US20060247602A1 - Ureteral access sheath - Google Patents

Abstract

A ureteral access sheath adapted for insertion into a urethra includes an elongate tube extending between a proximal end and a distal end. A handle assembly is disposed at the proximal end and includes enlarged portions which inhibit migration of the sheath into the urethra. The enlarged portions are shaped like the bell of a horn with a concave, distally-facing outer surface and a convex, proximally-facing inner surface. The inner surface functions as a funnel while the outer surface is sized and configured to receive adjacent fingers of a user's hand held in its natural position. In an associated method, this shape of the handle assembly facilitates maintaining the sheath in a stationary position during insertion and removal of instrumentation. The handle assembly can be movable on the tube to facilitate variation of the sheath link in situ.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a divisional application of U.S. patent application Ser. No. 10/198,030, filed Jul. 13, 2002, which is a Continuation-in-Part of U.S. patent application Ser. No. 09/303,485, filed Apr. 30, 1999, now U.S. Pat. No. 6,471,684, issued Oct. 29, 2002, the disclosures of which are hereby incorporated by reference as if set in full herein.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• This invention relates generally to guideways for endoluminal access and more specifically to surgical access devices adapted to introduce surgical instrumentation into body conduits.
• 2. Discussion of the Prior Art
• Surgical access devices of the prior art typically include a sheath having an outside diameter and an inside diameter. An obturator or dilator is inserted into the sheath to facilitate introduction of the sheath into the body conduit. Once the sheath is positioned, the obturator is removed leaving a working channel for surgical instrumentation.
• Particularly in the field of urology, the sheath has been provided in the form of an elongate tube having an axis extending between a proximal end and a distal end. The diameter of the tube is generally constant, except for a reduced diameter segment at the distal end. Although the obturator has had an enlarged structure at its proximal end, there has been no such enlargement for the sheath. This has presented a problem as the sheath has tended to migrate distally and disappear beneath the urethral meatus. Representative of this art is the FLEXIBLE URETEROSCOPE SHEATH manufactured and sold by Cook Urological Incorporated.
• Access devices particularly adapted for other body conduits have had enlargements at the proximal end, but these have not been specifically configured to prevent migration or facilitate the introduction of instrumentation. Representative of this art are the “banana peel” sheaths which split axially for removal after catheter placement.
• During the introduction and removal of dilators, obturators, and instrumentation into and out of a sheath, it is always desirable to facilitate maintenance of the sheath in a relatively stationary orientation. In the past, there has been no handle structure which was sized and shaped to accommodate engagement by a user's hand disposed in its natural position with the palm facing the user. Nor has there been any progressive funnel structure which would facilitate the introduction of instrumentation into the working channel of the sheath.
SUMMARY OF THE INVENTION
• These deficiencies of the prior art have been eliminated with the present access device which includes a sheath having at its proximal end a handle specifically adapted to inhibit migration and facilitate use with instrumentation. The handle is formed as a radial enlargement having a distally-facing surface and a proximally-facing surface The distally-facing surface has a generally concave configuration which provides a gradual enlargement inhibiting migration of the sheath into the ureter. The concave configuration is sized to receive adjacent fingers of a user's hand disposed in its natural position, in order to facilitate the stationary orientation of the sheath. The concave, distally-facing surface is continuous around the axis of the sheath so that the advantage of this concave configuration can be appreciated regardless of the radial orientation of the sheath.
• The proximal-facing surface has a generally convex configuration providing for an increased funneling of an instrument as it is inserted into the working channel of the sheath. Both the distally-facing surface and the proximally-facing surface extend radially inwardly with progressively equal distal positions along the sheath. This provides the handle with the general shape of the bell of a horn. This configuration is not only ergonomically comfortable, but highly practical in addressing the problems of migration, as well as instrument insertion and removal.
• The handle can be provided with characteristics permitting the handle to be moved to a preferred position along the tube of the sheath, and then to be fixed to the tube at that preferred location. This makes it possible to provide the sheath with any desired length, even after it has been inserted into the body conduit. A metal structure such as a spring can be molded into the tube of the sheath to facilitate kink resistance.
• The inner dilator can be provided with a Luerlock end, permitting attachment of a sidearm adaptor (not shown). This allows for installation of contrast during sheath placement without the need to remove the guidewire.
• These and other features and advantages of the invention will become more apparent with a description of preferred embodiments and reference to the associated drawings.
DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view illustrating a sheath of the present invention with an obturator or dilator adapted for use with the sheath;
• FIG. 2 is a perspective view illustrating the obturator operatively disposed within the sheath;
• FIG. 3 is an axial cross-section view taken along lines3-3 ofFIG. 2 and illustrating the obturator operatively disposed within a tube and “handle” of the sheath;
• FIG. 4 is an enlarged radial cross-section view of the handle assembly illustrated inFIG. 3;
• FIG. 5 is a side-elevation view of the sheath and obturator operatively disposed in the urethra and illustrating a preferred configuration for the handle assembly of the sheath;
• FIG. 6 is a side-elevation view similar toFIG. 5 of a further embodiment of the handle assembly of the present invention;
• FIG. 7 is a side-elevation view partially in phantom and exploded to illustrate components of another preferred embodiment of the handle assembly providing for sheath length adjustment;
• FIG. 8 is a side-elevation view illustrating the components ofFIG. 7 in an assembled configuration;
• FIG. 9 is a radial cross-section view taken along lines9-9 ofFIG. 8;
• FIG. 10 is a perspective, disassembled view of a further embodiment of a handle assembly permitting length adjustment;
• FIG. 11 is a perspective, assembled view of the components illustrated inFIG. 10; and
• FIG. 12 is a side-elevation view partially in fragment and illustrating a spring embodiment of the tube associated with the sheath of the present invention
DESCRIPTION OF PREFERRED EMBODIMENTS AND BEST MODE OF THE INVENTION
• A ureteral access sheath is illustrated inFIG. 1 and designated generally by thereference numeral10. InFIG. 1, thesheath10 is illustrated in combination with a separate, but associated, dilator orobturator12. Thesheath10 has the general configuration of anelongate tube14 having anaxis16 which extends between aproximal end18 and adistal end21. Ahandle23 is disposed at theproximal end18 of thetube14 and provides access into a workingchannel25 of thetube14.
• Theobturator12 will typically have the configuration of anelongate rod30 extending between aproximal end32 and adistal end34. Aknob36 is disposed at theproximal end32 and atapered tip38 is formed at thedistal end34. Theobturator12 is adapted to be inserted into the workingchannel25 of thesheath10 with theknob36 extending proximally of thesheath10, and thedistal end34 extending distally of thesheath10. This operative position of theobturator12 within thesheath10 is illustrated in the assembled view ofFIG. 2. An axial cross-section view of the assembled combination is illustrated inFIG. 3 where therod30 of theobturator12 is more clearly shown within the workingchannel25 of thesheath10.
• If desired, the releasable lock (not shown) can be provided to removably attach theobturator12 to thesheath10. When locked in place, theobturator12 andsheath10 can then be passed as a single unit over the guidewire. This arrangement precludes inadvertent advancement of thesheath10 in front of theobturator12, which could greatly impede proper passage of the sheath and potentially the ureter.
• Thehandle23 associated with thesheath10 is of particular interest to the invention and is illustrated in the enlarged, axial cross-section view ofFIG. 4. From this view it can be seen that thehandle23 has the general configuration of the bell of a horn. Thehandle23 has a distally-facingsurface41 on the outside of thehandle23, and a proximally-facingsurface43 on the inside of thehandle23. Both of thesesurfaces41 and43 in the preferred embodiment are continuous and have a generally conical configuration. In the illustrated embodiment, the distally-facingsurface41 is generally concave, while the proximally-facingsurface43 is generally convex.
• Thehandle23 can be provided with twosmall holes45,46 for passage ofsutures47 and48, respectively. Once the sheath is in place, thesutures47,48 can be clamped with hemostats (not shown) to the surgical drapes, thereby preventing distal migration of the sheath and loss of ureteral access. Once the obturator/sheath combination has been advanced to the desired position in the ureter, theobturator12 can be unlocked from thesheath10 and removed. In the manner discussed in greater detail below, these features offer particular advantages to the present invention.
• One of the purposes of the proximally-facingsurface43 is to funnel theobturator12 and other surgical instrumentation into the workingchannel25 of thesheath10. With the generally conical configuration, this proximally-facing surface functions as a funnel with a radius which decreases with progressive distal positions along theaxis16. Thus, as the instrumentation is moved distally, the proximally-facingsurface43 guides the instrument along a decreasingly decreasing radius into the workingchannel25 of thesheath10. Providing thesurface43 with a generally convex configuration further facilitates this funneling feature of the invention. When thesurface43 is convex, its radius decreases at a decreasing rate with progressively equal distal positions along theaxis16.
• The distally-facingsurface41 is intended to facilitate engagement of thesheath10 by a user's hand held in its most natural state. InFIG. 5,adjacent fingers50 and52 of the user's hands are illustrated schematically by thecircles50 and52. In the natural state, the palm of the user's hands would be facing the user in the proximal direction, to the left inFIG. 5. Thesheath10 is adapted to be operatively positioned between thefingers50 and52 with thehandle23 positioned so that the distally-facingsurface41 is in juxtaposition to thefingers50 and52. This fit is facilitated by forming thesurface41 with a size and configuration generally similar to thefingers50 and52, as illustrated inFIG. 5. Thus, with the distally-facingsurface41 having a generally conical configuration, it has a radius which decreases with progressive distal positions along theaxis16. In an embodiment wherein thesurface41 is also concave, the radius of thesurface41 decreases at a decreasing rate with progressively equal distal positions along theaxis16.
• In operation, as the surgical instrument, such as theobturator12, is inserted into thehandle23, it produces a force F₁(illustrated by arrow54) in the distal direction. This force is opposed by thefingers50 and52, which engage the distally-facingsurface41 and apply opposing forces F₂and F₃(represented byarrows56 and58). In this manner, thefingers50 and52 can maintain thesheath10 generally stationary even when theobturator12 is being inserted. It will also be noted that with the user's hand in the natural position, it tends to form a barrier which prevents any instrumentation from extending exteriorly beyond thehandle23 into contact withureteral tissue60. As shown inFIG. 5, the urethra has a first diameter. Thetube14 has a second diameter that is less than the first diameter of the urethra while thehandle23 has a third diameter greater than the first diameter of the urethra.
• Although the embodiment ofFIG. 5 is particularly adapted to facilitate insertion of a surgical instrument, such as theobturator12, it will be appreciated that removal of the instrument also creates withdrawal forces on thesheath10. A further embodiment of the handle, which can easily accommodate not only insertion forces but also withdrawal forces, is illustrated inFIG. 6 In this embodiment, ahandle61 is similar to thehandle23, except that the outer, distally-facingsurface41 is curved distally outwardly to form a proximally-facingouter surface63. In this case, the twosurfaces41 and63 form a continuous surface which defines an annular recess sized and configured to receive thefingers50 and52.
• In this embodiment, insertion of the instrument, such as theobturator12, is resisted by the forces F₂and F₃applied by thefingers50 and52, respectively, to the distally-facingsurface43, as previously discussed with reference toFIG. 5. In a similar manner, when the instrument such as theobturator12 is withdrawn, it produces a force F₄(illustrated by arrow65) which must be resisted in order to maintain thesheath10 stationary. This resistance is provided in the embodiment ofFIG. 6 by the pressure of thefingers50,52 against the proximally-facingouter surface63. Thus,fingers50,52 provide opposing forces F₅and F₆designated byarrows67,70, respectively.
• FIGS. 7-9 illustrated a further embodiment involving a handle, such as thehandles23 or61, which is movable relative to thetube14 of thesheath10. This embodiment is particularly desirable as it permits thetube14 to be cut in situ, at the operative site, to a preferred length. With a sheath of this type, only a single access device need be present at the operative site. Multiple sheaths having different lengths are not required to be present in order to have a sheath of the desired length. As illustrated inFIG. 7, this embodiment of thesheath10 includes thetube14 which is slidingly engageable by ahandle assembly72 that includes asleeve74 and afunnel76. Thesleeve74 is formed as acylinder77 having aninterior bore78 andexternal threads81. Anelastomeric element83 is disposed within thebore78 and is provided with an axial lumen84 appropriately sized to receive thetube14.
• Thefunnel76 is formed similar to thehandle23, but includes twoconcentric cylinders85 and87 which extend distally. Theouter cylinder85 is provided withinterior threads90, which are sized to receive theexternal threads81 of thesleeve74. Theinner cylinder87 of thefunnel76 is provided with an outer diameter less than the inner diameter of thebore78. Thisinner cylinder87 extends to adistal surface92.
• In operation, thefunnel76 is moved axially over thesleeve74 and theinternal threads90 are screwed onto theexternal threads81. Further rotation of thefunnel76 relative to thesleeve74, causes thedistal surface92 of theinner cylinder87 to axially compress theelastomeric element83. This compression causes theelement83 to expand inwardly decreasing the diameter of its lumen84 and thereby increasing the frictional engagement of thehandle assembly72 relative to thetube14.
• In order to provide thesheath10 with a desired length, thetube14 can be cut to a predetermined length, either before or after mounting thehandle assembly72 on thetube14. Axial movement of thehandle assembly72 to a desired proximal location on thetube14 provides thesheath10 with the desired length. Operation of thehandle72 in the manner previously discussed will fix theassembly72 on thetube14 at this desired location.
• In another embodiment illustrated inFIG. 10, amovable handle assembly96 includes afunnel98 similar to thehandle23. It also includes acylinder99 which extends distally withinportions101 which have a reduced diameter. Aseparate finger clamp102 includes acylinder104 which has a diameter which is dependent upon operation offinger tabs103 and105. When thesetabs103 and105 are compressed, thecylinder104 has a relatively large diameter. When thetabs103 and105 are not compressed, thecylinder104 is biased toward a reduced diameter. Thisfinger clamp102 is intended to be operatively disposed over thethin portions101 of thecylinder99, as illustrated inFIG. 11. In this operative position, theentire handle assembly96 can be moved along thetube14 by compressing thefinger tabs103 and105 of theclamp102. Thetube14 can then be cut, for example, withscissors106, to any desired length. Compressing thefinger tabs103 and105 will permit thehandle assembly96 to be moved to a distal position, as illustrated inFIG. 11, where thetabs103 and105 can be released to compress thethin portions101 and maintain thehandle assembly96 in a fixed relationship with thetube14.
• A further embodiment of the invention is illustrated in the side-view ofFIG. 12. In this embodiment, thetube14 is formed with an innerplastic body110, surrounded by ametal spring coil112, which is further covered by anouter body114. This particular embodiment of thetube14 provides a high degree of kink resistance and can be used with any of the handle assemblies previously discussed. With this embodiment of thetube14, theinner body110 provides a smooth surface within thesheath10, which facilitates passage of instrumentation. Thespring coil112 adds kink resistance to thetube14, while theouter body114 provides a suitable covering for the coils of thespring112.
• From the foregoing description of preferred embodiments, it will be apparent that many variations on the concept of this invention will be contemplated by those skilled in the art. For example, many different configurations of thetube14 can be used with the various handle assemblies disclosed. Furthermore, the handle assemblies can be embodied in many different forms to provide at least one curved outer surface which is sized and configured to receive the fingers of a user's hand in a normal position. The fact that this desired outer shape can be combined with a funnel configuration at the20 proximal end of the sheath will add further advantages to these various embodiments.
• Although exemplary embodiments of the invention have been shown and described, many other changes, modifications, and substitutions will now be apparent to those of ordinary skill in the art, without necessarily departing from the spirit and scope of this invention as set forth in the following claims.

Claims (28)

1. A ureteral access sheath adapted for insertion into a urethra having a diameter D₁, the access sheath being adapted for use by a person having a pair of adjacent fingers, the access sheath comprising:

an elongate tube having a diameter D₂and a lumen extending between a proximal end and distal end, the diameter D₂being smaller than the diameter D₁of the urethra, wherein the elongate tube includes a helical spring;

a first handle disposed at the proximal end of the tube;

portions of the first handle extending radially outwardly of the tube to provide the first handle with a diameter D₃that is greater than the diameter D₁of the urethra, the handle portions being defined by a first surface facing generally distally and a second surface facing generally proximally; and

a second handle disposed distally of the first handle, the second handle including a third surface facing generally proximally

wherein the first surface and the third surface are concave, continuous and both sized and configured to receive the adjacent fingers of the user,

wherein the first surface is continuous with the third surface so as to define an annular recess,

wherein the second surface is convex so as to form a funnel leading into the lumen of the tube,

whereby the handle portions inhibit distal migration of the proximal end of the tube into the urethra.

2. The access sheath recited inclaim 1 wherein the second surface extends decreasingly radially inwardly with progressive equal distal positions along the tube.

3. The access sheath recited inclaim 2 wherein the first surface extends decreasingly radially inwardly with progressive equal distal positions along the tube.

4. A ureteral access sheath, comprising:

an elongate tube having a lumen extending between a proximal end and a distal end;

a handle disposed at the proximal end of the tube having a flared configuration, a first surface facing generally distally, and a second surface facing generally proximally and configured to funnel instrumentation into the lumen; and

a coiled spring formed around the elongate tube and having an outer body covering the coiled spring.

5. The ureteral access sheath ofclaim 4, wherein the first surface is concave.

6. The ureteral access sheath ofclaim 5, wherein the second surface is convex.

7. The ureteral access sheath ofclaim 4, wherein the first surface is convex.

8. The ureteral access sheath ofclaim 7, wherein the second surface is concave.

9. The ureteral access sheath ofclaim 4, wherein the coiled spring provides kink resistance to the tube.

10. The ureteral access sheath ofclaim 4, wherein the tube provides a smooth surface to facilitate passage of the instrument.

11. The ureteral access sheath ofclaim 4, wherein the outer body provides covering for the coils of the spring.

12. The ureteral access sheath ofclaim 4, wherein the instrumentation includes an obturator comprising an elongate rod extending between a proximal end and a distal end.

13. The ureteral access sheath ofclaim 12, wherein the obturator further includes a releasable mechanism disposed at the proximal end of the elongate rod that is removably attachable to the handle.

14. The ureteral access sheath ofclaim 13, wherein the attachment of the obturator to the sheath precludes inadvertent advancement of the sheath in front of the obturator.

15. A ureteral access sheath, comprising:

an elongate tube having a lumen extending between a proximal end and a distal end;

a handle disposed at the proximal end of the tube, the handle extending radially outwardly of the tube forming a funnel with an opening leading into the lumen of the tube;

a coiled spring formed around the elongate tube and having an outer body covering the coiled spring.

16. The ureteral access sheath ofclaim 15, wherein the coiled spring provides kink resistance to the tube.

17. The ureteral access sheath ofclaim 15, wherein the tube provides a smooth surface to facilitate passage of an instrument.

18. The ureteral access sheath ofclaim 15, wherein the outer body provides covering for the coils of the spring.

19. The ureteral access sheath ofclaim 17, wherein the instrumentation includes an obturator comprising an elongate rod extending between a proximal end and a distal end.

20. The ureteral access sheath ofclaim 19, wherein the obturator further includes a releasable mechanism disposed at the proximal end of the elongate rod that is removably attachable to the handle.

21. The ureteral access sheath ofclaim 20, wherein the attachment of the obturator to the sheath precludes inadvertent advancement of the sheath in front of the obturator.

22. A ureteral access sheath, comprising:

an elongate tube having a lumen extending between a proximal end and a distal end;

a handle disposed at the proximal end of the tube, the handle extending radially outwardly of the tube forming a funnel with an opening leading into the lumen of the tube;

a coiled spring incorporated into the elongate tube.

23. The ureteral access sheath ofclaim 22, wherein the coiled spring provides kink resistance to the tube.

24. The ureteral access sheath ofclaim 22, wherein the tube provides a smooth surface to facilitate passage of an instrument.

25. The ureteral access sheath ofclaim 22, wherein the outer body provides covering for the coils of the spring.

26. The ureteral access sheath ofclaim 24, wherein the instrumentation includes an obturator comprising an elongate rod extending between a proximal end and a distal end.

27. The ureteral access sheath ofclaim 26, wherein the obturator further includes a releasable mechanism disposed at the proximal end of the elongate rod that is removably attachable to the handle.

28. The ureteral access sheath ofclaim 27, wherein the attachment of the obturator to the sheath precludes inadvertent advancement of the sheath in front of the obturator.

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