Tos M

Gentofte University Hospital

DK-2900 Hellerup, Denmark

Translabyrinthine operation is the most commonly performed operation for acoustic neuroma surgery in our department, being in 75%, middle fossa in 20% and retrosigmoid surgery in 5% of cases.

Translabyrinthine surgery is the best operation for removal of giant and large tumor, simply because the surgeon can work around and within the tumor without any compression of the brainstem or cerebellum. The most important hint point in translabyrinthine surgery is to establish a wide exposure of the cerebellopontine angle, i.e. to remove all bone from the sigmoid sinus and behind it. Furthermore the bone from the entire middle fossa and posterior fossa dural plates as well as the sinodural angle has to be removed, making the entrance to the cerebellopontine angle soft and completely mobile, without any bony obstacles superiorly, posteriorly and inferiorly.

Labyrinthectomy is performed and the facial nerve skeletonized without exposing it. The jugular bulb is skeletonized, if prominent it is depressed by bone wax. In the meatal and porus regions all bone from the superior and inferior walls of the porus has to be drilled away, using diamond burrs, leaving no bone overhangs towards the anterior wall. Laterally the transversus crest is identified. Dura is opened superiorly along the superior petrosal sinus and inferiorly along the sigmoid sinus. Laterally in the meatus the facial nerve is identified by several ways: a) by identification of the Bill's bar; b) inferior dissection along the acoustic nerve or c) medial identification of the facial nerve. The small tumor is elevated from the facial nerve and removed in toto. Large tumors are dissected and its surface debulked and removed piece by piece.