We determined the frequency, rate and extent
of development of scoliosis (coronal plane deformity) in wheelchair-dependent
patients with Duchenne muscular dystrophy (DMD) who were not receiving
steroid treatment. We also assessed kyphosis and lordosis (sagittal
plane deformity). The extent of scoliosis was assessed on sitting anteroposterior
(AP) spinal radiographs in 88 consecutive non-ambulatory patients
with DMD. Radiographs were studied from the time the patients became
wheelchair-dependent until the time of spinal fusion, or the latest assessment
if surgery was not undertaken. Progression was estimated using a
longitudinal mixed-model regression analysis to handle repeated
measurements. Scoliosis ≥ 10° occurred in 85 of 88 patients (97%), ≥ 20° in
78 of 88 (89%) and ≥ 30° in 66 of 88 patients (75%). The fitted
longitudinal model revealed that time in a wheelchair was a highly
significant predictor of the magnitude of the curve, independent
of the age of the patient (p <
0.001). Scoliosis developed in
virtually all DMD patients not receiving steroids once they became
wheelchair-dependent, and the degree of deformity deteriorated over
time. In general, scoliosis increased at a constant rate, beginning
at the time of wheelchair-dependency (p <
0.001). In some there
was no scoliosis for as long as three years after dependency, but
scoliosis then developed and increased at a constant rate. Some
patients showed a rapid increase in the rate of progression of the
curve after a few years – the clinical phenomenon of a rapidly collapsing
curve over a few months. A sagittal plane kyphotic deformity was seen in 37 of 60 patients
(62%) with appropriate radiographs, with 23 (38%) showing lumbar
lordosis (16 (27%) abnormal and seven (11%) normal). This study provides a baseline to assess the effects of steroids
and other forms of treatment on the natural history of scoliosis
in patients with DMD, and an approach to assessing spinal deformity
in the coronal and sagittal planes in wheelchair-dependent patients
with other neuromuscular disorders. Cite this article:
