CPT® Code 61345

A posterior fossa cranial decompression is a surgical procedure primarily performed to alleviate symptoms associated with Arnold-Chiari malformation, particularly in cases where there is tonsillar herniation. This condition can lead to various neurological symptoms, including severe headaches, hydrocephalus (accumulation of cerebrospinal fluid in the brain), and syringomyelia (the formation of a cyst within the spinal cord). The posterior fossa is a small space located at the lower back of the skull, which houses critical structures such as the cerebellum and brainstem. In a healthy individual, the cerebellar tonsils, which are small protrusions at the bottom of the cerebellum, remain entirely within the confines of the skull. However, in individuals with Arnold-Chiari malformation, these tonsils can herniate through the foramen magnum, the opening at the base of the skull, into the spinal canal, leading to increased intracranial pressure and disruption of normal cerebrospinal fluid (CSF) flow. The goal of posterior fossa decompression is to relieve this pressure by removing a portion of the skull, thereby creating additional space for the herniated cerebellum and restoring normal CSF circulation. This procedure is critical for preventing further neurological deterioration and improving the patient's quality of life.