Awake Craniotomy Under 3-Tesla Intraoperative Magnetic Resonance Imaging: A Retrospective Descriptive Report and Canadian Institutional Experience.

BACKGROUND: The role of high-field 3-Tesla intraoperative magnetic resonance imaging (I-MRI) during awake craniotomy (AC) has not been extensively studied. We report the feasibility and safety of AC during 3-Tesla I-MRI. METHODS: This retrospective descriptive report compared 3 groups: AC with minimal sedation and I-MRI; I-MRI-guided craniotomy under general anesthesia (GA), and; AC without I-MRI. Perioperative factors, surgical, anesthetic and radiologic complications, and postoperative morbidity and mortality were recorded. RESULTS: Overall, 85 patients are included in this report. Five of 23 patients (22%) who underwent AC with I-MRI had anesthetic complications (nausea/vomiting and conversion to GA) compared with 3 of 40 (8%) who underwent I-MRI-guided craniotomy under GA (nausea/vomiting during extubation, and arrhythmia). Intraoperative surgical complications (seizures and speech deficits) occurred in 5 patients (22%) who underwent AC and I-MRI, excessive intraoperative bleeding occurred in 2 patients (5%) who had I-MRI-guided craniotomy under GA, and 4 of 22 (18%) patients who underwent AC without I-MRI experienced neurological complications (seizures, motor deficits, and transient loss of consciousness). Eight patients (20%) who had I-MRI with GA had postoperative complications, largely neurological. The duration of surgery and anesthesia were shortest in the group of patients receiving AC without I-MRI. Seventy-three percent of the patients in this group had residual tumor postoperatively compared with 44% and 38% in those having I-MRI with AC or GA, respectively. Patients who underwent I-MRI-guided craniotomy with GA had the highest morbidity (8%) at hospital discharge. CONCLUSIONS: Our institutional experience suggests that AC under 3-Tesla I-MRI could be an option for glioma resection, although firm conclusions cannot be drawn given the limited and heterogenous nature of our data. Future multicenter trials comparing anesthetic and imaging modalities for glioma resection are recommended.

Role of topical magnesium in post-operative sore throat: A systematic review and meta-analysis of randomised controlled trials.

BACKGROUND AND AIMS: Post-operative sore throat (POST) is a common undesirable consequence of tracheal intubation. Magnesium, an N-methyl-D-aspartate receptor antagonist, has anti-nociceptive and anti-inflammatory properties, and has been found to be useful in POST prevention in various trials. We conducted this systematic review and meta-analysis to study the efficacy of topical magnesium in preventing POST in adult patients undergoing surgery under general anaesthesia with single lumen tracheal tube. METHODS: Comprehensive literature search was performed in PubMed, Google Scholar, EMBASE, Scopus and the Cochrane central registers of controlled trial databases through July, 2018 and data were pooled using fixed effect modelling followed by random-effect methods (after assessing heterogeneity with fixed modelling). The primary outcome was the incidence of POST at 24 h after surgery/extubation. Comparative results were deliberated as pooled mean difference for continuous variables and Mantel-Haenszel (MH) odds ratio for dichotomous variables. Statistical analysis was done using Comprehensive Meta-Analysis-Version 3 (Biostat Inc., USA). RESULTS: Seven trials involving 726 study participants were included in the final analysis. Incidence of POST at 24 hours was significantly lower in magnesium group (26/363) in comparison to active and non-active control group (89/363); P = 0.00- RR 0.22 (95%CI = 0.12-0.39, I2 = 0%). No significant adverse events were reported with the use of topical magnesium. CONCLUSION: Prophylactic use of topical magnesium before the induction of general anaesthesia seems to be an effective measure to decrease the incidence of POST.

The Role of Intraoperative MRI in Awake Neurosurgical Procedures: A Systematic Review.

Background: Awake craniotomy for brain tumors remains an important tool in the arsenal of the treating neurosurgeon working in eloquent areas of the brain. Furthermore, with the implementation of intraoperative magnetic resonance imaging (I-MRI), one can afford the luxury of imaging to assess surgical resection of the underlying gross imaging defined neuropathology and the surrounding eloquent areas. Ideally, the combination of I-MRI and awake craniotomy could provide the maximal lesion resection with the least morbidity and mortality. However, more resection with the aid of real time imaging and awake craniotomy techniques might give opposite outcome results. The goal of this systematic review.is to identify the available literature on combined I-MRI and awake craniotomy techniques, to better understand the potential morbidity and mortality associated. Methods: MEDLINE, EMBASE, and CENTRAL were searched from inception up to December 2016. A total of 10 articles met inclusion in to the review, with a total of 324 adult patients. Results: All studies showed transient neurological deficits between 2.9 to 76.4%. In regards to persistent morbidity, the mean was ~10% (ranges from zero to 35.3%) with a follow up period between 5 days and 6 months. Conclusion: The preliminary results of this review also suggest this combined technique may impose acceptable post-operative complication profiles and morbidity. However, this is based on low quality evidence, and is therefore questionable. Further, well-designed future trials with the long-term follow-up are needed to provide various aspects of feasibility and outcome data for this approach.

Hemodynamic Perturbations in Deep Brain Stimulation Surgery: First Detailed Description.

Background: Hemodynamic perturbations can be anticipated in deep brain stimulation (DBS) surgery and may be attributed to multiple factors. Acute changes in hemodynamics may produce rare but severe complications such as intracranial bleeding, transient ischemic stroke and myocardium infarction. Therefore, this retrospective study attempts to determine the incidence of hemodynamic perturbances (rate) and related risk factors in patients undergoing DBS surgery. Materials and Methods: After institutional approval, all patients undergoing DBS surgery for the past 10 years were recruited for this study. Demographic characteristics, procedural characteristics and intraoperative hemodynamic changes were noted. Event rate was calculated and the effect of all the variables on hemodynamic perturbations was analyzed by regression model. Results: Total hemodynamic adverse events during DBS surgery was 10.8 (0-42) and treated in 57% of cases. Conclusion: Among all the perioperative variables, the baseline blood pressure including systolic, diastolic, and mean arterial pressure was found to have highly significant effect on these intraoperative hemodynamic perturbations.

Perioperative Factors Contributing the Post-Craniotomy Pain: A Synthesis of Concepts.

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.

The Role of Simulation in Planning Intraoperative Magnetic Resonance Imaging-Guided Neurosurgical Procedures: A Case Report.

Simulation of the actual procedure is a simple and yet effective method of increasing patient safety and reducing the rate of unexpected adverse effects. We present our experience with 2 cases of preprocedural simulation on healthy volunteers that were performed in the intraoperative magnetic resonance imaging suite. During one of the cases, we also simulated a scenario of sudden cardiac arrest. Such an approach helped us to refine the procedures and coordinate the work of different teams within the intraoperative magnetic resonance imaging suite as well as improve the quality of patient management.

Cardiac emergencies in 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.

Anaesthesia in underdeveloped world: Present scenario and future challenges.

The overall mortality and morbidity in underdeveloped countries are still unchanged and preventable risks factors constitute the main burden. Among these, anaesthesia-related mortality is largely preventable. Various contributory factors related to human resources, technical resources, education/teaching system and other utilities needs further attention in poor income group countries. Therefore, we have made an attempt to address all these issues in this educational article and have given special reference to those factors that might gain importance in (near) future. Proper understanding of anaesthesia-related resources, their overall impact on health care system and their improvisation methods should be thoroughly evaluated for providing safer anaesthesia care in these countries which would certainly direct better outcome and consequently influence mortality.

Controversies in the anesthetic management of intraoperative rupture of intracranial aneurysm.

Despite great advancements in the management of aneurysmal subarachnoid hemorrhage (SAH), outcomes following SAH rupture have remained relatively unchanged. In addition, little data exists to guide the anesthetic management of intraoperative aneurysm rupture (IAR), though intraoperative management may have a significant effect on overall neurological outcomes. This review highlights the various controversies related to different anesthetic management related to aneurysm rupture. The first controversy relates to management of preexisting factors that affect risk of IAR. The second controversy relates to diagnostic techniques, particularly neurophysiological monitoring. The third controversy pertains to hemodynamic goals. The neuroprotective effects of various factors, including hypothermia, various anesthetic/pharmacologic agents, and burst suppression, remain poorly understood and have yet to be further elucidated. Different management strategies for IAR during aneurysmal clipping versus coiling also need further attention.

Coronary spasm in neurosurgical patients and role of trigeminocardiac reflex.

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.

Perioperative variables contributing to the rupture of intracranial aneurysm: an update.

BACKGROUND: Perioperative aneurysm rupture (PAR) is one of the most dreaded complications of intracranial aneurysms, and approximately 80% of nontraumatic SAHs are related to such PAR aneurysms. The literature is currently scant and even controversial regarding the issues of various contributory factors on different phases of perioperative period. Thus this paper highlights the current understanding of various risk factors, variables, and outcomes in relation to PAR and try to summarize the current knowledge. METHOD: We have performed a PubMed search (1 January 1991-31 December 2012) using search terms including "cerebral aneurysm," "intracranial aneurysm," and "intraoperative/perioperative rupture." RESULTS: Various risk factors are summarized in relation to different phases of perioperative period and their relationship with outcome is also highlighted. There exist many well-known preoperative variables which are responsible for the highest percentage of PAR. The role of other variables in the intraoperative/postoperative period is not well known; however, these factors may have important contributory roles in aneurysm rupture. Preoperative variables mainly include natural course (age, gender, and familial history) as well as the pathophysiological factors (size, type, location, comorbidities, and procedure). Previously ruptured aneurysm is associated with rupture in all the phases of perioperative period. On the other hand intraoperative/postoperative variables usually depend upon anesthesia and surgery related factors. Intraoperative rupture during predissection phase is associated with poor outcome while intraoperative rupture at any step during embolization procedure imposes poor outcome. CONCLUSION: We have tried to create such an initial categorization but know that we cannot scale according to its clinical importance. Thorough understanding of various risk factors and other variables associated with PAR will assist in better clinical management as well as patient care in this group and will give insight into the development and prevention of such a catastrophic complication in these patients.

Perioperative considerations for neurosurgical procedures in the gravid patient: Continuing Professional Development.

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.

Role of colloids in traumatic brain injury: Use or not to be used?

Trauma is a leading cause of death worldwide and traumatic brain injury is one of the commonest injuries associated with it. The need for urgent resuscitation is warranted for prevention of secondary insult to brain. However, the choice of fluid in such cases is still a matter of conflict. The literature does not provide enough data pertaining to role of colloids in head injury patients. In this article, we have tried to explore the present role of colloid resuscitation in patient with head injury.

Early brain injury and subarachnoid hemorrhage: Where are we at present?

The current era has adopted many new innovations in nearly every aspect of management of subarachnoid hemorrhage (SAH); however, the neurological outcome has still not changed significantly. These major therapeutic advances mainly addressed the two most important sequels of the SAH-vasospasm and re-bleed. Thus, there is a possibility of some different pathophysiological mechanism that would be responsible for causing poor outcome in these patients. In this article, we have tried to compile the current role of this different yet potentially treatable pathophysiological mechanism in post-SAH patients. The main pathophysiological mechanism for the development of early brain injury (EBI) is the apoptotic pathways. The macro-mechanism includes increased intracranial pressure, disruption of the blood-brain barrier, and finally global ischemia. Most of the treatment strategies are still in the experimental phase. Although the role of EBI following SAH is now well established, the treatment modalities for human patients are yet to be testified.