Introduction: Surgery of the petroclival region is one of the most challenging aspects of skull base surgery. Some traditional approaches, including the translabyrinthine and transcochlear, sacrifice functional hearing. By combining surgical approaches to the middle and posterior cranial base with a conservative petrous bone dissection, radical resections can be achieved and hearing may be preserved. We describe the complex surgical anatomy involved in conservative, hearing preservation transpetrosal surgical techniques and assess advantages, surgical access, maneuverability, and indications for each one of these approaches.
Methods: Conservative transpetrosal bone resection centered on the labyrinthine block was performed on 10 cadaveric heads (20 sides). We considered four possible perilabyrinthine surgical corridors: pre-labyrinthine (middle fossa and anterior petrosectomy), epi-labyrinthine suprameatal, presigmoid retro-labyrinthine, and sub-labyrinthine corridors. Each surgical corridor was explored using both a microscope and 3D endoscope, and an assessment of surgical exposure was performed by multiple surgeons.
Results: The exposure achieved by each perilabirinthine surgical corridor was quantified. These corridors provided a surgical window to the upper half of the clivus (prelabirynthine corridor), postero-lateral petrous ridge, and tegmen tympani area (epilabyrinthine corridor) to the middle and lateral cerebello-pontine angle (presigmoid retrolabyrinthine corridor) and to the jugular foramen area (sublabyrinthine corridor). Use of these surgical corridors allowed for the minimization of brain stem and cerebellar retraction and for the sparing of functional hearing.
Conclusions: Surgical approach selection is dependent on the size, extension, type, and general location of the lesion, as well as the capability of the approach to better expose the target structures. The use of combined approaches may be indicated in some cases where hearing preservation and gross total resection are desired.
Patient Care: By providing alternative surgical approaches that would allow for the preservation of hearing that would otherwise be sacrificed.
Learning Objectives: By the conclusion of this session, participants should be able to understand the surgical anatomy involved in the preservation of hearing during surgical approaches to the petroclival region, cerebello-pontine angle, brainstem, and jugular foramen.