Introduction: Arnold Chiari type 1 malformation (CM1) is a rare neurologic defect resulting in herniation of the cerebellar tonsils into the foramen magnum. Elevated intracranial pressure (ICP) has been associated with CM1 patients, potentially prohibiting neuraxial anesthesia. Reports of safely performed obstetric neuraxial anesthesia, including Combined-Spinal-Epidural (CSE), exist (1). Leffert et al. reviewed parturients with intracranial pathologies and provided a decision tree to assess feasibility of neuraxial anesthesia. Briefly, if there is no evidence of mass effect or obstructed CSF flow, intrathecal anesthesia is low risk for herniation (2). We report two primiparus patients with symptomatic CM1 who presented for primary Cesarean delivery (CD) where this decision tree was successfully applied.
Case one: 27 year-old primigravida at term presented to our high risk clinic with a history of MCTD, SLE, and bilateral avascular necrosis of the hips with mobility restrictions preventing vaginal delivery. She described symptomatic CM1, surgically decompressed three years prior, with progressive visual symptoms, positional headaches, and vomiting since decompression.
A pre-admission MRI of brain and spinal cord was obtained due progressive symptoms; it was negative for midline shift or hydrocephalus. After counseling the patient, a routine spinal anesthesia (SPA) was performed. CD was uneventful and she was discharged on POD2 with no new neurologic symptoms; she remained stable at her 6-week post-partum visit.
Case two: 30 year-old primigravida at term presented to our high risk clinic with obesity, status post gastric-bypass, OSA, chronic low-back pain, multiple psychiatric comorbidities, and symptomatic CM1 planned for decompression post-partum. Neurological symptoms included stable upper extremity radiculopathy, headaches, and ataxia since her last MRI. MRI showed significant 14cm herniation of peg-like tonsils and a small syrinx from C6 to T1. There was no evidence of hydrocephalus or midline shift. Neurosurgical consultation confirmed herniation risk to be minimal. The patient desired neuraxial anesthesia over GA for maternal-infant bonding.
Routine CSE anesthesia, due to surgical duration, was performed for her uneventful CD. She was discharged on POD2 with stable neurologic symptoms which were unchanged at her 6-week post-partum visit. Neurosurgical decompression is pending.
Conclusion: In conjunction with our high risk clinic, we used the decision tree suggested by Leffert et. al. (2) for risk assessment of neuraxial blockade in two complex, symptomatic CM1 parturients. Symptomology, MRI, and neurosurgical consultation were considered together to determine that both patients likely had normal ICP and were thus safe for intrathecal anesthesia. Both patients had uneventful CD with effective neuraxial anesthesia and the opportunity for early maternal-infant bonding.
1 Hopkins AN, Semin Perinatol. 2014
2, Leffert LR, Anesthesiology. 2013
