Outcomes of Decompression and Stabilization with a Pedicle-Based Semirigid Posterior Stabilization System in the Lumbar Spine

Introduction Patients with lumbar spinal stenosis who do not respond satisfactorily to nonoperative measures may require decompression. Laminectomies/decompression without instrumentation may cause instability and associated symptoms. Fusion often involves multiple segments potentially increasing the risk of proximal junctional kyphosis (PJK), adjacent segment disease (ASD), and surgical morbidity of lateral exposure to prepare fusion bed. We have therefore been using the TRANSITION Stabilization System (Globus Medical, Inc., Audubon, Pennsylvania, United States) to provide stability without fusion at the operated levels. Following insertion of pedicle screws, to which the rod is attached, a semirigid rod is custom built along a central cord using a combination of rigid screw head attachments, flexible spacers, and a compressible bumper. Biomechanical studies have indicated superior performance to other similar systems. We report our clinical results. Patients and Methods A retrospective analysis of prospectively collected data was performed for patients who underwent surgery between September 2011 and December 2013. Outcome measures included Oswestry Disability Index (ODI), Visual Analog Scale (VAS) back/leg pain, Hospital Anxiety and Depression Scale, and complications. Statistical analysis was performed with paired and unpaired tests. Results Demographics: Data were available for 24 patients; 8 females and 16 males. Mean age at surgery was 66.8 years. Mean body mass index was 30.4 kg/m2. Mean length of follow-up was 44 (range, 10–109) weeks. Mean postoperative length of stay was 7.2 days, and when those patients requiring reoperation for complications were excluded it was 4.4 days. Surgery: A total of 10 L3–S1, 4 L4–S1, 1 L4–L5, 3 L2–L5, 4 L3–L5, 1 L1–L5, and 1 L2–S1 stabilizations were performed with a variety of combined central and foraminal decompressions. Mean blood loss was 648 mL and surgical time 176 minutes. Eight patients sustained intraoperative dural tears that were sealed with fibrin sealant. Outcomes: Mean ODI improved from 45.1 to 31.3 ( p = 0.001), VAS back from 6.7 to 3.7 ( p ≤ 0.01), VAS legs from 6.7 to 2 ( p ≤ 0.01), anxiety from 6.1 to 5.4 ( p = 0.37), and depression from 7.3 to 3.7 ( p = 0.033). There was no statistical correlation between pre- and postoperative ODI, VAS back or legs, depression/anxiety scores, and demographics. Reoperations: There were three early reoperations: one patient for discharging wound with positive microbiology and for revision of a screw, one patient for discharging wound with negative microbiology, and one patient for revision of a screw. There were no implant failures or revisions for PJK or ASD to date. Conclusion Our results using the TRANSITION Stabilization System suggests that pedicle-based semirigid posterior stabilization systems warrant further consideration as a potential tool in providing satisfactory early postoperative results while potentially reducing the long-term morbidity associated with fusions for lumbar stenosis. We would encourage further research to assess longer term results and radiographic outcomes.