[Neuromuscular deformity of the pelvis and its surgical treatment]

Abstract

Purpose of the study: To evaluate the efficacy of surgical treatment in pelvic deformities associated with neuromuscular spine deformity, using radiographic parameters and clinical outcome analysis. In the lumbo-pelvic region, spinal deformity is most frequently combined with pelvic obliquity, lumbar hyperlordosis, hip deformity and leg-length discrepancy. Pelvic deformities include an excessive posterior or anterior pelvic tilt, obliquity or rotation and windblown hip syndrome.

Material and methods: In the period from 1994 to 2006, 42 paediatric patients (28 girls and 14 boys) underwent surgical correction of spine and pelvic deformities by the Luque-Galveston technique. The group included 25 patients with an underlying diagnosis of a spastic form of cerebral palsy, seven patients affected by paralysis, six with Duchenne muscular dystrophy and four with spinal muscular atrophy. The average age at the time of surgery was 14 years and 3 months and the patients were followed- up for 7 years and 5 months on the average. The results were evaluated on the basis of findings on antero-posterior and lateral radiographs including the pelvis, hip joints and the whole spine. The patients were examined before surgery, then immediately after it, and at yearly follow-up intervals.

Results: The mean pre-operative pelvic obliquity was 37 degrees (+/-6.0) and it improved to 9 degrees (+/-4.5) post-operatively. Horizontalization of the sacrum was corrected from the mean preoperative value of 19 degrees (+/-5.0) to 37 degrees (+/-6.1) post operatively. This difference was statistically significant (p=0.001). Scoliosis curve correction achieved by the surgery was from 79 degrees (+/-21.3) pre-operatively to 35 degrees (+/-14.5) post-operatively, with a mean correction rate of 56 %. The following complications were recorded: faulty insertion of the pelvic fixation resulting in perforation of the medial cortical substance of the iliac crest in one patient, pseudoarthrosis in the region of thoraco-lumbal junction in two patients, instrumentation failure with the need of pseudoarthrosis resection and re-instrumentation in one patient, and deep infection requiring wound irrigation and longterm antibiotic therapy.

Discussion: The surgical correction of pelvic deformity is always associated with operative treatment of scoliosis. However, the procedure is regularly preceded by surgical correction of muscular imbalance of the lower limbs and pelvis and of hip deformities. The surgical stabilization of spinal and pelvic deformities brings about the loss of some alternative motor stereotypes. This disadvantage is compensated for by a better sitting stability and better prospects for prosthetic care.

Conclusions: The radiographic and clinical findings in the patients treated showed good correction of pelvic deformities in the frontal and sagittal planes. Pelvic obliquity correction thus contributes to the improvement of sitting stability in physically disabled patients.