Background: The prevalence of scoliosis in patients with myelomeningocele has been reported to be as high as 80% to 90% in some studies. However, those studies included patients with both congenital and developmental curves. The variation in the patient population as well as the definition of scoliosis in those studies made it difficult to predict the true prevalence of scoliosis in these patients. The purpose of the present study was to identify clinical and radiographic factors that may predict the onset of developmental scoliosis in patients with myelomeningocele.

Methods: A retrospective review of the charts and radiographs of all patients with a diagnosis of myelomeningocele who were seen in our clinic between 1990 and 1995 was performed. The criteria for inclusion in the study included a diagnosis of myelomeningocele or lipomeningocele, an age of more than ten years at the time of the review, serial documentation of motor power, and radiographic documentation of spinal deformity primarily in the coronal plane. The radiographs were examined to assess the degree of scoliosis and to document the last intact laminar arch. The relationship between the degree of scoliosis and the last intact laminar arch was evaluated. Statistical analysis was performed to assess the association between scoliosis and the clinical motor level, the ambulatory status, spasticity, motor asymmetry, and hip instability.

Results: One hundred and forty-one patients satisfied the criteria for inclusion in the study. Seventy-four patients (52%) had scoliosis. The average duration of follow-up was 9.4 years (range, three to thirty years), and the average age of the patients was nineteen years (range, ten to forty-two years). Scoliosis developed before the age of nine years in forty-three patients and after the age of nine years in thirty-one patients, with new curves continuing to develop until the age of fifteen years. Curves of <20° degrees often resolved. The clinical motor level, ambulatory status, and last intact laminar arch were all found to be predictive factors for the development of scoliosis in these patients.

Conclusions: In the population of patients with myelomeningocele, the term scoliosis should be reserved for curves of >20°. New curves may continue to develop until the age of fifteen years. The level of the last intact laminar arch is a useful early predictor of the development of scoliosis in these patients.