Method for use of dilating stylet and cannula
In one preferred aspect, a method is provided for inserting an instrument set having a tapered configuration into a patient. In another preferred aspect, a method is provided for inserting a cannula having an external threaded portion into bone. In yet another preferred aspect, a method is provided for forming and enlarging an opening in bone.
1. A method for forming an opening into bone, the method comprising:
providing a cannula having a distal end, a proximal end, a length therebetween, a passage along the length, and an exterior surface, the exterior surface including a thread along at least a portion of the length of the cannula, the thread having a low profile to facilitate linear insertion of the thread into the bone;
inserting the cannula through the bone by linear insertion with the bone sliding over the thread without significant engagement of the thread with the bone to a depth in the bone proximate to a final insertion depth; and
further advancing the cannula into the bone by rotating the cannula to engage the thread of the cannula to the bone until the cannula is at the final depth of insertion, the cannula being in fixed relationship to the bone.
2. The method of claim 1 , wherein the further advancing the cannula includes engaging the thread of the cannula with a vertebra of the human spine.
3. The method of claim 1 wherein the inserting includes inserting more than half of the length of the cannula into the bone before the step of further advancing the cannula.
4. The method of claim 1 , wherein the providing includes providing a cannula having a plurality of serrations, and the inserting step includes cutting the bone with the serrations.
5. The method of claim 1 , further comprising inserting a bone displacement instrument through the cannula and displacing bone proximate the distal end of the cannula.
6. The method of claim 1 , further comprising delivering a material through the cannula.
7. The method of claim 6 , wherein the material includes bone cement.
8. The method of claim 1 , wherein the cannula provided includes a window between the distal end and the thread.
9. The method of claim 8 , further comprising inserting an instrument into the cannula and displacing bone through the window with the instrument.
10. The method of claim 1 , wherein the cannula provided has a central longitudinal axis and the furthest extent of the distal end along the length has a perimeter surrounding the central longitudinal axis that is in a plane perpendicular to the central longitudinal axis.