Sacroiliac joint fusion alignment guide

Abstract

A device and method for defining a trajectory for instruments in a sacroiliac joint fusion procedure employs a handle and two movable guidance arms that are separated by an adjustable distance. The first guidance arm has a substantially straight pronged distal end terminating in a first prong, a second prong and a space between the first prong and second prong defining a first point in a straight trajectory for inserting screws into a sacroiliac joint. The guidance arm forms a receiving bore on a distal end thereof to define a second point in the trajectory. The pronged distal end is inserted through a posterior incision in the patient into a cored-out sacroiliac joint, with the second guidance arm outside the body, and the orientation of the alignment guide is adjusted by pivoting the alignment guide about the pronged distal end to determine a suitable trajectory. Instruments and implements are placed along the trajectory and guided by the alignment guide to drill screw holes and insert screws used in the sacroiliac joint fusion procedure into the screw holes.

1 . A sacroiliac joint fusion alignment guide, comprising: 
 a handle;    a first guidance arm connected to the handle having a substantially straight pronged distal end terminating in a first prong, a second prong and a space between the first prong and second prong defining a first point in a straight trajectory for inserting screws into a sacroiliac joint; and    a second guidance arm coupled to the first guidance arm forming a receiving bore on a distal end thereof to define a second point in the trajectory.    
   
   
       2 . The sacroiliac joint fusion alignment guide of claim i, wherein the receiving bore has an open bottom end.  
   
   
       3 . The sacroiliac joint fusion alignment guide of  claim 1 , wherein the distance between the first guidance arm and the second guidance arm is adjustable.  
   
   
       4 . The sacroiliac joint fusion alignment guide of  claim 1 , wherein the first guidance arm includes a proximal engagement end bent away from the distal end for coupling to the second guidance arm.  
   
   
       5 . The sacroiliac joint fusion alignment guide of  claim 1 , wherein the second guidance arm includes a proximal engagement end comprising a slot configured to receive the proximal engagement end of the first guidance arm.  
   
   
       6 . The sacroiliac joint fusion alignment guide of  claim 5 , wherein the proximal engagement end of the first guidance arm includes flanges configured to engage side recesses in the slot of the second guidance arm.  
   
   
       7 . The sacroiliac joint fusion alignment guide of  claim 5 , wherein the proximal engagement end of the second guidance arm includes bent away from the distal end.  
   
   
       8 . The sacroiliac joint fusion alignment guide of  claim 5 , wherein the proximal engagement end of the first guidance arm includes a threaded hole for receiving a threaded distal end of the handle to couple the handle to the first guidance arm.  
   
   
       9 . The sacroiliac joint fusion alignment guide of  claim 1 , wherein the first prong and the second prong on the first guidance arm are tapered and intersect to form a point at the tip of the distal end.  
   
   
       10 . The sacroiliac joint fusion alignment guide of  claim 1 , further comprising an adjustable attachment guide coupled to the second guidance arm spaced from the receiving bore and defining a second trajectory spaced from the first trajectory.  
   
   
       11 . A method of guiding screws into a sacroiliac joint of a patient, comprising the steps of: 
 inserting a distal end of an alignment guide through a posterior incision in the patient into a cored-out sacroiliac joint; and    adjusting the orientation of the alignment guide to determine a suitable trajectory, defined by the alignment guide, for the screws, the trajectory extending from the sacroiliac joint through an iliac crest and out of the patient.    
   
   
       12 . The method of  claim 11  wherein the distal end of the alignment guide is pronged.  
   
   
       13 . The method of  claim 11 , wherein the alignment guide is adjusted in multiple degrees of freedom to select a suitable trajectory.  
   
   
       14 . The method of  claim 11 , further comprising moving the distal end of the alignment guide within the sacroiliac joint to select a suitable trajectory.  
   
   
       15 . The method of  claim 11 , further comprising the step of adjusting a distance between two guidance arms on the alignment guide to accommodate patient anatomy.  
   
   
       16 . The method of  claim 11 , further comprising the step of inserting a guidewire along the trajectory defined by the alignment guide, such that the guidewire extends from the sacroiliac joint along the trajectory and out of the patient.  
   
   
       17 . The method of  claim 16 , wherein the step of inserting the guidewire comprises the steps of: 
 inserting an obturator through a receiving bore on a guidance arm on the alignment guide, wherein the receiving bore aligns with the pronged distal end to define the trajectory;    inserting the guidewire through the obturator; and    removing the obturator from the alignment guide; and    removing the alignment guide, leaving the guidewire extending from the sacroiliac joint along the trajectory and out of the patient.    
   
   
       18 . The method of  claim 16 , further comprising the step of drilling a screw hole into the sacroiliac joint following the trajectory using a cannulated drill inserted over the guidewire.  
   
   
       19 . The method of  claim 18 , further comprising the step of inserting a screw into the drill hole.  
   
   
       20 . A method of guiding screws into a sacroiliac joint of a patient, comprising the steps of: 
 providing an alignment guide comprising a first guidance arm having a distal end defining a first portion of a trajectory and a second guidance arm having a distal end defining a second portion of the trajectory;    adjusting the distal end of the second guidance arm in t multiple degrees of freedom to adjust the trajectory; and    using the alignment guide to insert screws along the trajectory and into the sacroiliac joint.    
   
   
       21 . The method of  claim 20 , wherein the step of using the alignment guide to insert screws comprises the steps of: 
 inserting the distal end of the first guidance arm into the sacroiliac joint, such that the distal end engages a sacrum and provides the trajectory extending from the sacroiliac joint through an iliac crest;    passing a guidewire through the distal ends of the first and second guidance arms into the ilium and across the sacroiliac joint, such that the guidewire extends along the trajectory.    
   
   
       22 . The method of  claim 21 , further comprising the steps of: 
 drilling a screw hole into the sacroiliac joint following the trajectory using a cannulated drill inserted over the guidewire; and    inserting a screw into the screw hole.    
   
   
       23 . The method of  claim 20 , wherein the alignment guide contacts bone of the sacroiliac joint at the distal end of the first guidance arm and is allowed to pivot freely around the distal end of the first guidance arm to determine a proper trajectory.