2025 Poster Presentations
P106: A DETAILED ANATOMICAL STUDY FOR POSTERIOR PETROSECTOMY BY EXPOSING THE ROUND AND OVAL WINDOWS
Renan Lovato; Feng Cai; Mohamad Karam Bounah; Abdullah Keles; Ufuk Erginoglu; Mustafa Baskaya; University of Wisconsin Madison
Objectives: Study objectives are to demonstrate a step-by-step approach to posterior petrosectomy, including drilling the petrous bone between the facial nerve (CN VII) and the chorda tympani, to expose the round and oval windows.
Background: Posterior petrosectomy serves as a crucial technique for skull base surgery but presents challenges due to anatomical intricacy. Exposure of the oval and round windows aids identification of the promontory and the cochlea, vital landmarks in the middle ear. This approach is beneficial for addressing tumors invading the middle ear and for facilitating cochlear implantation during the same procedure.
Methods: Four posterior petrosectomies were performed on cadaveric specimens at the University of Wisconsin-Madison Microneurosurgery Laboratory. A C-shaped retroauricular incision was made, followed by the exposure of bony landmarks for the posterior petrosectomy. Subsequent drilling of the petrous bone enabled identification of the semicircular canals, jugular bulb, Trautmann’s triangle, the atrium with the incus bone, the facial nerve, and the chorda tympani. The next step involved drilling the bone between the chorda tympani and facial nerve, thus exposing the tympanic cavity and identifying the ossicles, round and oval windows, and the cochlear promontory.
Results: Drilling the temporal bone between the chorda tympani and the facial nerve, with or without labyrinth removal, broadens the surgical approach and facilitates identification of the round and oval windows, as well as the promontory. This technique proves advantageous for lesions extending into the middle ear and for patients requiring cochlear implantation in the same surgery.
Conclusions: Posterior petrosectomy is a complex yet significant approach for skull base surgeons. Opening the bone between the chorda tympani and the facial nerve offers access to the middle ear, which can provide substantial value for treating lesions in this area and for performing cochlear implant surgeries.
Opening the bone between the chorda tympani and the facial nerve offers access to the middle ear, proving to be invaluable for treating lesions in this area and for performing cochlear implant surgeries.