Study design: Retrospective analysis of patients with spinal muscular atrophy (SMA) treated with growing rod (GR) instrumentation for scoliosis.
Objective: To evaluate structural effectiveness, complications, and length of hospital stay associated with GRs for scoliosis in SMA and to compare values with those of infantile and juvenile idiopathic scoliosis (IIS/JIS).
Summary of background data: Most studies evaluate GR effectiveness in all patients. We specifically examined SMA and IIS/JIS.
Methods: We searched a multicenter database and found 15 patients with SMA and scoliosis treated with GRs for 54 ± 33 months. Radiographic measurements, complications, and hospital stay durations were compared with those of 80 GR patients with IIS/JIS observed for 43 ± 31 months. Measures of rib collapse, including T6:T10 mean rib-vertebral angle and T6:T12 thoracic width, were compared. Student t test was used to compare SMA and IIS/JIS values (significance level, P = 0.05).
Results: Primary radiographic measurements in patients with SMA improved from preoperative to latest follow-up as follows: curve, 89° ± 19° to 55° ± 17°; pelvic obliquity, 31° ± 14° to 11° ± 10°; space-available-for-lung ratio, 0.86 ± 0.15 to 0.94 ± 0.21; and T1-S1 length grew 8.7 ± 3.2 cm. Rib collapse continued despite GR treatment in SMA but not in IIS/JIS. Hospital stays were longer for SMA than for IIS/JIS for lengthening procedures (P = 0.01) and trended to be longer for initial surgery (P = 0.08) and final fusion (P = 0.06). Patients with SMA and IIS/JIS experienced, respectively, 0.5 and 1.1 major complications per patient (P = 0.02).
Conclusion: GRs improve trunk height and the space-available-for-lung ratio while controlling curve and pelvic obliquity in young patients with SMA with severe scoliosis, but they do not halt rib collapse. For patients with SMA, hospital stays were longer than those for patients with IIS/JIS, whereas the rate of major complications was lower.