Intraoperative Brainstem Auditory Evoked Potential Observations After Trigeminocardiac Reflex During Cerebellopontine Angle Surgery

Adult Male Adolescent Epidermal Cyst Heart Cerebellopontine Angle Prognosis 03 medical and health sciences Treatment Outcome 0302 clinical medicine Hearing Monitoring, Intraoperative Reflex Evoked Potentials, Auditory, Brain Stem Audiometry, Pure-Tone Humans Anesthesia Female Trigeminal Nerve Cerebellar Neoplasms Meningioma Neurilemmoma
DOI: 10.1097/ana.0b013e3181eac551 Publication Date: 2010-08-11T11:53:57Z
ABSTRACT
The occurrence of trigeminocardiac reflex (TCR) is known to be a negative prognostic factor for hearing preservation in cerebellopontine angle tumor surgery. Our study was conducted to investigate brainstem auditory evoked potential (BAEP) changes after this reflex in cerebellopontine angle tumor surgery and to evaluate their impact on postoperative hearing function.Five of 102 consecutive patients had an intraoperative TCR (4.9%) and were retrospectively evaluated for the intraoperative BAEP changes after TCR and postoperative auditory function (7 to 10 d after surgery). One of the 5 patients was preoperatively deaf and therefore excluded from this analysis.Four patients with preoperative functional hearing developed one or more episodes of TCR. Intraoperative BAEP was maintained in 1 patient, whereas in 3 cases an acute intraoperative BAEP deterioration occurred within 2:04 to 3:27 minutes (mean 2:44 min) after TCR with increased wave latency, decreased wave amplitude, and even wave loss. Two patients had deteriorated BAEP waves until the surgical completion and were postoperatively deaf.Although no direct cause-effect relationship has yet been shown, we suggest TCR as an additional event that may cause BAEP changes. The observed BAEP alterations occurred minutes rather than seconds after the TCR incident leading to both temporary and permanent wave deterioration. This association of BAEP deterioration and TCR occurrence, however, remains yet to be proven justifying further study in the field.
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