Iliosacral screw fixation for pelvic obliquity in neuromuscular scoliosis. A long-term follow-up study.

STUDY DESIGN: This was a retrospective review of a consecutive series of patients with neuromuscular spinal deformity who underwent posterior fusion and pelvic fixation using a long construct and an iliosacral screw.

OBJECTIVES: To evaluate the risks and benefits of iliosacral screw fixation.

SUMMARY OF BACKGROUND DATA: Neuromuscular scoliosis with pelvic obliquity poses one of the most challenging instrumentation problems, mainly because of the poor bone quality frequently found within the sacrum. Complications include failure of instrumentation, loss of sacral fixation, loss of lumbar lordosis, and a high rate of nonunion.

METHODS: One hundred fifty-four patients with neuromuscular scoliosis and pelvic obliquity underwent posterior arthrodesis with pelvic fixation using an iliosacral screw. Anteroposterior scoliosis Cobb angle, frontal pelvic obliquity, and sacral inclination angle were measured before surgery, immediately after surgery, and at the 5-year and 3-month follow-up examination. Influence of etiology, severity of deformity, and associated anterior release at the scoliotic curve above also were assessed.

RESULTS: Correction of scoliosis Cobb angle ranged from 53% to 70%, and loss of correction ranged from 3% to 14% at the last follow-up examination. Correction of pelvic obliquity ranged from 60% to 84%, and loss of correction was mild. Sacral inclination angle approached normal values in all patients, except for those with myelomeningocele who had preoperative pelvic retroversion. Loss of correction ranged from 0.3 degree to 5.4 degrees at the last follow-up examination. Complications and loss of correction mostly were encountered in patients with myelomeningocele and spinal muscular atrophy.

CONCLUSIONS: Iliosacral screw fixation in neuromuscular scoliosis is technically standardized and easy and offers mechanically efficient and stable fixation.