Chiari I Malformation in Pregnancy: A Retrospective Review of Maternal Outcomes and Anesthetic Safety, and a Survey of Current Practices

Abstract

We sought to evaluate outcomes of pregnant patients with Chiari malformation (CM). We evaluated the relationships between mode of anesthesia and delivery with neurologic outcome in these patients.

We conducted a single-center, retrospective review of pregnant patients with CM between 2008 and 2024. Clinical and radiographic data were collected. Additionally, three neurosurgeons retrospectively determined eligibility for vaginal delivery with the Valsalva maneuver and neuraxial anesthesia with the available information.

We identified 56 deliveries in 40 patients with Type I CM. Median tonsillar descent was 8 mm (interquartile range [IQR] 4.5–11.5). Seven deliveries (16.7%; six patients) featured patients with syrinxes (median diameter 4.5 mm, IQR 4.0–4.5 mm). During pregnancy, 11 patients (19.6%) had symptoms attributable to CM, most commonly headache (5 patients, 8.9%). Two (40%) patients with Chiari-related headaches experienced worsening symptoms during pregnancy. Twenty-two pregnancies resulted in vaginal deliveries (39.3%), and 34 in cesarean deliveries (60.7%). Eleven cesarean deliveries (32.3%; 19.6% of whole cohort) had primary indication of CM for operative delivery. Neuraxial anesthesia was used in 29 patients (52%), 17 of whom were for cesarean deliveries (50% of cesareans). During labor, there were no maternal mortalities or worsening CM-related symptoms. On blinded retrospective assessment, one neurosurgeon found 51/56 deliveries (91.1%) safe for vaginal delivery and all safe for neuraxial anesthesia; one neurosurgeon found all deliveries safe for vaginal delivery and neuraxial anesthesia; the last one found 54/56 deliveries (96.4%) safe for vaginal delivery and 55/56 (98.2%) safe for neuraxial anesthesia. Concerns arose from brainstem compression and foramen magnum crowding with symptomatic worsening during pregnancy.

A diagnosis of Type I CM imparts higher rates of cesarean delivery (61%) and lower rates of neuraxial anesthesia to pregnant persons. Yet, our outcomes suggest that vaginal delivery with the Valsalva maneuver and neuraxial anesthesia appear to be safe in almost all pregnant patients with CM.