Presigmoid Retrolabyrinthine Approach Research Articles

Microsurgical endoscopy-assisted presigmoid retrolabyrinthine approach as a minimally invasive surgical option for the treatment of medium to large vestibular schwannoma

The paper from Iacoangeli and his colleagues from Ancona and Rome in this issue of Acta Neurochirurgica is timely given the continuing controversy on best treatment options for vestibular schwannomas. Their report is on the preliminary experience with an old approach integrated with the endoscope. The case material includes ten cases of small and medium sized sporadic acoustic neuromas (five cases of 8 and 10 mm, five cases of 11–25 mm), selected on the basis of a favourable anatomy of the temporal bone. It is noteworthy, and rather exceptional in comparison to other’s experiences, that only three cases out of ten had a preoperative normal facial nerve function, while four cases of 11–25 mm had a House-Brackmann (HB) grade 3 and three cases of 10 and 20 mm had a HB grade 2, which makes 70 % of preoperative facial dysfunction in small and medium-size tumors. The surgical outcome was outstanding, with unchanged postoperative facial function (with the exception of the case with preoperative radiotherapy), only one case experiencing a hearing loss from AAORLHNS class B to C, and no instances of deafness. The removal of tumors from the internal auditory canal without a drill meatotomy in this series might have been favoured by a limited extension into the canal. The results on the hearing and facial nerve are superior to the results reported in the literature.

Surgical Obliteration in Superior Petrosal Sinus Dural Arteriovenous Fistula

Superior petrosal sinus (SPS) dural arteriovenous fistula (DAVF) is one of tentorial DAVFs with significant morbidity, which usually drains into the petrosal vein and its tributaries. Unless there is a connection with venous sinus, surgical obliteration is required. We present two cases of SPS DAVF which were successfully treated with the presigmoid retrolabyrinthine approach.

Commentary

The presigmoid retrolabyrinthine approach is very useful for small lesions involving the cerebellopontine angle and vestibulocochlear nerve complex and for vestibular neurectomy. It also can be combined with a supratentorial craniotomy to access lesions of the petroclival region that may extend above or below the tentorium. The benefit of the retrolabyrinthine approach is that the surgeon primarily works in the presigmoid region. Consequently, the posterior extent of the craniotomy and possibly some of the soft tissue dissection can be limited. The disadvantage is that access to the medial cerebellopontine angle is limited. An extension of this approach, the partial labyrinthectomy, has been reported to be associated with good preservation of hearing while improving access to the cerebellopontine angle. Although we have not attempted this technique at our institution, we are interested in the experience of other centers. Overall, this excellent article reminds both neurosurgeons and neuro-otologists of the versatility and usefulness of this approach.