ABSTRACT; The trigeminocardiac reflex (TCR) is a brainstem reflex describing the acute hemodynamic perturbations in neurosurgical patients. The roles of different anatomic locations of this reflex arc on end responses have been found to be variable. In this article, we have highlighted the role and importance of different TCR pathway (peripheral vs central) mechanisms, their manifestations and the various risk factors associated with these. In addition, new insights into various other non-neurosurgical conditions, in special relation to neurointerventional procedures, are also presented in this article. This study is a narrative review based on a PubMed/Google search (from 1 January 1970 to 31 March 2013) on this topic. The common manifestations, such as hypotension and bradycardia, are vagal-dominated responses; however, unusual manifestations, such as hypertension and tachycardia, signify the involvement of the sympathetic nervous system. In addition, there is a complex interaction of the various sensory receptors at the Gasserian ganglion, and this is responsible for the different presentations. There are many surgical as well as nonsurgical risk factors associated with TCR. Interestingly, TCR may affect functional outcome and has been found to be involved in some normal physiological mechanisms, including bruxism. TCR is a complex neurophysiological reflex and there are variable presentations depending upon the peripheral or central stimulation surrounding the Gasserian ganglion. We suggest, for the first time, that if the TCR is initiated at the Gasserian ganglion, it reacts in a different manner from the better-known central or peripheral TCR.

The perioperative management of post-craniotomy pain is controversial. Although the concept of pain control in non-neurosurgical fields has grown substantially, the understanding of neurosurgical pain and its causative factors in such a population is inconclusive. In fact, the organ that is the center of pain and its related mechanisms receives little attention to alleviate distress during neurosurgical procedures. In contrast to the old belief that pain following intracranial surgery is minimal, recent data suggest the exact opposite. Despite the evolution of various multimodal analgesic techniques for optimal pain control, the concern of post-craniotomy pain remains. This paradox could be due to the lack of thorough understanding of different perioperative factors that can influence the incidence and intensity of pain in post-craniotomy population. Therefore, this review aims to give an in-depth insight into the various aspects of pain and its related factors in adult neurosurgical patients.

Perioperative safety concerns are a major area of interest in recent years. Severe cardiac perturbation such as cardiac arrest is one of the most dreaded complications in the intraoperative period; however, little is known about the management of these events in the patients undergoing elective neurosurgery. This special group needs further attention, as it is often neither feasible nor appropriate to apply conventional advanced cardiac life support algorithms in patients undergoing neurosurgery. Factors such as neurosurgical procedure and positioning can also have a significant effect on the occurrence of cardiac arrest. Therefore, the aim of this paper is to describe the various causes and management of cardiac emergencies with special reference to cardiac arrest during elective neurosurgical procedures, including discussion of position-related factors and resuscitative considerations in these situations. This will help to formulate possible guidelines for management of such events.

Purpose The complexity of neurosurgical procedures and their interactions with maternal and fetal physiologies are key factors in determining the overall maternal and fetal outcome. The literature and guidelines provide only partial information regarding the standard of care in these cases. The purpose of this Continuing Professional Development module is to review the issues related to common neurosurgical conditions and their optimal anesthetic management. Principal findings The most common neurosurgical conditions found in pregnancy include brain tumours, cerebrovascular diseases, spinal pathologies, and neurotrauma. Though rare, these conditions and related procedures may affect maternal and fetal outcome. Maternal considerations should be given priority in cases of emergent surgeries irrespective of trimester. In the early first trimester, risk of fetal loss and congenital malformation are substantial; hence, proper counselling should be given to the mother with special emphasis on therapeutic abortion. When indicated, anticonvulsants should be started as early as possible and continued throughout pregnancy. Surgical procedures can be performed with relative safety during the second trimester and early third trimester. After 34 weeks, delivery seems to be the first choice, and the role of regional anesthesia in this situation should be carefully planned after proper review of neurosurgical pathology and maternal condition. During acute neurological deterioration, however, Cesarean delivery under general anesthesia should be anticipated. Conclusion A multidisciplinary approach with good communication amongst all team members certainly plays a crucial role for successful management of such cases.

Background. Coronary artery spasm (CAS) is a rarely reported complication in neurosurgical patients and its main causative mechanism was attributed to vagal mediated responses. However, these may be the unusual manifestations of trigeminal cardiac reflex (TCR) which is a well established brain stem reflex observed in various neurosurgical patients. Methods and Results. In this review, we have searched for the case reports/papers related to intraoperative coronary spasm in neurosurgical patients and described the role of TCR in this regard. TCR is a possible mechanism in producing CAS in most of the cases in which stimulation occurred at or near the vicinity of trigeminal nerve. It is likely that TCR mediated coronary spasm may be a physiological mechanism and not related to actual myocardial insult apparent by cardiac enzymes or echocardiography studies in most of the cases. Some common risk factors may also exist related to occurrence of CAS as well as TCR. Conclusions. In conclusion, neurosurgical procedures occurring at the vicinity of trigeminal nerve may produce CAS even in previously healthy patients and may produce catastrophic consequences. There is a need for future reports and experimental studies on the interaction of TCR and pathophysiological mechanisms related to CAS.