Anesthesia for Syringomyelia

SYRINGOMYELIA

Syringomyelia results in progressive cavitation of the spinal cord. In many cases, obstruction of cerebrospinal fluid outflow from the fourth ven-tricle seems to be contributory. Many patients have craniovertebral abnormalities, particularly the Arnold–Chiari malformation. Increased pres-sure in the central canal of the spinal cord pro-duces enlargement or diverticulation to the point of cavitation. Syringomyelia typically affects the cervical spine, producing sensory and motor defi-cits in the upper extremities, and, frequently, tho-racic scoliosis. Extension upward into the medulla (syringobulbia) leads to cranial nerve deficits. Syringo-peritoneal shunting and other decompres-sive procedures have variable success in arresting the disease.

Anesthetic evaluation should focus on defin-ing existing neurologic deficits and any pulmonary impairment due to scoliosis. Autonomic instabil-ity should be expected in patients with extensive lesions. Succinylcholine should be avoided when muscle wasting is present because of the risk of hyperkalemia. Adequacy of ventilation and rever-sal of nondepolarizing NMBs should be achieved prior to extubation. Neuraxial techniques in the setting of elevated intracranial pressure are con-traindicated. Case reports of epidural anesthet-ics having been performed for labor analgesia in patients with Arnold Chiari malformations, with and without syringomyelia, can be found in the literature. Risks of cerebral herniation, worseningnerve injury, and infection must be weighed against potential benefits.