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°; range, 45° to 125°) in eight patients and
for the treatment of an associated thoracic lordosis (8°, 15°, and
18°) 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.