At a glance
- Described by
- William House (1964)
- Hearing
- Sacrificed
- Facial nerve
- Identified at the fundus (Bill's bar)
- Best for
- Large VS or non-serviceable hearing
- Closure
- Abdominal fat graft
Overview and history
William House described transtemporal microsurgical removal of acoustic neuromas in 1964, using the operating microscope and the labyrinthine route[1]. The approach removes the mastoid and the semicircular canals to expose the internal auditory canal along its full length and the CPA from a lateral direction, without retracting the cerebellum. It allows reliable identification of the facial nerve at the fundus, where its position is constant regardless of tumour size.
Indications
- Vestibular schwannomas of any size when hearing is non-serviceable.
- Large vestibular schwannomas where hearing preservation is unlikely.
- As the first stage of transcochlear, transotic and combined petrosal approaches.
Surgical anatomy
Boundaries of the exposure are the middle fossa dura above, the sigmoid sinus behind, the jugular bulb below and the facial nerve in its mastoid and tympanic segments in front. Within the labyrinth, the lateral, posterior and superior semicircular canals are removed; the vestibule opens into the fundus of the IAC. At the fundus, the transverse crest separates the superior and inferior compartments, and the vertical crest (Bill's bar) separates the facial nerve (anterior) from the superior vestibular nerve (posterior)[2].
Operative steps
- Supine with the head turned away; postauricular incision.
- Complete mastoidectomy, skeletonising the sigmoid sinus, the middle fossa dura and the facial nerve (without exposing it).
- Labyrinthectomy, removing the three semicircular canals and opening the vestibule.
- Skeletonise the IAC through 270° from the porus to the fundus; identify Bill's bar and the facial nerve.
- Open the dura of the IAC and posterior fossa; remove the tumour from lateral to medial after internal debulking.
- Pack the aditus and middle ear and obliterate the defect with abdominal fat.
Complications and how to avoid them
- CSF leak through the wound or via the Eustachian tube (rhinorrhoea): close the aditus and pack the cavity with fat.
- Facial-nerve injury, reduced by early identification at the fundus and continuous monitoring[3].
- Total ipsilateral deafness (expected) and tinnitus.
- Sigmoid sinus injury and fat graft complications.
Take-home
Surgical pearls
- Find the facial nerve at the fundus, where its position is constant.
- No cerebellar retraction is needed: the bone is the retractor.
- Fat obliteration and closure of the aditus prevent most CSF leaks.
Related
References
- 1.House WF. Transtemporal bone microsurgical removal of acoustic neuromas. Arch Otolaryngol. 1964;80:597-756.
- 2.Rhoton AL Jr. The temporal bone and transtemporal approaches. Neurosurgery. 2000;47(3 Suppl):S211-S265.
- 3.Samii M, Matthies C. Management of 1000 vestibular schwannomas (acoustic neuromas): the facial nerve—preservation and restitution of function. Neurosurgery. 1997;40(4):684-694.
General education for medical professionals. It summarises published literature and is not advice for any individual patient or a substitute for supervised surgical training.