Long-Term Outcomes of High Grade Pediatric Spondylolisthesis Treated with Posterolateral Fusion and Fibular Dowel Grafting
Method: Average age was 13.5 years (range 11-17 years). All patients had both back and bilateral leg pain. 5 patients had Meyerding grade III spondylolisthesis, 12 had grade IV, and 5 had spondyloptosis. No patient had undergone prior surgery. All patients had posterolateral fusion with iliac crest grafting; 8 patients had pedicle screw instrumentation. Allograft fibular dowels were placed via a posterior approach from the sacrum to L5. Average follow-up was 8.6 years (range 3-17 years).
Results: Clinical outcome was assessed with a specific questionnaire addressing relief of back and leg pain, improvement in quality of life, and achievement of pre-operative expectations. Parameters measured were Meyerding grade, slip angle, sacral inclination, lumbar lordosis, and pelvic incidence. Radiographs evaluated posterolateral fusion mass, integrity of the fibular dowel, and hardware failure if present. 86% of patients had good or excellent relief of back pain, while 91% had good or excellent relief of leg pain. 95% of patients reported improvement in quality of life and 91% felt their pre-operative expectations had been achieved. 91% of patients had solid posterolateral fusion by 6 months. Fracture of a fibular dowel occurred in one case. Hardware failure occurred in one case. Pedicle screw instrumentation did not affect clinical or radiographic outcome. 3 patients (14%) required further surgery; two with a symptomatic pseudarthrosis underwent supplemental posterolateral fusion and a third had elective removal of painful, loose hardware.
Conclusion: Transient L5 neuropraxia occurred in 4 cases but no persistent neurologic deficits were noted. Lumbar lordosis improved an average of 6 degrees. Slip angle, sacral inclination, slip grade and pelvic incidence were not found to significantly affect clinical outcome.