Methods of use of an exchange system for soft tissue access pathway

Abstract

Disclosed are surgical tools, tool sets and methods for percutaneously accessing and preparing treatment sites within the spine for subsequent treatment procedures. The treatment site may be an inter-vertebral motion segments in the lumbar and sacral regions of the spine. The tool set may comprise introducer tools and bone dilators for accessing and tapping into a targeted site, such as, for example, the anterior surface of the S1 vertebral body. The tool set may also comprise cutters and extractors for preparing the treatment site for subsequent treatment procedures. The tool set may additionally comprise a bone graft inserter, an exchange system, and/or a temporary distraction tool for further preparing the treatment site for subsequent treatment procedures.

1 . An exchange system for increasing the cross sectional area of an access pathway through soft tissue and bone, comprising:
 an elongate, tubular exchange bushing, having a proximal end, a distal end and a central lumen extending therethrough;   an elongate, tubular exchange cannula, having a proximal end, a distal end and a central lumen extending therethrough, the exchange bushing being axially slideable within the central lumen of the exchange cannula; and   a plurality of distally extending fingers on the distal end of the exchange cannula, the fingers movable between a first, reduced outside diameter configuration and a second, enlarged outside diameter configuration.   
   
   
       2 . An exchange system as in  claim 1 , wherein the exchange bushing comprises a recess for receiving the fingers when in the first, reduced outside diameter. 
   
   
       3 . An exchange system as in  claim 1 , wherein the plurality of fingers are generally triangular in shape. 
   
   
       4 . An exchange system as in  claim 1 , wherein the first, reduced outside diameter configuration is a closed configuration comprised of the plurality of fingers congregated about a central axis forming a conical tip. 
   
   
       5 . An exchange system as in  claim 1 , wherein the second, enlarged outside diameter configuration is an open configuration. 
   
   
       6 . An exchange system as in  claim 1 , wherein the exchange bushing comprises a taper toward the distal end of the exchange bushing. 
   
   
       7 . An exchange system as in  claim 6 , wherein the exchange bushing comprises a tapered tip at the distal end of the exchange bushing. 
   
   
       8 . An exchange system as in  claim 7 , wherein the tapered tip comprises a first tapered angle toward a longitudinal axis of the exchange bushing and a second tapered angle away from the longitudinal axis of the exchange bushing. 
   
   
       9 . An exchange system as in  claim 8 , wherein the tapered tip comprises a third tapered angle toward the longitudinal axis of the exchange bushing. 
   
   
       10 . An exchange system as in  claim 1 , further comprising a handle on the proximal end of the exchange cannula. 
   
   
       11 . An exchange system as in  claim 10 , wherein the handle comprises an annular band. 
   
   
       12 . An exchange system as in  claim 1 , further comprising an indicium of the rotational orientation of the bevel. 
   
   
       13 . An exchange system as in  claim 12 , wherein the indicium comprises a visible marker on the proximal end of the exchange cannula. 
   
   
       14 . An exchange system as in  claim 13 , wherein the indicium comprises at least one notch on an annular band carried by the proximal end of the exchange cannula. 
   
   
       15 . A method of increasing the cross sectional area of an access pathway through soft tissue and bone, comprising:
 forming a bore in a sacrum;   inserting an exchange system into the bore, the exchange system comprising an elongate, tubular exchange cannula seated on the outside of an elongate, tubular exchange bushing, the exchange bushing having a proximal end, a distal end and a central lumen extending therethrough, the exchange cannula having a proximal end, a distal end and a central lumen extending therethrough, the exchange bushing being axially slideable within the central lumen of the exchange cannula, the distal end of the exchange cannula comprising a plurality of distally extending fingers, the fingers movable between a first, reduced outside diameter configuration and a second, enlarged outside diameter configuration;   advancing the exchange cannula distally in to the bore; and   withdrawing the exchange bushing proximally out of the bore.   
   
   
       16 . The method as in  claim 15 , further comprising moving the fingers of the exchange cannula in to the bore. 
   
   
       17 . The method as in  claim 15 , further comprising inserting a dilator sheath into the bore. 
   
   
       18 . The method as in  claim 15 , further comprising inserting a device distally into the central lumen of the exchange cannula. 
   
   
       19 . The method as in  claim 18 , wherein the inserting the device distally into the central lumen of the exchange cannula radially outwardly displaces fingers of the exchange cannula to create a pathway that has a diameter large enough to accommodate the passage of the device, while isolating the working channel from adjacent organs or anatomical structures.