Balloon trocar

• US 20070239108A1
• Filed: 03/13/2006
• Published: 10/11/2007
• Est. Priority Date: 03/13/2006
• Status: Active Grant

• Current Assignee: Applied Medical Resources Corporation (Applied Medical Corporation)
• Original Assignee: Applied Medical Resources Corporation (Applied Medical Corporation)
• Inventors: Nguyen, Eric, Johnson, Gary, Au, Gigi, Hart, Charles, Brustad, John, Gadberry, Donald, Albrecht, Jeremy
• Granted Patent: US 8,147,453 B2
• Time in Patent Office: Days
• US Class Current: 604/96.10
• CPC Class Codes: A61B 17/0218 for minimally invasive surgery A61B17/0281, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence
• CPC Class Codes: A61B 17/3415 for introducing tubes or catheters, e.g. gastrostomy tubes, drain catheters A61B17/3417 takes precedence; body piercing catheter guide needles A61M25/06
• CPC Class Codes: A61B 17/3417 Details of tips or shafts, e.g. grooves, expandable, bendable; Multiple coaxial sliding cannulas, e.g. for dilating syringe needles A61M5/32; dilators A61M29/00
• CPC Class Codes: A61B 17/3421 Cannulas
• CPC Class Codes: A61B 17/3423 Access ports, e.g. toroid shape introducers for instruments or hands access sites for liquids A61M39/0247
• CPC Class Codes: A61B 17/3498 Valves therefor, e.g. flapper valves, slide valves haemostasis valves A61M39/06; check valves A61M39/24
• CPC Class Codes: A61B 2017/00477 Coupling A61B2017/0046 takes precedence
• CPC Class Codes: A61B 2017/00557 inflatable A61B2017/22051 takes precedence
• CPC Class Codes: A61B 2017/22051 with an inflatable part, e.g. balloon, for positioning, blocking, or immobilisation A61B2017/22048, A61B2017/3486 take precedence
• CPC Class Codes: A61B 2017/3419 Sealing means between cannula and body
• CPC Class Codes: A61B 2017/3433 with different outer diameters of the cannula
• CPC Class Codes: A61B 2017/3445 used as instrument channel for multiple instruments catheters A61B2017/22072
• CPC Class Codes: A61B 2017/347 Locking means, e.g. for locking instrument in cannula
• CPC Class Codes: A61B 2017/3486 Balloon
• CPC Class Codes: A61B 2017/3488 Fixation to inner organ or inner body tissue
• CPC Class Codes: A61B 2017/349 Trocar with thread on outside
• CPC Class Codes: A61J 15/0053 Means for fixing the tube outside of the body, e.g. by a special shape, by fixing it to the skin holding devices, e.g. on the body A61M25/02, mouthpieces for tracheal tubes A61M16/0488; transcutaneous access sites A61M39/0247
• CPC Class Codes: A61M 2039/0261 Means for anchoring port to the body, or ports having a special shape or being made of a specific material to allow easy implantation/integration in the body
• CPC Class Codes: A61M 2039/0273 for introducing catheters into the body
• CPC Class Codes: A61M 2039/0279 for introducing medical instruments into the body, e.g. endoscope, surgical tools
• CPC Class Codes: A61M 2039/0294 : having a specific shape matching the shape of a tool to be inserted therein, e.g. for easy introduction, for sealing purposes, guide
• CPC Class Codes: A61M 2039/062 : used with a catheter
• CPC Class Codes: A61M 2039/0626 : used with other surgical instruments, e.g. endoscope, trocar
• CPC Class Codes: A61M 2039/0686 : comprising more than one seal
• CPC Class Codes: A61M 25/04 : in the body, e.g. expansible A61M25/10, A61M16/0488 take precedence
• CPC Class Codes: A61M 39/0247 : Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body peritoneal dialysis catheters A61M1/285; tracheostomy devices A61M16/0465; measuring pressure within the body A61B5/03; colostomy devices A61F5/445; gastrotomy feeding tubes A61J15/0015; means for fixing a feeding tube outside of the body A61J15/0053
• CPC Class Codes: A61M 39/06 : Haemostasis valves, i.e. gaskets sealing around a needle, catheter or the like, closing on removal thereof

Abstract

A balloon trocar includes a cannula assembly including a cannula and an outer sleeve fitting over the cannula. The distal end of the outer sleeve is proximal to the distal end of the cannula. A balloon is coupled to a distal portion of the sleeve and a distal portion of the cannula. The outer surface of the cannula includes a plurality of longitudinal channels for transmitting gas or fluid to the balloon. A bolster having a gel pad at its distal portion is slidably mounted to the cannula assembly and may be locked in a desired position. In use, the trocar is inserted into an incision through a body wall and into a body cavity. The balloon is inflated and the cannula assembly pulled proximally against the incision while the bolster is slid distally to the body wall and locked in place to seal the incision with the compressed balloon.

Claims

1. A cannula assembly, comprising:

a cannula including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a proximal portion having a first, larger periphery, a distal portion having a second, smaller periphery, an annular groove on the outer surface of the distal portion of the cannula toward the distal end of the cannula, and a plurality of channels on the outer surface of the distal portion of the cannula, the channels extending along the length of the cannula from substantially a proximal end of the distal portion of the cannula distally to a point proximal to the annular groove near the distal end of the cannula;

a sleeve including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a proximal portion having a first, larger periphery, a distal portion having a second, smaller periphery, and an annular groove on the outer surface of the distal portion of the sleeve toward the distal end of the sleeve, the lumen of the sleeve being configured to accept the cannula;

a balloon including a tubular sleeve; and

a seal,

wherein the sleeve is positioned over the cannula with the proximal portion of the sleeve fitting over at least a distal region of the proximal portion of the cannula and the distal portion of the sleeve fitting over at least a portion of the distal portion of the cannula,

the distal end of the sleeve being positioned proximal to a distal end of the plurality of channels on the outer surface of the cannula,

the cannula and the sleeve being coupled together at the proximal portion of the cannula and the proximal portion of the sleeve,

the seal being positioned between the cannula and the sleeve and compressed sufficiently to form a seal between the cannula and the sleeve,

the balloon being sufficiently long to extend between and cover the annular groove on the outer surface of the distal portion of the cannula and the annular groove on the outer surface of the distal portion of the sleeve, and

the space between the outer surface of the cannula with the channels, the inner surface of the sleeve, the seal and the balloon form a substantially closed chamber.

2. The cannula assembly of claim 1, wherein:

the proximal portion of the cannula includes a substantially cylindrical portion having a first, larger circumference and the distal portion of the cannula includes a substantially cylindrical portion having a second, smaller circumference; and

the proximal portion of the sleeve includes a substantially cylindrical portion having a first, larger circumference and the distal portion of the sleeve includes a substantially cylindrical portion having a second, smaller circumference.

3. The cannula assembly of claim 1, wherein the plurality of channels on the outer surface of the cannula includes a plurality of substantially longitudinal grooves that are substantially parallel to a longitudinal axis of the cannula.

4. The cannula assembly of claim 1, wherein the seal is an o-ring.

5. The cannula assembly of claim 4, wherein the o-ring is made of a material having a hardness of about 40 Shore A.

6. The cannula assembly of claim 4, wherein the seal is positioned between the proximal portion of the cannula and the proximal portion of the sleeve.

7. The cannula assembly of claim 4, wherein:

the cannula includes a transition region between the proximal portion of the cannula and the distal portion of the cannula; and

the sleeve includes a transition region between the proximal portion of the sleeve and the distal portion of the sleeve.

8. The cannula assembly of claim 7, wherein the seal is positioned between the transition region of the cannula and the transition region of the sleeve.

9. The cannula assembly of claim 1, wherein the cannula and the sleeve are coupled together at a position proximal to the seal.

10. The cannula assembly of claim 9, wherein the means for coupling the cannula to the sleeve includes a snap fitting comprising at least one projection on the outer surface of the cannula and at least one notch on the inner surface of the sleeve.

11. The cannula assembly of claim 10, wherein the snap fitting comprises:

two projections positioned substantially circumferentially opposite each other on the outer surface of the cannula; and

two notches positioned substantially circumferentially opposite each other on the inner surface of the sleeve.

12. The cannula assembly of claim 1, further comprising a locking means to substantially prevent the cannula and the sleeve from rotating relative each other about a longitudinal axis of the cannula and a longitudinal axis of the sleeve.

13. The cannula assembly of claim 12, the locking means comprising:

a projection on the outer surface of the proximal portion of the cannula; and

a channel on the inner surface of the proximal portion of the sleeve.

14. The cannula assembly of claim 13, wherein the channel is substantially longitudinal and substantially parallel to the axis of the sleeve.

15. The cannula assembly of claim 1, further comprising:

a first winding of thread around the balloon in the area that overlaps the annular groove at the distal portion of the cannula and forces the portion of the balloon that overlaps the annular groove at the distal portion of the cannula into the annular groove at the distal portion of the cannula; and

a second winding of thread around the balloon in the area that overlaps the annular groove at the distal portion of the sleeve and forces the portion of the balloon that overlaps the annular groove at the distal portion of the sleeve into the annular groove at the distal portion of the sleeve.

16. The cannula assembly of claim 1, wherein the balloon includes a substantially toroid shape upon inflation of the balloon.

17. The cannula assembly of claim 1, the tubular sleeve of the balloon including an elastomeric tubular sleeve.

18. The cannula assembly of claim 1, further comprising a second tubular sleeve positioned over the tubular sleeve of the balloon, the second tubular sleeve being formed of an elastomeric material.

19. The cannula assembly of claim 18, further comprising:

a first winding of thread around the balloon and second tubular sleeve in the area that overlaps the annular groove at the distal portion of the cannula and forces the portion of the balloon and second tubular sleeve that overlaps the annular groove at the distal portion of the cannula into the annular groove at the distal portion of the cannula; and

a second winding of thread around the balloon and second tubular sleeve in the area that overlaps the annular groove at the distal portion of the sleeve and forces the portion of the balloon and second tubular sleeve that overlaps the annular groove at the distal portion of the sleeve into the annular groove at the distal portion of the sleeve.

20. The cannula assembly of claim 1, wherein the sleeve includes an inflation port positioned distal to the seal.

21. The cannula assembly of claim 1, further comprising a bolster slidably adjustable along the length of the sleeve proximal to the balloon.

22. The cannula assembly of claim 21, the bolster comprising:

a base;

a clamping mechanism at a proximal portion of the base, the clamping mechanism including an over-center lock design; and

a pad at a distal portion of the base, the pad including a substantially incompressible gel material.

23. The cannula assembly of claim 1, further comprising:

an obturator positioned within the lumen of the cannula, the obturator comprising,

an elongate shaft extending along a substantially longitudinal axis between a proximal end and a distal end,

a distal tip having a prolate spheroid shape, and

a handle portion having a larger periphery than the elongate shaft, the handle being positioned at a proximal portion of the obturator,

wherein the shaft and distal tip are sized and configured to slide within the lumen of the cannula, and

in an operative position, the distal tip of the obturator is positioned distal to the distal end of the cannula and the handle portion of the obturator is positioned proximal to the proximal end of the cannula.

24. The cannula assembly of claim 1, further comprising:

a trocar seal positioned at the proximal portion of the cannula, the trocar seal including a valve that provides an instrument seal in the presence of an instrument and provides a zero-seal in the absence of an instrument.

25. The cannula assembly of claim 24, the trocar seal being removable from the cannula assembly.

26. The cannula assembly of claim 1, the inner surface of the distal portion of the sleeve including a plurality of channels extending along the length of the sleeve from substantially a proximal end of the distal portion of the sleeve distally to the distal end of the sleeve.

27. The cannula assembly of claim 26, wherein the plurality of channels on the inner surface of the sleeve includes a plurality of substantially longitudinal grooves that are substantially parallel to a longitudinal axis of the sleeve.

28. A cannula assembly, comprising:

a cannula including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a proximal portion having a first, larger periphery, a distal portion having a second, smaller periphery, an annular groove on the outer surface of the distal portion of the cannula toward the distal end of the cannula, and a plurality of channels on the outer surface of the distal portion of the cannula, the channels extending along the length of the cannula from substantially a proximal end of the distal portion of the cannula distally to a point proximal to the annular groove near the distal end of the cannula;

a sleeve including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a proximal portion having a first, larger periphery, a distal portion having a second, smaller periphery, and an annular groove on the outer surface of the distal portion of the sleeve toward the distal end of the sleeve, the lumen of the sleeve being configured to accept the cannula;

a balloon including a tubular sleeve, the balloon being sufficiently long to extend between and cover the annular groove on the outer surface of the distal portion of the cannula and the annular groove on the outer surface of the distal portion of the sleeve;

a seal;

a first winding of thread around the balloon in the area that overlaps the annular groove at the distal portion of the cannula and forces the portion of the balloon that overlaps the annular groove at the distal portion of the cannula into the annular groove at the distal portion of the cannula; and

a second winding of thread around the balloon in the area that overlaps the annular groove at the distal portion of the sleeve and forces the portion of the balloon that overlaps the annular groove at the distal portion of the sleeve into the annular groove at the distal portion of the sleeve,

wherein the sleeve is positioned over the cannula with the proximal portion of the sleeve fitting over at least a distal region of the proximal portion of the cannula and the distal portion of the sleeve fitting over at least a portion of the distal portion of the cannula,

the distal end of the sleeve being positioned proximal to a distal end of the plurality of channels on the outer surface of the cannula,

the cannula and the sleeve being coupled together at the proximal portion of the cannula and the proximal portion of the sleeve at a position proximal to the seal by a snap fitting, the snap fitting including at least one projection on the outer surface of the cannula and at least one notch on the inner surface of the sleeve,

the seal being positioned between the cannula and the sleeve and compressed sufficiently to form a seal between the cannula and the sleeve,

the sleeve including an inflation port positioned distal to the seal, and

the space between the outer surface of the cannula with the channels, the inner surface of the sleeve, the seal and the balloon forming a substantially closed chamber.

29. The cannula assembly of claim 28, wherein the plurality of channels on the outer surface of the cannula includes a plurality of substantially longitudinal grooves that are substantially parallel to a longitudinal axis of the cannula.

30. The cannula assembly of claim 28, wherein the seal is an o-ring.

31. The cannula assembly of claim 30, wherein the seal is positioned between the proximal portion of the cannula and the proximal portion of the sleeve.

32. The cannula assembly of claim 30, wherein:

the cannula includes a transition region between the proximal portion of the cannula and the distal portion of the cannula;

the sleeve includes a transition region between the proximal portion of the sleeve and the distal portion of the sleeve; and

the seal is positioned between the transition region of the cannula and the transition region of the sleeve.

33. The cannula assembly of claim 28, wherein the balloon includes a substantially toroid shape upon inflation of the balloon.

34. The cannula assembly of claim 28, the tubular sleeve of the balloon including an elastomeric tubular sleeve.

35. The cannula assembly of claim 28, further comprising:

a second tubular sleeve positioned over the tubular sleeve of the balloon, the second tubular sleeve being formed of an elastomeric material,

wherein the first winding of thread winds around the balloon and second tubular sleeve in the area that overlaps the annular groove at the distal portion of the cannula and forces the portion of the balloon and second tubular sleeve that overlaps the annular groove at the distal portion of the cannula into the annular groove at the distal portion of the cannula; and

the second winding of thread winds around the balloon and second tubular sleeve in the area that overlaps the annular groove at the distal portion of the sleeve and forces the portion of the balloon and second tubular sleeve that overlaps the annular groove at the distal portion of the sleeve into the annular groove at the distal portion of the sleeve.

36. The cannula assembly of claim 28, further comprising a bolster slidably adjustable along the length of the sleeve proximal to the balloon.

37. The cannula assembly of claim 36, the bolster comprising:

a base;

a clamping mechanism at a proximal portion of the base, the clamping mechanism including an over-center lock design; and

a pad at a distal portion of the base, the pad including a substantially incompressible gel material.

38. The cannula assembly of claim 28, further comprising:

an obturator positioned within the lumen of the cannula, the obturator comprising,

an elongate shaft extending along a substantially longitudinal axis between a proximal end and a distal end,

a distal tip having a prolate spheroid shape, and

a handle portion having a larger periphery than the elongate shaft, the handle being positioned at a proximal portion of the obturator,

wherein the shaft and distal tip are sized and configured to slide within the lumen of the cannula, and

in an operative position, the distal tip of the obturator is positioned distal to the distal end of the cannula and the handle portion of the obturator is positioned proximal to the proximal end of the cannula.

39. The cannula assembly of claim 28, further comprising:

a trocar seal positioned at the proximal portion of the cannula, the trocar seal including a valve that provides an instrument seal in the presence of an instrument and provides a zero-seal in the absence of an instrument.

40. The cannula assembly of claim 39, the trocar seal being removable from the cannula assembly.

41. The cannula assembly of claim 28, the inner surface of the distal portion of the sleeve including a plurality of channels extending along the length of the sleeve from substantially a proximal end of the distal portion of the sleeve distally to the distal end of the sleeve.

42. The cannula assembly of claim 41, wherein the plurality of channels on the inner surface of the sleeve includes a plurality of substantially longitudinal grooves that are substantially parallel to a longitudinal axis of the sleeve.

43. A cannula assembly, comprising:

a cannula including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a substantially cylindrical proximal portion having a first, larger circumference, a substantially cylindrical distal portion having a second, smaller circumference, a transition region between the proximal portion of the cannula and the distal portion of the cannula, an annular groove on the outer surface of the distal portion of the cannula toward the distal end of the cannula, and a plurality of substantially longitudinal grooves on the outer surface of the distal portion of the cannula, the longitudinal grooves being substantially parallel to a longitudinal axis of the cannula, the longitudinal grooves extending along the length of the cannula from substantially a proximal end of the distal portion of the cannula distally to a point proximal to the annular groove near the distal end of the cannula;

a sleeve including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a substantially cylindrical proximal portion having a first, larger circumference, a substantially cylindrical distal portion having a second, smaller circumference, a transition region between the proximal portion of the sleeve and the distal portion of the sleeve, and an annular groove on the outer surface of the distal portion of the sleeve toward the distal end of the sleeve, the lumen of the sleeve being configured to accept the cannula, the sleeve being positioned over the cannula with the proximal portion of the sleeve fitting over at least a distal region of the proximal portion of the cannula and the distal portion of the sleeve fitting over at least a portion of the distal portion of the cannula, the distal end of the sleeve being positioned proximal to a distal end of the plurality of longitudinal grooves on the outer surface of the cannula, the cannula and the sleeve being coupled together at the proximal portion of the cannula and the proximal portion of the sleeve;

a seal positioned between the transition region of the cannula and the transition region of the sleeve and compressed sufficiently to form a seal between the cannula and the sleeve;

a balloon including a tubular sleeve, the balloon being sufficiently long to extend between and cover the annular groove on the outer surface of the distal portion of the cannula and the annular groove on the outer surface of the distal portion of the sleeve;

a first winding of thread around the balloon in the area that overlaps the annular groove at the distal portion of the cannula and forces the portion of the balloon that overlaps the annular groove at the distal portion of the cannula into the annular groove at the distal portion of the cannula;

a second winding of thread around the balloon in the area that overlaps the annular groove at the distal portion of the sleeve and forces the portion of the balloon that overlaps the annular groove at the distal portion of the sleeve into the annular groove at the distal portion of the sleeve; and

a bolster slidably adjustable along the length of the sleeve proximal to the balloon, the bolster comprising,

a base,

a clamping mechanism at a proximal portion of the base, the clamping mechanism including an over-center lock design, and

a substantially incompressible gel pad at a distal portion of the base,

wherein, the space between the outer surface of the cannula with the longitudinal grooves, the inner surface of the sleeve, the seal and the balloon form a substantially closed chamber, and

the sleeve includes an inflation port positioned distal to the seal.

44. The cannula assembly of claim 43, wherein the seal is an o-ring.

45. The cannula assembly of claim 43, wherein the means for coupling the cannula to the sleeve includes a snap fitting comprising at least one projection on the outer surface of the cannula and at least one notch on the inner surface of the sleeve.

46. The cannula assembly of claim 45, wherein the snap fitting comprises:

two projections positioned substantially circumferentially opposite each other on the outer surface of the cannula; and

two notches positioned substantially circumferentially opposite each other on the inner surface of the sleeve.

47. The cannula assembly of claim 43, further comprising a locking means to substantially prevent the cannula and the sleeve from rotating relative each other about a longitudinal axis of the cannula and a longitudinal axis of the sleeve.

48. The cannula assembly of claim 47, the locking means comprising:

a projection on the outer surface of the proximal portion of the cannula; and

a channel on the inner surface of the proximal portion of the sleeve.

49. The cannula assembly of claim 48, wherein the channel is substantially longitudinal and substantially parallel to the axis of the sleeve.

50. The cannula assembly of claim 43, wherein the balloon includes a substantially toroid shape upon inflation of the balloon.

51. The cannula assembly of claim 43, the tubular sleeve of the balloon including an elastomeric tubular sleeve.

52. The cannula assembly of claim 43, further comprising:

a second tubular sleeve positioned over the tubular sleeve of the balloon, the second tubular sleeve being formed of an elastomeric material,

wherein the first winding of thread winds around the balloon and second tubular sleeve in the area that overlaps the annular groove at the distal portion of the cannula and forces the portion of the balloon and second tubular sleeve that overlaps the annular groove at the distal portion of the cannula into the annular groove at the distal portion of the cannula; and

the second winding of thread winds around the balloon and second tubular sleeve in the area that overlaps the annular groove at the distal portion of the sleeve and forces the portion of the balloon and second tubular sleeve that overlaps the annular groove at the distal portion of the sleeve into the annular groove at the distal portion of the sleeve.

53. The cannula assembly of claim 43, further comprising:

an obturator positioned within the lumen of the cannula, the obturator comprising,

an elongate shaft extending along a substantially longitudinal axis between a proximal end and a distal end,

a distal tip having a prolate spheroid shape, and

a handle portion having a larger periphery than the elongate shaft, the handle being positioned at a proximal portion of the obturator,

wherein the shaft and distal tip are sized and configured to slide within the lumen of the cannula, and

in an operative position, the distal tip of the obturator is positioned distal to the distal end of the cannula and the handle portion of the obturator is positioned proximal to the proximal end of the cannula.

54. The cannula assembly of claim 43, further comprising:

a trocar seal positioned at the proximal portion of the cannula, the trocar seal including a valve that provides an instrument seal in the presence of an instrument and provides a zero-seal in the absence of an instrument.

55. The cannula assembly of claim 54, the trocar seal being removable from the cannula assembly.

56. The cannula assembly of claim 43, the inner surface of the distal portion of the sleeve including a plurality of channels extending along the length of the sleeve from substantially a proximal end of the distal portion of the sleeve distally to the distal end of the sleeve.

57. The cannula assembly of claim 56, wherein the plurality of channels on the inner surface of the sleeve includes a plurality of substantially longitudinal grooves that are substantially parallel to a longitudinal axis of the sleeve.

58. A cannula assembly, comprising:

a cannula including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a proximal portion having a first, larger periphery, a distal portion having a second, smaller periphery, and an annular groove on the outer surface of the distal portion of the cannula toward the distal end of the cannula;

a sleeve including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a proximal portion having a first, larger periphery, a distal portion having a second, smaller periphery, an annular groove on the outer surface of the distal portion of the sleeve toward the distal end of the sleeve, a plurality of channels on the inner surface of the distal portion of the sleeve, the channels extending along the length of the sleeve from substantially a proximal end of the distal portion of the sleeve distally to the distal end of the sleeve, the lumen of the sleeve being configured to accept the cannula;

a balloon including a tubular sleeve; and

a seal,

wherein the sleeve is positioned over the cannula with the proximal portion of the sleeve fitting over at least a distal region of the proximal portion of the cannula and the distal portion of the sleeve fitting over at least a portion of the distal portion of the cannula,

the distal end of the sleeve being positioned proximal to a distal end of the plurality of channels on the outer surface of the cannula,

the cannula and the sleeve being coupled together at the proximal portion of the cannula and the proximal portion of the sleeve,

the seal being positioned between the cannula and the sleeve and compressed sufficiently to form a seal between the cannula and the sleeve,

the balloon being sufficiently long to extend between and cover the annular groove on the outer surface of the distal portion of the cannula and the annular groove on the outer surface of the distal portion of the sleeve, and

the space between the outer surface of the cannula with the channels, the inner surface of the sleeve, the seal and the balloon form a substantially closed chamber.

59. The cannula assembly of claim 58, wherein the plurality of channels on the inner surface of the sleeve includes a plurality of substantially longitudinal grooves that are substantially parallel to a longitudinal axis of the sleeve.

60. The cannula assembly of claim 58, wherein the cannula and the sleeve are coupled together at a position proximal to the seal.

61. The cannula assembly of claim 60, wherein the means for coupling the cannula to the sleeve includes a snap fifting comprising at least one projection on the outer surface of the cannula and at least one notch on the inner surface of the sleeve.

62. The cannula assembly of claim 58, further comprising a locking means to substantially prevent the cannula and the sleeve from rotating relative each other about a longitudinal axis of the cannula and a longitudinal axis of the sleeve.

63. The cannula assembly of claim 58, further comprising:

a first winding of thread around the balloon in the area that overlaps the annular groove at the distal portion of the cannula and forces the portion of the balloon that overlaps the annular groove at the distal portion of the cannula into the annular groove at the distal portion of the cannula; and

a second winding of thread around the balloon in the area that overlaps the annular groove at the distal portion of the sleeve and forces the portion of the balloon that overlaps the annular groove at the distal portion of the sleeve into the annular groove at the distal portion of the sleeve.

64. The cannula assembly of claim 58, wherein the balloon includes a substantially toroid shape upon inflation of the balloon.

65. The cannula assembly of claim 58, the tubular sleeve of the balloon including an elastomeric tubular sleeve.

66. The cannula assembly of claim 58, further comprising a second tubular sleeve positioned over the tubular sleeve of the balloon, the second tubular sleeve being formed of an elastomeric material.

67. The cannula assembly of claim 66, further comprising:

a first winding of thread around the balloon and second tubular sleeve in the area that overlaps the annular groove at the distal portion of the cannula and forces the portion of the balloon and second tubular sleeve that overlaps the annular groove at the distal portion of the cannula into the annular groove at the distal portion of the cannula; and

a second winding of thread around the balloon and second tubular sleeve in the area that overlaps the annular groove at the distal portion of the sleeve and forces the portion of the balloon and second tubular sleeve that overlaps the annular groove at the distal portion of the sleeve into the annular groove at the distal portion of the sleeve.

68. The cannula assembly of claim 58, further comprising a bolster slidably adjustable along the length of the sleeve proximal to the balloon.

69. The cannula assembly of claim 68, the bolster comprising:

a base;

a clamping mechanism at a proximal portion of the base, the clamping mechanism including an over-center lock design; and

a pad at a distal portion of the base, the pad including a substantially incompressible gel material.

70. The cannula assembly of claim 58, further comprising:

an obturator positioned within the lumen of the cannula, the obturator comprising,

an elongate shaft extending along a substantially longitudinal axis between a proximal end and a distal end,

a distal tip having a prolate spheroid shape, and

a handle portion having a larger periphery than the elongate shaft, the handle being positioned at a proximal portion of the obturator,

wherein the shaft and distal tip are sized and configured to slide within the lumen of the cannula, and

in an operative position, the distal tip of the obturator is positioned distal to the distal end of the cannula and the handle portion of the obturator is positioned proximal to the proximal end of the cannula.

71. The cannula assembly of claim 58, further comprising:

a trocar seal positioned at the proximal portion of the cannula, the trocar seal including a valve that provides an instrument seal in the presence of an instrument and provides a zero-seal in the absence of an instrument.

72. The cannula assembly of claim 71, the trocar seal being removable from the cannula assembly.