The role of the trigeminocardiac reflex in postoperative hearing function in non-vestibular schwannoma cerebellopontine angle tumors

Visualization of the tentorial innervation of human dura mater

“…These morphological findings are consistent with neurosurgical recommendations that traction or contacting the posterior part of the falx cerebri and the tentorium cerebelli should be minimized to avoid eliciting the haemodynamic fluctuations (Kemp et al 2012;Bauer et al 2005). Manipulation or cauterization of the cranial dura mater during neurosurgery can result in patients undergoing sudden onset of hypotension, bradycardia, arrhythmia, asystole or apnoea caused by the sensory nerve endings of the trigeminal nerve sending neural signals via the trigeminal ganglion to the sensory nucleus of the trigeminal nerve in the brainstem (May & Goadsby, 1999;Gharabaghi et al 2006;Acioly et al 2011;Meuwly et al 2015). Minimizing traction over the trigeminal nerve or the related zone of the dura mater is strongly emphasized in the literature on neurosurgery to prevent these trigeminocardiac reflexes (Schaller et al 2009;Etezadi et al 2013;Bauer et al 2005;Chowdhury et al 2015).…”

Functional Consequences of the Trigeminocardiac Reflex

“…Pre-and postoperative auditory function, preoperative medication, tumor size, whether the TCR occurred, and pre-and intraoperative MABP were analyzed. 114 Thus, although the impact of hypotension due to TCR on auditory function in vestibular schwannoma surgery was more evident than in non-vestibular schwannoma CPA surgery (and statistically significant as well), one cannot exclude the possibility that the same tendency may be found in the latter surgery. Preoperative functional hearing was detected in 85.7% (30) of the patients; preoperative deafness was documented in in 4 patients in the non-TCR group and 1 patient in the TCR group.…”

“…114 The authors examined the occurrence of TCR and its influence on postoperative auditory function in a consecutive series of 102 patients with non-vestibular schwannoma CPA tumors. 114 The authors examined the occurrence of TCR and its influence on postoperative auditory function in a consecutive series of 102 patients with non-vestibular schwannoma CPA tumors.…”

“…114 The authors examined the occurrence of TCR and its influence on postoperative auditory function in a consecutive series of 102 patients with non-vestibular schwannoma CPA tumors. 114 The authors concluded that TCR may be a negative prognostic factor for postoperative auditory function in patients with large non-vestibular schwannoma CPA tumors. Of the 35 patients evaluated, 4 developed the TCR intraoperatively, of whom 1 had preoperative complete hearing loss.…”

The Trigeminal Nerve

“…2,3,5 Therefore, the TCR may be refractory to the conventional methods of treatment, and the use of vasopressors is sometimes required as reported. 2,7,60,61 Several studies have shown that the TCR might be a negative prognostic factor in the preservation of hearing in vestibular 62 and nonvestibuar schwannoma surgeries. 63,64 The authors studied the impact of the TCR on postoperative auditory functioning in these patients and indicate that intraoperative changes in neurophysiologic monitoring (auditoryevoked potentials) related to the TCR predict a worsening postoperative hearing function and may serve as a valuable prognostic tool.…”