Epidural Anesthesia for Cesarean Section for Parturient with Recently Diagnosed Asymptomatic Chiari Malformation Type I: A Case Report.

Description Chiari malformations (CMs) are congenital defects of the brain and skull that result in inferior displacement of the cerebellum. There are four types of CMs distinguished by the severity of the anatomic defects and parts of the brain that protrude beyond the foramen magnum. Of these types, CM Type I (CMI) is the least severe. It is characterized by the downward displacement of the cerebellar tonsils beyond the foramen magnum by more than 5 millimeters and goes into the cervical spinal canal. CMI is the most common type with an incidence of 0.1-0.5% in the general population and a predominance in females. Given its relatively benign nature, CMI is often found incidentally or in adulthood when symptoms such as a headache or neck pain are present. It can be associated with syringomyelia or, less commonly, hydrocephalus. Although surgical decompression can be performed, most patients do not require surgical treatment. CMs present a unique challenge for anesthesiologists providing care to parturients. Since a majority of patients do not have a history of surgical decompression or ventriculoperitoneal shunting, it is difficult to evaluate for hydrocephalus when the patient is in labor. Therefore, many patients with diagnosed CMI are scheduled for an elective cesarean section. Numerous case reports and literature reviews have documented the successful use of spinals, epidurals and combined spinal-epidurals (CSEs) in these patients without neurologic sequelae. The patient in this case presented with CMI, which was diagnosed one year prior to our encounter, without any treatment. At the time of labor, she was asymptomatic. Although she had two prior vaginal deliveries under epidural anesthesia, she was scheduled for an elective cesarean section this time given the new diagnosis. This case report demonstrates the safe and successful use of epidural anesthesia for a parturient with CMI.