Insulated Pedicle Access System and Related Methods

Abstract

A pedicle access system including a cannula, a stylet, and a removable T-handle. The pedicle access system may be used to percutaneously approach the pedicle, initiate pilot hole formation, and conduct a stimulation signal to the target site for the purposes of performing a pedicle integrity assessment during the pilot hole formation. To do this, the cannula and stylet are locked in combination and inserted through an operating corridor to the pedicle target site, using the T-handle to facilitate easy movement and positioning of the cannula/stylet combination. A stimulation signal may be applied during pilot hole formation to conduct the pedicle integrity assessment. In a significant aspect, the T-handle may be detached from the cannula/stylet combination to facilitate the use of various surgical tools as necessary.

We claim: 
     
         1 . A method comprising:
 making an insulated pedicle access system available for use, the insulated pedicle access system including:
 a stylet having a handle and a needle attached to the handle; and 
 a cannula coupled to the handle such that the needle extends through the cannula; 
   advancing a distal end of the insulated pedicle access system into a bone as part of forming a pilot hole;   after the advancing, unlocking the stylet from the cannula; and   after the unlocking removing the stylet from the cannula while leaving the cannula positioned in the pilot hole.   
     
     
         2 . The method of  claim 1 , further comprising:
 deploying a guide wire into the pilot hole through the cannula;   after deploying the guide wire, removing the cannula; and   advancing a pedicle screw along the guide wire and into the bone.   
     
     
         3 . The method of  claim 1 , further comprising:
 placing an electrical stimulation source in electrical communication with the needle; and   delivering an electrical stimulation current from the electrical stimulation source to monitor integrity of the bone.   
     
     
         4 . The method of  claim 1 , wherein prior to unlocking the stylet from the cannula:
 two or more protrusions of the stylet resist movement of the cannula relative to the stylet in a direction parallel to a length of the cannula.   
     
     
         5 . The method of  claim 1 , wherein the insulated pedicle access system further includes:
 a lock collar having:
 an interior lumen; 
 a first set of protrusions extending into the interior lumen; and 
 a second set of protrusions extending into the interior lumen; 
   
     
     
         6 . The method of  claim 5 , wherein unlocking the stylet from the cannula includes:
 manipulating the lock collar such that the first and second set of protrusions transition from engaging with engagement tabs to no longer engaging with the engagement tabs.   
     
     
         7 . The method of  claim 6 ,
 wherein the engagement tabs extend perpendicularly from the handle.   
     
     
         8 . The method of  claim 1 , wherein making an insulated pedicle access system available for use includes assembling the insulated pedicle access system. 
     
     
         9 . The method of  claim 8 , further comprising:
 inserting the needle into the cannula such that a coupler of the cannula enters a space defined by the stylet handle and medial indentations of the handle are aligned with but not yet engaging the coupler.   
     
     
         10 . The method of  claim 9 , further comprising:
 manipulating a lock collar such that the medial indentations engage with the coupler.   
     
     
         11 . A method comprising:
 making a stylet available for use, the stylet comprising:
 a needle a proximal region and a distal region, the distal region including a shaped tip; 
 a handle portion connected to the needle; and 
 at least two engagement tabs extending from the handle portion, 
   making a cannula available for use, the cannula comprising:
 an elongated shaft having a proximate end and a distal end and an interior lumen; and 
 a coupling element positioned at the proximate end of the elongated shaft, the coupling element having a proximal region and a distal region, wherein the proximal region including an engagement region, wherein the at least two engagement tabs are dimensioned to receive the cannula coupling element engagement region, and wherein the engagement tabs have one or more protrusions the one or more protrusions having geometry complementary to the shape of the engagement region; 
   decoupling the stylet from the cannula such that the one or more protrusions cease resisting movement of the engagement region relative to the stylet in a direction parallel to the stylet's length;   after decoupling the stylet from the cannula, removing the stylet from the cannula;   inserting a guide wire through the cannula; and   after inserting the guide wire, advancing a pedicle screw along the guide wire and into the bone.   
     
     
         12 . The method of  claim 11 , further comprising:
 assembling an insulated pedicle access system by inserting the needle into the cannula; and   advancing the insulated pedicle access system into a bone as part of forming a pilot hole.   
     
     
         13 . The method of  claim 11 , further comprising:
 placing an electrical stimulation source in electrical communication with the needle; and   delivering an electrical stimulation current from the electrical stimulation source to monitor bone integrity.   
     
     
         14 . A method comprising:
 advancing a distal portion of an insulated pedicle access system into a bone as part of forming a pilot hole; and   unlocking a stylet of the insulated pedicle access system from a cannula of the pedicle access system; and   removing the stylet from the cannula while leaving the cannula positioned in the pilot hole.   
     
     
         15 . The method of  claim 14 , further comprising:
 deploying a guide wire into the pilot hole through the cannula;   after deploying the guide wire, removing the cannula; and   advancing a pedicle screw along the guide wire and into the bone.   
     
     
         16 . The method of  claim 14 , further comprising:
 placing an electrical stimulation source in electrical communication with the stylet; and   delivering an electrical stimulation current from the electrical stimulation source to the bone to monitor integrity the bone.   
     
     
         17 . The method of  claim 14 , wherein prior to unlocking the stylet from the cannula:
 two or more protrusions of the stylet resist movement of the cannula relative to the stylet in a direction parallel to a length of the cannula.   
     
     
         18 . The method of  claim 14 , wherein the insulated pedicle access system further includes:
 a lock collar having:
 an interior lumen; 
 a first set of protrusions extending into the interior lumen; and 
 a second set of protrusions extending into the interior lumen; 
   
     
     
         19 . The method of  claim 18 ,
 wherein unlocking the stylet from the cannula includes manipulating the lock collar such that the first and second sets of protrusions transition from engaging with engagement tabs to no longer engaging with the engagement tabs; and   wherein the engagement tabs extend perpendicularly from the handle.   
     
     
         20 . The method of  claim 14 , further comprising:
 prior to advancing the distal portion, inserting the needle into the cannula such that a coupler of the cannula enters a space defined by the stylet handle and medial indentations of the handle are aligned with but not yet engaging the coupler; and   manipulating a lock collar such that the medial indentations engage with the coupler.