BACKGROUND: The Arnold-Chiari malformation type I is characterized by the prolapse of the cerebellar tonsils below the foramen magnum. There is a lack of literature on the management of a pregnancy in a woman affected by an Arnold-Chiari malformation.
CASE: A young primipara with severe headaches underwent an elective primary cesarean delivery under general anesthesia successfully. Five years earlier, she had undergone neurosurgical resection for filum terminale syndrome shortly after her first pregnancy (term vaginal delivery) and decompression of a type I Arnold-Chiari malformation 4 months later.
CONCLUSION: Careful selection of anesthetic technique for the delivery of a woman with an Arnold-Chiari malformation is of paramount importance.
The Arnold-Chiari malformation was first identified in 1883 by Cleland.1 It is characterized by the prolapse of hindbrain structures below the level of the foramen magnum. It can be associated with skeletal abnormalities and neurologic dysfunction. Chiari divided it into four classes. Type I, with displacement of cerebellar tonsils below the foramen magnum, is usually diagnosed in adults. Type II, with displacement of the cerebellar vermis, brainstem, and fourth ventricle through the foramen, is diagnosed in early childhood. In 95% percent of the cases it is accompanied by hydrocephalus and myelomeningocele. Type III, with a dilated fourth ventricle and cervical myelomeningocele, and type IV, with cerebellar hypoplasia, are very rare. All variants can be complicated with syringomyelia, or cystic degeneration within the spinal cord, and disruption of cervical vertebrae 1–3.2
Severe occipital headaches after exertion, coughing, or laughing are very characteristic.2 Other presenting symptoms are musculoskeletal pain, weakness and numbness of extremities, loss of temperature sensation, unsteadiness, nystagmus, and syncope.
There is a lack of literature on the management of a pregnancy in a woman affected by an Arnold-Chiari malformation. Moreover, information regarding the safety of allowing labor or the use of regional anesthesia in a woman with a corrected Arnold-Chiari malformation is limited. Suboccipital craniotomy and decompression has been of modest benefit in improving the symptoms caused by the craniospinal pressure dissociation associated with the disordered flow of the cerebrospinal fluid.2 Recently, Chantigian et al3 reported their institution's 50-year experience with women with this malformation and their pregnancy outcomes. In this series of 12 women, four women with a corrected malformation delivered vaginally, whereas one had a cesarean delivery. None of the five women developed symptoms or had an exacerbation of the symptoms associated with an Arnold-Chiari malformation.3
We report the case of a woman with an Arnold-Chiari malformation type I, diagnosed after her first pregnancy and corrected, who presented a dilemma for mode of delivery and type of anesthesia.