Universität zu Köln

Hedjrat Yazdi, Ali Reza (2025). Postoperative Cochlear Obliteration after Retrosigmoid Approaches in Patients with Vestibular Schwannoma. PhD thesis, Universität zu Köln.

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Abstract

Vestibular schwannomas (VSs) are the most common tumors located in the cerebellopontine angle (CPA). While facial nerve function is often preserved, the cochlear nerve is frequently affected. Magnetic resonance imaging (MRI) is the gold standard for diagnosis. Treatment options include observation, microsurgical resection, fractionated radiotherapy, and radiosurgery. The main goals of surgery are to preserve facial nerve function and, ideally, cochlear nerve function. However, hearing loss is often unavoidable due to the vulnerability of the cochlear nerve. To restore hearing postoperatively, cochlear implants (CI) and auditory brainstem implants (ABI) are available. CI is the preferred option when the cochlear nerve is preserved and the cochlea remains patent. However, cochlear obliteration presents a challenge for CI implantation. It is assumed that the surgical approach (retrosigmoid vs. translabyrinthine) may influence the risk of cochlear obliteration. This monocentric, retrospective study evaluated the frequency of cochlear obliteration after retrosigmoid VS surgery using high-resolution, T2-weighted MRI scans. Cochlear obliteration was observed in 32% of cases. Factors such as age, tumor size, operation duration, and reoperation were not significantly associated with higher obliteration rates. However, obliteration occurred more frequently in female patients and was significantly associated with obliteration of the semicircular canals. The proximity of these canals to the posterior lip of the internal auditory canal may contribute to inner ear susceptibility. Future studies should explore surgical technique differences and the ideal timing for CI implantation before cochlear obliteration develops.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Hedjrat Yazdi, Ali Reza hedjrat@online.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-785821
Date:	2025
Language:	English
Faculty:	Faculty of Medicine
Divisions:	Faculty of Medicine > Neurochirurgie > Klinik für Allgemeine Neurochirurgie
Subjects:	Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language Cochlear Obliteration English Vestibular Schwannoma English Retrosigmoid approaches English Cochlear Implantat English
Date of oral exam:	10 April 2025
Referee:	Name Academic Title Behr, Robert Andreas Josef Prof. Dr. med. Lang-Roth, Ruth Priv. -Doz. Dr. med.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/78582