Is cochlear implantation possible after acoustic tumor removal?

Area of Science:

• Otolaryngology
• Neurosurgery
• Auditory Neuroscience

Background:

• Hearing restoration surgery is considered for patients with bilateral acoustic tumors or unilateral hearing loss.
• Surgical options include cochlear implantation and brainstem implantation.

Observation:

• Histological examination of temporal bones from seven patients who underwent acoustic tumor removal.
• Focus on cochlear turn patency, spiral ganglion cell survival, and cochlear nerve integrity.

Findings:

• Acoustic tumor removal, particularly translabyrinthine approaches, leads to progressive cochlear osteogenesis.
• Significant degeneration of spiral ganglion cells and cochlear nerve occurs post-surgery.
• Similar findings were observed after middle fossa removal with failed hearing preservation.

Implications:

• Histologic changes in the cochlea and nerve are attributed to ischemia from disrupted blood supply during tumor removal.
• Cochlear implantation is feasible post-acoustic tumor removal if the cochlear nerve is viable (positive promontory electrical stimulation test).
• Optimal timing for cochlear implantation is during or shortly after tumor removal, before significant cochlear ossification.