Unusual Appearance of Trigemino-Cardiac Reflex During Cerebellopontine Angle Surgery

Intra-operative hypertension as a predictor of surgical outcomes in microvascular decompression surgery for trigeminal neuralgia

PURPOSE

The trigeminocardiac reflex (TCR) has traditionally been characterized by a sudden decrease in heart rate, asystole, or hypotension during the manipulation of the trigeminal nerve (MTN) or its branches. While this classical TCR is well-documented, there is limited literature on alternative forms of TCR, such as the development of intraoperative hypertension (HTN) or tachycardia, and the underlying pathogenesis. Furthermore, a gap exists in understanding the correlation between intraoperative blood pressure readings and postoperative outcomes, particularly regarding pain relief in patients with trigeminal neuralgia (TN). Our study aims to examine intraoperative blood pressure trends during microvascular decompression (MVD) for TN and assess their impact on postoperative outcomes.

METHODS

We selected 90 patients who underwent MVD for TN treatment. Blood pressure and heart rate were recorded both preoperatively and during the procedure, specifically during the MTN period, using an arterial line. The Barrow Neurological Institute (BNI) Pain Scale was calculated for all patients both pre- and post-operatively to evaluate pain relief after surgery.

RESULTS

The mean age of the patients was 61.0 ± 12.35 years, with 64.4% being females. Classical TCR (hypotension) was observed in only 2.2% of patients, whereas 80% of patients developed hypertension (≥ 140/90) during MTN. The mean preoperative systolic blood pressure was 128 ± 22.25, and the mean intraoperative systolic blood pressure during MTN was 153.1 ± 20.2. An analysis of covariance, utilizing either preoperative BNI or duration of symptoms as covariate variables, revealed a statistically significant association between intraoperative HTN and postoperative BNI. A linear regression model demonstrated that intraoperative HTN following MTN significantly predicted a lower postoperative BNI score (p = 0.006).

CONCLUSIONS

Intraoperative HTN during MTN, an observed yet underexplored phenomenon, demonstrated a correlation with improved postoperative outcomes. Furthermore, it is recommended to conduct additional investigations into potential neurovascular conflicts in patients not manifesting intraoperative HTN following MTN. A comprehensive understanding of TCR, encompassing its various forms, is vital for optimizing surgical management. This study underscores the imperative for further research to unravel the mechanisms linking intraoperative HTN to surgical outcomes in TN patients.

The Effect of Atropine on Trigeminocardiac Reflex-induced Hemodynamic Changes During Therapeutic Compression of the Trigeminal Ganglion

BACKGROUND

Percutaneous compression of the trigeminal ganglion (PCTG) can induce significant hemodynamic perturbations secondary to the trigeminocardiac reflex (TCR). The aim of this study was to investigate the effect of atropine pretreatment on hemodynamic responses during PCTG for trigeminal neuralgia.

MATERIALS AND METHODS

A total of 120 patients who received PCTG were randomly assigned to control and atropine groups that were pretreated with saline (n=60) and atropine 0.004 mg/kg intravenously (n=60), respectively. Heart rate (HR) and mean arterial pressure (MAP) were measured at 9 timepoints from before induction of anesthesia until the end of the PCTG procedure; the incidence of TCR was also observed.

RESULTS

HR was higher in the atropine compared with control group from the time of skin puncture with the PCTG needle until after the procedure was completed (P<0.05). MAP was also higher in the atropine compared with control group, but only at entry of the needle into the foramen ovale until 1 minute after trigeminal ganglion compression (P<0.05). HR was reduced in both groups during entry of the needle into the foramen ovale and during ganglion compression, but less so in the atropine compared with the control group (P<0.05). MAP increased during PCTG compared with baseline in both groups, but with a larger increase in the atropine group (P<0.05). Two and 52 cases in the control group, and 6 and 1 cases in the atropine group, exhibited a TCR during entry of the needle into the foramen ovale and at ganglion compression, respectively (P<0.05).

CONCLUSION

Pretreatment with atropine was effective in most patients at minimizing abrupt reduction in HR during PCTG.

A rare appearance of the trigeminocardiac reflex during resection of posterior parasagittal meningioma

Background:

Although a well-recognized phenomenon of the tentorium and posterior fossa, the trigeminocardiac reflex (TCR) has been rarely reported during surgery involving the posterior falx cerebri.

Case Description:

We present the case of a 63-year-old woman who underwent repeat resection of an atypical parasagittal meningioma involving the posterior falx. During resection, TCR was repeatedly elicited during manipulation and coagulation of the falx. Air embolism and cardiac etiologies were initially considered while TCR was not suspected, given the location. Ultimately, TCR was recognized when asystole self-resolved upon cessation of stimulus and due to its reproducibility.

Conclusion:

Awareness by the anesthesiologist and neurosurgeon of the possibility of TCR during falcine procedures can help with rapid identification to avoid a potentially catastrophic outcome.