A Case of Petrous Apex Cholesteatoma Removed Using an Exoscope and an Endoscope Without Posterior Rerouting of the Facial Nerve.

Petrous apex cholesteatoma (PAC) is a rare disease extending into the deep area of the temporal bone. Traditionally, lesions surrounding the geniculate ganglion often required facial nerve rerouting, which carries the inherent risk of worsening facial nerve function due to neural ischemia. We report a case of PAC successfully removed via subtotal petrosectomy combined with a trans-superior semicircular canal approach, achieving complete resection while preserving neural function. A 43-year-old female with a history of surgery for cholesteatoma and pre-existing left-sided deafness presented with left moderate facial nerve palsy and vertigo. CT revealed a PAC extending from the epitympanum to the middle cranial fossa and the superior internal auditory canal. We performed a subtotal petrosectomy combined with a trans-superior semicircular canal approach. The surgery was conducted under exoscopic visualization for safe bone drilling; however, for the deepest lesions located medial to the geniculate ganglion and the labyrinthine segment, which typically require posterior facial nerve rerouting, a 30-degree angled endoscope was utilized. This hybrid approach allowed for complete resection without the need for rerouting. Postoperatively, there was no worsening of facial palsy or vestibular dysfunction. Six months later, there was no evidence of recurrence. For PAC extending deep into the temporal bone, the strategic combination of an exoscope and an angled endoscope enables safe, minimally invasive total resection while avoiding facial nerve rerouting. This approach represents a valuable surgical option that allows complete resection and neural preservation.