Background: Skeletal abnormalities, including spinal deformities, in Noonan syndrome have been described, but no detailed and systematic study of such spinal deformities has been presented in the literature.
Methods: The cases of sixty patients with Noonan syndrome were reviewed retrospectively, and the general appearance, growth disturbance, and mental status of the patients were documented. Spinal deformities were evaluated radiographically, and the frequency, pattern, and severity of the curves were documented.
Results: Spinal deformity was present in eighteen (30%) of the sixty patients. Two patients had congenital spinal deformity. Of the remaining sixteen patients with scoliosis, nine had a single thoracic curve, four had a single thoracolumbar curve, and three had a double major curve. Thoracic lordosis was also present in three of these sixteen patients. No patient had only increased kyphosis or lordosis. The mean age when the spinal deformities were detected was nine years; seven deformities were detected before the age of seven years. Overall, surgery was recommended to eleven of the eighteen patients; it was recommended for the treatment of scoliosis (mean, 68.5 degrees; range, 45 degrees to 125 degrees ) in eight patients and for the treatment of an associated thoracic lordosis (8 degrees, 15 degrees, and 18 degrees ) in three. Seven of the eleven patients underwent spinal arthrodesis. The operation was deferred in one patient because malignant hyperthermia developed during the induction of anesthesia.
Conclusions: Scoliosis with an associated thoracic lordosis occurs more frequently in Noonan syndrome than has been reported previously. Since the deformities tend to develop early and are relatively severe, a clinical and, if necessary, radiographic assessment of the spine with careful follow-up should be performed for early detection and treatment of spinal deformity. Although malignant hyperthermia is rare, all patients with Noonan syndrome should be considered to be at risk for the development of this complication before operative treatment.