The "slide technique": an improvement on the "funnel technique" for safe pedicle screw placement in the thoracic spine.

Abstract

Technical note. To report and describe a new free-hand technique for pedicle screw placement in the thoracic spine especially in severe deformities. Because of distortion of anatomic landmarks scoliosis, this free-hand placement technique based on pedicle access through the decancelled transverse process is a safe procedure. Transverse process is widely exposed and its posterior cortex is decorticated. The cancellous bone content of the transverse process is completely removed using a small curette. Bone wax is applied to avoid local bleeding and then the decancelled transverse process is inspected. The entry of the pedicle is then easily identified by the presence of remaining cancellous bone. A pedicular probe is then inserted and gently advanced. During pedicle probe insertion, the cortex of the anterior aspect of transverse process and the lateral margin of the pedicle act as a "slide" to permit safe insertion of the instrument. In our experience, no patient required additional procedures for screw revision, and no neurologic deficit occurred stemming from malpositioning of pedicle screws. The key point of the "slide technique" is to use the cortex of the anterior aspect of transverse process and the lateral margin of the pedicle as a "slide" to permit correct probe positioning during pedicle probe insertion. This technique is very close to the "funnel technique". The "funnel" and then the "slide" technique are mostly useful in complex spinal deformities as in neuromuscular patients. The "slide technique" is a safe, effective and cost-effective technique for pedicle screw placement in the thoracic spine especially in severe deformities. IV.