Early presentation of spinal stenosis in achondroplasia.

One third of patients with achondroplasia develop spinal stenosis requiring surgical intervention. However, this condition rarely develops before the age of 15 years. The goal of the current study was to identify anatomical factors and clinical symptoms associated with early presentation of lumbar stenosis in such patients. The charts of 22 pediatric patients with achondroplasia who developed lumbar spinal stenosis requiring surgery (subjects) were reviewed retrospectively, focusing on clinical presentation, physical examination findings, and radiographic data. These findings were compared with those of a group of patients who had not developed stenotic symptoms (controls). Analysis was performed using chi2 test. Significance was set at P < 0.05. All 22 subjects presented with neurogenic claudication (weakness, pain, and/or numbness), and 77% had bladder incontinence. Compared radiographically with controls, the subjects had a significantly larger average percentage decrease in the transverse interpedicular distance from T12 to L5 (-8% vs -19%, respectively) and a significantly greater thoracolumbar kyphosis angle (24.2-degree angle vs 14.1-degree angle, respectively). These features were associated with an increased likelihood of developing symptomatic stenosis. The study indicated that 6 patients (32%) of the control group had caudal widening of the lumbar spine from T12 to L5.