Bradycardia during elevation of a zygomatic arch fracture

Cranial Nerve Injuries in Orthognathic Surgery: A Review of Literature

ABSTRACT

Orthognathic surgery is increasingly utilized to correct facial deformities and dental malocclusions, as well as to enhance facial aesthetics. Significant advancements in surgical planning and execution have made it more widespread and accessible. However, unfavorable outcomes or complications can occur, leading to potentially severe and possibly long-term consequences, such as cranial nerve injuries. This literature review investigates the cranial nerve complications associated with orthognathic surgery. We conducted an extensive search across available databases, analyzing relevant studies published up to September 30, 2023. Two authors independently selected articles for full-text review based on their titles and abstracts. The eligible studies reported cranial nerve injuries in individuals who had undergone orthognathic surgery. Our findings highlight the risk of cranial nerve injuries, their possible mechanism, management, and outcomes. It is imperative for surgeons to remain vigilant and informed and to communicate such information during preoperative patient consultation.

Perioperative adverse cardiac events in maxillofacial surgery: A systematic review and meta-analysis

Background and Aims

Maxillofacial surgeries, including procedures to the face, oral cavity, jaw, and head and neck, are common in adults. However, they impose a risk of adverse cardiac events (ACEs). While ACEs are well understood for other non-cardiac surgeries, there is a paucity of data about maxillofacial surgeries. This systematic review and meta-analysis report the incidence and presentation of perioperative ACEs during maxillofacial surgery.

Methods

We included primary studies that reported on perioperative ACEs in adults. To standardise reporting, ACEs were categorised as 1. heart rate and rhythm disturbances, 2. blood pressure disturbances, 3. ischaemic heart disease and 4. heart failure and other complications. The primary outcome was ACE presentation and incidence during the perioperative period. Secondary outcomes included the surgical outcome according to the Clavien-Dindo classification and trigeminocardiac reflex involvement. STATA version 17.0 and MetaProp were used to delineate proportion as effect size with a 95% confidence interval (CI).

Results

Twelve studies (34,227 patients) were included. The incidence of perioperative ACEs was 2.58% (95% CI 1.70, 3.45, I2 = 96.17%, P = 0.001). Heart rate and rhythm disturbances resulted in the greatest incidence at 3.84% among the four categories. Most commonly, these ACEs resulted in intensive care unit admission (i.e. Clavien-Dindo score of 4).

Conclusion

Despite an incidence of 2.58%, ACEs can disproportionately impact surgical outcomes. Future research should include large-scale prospective studies that may provide a better understanding of the contributory factors and long-term effects of ACEs in patients during maxillofacial surgery.

Evaluation of Trigeminocardiac Reflex in Patients Undergoing Elevation of Zygomatic Fractures

Aim

Trigeminocardiac reflex (TCR) manifests as typical hemodynamic perturbations including a sudden lowering of heart rate, mean arterial blood pressure (MABP), cardiac arrhythmias, and asystole. In literature, TCR has been seen during ocular surgeries, Lefort fractures, and craniofacial surgeries. However, the prevalence of the TCR has not been studied in zygomatic complex fractures . The aim of this study was to assess the prevalence of TCR in patients undergoing elevation with/without fixation of zygomatic complex fractures and isolated zygomatic arch fractures under local anesthesia and general anesthesia and to evaluate the prevalence of TCR in different age groups.

Materials and methods

The study comprised 26 participants diagnosed with zygomatic fractures indicated for surgical intervention. The aim of the study was to find the prevalence of TCR in patients undergoing surgical intervention (elevation of zygomatic complex fractures with/without fixation) under local anesthesia and general anesthesia. The heart rate and blood pressure were measured preoperatively, intraoperatively and postoperatively.

Results

Variation in heart rate was seen in patients undergoing surgery under local anesthesia and general anesthesia. However, a decrease in the heart rate i.e., bradycardia was noted intra-operatively in 75% of the patients operated under local anesthesia. The prevalence of TCR was noted intra-operatively in 23% of cases operated under general anesthesia. No significant changes were seen in the blood pressure of the patients.

Conclusion

In our study, we found out that the prevalence of TCR was more in the patients operated under local anesthesia i.e., 75% of patients. Out of the patients operated under general anesthesia i.e., 23% of patients showed TCR. No significant variations in blood pressure were observed in patients operated under local anesthesia or general anesthesia. The prevalence of TCR was found more often in the age group of 31-45 years in our study.

Territorial and Extraterritorial Trigeminocardiac Reflex: A Review for the Neurosurgeon and a Type IV Reflex Vignette

The trigeminocardiac reflex (TCR) is a complex and, sometimes, fatal event triggered by overstimulation of the trigeminal nerve (TN) and its territorial and spinal cord branches. We reviewed and compiled for the neurosurgeon key aspects of the TCR that include a novel and straightforward classification, as well as morphophysiology, pathophysiology, neuromonitoring and neuromodulation features. Further, we present intraoperative data from a patient who developed extraterritorial, or type IV, TCR while undergoing a cervical surgery. TCR complexity, severity and unwanted outcomes indicate that this event should not be underestimated or overlooked in the surgical room. Timely TCR recognition in surgical settings is valuable for applying effective intraoperative management to prevent catastrophic outcomes.

Reflejo trigémino cardíaco durante artroscopia de la articulación temporomandibular. Reporte de caso clínico

Introducción: el reflejo trigémino cardíaco es una respuesta fisiológica parasimpática repentina, que ocasiona alteraciones cardiovasculares importantes durante la estimulación nerviosa en el trayecto del V par craneal, generalmente ocurre al realizar procedimientos quirúrgicos en cirugía oral y maxilofacial, neurocirugía, oftalmología y dermatología. La artroscopia de la articulación temporomandibular ha sido tradicionalmente considerada un procedimiento quirúrgico seguro, mínimamente invasivo, aun así, esta técnica no está exenta de complicaciones neuro y cardiovasculares. Objetivo: presentar un caso clínico que durante una artroscopia de la articulación temporomandibular en la fase de instrumentación del espacio articular superior, y que, bajo monitoreo continuo del anestesiólogo, reportó una bradicardia súbita. Conclusión: el diagnóstico intraoperatorio de reflejo trigémino cardíaco, fue descrito por el servicio de anestesiología recibiendo un tratamiento farmacológico temprano para esta condición, lo que permitió obtener una adecuada evolución trans y postoperatoria.La artroscopia de la articulación temporomandibular ha sido tradicionalmente considerada un procedimiento quirúrgico seguro, mínimamente invasivo, aun así, esta técnica no está exenta de complicaciones.El objetivo de este artículo es presentar un caso clínico que durante una artroscopia de la articulación temporomandibular en la fase de instrumentación del espacio articular superior sufrió una bradicardia súbita, con un diagnóstico intraoperatorio de reflejo trigémino cardíaco, recibiendo un tratamiento temprano por parte del servicio de anestesiología de esta condición, obteniendo una adecuada evolución trans y postoperatoria.

Recurrent Atrial Tachyarrhythmia Triggered by Percutaneous Balloon Rhizotomy of the Trigeminal Nerve

Stimulation of sensory branches of the trigeminal nerve is known to cause sudden bradycardia (trigeminocardiac reflex). However we report a case where percutaneous balloon rhizotomy of the trigeminal ganglion provoked atrial tachyarrhythmias during two separate treatments. On both occasions the patient was treated with antiarrhythmic drugs and reverted to sinus rhythm within days. Our case demonstrates that surgery involving the trigeminal nerve may cause variable cardiovascular effects that are often clinically significant. Possible mechanisms and management of arrhythmias in this setting are discussed.

Trigeminal Cardiac Reflex and Cerebral Blood Flow Regulation

The stimulation of some facial regions is known to trigger the trigemino-cardiac reflex: the main stimulus is represented by the contact of the face with water. This phenomenon called diving reflex induces a set of reactions in the cardiovascular and respiratory systems occurring in all mammals, especially marine (whales, seals). During the immersion of the face in the water, the main responses are aimed at reducing the oxygen consumption of the organism. Accordingly reduction in heart rate, peripheral vasoconstriction, blood pooling in certain organs, especially the heart, and brain and an increase in blood pressure have been reported. Moreover, the speed and intensity of the reflex is inversely proportional to the temperature of the water: more cold the water, more reactions as described are strong. In the case of deep diving an additional effect, such as blood deviation, has been reported: the blood is sequestered within the lungs, to compensate for the increase in the external pressure, preventing them from collapsing. The trigeminal-cardiac reflex is not just confined to the diving reflex; recently it has been shown that a brief proprioceptive stimulation (10 min) by jaw extension in rats produces interesting effects both at systemic and cerebral levels, reducing the arterial blood pressure, and vasodilating the pial arterioles. The arteriolar dilation is associated with rhythmic diameter changes characterized by an increase in the endothelial activity. Fascinating the stimulation of trigeminal nerve is able to activate the nitric oxide release by vascular endothelial cells. Therefore, the aim of this review was to highlight the effects due to trigeminal cardiac reflex induced by a simple mandibular extension. Opposite effects, such as hypotension, and modulation of cerebral arteriolar tone, were observed, when these responses were compared to those elicited by the diving reflex.

Recurrent asystole as an electrocardiographic artifact during microdebrider use in functional endoscopic sinus surgery

INTRODUCTION

Electrocardiographic (EKG) artifacts can lead to unnecessary treatment and costly diagnostic workup. Two previous studies reported a ventricular tachycardia artifact as a result of microdebrider malfunction. In this study, we report the first case of EKG artifacts that mimick asystole from microdebrider use during functional endoscopic sinus surgery (FESS).

CASE

A healthy 19-year-old woman presented with chronic rhinosinusitis, nasal polyposis, and a deviated nasal septum. She was scheduled for a bilateral FESS and septoplasty. During surgery, the microdebrider was changed after 1 hour. While using the second microdebrider, the EKG monitor showed three distinct asystolic events, all lasted approximately 3 seconds. The EKG tracing returned to normal sinus rhythm every time the microdebrider was stopped. The patient's oxygen saturation remained at 100%, and blood pressure remained stable during the episodes. The procedure was aborted, and an extensive cardiology workup was performed, which returned negative results. Biomedical engineering investigated the microdebrider and found a far greater than expected chassis leak, which likely caused electrical interference. Six months later, the patient underwent a right-sided FESS and revision left frontal FESS. There were no EKG abnormalities during the second surgery.

DISCUSSION

Although other EKG artifacts have been reported in the literature, this is the first case report of an artifact that mimicked asystole that stemmed from microdebrider use. Improved awareness of this potential EKG artifact for both the surgeon and the anesthesiologist may prevent an unnecessary costly workup.

Trigemino-Cardiac Reflex: A Phenomenon Neglected in Maxillofacial Surgery?

BACKGROUND

Trigemino-cardiac reflex is a physiologic response of the body to pressure effects in the region of distribution of the trigeminal nerve. Oral and maxillofacial surgical procedures can induce the development of this reflex, which leads to significant changes in the heart rate and sinus rhythms. This study intends to evaluate the effects of this reflex in patients with facial fractures and its subsequent management.

PATIENTS AND METHODS

A total of thirty-seven patients with facial fractures who reported to the Department of Oral and Maxillofacial Surgery at Basaveswar Teaching and General Hospital, Gulbarga during a period from July 2015-March 2016 were considered for the study.

RESULTS

A male preponderance is observed with the most susceptible age group being 21-30 years. Twenty-three patients sustained mid-facial fractures alone, nine patients had isolated mandible fractures and five patients had fractures of both the mid-face and mandible. A relative bradycardia was observed in the patients with mid-facial trauma, both at the time of presentation and also during the surgical reduction of midfacial fractures which improved after completion of procedure in most of the patients. However, in two patients, the bradycardia progressed to a cardiac asystole during midface manipulation which required immediate halt of the procedure and intravenous administration of atropine.

CONCLUSION

Trigeminocardiac reflex though physiologic, which usually tends to subside without complications is not to be neglected in the surgeries of the maxillofacial skeleton. A propensity for unforeseen complications due to this reflex has to be avoided by meticulous monitoring of the ECG.

A Review of Cardiovascular Autonomic Control in Cluster Headache

OBJECTIVE

This review aims to evaluate existing literature concerning cardiovascular autonomic function and CH. Suggestions about future research are offered and known difficulties in investigating the autonomic nervous system in cluster headache are discussed.

BACKGROUND

Little is known of the pathophysiological mechanisms behind cluster headache. Cranial autonomic features are an inherent and diagnostic feature; however, a number of studies and clinical observations support the involvement of systemic autonomic control in its pathophysiology. Further, cluster headache attacks are apparently more easily triggered during periods of parasympathetic dominance. A better understanding of this interaction may provide insight into central autonomic regulation and its role in cluster headache.

METHODS

A PubMed search was performed in April 2015 using the search terms "cluster headache," "cardiovascular," "autonomic nervous system," and "cardiac." References of identified articles were also searched for relevant articles. Studies were included if they contained data on cardiovascular or autonomic responses to autonomic tests, induced or spontaneous attacks.

RESULTS

In total, 22 studies investigating cardiac autonomic control in cluster headache were identified. Three overall categories of investigations exist: (1) Those studying changes in heart rate, blood pressure, and electrocardiographic changes; (2) those employing various clinical autonomic tests; and finally (3) those using spectral and nonlinear analysis of heart rate variability. Although not completely congruent, overall, results suggest ictal hyperactivation of the parasympathetic branch and a sympathetic deficit. Subclinical autonomic dysregulation is also present in the pain-free state.

CONCLUSION

Cardiac autonomic control is subclinically affected in cluster headache. The changes could be attributed to the suggested central dysregulation present in this disorder.

Trigeminocardiac reflex in neurosurgical practice: Report of two new cases

BACKGROUND

Systemic hypotension, cardiac dysrhythmia especially bradycardia, apnea, and gastric hypermotility occurring presumably after stimulation of any of the sensory branches of trigeminal nerve are coined as trigeminocardiac reflex (TCR). Neither enough is known about the predisposing factors in relation with the intraoperative occurrence of this life threatening reflex, nor about the exact pathophysiology of its brain stem pathway. ENCOUNTERING TWO CASES OF BRADYCARDIA AND HYPOTENSION DURING SURGERY ENCOURAGED THE AUTHORS TO: (1) report these two cases and review similar reports in the relevant literature, (2) discuss the suggested mechanisms for such an event, and (3) report the result of a prospective cohort of precisely checked cases in a sister article, to remind the younger neurosurgical community of a possible and bothering even mortal, but avoidable complication in their everyday practice.

CASE DESCRIPTION

The first case was a 71-year-old male who developed bradycardia and hypotension while packing his large sella tursica with autologous fat after removing a large nonfunctional pituitary adenoma transsphenoidally to prevent cerebrospinal fluid leakage. The changes in his vital signs were detected and controlled rapidly. The second case was a 52-year-old female who underwent right pterional craniotomy for right clinoidal meningioma. She developed severe bradycardia and hypotension after skin closure completed and just when the subgaleal drain was connected to the aspirating bag and negative pressure maintained in the subgaleal region. Both cases could be managed successfully after on time detection of such life threatening complication and proper management.

CONCLUSION

WE DO NOT INTEND ONLY TO ADD TWO NEW CASES OF TCR OCCURRING IN THE PERIOPERATIVE PERIOD IN NEUROSURGICAL PRACTICE, BUT WE WISH TO RAISE THE QUESTION: (a) what could be the predisposing factors for development of such issue for better handling of the problem and (b) stress upon careful continuous mapping of the vital signs during surgery and even till very late after operation.

Trigeminocardiac Reflex: A Reappraisal with Relevance to Maxillofacial Surgery

PURPOSE

The purpose of this paper was to undertake a review of literature on trigeminocardiac reflex in oral and maxillofacial online data-base and discuss the pathophysiology, risk factor assessment, presentation of the reflex, prevention, management with emphasis on the role of the attending anaesthetist and the maxillofacial surgeon.

MATERIALS AND METHODS

The available literature relevant to oral and maxillofacial surgery in online data-base of the United States National Library of Medicine: Pubmed (http://www.ncbi.nlm.nih.gov/pubmed/) was searched. The inclusion criterion was to review published clinical papers, abstracts and evidence based reviews on trigeminocardiac reflex relevant to oral and maxillofacial surgery.

RESULTS

Sixty-five articles were found with the search term "trigeminocardiac reflex" in the literature searched. Eighteen articles met the inclusion criteria for this study. The relevant data was extracted, tabulated and reviewed to draw evidence based conclusions for the management of trigeminocardiac reflex.

CONCLUSIONS

Conclusions were drawn and discussed based on the reviewed maxillofacial literature with emphasis on the anaesthetist's and the surgeon's role in the management of this detrimental event in maxillofacial surgical practice.

New protocol to prevent TMJ reankylosis and potentially life threatening complications in triad patients

The management of patients with the triad of temporomandibular joint (TMJ) ankylosis, micrognathia and obstructive sleep apnea syndrome is challenging for the oral and maxillofacial surgeon because it involves achieving the desired oral opening, correction of micrognathia, and correction of the obstructed airway. Seven of the authors' triad patients, in whom only the release of ankylosis was performed, developed bradycardia and respiratory distress during postoperative jaw physiotherapy, leading to their non-compliance for active jaw physiotherapy and subsequent reankylosis. This paper suggests a new surgical protocol for the management of patients with the triad, to achieve correction of the obstructed airway, relief of the respiratory distress symptoms, correction of micrognathia and restricted mouth opening. It also provides a logical reason for the occurrence of bradycardia following ankylosis release and its potential role in TMJ reankylosis. It emphasizes that the occurrence of bradycardia in triad patients during jaw exercises is dictated by the severity of their apnea-hypopnea index and the degree of narrowing of their posterior airway space. The recognition and prevention of this by the new protocol is discussed in 7 patients.

A unique case of asystole secondary to facial injury

Bradycardia has been reported during intraoperative settings of craniofacial, cerebropontine angle and trigeminal ganglion surgeries (Schaller et al. (2009, 1999); Parbhakar et al. (2009); Koerbel et al. (2005); Roberts et al. (1999)). It is also commonly seen in children undergoing orbital and maxillary fractures repair. This mechanism has been described as the trigeminocardiac reflex (TCR) (Schaller et al. (2009, 2004); Kim et al. (2000); Lang et al. (1991); Van Brocklin et al. (1982)). We report an unusual case of posttraumatic bradycardia and recurrent asystole in a previously healthy adult patient from possible TCR in the absence of any surgical intervention to the head and orbital area.

Sudden asystole due to trigeminocardiac reflex during transsphenoidal surgery for pituitary tumor

BACKGROUND

A sudden attack of an asystolic phenomenon is an extremely rare event during transsphenoidal surgery (TSS). It may be caused by an extreme type of trigeminocardiac reflex (TCR) during the manipulation of the trigeminal nerve or its innervated structures.

CASE DESCRIPTION

We report two cases of sudden asystole and a case of severe bradycardia due to TCR during TSS. All patients were managed successfully by cessation of the surgical manipulation or with the injection of an anticholinergic agent.

CONCLUSIONS

Although TCR occurs rarely and usually is self-limiting, surgeons should be cautious of its occurrence, especially when manipulating the cavernous sinus during TSS. This allows the early detection and appropriate treatment of this manifestation. Stopping the surgical procedure as soon as TCR occurs is likely to normalize the vital parameters. In addition, if further manipulations are inevitable, the administration of anticholinergic medication should be considered cautiously to improve surgical outcomes.

Determination of trigeminocardiac reflex during rhinoplasty

In most rhinoplasty procedures, osteotomies are usually required. The osteotomy areas are innervated by sensory branches of the trigeminal nerve. The trigeminocardiac reflex (TCR) is clinically defined as the sudden onset of parasympathetic activity during stimulation of the trigeminal nerve. When an osteotomy is performed or external pressure is applied over the nasal bone, the infraorbital nerve may send signals via this nerve. The aim of this prospective study is to determine the blood pressure changes and occurrence of TCR during rhinoplasty. one hundred and eight patients were enrolled into the study. Lidocaine and adrenaline combination (LAC) was injected only into the left lateral osteotomy sites. All patients underwent median, right-side, then left-side lateral osteotomies and nasal pyramid infracture. The haemodynamic changes were recorded. A 10% or more decrease in the heart rate from baseline was considered a TCR. TCR was detected in nine patients following lateral osteotomies and nasal pyramid infracture procedures (8.3%). The authors determined that LAC injection prior to osteotomy did not prevent TCR. Manipulation at or near the infraorbital nerve during rhinoplasty may cause TCR, even if local anaesthetic infiltration is used.

Trigemino-cardiac reflex during orbital floor reconstruction: a case report and review

Trigemino-cardiac reflex is occurrence of hypotension and bradycardia upon surgical manipulation of areas supplied by the trigeminal nerve, and has been reported during craniofacial maxillofacial and ocular surgeries. Communication between the anaesthetic and surgical team is essential, and cessation of the precipitating stimulus is the first and most important therapeutic step. We report a case of immediate, reproducible, and reflexive response of Bradycardia and dysrhythmia upon manipulation of orbital fracture during orbital floor reconstruction in a 65-year-old man. Upon recognition of the reproducible relationship between falcine stimulation and increased vagal tone, the patient was given atropine in an effort to block cholinergic hyperactivity. After atropine administration, no further dysrhythmias occurred and surgery was carried uneventfully.

Classification of potential risk factors for trigeminocardiac reflex in craniomaxillofacial surgery

PURPOSE

Trigeminocardiac reflex (TCR) in craniomaxillofacial surgery can lead to severely life-threatening situations. At least mild forms are probably much more common than the existing surgical literature suggests. Therefore, the aim of this presentation of cases and literature review was to evaluate the predisposing factors leading to a classification of risk factors for potential TCR and to give information concerning preventive measures and management procedures.

PATIENTS AND METHODS

All surgery reports from the Department of Cranio-Maxillofacial and Oral Surgery in the University Hospital in Zurich between 2003 and 2008 were searched for severe intraoperative cardiovascular complications, and a literature review was performed for publications concerning asystole or bradycardia during maxillofacial surgical procedures.

RESULTS

Three incidents were revealed in which severe bradycardia--in 2 cases followed by asystole--had occurred. All incidents were successfully managed.

CONCLUSION

All craniomaxillofacial surgeons involved in orbital surgery in general and in the treatment of midface fractures, eyelid surgery, and orthognathic procedures in particular should be aware of the possibility of the TCR and should be familiar with its prevention and therapy.

The trigemino-cardiac reflex: an update of the current knowledge

The trigemino-cardiac reflex (TCR) is clinically defined as the sudden onset of parasympathetic activity, sympathetic hypotension, apnea, or gastric hypermotility during central or peripheral stimulation of any of the sensory branches of the trigeminal nerve. Clinically, the TCR has been reported to occur during craniofacial surgery, manipulation of the trigeminal nerve/ganglion and during surgery for lesion in the cerebellopontine angle, cavernous sinus, and the pituitary fossa. Apart from the few clinical reports, the physiologic function of this brainstem reflex has not yet been fully explored. The manifestation of the TCR can vary from bradycardia and hypotension to asystole. From the experimental findings, the TCR represents an expression of a central reflex leading to rapid cerebrovascular vasodilatation generated from excitation of oxygen-sensitive neurons in the rostral ventro-lateral medulla oblongata. By this physiologic response, the systemic and cerebral circulations may be adjusted in a way that augments cerebral perfusion. This review summarizes the current state of knowledge about TCR.

Oculocardiac reflex induced by zygomatic arch fracture in a crossbreed dog

A 3-year-old crossbreed male dog was presented with a history of blunt facial trauma. Skull radiographs showed right zygomatic arch fracture. An electrocardiogram revealed bradycardia, first-degree atrioventricular block and QT prolongation. Standard biochemical profile including electrolytes was normal. Atropine response test (0.04 mg/kg intravenously) restored normal sinus rhythm at a rate of 140 bpm with normal QT and PR intervals. This observation is consistent with oculocardiac reflex secondary to zygomatic arch fracture.

Trigemino-cardiac reflex: the trigeminal depressor responses during skull base surgery

OBJECTIVE

To observe and analyze the occurrence and management of the trigemino-cardiac reflex (TCR) defined as the phenomenon of abrupt drops in heart rate (HR) and blood pressure during skull base surgery.

METHOD

One hundred patients underwent skull base surgery for various lesions were recruited and great attention was paid to heart rate and blood pressure throughout the surgical procedure to screen intraoperative TCR.

RESULT

Twelve patients had TCR intro-operatively, all patients showed abrupt drops in HR of 38% from a mean of 78 beats/min to a mean of 49 beats/min, mean arterial blood pressure (MABP) decreased 33% from a mean of 93 mmHg to a mean of 60 mmHg, respectively. TCR was resolved spontaneously in eight patients, but had to be offset by intraoperative administration of relatively higher dose atropine in another four patients.

CONCLUSION

(1) Manipulation at or near the trigeminal nerve during the skull base surgery may cause TCR, even if premedication with anticholinergic drug is used; (2) cessation of irritation from surgical manipulation to disrupt the reflex is the most important step to offset TCR; (3) continuous, especially repeated TCR in some rare cases occasionally necessitates the administration of high dose atropine.

Trigemino-cardiac reflex during transsphenoidal surgery for pituitary adenomas: Methodological description of a prospective skull base study protocol

A systematic clinical neuroscience protocol is described for the use to examine the trigemino-cardiac reflex (TCR) response in humans. Target neurosurgical conditions are operations that require manipulations around the peripheral and central part of the trigeminal nerve and its branches, e.g. the cerebellopontine angle or the sellar region. To assess the hemodynamic and cardiac responses of patients after TCR initiation, anesthetic monitoring has been applied. The TCR is defined as a drop of more than 20% of the heart rate and the mean arterial blood pressure compared with the baseline values before the stimulus and coinciding with the surgical manipulation at or around any branches of the trigeminal nerve. By help of illustrative cases, we present for the first time preliminary results regarding the differentiation of the TCR in a central and a peripheral induction during transsphenoidal surgery of pituitary adenomas. Based on these results, we can conclude that we have developed a battery of preoperative examination procedures based on event-related diagnostics that was useful to differentiate different subgroups of TCR during transsphenoidal surgery. The presented protocol can be performed directly pre-, intra- and postoperatively and applied for assessment of TCR even in patients with known risk factors.

The impact of hypotension due to the trigeminocardiac reflex on auditory function in vestibular schwannoma surgery

Object

Surgical manipulation of the fifth cranial nerve during its intra- or extracranial course may lead to bradycardia or even asystole as well as arterial hypotension, a phenomenon described as the trigeminocardiac reflex (TCR). The authors studied the impact of this reflex on postoperative auditory function in patients undergoing vestibular schwannoma (VS) surgery.

Methods

One hundred patients scheduled for VS surgery were studied prospectively for parameters influencing the postoperative auditory function. The evaluation included sex, age, pre- and postoperative auditory function, preoperative mean arterial blood pressure, preoperative medical diseases or medication (for example, antiarrhythmia drugs), tumor size and localization, and the intraoperative occurrence of the TCR.

The TCR, which occurred in 11% of the patients, influenced the postoperative hearing function in the patients with Hannover Class T3 and T4 VSs.

With an overall hearing preservation of 47%, 11.1% of the patients in the TCR group and 51.4% of those in the non-TCR group experienced preserved hearing function postoperatively. In cases involving larger tumors (Hannover Class T3 and T4), an intraoperative TCR was associated with a significantly worse postoperative hearing function during VS surgery (p = 0.005).

Conclusions

The hypotension following TCR is a negative prognostic factor for hearing preservation in patients undergoing VS surgery. Patients’ knowledge of this can be increased pre- and postoperatively. Further study of this phenomenon will advance the understanding of the underlying mechanisms and may help to improve hearing preservation by controlling the occurrence of the TCR.

Trigemino-cardiac reflex during transsphenoidal surgery for pituitary adenomas

BACKGROUND

The trigemino-cardiac reflex (TCR) is a well-recognized phenomenon consisting of bradycardia, arterial hypotension, apnea, and gastric hypermotility. It occurs during ocular surgery or other manipulations around the orbit and can also be elicited by stimulation of the central part of the trigeminal nerve during surgery for processes of the cerebellopontine angle. The present retrospective study was conducted to determine if TCR occurs during transsphenoidal surgery in the same way.

METHODS

TCR was defined as a drop in mean arterial blood pressure (MABP) and the heart rate (HR) of more than 20% to the baseline values before the stimulus and coinciding with manipulation of the trigeminal nerve. Pre-, intra-, and postoperative HR and MABP were retrospectively reviewed in 117 patients who underwent resection of pituitary adenomas near the trigeminal nerve at the cavernous sinus in the supine position. Tumor invasiveness was classified according to the modified Hardy criteria.

RESULTS

Of the 117 patients with immunohistochemically and/or electromicroscopically proven pituitary adenoma, 12 (10%) patients demonstrated intraoperative evidence of TCR according to the strict inclusion criteria. In these 12 patients, the HR and MABP decreased by a mean of 43 and 54%, respectively, from the preoperative mean levels during microsurgical manipulation near the cavernous sinus and returned to physiological levels within 10 min after cessation of this surgical maneuver. The percentage of invasive adenomas (grade III-IV) was significantly higher in the TCR subgroup than in the non-TCR subgroup (83% versus 22%).

CONCLUSION

The present results give evidence for the first time that TCR may occur during transsphenoidal surgery in the supine position for resection of pituitary adenomas near the cavernous sinus, leading to a significant decrease in HR and MABP under a standardized anesthetic protocol.

The falcine trigeminocardiac reflex: case report and review of the literature

BACKGROUND

Trigeminocardiac reflex (TCR), the reproducible hypotension and bradycardia upon stimulation of the trigeminal nerve, has been reported during craniofacial surgery and during surgery within the cerebellopontine angle, petrosal sinus, orbit, and trigeminal ganglion. Whereas the falx cerebri is known to be innervated by the nervus tentorii, a recurrent branch of V1, there have been no reports to date of this response upon mechanical stimulation of the falx.

CASE DESCRIPTION

We report a case of immediate, reproducible, and reflexive response of asystole upon stimulation of the falx cerebri during operative resection of a parafalcine meningioma in a 53-year-old woman. Upon recognition of the reproducible relationship between falcine stimulation and increased vagal tone, the patient was given glycopyrrolate in an effort to block cholinergic hyperactivity. After glycopyrrolate was given, no further dysrhythmias occurred.

CONCLUSION

In this patient, mechanical stimulation of the falx likely resulted in the hyperactivity of the trigeminal ganglion, thereby triggering TCR. The dorsal region of the spinal trigeminal tract includes neurons from hypoglossal and vagus nerves, and projections have been seen between the vagus and trigeminal nuclei. The vagus provides parasympathetic innervation to the heart, vascular smooth muscle, and abdominal viscera. Vagal stimulation via these connections after trigeminal nerve activation likely accounts for the reflexive response of asystole seen in this patient. This is confirmed by the observation that the reflex was inhibited by the anticholinergic effects of glycopyrrolate. Awareness of TCR allows for early detection and appropriate treatment.

Trigeminocardiac reflex: a unique case of recurrent asystole during bilateral trigeminal sensory root rhizotomy

BACKGROUND

The trigeminocardiac reflex is the sudden-onset of dysrhythmia and hypotension during manipulation of any of the branches of the trigeminal nerve. The trigeminal nerve and cardioinhibitory vagus nerve constitute the afferent and efferent pathways in the reflex arc. The trigeminocardiac reflex has been reported to occur during craniofacial surgery, balloon-compression rhizolysis of the trigeminal ganglion, and tumour resection in the cerebellopontine angle.

PATIENT & METHOD

A 2-year-old male patient with haemangioma near the sella turcica underwent rhizotomies of both sides of the dorsal sensory roots, of the trigeminal nerves for palliation of intractable trigeminal pain.

RESULTS

In this report, we experienced two unexpected episodes of asystole after transection of the sensory roots of the trigeminal nerves.

CONCLUSION

Sectioning of the intracranial dorsal sensory root of the trigeminal nerve provides clear evidence of the central role of the trigeminal nerve as the afferent pathway of the trigeminocardiac reflex arc.

Trigeminocardiac reflex during surgery in the cerebellopontine angle

OBJECT

In different experimental studies authors have analyzed the autonomic responses elicited by the electrical, mechanical, or chemical stimulation of the trigeminal nerve system. The trigeminocardiac reflex (TCR) is a well-recognized phenomenon that consists of bradycardia, arterial hypotension, apnea, and gastric hypermotility. It occurs during ocular surgery and during other manipulations in and around the orbit. Thus far, it has not been shown that central stimulation of the trigeminal nerve can also cause this reflex.

METHODS

The TCR was defined as clinical hypotension with a drop in mean arterial blood pressure (MABP) of more than 20% and bradycardia lower than 60 beats/minute. Pre-, intra-, and postoperative heart rate (HR) and MABP were reviewed retrospectively in 125 patients who underwent surgery for tumors of the cerebellopontine angle (CPA), and they were divided into two groups on the basis of the occurrence of the TCR during surgery. Of the 125 patients, 14 (11%) showed evidence of the TCR during dissection of the tumor near the trigeminal nerve at the brainstem. Their HRs fell 38% and their MABPs fell 48% during operative procedures as compared with preoperative levels. After cessation of manipulation, the HRs and the MABPs returned to preoperative levels. Risk factors for the occurrence of the TCR were compared with results from the literature.

CONCLUSIONS

The authors' results show the possibility of occurrence of a TCR during manipulation of the central part of the trigeminal nerve when performing surgery in the CPA.

Is there a cholinergic and an adrenergic phase of the oculocardiac reflex during strabismus surgery?

We investigated the counterregulatory effect of the oculocardiac reflex (OCR) in 25 infants and children during strabismus surgery under three experimental conditions. In group 1, a series of measurements were recorded when the OCR was elicited by traction. The beat-to-beat heart rate reduction ranged from -26 to -64 beats/min (median: -46 beats/min). Constant traction increased heart rate in all patients from +23 to +50 beats/min (median: +30.5; P < 0.001). After a sudden release of the stimulation, heart rate rose further from +6 to +40 beats/min (median: +15; P < 0.001). In group 2, atropine (0.01 mg/kg) was administered 3-4 min prior to the same manipulations as in group 1. Constant traction changed heart rate from -1 to +20 beats/min (median: +4.5; P < 0.01). In group 3, a retrobulbar blockade suppressed the OCR and the counterregulation completely. These findings indicate that there is an active counterregulatory process which maintains heart rate during traction at the extraocular muscles after the bradycardic reflex has been initiated. The bradycardia and the counterregulation may be referred to as cholinergic and adrenergic phrases of the OCR. Atropine eliminates the cholinergic phase. Our study indicates that there may be receptors and afferent fibres for both phases, which can be blocked by local anaesthetics.

Bradycardia after orbital injury. Case report

A case of severe bradycardia following orbital trauma is described. This complication caused by the oculocardiac reflex deserves attention when patients are referred for orbital trauma.

Trigeminocardiac reflexes: maxillary and mandibular variants of the oculocardiac reflex

Three case reports are presented to illustrate the existence and importance of reflex bradycardic responses that can occur during maxillofacial surgical procedures. All three patients were healthy young adults undergoing operations which did not include any manipulation of orbital structures. After the patients had been anaesthetized for some time and were haemodynamically stable, profound bradycardia or ventricular asystole occurred suddenly in response to manipulations of the bony structures of the maxilla or mandible, or dissection of, or traction on, the attached soft tissue structures. The parasympathetic supply to the face is carried in the trigeminal nerve. Alternative afferent pathways must exist via the maxillary and/or mandibular divisions, in addition to the commonly reported pathway via the ophthalmic division of the trigeminal nerve in the classic oculocardiac reflex. The efferent arc involves the vagus, regardless of which branch of the trigeminal nerve transmits the afferent impulses. All patients undergoing maxillofacial procedures should be monitored carefully for reflex bradycardia and ventricular asystole.

Reflex bradycardia during TMJ arthroscopy: case report

A case of bradycardia occurring during TMJ arthroscopy is presented. A similar case of the TVR has not previously been reported. This reflex must be recognized by oral and maxillofacial surgeons who perform arthroscopy.

Sinus bradycardia related to temporomandibular joint surgery

The carotid artery lies in close relationship to the temporomandibular joint (TMJ). Manipulation of the mandible during TMJ surgery has been observed in several cases to be directly associated with the development of sinus bradycardia as the joint is distracted during arthrotomy and arthroplasty procedures. We report several cases and discuss differential diagnosis of sinus bradycardia associated with positional changes of the TMJ. This report emphasizes the importance to the surgeon and to the anesthesiologist of recognition of this cardiac phenomenon, mediated through the trigeminovagal reflex, to appropriately manage the patients during TMJ surgery.

Bradycardia and the trigeminal nerve

A review of the literature suggests that the oculocardiac reflex is part of a wider phenomenon involving any structure supplied by the trigeminal nerve. This can lead to potentially fatal complications in maxillofacial surgery. A review of the literature is discussed and two further cases are reported.

A technique for reducing fractures of the zygomatic complex under local anaesthesia

Fractures of the zygomatic complex are common. A technique is described which enables the majority of these fractures to be reduced under local anaesthetic, intravenous sedation and analgesia on an out-patient basis. The benefits to the patient and to the hospital are highlighted.

Asystole during Le Fort I osteotomy

A case report of asystole occurring during down-fracture of a maxilla in a Le Fort I osteotomy procedure is described. The case serves to illustrate an extreme example of the trigeminovagal reflex during manipulation of the maxilla.