Skull Base Surgery: Approach Selection and Complications
Core concepts
Skull base questions require matching tumor location and pathology to surgical corridor. Know the middle fossa, translabyrinthine, retrosigmoid, and transcochlear approaches to the cerebellopontine angle, and when hearing preservation is feasible. Understand the anterior skull base endoscopic endonasal corridor for pituitary and sinonasal lesions. Recognize the anatomy at risk: facial nerve in the internal auditory canal, sigmoid sinus, jugular bulb, internal carotid artery, and lower cranial nerves. Know that the translabyrinthine approach sacrifices hearing but gives early facial nerve identification; retrosigmoid allows hearing preservation but poorer facial nerve exposure.
Traps in questions
- Translabyrinthine is chosen for non-serviceable hearing, not for hearing preservation.
- The middle fossa approach is for small intracanalicular tumors with serviceable hearing.
- CSF leak is the most common complication after skull base surgery; recognize and manage with lumbar drain or repair.
- Venous sinus thrombosis and lower cranial nerve deficits follow jugular foramen surgery.
- Do not conflate approach with pathology; the question may ask which approach best preserves a specific function.
Worked rule of thumb
For a small intracanalicular vestibular schwannoma with good hearing, choose middle fossa. For a large tumor with non-serviceable hearing, choose translabyrinthine. For a tumor with brainstem compression, retrosigmoid offers access with hearing preservation potential.