505 - Translaminar Facet Screws Percutaneous Approach - Surgical Technique a...

#505 Translaminar Facet Screws Percutaneous Approach - Surgical Technique and Clinical Results

MIS Techniques and Outcomes

Poster Presented by: J.G.D.P.V Wanderley

Author(s):

J.G.P.V. Wanderley (1)
F. Nigri (2)

(1) Fundação Educacional Serra dos Órgãos, Neurosurgery, Teresópolis, Brazil
(2) Rio de Janeiro University, Neurosurgery, Rio de Janeiro, Brazil

Abstract

Introduction/Goal: Magerl in 1983 showed a very elegant technique that allowed us to achieve a safe and efficient spinal segment fixation with a new screw trajectory, based on Boucher"s transfacet screw technique, but without the risk of break the facet joint, the translaminar facet screw fixation (TFSF).

Despite the clinical and biomechanical success rates this concept was not so spreaded as the pedicle screws constructions.

Currently with the big appeal for MIS techniques, Boucher´s and Magerl´s concepts are emerging again.

The goal of this paper is to show a new percutaneous surgical technique based on a pre op plan and fluoroscopy guidance and a simple free hand navigation system, and also its clinical applications.

Material and Methods: 20 males and 20 females lumbar CT scans were analized with a radiological software the Osirix to determine the 3 parameters necessary for the TFSF: the lateral and caudal angle and the distance away from the midline.

This datas were collected to achieve average measurements for each of them.

We also performed a radilogical study with a contrasted lumbar spinal model to determine the ideal anatomical landmarks for the screw trajectory in the lateral, AP, obliques and outlet spine fluo views.

From January 2011 to January 2013 38 patients underwent surgical procedures combined with TFSF unilaterally or bilaterally.

24 patients combined with contralateral Tlif plus pedicle screws, 4 stand alone to treat canal stenosis and 10 combined with Xlif.

Results: The CT scan study achieved an average 40 grades lateral angle, and 30 grades caudal angle from L1/L2 to L4/L5. The distance away from the midline average was 60 mm. We didn´t studied the level L5/S1 because this is not a good indication for translaminar facet screws and better for transfacet screws.

We utilized a radiological classification criteria showed by Rick Sasso in his paper published in The Spine Journal 2005, about the Percutaneous Computer Assisted Translaminar Facet Screw.

0 - screw completely in the bone

I - < 1/2 screw out of bone

II - > 1/2 screw out of bone

III - screw completely out of bone.

Our Results: grade 0 - 92%, grade I -5.2%, grade II - 2,8 and zero grade III.

The single revision surgery is the grade II screw that broken in the 60 day pos op and was revised keeping the screw in and pedicle screws fixation through a Wiltse approach.

Conclusion: The TFSF is a safe, efficient and reproducible technique even in a percutaneous approach without complex navigation systems.

It can be performed stand alone mainly in elderly patients with severe DDD and canal stenosis or combined with contralateral TLIF plus pedicle screws, Xlif in prone or lateral position and ALIF.