Radiographic Evaluation of Percutaneous Pedicle Screw Constructs Including Minimally Invasive Facet Fusions for Unstable Spinal Column Injuries

Presented at SMISS Annual Forum 2016
By Daniel Cavanaugh MD
With Kelley Banagan MD, Tristan Weir BS, Eugene Koh MD, PhD, Daniel Gelb MD, Steven Ludwig MD, Luke Brown MD,

Disclosures: Daniel Cavanaugh MD None Kelley Banagan MD None, Tristan Weir BS None, Eugene Koh MD, PhD B; Biomet: Paid Consultant., Daniel Gelb MD A; AOSpine North America: faculty at courses. D; Advanced Spinal Intellectual Property(ASIP). F; Depuy-Synthes Spine: IP royalties, paid presenter or speak, Globus Medical: IP Royalties., Steven Ludwig MD A; AO Spine North America Spine Fellowship Support: Research Support, PCORI Grant: Submitted, Cervical Spine Research Society: Board or committee member, Journal of Spinal Disorders and Techniques, Th, Luke Brown MD None,

Introduction

Open pedicle screw fixation and fusion has been the traditional treatment for operative spine fractures; recent studies have challenged the need for fusion in the setting of adequate fixation, demonstrating comparable results without fusion. Percutaneous treatment of spine fractures has been demonstrated to have decreased blood loss, operative time, and post-operative pain, but fixation of traumatic injuries without fusion raises the concern for maintainence of correction and failure of the instrumentation secondary to stress fatigue.

Aims/Objectives

The purpose of this study was to compare the maintenance of correction of unstable, thoracolumbar spine fractures treated with percutaneous fixation with and without facet fusion (+FF and -FF). 

Methods

We conducted an IRB approved retrospective review of all thoracic and lumbar spine fractures at our Level 1 trauma center from 2006 to 2013 treated with percutaneous fixation. All patients treated had unstable fractures which would otherwise require open operative intervention. No postoperative bracing was employed. 87 patients had adequate postoperative radiographic follow-up. Initial post-operative and follow-up radiographs were analyzed using the lateral Cobb angle for progressive kyphosis and loss of correction. We also examined each radiograph for IF or IL (greater than 2 mm of radiolucency around any screw). 

Results

The mean follow-up was 33 weeks. There average kyphosis progression was 3.2 degrees. There were no cases of IF during this follow-op period. The rate of IL was 24%. There was no significant difference in the rate of loosening or progression of kyphosis between patients who had facet fusion or not. There was no difference in the percentage of screw pullout between groups. A total of 19 patients (22%) eventually underwent instrumentation removal, of which, only 2 constructs were loose (10.5%). 

Conclusions

Percutaneous fixation of thoracic and lumbar injuries was adequate to prevent progression of kyphosis and allow for fracture healing with or without facet fusion. We found a significantly higher rate of IL (24%) than previously reported in the liturature. However, the clinical significance of this IL remains unclear since the majority of instrumentation removals were performed as routine secondary procedures early in the series, rather than for symptoms.