Growth-sparing spinal instrumentation in skeletal dysplasia

STUDY DESIGN.: Retrospective case series. OBJECTIVE.: To report the outcomes of distraction-based, growth-sparing spinal instrumentation in patients with skeletal dysplasia. SUMMARY OF BACKGROUND DATA.: Patients with skeletal dysplasia with spinal deformity often undergo early fusion, further compromising an already small chest. Nonfusion techniques may provide a safe alternative and allow for thoracic growth. METHODS.: Between 2004 and 2010, 12 children with a diagnosis of various types of skeletal dysplasia underwent growth-sparing spinal instrumentation for severe spinal deformities. The mean duration of treatment with growing rods was 57 months (42-84 mo). Nine patients were treated with growing rods (8 dual, 1 single), and 3 were treated with vertical expandable prosthetic titanium rib (VEPTR; Synthes). Preoperative, initial postoperative, and final follow-up anteroposterior and lateral spine radiographs were measured for magnitude of deformity, junctional kyphosis, and implant failure. RESULTS.: The major curve Cobb angle improved from a mean of 79 preoperatively to a mean of 41 at the last follow-up (52%). There was a decrease in mean thoracic kyphosis from 77 preoperatively to 64 at final follow-up and an increase in mean lumbar lordosis from 58 preoperatively to 63 at final follow-up. The mean space available for the lungs increased by 26 mm on the concave and 24 mm on the convex side. Six patients required revision surgery for proximal junctional kyphosis. There were 4 rod failures and 6 hook and 8 screw dislodgements. One patient with vertical expandable prosthetic titanium rib had failed rib fixation that required revision. CONCLUSION.: Growth-sparing spinal instrumentation in patients with skeletal dysplasia and severe spinal deformity has a high complication and revision rate, and surgeons should closely monitor these patients. The complication rate is comparable with previous reports on patients with other diagnoses. However, deformities were well controlled, some trunk growth was achieved, and fusion surgery was delayed in all cases.