Spinal deformities in Noonan syndrome - A clinical review of sixty cases

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 ret rospectively, and the general appearance, growth disturbance, and mental st atus of the patients were documented. Spinal deformities were evaluated rad iographically, and the frequency, pattern, and severity of the curves were documented. Results: Spinal deformity was present in eighteen (30%) of the sixty patien ts. Two patients had congenital spinal deformity. Of the remaining sixteen patients with scoliosis, nine had a single thoracic curve, four had a singl e thoracolumbar curve, and three had a double major curve. Thoracic lordosi s was also present in three of these sixteen patients. No patient had only increased kyphosis or lordosis. The mean age when the spinal deformities we re 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 deg rees; range, 45 degrees to 125 degrees) in eight patients and for the treat ment of an associated thoracic lordosis (8 degrees, 15 degrees, and 18 degr ees) in three. Seven of the eleven patients underwent spinal arthrodesis. T he operation was deferred in one patient because malignant hyperthermia dev eloped during the induction of anesthesia. Conclusions: Scoliosis with an associated thoracic lordosis occurs more fre quently in Noonan syndrome than has been reported previously. Since the def ormities tend to develop early and are relatively severe, a clinical and, i f necessary, radiographic assessment of the spine with careful follow-up sh ould be performed for early detection and treatment of spinal deformity, Al though malignant hyperthermia is rare, all patients with Noonan syndrome sh ould be considered to be at risk for the development of this complication b efore operative treatment.