Awake craniotomy: A qualitative review and future challenges

Awake neurosurgery: Advancements in microvascular decompression for trigeminal neuralgia

Background

The treatment landscape for trigeminal neuralgia (TN) involves various surgical interventions, among which microvascular decompression (MVD) stands out as highly effective. While MVD offers significant benefits, its success relies on precise surgical techniques and patient selection. In addition, the emergence of awake surgery techniques presents new opportunities to improve outcomes and minimize complications associated with MVD for TN.

Methods

A thorough review of the literature was conducted to explore the effectiveness and challenges of MVD for TN, as well as the impact of awake surgery on its outcomes. PubMed and Medline databases were searched from inception to March 2024 using specific keywords "Awake Neurosurgery," "Microvascular Decompression," AND "Trigeminal Neuralgia." Studies reporting original research on human subjects or preclinical investigations were included in the study.

Results

This review highlighted that MVD emerges as a highly effective treatment for TN, offering long-term pain relief with relatively low rates of recurrence and complications. Awake surgery techniques, including awake craniotomy, have revolutionized the approach to MVD, providing benefits such as reduced postoperative monitoring, shorter hospital stays, and improved neurological outcomes. Furthermore, awake MVD procedures offer opportunities for precise mapping and preservation of critical brain functions, enhancing surgical precision and patient outcomes.

Conclusion

The integration of awake surgery techniques, particularly awake MVD, represents a significant advancement in the treatment of TN. Future research should focus on refining awake surgery techniques and exploring new approaches to optimize outcomes in MVD for TN.

High-Volume Centers Provide Superior Value of Care in the Surgical Treatment of Malignant Brain Tumor

BACKGROUND

Improved outcomes in surgical patients have been associated with increasing volume of cases. This has led to the development of centers that facilitate care for a specific patient population. This study aimed to evaluate associations of outcomes with hospital characteristics in patients undergoing resection of malignant brain tumors.

METHODS

The 2016-2020 National Inpatient Sample was queried for patients undergoing resection of malignant brain tumors. Teaching hospitals with caseloads >2 standard deviations above the mean (140 cases) were categorized as high-volume centers (HVCs). Value of care was evaluated by adding one point for each of the following: short length of stay, low total charges, favorable discharge disposition, and lack of major comorbidity or complication.

RESULTS

In 3009 hospitals, 118,390 patients underwent resection of malignant brain tumors. HVC criteria were met by 91 (3%) hospitals. HVCs were more likely to treat patients of younger age or higher socioeconomic status (P < 0.01 for all). The Mid-Atlantic and South Atlantic regions had the highest percentage of cases and number of HVCs. Value of care was higher at HVCs (P < 0.01). Care at HVCs was associated with decreased complications (P < 0.01 for all) and improved patient outcomes (P < 0.01 for all).

CONCLUSIONS

Patients undergoing craniotomy for malignant brain neoplasms have superior outcomes in HVCs. Trends of centralization may reflect the benefits of multidisciplinary treatment, geographic preferences, publicity, and cultural impact. Improvement of access to care is an important consideration as this trend continues.

Anaesthetic considerations and challenges during awake craniotomy

ABSTRACT

This article summarises the key anaesthetic considerations and challenges surrounding the perioperative management of a patient undergoing awake craniotomy. The main goals include patient comfort, facilitation of patient cooperation during the critical awake phase and maintenance of optimal operating conditions. These are achieved through appropriate patient selection and preparation, familiarity with the complexity of each surgical phase and potential complications that may arise, as well as maintenance of close communication among all team members. Challenges such as loss of patient cooperation, loss of airway, intraoperative nausea and vomiting, seizures, cerebral oedema, hypertension, blood loss and use of intraoperative magnetic resonance imaging are discussed. The importance of teamwork, competence, vigilance and clear management strategies for potential complications to maximise patient outcomes is also highlighted.

Awake Craniotomy Surgery in Pediatrics: A Systematic Review

BACKGROUND

Awake craniotomy is a unique method to prevent motor deficits during the resection of lesions located in or close to functional areas. We sought to study the outcomes of pediatric craniotomy on published studies.

METHODS

The search for articles was performed through multiple search engines: PubMed, Google Scholar, Web of Science, and Wiley. The following search terms were used for screening the titles and abstracts: "awake brain surgery" and "children" or "pediatrics," "awake craniotomy," and "children" or "pediatrics," "pediatrics awake craniotomy," "awake brain surgery pediatrics," and "tumors." On initial screening of the titles and abstracts, 54 articles were found. After a thorough review of the full texts of obtained articles and removing duplicates, 16 articles remained.

RESULTS

The mean age group was 12.23 years. There was a slight difference between genders who underwent awake craniotomy in the pediatric age group, 52.7% male and 47.3% for female. Tumor resection was the most common indication of the surgery. Almost half (47.9%) experienced complete recovery following the surgery. However, of those who had complicated recovery, 7.5% experienced a speech deficit.

CONCLUSIONS

This systematic review summarized that awake brain surgery can prevent significant motor and language deficits postoperatively in children after tumor resection as it is considered a feasible and safe procedure.

The current state of the art of primary motor mapping for tumor resection: A focused survey

INTRODUCTION

Cortical and subcortical motor mapping has advanced the notion of maximal safe resection of intra-axial brain tumours, thereby preserving neurological functions as well as improving survival. Despite being an age-old and established neurosurgical procedure across the world, the strategy and techniques involved in motor mapping have a gamut of variation due to a lack of defined standard protocols.

METHODS

We disseminated a structured survey among focused group of neurosurgeons with established practices involving brain mapping. It consisted of 40 questions, split into five sections assessing the practice description, general approach for motor mapping, preference for asleep versus awake mapping, operative techniques and approach to representative tumor cases. Practice-patterns during primary motor mapping for brain tumours were analysed from responses of 51 neurosurgeons.

RESULTS

60.8 % felt that any lesion even near (without infiltration) was suffice to define "involvement" of the cortical/subcortical motor pathways. 82.4 % felt that motor mapping was necessary for brain tumours involving motor pathways, irrespective of the tumor histology or patient age. 90.2 % opined that tumor location was the predominant factor affecting their choice between awake or asleep mapping. 31.4 % believed that all cases should be performed awake unless patient-related medical, psychological, or anaesthetic contraindications exist, whereas 45.1 % felt that all cases should be performed asleep unless language mapping is required. MRI, DTI-based tractography and intra-operative fluorescence were the most commonly employed surgical adjuncts.

CONCLUSIONS

The data from this survey may serve as a preliminary foundation for a more standardized approach to patient selection and the approach to motor mapping for brain tumors.

Stress, Anxiety, and Depression Associated With Awake Craniotomy: A Systematic Review

BACKGROUND

Awake craniotomy (AC) enables real-time monitoring of cortical and subcortical functions when lesions are in eloquent brain areas. AC patients are exposed to various preoperative, intraoperative, and postoperative stressors, which might affect their mental health.

OBJECTIVE

To conduct a systematic review to better understand stress, anxiety, and depression in AC patients.

METHODS

PubMed, Scopus, and Web of Science databases were searched from January 1, 2000, to April 20, 2022, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline.

RESULTS

Four hundred forty-seven records were identified that fit our inclusion and exclusion criteria for screening. Overall, 24 articles consisting of 1450 patients from 13 countries were included. Sixteen studies (66.7%) were prospective, whereas 8 articles (33.3%) were retrospective. Studies evaluated stress, anxiety, and depression during different phases of AC. Twenty-two studies (91.7%) were conducted on adults, and 2 studies were on pediatrics (8.3 %). Glioma was the most common AC treatment with 615 patients (42.4%). Awake-awake-awake and asleep-awake-asleep were the most common protocols, each used in 4 studies, respectively (16.7%). Anxiety was the most common psychological outcome evaluated in 19 studies (79.2%). The visual analog scale and self-developed questionnaire by the authors (each n = 5, 20.8%) were the most frequently tools used. Twenty-three studies (95.8%) concluded that AC does not increase stress, anxiety, and/or depression in AC patients. One study (4.2%) identified younger age associated with panic attack.

CONCLUSION

In experienced hands, AC does not cause an increase in stress, anxiety, and depression; however, the psychiatric impact of AC should not be underestimated.

Comparison of Monitored Anesthesia Care with Propofol Versus Dexmedetomidine for Awake Craniotomy: A Retrospective study

Background Anesthetic agents used for awake craniotomy should be safe, short-acting, titratable, and provide an adequate level of sedation and analgesia, along with facilitating adequate neurological assessment during the functional testing. Our study aims to review the efficacy and safety profile, along with the potential for neurophysiological monitoring, of two commonly used anesthetic regimens, i.e., propofol and dexmedetomidine.

Methods After the Ethics Committee approval, a retrospective analysis of 51 patients who underwent awake craniotomy for brain tumor excision over a period of 7 years was done. Those who received monitored anesthesia care (MAC) were divided into two groups, namely, Group P for that received propofol, and Group D that received dexmedetomidine and their hemodynamic profile, perioperative complications, neuromonitoring techniques, and postoperative course was noted from the records.

Results A total of 31 patients were administered MAC with propofol and 20 with dexmedetomidine. The baseline demographic data, duration of surgery, intensive care unit (ICU), and hospital stay were comparable between the two. The hemodynamic profile as assessed by the heart rate and blood pressure was also comparable. The incidence of intraoperative seizures was found to be less in Group P, though. Episodes of transient desaturation were observed more in Group P (9.7%) than in Group D (5%), but none of the patients required conversion to general anesthesia. Direct cortical stimulation was satisfactorily elicited in 80% in Group P and 85% in Group D.

Conclusions MAC with propofol and dexmedetomidine are acceptable techniques with comparable hemodynamic profile, intraoperative and postoperative complications, and potential for neurophysiological monitoring.

Compassion, communication, and the perception of control: a mixed methods study to investigate patients' perspectives on clinical practices for alleviating distress and promoting empowerment during awake craniotomies

PURPOSE

To inquire into clinical practices perceived to mitigate patients' intraoperative distress during awake craniotomies.

METHODS

This mixed-methods study involved administration of Amsterdam Preoperative Anxiety and Information Scale and PTSD Checklist prior to the awake craniotomy to evaluate anxiety and information-seeking related to the procedure and symptoms of PTSD. Generalized Anxiety Disorder Scale and Depression Module of the Patient Health Questionnaire were administered before and after the procedure to evaluate generalized anxiety and depression. Patient interviews were conducted 2-weeks postprocedure and included a novel set of patient experience scales to assess patients' recollection of intraoperative pain, overall distress, anxiety, distress due to noise, perception of empowerment, perception of being well-prepared, overall satisfaction with anaesthesia management, and overall satisfaction with the procedure. Qualitative data were analysed using conventional content analysis.

RESULTS

Participants (n = 14) had undergone an awake craniotomy for tissue resection due to primary brain tumours or medically-refractory focal epilepsy. Validated self-report questionnaires demonstrated reduced levels of generalized anxiety (pre mean = 8.66; SD = 6.41; post mean= 4.36; SD = 4.24) following the awake craniotomy. Postprocedure interviews revealed very high satisfaction with the awake craniotomy and anaesthesia management and minimal levels of intraoperative pain, anxiety, and distress. The most stressful aspects of the procedure included global recognition of medical diagnosis, anxiety provoked by unfamiliar sights, sounds, and sensations, a perception of a lack of information or misinformation, and long periods of immobility. Important factors in alleviating intraoperative distress included the medical team's ability to promote patient perceptions of control, establish compassionate relationships, address unfamiliar intraoperative sensations, and deliver effective anaesthesia management.

CONCLUSION

Compassion, communication, and patient perception of control were critical in mitigating intraoperative distress. Clinical practice recommendations with implications for all clinicians involved in patient care during awake craniotomies are provided. Use of these interventions and strategies to reduce distress are important to holistic patient care and patient experiences of care and may improve the likelihood of optimal brain mapping procedures to improve clinical outcomes during awake craniotomies.

Awake Craniotomy for Resection of Cerebral Arteriovenous Malformation: Initial Experience From a Low- and Middle-Income Country

Global health has shown progress over the years; however, neurosurgical care has not followed the same trajectory due to it being presumably resource intensive. Awake craniotomy (AC) is a neurosurgical technique that can improve neurological outcomes, can potentially reduce costs and hospital stay, and can be easily employed in low- and middle-income countries (LMICs). It has proven to be beneficial in surgical resection of tumors located in the critical areas of the brain, but there is limited literature to support AC for resection of arteriovenous malformations (AVM). We present four cases of AVM that were successfully treated surgically under awake settings in a developing country. Two of the AVMs were Spetzler-Martin grade (SMG) 3, one was SMG 4, and one was SMG 1.

All the patients underwent successful excision of AVMs, and the postoperative digital subtraction angiography (DSA) was negative for any residual. They had a total hospital stay of three to five days with a mean postoperative stay of two days. Only one patient showed transient conductive dysphasia, which resolved on subsequent follow-ups, and none of the patients developed any long-term neurological deficit.

There are limited data from LMICs regarding the benefits of using AC for AVMs. However, our cases show that this technique can be applied for AVM resection, particularly in eloquent areas of the brain (parts of the cerebral cortex that control vision, language, sensory, and motor functions), to minimize potential neurological deficits. Even though it requires careful selection of cases, and needs a higher level of microsurgical and neuro-anesthesia expertise, it can lead to better postoperative outcomes, lesser morbidity, and a shorter hospital stay, contributing to low resource utilization, making it feasible in a resource-limited setting.

Awake craniotomy in brain tumors - Technique systematization and the state of the art

The anesthesia for awake craniotomy (AC) is a consecrated anesthetic technique that has been perfected over the years. Initially used to map epileptic foci, it later became the standard technique for the removal of glial neoplasms in eloquent brain areas. We present an AC anesthesia technique consisting of three primordial times, called awake-asleep-awake, and their respective particularities, as well as delve into the anesthetic medications used. Its use in patients with low and high-grade gliomas was favorable for the resection of tumors within the functional boundaries of patients, with shorter hospital stay and lower direct costs. The present study aims to systematize the technique based on the experience of the largest philanthropic hospital in Latin America and discusses the most relevant aspects that have consolidated this technique as the most appropriate in the surgery of gliomas in eloquent areas.

Role of Extracellular Vesicles in Glioma Progression: Deciphering Cellular Biological Processes to Clinical Applications

Glioma predominantly targets glial cells in the brain and spinal cord. There are grade I, II, III, and IV gliomas with anaplastic astrocytoma and glioblastoma multiforme as the most severe forms of the disease. Current diagnostic methods are limited in their data acquisition and interpretation, markedly affecting treatment modalities, and patient outcomes. Circulating extracellular vesicles (EVs) or "magic bullets" contain bioactive signature molecules such as DNA, RNA, proteins, lipids, and metabolites. These secretory "smart probes" participate in myriad cellular activities, including glioma progression. EVs are released by all cell populations and may serve as novel diagnostic biomarkers and efficient nano-vehicles in the targeted delivery of encapsulated therapeutics. The present review describes the potential of EV-based biomarkers for glioma management.

Awake Epilepsy Surgery in Patients with Focal Cortical Dysplasia

BACKGROUND

Awake craniotomy (AC) and direct electric stimulation emerged together with epilepsy surgery >80 years ago. The goal of our study was to evaluate the benefits of awake surgery in patients with drug-resistant epilepsy caused by focal cortical dysplasia (FCD) affecting eloquent areas.

METHODS

Our material included 95 patients with drug-resistant epilepsy and FCD, who were operated on between January 2009 and December 2018. These 95 patients were assigned into 3 groups: AC; general anesthesia (GA) with intraoperative neuromonitoring; and GA without intraoperative neuromonitoring. We investigated the following variables: age at surgery, lesion side, eloquent cortex involvement, brain mapping success rate, epilepsy surgery success rate, intraoperative complications, postoperative complications, and intraoperative changes of the preoperative resection plan according to results of the brain mapping by direct electric stimulation.

RESULTS

We found statistically significant differences between the AC and GA groups in the mean age at operation, lesion side, eloquent localization, and postoperative transient neurologic deficit. Seizure outcome in the AC was satisfactory (71% complete seizure control) and comparable to the seizure outcome in the GA groups. Our preoperative plan was changed because of functional constraints in 6 patients (43%) operated on during AC.

CONCLUSIONS

AC during epilepsy surgery for FCD in eloquent areas may change the preoperative plan. The good rate of postoperative seizure control and the absence of permanent postoperative neurologic deficit in our series is the main proof that AC is a useful tool in patients with FCD involving the eloquent cortex.

Immersive Virtual Reality and Ocular Tracking for Brain Mapping During Awake Surgery: Prospective Evaluation Study

Background

Language mapping during awake brain surgery is currently a standard procedure. However, mapping is rarely performed for other cognitive functions that are important for social interaction, such as visuospatial cognition and nonverbal language, including facial expressions and eye gaze. The main reason for this omission is the lack of tasks that are fully compatible with the restrictive environment of an operating room and awake brain surgery procedures.

Objective

This study aims to evaluate the feasibility and safety of a virtual reality headset equipped with an eye-tracking device that is able to promote an immersive visuospatial and social virtual reality (VR) experience for patients undergoing awake craniotomy.

Methods

We recruited 15 patients with brain tumors near language and/or motor areas. Language mapping was performed with a naming task, DO 80, presented on a computer tablet and then in 2D and 3D via the VRH. Patients were also immersed in a visuospatial and social VR experience.

Results

None of the patients experienced VR sickness, whereas 2 patients had an intraoperative focal seizure without consequence; there was no reason to attribute these seizures to virtual reality headset use. The patients were able to perform the VR tasks. Eye tracking was functional, enabling the medical team to analyze the patients’ attention and exploration of the visual field of the virtual reality headset directly.

Conclusions

We found that it is possible and safe to immerse the patient in an interactive virtual environment during awake brain surgery, paving the way for new VR-based brain mapping procedures.

Trial Registration

ClinicalTrials.gov NCT03010943; https://clinicaltrials.gov/ct2/show/NCT03010943.

Subjective experience, cognitive functioning and trauma level of patients undergoing awake craniotomy due to brain tumor - Preliminary study

BACKUP AND OBJECTIVE

Awake craniotomy (AC) for brain tumors, when the patient is conscious during the operation, allows to reduce the risk of motor disability and aphasia, however, it may be a source of extreme stress. The aim of our study was to examine the patients' subjective experience of the surgery including the level of psychological trauma and cognitive functioning.

METHOD

Eighteen patients operated due to brain tumor were enrolled in this study. The Essener Trauma-Inventory Questionnaire and the Addenbrooke's Cognitive Examination (ACE III) were administrated. The patients' experience with awake craniotomy was evaluated with a qualitative descriptive survey.

RESULTS

All patients remembered the intraoperative neuropsychological examination and several sensations like: drilling, cold, head clamp fixation or having eyes covered. In most of the patients the postoperative psychological trauma experience did not reach the clinical level. The ACE III postoperative scores revealed partial cognitive deficits with the lowest scores in memory and word fluency domains. Slight amnestic aphasia was observed postoperatively only in two patients.

CONCLUSIONS

Awake craniotomy for resection of brain tumors is well-tolerated by patients and does not cause significant psychological trauma. Nonetheless, anxiety about the procedure warrants further study and individualized neuropsychological care is needed for the emotional preparation of the patient.

Anesthesia management for low-grade glioma awake surgery: a European Low-Grade Glioma Network survey

BACKGROUND

Awake surgery has become a key treatment of diffuse low-grade gliomas (DLGG) and is divided in three main phases: opening, tumor resection - during which the patient needs to be fully awake - and closure. The anesthetic management of awake neurosurgery is a challenge, and there are currently no guidelines.

OBJECTIVE

The objective of the survey was to explore differences and commonalities regarding the anesthetic management of awake DLGG surgery within the European Low-Grade Glioma Network (ELGGN) centers.

METHODS

A form that contained 14 questions about the anesthetic management was sent to 28 centers in May 2015.

RESULTS

Twenty centers responded. During the opening and closing non-awake periods, 56% of teams chose general anesthesia with mechanical ventilation for at least one period (asleep-awake-asleep, SAS protocol), and 44% monitored anesthesia care including sedation without mechanical ventilation (MAC protocol). In case of SAS, all the teams chose intravenous anesthesia, 82% used laryngeal mask instead of endotracheal intubation during the opening sequence, and 71% during closure. Local and regional anesthesia was practiced by all the teams. The most frequently reported cause of pain was dural and cerebral vessels manipulation (77%). Pain management was mostly based on paracetamol (70%) and remifentanil (55%).

CONCLUSION

Our survey showed that there was an equivalent proportion of centers using SAS or MAC protocols in the anesthetic management of awake surgery in ELGGN centers. The advantages and disadvantages of each anesthesia protocol were reviewed.

The Future of Neuroimplantable Devices: A Materials Science and Regulatory Perspective

The past two decades have seen unprecedented progress in the development of novel materials, form factors, and functionalities in neuroimplantable technologies, including electrocorticography (ECoG) systems, multielectrode arrays (MEAs), Stentrode, and deep brain probes. The key considerations for the development of such devices intended for acute implantation and chronic use, from the perspective of biocompatible hybrid materials incorporation, conformable device design, implantation procedures, and mechanical and biological risk factors, are highlighted. These topics are connected with the role that the U.S. Food and Drug Administration (FDA) plays in its regulation of neuroimplantable technologies based on the above parameters. Existing neuroimplantable devices and efforts to improve their materials and implantation protocols are first discussed in detail. The effects of device implantation with regards to biocompatibility and brain heterogeneity are then explored. Topics examined include brain-specific risk factors, such as bacterial infection, tissue scarring, inflammation, and vasculature damage, as well as efforts to manage these dangers through emerging hybrid, bioelectronic device architectures. The current challenges of gaining clinical approval by the FDA-in particular, with regards to biological, mechanical, and materials risk factors-are summarized. The available regulatory pathways to accelerate next-generation neuroimplantable devices to market are then discussed.

Assessment of wakefulness during awake craniotomy to predict intraoperative language performance

OBJECTIVE

Maximal safe tumor resection in language areas of the brain relies on a patient's ability to perform intraoperative language tasks. Assessing the performance of these tasks during awake craniotomies allows the neurosurgeon to identify and preserve brain regions that are critical for language processing. However, receiving sedation and analgesia just prior to experiencing an awake craniotomy may reduce a patient's wakefulness, leading to transient language and/or cognitive impairments that do not completely subside before language testing begins. At present, the degree to which wakefulness influences intraoperative language task performance is unclear. Therefore, the authors sought to determine whether any of 5 brief measures of wakefulness predicts such performance during awake craniotomies for glioma resection.

METHODS

The authors recruited 21 patients with dominant hemisphere low- and high-grade gliomas. Each patient performed baseline wakefulness measures in addition to picture-naming and text-reading language tasks 24 hours before undergoing an awake craniotomy. The patients performed these same tasks again in the operating room following the cessation of anesthesia medications. The authors then conducted statistical analyses to investigate potential relationships between wakefulness measures and language task performance.

RESULTS

Relative to baseline, performance on 3 of the 4 objective wakefulness measures (rapid counting, button pressing, and vigilance) declined in the operating room. Moreover, these declines appeared in the complete absence of self-reported changes in arousal. Performance on language tasks similarly declined in the intraoperative setting, with patients experiencing greater declines in picture naming than in text reading. Finally, performance declines on rapid counting and vigilance wakefulness tasks predicted performance declines on the picture-naming task.

CONCLUSIONS

Current subjective methods for assessing wakefulness during awake craniotomies may be insufficient. The administration of objective measures of wakefulness just prior to language task administration may help to ensure that patients are ready for testing. It may also allow neurosurgeons to identify patients who are at risk for poor intraoperative performance.

Awake craniotomy in glioma surgery: is it necessary?

INTRODUCTION

The awake craniotomy has evolved from its humble beginnings in ancient cultures to become one of the most eloquent modern neurosurgical procedures. The development of intraoperative mapping techniques like direct electrostimulation of the cortex and subcortical white matter have further argued for its place in the neurosurgeon's armamentarium. Yet the suitability of the awake craniotomy with intraoperative functional mapping (ACWM) to optimize oncofunctional balance after peri-eloquent glioma resection continues to be a topic of active investigation as new methods of intraoperative monitoring and some unfavorable outcome data question its necessity.

EVIDENCE ACQUISITION

The neurosurgery and anesthesiology literatures were scoured for English-language studies that analyzed or reviewed the ACWM or its components as applied to glioma surgery via the PubMed, ClinicalKey, and OvidMEDLINE® databases or via direct online searches of journal archives.

EVIDENCE SYNTHESIS

Information on background, conceptualization, standard techniques, and outcomes of the ACWM were provided and compared. We parceled the procedure into its components and qualitatively described positive and negative outcome data for each. Findings were presented in the context of each study without attempt at quantitative analysis or reconciliation of heterogeneity between studies. Certain illustrative studies were highlighted throughout the review. Overarching conclusions were drawn based on level of evidence, expert opinion, and predominate concordance of data across studies in the literature.

CONCLUSIONS

Most investigators and studies agree that the ACWM is the best currently available approach to optimize oncofunctional balance in this difficult-to-treat patient population. This qualitative review synthesizes the most currently available data on the topic to provide contemporaneous insight into how and why the ACWM has become a favorite operation of neurosurgeons worldwide for the resection of gliomas from eloquent brain.

Awake craniotomy without sedation in treatment of patients with lesional epilepsy

BACKGROUND

The use of awake craniotomy for surgical treatment of epilepsy was applied in surgery of convexital tumors, arteriovenous malformations, some superficial aneurysms, and stereotactic neurosurgery. The aim of this study was to show the advantages of awake craniotomy without sedation, accompanied by intraoperative neurophysiological monitoring in patients with symptomatic epilepsy.

METHODS

This article describes the results of surgical treatment in 41 patients with various pathologies; 31 among them suffered from epilepsy.

RESULTS

Most frequently, the pathological foci were located in frontal and parietal lobes nearby eloquent brain areas. Irrespective of damage location, simple partial and complex partial seizures were seen almost with the same frequency. Intraoperative mapping of eloquent cortical areas and subcortical tracts without sedation resulted in total resection of pathological area in 75% of cases with low rate of permanent neurological deficit (two patients). Minor perioperative complications, including the decrease in blood pressure in six patients and intraoperative convulsions in two patients, were handled and did not led to operation termination or anesthesia conversion. Excellent seizures control (Engel 1) was achieved in 80% of patients with available catamnesis.

CONCLUSION

Thus, the proposed method allows eliminating the complications associated with sedation and provides radical resection of pathological epileptogenic foci with low complication rate.

[Anesthetic considerations for awake craniotomy: case report]

BACKGROUND AND OBJECTIVES

The conscious patient cooperation during neurological procedures has become necessary for the delimitation of areas to be managed by a neurosurgeon, with better results in the treatment of tumor lesions, vascular or epileptic foci, and lesser sequelae. The need for perioperative awareness (responsiveness to commands) challenges anesthesiologists to further ensure patient safety during the procedure. Several techniques have been described for this purpose.

CASE REPORT

In this case, interaction with the patient during brain tumor resection enabled a broad approach of the tumor lesion, limited by deficits in speech and naming observed during surgical manipulation, avoiding major consequences. The chosen technique was deepening of general anesthesia during surgical times of most painful stimulus with intraoperative awakening of the patient.

CONCLUSIONS

Patient selection, an exhaustive explanation of the procedure to him, and the selection of drugs are crucial for a successful procedure. Laryngeal mask is useful in times requiring greater depth and anesthetic ventilation control, primarily in situations where endotracheal intubation may be hindered by the position. The continuous infusion of remifentanil and adjuncts in the awake period associated adequate analgesia and full consciousness.

Comparative analysis of monotherapy versus duotherapy antiseizure drug management for postoperative seizure control in patients undergoing an awake craniotomy

OBJECTIVE Postoperative seizures are a common complication in patients undergoing an awake craniotomy, given the cortical manipulation during tumor resection and the electrical cortical stimulation for brain mapping. However, little evidence exists about the efficacy of postoperative seizure prophylaxis. This study aims to determine the most appropriate antiseizure drug (ASD) management regimen following an awake craniotomy. METHODS The authors performed a retrospective analysis of data pertaining to patients who underwent an awake craniotomy for brain tumor from 2007 to 2015 performed by a single surgeon. Patients were divided into 2 groups, those who received a single ASD (the monotherapy group) and those who received 2 types of ASDs (the duotherapy group). Patient demographics, symptoms, tumor characteristics, hospitalization details, and seizure outcome were evaluated. Multivariable logistic regression was used to evaluate numerous clinical variables associated with postoperative seizures. RESULTS A total of 81 patients underwent an awake craniotomy for tumor resection of an eloquent brain lesion. Preoperative baseline characteristics were comparable between the 2 groups. The postoperative seizure rate was 21.7% in the monotherapy group and 5.7% in the duotherapy group (p = 0.044). Seizure outcome at 6 months' follow-up was assessed with the Engel classification scale. The duotherapy group had a significantly higher proportion of seizure-free (Engel Class I) patients than the monotherapy group (90% vs 60%, p = 0.027). The length of stay was similar, 4.02 days in the monotherapy group and 4.51 days in the duotherapy group (p = 0.193). The 90-day readmission rate was higher for the monotherapy group (26.1% vs 8.5% in the duotherapy group, p = 0.044). Multivariate logistic regression showed that preoperative seizure history was a significant predictor for postoperative seizures following an awake craniotomy (OR 2.08, 95% CI 0.56-0.90, p < 0.001). CONCLUSIONS Patients with a preoperative seizure history may be at a higher risk for postoperative seizures following an awake craniotomy and may benefit from better postoperative seizure control with postoperative ASD duotherapy.

Anesthesia considerations in epilepsy surgery

Epilepsy surgeries can be done under general anesthesia or with local anesthesia and sedation. Epilepsy surgery done under general anesthesia have similar goals as any other neurosurgical procedure, except in patients with temporal lobe epilepsy requiring cortical mapping or electrocorticography (ECoG) where depth of anesthesia has to be reduced. Since seizure focus localization can be done preoperatively with modern diagnostic tools, general anesthesia is popular even for these patients. It is comfortable for both the surgeon and the patient. For intraoperative ECoG or cortical mapping awake craniotomy is the preferred technique.