The transtemporal supralabyrinthine (middle cranial fossa) approach offers surgeons the possibility to remove smaller vestibular schwannomas and preserve hearing.
Hearing loss, especially in one ear, is a common symptom with which patients with vestibular schwannoma present. There are however patients in which vestibular schwannomas are incidentally found on magnetic resonance imaging (MRI), performed for other reasons. In patients with normal hearing it is often advised to observe the tumour for fear of losing the hearing during intervention. It should be understood that in up to 15% of these patients sudden hearing loss may occur. It is also known that hearing can deteriorate even without any evidence on MRI that the vestibular schwannoma is growing.
The transtemporal supralabyrinthine approach was originally described by Professor Ugo Fisch of Switzerland. It can be utilized to remove small intracannalicular (in the internal auditory canal) tumours and preserve hearing. The smaller the tumour, the easier it is to perform a complete removal. Complications are also less likely and especially the facial nerve can be seen very well and monitored during this surgical procedure. Facial nerve injury is therefore avoided.
Vestibular schwannomas originate from the vestibular portion of the nerve and when small do not involve the cochlear (hearing) portion of the nerve. It can then be removed and the cochlear portion of the nerve preserved. Should some patients in rare cases sacrifice some hearing during this procedure they can benefit from amplification through a hearing device. In those extremely rare cases where unfortunate patients suffer total hearing loss due to damage to the blood supply a cochlear implantation(CI) is a possibility.
Observation of the vestibular schwannoma, in an attempt to prevent the deterioration in hearing for longer may actually result in the enlarging vestibular schwannoma destroying the cochlear fibers. In these patients no hearing device or even a CI will be of benefit. It is therefore important to discuss the effect of the vestibular schwannoma on hearing and the long term prognosis for hearing restoration. Hearing preservation is possible in vestibular schwannoma surgery.
A timely transtemporal supralabyrinthine removal of the vestibular schwannoma should be considered as an option for better long term hearing preservation.