System for sacroiliac joint fusion

Abstract

A system for preparing the sacroiliac (SI) joint for an SI joint fusion, and optionally delivering an implant to the SI joint, is described herein. The implant is inserted via an inferior inlet approach. A sliding joint finder is inserted into the joint, followed by insertion of a working cannula. The working cannula is operatively coupled to the sliding joint finder, in that it is configured to fit over the sliding joint finder, allowing subsequent removal of the sliding joint finder, and providing a hollow cavity for joint fusion preparation, decortication and insertion of an implant. This system and method provides a less invasive and safer approach for fixing an SI joint or delivering an implant to the SI joint than currently available methods.

We claim: 
     
         1 . A surgical system for preparing the sacroiliac (SI) joint for a fusion, comprising a sliding joint finder and a working cannula
 a) wherein the sliding joint finder comprises
 i) a central axis with a hole that runs the length of the sliding joint finder; 
 ii) a unilateral shelf located on the outer surface of the sliding joint finder; and 
   b) wherein the working cannula comprises a body having a central axis that runs the length of the body,
 wherein the body comprises a distal end, a proximal end and a cavity that is positioned along the central axis and has suitable dimensions for sliding the working cannula over the sliding joint finder. 
   
     
     
         2 . The surgical system of  claim 1 , further comprising an implant insertion tool, wherein the implant insertion tool comprises an elongated body and a slidable insertion ram,
 wherein the body of the insertion tool comprises an insertion region and an insertion end, and a central cavity that runs along a central axis,   wherein the slidable insertion ram comprises a body portion located in the central cavity and in slidable relation thereto, and   wherein the insertion region and insertion end have suitable dimensions for insertion of a spacer into the working cannula.   
     
     
         3 . The system of  claim 1 , wherein the hole that runs the length of the sliding joint finder has suitable dimensions to slide over and allow for removal of wire or pin. 
     
     
         4 . The system of  claim 1 , wherein the sliding joint finder has two lateral sides, and wherein the unilateral shelf of the sliding joint finder is located on only one of the lateral sides at a suitable location for contacting a shelf on the ilium, when it is inserted into the SI joint with the lateral side facing the ilium. 
     
     
         5 . The system of  claim 1 , wherein the working cannula further comprises a unilateral shelf at its proximal end. 
     
     
         6 . The system of  claim 5 , wherein the longer of the two protrusions of the working cannula is configured to fit into the superior end of the SI Joint and the shorter of the two protrusions is configured to fit into the inferior end of the SI joint. 
     
     
         7 . The system of  claim 1 , wherein the insertion end of the body of the insertion tool comprises a flexible tab that can be deformed to retain one or more implants within the insertion end. 
     
     
         8 . The system of  claim 7 , wherein the slidable insertion ram of the implant insertion tool is configured to push the implant(s) out of the insertion end and into the joint, when the insertion ram moves from a retracted position to an operative position. 
     
     
         9 . The system of  claim 7 , wherein the insertion end of the implant insertion tool comprises a cavity configured to retain an implant, when the tab is deformed. 
     
     
         10 . The system of  claim 6 , further comprising one or more spacers. 
     
     
         11 . The system of  claim 10 , wherein the one or more spacers is formed from a material selected from the group consisting of allograft, autograft bone, biocompatible metal, polymers, ceramics, and other synthetic materials. 
     
     
         12 . The system of  claim 1 , wherein the cavity of the working cannula has a substantially straight lateral walls. 
     
     
         13 . The system of  claim 1 , further comprising one or more tools for preparing the SI Joint selected from the group consisting of drill guides and joint box chisels, wherein each of the tools has a proximal end, and wherein each of the tools has suitable dimensions for the proximal end of the tool to be inserted into the working cannula. 
     
     
         14 . The system of  claim 1 , wherein the distal end of the working cannula is configured to receive a lateral guide for fixation elements. 
     
     
         15 . A method of guiding an implant into the SI joint using the system of  claim 1 , comprising:
 a) accessing the joint with a wire or pin;   b) orienting the sliding joint finder over the wire or pin and sliding it into the joint until the unilateral shelf contacts the shelf of the ilium;   c) inserting the working cannula over the sliding joint finder until the distal end of the working cannula reaches the distal end of the sliding joint finder; and   d) removing the sliding joint finder and wire or pin, wherein the working cannula remains in the SI joint.   
     
     
         16 . The method of  claim 15 , wherein the method further comprises after step (d),
 e) inserting into the cavity of the working cannula, an implant insertion tool comprising one or more implants in its insertion end,   wherein the implant insertion tool comprises an elongated body and a slidable insertion ram,   wherein the body of the insertion tool comprises an insertion region and an insertion end, and a central cavity that runs along a central axis, and   wherein the slidable insertion ram comprises a body portion located in the central cavity and in slidable relation thereto.   
     
     
         17 . The method of  claim 16 , further comprising pushing the slidable insertion ram from a retracted position to an operative position, wherein the slidable insertion ram comprises a proximal end that contacts a posterior surface of the implant, and wherein the implant pushes the tab and the proximal end of the ram pushes the implant into the prepared SI joint. 
     
     
         18 . The method of  claim 15 , wherein the approach is an inferior inlet approach.