Prediction of progression of spinal deformity in Duchenne muscular dystrophy: a preliminary report.
METHODS
Discriminatory power was statistically estimated for multiple combinations of risk indicators for the progression of spinal deformity in Duchenne muscular dystrophy (DMD).


OBJECTIVE
To differentiate DMD cases in which spinal deformity will rapidly and severely progress from those with lesser progression of spinal deformity.


BACKGROUND
Early surgical intervention using instrumentation has recently been advocated for DMD patients to prevent the progression of spinal deformity. However, early determination of cases needing surgical intervention is difficult because of variations in the severity of the clinical courses of DMD patients.


METHODS
Charts and spinal radiographs of 12 DMD patients were reviewed retrospectively. Patterns of progression in spinal deformity were classified into three types according to Oda's classification. Discriminant analysis was conducted to categorize the patients into either a severe progression group (type-1 and type-2 patients) or a less severe progression group (type-3 patients and patients without spinal deformity) on the basis of four predictors: 1) vital capacity at the age of 10 years, 2) the age at which ambulation ceased, 3) curve pattern of spinal scoliosis, and 4) Cobb angles of spinal scoliosis at the age of 10 years.


RESULTS
Eleven of the twelve DMD patients showed spinal deformity. Three were classified as type 1, six were classified as type 2, and two were classified as type 3. The remaining patient showed no spinal deformity. Multiple discriminant analysis correctly predicted the severity of the clinical course of 91.7% of the DMD patients. Vital capacity at age 10 was found to be the strongest predictor among the variables.


CONCLUSIONS
Through multiple discriminant analysis, the clinical course of spinal deformity in DMD patients was correctly predicted in 92% of subjects. This method would be useful to determine early which DMD cases need surgical intervention for treatment of spinal deformity.
Yamashita
T
T
Department of Orthopaedic Surgery, Sapporo Medical University, Sapporo, Japan. tyamasit@sapmed.ac.jp
Kanaya
K
K
Kawaguchi
S
S
Murakami
T
T
Yokogushi
K
K
D002648:Child; D016002:Discriminant Analysis; D006801:Humans; D007738:Kyphosis / Q000209:etiology* / Q000503:physiopathology*; D008297:Male; D008962:Models, Theoretical; D020388:Muscular Dystrophy, Duchenne / Q000150:complications*; D011379:Prognosis; D012600:Scoliosis / Q000209:etiology* / Q000503:physiopathology*; D013997:Time Factors