Radiographic Evaluation of Minimally Invasive Instrumentation and Fusion for Treating Unstable Spinal Column Injuries

STUDY DESIGN: Retrospective cohort. OBJECTIVE: Facet fusion in minimally invasive spine surgery (MISS) may reduce morbidity and promote long-term construct stability. The study compares the maintenance of correction of thoracolumbar (TL) trauma patients who underwent MISS with facet fusion (FF) and without facet fusion (WOFF) and evaluates instrumentation loosening and failure. METHODS: TL trauma patients who underwent MISS between 2006 and 2013 were identified and stratified into FF and WOFF groups. To evaluate progressive kyphosis and loss of correction, Cobb angles were measured at immediate postoperative, short-term, and long-term follow-up. Evidence of >2 mm of radiolucency on radiographs indicated screw loosening. If instrumentation was removed, postremoval kyphosis angle was obtained. RESULTS: Of the 80 patients, 24 were in FF and 56 were in WOFF group. Between immediate postoperative and short-term follow-up, kyphosis angle changed by 4.0° (standard error [SE] 1.3°) in the FF and by 3.0° (SE 0.4°) in the WOFF group. The change between immediate postoperative and long-term follow-up kyphosis angles was 3.4° (S.E 1.1°) and 5.2° (S.E 1.6°) degrees in the FF and WOFF groups, respectively. Facet fusion had no impact on the change in kyphosis at short term (P = .49) or long term (P = .39). The screw loosening rate was 20.5% for the 80 patients with short-term follow-up and 68.8% for the 16 patients with long-term follow-up. There was no difference in screw loosening rate. Fifteen patients underwent instrumentation removal—all from the FF group. CONCLUSION: FF in MISS does not impact the correction achieved and maintenance of correction in patients with traumatic spine injuries.