SPINAL DEFORMITY IN MYELODYSPLASIA - CORRECTION WITH POSTERIOR PEDICLE SCREW INSTRUMENTATION

Study Design. A retrospective review of transpedicular instrumentation used in a series of 24 patients with myelodysplastic spinal deformiti es and deficient posterior elements. Objective. To describe the useful ness and efficacy of : these instruments in the treatment of complicat ed myelodysplastic spinal deformity. Methods. The mean preoperative sc oliosis was 75.7 degrees (range, 39-130 degrees) in the 22 patients wi th scoliotic deformities; 4 patients with thoracic hyperkyphoses avera ged 70.5 degrees (range, 46-90 degrees) and 10 patients with lumbar ky phoses averaged 80.5 degrees (range, 42-120 degrees). The instrumentat ion extended to the sacrum in 4 patients and the pelvis in 9; 10 patie nts also underwent anterior release and fusion and 7 underwent concomi tant spinal cord detethering. At an average follow-up of 4.0 years (2. 0-7.7 years; one patient died at 8 months), all patients have fused (w ith the exception of two lumbosacral pseudarthroses). Results. At last follow-up, deformity measured 32.1 degrees scoliosis (range, 6-85 deg rees), 30.8 degrees thoracic kyphosis (ranger 24-35 degrees), and 0.0 degrees lumbar kyphosis (range, 35 degrees kyphosis to 29 degrees lord osis). Three patients lost some neurologic function after surgery; two recovered within 6 months and one has incomplete recovery. No ambulat ory patient lost the ability to walk. Five patients required additiona l surgical procedures; in three cases, there was instrumentation break age associated with pseudarthrosis or unfused spinal segments. Conclus ions. Pedicle screw instrumentation is uniquely suited to the deficien t myelodysplastic spine. Compared with historical control subjects, th ese devices have proven capable of significant correction of both scol iotic and kyphotic deformities. This instrumentation appears particula rly useful in preserving lumbar lordosis in all patients and may prese rve more lumbar motion in ambulatory myelodysplasia patients.