The trigeminocardiac reflex (TCR) is a rare but well-described phenomenon encountered during invasive procedures involving the face, orbit, and cranial base. The reflex is characterized by the abrupt onset of hypotension, bradycardia, asystole, and dysrhythmias. With temporary cessation of the surgical procedure, vital signs typically stabilize without the need for further investigation, though anticholinergic drugs are often used to prevent prolonged hypotension and bradycardia. Two separate cases of the TCR were encountered during the percutaneous embolization of a juvenile nasopharyngeal angiofibroma with dimethylsulfoxide (DMSO) before the injection of ethylene vinyl alcohol copolymer (Onyx, ev3, Irvine, California, USA). In both cases, the injection of DMSO precipitated approximately 30 s of bradycardia/asystole, which then resolved after halting the procedure and administering anticholinergic drugs. There were no additional occurrences afterward and the patients underwent tumor excision with good recovery.
- Cranial nerve
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.
The trigeminocardiac reflex (TCR), also referred to as the trigeminovagal reflex and oculocardiac reflex, is a rare but well-described phenomenon encountered during invasive procedures involving the face, orbit, cranial base, and intracranial dura mater.1 It is a physiological response to the manipulation of any of the sensory branches of the trigeminal nerve or trigeminal ganglion.2 The TCR is characterized by the acute onset of bradycardia, dysrhythmias, asystole, arterial hypotension, apnea, and gastric hypermobility. We encountered two separate cases of TCR during the image-guided percutaneous embolization of a juvenile nasopharyngeal angiofibroma (JNA). Both events occurred suddenly after the injection of dimethylsulfoxide (DMSO) and were managed by administering anticholinergic drugs. The majority of previously reported cases occurred during invasive surgical procedures and, more recently, during an endovascular trans-arterial embolization of a dural arteriovenous fistula with Onyx.3
Our institution does not require institutional review board approval for case reports. A 17-year-old male was admitted to our institution with recurrent epistaxis and was diagnosed with a large right-sided JNA (figure 1A). The otolaryngology service desired presurgical embolization of the JNA to facilitate surgical excision of the tumor. Given our recent success with embolization of hypervascular head and neck tumors with percutaneous injection of Onyx, this approach was deemed appropriate for the patient.4
After giving informed consent, the patient was brought to the neuroangiography suite. He was placed supine on the table and placed under general anesthesia. A 20 gauge (G) spinal needle compatible with Onyx was placed within the tumor using CT fluoroscopy available in the hybrid CT angiography suite (figure 1B,C). After puncture, the needle position was confirmed as correct when blood reflux from the needle was slow but continuous. A gentle hand injection of contrast was then performed through the needle and a biplane parenchymogram was obtained. The tip of the needle was positioned close to the skull base, near the vicinity of the foramen ovale. Subsequently, DMSO was injected through the needle to prevent premature solidification of the Onyx (figure 1D,E). This precipitated a sudden onset of asystole as was notified by the anesthesiologist (figure 1F). The percutaneous injection was stopped immediately and 1 mg of atropine was administered intravenously, restoring normal heart rate and rhythm after approximately 30 s of asystole. Further injection of DMSO followed by Onyx embolization did not produce any additional abnormal cardiac responses. The percutaneous embolization with Onyx was completed and the patient underwent surgical excision of the tumor within 24 h, with good recovery.
The second case was a 15-year-old male who also underwent percutaneous embolization of his JNA before surgical excision. As in the first case, general anesthesia was used and a 20G needle placed into the JNA with the aid of CT fluoroscopy. During the injection of DMSO through the needle, this patient experienced severe bradycardia with a heart rate of 20-30 bpm that also lasted for about 30 s. In this case, intravenous glycopyrrolate was administered, with resolution of the patient's symptoms. There were no abnormal cardiac responses for the remainder of the procedure. Following the percutaneous embolization, the patient subsequently underwent surgical excision of his JNA with good recovery.
There have been no documented reports of a TCR-mediated vagal response during DMSO injection via a percutaneously placed needle. In both our cases, the TCR was activated during the percutaneous injection of DMSO into a JNA tumor, before the embolization procedure with Onyx. Previous reports have shown that TCR occurs during physical manipulation of structures surrounding the face, orbit, cranial base, and brain. Examples include craniomaxillofacial operations following trauma, periorbital surgery, strabismus surgery, endoscopic sinus surgery, pituitary surgery, tumor resections in the cerebellopontine angle or falx cerebri, and percutaneous procedures on the trigeminal ganglion.2 5–8 More recently, asystole has been described during the trans-arterial embolization of a dural arteriovenous fistula with Onyx. In that report, Lv et al hypothesized that the direct compression of the nervus spinosus in the foramen spinosum secondary to physical distension of the middle meningeal artery after Onyx injection triggered the TCR pathway.3 In our cases, the percutaneously placed needle was in the proximity of the foramen ovale, where the mandibular division of the trigeminal nerve exits the skull base. Thus, we hypothesize that the injection of DMSO directly stimulated this nerve, triggering the TCR. All vital signs preceding DMSO injection were stable.
We feel that the TCR was triggered by the injection of DMSO, and was not due to the barometric stress from the injection since this has not been seen in our experience with the percutaneous injection of contrast during the parenchymography or the injection of Onyx. According to Newton's equation the resulting shear of a fluid is directly proportional to the force applied and inversely proportional to its viscosity. In the two cases described DMSO, contrast, and Onyx were injected through a 1 ml syringe. Thus applying a similar force during each injection. Furthermore, the three fluids have a similar viscosity. Therefore the shear of the fluid should be roughly the same for the percutaneous injection of each material.
DMSO is an organic solvent used to prevent premature solidification of Onyx during embolization procedures. The neurotoxicity of DMSO has been an area of controversy, and it is conceivable the TCR in our cases occurred owing to a neurotoxic effect of DMSO. However, one study has shown that the use of DMSO with Onyx during the endovascular embolization of intracranial aneurysms failed to produce arrhythmias or decreases in heart rate and blood pressure in 39 patients.9 Thus, in our cases, the TCR was probably triggered by the forces generated during the process of DMSO injection.
As described by Schaller, the afferent pathway of the reflex arc is initiated by the stimulation of a sensory branch of the trigeminal nerve, which then transmits the signal to the sensory nucleus of the trigeminal nerve via the Gassarian ganglion.10 The afferent path then continues through the short internuncial nerve fibers of the reticular formation to synapse in the dorsal motor nucleus of the vagus nerve. The branches of the vagus nerve, which supply parasympathetic innervation to the heart, blood vessels, and abdominal organs, comprise the efferent pathway of the reflex arc.
While the TCR is unlikely to be lethal, the ensuing hemodynamic compromise warrants quick recognition by the anesthesiologist so that proper management can take place. The onset of the TCR is acute in nature and should resolve once surgical manipulation ceases. The use of local anesthetics before the procedure may prevent activation of the reflex, but once the reflex is encountered, the procedure should be halted temporarily while vagolytic drugs (eg, atropine, glycopyrrolate) or sympathomimetics are administered.11 Risk factors for developing TCR may include hypercapnia, hypoxemia, light general anesthesia, young age, prolonged and/or vigorous manipulation of the surgical site, potent narcotics such as sufentanil and alfentanil, and the use of certain β blockers and calcium channel blockers.12
Two unique cases of trigeminocardiac reflex (TCR) related to the percutaneous injection of ethylene vinyl alcohol (EVOH) copolymer (Onyx) into a juvenile nasopharyngeal angiofibroma are described.
TCR has been previously described during an endovascular trans-arterial embolization of a dural arteriovenous fistula and is a well-described phenomenon encountered during invasive procedures involving the face, orbit, cranial base, and intracranial dura mater.
TCR is a physiological response to the manipulation of any of the sensory branches of the trigeminal nerve or trigeminal ganglion.
Both our cases occurred suddenly after the injection of dimethylsulfoxide and were managed by administering anticholinergic drugs.
Physicians using EVOH copolymer (Onyx) should be aware of this phenomenon and the treatment options.
Competing interests None.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.