# Trigeminocardiac Reflex Associated With Orthognathic Surgery: An Illustrative Case Report and Review of the Literature

## TL;DR

This paper reports a rare brainstem reflex during orthognathic surgery and reviews existing literature to understand its causes and outcomes.

## Contribution

The paper presents a new case of TCR during Le Fort I osteotomy and systematically reviews existing cases to identify patterns and triggers.

## Key findings

- Maxillary downfracture or mobilization were the most common triggers of TCR in orthognathic surgery.
- Despite requiring cardiopulmonary resuscitation in two cases, all patients completed their procedures without long-term adverse outcomes.
- More innocuous triggers of TCR were also identified in the reviewed cases.

## Abstract

The trigeminocardiac reflex (TCR) is a rare brainstem reflex characterized by bradycardia and hemodynamic instability secondary to stimulation of branches of the trigeminal nerve. In maxillofacial surgery, the phenomenon has been reported in orthognathic surgery, foreign body removal, and fixation of midface fractures. Despite reasonably extensive reporting of the reflex in head and neck surgery in general, the mechanism and predisposing factors are poorly understood. The primary aim of this systematic review was to explore potential contributory factors and summarize outcomes of the TCR in patients undergoing orthognathic surgery. We additionally report a case of asystole in a 21-year-old male undergoing Le Fort I osteotomy. A systematic literature search was undertaken using MEDLINE, Embase, Web of Science, Scopus, and PubMed from inception to December 24, 2025, for articles reporting patients experiencing TCR during orthognathic surgery. Studies reporting TCR cases were identified and screened by two independent reviewers. Studies reporting TCR cases were identified and screened by two independent reviewers. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed. A total of 261 studies were initially identified, documenting 17 cases in addition to the current case. Maxillary downfracture or mobilization were the most commonly reported precipitants; however, more innocuous triggers were also identified. While cardiopulmonary resuscitation was necessary in two documented cases, all cases reported completion of the procedure with no known long-term adverse outcomes. We discuss the mechanism of the reflex in relation to the identified cases and existing literature.