Endoscopically-assisted transmastoid approach to the geniculate ganglion and labyrinthine facial nerve

Abstract

BackgroundEndoscopic transcanal approaches to the facial nerve allow excellent exposure of the tympanic facial nerve. This approach becomes limited when access is required to the more proximal geniculate ganglion and labyrinthine portion of the facial nerve. The aim of this report was to determine the feasibility of a transmastoid endoscopically assisted approach to the geniculate ganglion and labyrinthine facial nerve. This is an endoscopic cadaveric dissection and video review at a university anatomical laboratory.MethodsA total of 12 endoscopic cadaveric dissections were performed. A cortical mastoidectomy and perilabyrinthine air cell removal was performed using an operating microscope. Beyond this, dissection was performed with an endoscope.ResultsIn all dissections, an endoscopically assisted transmastoid approach allowed complete access to the geniculate ganglion, and at least 1.5 mm of the distal labyrinthine facial nerve. Further transcrusal drilling through the anterior crus of the superior semicircular canal allowed access to the entire labyrinthine facial nerve.ConclusionsThe entire geniculate ganglion and labyrinthine facial nerve is difficult to access with microscopic techniques. Adding endoscopic visualization allows for complete visualization of the geniculate ganglion. Clinical reports will further strengthen these preliminary cadaveric results.

Suprameatal–transzygomatic root endoscopic approach to the geniculate ganglion: an anatomical and radiological study

“…Recently some authors described the radiologic criteria (petrous bone CT scan) which permit preoperatively to predict the feasibility of this type of approaches 7 . Other authors suggested to improve the limited visualization of the trans-mastoid approach with endoscopic assistance in a cadaveric study 18 . To gain adequate surgical exposure through this approach several reports suggest to uncover the middle cranial fossa dura through the TMA, to permit temporal lobe retraction, gaining a better exposure of the geniculate ganglion area [8][9][10] .…”

Endoscope-assisted facial nerve decompression for traumatic tympanic segment of facial nerve paresis

“…7 Another study mentioned the role of endoscope-assisted transmastoid approach facial nerve decompression involving the second genu and the labyrinthine segment of the facial nerve. 8 With regard to our case, the conventional transmastoid approach was initially performed. However, the lesion at the distal portion of the tympanic segment of the facial nerve was obstructed by the dome of the lateral semicircular canal with the surgical microscope.…”

Burr Hole Endoscopic Mastoidectomy: A Morphometric Cadaveric Study

“…Various studies have promoted the transcanal endoscopic "inside-out" technique, 10-14 endoscopic assisted intramastoid dissection, 15 and robotic-guided approaches. [16][17][18] However, no study has yet focused on a minimally invasive burr hole endoscopic approach through a small postauricular incision.…”