Surgical access device including variable length cannula

Abstract

A surgical access device includes a cannula having a variable length. The cannula may include a shaft assembly including an outer shaft, an intermediate shaft disposed within and longitudinal slidable relative to the outer shaft, and an inner shaft disposed within and longitudinal slidable relative to the intermediate shaft. The shaft assembly is movable between an unextended position, a fully extended position, and a semi-extended position between the unextended and fully extended positions. The cannula may include a shaft having annular folds formed therein. The annular folds are axially movable relative to each other such that the shaft is longitudinally movable between an unextended position and a plurality of extended positions.

What is claimed is: 
     
         1 . A surgical access device comprising:
 a cannula including a shaft assembly, the shaft assembly including:
 an outer shaft; 
 an intermediate shaft disposed within and longitudinal slidable relative to the outer shaft; and 
 an inner shaft disposed within and longitudinal slidable relative to the intermediate shaft, 
   the shaft assembly movable between an unextended position, a fully extended position, and a semi-extended position between the unextended and fully extended positions.   
     
     
         2 . The surgical access device according to  claim 1 , wherein the inner shaft is movable within the intermediate shaft between a proximal-most position and a distal-most position and the intermediate shaft is movable within the outer shaft between a proximal-most position and a distal-most position and wherein, when the shaft assembly is in the unextended position, the inner and intermediate shafts are in the proximal-most positions and when the shaft assembly is in the fully extended position, the inner and intermediate shafts are in the distal-most positions. 
     
     
         3 . The surgical access device according to  claim 2 , wherein, when the shaft assembly is in the semi-extended position, the inner shaft is in the proximal-most position and the intermediate shaft is in the distal-most position. 
     
     
         4 . The surgical access device according to  claim 1 , wherein a distal end portion of the outer shaft includes an annular ridge on an inner surface thereof and the intermediate shaft includes proximal and distal annular grooves defined in an outer surface thereof, and wherein, when the shaft assembly is in the unextended position, the annular ridge of the outer shaft is engaged with the distal annular groove of the intermediate shaft and, when the shaft assembly is in the semi-extended and fully extended positions, the annular ridge of the outer shaft is engaged with the proximal annular groove of the intermediate shaft. 
     
     
         5 . The surgical access device according to  claim 1 , wherein a distal end portion of the intermediate shaft includes an annular ridge on an inner surface thereof and the inner shaft includes proximal and distal annular grooves defined in an outer surface thereof, and wherein, when the shaft assembly is in the unextended and semi-extended positions, the annular ridge of the intermediate shaft is engaged with the distal annular groove of the inner shaft and, when the shaft assembly is in the fully extended position, the annular ridge of the intermediate shaft is engaged with the proximal annular groove of the inner shaft. 
     
     
         6 . The surgical access device according to  claim 1 , further including a first gasket disposed between the intermediate and outer shafts and a second gasket disposed between the inner and intermediate shafts. 
     
     
         7 . The surgical access device according to  claim 1 , further including a balloon operably associated with the cannula. 
     
     
         8 . The surgical access device according to  claim 7 , wherein a proximal portion of the balloon is secured to the outer shaft of the shaft assembly and a distal portion of the balloon is secured to the inner shaft of the shaft assembly. 
     
     
         9 . The surgical access device according to  claim 7 , wherein an inflation channel is defined in an outer surface of the outer shaft of the shaft assembly, the inflation channel in fluid communication with the balloon. 
     
     
         10 . The surgical access device according to  claim 9 , further including an anchor inflation port coupled to the outer shaft of the shaft assembly and in fluid communication with the inflation channel of the outer shaft. 
     
     
         11 . The surgical access device according to  claim 1 , further including an instrument housing coupled to the cannula. 
     
     
         12 . The surgical access device according to  claim 11 , wherein the instrument housing is secured to the outer shaft of the shaft assembly of the cannula. 
     
     
         13 . The surgical access device according to  claim 1 , further including a retention collar movably positioned along the shaft assembly of the cannula. 
     
     
         14 . A surgical access device comprising:
 a cannula including a shaft defining an access lumen therethrough, the shaft having annular folds formed therein, the annular folds axially movable relative to each other such that the shaft is longitudinally movable between an unextended position and a plurality of extended positions.   
     
     
         15 . The surgical access device according to  claim 14 , wherein the annular folds are formed in a central portion of the shaft. 
     
     
         16 . The surgical access device according to  claim 15 , wherein the central portion of the shaft extends a majority length of the shaft. 
     
     
         17 . The surgical access device according to  claim 15 , wherein the shaft includes proximal and distal end portions having fixed lengths. 
     
     
         18 . The surgical access device according to  claim 14 , wherein the annular folds includes alternating inner and outer fold peaks and, wherein, the outer fold peaks are spaced a first axial distance relative to each other when the shaft is in the unextended position and a second axial distance relative to each other when in the shaft is in one of the plurality of extended positions, the second axial distance being greater than the first axial distance. 
     
     
         19 . The surgical access device according to  claim 18 , wherein the outer fold peaks are pointed for tissue fixation. 
     
     
         20 . The surgical access device according to  claim 14 , further including an instrument housing coupled to the cannula.