Spinal Muscular Atrophy

Abstract

Spinal muscular atrophy (SMA) is an autosomal recessive (principal form), progressive, neuromuscular disease, caused by a defect in the survival motor neuron 1 gene. The physiologic changes of pregnancy are poorly tolerated in SMA patients who frequently experience increasing muscle weakness and progressive respiratory insufficiency throughout pregnancy. Because of respiratory insufficiency, challenging airway anatomy, and spinal deformities, formulating an adequate anesthetic plan is difficult. Although there are typically no contraindications to placing an epidural for labor analgesia, patients with SMA have an increased incidence of difficult epidural placement and inadequate blockade. For cesarean delivery, neuraxial anesthesia is typically preferred although this will ultimately depend on the degree of respiratory insufficiency. Due to various degrees of severity, no single anesthetic plan will be best for all pregnant women with SMA, and a tailored approach should be developed, which optimizes the opportunity for a successful delivery and minimizes risk.