Is a wake-up call in order? Review of the evidence for awake craniotomy

Anesthetic Management for Awake Craniotomy Applied to Neurosurgery

Our anesthetic technique proposed for awake craniotomy is the monitored anesthesia care (MAC) technique, with the patient in sedation throughout the intervention. Our protocol involves analgo-sedation through the administration of dexmedetomidine and remifentanil in a continuous intravenous infusion, allowing the patient to be sedated and in comfort, but contactable and spontaneously breathing. Pre-surgery, the patient is pre-medicated with intramuscular clonidine (2 µg/kg); it acts both as an anxiolytic and as an adjuvant in pain management and improves hemodynamic stability. In the operating setting, dexmedetomidine in infusion and remifentanil in target controlled infusion (TCI) for effect are started. The purpose of the association is to exploit the pharmacodynamics of dexmedetomidine which guarantees the control of respiratory drive, and the pharmacokinetics of remifentanil characterized by insensitivity to the drug. Post-operative management: at the end of the surgical procedure, the infusion of drugs was suspended. Wake-up craniotomy is associated with reduced hospital costs compared to craniotomy performed in general anesthesia, mainly due to reduced costs in the operating room and shorter hospital stays. Greater patient satisfaction and the benefits of avoiding hospital stay have led to the evolution of outpatient intracranial neurosurgery.

Multimodal mapping and monitoring is beneficial during awake craniotomy for intra-cranial tumours: results of a dual centre retrospective study

BACKGROUND

The combination of awake craniotomy with multimodal neurophysiological mapping and monitoring in intra-axial tumour resection is not well described, but may have theoretical benefits which we sought to investigate.

METHODS

All patients undergoing awake craniotomy for tumour resection with cortical and/or subcortical stimulation together with one or more of electrocorticography (ECoG/EEG), motor or somatosensory evoked potentials were identified from the operative records of two surgeons at two centres over a 5 year period. Patient, operative and outcome data were collated. Statistical analysis was performed to evaluate factors predictive of intra-operative seizures and surgical outcomes.

RESULTS

83 patients with a median age 50 years (18-80 years) were included. 80% had gliomas (37% low grade) and 13% metastases. Cortical mapping was negative in 35% (language areas) and 24% (motor areas). Complete or near total resection was achieved in 80% with 5% severe long-term neurological deficits. Negative cortical mapping was combined with positive subcortical mapping in 42% with no significant difference in extent of resection rates to patients undergoing positive cortical mapping (p = 0.95). Awake mapping could not be completed in 14%, but with no compromise to extent of resection (p = 0.55) or complication rates (p = 0.09). Intraoperative seizures occurred in 11% and were significantly associated with intra-operative EEG spikes (p = 0.003).

CONCLUSIONS

Awake multi-modal monitoring is a safe and well tolerated technique. It provides preservation of extent of resection and clinical outcomes in cases of aborted awake craniotomy. Negative cortical mapping in combination with positive subcortical mapping was also shown to be safe, although not hitherto well described. Electrocorticography further enables the differentiation of seizure activity from true positive mapping, and the successful treatment of spikes prior to full clinical seizures occurring.

Predictors for time to awake in patients undergoing awake craniotomies

OBJECTIVE

Awake craniotomies are often characterized by alternating asleep-awake-asleep periods. Preceding the awake phase, patients are weaned from anesthesia and mechanical ventilation. Although clinicians aim to minimize the time to awake for patient safety and operating room efficiency, in some patients, the time to awake exceeds 20 minutes. The goal of this study was to determine the average time to awake and the factors associated with prolonged time to awake (> 20 minutes) in patients undergoing awake craniotomy.

METHODS

Records of patients who underwent awake craniotomy between 2003 and 2020 were evaluated. Time to awake was defined as the time between discontinuation of propofol and remifentanil infusion and the time of extubation. Patient and perioperative characteristics were explored as predictors for time to awake using logistic regression analyses.

RESULTS

Data of 307 patients were analyzed. The median (IQR) time to awake was 13 (10-20) minutes and exceeded 20 minutes in 17% (95% CI 13%-21%) of the patients. In both univariate and multivariable analyses, increased age, nonsmoker status, and American Society of Anesthesiologists (ASA) class III versus II were associated with a time to awake exceeding 20 minutes. BMI, as well as the use of alcohol, drugs, dexamethasone, or antiepileptic agents, was not significantly associated with the time to awake.

CONCLUSIONS

While most patients undergoing awake craniotomy are awake within a reasonable time frame after discontinuation of propofol and remifentanil infusion, time to awake exceeded 20 minutes in 17% of the patients. Increasing age, nonsmoker status, and higher ASA classification were found to be associated with a prolonged time to awake.

Life after surgical resection of a low-grade glioma: A prospective cross-sectional study evaluating health-related quality of life

Health related quality of life (HRQoL) has become an important consideration in LGG patients. We report the largest prospective, longitudinal, cross-sectional cohort study of HRQoL in LGG patients, aiming to identify actionable determinants of HRQoL. Post-operative LGG adults at a large tertiary center underwent HRQoL assessment using the EORTC QLQ-C30 questionnaire administered at follow-up visits and by mail. Scores at 12 month intervals were compared with those from a normative reference population. Spearman's Rho was used to evaluate correlation of subdomain and symptom scores with global HRQoL and change over time. There were 167 participants and 366 questionnaires analysed. Patients reported reduced global HRQoL at nearly every 12 month interval with significant impairments at 12, 72, 108, and 120+ months postoperative. They also reported a significant impairment in each functional subdomain at 12 months, which persisted to varying degrees over 120 months, as did significant fatigue and insomnia. Role, emotional, and social subdomains, as well as fatigue, were significantly associated with global HRQoL at the first 12 month interval. Overall, there was no significant correlation between time from surgery and global HRQoL or the subdomain functional or symptom sections of the QLQ-C30. LGG patients report considerable, sustained impairments in HRQoL after surgery, particularly in cognitive, emotional, and social function, as well as suffering significant fatigue and insomnia. These are strongly associated with global HRQoL and thus can be considered determinants of global HRQoL that with intervention, may improve HRQoL for our LGG patients. This is the largest prospective longitudinal study of HRQoL in postoperative LGG patients yet reported and is ongoing. It identifies several determinants of impaired HRQoL with available management options and interventions that have the potential to significantly improve HRQoL in these patients.

Neurocognitive Impairment After Propofol With Relevance for Neurosurgical Patients and Awake Craniotomies-A Prospective Observational Study

Background: Short-acting anesthetics are used for rapid recovery, especially for neurological testing during awake craniotomy. Extent and duration of neurocognitive impairment are ambiguous.

Methods: Prospective evaluation of patients undergoing craniotomy for tumor resection during general anesthesia with propofol (N of craniotomies = 35). Lexical word fluency, digit span and trail making were tested preoperatively and up to 24 h after extubation. Results were stratified for age, tumor localization and hemisphere of surgery. Results in digit span test were compared to 21 patients during awake craniotomies.

Results: Word fluency was reduced to 30, 33, 47, and 87% of preoperative values 10, 30, 60 min and 24 h after extubation, respectively. Digit span was decreased to 41, 47, 55, and 86%. Performances were still significantly impaired 24 h after extubation, especially in elderly. Results of digit span test were not worse in patients with left hemisphere surgery. Significance of difference to baseline remained, when patients with left or frontal lesions, i.e., brain areas essential for these tests, were excluded from analysis. Time for trail making was increased by 87% at 1 h after extubation, and recovered within 24 h. In 21 patients undergoing awake craniotomies without pharmacological sedation, digit span was unaffected during intraoperative testing.

Conclusion: Selected aspects of higher cognitive functions are compromised for up to 24 h after propofol anesthesia for craniotomy. Propofol and the direct effects of surgical resection on brain networks may be two major factors contributing (possibly jointly) to the observed deficits. Neurocognitive testing was unimpaired in patients undergoing awake craniotomies without sedation.

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.

Awake Craniotomy in a Patient With History of Post-Traumatic Stress Disorder-A Clinical Dilemma: A Case Report

A 32-year-old man undergoing awake craniotomy for tumor resection was previously diagnosed with post-traumatic stress disorder (PTSD)-typically a relative contraindication for awake craniotomy. Preoperative neurocognitive assessment and counseling by a neuroanesthesiologist and neuropsychologist were undertaken to characterize his PTSD, identify triggers, and prepare him for the intraoperative events. Dexmedetomidine and remifentanil were used as intraoperative anxiolytics and analgesics. With an emphasis on open communication, the patient tolerated the awake craniotomy without complications. This case highlights the importance of multidisciplinary approach and meticulous perioperative preparation in successfully managing a patient who might otherwise be contraindicated for awake craniotomy.

Awake brain surgery in children-review of the literature and state-of-the-art

OBJECTIVE

Awake brain surgery (ABS) is poorly reported in children as it is considered having limited indications due to age and neuropsychological aspects interfering with its feasibility and psychological outcome. The aim of this article is to review the current state-of-the-art of ABS in children and to offer an objective summary of the published literature on diversified outcome aspects of pediatric awake procedures.

METHODS

A literature review was performed using the MEDLINE (PubMed) electronic database applying the following MeSH terms to the keyword search within titles and abstracts: "awake brain surgery children," "awake brain surgery pediatric," "awake craniotomy children," "awake craniotomy pediatric," and "awake surgery children." Of the initial 753 results obtained from these keyword searches, a full text screening of 51 publications was performed, ultimately resulting in 18 eligible articles for this review.

RESULTS

A total of 18 full text articles reporting the results of 50 patients were included in the analysis. Sixteen of the 18 studies were retrospective studies, comprising 7 case series, 9 case reports, and 2 reviews. Eleven studies were conducted from anesthesiological (25 patients) and 7 from neurosurgical (25 patients) departments. Most of the patients underwent ABS for supratentorial lesions (26 patients), followed by epilepsy surgery (16 patients) and deep brain stimulation (DBS) (8 patients). The median age was 15 years (range 8-17 years). Persistent deficits occurred in 6 patients, (12%), corresponding to minor motor palsies (4%) and neuropsychological concerns (8%). An awake procedure was aborted in 2 patients (4%) due to cooperation failure and anxiety, respectively.

CONCLUSIONS

Despite well-documented beneficial aspects, ABS remains mainly limited to adults. This review confirms a reliable tolerability of ABS in selected children; however, recommendations and guidelines for its standardized implementation in this patient group are pending. Recommendations and guidelines may address diagnostic workup and intra-operative handling besides criteria of eligibility, psychological preparation, and coordinated neuropsychological testing in order to routinely offer ABS to children.

The Stony Brook awake craniotomy protocol: A technical note

Most current awake craniotomy techniques utilize unnecessarily complicated airway management, and cause discomfort to the patients during the awake phase of the surgery. Our manuscript is written to discuss the neurosurgical and anesthetic techniques that we have developed to optimize awake craniotomy techniques at Stony Brook University Medical Center. We used the frameless Brainlab™ skull-mounted array for stereotactic navigation. Rigid fixation of the skull was avoided. General anesthesia with established airway was used during the "asleep" phase of the surgery. Following the removal of the bone flap and the opening of the dura, the patients were woken up, and the established airway was removed. Cortical mapping was performed to establish a safe entry zone for tumor removal. While the tumors were being removed, we continued motor examination and casual conversation with the patients to ensure safety. Patients were sedated during the remaining phase of the surgery until skin closure. No patient exhibited any neurological deficits or adverse anesthesia outcomes during the postoperative period. The protocol we developed avoids rigid skull fixation and emphasizes flexible intraoperative planning, thereby maximizing patient and physician comfort while allowing for successful tumor resection.

The impact of surgery in molecularly defined low-grade glioma: an integrated clinical, radiological, and molecular analysis

Background

Extensive resections in low-grade glioma (LGG) are associated with improved overall survival (OS). However, World Health Organization (WHO) classification of gliomas has been completely revised and is now predominantly based on molecular criteria. This requires reevaluation of the impact of surgery in molecularly defined LGG subtypes.

Methods

We included 228 adults who underwent surgery since 2003 for a supratentorial LGG. Pre- and postoperative tumor volumes were assessed with semiautomatic software on T2-weighted images. Targeted next-generation sequencing was used to classify samples according to current WHO classification. Impact of postoperative volume on OS, corrected for molecular profile, was assessed using a Cox proportional hazards model.

Results

Median follow-up was 5.79 years. In 39 (17.1%) histopathologically classified gliomas, the subtype was revised after molecular analysis. Complete resection was achieved in 35 patients (15.4%), and in 54 patients (23.7%) only small residue (0.1-5.0 cm3) remained. In multivariable analysis, postoperative volume was associated with OS, with a hazard ratio of 1.01 (95% CI: 1.002-1.02; P = 0.016) per cm3 increase in volume. The impact of postoperative volume was particularly strong in isocitrate dehydrogenase (IDH) mutated astrocytoma patients, where even very small postoperative volumes (0.1-5.0 cm) already negatively affected OS.

Conclusion

Our data provide the necessary reevaluation of the impact of surgery in molecularly defined LGG and support maximal resection as first-line treatment for molecularly defined LGG. Importantly, in IDH mutated astrocytoma, even small postoperative volumes have negative impact on OS, which argues for a second-look operation in this subtype to remove minor residues if safely possible.

Who Needs Sleep? An Analysis of Patient Tolerance in Awake Craniotomy

BACKGROUND

Awake craniotomy (AC) is generally a safe and effective procedure; however, a small but not insignificant portion of cases are aborted due to patient intolerance of the awake portion of surgery. There is not yet a firm understanding of what characteristics indicate patient tolerance or failure of AC.

METHODS

We retrospectively reviewed a single-surgeon database of patients treated by AC over a 5-year period. Charts were reviewed for demographic, clinical, and operative characteristics, including anesthetic administration during the awake portion of surgery. Statistical analysis was performed to determine which factors predicted patient tolerance or failure.

RESULTS

Our study cohort comprised 120 patients with an average age of 56.0 ± 15.2 years. A majority of patients were male (55.8%). The most common surgical indication was tumor (95.8%), with gliobastoma as the most common diagnosis (43.3%). Male sex predicted surgical tolerance on univariate analysis (P = 0.015). Remifentanil administration was associated with surgical failure on univariate analysis (P = 0.068), and also predicted failure on multivariate analysis (P = 0.030). Preoperative seizure, ketamine administration, and right-sided surgery each predicted patient tolerance, but did not achieve statistical significance. Similarly, respiratory comorbidity was associated with surgical failure, but did not achieve significance.

CONCLUSIONS

AC remains an effective treatment option; the majority of patients tolerate the procedure without issue. Male patients have lower rates of surgical failure, whereas remifentanil administration may increase failure rate.

Network Plasticity and Intraoperative Mapping for Personalized Multimodal Management of Diffuse Low-Grade Gliomas

Gliomas are the most frequent primary brain tumors and include a variety of different histological tumor types and malignancy grades. Recent achievements in terms of molecular and imaging fields have created an unprecedented opportunity to perform a comprehensive interdisciplinary assessment of the glioma pathophysiology, with direct implications in terms of the medical and surgical treatment strategies available for patients. The current paradigm shift considers glioma management in a comprehensive perspective that takes into account the intricate connectivity of the cerebral networks. This allowed significant improvement in the outcome of patients with lesions previously considered inoperable. The current review summarizes the current theoretical framework integrating the adult human brain plasticity and functional reorganization within a dynamic individualized treatment strategy for patients affected by diffuse low-grade gliomas. The concept of neuro-oncology as a brain network surgery has major implications in terms of the clinical management and ensuing outcomes, as indexed by the increased survival and quality of life of patients managed using such an approach.

IDH1 mutation may not be prognostically favorable in glioblastoma when controlled for tumor location: A case-control study

Isocitrate dehydrogenase 1 (IDH1) mutation is a known prognostic factor in glioblastoma multiforme (GBM). It has been well documented that patients with IDH1 mutant (IDH1-mu) GBM have a better outcome compared to patients with IDH1 wild-type (IDH1-WT) GBM. IDH1-mu tumors have been shown to be more commonly located in the frontal lobe, and less likely to be in multiple lobes. It is unclear whether differential location is part of the prognostically favorable profile of these tumors. We performed a case-control study, matching IDH1-mu GBMs to IDH1-WT GBMs that are controlled for age, sex and tumor location. There were 21 IDH1-mu tumors and 21 matched IDH1-WT tumors. Age, sex and tumor location were matched between the two groups. After controlling for the factors described, the IDH1-mu tumors were more likely to be secondary GBM (61.9% secondary vs. 14.3%, p=0.004). There was an insignificant trend towards smaller tumor volume in the IDH1-mu group (28.13±6.56 vs. 41.8±7.33 cm³, p=0.173). Extent of surgical resection was similar in both groups (mean 84.49% vs. 89.89%, p=0.419). There was no survival advantage for IDH1-mu tumors when controlled for location: 25.2months overall survival for IDH1-mu patients and 23.6 for IDH1-WT patients, p=0.794. IDH1 mutation may provide part of its prognostic significance by differential localization of tumor, both making IDH1-mu tumors more amenable to gross total resection and placing these tumors in less eloquent areas, thereby lowering neurological morbidity.