Awake craniotomy versus surgery under general anesthesia for resection of intrinsic lesions of eloquent cortex—A prospective randomised study

doi:10.1016/j.clineuro.2007.01.008

Clinical Neurology and Neurosurgery

Volume 109, Issue 4, May 2007, Pages 335-343

https://doi.org/10.1016/j.clineuro.2007.01.008 Get rights and content

Abstract

Objectives

Complete removal of a brain tumor without inflicting neurological deficits is a desirable end result in neurosurgical practice. Currently no prospective randomized surgical series in the literature exists comparing tumor resection under general versus local anesthesia awake surgery may achieve more aggressive tumor resection and minimize postoperative neurological morbidity.

Patient and methods

We thence conducted a prospective randomized comparative study of results of surgery under awake versus surgery under general anesthesia for intrinsic eloquent area lesions. Fifty-three patients with intrinsic brain tumors in eloquent areas were prospectively randomized (26 patients in awake group and 27 for surgery under general anesthesia). At 3 months follow up, 23% patients in awake group had permanent deficits compared to 14.8% in GA group.

Results

More than 90% tumor excision was observed in 57% patients in awake group versus 73.7% in GA group.

Conclusions

The mean operative time, blood loss was found to be was found to be less in GA group patients than in awake group. Better tumor cytoreduction, neurological improvement was seen in GA group (motor improvement in 35.7%, speech improvement in 62.5%) than in awake group patients (motor improvement in 18.7%, speech improvement in 14.3%).

Introduction

By performing the resection under awake conditions, the surgeon may be able to perform a more aggressive tumor resection while minimizing the chances of postoperative neurological morbidity [1], [2], [3], [4]. Surgical resection of supratentorial gliomas and other intrinsic lesions of the brain are often limited by the location and spatial extent of the tumor and its relationship to the eloquent tissue [2], [3], [4]. Traditionally these patients are operated under general anesthesia and postoperative neurological deficits may develop in them due to retraction, edema, and/or resection of surrounding eloquent areas [5]. Primary intraaxial tumors may be safely resected if the resection remains within the confines of the lesion especially more so when the tumor is located within the functional areas assuming that the adjacent normal-appearing cortex and subcortical white matter is not disturbed. Awake craniotomy not only enables a safe corridor into the cortex but may also facilitate a wider resection of the tumor as a direct real time clinical monitoring is possible [6], [7]. Even though there have been a number of reports in the literature describing surgery under awake conditions, there are no proper prospectively randomized studies available [7], [8], [9], [10], [11], [12]. Hence this study was carried out to analyze prospectively the usefulness of awake craniotomy for intrinsic lesions of brain involving the eloquent cortex in preventing development of fresh neurological deficits and in achieving greater radical resection as compared to those cases operated under general anesthesia. To the best of our knowledge, this is the only such study, which has attempted to objectively define the efficacy of awake surgery for lesions situated in eloquent cortex by comparing it with similarly matched cases in the GA group.

Section snippets

Patient and methods

Fifty-three patients with intrinsic brain lesions in eloquent areas admitted for surgery between January 2001 and May 2003 were included in this prospective randomized study. Computer generated random number allocation by an independent person not involved in operating these patients was used to randomize patients into two groups viz awake and GA groups. The primary objective of the study was to compare the efficacy of surgery under awake conditions with surgery under general anesthesia for

Results demographic profile of patients

The mean age was 42.7 years in awake group and 41.3 years in GA group. The two groups were comparable in age/sex/location of lesions on statistical analysis (Table 1).

Discussion

Despite advances in functional MRI and neuronavigation techniques that allow anatomic localization of brain function under general anesthesia, real time feedback regarding the patient's neurological status remains a distinct advantage of the awake craniotomy procedure [9], [14]. The traditional maxim that by debulking a tumor from within and thus avoids new neurological deficits may not be valid because both high and low grade gliomas have been reported to contain functional tissue [5], [15].

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Awake craniotomy for high-grade gliomas – a prospective cohort study in a UK tertiary-centre
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A prospective review of all patients who underwent AC for HGG from 2013 to 2019 were performed. Data on patient characteristics including but not limited to demographics, pre- and post-operative Karnofsky performance status (KPS), tumour location and volume, type of surgery, extent of resection (EOR), tumour histopathology, intra- and post-operative complications, morbidity, mortality, disease recurrence, progression-free survival (PFS) and overall survival (OS) from the time of surgery were collected.
Fifteen patients (6 males; 9 females; 17 surgeries) underwent AC for HGG (median age = 55 years). Two patients underwent repeat surgeries due to disease recurrence. Median pre- and post-operative KPS score was 90 (range:80–100) and 90 (range:60–100), respectively. The EOR ranges from 60 to 100 % with a minimum of 80 % achieved in 81.3 % cases. Post-operative complications include focal seizures (17.6 %), transient aphasia/dysphasia (17.6 %), permanent motor deficit (11.8 %), transient motor deficit (5.9 %) and transient sensory disturbance (5.9 %). There were no surgery-related mortality or post-operative infection. The median PFS and OS were 13 (95%CI 5–78) and 30 (95%CI 21–78) months, respectively.
This is the first study in the UK to solely report outcomes of AC for HGG surgery. Our data demonstrates that AC for HGG in eloquent region is safe, feasible and provides comparable outcomes to those reported in the literature.
Corticocortical Evoked Potentials in Eloquent Brain Tumor Surgery. A Systematic Review
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Eloquent brain tumor surgery involves the delicate task of resecting tumors located in regions of the brain responsible for critical functions, such as language, motor control, and sensory perception. Preserving these functions is of paramount importance to maintain the patient's quality of life. Corticocortical evoked potentials (CCEPs) have emerged as a valuable intraoperative monitoring technique that aids in identifying and preserving eloquent cortical areas during surgery. This systematic review aimed to assess the utility of CCEPs in eloquent brain tumor surgery and determine their effectiveness in improving patient outcomes. A comprehensive literature search was conducted using electronic databases, including PubMed/Medline and Scopus. The search strategy identified 11 relevant articles for detailed analysis. The findings of the included studies consistently demonstrated the potential of CCEPs in guiding surgical decision making, minimizing the risk of postoperative neurological deficits, and mapping functional connectivity during surgery. However, further research and standardization are needed to fully establish the clinical benefits and refine the implementation of CCEPs in routine neurosurgical practice.
The current state of the art of primary motor mapping for tumor resection: A focused survey
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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.
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.
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.
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.
Passive functional mapping of receptive language cortex during general anesthesia using electrocorticography
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To investigate the feasibility of passive functional mapping in the receptive language cortex during general anesthesia using electrocorticographic (ECoG) signals.
We used subdurally placed ECoG grids to record cortical responses to speech stimuli during awake and anesthesia conditions. We identified the cortical areas with significant responses to the stimuli using the spectro-temporal consistency of the brain signal in the broadband gamma (BBG) frequency band (70–170 Hz).
We found that ECoG BBG responses during general anesthesia effectively identify cortical regions associated with receptive language function. Our analyses demonstrated that the ability to identify receptive language cortex varies across different states and depths of anesthesia. We confirmed these results by comparing them to receptive language areas identified during the awake condition. Quantification of these results demonstrated an average sensitivity and specificity of passive language mapping during general anesthesia to be 49 $\pm$ 7.7% and 100%, respectively.
Our results demonstrate that mapping receptive language cortex in patients during general anesthesia is feasible.
Our proposed protocol could greatly expand the population of patients that can benefit from passive language mapping techniques, and could eliminate the risks associated with electrocortical stimulation during an awake craniotomy.
Launching Awake Craniotomy Technique in a Resource-Limited Center: New Insights into the Patient Experience, Costs, and Long-Term Outcomes and a Narrative Review of the Literature
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Awake craniotomy (AC) with brain mapping is a standard surgical technique for the excision of lesions located in eloquent areas. We aimed to assess the clinical challenges, patient experience, costs, and long-term outcomes of AC in a resource-limited setting.
In this cross-sectional study, electronic documents of 12 patients who underwent AC with functional brain mapping were prospectively collected from August 2017 to October 2020. Patient characteristics, surgical specifications, hospitalization period, intraoperative and postoperative events, functional outcome, patients’ satisfaction, costs, and survivals were collected and analyzed.
Twelve patients with a median age of 42.5 (interquartile range, 13.5) were enrolled, of whom 8 were male (66.7%), and 9 (75%) were harboring grade 2 glioma. Of the patients, 8.34%, 33.34%, and 58.33% had partial, subtotal, and gross total excision of the tumors, respectively. The intraoperative seizure was the only complication and occurred in 2 cases (16.67%). At 1 year follow-up, none of the patients experienced any neurologic deficit. Eleven patients (91.6%) had a satisfactory opinion about reappearing in the AC. At 38 months follow-up, mortality was 8% for AC group and 25% among the historically matched controls who had surgery under general anesthesia (P = 0.27). Most costs belonged to the neurosurgery team (43%), and the overall expenses were reduced by 13% compared with a putatively well-equipped setting in our country.
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Citation Excerpt :
In these cases, the two primary tools to guide resection and provide real-time intraoperative feedback are awake and asleep cortical mapping. Several studies have directly compared the postoperative rates of transient and permanent deficits after awake versus asleep mapping [6,27,29–31], but not in patient populations large enough to determine the superiority of one technique compared to the other. Our results suggest that awake and asleep motor mapping result in comparable rates of transient and long-term neurological deficits after eloquent brain tumor resection.
Cortical mapping has been used as a tool to ensure maximal safe resection of intracranial tumors for several decades. Post-surgical motor and language deficits, including seizures, weakness, aphasia, and dysarthria have been well-documented in patients undergoing these operations, particularly on eloquent cortical regions. However, it is not known whether awake versus asleep cortical mapping contributes to differences in postoperative neurological deficits.
A comprehensive review of the literature utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was completed for articles describing cortical mapping for tumor resection. We critically assessed all articles published in the last 20 years describing complications of patients who had undergone either awake or asleep motor mapping for eloquent brain tumor resection. Studies were analyzed for number of patients, follow-up duration, rates of transient and permanent motor and sensory deficits in the perioperative period, and outcomes at one-month follow-up.
Thirty-one studies met inclusion criteria, 24 of which reported long-term post-operative follow-up data. Follow-up among selected studies ranged from one month to four years. Nine of the 31 studies directly compared the postoperative outcomes of awake versus asleep mapping. The rate of transient deficits among patients who underwent awake and asleep mapping was 31.6% and 32.7%, respectively. The rate of permanent deficits was 10.8% in awake mapping patients and 12.7% in asleep mapping patients. Qualitative analysis showed that motor and sensory complications occurred at similar rates.
Review of the current evidence suggests that the rates of transient and permanent postoperative neurologic deficits among awake versus asleep cortical mapping groups are similar. Thus, use of both techniques is reasonable to minimize perioperative morbidity.

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Awake craniotomy versus surgery under general anesthesia for resection of intrinsic lesions of eloquent cortex—A prospective randomised study

Abstract

Objectives

Patient and methods

Results

Conclusions

Introduction

Section snippets

Patient and methods

Results demographic profile of patients

Discussion

Mayo Clin Proc

Radiother Oncol

The effect of extent of resection on recurrence in patients with low grade cerebral hemisphere gliomas

Cancer

Brain mapping techniques to maximize resection, safety and seizure control in children with brain tumors

Neurosurgery

Cortical mapping for defining the limits of tumor resection

Neurosurgery

Cortical mapping and local anesthetic resection as an aid to surgery of low and intermediate grade gliomas

Br J Neurosurg

Functional cortex and subcortical white matter located within glioma

Neurosurgery

A note upon the faradic stimulation of the precentral gyrus in conscious patients

Brain

Safety in surgery of lesions near the motor cortex using intraoperative mapping techniques. A report on 50 patients

Acta Neurochir (Wien)

Patient tolerance of craniotomy performed with the patient under local anesthesia and monitored conscious sedation

Neurosurgery