Trigeminal Nerve Repair: Is the Trigeminocardiac Reflex a Concern?

Purpose: Our hypothesis is that direct manipulation of the third and second divisions of the trigeminal nerve during microneurosurgery does not affect the incidence of trigeminocardiac reflex (TCR). The purpose of this paper was to analyze the incidence of TCR events during microneurosurgery involving the second and third divisions of the trigeminal nerve. Materials and Methods: This was a retrospective cohort study of 94 patients who underwent nerve repair of the second and third divisions of the trigeminal nerve, between July 2014 and February 2021 by a single surgeon (J. Z.). The independent variables were the trigeminal nerve branch injured, the laterality of the trigeminal nerve injury, the Sunderland classification, the ASA classification, the intraoperative narcotic(s) used, and the depth of anesthesia. The dependent variables included the occurrence of intraoperative hypercapnia, hypoxia, and TCR event. Since the data was retrospective and categorical in nature, χ² analysis was performed initially. Results: None of the patients in this retrospective cohort demonstrated intraoperative hypercapnia, hypoxia or TCR events. Initial χ² calculation was performed for the dependent variables with the trigeminal nerve groups (IAN, LN, and ION). The χ² calculation [χ² (1, n = 101)] was 0.2235. The P-value was.6364. Since there was no statistical significance found, there was no further analysis of surgical and anesthesia independent variables in the data collection. Conclusions: The zero incidence of TCR in a large number of patients provides strong evidence supporting the rejection of the hypothesis that TCR can occur during the surgical repair of peripheral trigeminal nerves.