Treatment catheters with thermally insulated regions

• US 20020082556A1
• Filed: 11/13/2001
• Published: 06/27/2002
• Est. Priority Date: 11/13/2000
• Status: Active Grant

• Current Assignee: Wit Ip Corporation
• Original Assignee: Wit Ip Corporation
• Inventors: Cioanta, Iulian, Klein, Richard Barry, Lazarovitz, Jacob
• Granted Patent: US 6,758,857 B2
• Time in Patent Office: Days
• US Class Current: 604/113
• CPC Class Codes: A61B 18/04 by heating by applying electromagnetic radiation A61B18/18; hyperthermia using electric or magnetic fields, radiation or ultrasound A61N
• CPC Class Codes: A61B 2017/00274 Prostate operation, e.g. prostatectomy, turp, bhp treatment
• CPC Class Codes: A61B 2017/22069 Immobilising; Stabilising
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61B 2018/046 in liquid form
• CPC Class Codes: A61F 7/123 using a flexible balloon containing the thermal element
• CPC Class Codes: A61M 2210/166 Prostate
• CPC Class Codes: A61M 31/00 Devices for introducing or retaining media, e.g. remedies, in cavities of the body A61M25/00 takes precedence ; introducing or retaining ophthalmic products into the ocular cavities A61F9/0008

Abstract

Flexible treatment catheters are configured to be inserted into a body lumen or cavity to deliver heated fluid through at least one fluid lumen therein to thermally treat or ablate a targeted site in a biological subject. The flexible treatment catheters can include improved thermally insulated regions comprising a mixture formed of liquid elastomeric (such as a polyurethane) mixture (which transitions to a solid state) and miniaturized hollow plastic bodies positioned between the outer wall of the treatment catheter and the fluid lumen. The thermally insulated region is configured such that, measured ex vivo, the treatment catheter can present a maximum temperature of below about 45° C. on the external surface of the outer wall of the treatment catheter when the treatment catheter circulates fluid having an inlet temperature of above or between about 60°-62° C. Alternatively or additionally, the treatment catheter can include an elongated insert positioned in a catheter fluid lumen to inhibit the closure of the lumen after exposure to fluids in the treatment catheter at temperatures sufficient to thermal ablate targeted tissue over a thermal ablation treatment period. The treatment catheter can include a urinary drainage lumen with an elongated insert frictionally engaged therewith, the drainage lumen and insert are configured to provide a fluid volume throughput through the drainage lumen of greater than about 20-25 ml/min during and after (for about 12-72 hours after) a thermal ablation session.

Claims

1. A treatment catheter configured for insertion into a body cavity or lumen of a biological subject, said treatment catheter comprising:

a flexible elongated tubular body having a thin outer wall with an external surface and at least one fluid lumen axially extending therein, wherein said tubular body comprises a region having increased thermal insulation relative to another region thereof, said increased thermal insulation region configured to encase said at least one fluid lumen therein, said at least one fluid lumen extending a length along said tubular body, wherein said increased thermal insulation region comprises a plurality of segments defining spaces having associated perimeter shapes radially extending between said at least one fluid lumen and said outer wall, wherein at least one of said plurality of segment spaces has a perimeter shape with at least one edge portion which is arranged so that said perimeter shape radially tapers into said edge portion as it approaches at least one of said at least one fluid lumen and said outer wall such that said at least one said edge portion is oriented to reside proximate to one of said outer wall and said at least one fluid lumen to define a contact point thereat.

2. A treatment catheter according to claim 1, wherein a plurality of said segments are at least partially filled with a non-gaseous insulative material.

3. A treatment catheter according to claim 1, wherein a quantity of insulating material is introduced into at least some of said segments in a flowable state, and subsequently takes on a non-flowable state prior to insertion into the body lumen.

4. A treatment catheter according to claim 3, wherein, in operation during use, said insulating material is held captured in a solidified state in said segments.

5. A treatment catheter according to claim 4, wherein said insulating material comprises polyurethane and hollow microspheres.

6. A treatment catheter according to claim 4, wherein said microspheres are plastic, and wherein said insulating material comprises at least 10% volume of hollow plastic microspheres.

7. A treatment catheter according to claim 1, wherein said plurality of segments have perimeters with polygonal shapes with a plurality of edge portions.

8. A treatment catheter according to claim 7, wherein a plurality of said polygonal segments are oriented such that each has a selected edge portion which defines the forwardmost contact point for said segment shape with one of said outer wall and said fluid lumen.

9. A treatment catheter according to claim 8, wherein a plurality of said segment spaces have a substantially triangulated shaped perimeter shape with three edge portions, and wherein at least one of said substantially triangulated perimeter shapes is oriented such that one of its edge portions resides proximate said outer wall to define a contact point thereat and a different one of said triangulated perimeter shapes is oriented such that one of its edge portions resides proximate one of said inner fluid lumens to define a contact point thereat.

10. A treatment catheter according to claim 1, wherein said at least one fluid lumen is a plurality of inner fluid lumens, at least one of which is a drainage lumen configured to drain body fluids therein.

11. A treatment catheter according to claim 10, wherein a plurality of said plurality of segment spaces have a substantially triangulated shaped perimeter shape with three edge portions, wherein at least one of said substantially triangulated perimeter shapes is oriented such that one of its edge portions resides proximate said outer wall to define a contact point thereat and a different one of said triangulated perimeter shapes is oriented such that one of its edge portions resides proximate one of said inner fluid lumens to define a contact point thereat.

12. A treatment catheter according to claim 11, wherein said plurality of inner fluid lumens further include at least one circulating fluid inlet lumen, and at least one circulating fluid outlet lumen.

13. A treatment catheter according to claim 12, wherein said circulating fluid inlet lumen, said circulating fluid outlet lumen and said drainage lumen are configured in cross-section to extend from a common center toward said outer wall as substantially equally divided pie shaped lumens.

14. A treatment catheter according to claim 11, wherein said circulating fluid inlet lumen, said circulating fluid outlet lumen and said drainage lumen are configured in cross-section as four separated quadrants, said drainage lumen occupying two of said four quadrants.

15. A treatment catheter according to claim 11, wherein said tubular body has a longitudinally extending center axis and wherein in cross-section, said common center is offset from the center axis such that said drainage lumen is more closely positioned to said outer wall than said inlet and outlet circulating lumens.

16. A treatment catheter according to claim 11, wherein said at least one fluid lumen is a plurality of fluid lumens, including at least one inlet and outlet fluid circulating lumens, and wherein said segments are circumferentially spaced about the perimeter of said inlet and outlet fluid lumens.

17. A treatment catheter according to claim 16, wherein said triangulated perimeter shaped spaces are positioned to reside intermediate said outer wall and said inlet and outlet fluid lumens, and wherein said segments terminate into a unitary material layer at locations about said tubular body.

18. A treatment catheter according to claim 1, further comprising an inflatable treatment balloon positioned about a peripheral distal portion of said elongated tubular body such that said treatment balloon is expandable to a configuration which extends radially outward a distance from said outer wall external surface of said tubular body, wherein said at least one fluid lumen is a plurality of lumens all axially extending within said tubular body such that said plurality of lumens are encased by said outer wall and, for at least a portion of the length of a more proximal portion of said tubular body relative to said treatment balloon, said plurality of fluid lumens are encased by outer wall and said increased thermal insulation region, wherein said plurality of lumens include a circulating fluid inlet lumen, a circulating fluid outlet lumen, and a drainage and fluid delivery lumen, and wherein said fluid inlet and outlet lumens are in fluid communication with said treatment balloon and are configured, in operation, to cause said treatment balloon to expand.

19. A treatment catheter according to claim 18, further comprising an inflatable anchoring balloon, and wherein said tubular body includes at least one inflation path in fluid communication with said inflatable anchoring balloon on one end and which is engageable with an externally located inflation source during operation, and wherein said inflation path is formed as a through passage in said thermal insulation region.

20. A treatment catheter according to claim 1, wherein said at least one fluid lumen includes a fluid drainage and delivery lumen for draining body fluids therethrough, and wherein said tubular body is sufficiently conformable to yield to the contours of the subject'"'"'s body as it is inserted therein, yet sufficiently rigid to maintain said drainage and delivery lumen in an open condition having an opening size sufficient to allow fluid flow therethrough of at least about 20 ml/min when in position and exposed to tissue which is exhibiting distress during or subsequent to undergoing a treatment therapy.

21. A treatment catheter according to claim 1, wherein selected surfaces of said catheter includes anti-microbial coatings thereon.

22. A treatment catheter according to claim 1, wherein selected surfaces of said catheter includes anti-inflammatory medicaments formed thereon, which, in position, are released into the subject'"'"'s body.

23. A treatment catheter according to claim 1, wherein said at least one fluid lumen includes at least one drainage and fluid delivery lumen with a flexibly configured wall, and said catheter further comprises an elongated insert disposed in said drainage and delivery lumen to provide increased structural rigidity to said lumen wall inhibit the collapse of said drainage and delivery lumen.

24. A treatment catheter according to claim 1, wherein said outer wall includes a hydrophilic coating thereon.

26. A treatment catheter according to claim 25, wherein said plurality of segments have perimeters with polygonal shapes.

27. A treatment catheter according to claim 26, wherein a plurality of said polygonal segments are oriented such that each has a selected edge portion which defines the forwardmost contact point for said segment shape with one of said outer wall and said fluid lumen.

28. A treatment catheter according to claim 26, wherein a plurality of said segments have a substantially triangulated shaped perimeter shape with three edge portions.

29. A treatment catheter according to claim 28, wherein a plurality of said segments have a substantially triangulated shaped perimeter shape with three edge portions, and wherein at least one of said substantially triangulated perimeter shapes is oriented such that one of its edge portions resides proximate said outer wall to define a contact point thereat and a different one of said triangulated perimeter shapes is oriented such that one of its edge portions resides proximate one of said inner fluid lumens to define a contact point thereat.

30. A treatment catheter according to claim 25, wherein a plurality of said segments comprise an insulating material held therein.

31. A treatment catheter according to claim 30, wherein said insulating material comprises polyurethane and hollow microspheres.

32. A treatment catheter according to claim 31, wherein said microspheres are plastic, and wherein said insulating material comprises at least 10% volume of hollow plastic microspheres.

25. A treatment catheter configured for insertion into a body cavity or lumen of a biological subject, said treatment catheter comprising:

a flexible elongated tubular body having a thin outer wall with an external surface and at least one fluid lumen axially extending therein, and a plurality of segments having associated perimeter shapes radially extending between said at least one fluid lumen and said outer wall, said fluid lumen axially extending a length along said tubular body, wherein at least one of said plurality of segments has a perimeter shape with at least one edge portion which is arranged so that said perimeter shape radially tapers into said edge portion as it approaches at least one of said at least one fluid lumen and said outer wall such that said at least one said edge portion is oriented to point toward and reside proximate to one of said outer wall and said at least one fluid lumen to define a contact point thereat.

33. A treatment catheter configured for insertion into a body cavity or lumen of a biological subject, said treatment catheter comprising:

a flexible elongated tubular body having an outer wall with an external surface and at least one fluid lumen axially extending therein, wherein said tubular body comprises a region having increased thermal insulation relative to another region thereof, said increased thermal insulation region configured to encase said at least one fluid lumen therein, said at least one fluid lumen extending a length along said tubular body, wherein said increased thermal insulation region comprises a liquid elastomeric material which is introduced into said catheter such that it is captured between said outer wall and said at least one fluid lumen and then solidified therein prior to use.

34. A treatment catheter according to claim 33, wherein said increased thermal insulation region is defined by said outer wall, a plurality of void spaces interposed between said outer wall and the inner wall of said at least one fluid lumen, and wherein said liquid elastomeric material is introduced into selected ones of said void spaces.

35. A treatment catheter according to claim 34, wherein at least one of said void spaces has a perimeter with a polygonal shape.

36. A treatment catheter according to claim 35, wherein at least one of said void space perimeters has a substantially triangulated shape.

37. A treatment catheter according to claim 34, wherein at least one of said void spaces has a perimeter with a substantially circular shape.

38. A treatment catheter according to claim 34, wherein at least one of said void spaces has a perimeter with a substantially oval shape.

39. A treatment catheter according to claim 33, wherein said liquid elastomeric material comprises hollow microspheres.

40. A treatment catheter according to claim 39, wherein said insulating material comprises at least 10% volume of hollow microspheres.

41. A treatment catheter according to claim 39, wherein said hollow microspheres are hollow plastic microspheres, and wherein said liquid elastomeric material comprises at least one of nylon, polyurethane, polyethylene, silicone.

42. A treatment catheter according to claim 33, wherein said liquid elastomeric material comprises polyurethane.

43. A treatment catheter according to claim 33, further comprising an inflatable treatment balloon positioned about a peripheral distal portion of said elongated tubular body such that said treatment balloon is expandable to a configuration which extends radially outward a distance from said outer wall external surface of said tubular body, wherein said at least one fluid lumen is a plurality of lumens all axially extending within said tubular body such that said plurality of lumens are encased by said outer wall and, for at least a portion of the length of a more proximal portion of said tubular body relative to said treatment balloon, said plurality of fluid lumens are encased by outer wall and said increased thermal insulation region, wherein said plurality of lumens include a circulating fluid inlet lumen, a circulating fluid outlet lumen, and a drainage and fluid delivery lumen, and wherein said fluid inlet and outlet lumens are in fluid communication with said treatment balloon and are configured, in operation, to cause said treatment balloon to expand.

44. A treatment catheter according to claim 43, wherein, in position in a subject, said treatment catheter is configured to circulate a liquid heated external of said tubular body through said inlet lumen to said treatment balloon and out through said outlet lumen, the liquid heated to a temperature sufficient to thermally treat or ablate tissue at a desired biological target site proximate said treatment balloon, and wherein, in operation, said outer surface of said outer wall in said increased thermal insulation region has a temperature which is at or below about 45°

C.

45. A treatment catheter according to claim 44, wherein the temperature of the heated circulating liquid as it enters said inlet lumen of said tubular body is at or greater than about 60°

C., and wherein, measured ex vivo, said external surface of said outer wall about said increased thermal insulation region exhibits a maximum average temperature of about 42-45°

C. after a thermal treatment period of at least 30 minutes.

46. A treatment catheter according to claim 45, wherein said drainage and delivery lumen is centrally disposed within said tubular body, and wherein said inlet and outlet lumens are positioned on opposing sides thereof.

47. A treatment catheter according to claim 33, wherein said at least one fluid lumen comprises at least one drainage and fluid delivery lumen, and wherein said tubular body is sufficiently conformable to yield to the contours of the subject'"'"'s body as it is inserted therein, yet sufficiently rigid to maintain said drainage and delivery lumen in an open condition which is sized at about at least 50-75% of the size of the lumen outside the body before the treatment, when in position in the body and exposed to tissue which is exhibiting distress during or subsequent to a treatment.

48. A treatment catheter according to claim 33, wherein said at least one fluid lumen comprises three lumens, a circulating inlet channel, a circulating outlet channel, and at least one drainage lumen, wherein in cross-section, said three lumens define three substantially equal pie shaped areas extending radially outward from a common center, and wherein said tubular body is sufficiently conformable to yield to the contours of the subject'"'"'s body as it is inserted therein,

49. A treatment catheter according to claim 33, wherein said at least one fluid lumen comprises four lumens, a circulating inlet channel, a circulating outlet channel, and two drainage lumens, wherein in cross-section, said four lumens each occupy a quadrant of a common circle, and wherein said tubular body is sufficiently conformable to yield to the contours of the subject'"'"'s body as it is inserted therein.

50. A treatment catheter according to claim 44, wherein said treatment catheter is sized and configured for insertion into the urethra of a male subject, the urethra generally including, in serial order from the external most portion to the internal portion, the penile meatus, the penile urethra, the bulbous urethra, the sphincter, the membranous urethra, the prostatic urethra, the bladder neck and the bladder, wherein said tubular body is sufficiently conformable to yield to the contours of the subject'"'"'s body as it is inserted therein, yet sufficiently rigid to maintain said drainage and delivery lumen in an open condition sufficient to discharge urine at a flow rate of at least about 20 ml/min when said catheter is in position in the urethra and exposed to prostatic tissue which is exhibiting distress during or subsequent to undergoing a thermal ablation therapy.

51. A treatment catheter according to claim 50, further comprising a anchoring balloon positioned on a distal portion of said tubular body such that it is more distal than said treatment balloon, said anchoring balloon configured and sized such that, when inflated and in position in the biological subject, said anchoring balloon resides against the bladder neck of the subject to position said treatment balloon in the prostate relative to the bladder of the subject, wherein said treatment catheter includes a port on said distal portion thereof in fluid communication with said drainage and delivery lumen to allow urine to drain therethrough.

52. A treatment catheter according to claim 33, wherein said at least one fluid lumen includes at least one drainage and fluid delivery lumen with a flexibly configured elastomeric wall, and said catheter further comprises an elongated insert disposed in said drainage and delivery lumen to provide increased structural rigidity to said lumen wall inhibit the collapse of said drainage and delivery lumen when positioned in the subject and exposed to the body'"'"'s reaction to a therapeutic treatment.

53. A treatment catheter according to claim 33, wherein said treatment balloon comprises a thin wall expandable elastomeric balloon comprising a surface coating comprising ceramic microspheres positioned thereon to enhance the thermal transmissivity of said treatment balloon.

54. A catheter configured for insertion into a body cavity or lumen of a biological subject, said treatment catheter comprising:

a flexible elongated tubular body having a thin outer wall with an external surface;

at least one fluid lumen axially extending within said tubular body such that said at least one lumen is encased by said outer wall; and

an elongated insert sized and configured to be received into said at least one fluid lumen to inhibit the closure of said fluid lumen to allow fluid throughput volumes of at least about 20 ml/min, when in position in the subject, and wherein said elongated insert has increased rigidity compared to said at least one fluid lumen.

55. A catheter according to claim 54, wherein said insert is configured to provide an opening size in said at least one fluid lumen when in the subject and exposed to swelling in a treated region during or after a therapeutic treatment session, which is at least about 50-75% of the opening size prior to introduction into the subject.

56. A catheter according to claim 55, wherein said insert is sized and configured to frictionally engage with said at least one fluid lumen, and wherein said insert is structurally sufficiently rigid to provide the opening size of the fluid lumen after exposure to heated fluid circulating in said catheter at temperatures above about 40-45°

C. for at least about 5-30 minutes.

57. A catheter according to claim 54, wherein said thin outer wall is formed from an elastomeric material, wherein said insert has a contiguous body with a shape which substantially corresponds to the shape of said at least one fluid lumen, and wherein said drainage lumen with said insert allows fluid throughput volumes of above about 25 ml/min after exposure to a temperature of at least about 57°

-62°

C.

58. A catheter according to claim 54, wherein said at least one fluid lumen is a plurality of axially extending fluid lumens, and wherein said catheter further comprises an inflatable treatment balloon positioned about a peripheral distal portion of said elongated tubular body such that said treatment balloon is in fluid communication with at least one of said plurality of fluid lumens such that said treatment balloon is expandable to a configuration which extends outwardly a distance from said outer wall of said tubular body.

59. A catheter according to claim 58, further comprising a thin inner tubular wall spaced apart from said thin tubular outer wall and a plurality of radially extending segments positioned therebetween.

60. A catheter according to claim 59, wherein said plurality of fluid lumens includes a circulating fluid inlet lumen, a circulating fluid outlet lumen, and a drainage and fluid delivery lumen, and wherein said elongated insert is disposed in said drainage and fluid delivery lumen.

61. A treatment catheter according to claim 59 wherein said segments are configured to axially extend a length of said tubular body intermediate said outer wall and said inner walls, and wherein said segments encase a quantity of non-gaseous insulation material to define an insulated region along a proximal portion of said tubular body intermediate said fluid lumens and said outer wall.

62. A catheter according to claim 61, wherein said insulation material is formed by a combination of a liquid elastomeric material and a quantity of hollow elastomeric or plastic microspheres.

63. A catheter according to claim 62, wherein, measured ex vivo, said tubular body external surface about said insulated region exhibits a maximum temperature of about 42°

C. after exposure to a thermal ablation treatment session having an inlet fluid temperature of at least about 57°

-62°

C. as introduced into a proximal portion of said fluid inlet lumen and circulated through said fluid inlet lumen, said treatment balloon, and said fluid outlet lumen for a period of at least 30 minutes.

64. A method of thermally treating a subject, comprising the steps of:

inserting a flexible treatment catheter in the natural lumen or body cavity of a subject;

circulating liquid, heated external of the subject, in the treatment catheter such that it travels, captured in the treatment catheter, to a localized treatment region and exposes targeted tissue to a temperature of above about 45°

C. for a predetermined thermal ablation treatment period;

insulating non-targeted tissue below the targeted region such that the non-targeted tissue is exposed to a maximum temperature of about 42-45°

C. from contact with the external surface of the treatment catheter during said circulating step;

draining body fluids through the treatment catheter during said circulating step, wherein said treatment catheter is configured in a manner which allows a drainage volume of above about 20 ml/min after said circulating step and before said removing step; and

removing the treatment catheter after an initial healing period of about 12-72 hours.

65. A method according to claim 64, wherein said circulating liquid is heated to about 60°

-62°

C. external of the subject and directed into the treatment catheter at an inlet temperature of about 62°

C., and wherein said method further comprises the step of terminating the circulation of the heated liquid after the thermal ablation treatment period.

66. A method according to claim 64, wherein said treatment catheter includes a flexible drainage lumen with an elongated insert disposed therein, said elongated insert configured to inhibit the closure of the drainage lumen and to facilitate increased urine flow rates after said exposing and directing steps.

67. A method according to claim 64, wherein said treatment catheter includes an outer wall with an external surface and a plurality of insulation lumens disposed internally thereof, said plurality of insulation lumens defining void spaces therein arranged in abutting contact about a perimeter of said treatment catheter to encase the heated circulating fluid therewithin, and wherein said plurality of insulation lumens comprise a non-gaseous insulation material held within said void spaces.

68. A method according to claim 64, wherein said insulation material comprises an initially liquid polyurethane mixed with micron sized hollow plastic or elastomeric bodies which subsequently solidifies in said plurality of lumens.

69. A method according to claim 64, wherein said elongated insert is assembled to said catheter by introducing a planar stylet therein and inserting the stylet and insert into the selected fluid lumen and removing the stylet leaving the insert frictionally engaged with the inner wall of said selected fluid lumen.

70. A method of inhibiting the closure of a flexible thin walled lumen in a catheter configured for insertion into a lumen or cavity of a biological subject, comprising the steps of:

providing a flexible elongated catheter such that it is sized for insertion into a natural body lumen or cavity of a biological subject and such that it can bend to follow the contour of the body lumen or cavity, the flexible catheter comprising at least one fluid channel therein; and

positioning an elongated insert into the at least one fluid channel such that it axially extends along a length thereof, the elongated insert configured to maintain an open fluid channel during and after the flexible catheter delivers a thermal therapy to a desired target site in the biological subject.

71. A method according to claim 70, wherein the elongated insert is formed of PTFE.

72. A method according to claim 70, wherein the open fluid channel is sufficiently configured and sized to allow a fluid flow rate therethrough of at least about 25 ml/min. after exposure to temperatures of above about 45°

C. after a thermal treatment period of at least about 30 minutes.

73. A method for providing increased thermal insulation in a treatment catheter having at least one fluid lumen therein, the treatment catheter having an outer wall which encases the at least one fluid lumen therein, the treatment catheter being configured to deliver a thermal or thermal ablation treatment to a target site in a natural lumen or body cavity of a biological subject, the method comprising the steps of:

introducing a quantity of liquid insulation mixture into a desired region of the treatment catheter such that it is held intermediate the at least one fluid lumen and the outer surface of the treatment catheter; and

allowing the liquid mixture to harden to a non-liquid state to define a thermally insulated region in the catheter.

74. A method according to claim 73, wherein the treatment catheter has an elongated tubular body, and wherein the treatment catheter further comprises a plurality of axially extending insulation lumens circumferentially arranged to encase the at least one fluid lumen below the outer wall, and wherein said introducing step comprises the step of inserting the liquid insulation mixture into the plurality of insulation lumens.

75. A method according to claim 74, wherein the liquid insulation mixture comprises liquid polyurethane.

76. A method according to claim 75, wherein the liquid insulation mixture further comprises hollow plastic or elastomeric microspheres.