CPT® Code 61520

CPT® Code 61520 refers to a surgical procedure known as craniectomy for the excision of a brain tumor located in the infratentorial region or posterior fossa, specifically targeting tumors at the cerebellopontine angle. The cerebellopontine angle is a critical anatomical area situated at the junction of the cerebellum and the brainstem, filled with cerebrospinal fluid, and bordered medially by the brainstem, superiorly by the cerebellum, and laterally by the temporal bone. This region is significant as it is the most common site for intracranial posterior fossa tumors, with acoustic neuromas, also known as vestibular schwannomas, being the predominant type. These tumors arise from the acoustic nerve, which is positioned behind the ear and beneath the cerebellum, and are characterized by their slow growth. In addition to acoustic neuromas, other less common tumors may also occur in this area, including various benign tumors and both primary and metastatic malignant tumors. The surgical approach typically involves a retrosigmoid approach, which includes performing an occipital craniotomy to access the tumor. The procedure entails careful dissection and debulking of the tumor, including the removal of the posterior wall of the internal auditory canal to facilitate complete excision of the tumor. The meticulous nature of this surgery is crucial to avoid damage to surrounding structures, such as the brainstem and cranial nerves, particularly the facial nerve (cranial nerve VII). Following the successful removal of the tumor, the surgical site is meticulously repaired, including the closure of the dura and the reconstruction of the craniotomy site.