Background: Congenital anomalies of the ribs and chest wall as well
as Sprengel deformity of the shoulder are often associated with congenital
deformities of the spine. It has been suggested that rib anomalies may
adversely affect the progression of the spinal deformity.
Methods: We conducted a retrospective study of the medical records
and spine radiographs of 620 consecutive patients with congenital deformities
of the spine; 497 patients (80%) had scoliosis; eighty-eight patients (14%),
kyphoscoliosis; and thirty-five patients (6%), kyphosis. The rib anomalies
were classified into simple and complex, and the presence of a Sprengel
deformity of the shoulder was recorded. The rate of scoliosis deterioration
without treatment before the age of eleven years, as well as the patient age
and curve size at the time of surgery, was compared for different types of
vertebral abnormalities in patients with and without rib anomalies.
Results: A total of 119 patients (19.2%) had rib anomalies, which
were most commonly associated with congenital scoliosis (111 patients; 93%)
and were much less frequently associated with congenital kyphoscoliosis or
kyphosis (eight patients). The rib anomalies were simple in ninety-five
patients and complex in twenty-four. Eighty-five patients (71%) with rib
abnormalities had a scoliosis due to a unilateral failure of vertebral
segmentation, and seven patients had mixed or unclassifiable vertebral
anomalies. In contrast, only sixteen of 203 patients with a scoliosis due to a
hemivertebra alone had rib anomalies. The rib anomalies were most frequently
associated with a thoracic or thoracolumbar scoliosis (102 patients; 92%) and
occurred on the concavity in eighty-two patients (74%), the convexity in
twenty-two patients (20%), and were bilateral in seven patients. The Sprengel
deformity occurred in forty-five patients and most frequently in association
with a thoracic scoliosis due to a unilateral failure of vertebral
segmentation (twenty-seven patients). No significant difference was detected
in the rate of curve progression without treatment in patients with and
without rib anomalies. The only exception was the mean age at the time of
surgery, which was higher for patients with a unilateral unsegmented bar
without rib anomalies (p = 0.005). In addition, no significant difference was
found with regard to any tethering effect due to the site of the rib fusions
on the concavity of the scoliosis, i.e., whether they were in close
approximation to the spine or were more lateral (p > 0.05).
Conclusions: Congenital rib anomalies occur most commonly on the
concavity of a thoracic or thoracolumbar congenital scoliosis that is due to a
unilateral failure of vertebral segmentation, and they do not appear to have
an adverse effect on curve size or rate of progression.
Level of Evidence: Prognostic Level II. See Instructions
to Authors for a complete description of levels of evidence.