Long-term Follow-up of Pulmonary Function and Scoliosis in Patients With Duchenne's Muscular Dystrophy and Spinal Muscular Atrophy

Background: Spine surgery for neuromuscular scoliosis in patients with Duchene's Muscular Dystrophy (DMD) and Spinal Muscular Atrophy (SMA) remained controversial. This study aimed to review the long-term results of spine surgery and its effect on pulmonary function in these patients. Methods: A retrospective review was conducted for the above patients who had undergone surgery from 1990 to 2006 in a tertiary hospital. Their yearly lung function tests, clinical records, and x-ray films before and after surgery were reviewed. All patients had at least 2 lung function tests performed before surgery and at least 3 lung function tests performed after surgery. Records of perioperative pulmonary infections that resulted in hospital admissions were also retrieved from the hospital computer system. Results: Forty patients were reviewed: 29 with DMD, 11 with SMA. The mean follow-up period was 11.6 years. For patients with DMD, the mean correction of Cobb's angle from surgery was 34.1 degrees. The rate of decline of the predicted forced vital capacity preoperatively was 7.80% per year, and was reduced to 4.26% per year postoperatively (P < 0.001). For patients with SMA, the mean correction of Cobb's angle from surgery was 44.1 degrees. The rate of decline of the predicted forced vital capacity preoperatively was 5.31% per year, and was reduced to 1.77% per year postoperatively (P < 0.001). For both DMD and SMA patients, the difference between the rate of pre-operative and postoperative pulmonary infections that resulted in hospital admission were, however, not significant (P = 0.433 and 0.452, respectively). Conclusions: Scoliosis surgery in patients with DMD and SMA results in a long-term decreased rate of decline in pulmonary function over a follow-up period of more than 10 years. The level of the apical vertebrae of the scoliosis did not demonstrate a significant trend on the pulmonary function. The frequency of chest infections did not improve by scoliosis surgery.