Method and apparatus for dissecting tissue layers

Abstract

A retractor for use in arthroscopic surgery. The retractor has a mechanical expanding portion for expanding against sub-surface tissues when the retractor is in use. The retractor also has a fluid-operated expanding portion, which may be independently controllable, for expanding against sub-surface tissues when the retractor is in use. The retractor is inserted through a small percutaneous opening, expanded in sub-surface tissues without significantly damaging the tissue, then collapsed after use for removal. The retractor can be manipulated to allow the surgeon to push or pull or lever on tissue. The retractor can be hollow like a cannula to permit the passage of one or more surgical devices through the retractor, with a side portal into the center of the retractor.

What is claimed:  
     
         1 . A method of maintaining separation between first and second tissue layers, comprising the steps of: 
 a) separating the first tissue layer from the second tissue layer;    b) introducing an inflatable chamber between the first and second tissue layers with the chamber in a collapsed condition, wherein the inflatable chamber includes a first sheet having a first outer periphery and a second sheet having a second outer periphery sealingly attached to the first outer periphery, wherein each of the first outer periphery and the second outer periphery is generally trapezoidal; and    c) inflating the inflatable chamber after the introducing step.    
     
     
         2 . The method of  claim 1 , wherein the first outer periphery has a fist edge and a second edge longer than the first edge, and wherein the inflatable chamber includes a throughhole positioned closer to the first edge than the second edge.  
     
     
         3 . The method of  claim 1 , wherein the first outer periphery has a first linear edge and a second linear edge longer than the first linear edge, and wherein the inflatable chamber includes a throughhole positioned closer to the first linear edge than to the second linear edge.  
     
     
         4 . The method of introducing an instrument into a working space in a patient, comprising the steps of: 
 a) cutting an incision in the patient;    b) dissecting a first tissue layer from a second tissue layer;    c) inserting an inflatable chamber between the first and second tissue layers, the inflatable chamber having a deflated condition and an inflated condition, the inflatable chamber being inserted between the first and second tissue layers in the deflated condition, the inflatable chamber including a first sheet having a first outer periphery and a second sheet having a second outer periphery sealingly attached to the first outer periphery, wherein the first outer periphery has a first extended portion and a second extended portion defining a space therebetween;    d) inflating the inflatable chamber after the inserting step; and    e) introducing an instrument into the working space through the space between the first extended portion and the second extended portion.    
     
     
         5 . A method of maintaining separation between first and second tissue layers, comprising the steps of: 
 a) separating the first tissue layer from the second tissue layer;    b) introducing an inflatable chamber between the first and second tissue layers with the chamber in a collapsed condition, wherein the inflatable chamber includes a first sheet having a first outer periphery and a second sheet having a second outer periphery sealingly attached to the first outer periphery, wherein each of the first outer periphery and the second outer periphery has three convex portions and a non-convex portion between each pair of the convex portions; and    c) inflating the inflatable chamber after the introducing step.    
     
     
         6 . A method of maintaining separation between first and second tissue layers, comprising the steps of: 
 a) separating the first tissue layer from the second tissue layer;    b) introducing an inflatable chamber between the first and second tissue layers with the chamber in a collapsed condition, wherein the inflatable chamber includes a first sheet having a first outer periphery and a second sheet have a second outer periphery sealingly attached to the first outer periphery, wherein each of the first outer periphery and the second outer periphery is bilaterally symmetrical about an axis, and each of the first outer periphery and the second outer periphery has a first generally triangular wing portion on another side of the axis, wherein the first outer periphery has a first curved edge and a second curved edge longer than the first curved edge, and wherein of the first general triangular wings portion and the second general triangular wing portion has an edge coinciding with a portion of the second curved edge; and    c) inflating the inflatable chamber after the introducing step.