The retractor may have one or more central passages to function as a cannula. Alternatively, the retractor can be solid or needle-like with or without a removable trocar.[0011]
• The retractor is contracted after use and removed from the body tissues without having significantly damaged the tissues.[0012]
• The retractor provides the surgeon with the ability to selectively move or retract tissue and to expand a specific space, and to gain a visualization and working space, a function which is not available in present operating instruments.[0013]
BRIEF DESCRIPTION OF THE DRAWINGS
• Further features of the present invention will become apparent to those skilled in the art to which the present invention relates from reading the following specification with reference to the accompanying drawings, in which:[0014]
• FIG. 1 is a view of a cannula type retractor in accordance with the present invention, having a plurality of expanding arms, shown in an unexpanded condition;[0015]
• FIG. 2 illustrates the retractor of FIG. 1 in an expanded condition;[0016]
• FIG. 3 is a side elevational view of the body of the retractor of FIG. 1;[0017]
• FIG. 4 is a longitudinal sectional view of the nut of the retractor of FIG. 1;[0018]
• FIG. 5 is a side elevational view of the sleeve of the retractor of FIG. 1;[0019]
• FIG. 6 is a series of views illustrating the retractor of FIG. 1 and similar retractors in an expanded condition;[0020]
• FIG. 7 is a view of a retractor having two axially spaced expanding portions, shown in an unexpanded condition;[0021]
• FIG. 8 illustrates the retractor of FIG. 7 in an expanded condition;[0022]
• FIG. 9 is a view of a retractor in accordance with the present invention, and also having an expandable bladder, shown in an unexpanded condition;[0023]
• FIG. 10 illustrates the retractor of FIG. 11 in an expanded condition;[0024]
• FIG. 11 is a view showing a retractor being used in carpal tunnel surgery, in an unexpanded condition;[0025]
• FIG. 12 is a simplified transverse sectional view of the operating area of FIG. 11;[0026]
• FIG. 13 is a view similar to FIG. 11 with the retractor in an expanded condition;[0027]
• FIG. 14 is a simplified transverse sectional view of the operating area of FIG. 13;[0028]
• FIG. 15 is a view of a non-cannula type retractor in accordance with the present invention, shown in an unexpanded condition;[0029]
• FIG. 16 illustrates the retractor of FIG. 15 in an expanded condition;[0030]
• FIG. 17 is an illustration of the use of a pair of retractors in arthroscopic shoulder surgery, with the retractors shown in an unexpanded condition;[0031]
• FIG. 18 is an illustration similar to FIG. 17 with the retractors shown in an expanded condition;[0032]
• FIG. 19 is a view of an elliptically shaped mechanical retractor, in an unexpanded condition;[0033]
• FIG. 20 shows the retractor of FIG. 19 in an expanded condition;[0034]
• FIG. 21 is an end view of the retractor of FIG. 20;[0035]
• FIG. 22 is a view of a mechanical retractor with an independently operable pneumatic bladder retractor, both at the distal end, in an unexpanded condition;[0036]
• FIG. 23 shows the retractor of FIG. 22 in an expanded condition;[0037]
• FIG. 24 is an end view of the retractor of FIG. 20;[0038]
• FIG. 25 illustrates a retractor having a pair of axially spaced expanding portions each being mechanically and pneumatically expandable;[0039]
• FIG. 26 is an end view of the retractor of FIG. 25;[0040]
• FIG. 27 is a view of a mechanical retractor with an independently operable pneumatic bladder retractor at a separate axial location, in an unexpanded condition;[0041]
• FIG. 28 shows the retractor of FIG. 27 in an expanded condition;[0042]
• FIG. 29 is a view of a mechanical retractor with an independently operable pneumatic bladder retractor disposed therein, in an unexpanded condition;[0043]
• FIG. 30 shows the retractor of FIG. 29 in an expanded condition;[0044]
• FIG. 31 illustrates a variety of shapes for the pneumatically expandable retractor portion;[0045]
• FIG. 32 is a view of a mechanical retractor having a pneumatic bladder as the motive force for expansion, in an unexpanded condition;[0046]
• FIG. 33 shows the retractor of FIG. 32 in an expanded condition;[0047]
• FIG. 34 is a view of another mechanical retractor having a pneumatic bladder as the motive force for expansion, in an unexpanded condition;[0048]
• FIG. 35 shows the retractor of FIG. 34 in an expanded condition;[0049]
• FIG. 36 is a view of mechanical retractor for separating tissue having a pneumatic bladder as the motive force for expansion, in an unexpanded condition;[0050]
• FIG. 37 shows the retractor of FIG. 36 in an expanded condition;[0051]
• FIG. 38 is a view of a pneumatic bladder retractor with mechanical arms, in an unexpanded condition;[0052]
• FIG. 39 shows the retractor of FIG. 38 in an expanded condition;[0053]
• FIG. 40 illustrates a mechanical retractor with a non-pneumatic bladder secured to a mechanical expanding portion, in an unexpanded condition;[0054]
• FIG. 41 shows the retractor of FIG. 40 in an expanded condition;[0055]
• FIG. 42 illustrates another mechanical retractor with a non-pneumatic bladder secured to a mechanical expanding portion, in an unexpanded condition;[0056]
• FIG. 43 shows the retractor of FIG. 42 in an expanded condition;[0057]
• FIG. 44 illustrates a mechanical retractor with a mesh-type non-pneumatic bladder secured to a mechanical expanding portion, in an unexpanded condition;[0058]
• FIG. 45 shows the retractor of FIG. 44 in an expanded condition;[0059]
• FIG. 46 is a top plan view of an apparatus for guiding an arthroscope and a cutting device; and[0060]
• FIG. 47 is a longitudinal sectional view of the apparatus of FIG. 46.[0061]
DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
• By way of example, FIGS.[0062]1-5 illustrate anarthroscopic retractor10 in accordance with the present invention. Theretractor10 includes aretractor body12, aretractor sleeve14 and anut16.
• The hollow tubular retractor body[0063]12 (FIG. 3) includes acentral portion18, a wideneddistal end portion20, and a threadedproximal end portion22. Thedistal end portion20 is of a larger diameter than the remainder of theretractor body12. A pair of diametricallyopposed notches24, only one of which is seen in FIG. 3, are formed in thedistal end portion20. Acentral passage26 extends longitudinally the entire length of theretractor body12. Thepassage26 is large enough for arthroscopic surgical instruments to pass through. Thecentral portion18 is rigid to allow manipulation of the distal end portion by moving the proximal end portion. Alternatively, the central portion could be flexible for easier positioning in the body. The threaded proximal end portion also includes suitable means (not shown) such as a clamp to hook up arthroscopic instruments, or to lock theretractor10 on to such a device.
• The nut[0064]16 (FIG. 4) includes abody portion30 having a threadedbore32 for receiving the threadedend portion22 of theretractor body12. Thenut14 is enlarged to form a pair ofhandles34 which extend from thebody portion30 of thenut16. Thehandles34 can be grasped by a surgeon to rotate thenut16, and to manipulate theretractor10 as a whole. Anannular slot36 is formed in the distal end portion of thenut16.
• The hollow tubular retractor sleeve[0065]14 (FIG. 5) includes acentral portion40, aproximal end portion42, and adistal end portion44. Theproximal end portion42 has an oblong widenedportion46 which is received in theslot36 in thenut16. Thedistal end portion44 has a pair of diametricallyopposed projections48, only one of which is shown in FIG. 5. Theprojections48 are received in thenotches24 in thedistal end portion20 of theretractor body12. Acentral passage50 extends longitudinally through the entire length of theretractor sleeve14. Thepassage50 is sized to receive thecentral portion18 and theproximal end portion22 of theretractor body12. Thecentral portion40 is rigid to allow manipulation of the distal end portion by moving the proximal end portion. Alternatively, the central portion could be flexible for easier positioning in the body.
• The[0066]retractor sleeve14 also includes an expandingportion60. The expandingportion60 includes a plurality of circumferentially spaced expandingarms62.Adjacent arms62 define between them a series ofslots64. The expandingportion60 illustrated in the embodiment of FIGS.1-5 has eight equally spacedarms62 over a 360° range. It should be understood that the present invention contemplates that any different number of arms can be used, and they can be spread equally or unequally over a different circumferential extent, in order to provide varying or eccentric expansion.
• Each expanding[0067]arm62 extends between agroove66 adjacent thedistal end portion44 of thesleeve14, and agroove68 adjacent thecentral portion40 of thesleeve14. Thegrooves66 and68 are formed on the exterior of the material of the sleeve. Anintermediate groove70 is formed on the interior of eacharm62 and divides eacharm62 into a distal expandingportion72 and a proximal expandingportion74. Thegrooves66,68, and70 weaken the material of thesleeve14. When force is directed axially on thedistal end portion44 of thesleeve14 in a direction toward the proximal end portion, the material of thesleeve14 buckles at the weakened areas of thegrooves66,68, and70, causing thearms62 to expand radially outwardly.
• To assemble the[0068]retractor10, thehollow sleeve14 is slid axially over theproximal end portion22 of thebody12. Thedistal end portion44 of thesleeve14 engages the wideneddistal end portion20 on thebody12. Theprojections48 on thesleeve14 engage thenotches24 on thebody12, blocking rotation of thesleeve14 relative to thebody12. (Other structures can be used to obtain this blocking function. For example, if the retractor parts are injection molded, a key and keyway structure may be used for ease of manufacture.) At least a portion of the threadedproximal end portion22 of thebody12 is exposed. Thenut16 is threaded onto the exposedproximal end portion22 of thebody12. The widenedportion46 of thesleeve14 is received in theslot36 in thenut16.
• To operate the[0069]retractor10, thenut16 is rotated on the threadedproximal end portion22 of thebody12, decreasing the distance between thenut16 and thedistal end portion20 of thebody12. Thesleeve14 is compressed axially. Thesleeve14 buckles at thegrooves66,68, and70. Thearms62 on thesleeve14 move radially outwardly from an unexpanded condition as shown in FIG. 1 to an expanded condition as shown in FIG. 2. (Any system for shortening the sleeve other than a threaded system can be used also.)
• The radially[0070]outermost surface78 of each expandedarm62, which is the radially outermost point of theretractor10, is located axially at the distal end of theretractor10. Because theretractor10 expands at its distal end, not at a mid-portion, stability is increased, since the surgeon is holding theretractor10 at its proximal end and theretractor10 is firmly positioned at its distal end. Also, the expandedretractor10 thus creates a working space where the surgeon needs it, without having to go further down with the instrument as would be necessary if the expanding portion were axially centrally located. Theretractor10 is rigid in a transverse direction, and therefore the surgeon can pull push or lever it to manipulate subcutaneous tissue.
• There are a variety of ways in which the expanding portion of a retractor in accordance with the present invention can be configured for particular surgical applications. In the retractors shown in FIG. 6, the expanding[0071]arms62 are disposed irregularly circumferentially around the retractor to provide an increased working space or operating area between particular pairs of expandingarms62. The external shape of the retractor when expanded, and the amount of expansion, are designed for the specific application on which that retractor is to be used. For example, if the surgeon is working against bone, he can select a retractor which is configured so that it stays flat against the bone, and expands away in the opposite direction, to push tissue away from the bone and create a working and visualization space next to the surface of the bone.
• The retractor of the present invention, therefore, is not merely a round structure which expands. It allows mechanical manipulation of tissue, a function which is not available now in arthroscopic surgery. It can be in the shape of an umbrella; oval; wedge; cone; triangular; I-beam; a half-moon shape to protect a nerve; a V-shape to push a nerve in a different direction; a V-shape which expands at the tip; T-shaped or L-shaped; or other shapes as desired.[0072]
• As an example, the[0073]retractor10a(FIG. 6) includes asleeve14asimilar to thesleeve14 of theretractor10, but with one less expanding arm. An enlarged workingspace81 is formed between thearm82 and thearm84 of thesleeve14a. A greater portion of the retractor bodycentral portion18 is thus exposed.
• Similarly, the[0074]retractor10bincludes asleeve14bhaving six expanding arms. A larger workingspace85 is created between thearms86 and88, exposing a larger portion of the bodycentral portion18. In theretractor10c, thesleeve14chas only five radially expanding arms, creating a 180° workingspace89 between thearms90 and92.
• In the[0075]retractor10d, six expanding arms are spaced circumferentially around thesleeve14dto expose the retractor bodycentral portion18 on opposite sides. A workingspace93 is created between thearms94 and96 on one side, and a workingspace97 is created between thearms98 and100 on the opposite side. In theretractor10e, only four expanding arms are present, and even larger working spaces are created on opposite sides, that is, aspace101 between thearms102 and104 on one side, and aspace105 between thearms106 and108 on the opposite side.
• It can thus be seen that the[0076]retractor10 can be configured to meet almost any application, by appropriately locating and sizing and configuring the expanding portion of thesleeve14 of the retractor. For example, there may be provided longer expanding arms to provide for a greater amount of expansion. The arms may in such a case may be made thicker for greater strength. All such configurations are included within the scope of the present invention.
• Also included are structures functionally equivalent to the expanding arm construct. For example, the expanding portion of a retractor in accordance with the present invention may be as simple as an expansion device like a screw jack or an inflatable bladder disposed between two opposed plates which spread apart upon actuation of the expansion device. A cable can be used to pull on a part to cause expansion. Or, a cam-operated mechanism can be used with a sliding or rotating part to cause expansion.[0077]
• The[0078]central passage26 through the body portion of theretractor10 effectively allows theretractor10 to serve as a cannula through which surgical instruments can be passed even when the retractor is in use. If a side portal is provided in the retractor as described below, surgical instruments, tools, fluid lines, etc. can be passed into or out of the retractor through the side portal.
• Another important feature of the retractors of the present invention is that they can be contracted after use of the retractor to allow the retractor to be removed from the operating area. The structure of the retractor allows for safe decompression (contraction) and removal of the device after use. For example, in the retractor illustrated in FIGS.[0079]1-5, the widenedportion46 of theretractor sleeve14 is received in theslot36 in thenut14. After expansion of the sleeve as described above, when thenut14 is rotated back so as to move away from thedistal end portion20 of theretractor body12, thenut14 pulls the widenedportion46 of thesleeve14, lengthening the sleeve and causing thearms62 to contract to their starting (unexpanded) position. Theretractor10 can then be removed easily from the operating site, without having significantly damaged any tissue. This feature is not available with any previous mechanical expanding devices such as expanding bone screws.
• FIGS. 7 and 8 illustrate another embodiment of the invention in which a[0080]retractor110 includes two separate axially spaced expanding portions and also has a side portal through which an arthroscope and/or other arthroscopic surgical instruments may be passed.
• The[0081]retractor110 includes ahollow retractor body112 having adistal end portion114 with atool hole116 and ascope hole118. Anedge120 defines an opening orside portal122 in theretractor body112. Theopening122 communicates with a central passage extending axially through thebody112.
• The hollow[0082]tubular retractor sleeve124 includes anintermediate portion126, a pair of expandingportions128 on either side of theintermediate portion126 and aproximal sleeve portion130. Each expandingportion128 of thesleeve124 includes a plurality ofarms62 similar to the expandingarms62 in the embodiment illustrated in FIGS.1-5. Each circumferentially aligned pair ofarms62 is connected by an intermediate sleeve segment such as thesegments125 and127. In theretractor110, the expandingarms62 are spaced circumferentially about thesleeve14 so that the space between theintermediate segments125 and127, as well as the space betweenadjacent arms62, is aligned with theopening122 in theretractor body112.
• Accordingly, when the[0083]retractor110 is expanded as illustrated in FIG. 8, there is access from the central passage of theretractor body112, through theopening122, and between adjacent intermediate segments and adjacent expanding arms, for the passage of surgical instruments. Furthermore, the pair of expandingportions128 move tissue out of the way at axially spaced locations along theretractor110, to provide a large working area extending longitudinally between the two expandingportions128 of the retractor. In similar fashion, expanding portions like or similar to the expandingportions128 can be placed at selected locations along a retractor in accordance with the present invention, in order to selectively retract tissue for a particular application. Two or more separate retractors can also be used for this function.
• In another embodiment of the invention, an inflatable bladder is included on the mechanically expandable retractor. The bladder can be co-extensive with the expanding portion of the retractor, or it can be spaced apart from the expanding portion of the retractor. The bladder can be used independently or in conjunction with the mechanical retractor.[0084]
• FIGS. 9 and 10 illustrate an embodiment of the invention which includes an inflatable bladder circumscribing the expanding portion of the retractor. A[0085]retractor140 includes asleeve14 with an expandingportion60 including a plurality of expandingarms62. The body portion of theretractor140 has a pointeddistal end142 for easier passage through tissues. Proximal to the threadedportion22 of the retractor body, aportion144 of the retractor includes afluid supply port146. Aninflatable bladder150 is bonded to theretractor sleeve14 at two circumferential, axially spacedlocations152 and154. Appropriate fluid passages are provided in the retractor body and the retractor sleeve to provide fluid communication between thefluid supply port146 and thebladder150. The bladder can be deflated with suction.
• The[0086]bladder150 inflates and expands radially upon the introduction of fluid under pressure into thefluid supply port146. Thebladder150 can be inflated independently of expansion of the expandingportion60 of theretractor140. Alternatively, thebladder150 can be expanded in conjunction with expansion of the expandingportion60 of theretractor140, in which case it may be preferable to have the bladder in the shape of the mechanical retractor.
• The[0087]bladder150 prevents tissue from being caught in between the expandingarms62 to minimize tissue damage when the retractor is in use and to allow for easy contraction and removal of the retractor after use. Thebladder150 insures proper operation of the expandingportion60 by keeping tissues out of its way to provide more uniform retraction. Thebladder150 has a tamponade effect, lessening bleeding in the surrounding tissues. Thebladder150 also spreads the retractive force, lessening the risk to delicate tissues such as nerve tissue.
• An expandable bladder such as the[0088]bladder150 can be provided at other locations along aretractor140. For example, a bladder can be provided at a location spaced apart from any expanding portion of the retractor. Also, a bladder can be provided which spans longitudinally the distance between two expanding portions on a retractor. The bladder can be formed of a fluid tight material in order to maintain fluid pressure and exert greater force against the tissues of the body. The bladder can alternatively be made of a perforate material which allows fluid flow therethrough but which also serves to apply force against the tissue it encounters. The bladder may be reinforced, ribbed, or have a specific molded shape. The bladder may be constructed in accordance with my co-pending application Ser. No. 487,645, filed on Mar. 2, 1990, the disclosure of which is incorporated by reference. For example, the bladder is typically formed on a mandrel which is of a particular shape and which is sized about half way between the unexpanded and the expanded size of the bladder. The bladder may be thicker in some areas to expand less, and thinner in other areas to expand more. The bladder may have ridges or areas of differing degrees of resistance to stretching or flexing. The bladder can be pre-shaped to assume a certain form when expanded. The bladder can have a dual durometer layered construction, with a thin layer for fluid retention overlying a thicker layer for shaping. The bladder can have a bellows-type construction.
• One basic purpose of the bladder on a retractor of the present invention is to maintain a separation between the expanding arms and the tissues they expand against. Therefore, the bladder need not be made of a fluid-tight material if the bladder per se is not to be expandable. If desired, the bladder can merely be a fabric, mesh, film, polymer, or other material extending over the expanding arms and moving radially outwardly with them. Whether the bladder is fluid-tight or not, the material of the bladder can be bonded directly to the arms. The material can be stretchable to expand when the expanding arms move radially outwardly then contract when the arms move back inwardly.[0089]
• Use of only a bladder (without a mechanical retraction device) has the disadvantage that a bladder can be punctured with a surgical knife or cutter and will collapse, losing all the retraction gained upon inflation and possibly compromising the surgery. Because the retractors of the present invention are also mechanical in nature, this possibility is avoided, and secure retraction is provided.[0090]
• FIGS. 11 through 14 illustrate the use of a[0091]retractor160 in accordance with the present invention in carpal tunnel surgery. Theretractor160 is illustrated in FIGS.11 and12 in an unexpanded condition, and in FIGS. 13 and 14 in an expanded condition. Theretractor160 is inserted through anincision190 in the wrist, and underneath the transversecarpal ligament192, adjacent themedian nerve194 of ahand196.
• The[0092]retractor160 includes an expandingportion161 with a plurality of expandingarms62, two of which are spaced about an opening orside portal162 for instrument passage therethrough. An expandingbladder164 is bonded to thesleeve166 of theretractor160. Theretractor160 is secured in aholder170 having a pair ofgrips172 and174. Thegrip172 is fixedly attached to asleeve clamp176 which securely clamps thesleeve166 of theretractor160. Thegrip174 is fixedly attached to aportion178 for engaging a widenedportion180 on thebody portion182 of theretractor160. Thebody portion182 has ascope hole184 and atool hole186 extending therethrough. Suitable locking means can also be provided to lock the retractor in a particular expanded condition.
• FIGS. 13 and 14 illustrate the[0093]retractor160 in an expanded condition. Relative movement of thegrip172 toward thegrip174 draws thebody portion182 proximally relative to the clampedsleeve portion166, expanding the expandingportion161. The expandingarms62 move radially outwardly to create a working oroperating area198 adjacent theligament192. Thebladder164 is also expanded about the expandingportion60 of theretractor160. Tissue is not significantly damaged by theretractor160. After the operation is completed, theretractor160 is simply contracted or collapsed and removed from the operating site.
• Because of the controlled expansion of the[0094]retractor160, themedian nerve194 is shielded from the operating area. Tools and an arthroscope may be passed through theopening162 into theoperating area198, while themedian nerve194 and other tissues such astendons200 are safely shielded from theoperating area198. Accordingly, by use of theretractor160, the surgeon is provided with an enlarged open area in which he can work on theligament192, and at the same time he has protected themedian nerve194 from the operating area. The surgeon has full visualization and working of the entire space, not a limited vision area as with other systems. This type of operation can, of course, be performed also with a mechanically expandable retractor not having a bladder thereon.
• Indicated schematically at[0095]193 in FIG. 11 is means for measuring the retractive force applied by the expanding portion of theretractor160. This can be any suitable apparatus for measuring the force needed to bring together thegrips172 and174, for example. With the retractor of FIGS.1-5, a torque wrench or other instrument can be used to measure the force needed to turn thenut16. Similarly, any known apparatus can be used to monitor the fluid pressure inside an expandable bladder on a retractor of the present invention. Thus, with any of the present retractors, the expansion force can be monitored and controlled.
• FIGS. 15 and 16 illustrate another embodiment of the mechanically expandable retractors in accordance with the present invention. The[0096]retractor210 illustrated in FIGS. 15 and 16 is a non-cannula type retractor. It does not have a central passage extending longitudinally through the retractor, but rather is solid or needle-like. Accordingly, theretractor210 may be made slimmer if desired. It may be desirable to use such a non-canula type retractor in a situation where the surgeon is already employing a cannula through which instruments and/or a scope may be passed. The retractor may have a removable trocar also.
• The[0097]retractor210 may have a pointeddistal end portion212 for easier insertion through tissues. (Alternatively, the retractor may be utilized in conjunction with a removable trocar. The pointed distal end portion would be the distal tip of a removable trocar which would be removed after placement of the expanding portion of the retractor in the desired location.) Theretractor210 has an expandingportion60 with a plurality of expandingarms62.Grooves66,68, and70 in thesleeve14 define thearms62 and provide weakened portions to allow for radial expansion of thearms62. Rotation of thenut16 relative to the threadedproximal end portion22 of the retractor body214, shortens the distance between thenut16 and thedistal end212 of the retractor body. Thesleeve14 is compressed axially, and thearms62 expand radially outwardly.
• The expanding portion of the[0098]retractor210 illustrated in FIGS. 15 and 16 is oriented in the opposite direction longitudinally from the expanding portion of the retractor shown in FIGS.1-5. Thus, the maximum point of expansion is spaced from the distal end of theretractor210. However, this configuration provides anannular end face216 at the proximal end of the expandingportion60. Thus, theretractor210 is usable to pull back on tissue, or to hook tissue to move it proximally. The retractor shown in FIGS.1-5 would in such use slide out because its expanding portion has a conical shape with an apex at its proximal end. This “reversed” design can be revised in practice to place the maximum point of expansion closer to or at the distal end of the retractor.
• FIGS. 17 and 18 illustrate the use of a pair of retractors in accordance with the present invention to perform arthroscopic surgery on the[0099]acromion220 in the shoulder. Thehumeral head222 is spaced from theacromion220, with therotator cuff224 and thebursa226 therebetween. Thebursa226 normally fits tight up against thesurface228 of theacromion220, but is shown spaced therefrom for clarity. Because thebursa226 is normally tight up against thesurface228 of theacromion220, it is difficult to operate on thesurface228 of theacromion220.
• To gain access to the[0100]surface228, a pair ofretractors230 and232 are used. Theretractor230 is inserted through anincision234 in the back236 of the shoulder. Theretractor230 has an expandingportion238 located below the surface of the skin. Theretractor230 has a projectingportion240 located above the surface of the skin. Theretractor230 has apassage242 to allow the passage of surgical instruments therethrough.
• The[0101]retractor232 is inserted through anincision242 in the side of the shoulder. An expandingportion244 of theretractor232 is located below the surface of the skin. A projectingportion246 of theretractor232 is located above or outside of the skin. Theretractor232 has acentral passage248 to allow the passage of an arthroscope therethrough.
• The[0102]retractor230 is inserted through theincision234 until its expandingportion238 engages thesurface228 of theacromion220. The expandingportion238 is irregularly configured so as to stay relatively flat against theacromion220 and expand 180° away to push thebursa226 away from thesurface228. The expandingportion238 is then expanded. Thebursa226, androtator cuff224 are forced away from thesurface228, creating a working andvisualization space250 against thesurface228. Similarly, theretractor232 is inserted through theincision242 until its expandingportion244 engages thesurface228. The expandingportion244 is then expanded. Thebursa226 and therotator cuff224 are forced away from thesurface228, enlarging the working andvisualization space250.
• An arthroscope is then inserted through the[0103]passage248 in theret ractor232 until its distal end is located in thespace250. A shaver is then inserted through thepassage242 in theretractor230, until its distal end is also in the workingspace250. The surgeon thus has both the arthroscope tip and the shaver in a clear volume adjacent the surface to be worked upon. The surgeon can then remove an area ofbone252 from theacromion220, without interference from thebursa226 and therotator cuff224 which are normally tight up against thesurface228.
• The surgeon can manipulate the projecting[0104]portion240 of theretractor230, and the projectingportion246 of theretractor232, to further move the tissues as desired. For example, the surgeon can pull proximally on the projectingportion246 of theretractor232 to pull thebursa226 androtator cuff224 away from thesurface228. The surgeon can use theretractor230 as a lever, moving the projectingportion240 thereof upwardly as viewed in FIG. 18 to move the expandingportion238 relatively downwardly to move thebursa226 and therotator cuff224 away from thesurface228. Tissue is not significantly damaged by theretractor230.
• Upon completion of the operation, the expanding[0105]portion238 of theretractor230 is contracted or collapsed, and theretractor230 is removed from the operating site. The expandingportion244 of theretractor232 is contracted or collapsed, and theretractor232 is removed from the operating site. Thebursa226 and therotator cuff224 regain their original position against theacromion220.
• In accordance with a feature of the present invention, a retractor in accordance with the present invention need not have a round shape as shown in the drawings. Because there is no relative rotation between the retractor body and the retractor sleeve, neither must be round, and the body and sleeve need not have the same cross-sectional configuration. For example, the retractor may have an elliptical or oblong shape if two cannulas or passages are formed therein. The shape may be flattened if a slimmer profile is needed to pass between certain tissue layers. A square cross-section may be provided if desired. This ability to use any shape provides more leeway in configuring the expanding portion of the retractor, because the expanding portion does not have to have a round cross-sectional configuration.[0106]
• In accordance with another feature of the present invention, a retractor can also function as two or more cannulas side-by-side. In those Figures which illustrate a cannula-type retractor having both a tool hole and a scope hole at the distal end, the tool hole and the scope hole are the ends of longitudinally co-extensive passages extending through the retractor body. These passages or lumens serve as two cannulas.[0107]
• As an example of these two features, FIGS.[0108]19-21 illustrate amechanical retractor260 with an elliptical cross-section and a dual-cannula configuration. Theretractor260 has a pair ofpassages262 and264 extending longitudinally through the retractor. Theretractor260 has an expandingportion266 with a plurality of expandingarms268.Grooves270,272, and274 in theretractor sleeve276 define thearms268 and provide weakened portions to allow for radial expansion of thearms268. When thesleeve276 is compressed axially thearms268 expand radially outwardly from the unexpanded condition shown in FIG. 19 to the expanded condition shown in FIG. 20.
• FIGS.[0109]22-24 illustrate an embodiment of the invention in which a plurality of inflatable bladders are located at the distal end portion of a retractor having a mechanical expanding portion. Theretractor280 has asleeve portion282, abody portion284, and anut286 withhandles288 thereon. Theretractor sleeve282 includes a pair of expandingarms290 on one circumferential side of thesleeve282, and a pair of expandingarms292 on the opposite side. Located cirumferentially between thearms290 and thearms292 are a pair of expandingbladders294 and296. Thebladders294 and296 are supplied with fluid under pressure through afluid supply line298. Acentral passage300 extends through theretractor280.
• The[0110]bladders294 and296 may work independently of the mechanical expansion of theretractor280. Thearms290 and292 are expanded by rotation of thenut286 relative to thebody portion284, in a manner as described above. Thebladders294 and296 are inflated upon the introduction of fluid under pressure through thefluid supply line298. Such expansion is controllable independently of the expansion of thearms290 and292. Accordingly, theretractor280 includes both mechanical and pnematic expansion means, which are independently controllable, located at the same axial location along theretractor280. The relative configurations of the bladders and of the mechanical expanding arms can be varied to suit the particular application for which any given retractor is used.
• FIGS. 25 and 26 illustrate a[0111]retractor302 having two expandingportions304 and306 spaced axially apart from each other. Each expandingportion304 and306 includes a plurality of mechanically expandingarms308 of the type described above. A plurality ofinflatable bladder segments210 are interleaved between thearms308. Ascope hole312 and atool hole314 extend through thebody316 of theretractor302 and are accessible through aside portal318. Theside portal318 is accessible through anopening320 between adjacentintermediate sleeve sections322 and324 of theretractor sleeve326. There is no bladder between the mechanical expandingarms308 attached to theintermediate sleeve sections322 and324. Thus, a working area328 (FIG. 26) is created which is accessible to the interior of theretractor302 and from tissue which has been pushed aside upon expansion of theretractor302.
• FIGS. 27 and 28 illustrate a[0112]retractor332 having an inflatable bladder portion spaced axially from a mechanically expandable portion. Theretractor332 includes asleeve334 and abody336. Thesleeve334 has an expandingportion338 and anintermediate portion340. Acircumferentially extending bladder342 is disposed at the distal end of thebody336. Thebladder342 extends most of the way about the circumferential extent of thesleeve334, but does not cover a portion on which is formed aside portal344 in thesleeve334. Thebladder342 is inflatable or expandable independently of the mechanical expandingportion338. Simultaneous expansion of both thebladder342 and the expandingportion338 creates a longitudinally extending working space between them, generally coextensive with theintermediate portion340 of thesleeve334. This working portion can be accessed through theside portal344. It should be noted that, in another configuration, the position of the mechanical expandingportion338 and the pneumatic expandingportion342 can be reversed. It should also be noted that more than two expanding portions can be provided on one retractor. The number, configuration, and placement of the expanding portions can be varied in accordance with the particular application for that retractor.
• FIGS. 29 and 30 illustrate a[0113]retractor350 which includes a separate bladder that slides through the mechanical cannula type retractor and is inflatable where needed at a location spaced apart from an expanding portion on the mechanical retractor. Theretractor350 includes asleeve352, abody354, and anut356. An expandingportion358 is located at the distal end of thesleeve352, and acentral passage360 extends through thecannula type retractor350. A separateinflatable bladder362 is disposed within theretractor350 through anopening364. Thebladder362 includes afluid supply line366 extending through theretractor350. When expanded, thebladder362 includes a widenedportion368 at itsdistal end370, and a narrowerconical portion372 located proximal to thefluid supply line366. Thebladder362 can be expanded simultaneously with the expandingportion358, or can be expanded separately and independently as needed.
• There are a variety of ways in which the pneumatic expanding portion (bladder) of a retractor in accordance with the present invention can be configured for particular surgical applications. The external shape of the bladder when expanded, and the amount of expansion, are designed for the specific application on which that retractor is to be used. For example, the bladder can extend only around a circumferential sector of the retractor, such as[0114]90, to provide an increased working space or operating area.
• Thus, if the surgeon is working against bone, he can select a bladder which is configured so that it stays flat against the bone, and expands away in the opposite direction, to push tissue away from the bone and create a working and visualization space next to the surface of the bone.[0115]
• The bladder is therefore not merely a round structure which expands. It is configured to provide for selective mechanical manipulation of tissue, a function which is not available now in arthroscopic surgery. It can be in the shape of an umbrella; oval; wedge; cone; triangular; I-beam; a half-moon shape to protect a nerve; a V-shape to push a nerve in a different direction; a V-shape which expands at the tip; T-shaped or L-shaped; or other shapes as desired.[0116]
• As an example, a retractor[0117]374 (FIG. 31) includes abladder376 extending part way around the circumference of theretractor body378. Acentral passage380 extends through theretractor body378 so that theretractor374 can function as a cannula. Opposed axially extendingsurfaces382 and384 define a workingspace386 between them.
• Similarly, the[0118]retractor388 includes abladder390 having opposed axially extendingsurfaces392 and394. Alarger working space396 is created between thesurfaces392 and394, exposing a larger portion of thebody portion398. In theretractor400, thebladder402 has axially extendingsurfaces404 and406 which create a 180 workingspace408 between thesurfaces404 and406.
• In the[0119]retractor410, two expandingportions412 and414 are spaced circumferentially to expose theretractor body416 on opposite sides. A workingspace418 is created between the arms bladder surfaces420 and422 on one side, and a workingspace424 is created between the bladder surfaces426 and428 on the opposite side. In theretractor430, the axial orientation of thebladder432 is reversed, so that it expands at itsproximal end434 rather than itsdistal end436. It can thus be seen that the bladder portion of a retractor of the present invention can be configured to meet almost any application greater strength.
• In the retractors illustrated in FIGS. 32 through 37, an expandable bladder provides the motive force to separate two or more relatively rigid mechanical pieces. The mechanical pieces perform the actual tissue retraction.[0120]
• The retractor[0121]440 (FIGS. 32 and 33) includes a pair ofjaws442 and444 pivotally mounted to abody portion446. Anexpandable bladder448 is disposed within theretractor440 between thejaws442 and444. Upon expansion of thebladder448, thejaws442 and444 pivot radially outwardly from the position show in FIG. 32 to the position shown in FIG. 33. This retractor configuration has several advantages. First, thejaws442 and444 expand most at their distal ends, as opposed to the more proximal expansion of the retractor of FIGS.1-5, for example. Second, it can in some instances be easier to shape rigid mechanical pieces such as thejaws442 and444 to fit a particular application, that to shape an inflatable bladder.
• The retractor[0122]450 (FIGS. 34 and 35) includes a pair ofjaws452 and454. Thejaw454 is pivotally mounted to thebody portion456. Anexpandable bladder458 is disposed within theretractor450 between thejaws452 and454. Upon expansion of thebladder458, thejaw454 pivots radially outwardly from the position shown in FIG. 34 to the position shown in FIG. 35. This retractor configuration can be advantageous when it is desired to have expansion occur primarily on only one side of the retractor.
• The retractor[0123]460 (FIGS. 36 and 37) includes a pair ofjaws462 and464. Thejaws462 is fixed to or integral with theretractor body portion466. Thejaw464 is pivotally mounted to the pointeddistal end468 of theretractor460. Anexpandable bladder470 is disposed within theretractor460 between thejaws462 and464. Thebladder470 is secured to the inside of thejaws462 and464. Theretractor460 also includes means (not shown) for providing suction as well as inflation to thebladder470. Upon expansion of thebladder470, the proximal end of the jaw pivots radially outwardly from the position shown in FIG. 36 to the position shown in FIG. 37. Upon the application of suction to thebladder470, thejaw464 pivots radially inwardly back to the closed position shown in FIG. 36.
• The[0124]retractor460 can be used as a wedge to separate tissue layers. Thebladder470 is first expanded to force tissue out of the way. The tissue stays apart for a period of time after being forced open. The bladder is then contracted with suction to bring the retractor to its closed condition. The pointeddistal end468 of theretractor460 is then slid in further, and expanded again. The procedure is repeated as needed. Thus, the bladder is expanded and contracted to move tissue of the way, and the retractor is gradually worked into the tissue to a depth that is required for the specific application.
• In the retractor[0125]472 (FIGS. 38 and 39), aninflatable bladder474 is attached to aninner body portion476 of theretractor472. Thebladder474 is also attached to the insides of a plurality of expandingfingers478. Upon inflation of thebladder474, thefingers478 move radially outwardly to move tissue as desired. The shape and amount of the expansion are controllable by not only the inflation of thebladder474 but also the shape and size of thefingers478. The greatest amount of expansion occurs at the distal end of the retractor.
• On a retractor such as those shown in FIGS. 26 and 26, the bladder functions to separate the mechanical expanding arms and the tissues they expand against. Therefore, the bladder need not be made of a fluid-tight material if the expansion force is to be obtained solely mechanically. The bladder can merely be a fabric, mesh, film, polymer, or other material extending over the expanding arms and moving radially outwardly with them. The material of the bladder can be bonded to the body of the retractor or directly to the arms. The material can be stretchable to expand when the expanding arms move radially outwardly then contract when the arms move back inwardly.[0126]
• These features are illustrated in the retractors shown in FIGS.[0127]40-45. The retractor480 (FIGS.40-41) is configured mechanically like theretractor10 shown in FIGS.1-5. Theretractor480 includes abody portion482, asleeve portion484, and anut486. Thesleeve484 has a plurality of expandingarms488. Acentral passage490 extends through theretractor480 so that theretractor480 functions as a cannula. Abladder492 is bonded at494 and496 to thebody482 and thesleeve484. The retractor498 (FIGS. 42 and 43) is similar except that thebladder500 thereon is bonded only to the expandingarms502. In the retractor510 (FIGS. 44 and 45), thebladder512 thereon is Formed of a fluid-permeable material such as an open-weave mesh-type fabric or other similar material which is biocompatible.
• FIGS. 46 and 47 illustrate a[0128]retractor body portion520 which includes twoparallel passages522 and524. Thelarger passage522 is designed for the passage therethrough of an arthroscope. The smaller passage534 is designed for the passage therethrough of a fiber optic laser cutter or electric cautery device. Thepassage522 has a relatively long portion oropening526, suitable for an arthroscope with a viewing angle of 10 or more. Theend portion528 of thesmaller passage524 extends at an angle to themain portion530, and terminates in a relatively small portal oropening532. Thus, a device inserted through thesmaller passage524 will exit thebody portion520 at an angle to its longitudinal extent.
• This configuration is ideal for the above-described use of a fiber optic laser cutter or electric cautery device in conjunction with an arthroscope. The fiber optic laser cutter will cut at a location directly in front of and in the field of view of the arthroscope. Fiber optic laser cutters are available in sizes as small as 0.6 mm in diameter. The[0129]device520 can be correspondingly small in overall size. If made of plastic material, the device52-electrically insulates the cutting device from the body tissues. Accordingly, the present invention provides structure ideally suited for enhanced arthroscopic cutting. Because the cutting device and the arthroscope are fixed in position relative to each other, theapparatus520 allows direct control of both the arthroscope and the cutting device while controlling the location of the retractor.
• It should be noted that the[0130]apparatus520 illustrated in FIGS. 46 and 47 is suitable for use alone, that is, without the sleeve portion of the retractor. In this manner, the apparatus serves as an inserter or guide for the arthroscope and the cutting or cautery device. The apparatus can be fixed to the arthroscope to enhance stability. The tissue to be operated upon can be retracted with a separate arthroscopic retractor at the work area.
• In each of these retractors, the bladder prevents tissue from being caught in between the mechanical expanding arms. This minimizes tissue damage when the retractor is in use, and allows for easy contraction and removal of the retractor after use. The bladder insures proper operation of the mechanical expanding portion by keeping tissues out of its way to provide more uniform retraction. The bladder also has a tamponade effect lessening bleeding in the surrounding tissues. The bladder also spreads the retractive force, lessening the risk to delicate tissues such as nerve tissue.[0131]
• In accordance with another feature of the present invention, the retractors incorporate a projecting portion at their proximal ends for manipulating the retractor. The projecting portion projects from the surface of the body tissues when the retractor is in use. In FIGS.[0132]1-5, for example, theproximal end portion22 of theretractor body12 and theproximal end portion42 of thesleeve14, along with thenut16, project from the surface of the body tissues when the retractor is in use. Theretractor10, when expanded, can thus be used to pull or push on tissue to move the tissue subcutaneously. Similarly, theretractor160 illustrated in FIGS. 11 through 14 has parts projecting outwardly of theincision190 to allow external manipulation of the sub-surface portion of the retractor.
• This external projecting portion (or handle) is useful in many ways. It allows the surgeon to move tissues at will by pulling or pushing on the retractor or using it as a lever to move tissue subcutaneously. The surgeon can control the working point deep within the tissues because he can control the exposed portion of the retractor. Also, it allows the surgeon to block fluid flow, as an expanded retractor can be pulled back to seal flow and give more room to see and work. The retractor can also free up one hand for the surgeon.[0133]
• These are all features which are available to a surgeon in open surgery, but not in arthroscopic surgery unless using a retractor as described herein. The intermediate portion of the retractor of the present invention is preferably rigid enough to provide for such manipulation and to provide for precise positioning of the expandable portion within the body tissues. Alternatively, the intermediate portion can be flexible or selectively rigidifiable.[0134]
• A retractor in accordance with the present invention is small and light weight, and thus can be packaged under sterile conditions and be disposable to maintain sterility. Current retractors have been constructed which are about 85 mm long, about 7 mm across in an unexpanded condition, and about 26 mm across when expanded. The amount of expansion can be greater or less. The dimensions will vary significantly, of course, with the particular surgical application. For example, the expanding portion can be made smaller in diameter (when unexpanded) than the body portion of the retractor. In percutaneous (fiber optic or endoscopic) abdominal or thoracic surgery, expansion of up to 10 cm or more is needed, to move the stomach or small intestine, the greater omentum, the spleen, or the liver. The number and placement of expanding portions will vary with the application also.[0135]
• Retractors have been constructed of polymers such as nylon, but can be injection molded of other materials also. Retractors can also be constructed of polymers, composites and/or metals such as aluminum. The surface of the material can be pebbled or roughened or ridged, or have serrated edges, to better grip tissue and hold the retractor in position. Of course, the surface must still remain smooth enough so that the retractor is easily removable without damage to the tissue it contacts.[0136]
• The various portions or the retractor can be made of different materials. The bladder, as mentioned, is preferably made of an elastomeric material which is strong enough to move tissue as desired. A suitable material for the[0137]expandable bladder130 is Silastic® elastomer, which is available from Dow Corning in medical grades. The mechanical expanding portion can be made of nylon for light weight and sufficient strength. The shaft can be made of aluminum for rigidity.
• The retractor also need not be straight as shown in the drawings. The retractor can be angled or bent, for example at a 45 or 90 angle, in the intermediate portion. Appropriate means for transmitting force at an angle are provided in such case in order to be able to shorten the sleeve to expand the arms.[0138]
• Any part or all of the retractor can be made of a biodegradable material. For example, the mechanical expanding portion of a retractor can be made of a biodegradable material, and can be made detachable from the remainder of the retractor. Similarly, the expandable bladder can be made of a biodegradable material, and can be made detachable from the remainder of the retractor. In such a case, the biodegradable portion can be detached and left in the body after surgery. This is useful, for example, to prevent adjacent tissue planes from scarring together after surgery. The biodegradable mass will in time disappear, allowing the tissues to adjoin after they are healed.[0139]
• The[0140]expandable portion60 or theexpandable bladder130, or even the entire retractor, can be made of a transparent material to provide a better view of the operating area and improved visualization.
• The amount of expansion of the retractors can be varied. Retractors of the present invention can be constructed which will expand up to 600% or more, and from as little as a few millimeters up to about ten centimeters or more, dependent on the location of use. This range of expansion is unattainable by any other available device.[0141]
• From the above description of the inventions, those skilled in the art will perceive improvements, changes and modifications. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.[0142]

Claims (6)

What is claimed:

1. A method of maintaining separation between first and second tissue layers, comprising the steps of:

a) separating the first tissue layer from the second tissue layer;

b) introducing an inflatable chamber between the first and second tissue layers with the chamber in a collapsed condition, wherein the inflatable chamber includes a first sheet having a first outer periphery and a second sheet having a second outer periphery sealingly attached to the first outer periphery, wherein each of the first outer periphery and the second outer periphery is generally trapezoidal; and

c) inflating the inflatable chamber after the introducing step.

2. The method ofclaim 1, wherein the first outer periphery has a fist edge and a second edge longer than the first edge, and wherein the inflatable chamber includes a throughhole positioned closer to the first edge than the second edge.

3. The method ofclaim 1, wherein the first outer periphery has a first linear edge and a second linear edge longer than the first linear edge, and wherein the inflatable chamber includes a throughhole positioned closer to the first linear edge than to the second linear edge.

4. The method of introducing an instrument into a working space in a patient, comprising the steps of:

a) cutting an incision in the patient;

b) dissecting a first tissue layer from a second tissue layer;

c) inserting an inflatable chamber between the first and second tissue layers, the inflatable chamber having a deflated condition and an inflated condition, the inflatable chamber being inserted between the first and second tissue layers in the deflated condition, the inflatable chamber including a first sheet having a first outer periphery and a second sheet having a second outer periphery sealingly attached to the first outer periphery, wherein the first outer periphery has a first extended portion and a second extended portion defining a space therebetween;

d) inflating the inflatable chamber after the inserting step; and

e) introducing an instrument into the working space through the space between the first extended portion and the second extended portion.

5. A method of maintaining separation between first and second tissue layers, comprising the steps of:

a) separating the first tissue layer from the second tissue layer;

b) introducing an inflatable chamber between the first and second tissue layers with the chamber in a collapsed condition, wherein the inflatable chamber includes a first sheet having a first outer periphery and a second sheet having a second outer periphery sealingly attached to the first outer periphery, wherein each of the first outer periphery and the second outer periphery has three convex portions and a non-convex portion between each pair of the convex portions; and

c) inflating the inflatable chamber after the introducing step.

6. A method of maintaining separation between first and second tissue layers, comprising the steps of:

a) separating the first tissue layer from the second tissue layer;

b) introducing an inflatable chamber between the first and second tissue layers with the chamber in a collapsed condition, wherein the inflatable chamber includes a first sheet having a first outer periphery and a second sheet have a second outer periphery sealingly attached to the first outer periphery, wherein each of the first outer periphery and the second outer periphery is bilaterally symmetrical about an axis, and each of the first outer periphery and the second outer periphery has a first generally triangular wing portion on another side of the axis, wherein the first outer periphery has a first curved edge and a second curved edge longer than the first curved edge, and wherein of the first general triangular wings portion and the second general triangular wing portion has an edge coinciding with a portion of the second curved edge; and

c) inflating the inflatable chamber after the introducing step.

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