Evidences in Neurological Surgery and a Cutting Edge Classification of the Trigeminocardiac Reflex: A Systematic Review.

Document Type


Publication Date


Publication Title

World Neurosurg


Trigeminocardiac reflex; asystole; bradycardia; cerebellopontine angle; hypotension; neurosurgery; trigeminal nerve; Animals; Humans; Intraoperative Complications/classification; Intraoperative Complications/therapy; Neurosurgical Procedures; Postoperative Complications/prevention & control; Reflex, Trigeminocardiac


BACKGROUND: The trigeminocardiac reflex (TCR) is characterized by bradycardia, decrease of main arterial blood pressure (MABP), and sometimes, asystole during surgery. We critically reviewed TCR studies and devised a novel classification scheme for assessing the reflex.

MATERIAL: and Methods: A comprehensive systematic literature review was performed using PubMed, MEDLINE, Web of Science, EMBASE, and Scielo databases. Eligible studies were extracted based on stringent inclusion and exclusion criteria. Statistical analyses were used to assess cardiovascular variables. TCR was classified according to morphophysiological aspects involved with reflex elicitation.

RESULTS: 575 patients were included in this study. TCR was found in 8.9% of patients. The reflex was more often triggered by interventions made within the anterior cranial fossa. The maxillary branch (type II in the new classification) was the most prevalent nerve branch found to trigger the TCR. Heart rate (HR) and mean arterial blood pressure (MABP) were similarly altered (p = 0.06; F = 0.3912809), covaried with age (p = 0.012; F = 9.302), and inversely correlated to each other (r = -0.27).

CONCLUSION: TCR is a critical cardiovascular phenomenon that must be quickly identified, efficiently classified, and should trigger vigilance. Prompt therapeutic measures during neurosurgical procedures should be carefully addressed to avoid unwanted complications. Accurate categorization using the new classification scheme will help to improve understanding and guide the management of TCR in the perioperative period.

Clinical Institute

Neurosciences (Brain & Spine)