Tissue separation cannula

• US 5,976,168 A
• Filed: 02/22/1999
• Issued: 11/02/1999
• Est. Priority Date: 07/13/1995
• Status: Expired due to Term

• Current Assignee: Maquet Cardiovascular LLC (Getinge AB)
• Original Assignee: Origin Medsystems Inc. (Boston Scientific Corporation)
• Inventors: Chin, Albert K.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): Shai, Daphna
• Application Number:
  US09/255,075
• Time in Patent Office: 253 Days
• Field of Search: 606/190, 606/192, 606/194, 606/207
• US Class Current: 606/190
• CPC Class Codes: A61B 17/00008 Vein tendon strippers tube strippers A61M1/83
• 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 17/11 for performing anastomosis; Buttons for anastomosis
• CPC Class Codes: A61B 17/320016 Endoscopic cutting instruments, e.g. arthroscopes, resectoscopes A61B10/0233, A61B17/29, A61B17/3207 take precedence
• 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 2017/00243 cardiac
• CPC Class Codes: A61B 2017/00473 Distal part, e.g. tip or head A61B2017/00464 takes precedence
• CPC Class Codes: A61B 2017/00969 used for transplantation
• CPC Class Codes: A61B 2017/320044 Blunt dissectors blunt suture needles A61B2017/06085
• CPC Class Codes: A61B 2017/320048 Balloon dissectors
• CPC Class Codes: A61B 90/36 Image-producing devices or illumination devices not otherwise provided for
• CPC Class Codes: A61B 90/361 Image-producing devices, e.g. surgical cameras

Abstract

A cannula includes a tubular body having a proximal end and distal blunt end, at least one lumen extending the length of the body, an endoscope having a lighted, viewing end disposed in the lumen near the distal end of the body, and a transparent, tissue-separating tip substantially covering the distal end of the body. The tissue-separating tip is slightly blunted to inhibit avulsion of tissue and lateral vessels along the dissected cavity formed thereby. Endoscopic viewing through the tip is enhanced by tapering the inner walls thereof to a cusp adjacent the blunt tip in order to reduce visual distortion. Alternatively, a cannula includes a dissection probe and a removable or deflectable tip for exposing the probe and endoscope to facilitate viewing and the dissection of connective tissue and lateral vessels along the dissected cavity. Methods of using such cannulas produce an elongated cavity along the course of a blood vessel for subsequent harvesting or other treatment of the isolated blood vessel. The dissection probe includes a partial ring that is substantially coaxially aligned with the generally cylindrical body of the cannula for passing along the vessel and past lateral branching vessels, and that is manipulatable at the distal end of the cannula in view of the endoscope which visualizes through the transparent tip. Where the vessel is an artery, an initial incision is made, for example, above the superior epigastric artery and the overlying tissue is bluntly dissected down to the superior epigastric artery to establish an initial portion of an elongated working cavity of bluntly-dissected tissue. Lateral arterial branches are doubly clipped or otherwise doubly occluded, and then severed to isolate the artery for use in revascularizing the coronary artery, for example, by transection of the superior epigastric or internal mammary artery and attachment of the transected end to the coronary artery downstream of a significant stenotic occlusion.

Claims

1. A cannula for dissecting an elongated cavity in tissue particularly along a course of a vessel, the cannula comprising:

a tubular body having a proximal end and a distal end;

at least one lumen extending within the length of the body for slidably receiving therein an endoscope having a viewing end to be disposed within the lumen near the distal end of the body; and

a transparent tissue separating member disposed at the distal end of the body and having a conically tapered outer surface converging toward a blunt tip disposed forward to the distal end of the body for directly contacting tissue, the member having substantially rigid and non-collapsible walls and having an internal surface that converges to a sharp point at a location substantially aligned with the at least one lumen to position a viewing end of an endoscope disposed within the one lumen for visualization with reduced distortion.

2. A cannula according to claim 1 in which the tissue separating member is selectively detachable from the distal end of the body.

3. A cannula according to claim 1 in which the tissue separating member encloses the distal end of the tubular body.

4. A cannula according to claim 1 in which the conically tapered outer surface to the blunt tip is about 0.5 inches in length.

5. A cannula according to claim 1 in which the dimension of the member at the distal end of the tubular body is about 8 millimeters.

6. A cannula according to claim 1 in which the outer surface of the tissue separating member forms a tapered outer surface converging toward a blunt tip having a radius of curvature substantially in the range of from approximately 0.030 inches to approximately 0.100 inches.

7. A cannula according to claim 6 in which the outer surface of the tissue separating member forms a blunt tip having a radius of curvature of approximately 0.045 inches.