Anaesthesia Management for Awake Craniotomy: Systematic Review and Meta-Analysis

Abstract

BackgroundAwake craniotomy (AC) renders an expanded role in functional neurosurgery. Yet, evidence for optimal anaesthesia management remains limited. We aimed to summarise the latest clinical evidence of AC anaesthesia management and explore the relationship of AC failures on the used anaesthesia techniques.MethodsTwo authors performed independently a systematic search of English articles in PubMed and EMBASE database 1/2007-12/2015. Search included randomised controlled trials (RCTs), observational trials, and case reports (n>4 cases), which reported anaesthetic approach for AC and at least one of our pre-specified outcomes: intraoperative seizures, hypoxia, arterial hypertension, nausea and vomiting, neurological dysfunction, conversion into general anaesthesia and failure of AC. Random effects meta-analysis was used to estimate event rates for four outcomes. Relationship with anaesthesia technique was explored using logistic meta-regression, calculating the odds ratios (OR) and 95% confidence intervals [95%CI].ResultsWe have included forty-seven studies. Eighteen reported asleep-awake-asleep technique (SAS), twenty-seven monitored anaesthesia care (MAC), one reported both and one used the awake-awake-awake technique (AAA). Proportions of AC failures, intraoperative seizures, new neurological dysfunction and conversion into general anaesthesia (GA) were 2% [95%CI:1–3], 8% [95%CI:6–11], 17% [95%CI:12–23] and 2% [95%CI:2–3], respectively. Meta-regression of SAS and MAC technique did not reveal any relevant differences between outcomes explained by the technique, except for conversion into GA. Estimated OR comparing SAS to MAC for AC failures was 0.98 [95%CI:0.36–2.69], 1.01 [95%CI:0.52–1.88] for seizures, 1.66 [95%CI:1.35–3.70] for new neurological dysfunction and 2.17 [95%CI:1.22–3.85] for conversion into GA. The latter result has to be interpreted cautiously. It is based on one retrospective high-risk of bias study and significance was abolished in a sensitivity analysis of only prospectively conducted studies.ConclusionSAS and MAC techniques were feasible and safe, whereas data for AAA technique are limited. Large RCTs are required to prove superiority of one anaesthetic regime for AC.

Conscious sedation with dexmedetomidine compared with asleep-awake-asleep craniotomies in glioma surgery: an analysis of 180 patients

“…Awake craniotomy has enabled gross-total resection of tumors within or next to highly eloquent regions, improving their medical management, while making microsurgery feasible. 26,27,35 Real-time patient feedback is crucial when aiming to achieve gross-total resection of these malignancies. Awake craniotomies represent a challenge for the anesthesiologist and the surgeon, especially due to possible pain and anxiety of the patient, and possible risks from seizures, vomiting, and aspiration.…”

“…All of these have been discussed in the literature. 15,16,24,31,32,35 The first two of these techniques have previously been applied at the Department of Neurosurgery, University Hospital of Münster. Given recent publications, we decided to maintain the nomenclature "conscious sedation."…”

“…Given recent publications, we decided to maintain the nomenclature "conscious sedation." 23,35 Since 2013, the department has solely been performing conscious sedation surgeries using the a2-receptor agonist dexmedetomidine as the only anesthetic drug. Dexmedetomidine acts as a sedative and induces amnesia and analgesia.…”

Feasibility of awake craniotomy in the pediatric population

“…Complications considered serious were those that could lead to a fatal event or major sequelae without any intervention from the anesthesiologist. These were defined prior to data collection based on previous reports of awake craniotomy both from the pediatric and the adult population, and included seizures, increased intracranial pressure (presence of “tight brain” as indicated by the neurosurgeon), respiratory depression (oxygen saturation below 90% and/or respiratory rate below 8 rpm), airway obstruction (blockage in any part of the airway with or without oxygen saturation below 90%), bradycardia (heart rate below 60 lpm), vomiting, or severe agitation. Mild complications included moderate pain (numeric pain scale score ≥ 6) or and systolic hypertension above 20% of baseline.…”

“…Similarly, data about the anesthetic technique are very scarce in the literature and frequently limited to case reports . Consequently, the anesthetic management of awake craniotomy in children is often inferred from adult practice …”