Difference in functional outcome of ipsilateral tinnitus after intraoperative occurrence of the trigemino-cardiac reflex in surgery for vestibular schwannomas.
OBJECTIVE
Surgical manipulation of the fifth cranial nerve in its intra- or extracranial course may lead to bradycardia or even asystole as well as arterial hypotension, a phenomenon described as the trigemino-cardiac reflex (TCR), first described by the authors previously [11]. The authors report here the impact of this reflex on post-operative ipsilateral tinnitus in patients undergoing vestibular schwannoma surgery.


METHODS
Thirty six patients scheduled for vestibular schwannoma surgery were studied retrospectively for parameters influencing the post-operative ipsilateral tinnitus function. According to the occurrence of intra- operative TCR the patients were divided into a TCR-subgroup and a non-TCR subgroup. There was no difference in tumour size between these subgroups.


RESULTS
The TCR occurred in 17% of the patients during vestibular schwannoma surgery and influenced the occurrence of post-operative ipsilateral tinnitus: the overall incidence of post-operative ipsilateral tinnitus was 22%. Sixty (60) percent of the patients in the TCR subgroup and 17% of those in the non-TCR subgroup experienced ipsilateral tinnitus postoperatively. There was no correlation between tinnitus and pre- or post-operative hearing function.


CONCLUSIONS
Hypotension after intra-operative TCR is not only a negative prognostic factor for hearing preservation but also for ipsilateral tinnitus in patients undergoing vestibular schwannoma surgery. In combination with worse hearing function after intra-operative TCR, the present finding underlines the importance of the TCR during skull base surgery in relation to improved functional outcome.
Schaller
B J
BJ
Department of Neurosurgery, University of Paris, France. skull_base_surgery@yahoo.de
Rasper
J
J
Filis
A
A
Buchfelder
M
M
D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications; D020127:Recovery of Function / Q000502:physiology; D012018:Reflex / Q000502:physiology*; D012189:Retrospective Studies; D014012:Tinnitus / Q000209:etiology* / Q000503:physiopathology; D016896:Treatment Outcome