Extended Middle Cranial Fossa Approach for Placement of Auditory Brainstem Implants

Traditionally, auditory brainstem implants (ABIs) have been placed via the translabyrinthine or retrosigmoid approaches. In select patients, a modified extended middle cranial fossa (xMCF) approach with tentorial ligation may be advantageous for vestibular schwannoma (VS) resection and auditory rehabilitation. This manuscript describes the application of this modification of the MCF approach for simultaneous VS resection and ABI placement.

Patients with neurofibromatosis type 2, profound bilateral sensorineural hearing loss, single functioning sigmoid/jugular venous system, and giant (>4 cm) VS.

Simultaneous VS resection and ABI placement via a modified xMCF approach with tentorial ligation.

Extent of tumor removal and brainstem decompression, access to lateral recess of the fourth ventricle, functional hearing improvement, surgical complications.

Two patients met indications and underwent surgery. There were no immediate or delayed surgical complications. Both had subtotal tumor removal with significant decompression of the brainstem and ABI placement. One patient achieved voice and environmental sound awareness at 35 to 55 dbHL across frequencies. The second patient presented with failure to thrive and multiple lower cranial neuropathies in addition to the above-listed indications. She was hospitalized multiple times after surgery due to failure to thrive and recurrent aspiration pneumonia. Her device was never activated, and she expired 1 year after surgery.

The xMCF with tentorial ligation is an additional approach for tumor resection and ABI placement in selected patients with neurofibromatosis type 2. Future studies will further define when this approach is most applicable as well as the challenges and pitfalls.