Describe the preoperative evaluation of the patient with scoliosis.
A complete history and physical examination is a necessary part of the preoperative evaluation. Primarily, the pre-operative evaluation should focus on the cause and the implications of the scoliosis for anesthetic management. The evaluation should include the degree of spinal curva-ture, any cardiovascular impairment, and the presence of coexisting disease(s). Table 52.2 lists the studies that may be performed as part of the preoperative evaluation. Some or all of these studies will be ordered, depending on the severity of the scoliosis.
Pulmonary function tests play a major role in determining the anesthetic management of the patient for posterior spinal fusion surgery. Restrictive lung disease is the most common pulmonary abnormality observed with scoliosis. It is of particular note if the vital capacity is 30% or less of predicted, as this will often indicate the probable need for postoperative ventilation. If obstructive disease is present, it is important to know its response to bronchodilators.
Cardiovascular impairment is not uncommon in the patient with scoliosis. Mitral valve prolapse is the most common cardiovascular abnormality seen in these patients. Pulmonary dysfunction may cause changes in the pulmonary vasculature leading to pulmonary hypertension. The end result of pulmonary hypertension on the cardiovascular system is the development of right ventricular failure or cor pulmonale. Clinical findings of cor pulmonale include an S4 heart sound, jugular venous distention, hepatomegaly, pedal edema, and a left parasternal lift.
If a wake-up test is planned, then the procedure and what is expected of the patient must be explained and comprehended.
In the majority of patients, preoperative sedation is acceptable. However, it should be kept in mind that some patients with scoliosis will have a significant degree of respiratory dysfunction and preoperative sedation may be contraindicated. The resulting respiratory depression can cause hypoxemia, hypercarbia, and acidosis.