Chiari Type II Malformation: Timing for the Treatment and Surgical Technique

Introduction Chiari malformations (CMs) are structural defects in the cerebellum and posterior cranial fossa. Chiari type II malformation is almost invariably associated with myelomeningocele. Because of its greater severity, it becomes symptomatic in infancy or early childhood. Its hallmark is caudal displacement of lower brainstem (medulla, pons, fouth ventricle) through the foramen magnum. Symptoms arise from dysfunction of brainstem and lower cranial nerves.

Material and Methods In this paper, we present timing and technique of surgery. Almost all of patients presented with swallowing difficulty, stridor, apneic spells, aspiration, weakness of cry, and arm weakness. Posterior fossa decompression in the Chiari II malformation was performed in all patients. The mean follow-up period in this group of patients was 5 years. Early recognition of the symptoms of Chiari II malformation should be followed by decompression to promote a prompt and full neurological recovery.

Results A posterior fossa decompression is a surgical procedure performed to remove the bone at the back of the skull and spine. The dura overlying the tonsils is opened and a patch is sewn to expand the space. The goals of surgery are to stop or control the progression of symptoms caused by tonsillar herniation, to relieve compression of the brainstem and spinal cord, and to restore the normal flow of cerebrospinal fluid (CSF). The surgery takes ∼2 to 3 hours and recovery in the hospital usually lasts 2 to 4 days.

Conclusion Chiari II malformation is progressive with worsening of symptoms and possibly lethal. Patients should be carefully observed. Early recognition of the symptoms of Chiari II malformation should be followed by decompression to promote a prompt and full neurological recovery.

Keywords Chiari II malformation; posterior fossa decompression; tonsillar resection