SINGLE STAGE POSTERIOR UNIT ROD CORRECTION FOR NEUROMUSCULAR SCOLIOSIS: CLINICAL AND RADIOGRAPHIC OUTCOMES

L. Erik Westerlund. MD;
Sanjitpal Gill MD;
Todd Jarosz MD;
John Blanco MD;
Mark Abel MD
Dept of Orthopaedic Surgery, University of Virginia, Charlottesville, VA, USA

The purpose of this investigation was to evaluate the objective outcomes of single–stage posterior spinal fusion using the unit rod with Luque–wiring and Galveston technique for the definitive management of neuromuscular scoliosis in the skeletally immature patient. Specific attention was directed to the identification of crankshafting, curve correction. pelvic obliquity. and maintenance of correction.

Twenty–eight patients with neuromuscular spinal deformity underwent the index procedure from 1991 to 1997. All patients were treated with posterior spinal fusion and instrumentation from the upper thoracic region to the pelvis utilizing a unit rod construct with Luque–wiring and Galveston technique. No anterior procedures were performed. Patients were assessed both radiographically and by serial clinical exam over a mean of 58 months (range, 27–96 months). Detailed measurements from pre–operative. post–operative. and most recent radiographs included Cobb angle, rib– vertebral angle difference [RVAD], pelvic obliquity, Risser sign, and triradiate cartilage status. Measures were compiled to quantitate objective outcome.

One patient died of causes unrelated to the surgery, leaving twenty–seven patients to comprise the study group. The average age of the patients was 12.75 years (range, 6–19yrs). There were six males and twenty–one females. The underlying diagnosis was CP in 21, with mixed other diagnoses comprising the remainder of the group. Twenty–six patients were skeletally immature at surgery: 20 were Risser 0 or 1 and the remainder Risser 2. The pre–operative Cobb angle averaged 66.9 degrees (range 33 –94 degrees), while the most recent Cobb angle averaged 25.9 degrees (range, 10 to 50). Pre–.operative RVAD averaged 52.8 degrees (range, 18–95 degrees), and most recent RVAD measures averaged 21.9 (range. 0–70 degrees). Pelvic obliquity averaged 20.0 degrees pre–operatively (range, 18–95), and 5.1 degrees (range,0–15) post–operatively, and 5.9 degrees (range, 0–30) at most recent follow–up. Windshield effect was noted at the pelvic insertion of the unit rods in 5 patients. Complications included late infection in 3 patients necessitating eventual hardware removal; significant loss of curve correction was only noted in these 3 patients. Evidence of crankshaft phenomenon was seen radiographically in 1 case with no clinical significance.

Though anterior surgery may be required to facilitate correction of severe, rigid curves, our results demonstrate that single–stage posterior spinal unit–rod instrumentation and fusion is effective in obtaining and maintaining alignment in the skeletally immature patient with neuromuscular scoliosis. The achieved correction is well maintained with this technique, thus avoiding the incumbent risks and morbidity associated with the addition of an anterior procedure.