Spinal Deformity Correction in Duchenne Muscular Dystrophy (DMD): Comparing the Outcome of Two Instrumentation Techniques

Debnath, Ujjwal Kanti; Mehdian, Syed M Hossein; Webb, John K

Abstract

STUDY DESIGN: A retrospective matched cohort study. PURPOSE: To compare the results of combined Luque rod-sublaminar wiring (thoracic) and pedicle (lower lumbar) instrumentation (SLW) versus those with pedicle screw fixation (PS) for scoliosis correction in Duchenne muscular dystrophy (DMD). OVERVIEW OF LITERATURE: PS fixation is gaining popularity. Two instrumentation systems were not compared before in a matched cohort of patients.
METHODS
Two groups of patients with DMD were matched according to the age at surgery, magnitude of deformity and vital capacity. Indications for surgery included loss of sitting balance, rapid decline of vital capacity and curve progression. In group 1 (22 patients) SLW fixation was used from T2/3 to pelvis or sacrum. In group 2 (18 patients) PS fixation was used from T2/3 to L5. Five patients had all level segmental PS fixations. Minimum follow-up was 2 years (range, 2 to 13 years). Radiographs, lung function tests and subjective/objective assessment were performed at standardized intervals.
RESULTS
Mean Cobb angle in group 1 improved from 45.3degrees (range, 26 to 75degrees) to 17.7degrees(range, 0 to 37degrees) and mean pelvic obliquity improved from 14.5degrees (range, 8 to 28degrees) to 5.6degrees (range, 0 to 15degrees). Mean Cobb angle in group 2 improved from 42.8degrees (range, 28 to 80degrees) to 7.3degrees (range, 0 to 20degrees) and mean pelvic obliquity improved from 11.2degrees (range, 7 to 30degrees) to 2.0degrees (range, 0 to 5degrees) (p < 0.05). Mean operating time and blood loss were less in group 2 (p < 0.05). In group 1, the infection rate and instrumentation failure was higher, and subjective/objective outcomes showed no significant difference between the groups.
CONCLUSIONS
PS fixation had superior correction and controlled pelvic obliquity without the need for pelvic fixation.