Vestibular schwannoma and hearing preservation: Usefulness of level specific CE-Chirp ABR monitoring. A retrospective study on 25 cases with preoperative socially useful hearing

Luciano Mastronardi; Ettore Di Scipio; Guglielmo Cacciotti; Raffaelino Roperto

doi:10.1016/j.clineuro.2018.01.011

Vestibular schwannoma and hearing preservation: Usefulness of level specific CE-Chirp ABR monitoring. A retrospective study on 25 cases with preoperative socially useful hearing

Clin Neurol Neurosurg. 2018 Feb:165:108-115. doi: 10.1016/j.clineuro.2018.01.011. Epub 2018 Jan 10.

Authors

Luciano Mastronardi¹, Ettore Di Scipio², Guglielmo Cacciotti², Raffaelino Roperto²

Affiliations

¹ San Filippo Neri Hospital, Department of Neurological Sciences, Division of Neurosurgery and *Unit of Neurophysiopathology, Roma, Italy. Electronic address: mastro@tin.it.
² San Filippo Neri Hospital, Department of Neurological Sciences, Division of Neurosurgery and *Unit of Neurophysiopathology, Roma, Italy.

PMID: 29334639
DOI: 10.1016/j.clineuro.2018.01.011

Abstract

Background and objectives: Decision-making regarding the therapy of vestibular schwannoma (VS) changed over the last decades, during which curative microsurgery has been promoted. Goals of VS microsurgery are: extensive resection, facial nerve (FN) preservation and, in selected cases, hearing preservation (HP). The aim of this study is to evaluate postoperative HP with reference to tumor size in patients operated on with Level Specific (LS)-CE-Chirp® ABR monitoring.

Patients and methods: Twentyfive consecutive patients with socially useful hearing (SUH) underwent VS microneurosurgery by retrosigmoid (RS) approach. Selection criteria were: pure tone audiogram <50dB loss and speech discrimination score >50% (50/50 criterion; AAO-HNS class A-B). In relation to maximum diameter, we identified 2 size-groups: A) ≤2cm (13 cases); B) >2cm (12 cases). HP attempt was assisted by intraoperative ABR evoked by LS CE-Chirp® acoustic stimuli.

Results: Mean age was 44,3 years (20-64); average maximum diameter 2,04cm (8 40mm). Total and nearly-total (>95%) resection was possible in all. Mortality and major morbidity were zero. In all, FN was anatomically and functionally preserved; in 10 an incomplete FN deficit (House-Brackmann II and III) was followed by complete recovery (House-Brackmann I). SUH preservation rate was 52%, with significant differences in relation to size: 61,5% group A and 41,7% group B (p = 0,014). Postoperative AAO-HNS C (serviceable) hearing was observed in 36%, deafness in 12%.

Conclusion: Microsurgery represents a valid therapeutic option for small growing VS with SUH. Our data confirm that RS removal of VS with intraoperative ABR monitoring allows good rate of SUH preservation, especially if maximum diameter does not exceed 2cm. LS-CE-Chirp ABR represent a safe and effective method for monitoring cochlear nerve, with fast and clear intraoperative neurophysiological feedback.

Keywords: ABR; Facial nerve preservation; Hearing preservation; LS CE-Chirp; Microsurgery; Retrosigmoid approach; Vestibular schwannoma.

MeSH terms

Adult
Audiometry, Pure-Tone
Evoked Potentials, Auditory, Brain Stem*
Female
Follow-Up Studies
Hearing*
Humans
Magnetic Resonance Imaging
Male
Microsurgery / adverse effects
Microsurgery / methods*
Middle Aged
Monitoring, Intraoperative / methods*
Neuroma, Acoustic / diagnostic imaging
Neuroma, Acoustic / surgery*
Neurosurgical Procedures / adverse effects
Neurosurgical Procedures / methods*
Peripheral Nervous System Neoplasms / diagnostic imaging
Peripheral Nervous System Neoplasms / surgery*
Postoperative Complications / epidemiology
Retrospective Studies
Speech Perception
Treatment Outcome
Young Adult