Posterior Transpedicular Fibular Grafts and Interferential Screws for the Surgical Treatment of L5-S1 Spondyloptosis: Case Report of Four Patients With 8.5 Years' Follow-Up.

Abstract

Retrospective case series. To present long-term results using partial reduction and instrumented fusion adding an L5-S1 transpedicular fibular plus interferential screw construct to treat spondyloptosis. Several techniques have been described to treat high-grade spondylolisthesis. Reported complications include neurologic injuries, pseudarthrosis, slip progression, and instrumentation failure. We present a posterior-only approach with partial reduction and instrumentation to treat spondyloptosis. Interbody fusion is provided by fibular struts inserted through the S1 pedicles capturing L5, avoiding neural manipulation. Graft stress is supported using interferential screws placed through these same pedicles. Retrospective revision of 4 cases with grade V spondylolisthesis. Information analyzed was preoperative, postoperative, and final follow-up clinical and radiographic data, with final Scoliosis Research Society Questionnaire-22 outcomes. Pelvic incidence, sacral slope, pelvic tilt, L5 incidence, lumbar lordosis, L5 slip angle, lumbosacral angle, and sagittal vertical axis were measured. Fusion and complications were recorded. Mean age was 25.7 ± 5.7 years. All men with isthmic spondyloptosis (Meyerding V; type 5/6, Spinal Deformity Study Group classification). There were 3 primary surgeries and 1 revision. Median fused levels were 2 (range, 2-2.75); mean operative time was 6.1 ± 0.8 hours and median transfusion units were 2 (percentile 2-5). Mean follow-up was 102 months (range, 24-157 months). Postoperative pain using Visual Analog Score decreased from 7.1 ± 2.4 to 1.3 ± 1.3. Pelvic tilt improved 9.7°, whereas L5 incidence improved 15° and lumbosacral angle and L5 slip angle improved over 30°, which was maintained over time. Sagittal vertical axis improved by 1.6 cm; however, the improvement was lost by the final follow-up. The Scoliosis Research Society global satisfaction scale was 4.6 ± 0.2. No major complications were observed. This technique yielded satisfactory clinical results in the treatment of L5-S1 spondyloptosis, resulting in stable anterior support and complete radiographic fusion. It avoided the complications reported from the use of previous posterior techniques such as graft fractures, pseudarthrosis, slip progression, and neurologic injuries.