Parturients with Chiari Malformation Type 1 - A Case for Management Based on Symptoms
Abstract Number: T-27
Abstract Type: Case Report/Case Series
Despite decades of experience, anesthetic management for patients with Chiari Malformation (CM) remains a topic of debate. With an incidence of 0.5%, a female: male ratio of 3:1 and typical presentation in the 2nd-4th decades of life, most obstetric anesthesia providers will manage this condition during their career. Of the four distinct types of CM, type 1 is the most common, and is characterized by protrusion of the cerebellar tonsils through the foramen magnum. Clinical symptoms include headaches, neck pain, and rarely, upper limb numbness or weakness. Although imaging is diagnostic, the degree of tonsillar descent does not correlate directly with symptoms.
Acquired CM as a result of lumbar CSF drainage is well documented. (1) Despite concern that neuraxial anesthesia could worsen herniation due to CSF loss, safe provision of neuraxial anesthesia in CM patients is also well documented. (2,3) The question remains, however, whether clinical markers can be useful in making the decision to provide neuraxial anesthesia. After review of the literature and the recent obstetric management of eight patients, we propose that the presence of clinical symptoms may be helpful in counseling patients concerning the potential risks associated with neuraxial techniques for patients with CM.
We present eight obstetric patients with underlying CM type 1 diagnosed by MRI. Delivery course was dictated by obstetric indications. The degree of tonsillar herniation ranged from 3 – 12 mm; all had headaches, and three had neurologic symptoms of upper limb deficits, and vision and hearing changes. Of all patients, one received spinal anesthesia for cesarean section and four had labor epidural analgesia. Three of these four patients failed induction and underwent cesarean section with epidural anesthesia. There were no anesthetic complications or post-partum progression of neurologic symptoms. The three patients with neurologic symptoms received non-neuraxial anesthetic techniques. Two underwent general anesthesia for cesarean section and one received IV opioids for labor analgesia. None of these patients had post-partum symptom progression.
Given the potential risk of worsening hind brain herniation associated with CSF loss, and the inherent risk of dural puncture with a neuraxial technique, it appears prudent to counsel patients with CM about the risks and choose the anesthetic technique that appears safest based on their clinical symptoms. In our series, three women were provided alternative analgesia for labor and delivery due to concern that underlying upper limb numbness and weakness, or visual and hearing loss, potentially could be worsened with dural puncture.
1. Neurosurg. 34(3), 1994, 429-34.
2. Am J Perinat. 22(2), 2005, 67-70.
3. Case Rep Anes. 2013. http://dx.doi.org/10.1155/2013/512915