Lumbar vs Sacral Fixation in the Surgical Management of Scoliosis is Duchenne Muscular Dystrophy

Centre for Spinal Studies and Surgery
Queen's Medical Centre, University Hospital Nottingham, Nottingham, UK and
*Robert Jones and Agnes Hunt
Orthopaedic Hospital, Oswestry, UK

PURPOSE:
This retrospective study evaluates whether fixation down to sacrum is always indicated, in the surgical treatment of scoliosis in Duchenne muscular dystrophy (DMD).

METHOD:
50 cases of DMD, operated in two different centres, and followed-up for a minimum of three years, were reviewed. In the first group (Oswestry), 31 patients had fixation down to the pelvis, using standard Luque instrumentation and pelvic fixation. The Galveston technique was used in 9 cases and L-rod configuration in 22 cases. In the second group (Nottingham), 19 patients had fixation down to the L-5 vertebra using pedicular screws in the lumbar spine and sublaminar wires in the thoracic spine. These cases were operated early, shortly after becoming wheelchair dependent.

RESULTS:
In the pelvic fixation group, the mean age at the time of surgery was 14 years and forced vital capacity (FVC) was 44%. The mean Cobb angle and pelvic obliquity were 48° and 19.8° respectively. Immediately after surgery the Cobb angle and pelvic obliquity measured 16.7° and 7.2° and at final follow-up (mean 4.6 years) was 22º and 11.6º. The mean blood loss was 4.1 litre and the average hospital stay was 17 days. There were four complications including a deep wound infection in one case, trimming of the rod in two cases and reinsertion of the rod in one case. In the lumbar fixation group, the mean age at the time of surgery was 11.7 years, and FVC was 58%. The mean Cobb angle and pelvic obliquity were 19.8° and 9° respectively at the time of surgery. Immediately after surgery the Cobb angle and pelvic obliquity were 3.2° and 2.2° and at final follow-up (mean 3.5 years) these were 5.2° and 2.9° respectively. The mean estimated blood loss (3.3 litre) and average hospital stay (7.7 days) were significantly less (p<0.05) compared to the pelvic fixation group. One patient had loosening of instrumentation and one other had a deep wound infection. Pelvic obliquity was corrected and maintained below 10° in all but two cases who had an initial pelvic obliquity exceeding 20°.

CONCLUSIONS:
Pelvic fixation may be necessary in presence of larger curve and significant pelvic obliquity, in older children. In presence of deteriorating lung function this is associated with greater morbidity and higher complication rate. Lumbar fixation to L-5 is adequate if the surgery is performed early, soon after being wheel chair bound, due to the smaller curves and minimal pelvic obliquity. Use of pedicle screws in lumbar spine provides a solid foundation to maintain the correction over the period of short life expectancy of these children.