Following a cortical mastoidectomy, exposure and incision of the posterior cranial fossa dura behind the semicircular canals, thus revealing the cerebellopontine angle.

After the exposure of the posterior part of the sigmoid sinus; carrying out a limited craniotomy by drilling the retrosigmoid area, and exposure and incision of the posterior cranial fossa dura, thus revealing the cerebellopontine angle.

Carrying out a direct suboccipital craniotomy and incising the dura, thus revealing the cerebellopontine angle; followed by drilling away the posterior wall of the internal auditory canal.

Following a procedure similar to the transotic approach, uncovering the facial nerve, cutting the greater superficial petrosal nerve and transposing the facial nerve, i. e., labyrinthine, tympanic, and mastoid segments, posteriorly; thus allowing the exposure of all the medial structures, including the cerebellopontine angle.