Scoliosis is lateral rotation and curvature of the ver-tebrae and a
deformity of the rib cage. It can have many etiologies, including idiopathic,
congenital, neuromuscular, and traumatic. Scoliosis can affect cardiac and
respiratory function. Elevated pul-monary vascular resistance from chronic
hypoxia causes pulmonary hypertension and right ventricu-lar hypertrophy.
Respiratory abnormalities include reduced lung volumes and chest wall
compliance. Pao2 is reduced as a result of ventilation/perfusion mismatching, whereas an
increased Paco2 signals severe disease.
Preoperative evaluation may include pulmonary
function tests, arterial blood gases, and electrocar-diography. Corrective
surgery is complicated by the prone position, significant blood loss, and the
possibility of paraplegia. Spinal cord function can be assessed by neurophysiological
monitoring (somatosensory and motor evoked potentials) or by awakening the
patient intraoperatively to test lower limb muscle strength. Patients with
severe respiratory disease often remain intubated postoperatively. Patients
with scoliosis due to muscular dystrophy arepredisposed to malignant
hyperthermia, cardiac arrhythmias, and untoward effects of succinylcho-line
(hyperkalemia, myoglobinuria, and sustained muscular contractures).