Apparatus and a method for automatically introducing implants into soft tissue with adjustable spacing

• US 6,270,472 B1
• Filed: 12/29/1998
• Issued: 08/07/2001
• Est. Priority Date: 12/29/1998
• Status: Expired due to Fees

• Current Assignee: University of Pittsburgh of The Commonwealth System of Higher Education
• Original Assignee: University of Pittsburgh of The Commonwealth System of Higher Education
• Inventors: Schauer, Philip, Holmes, John A., Greenberger, Joel S., Antaki, James F.
• Primary Examiner(s): KENNEDY, SHARON E
• Application Number:
  US09/222,172
• Time in Patent Office: 952 Days
• Field of Search: 604/57, 604/59-64, 604/502, 604/506, 604/93.01, 604/224, 600/3, 600/7, 600/8
• US Class Current: 604/61
• CPC Class Codes: A61M 37/0069 Devices for implanting pellets, e.g. markers or solid medicaments for introducing of radioactive sources for interstitial radiation therapy, i.e. brachytherapy A61N5/1027
• CPC Class Codes: A61N 2005/1011 Apparatus for permanent insertion of sources
• CPC Class Codes: A61N 5/1027 Interstitial radiation therapy

Abstract

Apparatus and a method for depositing multiple implants carrying radioactive isotopes, pharmalogical agents or transgenes, in soft tissue including tumors and organs with precise, selectable spacing between implants includes an introducer in the form of a tube which is inserted into the soft tissue and an obturator for pushing implants out of the introducer one at a time. An operating mechanism incrementally withdraws the introducer while the obturator remains stationary thereby depositing a single implant. The obturator is then coupled to the introducer for the remainder of the stroke to provide the spacing. In a preferred embodiment, the introducer is resequenced to lay down parallel rows of implants. An indicator records the total number of implants deposited. The distal end of the introducer is configured to retain the implants and allow them to be discharged into the soft tissue singly. The invention is particularly suited, but not limited, to depositing the implants using laporascopic or thorascopic techniques.

Claims

1. An apparatus for depositing implants having an implant length L_s in soft tissue, said apparatus comprising:

an introducer comprising an elongated tube having a distal end insertable into the soft tissue and a passage extending from a proximal end to said distal end in which a plurality of implants are adapted to be retained;

an obturator slidable within said passage in said introducer from said proximal end and bearing against said implants;

a sleeve through which said introducer slidably extends; and

an operating mechanism comprising means repetitively, incrementally withdrawing said introducer reward relative to said sleeve a distance L and means automatically coupling said obturator to said introducer after said introducer has been withdrawn a distance L_s equal to the length of the implant to withdraw said obturator with said introducer for the remainder of said distance L equal to L_p, whereby implants are deposited in said soft tissue with a spacing equal to L_p.

2. The apparatus of claim 1 wherein said operating mechanism includes adjusting means for adjusting said distance L_p.

3. The apparatus of claim 1 adapted for depositing implants in soft tissue located in a cavity having an external wall, said sleeve having a tubular extension insertable through an incision in said external wall for aligning said introducer which extends through said tubular extension with said soft tissue.

4. The apparatus of claim 1 wherein said introducer has an enlarged proximal end forming a tubular member which is received in said sleeve, and wherein said means incrementally withdrawing said introducer rearward comprises an actuator including a trigger supported on said tubular member, a slide slidable forward relative to said tubular member upon actuation of said trigger, and a one-way clutch locking said slide to said sleeve as said trigger is actuated to incrementally withdraw said tubular member rearward said distance L with respect to said sleeve, and said means automatically coupling said obturator to said introducer comprises holding means engaged by said slide holding said obturator stationary relative to said sleeve until said introducer has been withdrawn said distance L_s and a slip clutch through which said obturator slips as said introducer moves said distance L_s and which couples said obturator to said introducer for movement with said introducer over said distance L_p.

5. The apparatus of claim 4 wherein said one-way clutch comprises a rack on one of said slide and said sleeve, and a pawl member on the other of said rack and said slide and said sleeve which engages said rack.

6. The apparatus of claim 5 wherein said means incrementally withdrawing said introducer further includes means biasing said slide rearward on release of said trigger, and means resisting rearward movement of said tubular member relative to said sleeve, said rack having teeth over which said pawl member slides as said slide moves rearward.

7. The apparatus of claim 6 wherein said one-way clutch further includes a pawl mount disengaging said pawl member from said rack for selectively repositioning said tubular member forward relative to said sleeve.

8. The apparatus of claim 7 wherein said rack is on said slide and said pawl mount mounts said pawl member on said sleeve.

9. The apparatus of claim 4 wherein said means holding said obturator stationary relative to said sleeve comprises a fore shuttle slidable in said tubular member, and a directional clutch blocking inward movement of said obturator relative to said fore shuttle.

10. The apparatus of claim 9 wherein said means holding said obturator further includes a decoupling spring between said slide and said fore shuttle holding said fore shuttle stationary relative to said sleeve while said introducer moves said distance L_s relative to said sleeve and until said fore shuttle seats relative to said tubular member and moves with said tubular member, and therefore said introducer, over said distance L_p against said decoupling spring.

11. The apparatus of claim 10 wherein said means holding said obturator further includes a return spring between said fore shuttle and said tubular member biasing said fore shuttle away from seating relative to said tubular member, said decoupling spring being stronger than said return spring.

12. The apparatus of claim 4 wherein said operating mechanism further includes adjusting means for adjusting said distance L_p.

13. The apparatus of claim 12 wherein said means for adjusting said distance L_p comprises means limiting movement of said slide.

14. The apparatus of claim 13 wherein said means for limiting movement of said slide comprises a tubular adjusting member threaded onto an inner end of said tubular member with an eccentric cam surface forming an adjustable stop limiting travel of said slide.

15. The apparatus of claim 14 including a housing for said obturator extending rearward from said tubular adjusting member and through which said obturator is visible, said housing having a graticule thereon providing a scale for indicating a count of implants deposited, and a helical scribe line on said obturator which registers with said graticule to indicate said count.

16. The apparatus of claim 4 wherein said one-way clutch comprises a rack on said slide and a pawl member mounted on said sleeve and engaging said rack to resist rearward movement of said slide, said holding means holding said obturator stationary relative to said sleeve comprises a fore shuttle slidable in said sleeve forward of said slide, and a directional clutch blocking rearward movement of said obturator relative to said fore shuttle, said holding means further including a decoupling spring between said slide and said fore shuttle holding said fore shuttle stationary relative to said slide while said introducer moves said distance L_s at which point said fore shuttle seats relative to said introducer and moves with said introducer, a slip clutch between said introducer and said obturator through which said obturator slides while being held stationary relative to said sleeve by said fore shuttle and which moves said obturator with said introducer with said fore shuttle moving with said introducer, and a return spring biasing said fore shuttle away from seating relative to said tubular member, said rack having teeth over which said pawl member slides as said slide is driven rearward by said decoupling spring and return spring upon release of said trigger.

17. The apparatus of claim 16 including means adjusting said distance L_p and comprising a tubular adjusting member threaded onto an inner end of said tubular member with an eccentric cam surface forming an adjustable stop engaging said trigger.

18. The apparatus of claim 1 wherein said means incrementally withdrawing said introducer comprises a carriage slidable within said sleeve, means reciprocating said carriage forward and rearward within said sleeve, and means coupling said introducer to said carriage only as said carriage moves rearward.

19. The apparatus of claim 18 wherein said means coupling said obturator to said introducer comprises a shuttle slidable in said housing rearward and forward, and means positioning said shuttle for engagement by and movement rearward with said carriage after said introducer has been moved rearward by said carriage said distance L_s.

20. The apparatus of claim 19 wherein said means positioning said shuttle for engagement by said carriage comprises first bias means biasing said shuttle toward the carriage, and a first stop against which said shuttle is biased by said first bias means setting said distance L_s at which said shuttle is engaged by said carriage.

21. The apparatus of claim 20 wherein said operating mechanism includes adjusting means for adjusting said distance L_p between said implants.

22. The apparatus of claim 21 wherein said adjusting means comprises means adjusting relative to said sleeve the position of a second stop against which said shuttle is seated by rearward movement of said shuttle.

23. The apparatus of claim 22 wherein said second stop is carried on a threaded member threaded onto said sleeve for movement rearward and forward relative to said sleeve.

24. The apparatus of claim 23 including indicator means associated with said threaded member providing an indication of said distance L_p.

25. The apparatus of claim 18 wherein said means reciprocating said carriage within said sleeve comprises a trigger assembly and a trigger coupling coupling said trigger assembly to said carriage.

26. The apparatus of claim 25 wherein said trigger assembly comprises a trigger member, means mounting said trigger member for rectilinear movement generally transverse to said introducer, and said trigger coupling means comprises a coupling pin on one of said trigger member and said carriage, and a coupling slot on the other of said trigger member and said carriage oriented at an angle to both said rectilinear movement of said trigger member and rearward and forward movement of said carriage and engaged by said coupling pin, and second bias means biasing said carriage forward.

27. The apparatus of claim 26 wherein said operating mechanism includes adjusting means for adjusting said distance L_p between said implants.

28. The apparatus of claim 27 wherein said adjusting means comprises means adjustably setting a length L_r of said rectilinear movement of said trigger member.

29. The apparatus of claim 27 wherein said means adjusting the length of L_r of rectilinear movement of said trigger member comprises an adjustment screw against which said trigger member seats in driving said carriage rearward.

30. The apparatus of claim 1 wherein said means repetitively, incrementally withdrawing said introducer rearward relative to said sleeve comprises a walking mechanism incrementally walking rearward in said sleeve said distance L.

31. The apparatus of claim 30 wherein said walling mechanism comprises a first actuating member secured to said introducer adjacent said proximal end, a glide slidable in said sleeve rearward of said introducer, a second actuating member secured to said glide, first clutch means restraining forward movement of said introducer, second clutch means restraining forward movement of said glide, a spring biasing said introducer and glide apart, said first and second actuator members being positioned for movement toward each other in response to an external actuating force to draw said introducer rearward said distance L with said second clutch means holding said glide against forward movement, and said actuating members being separated by said spring with release of said external force to push said glide rearward with said first clutch means holding said introducer against forward movement.

32. The apparatus of claim 31 wherein said means automatically coupling said obturator to said introducer comprises a shuttle slidable relative to said glide between said introducer and said glide and engaged by and moved rearward with said introducer after said introducer has moved rearward said distance L_s, and means on said shuttle gripping said obturator for rearward movement with said shuttle.

33. The apparatus of claim 32 wherein said glide has a shuttle stop limiting forward movement of said shuttle relative to said glide and a second spring biasing said shuttle against said shuttle stop.

34. The apparatus of claim 33 wherein said walfing mechanism further includes third clutch means restraining rearward movement of said obturator relative to said introducer.

35. The apparatus of claim 34 wherein said walking mechanism further includes fourth clutch means restraining rearward movement of said obturator with said introducer until said shuttle is engaged by said introducer.

36. The apparatus of claim 31 wherein said walking mechanism further comprises adjusting means limiting movement of said first actuating member and second actuating member toward each other to adjust the distance L_p between implants.

37. The apparatus of claim 1 wherein said operating mechanism further comprises implant indicator means indicating the number of implants implanted.

38. The apparatus of claim 37 wherein said operating mechanism includes a tubular adjusting member threaded onto a proximal end of said sleeve with threads of a selected pitch for adjusting said spacing L_p, and wherein said implant indicator means comprises a tubular obturator housing extending rearward from said tubular adjusting member into which said obturator extends and through which said obturator is visible, said obturator housing having a graticule thereon providing a scale for indicating a count of implants deposited, and a helical scribe line on said obturator having said selected pitch and which registers with said graticule to indicate said count.

39. The apparatus of claim 1 wherein said introducer has restraining means at said distal end for retaining said implants in said passage until pushed out of said distal end by inward movement of said introducer while said obturator remains stationary.

40. The apparatus of claim 39 wherein said restraining means comprises at least one radially inwardly directed deformation in said introducer, and at least one strain relief cut in said introducer adjacent said at least one radially inwardly directed deformation.

41. The apparatus of claim 3 wherein said tubular member has at least a section which is transparent and is provided with an introducer gauge, and said introducer has a depth indicator thereon which registers with said introducer gauge to provide an indication of the depth of penetration of said introducer into said soft tissue.

42. The apparatus of claim 1 wherein said introducer is sharpened at said distal end of said elongated tube, and has implant restraining means incorporated into said sharpened distal end for reducing said passage at said sharpened distal end to an inscribed opening smaller in lateral dimension than a lateral dimension of said at least one implant yet resiliently expanding said passage at said sharpened distal end for ejection of said at least one implant.

43. The apparatus of claim 42 wherein said implant restraining means comprises at least one radially inwardly directed deformation in said elongated tube, and at least one strain relief cut in said elongated tube adjacent said at least one radially inwardly directed deformation.

44. The apparatus of claim 43 wherein said at least one radially inwardly directed deformation in said elongated tube comprises a crimp.

45. The apparatus of claim 44 wherein said at least one radially inwardly directed deformation comprises a dimple.

46. The apparatus of claim 43 wherein said at least one strain relief cut comprises at least one longitudinal slit extending through said elongated tube.

47. The apparatus of claim 46 wherein said at least one elongated slit is open at said distal end of said introducer.

48. The apparatus of claim 46 wherein said at least one elongated slit is closed.

49. The apparatus of claim 43 wherein said at least one strain relief cut comprises a kerf partially extending through said elongated tube.

50. The apparatus of claim 42 wherein said sharpened distal end is formed by a single chamfer.

51. The apparatus of claim 42 wherein said sharpened distal end of said introducer is formed by a double chamfer.

52. The apparatus of claim 42 including a plurality of implants contained in said longitudinal passage.

53. Apparatus for depositing implants in soft tissue comprising:

a tubular member;

an introducer comprising an elongated tube adapted to contain a plurality of implants, said introducer having a distal end insertable into said soft tissue and a proximal end engaging said tubular member;

an obturator slidable within the introducer from said proximal end of said introducer; and

an operating mechanism comprising a shuttle slidable within said tubular member, a trigger mechanism which reciprocally advances said shuttle forward within the tubular member upon each actuation of said trigger mechanism and retracts said shuttle rearward upon each release of said trigger mechanism, and a clutch coupling said obturator to said shuttle as said shuttle advances forward to eject an implant from said distal end of said introducer and decoupling said obturator from said shuttle as said shuttle retracts rearward.

54. The apparatus of claim 53 wherein said introducer has retaining means on said distal end retaining said implants within said introducer but permitting said implants to be pushed out of said distal end of said introducer by advancement of said obturator forward within said introducer.

55. The apparatus of claim 54 wherein said retaining means comprises at least one generally longitudinal slit in said distal end of said introducer forming a split end which is crimped.

56. The apparatus of claim 55 wherein said retaining means further comprises a double chamfer on said split end of said introducer forming a pair of pointed ends which are crimped.