CPT® Code 61598

Transpetrosal approach to posterior cranial fossa, clivus or foramen magnum, including ligation of superior petrosal sinus and/or sigmoid sinus

The transpetrosal approach to the posterior cranial fossa, clivus, or foramen magnum is a surgical technique utilized primarily for accessing and treating conditions such as neoplastic tumors and vascular lesions located in these critical areas of the brain. This approach is characterized by its strategic incision and manipulation of surrounding anatomical structures to provide the surgeon with optimal visibility and access to the targeted region. The procedure begins with the immobilization of the patient's head, followed by a precise skin incision that initiates approximately 1 cm anterior to the tragus of the ear. The incision extends along the superior temporal line, curving posteriorly and caudally to reach about 6 cm behind the external auditory canal, ultimately terminating at the mastoid tip. Once the skin flap is elevated, the underlying temporalis muscle, pericranium, and suboccipital muscles are carefully retracted to expose the cranial bone. A flap may be harvested from the pericranium or temporalis fascia, which can be utilized later for dural closure. The surgical team then performs a temporo-suboccipital craniotomy, which involves creating multiple burr holes in the skull. These burr holes are interconnected using a drill or craniotome, allowing the bone flap to be lifted and providing access to the posterior fossa dura and the transverse sinus. To enhance visualization during the procedure, the squamous temporal bone may be flattened to align with the middle fossa floor. The middle fossa dura is elevated towards the petrous ridge, with careful attention to preserving vital blood vessels and nerves. The surgical dissection continues posteriorly toward the arcuate eminence, with the sigmoid sinus and presigmoid dura being alternately elevated off the mastoid bone. Bone resection is performed using cutting burrs and rongeurs, allowing for the identification of the posterior semicircular canal. The cortical bone is meticulously skeletonized while preserving the facial nerve, followed by the identification and skeletonization of the superior semicircular canal (SSC). The procedure culminates with the resection of the petrous ridge at the petrous apex, extending from the SSC to the trigeminal nerve. The posterior fossa is then opened along the anterior border of the sigmoid sinus, with the opening extended caudally to the superior petrosal sinus. Finally, the dura is opened through the trigeminal dural ring, retracted, and secured with stay sutures, providing a clear view of the petroclival region of the brain for further surgical intervention.