Intermittent general anesthesia with controlled ventilation for asleep-awake-asleep brain surgery: a prospective series of 140 gliomas in eloquent areas

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.

A Comparison of the Asleep-Awake Technique and Monitored Anesthesia Care During Awake Craniotomy: A 10-Year Analysis

Background Awake intracranial surgery with direct electrical stimulation (DES) is considered the gold standard for the resection of tumors affecting the eloquent areas of the brain. Awake craniotomy is a challenge for the anesthesiologist, as the patient's active cooperation is required throughout the operation. There are two frequent techniques, one is asleep-awake-asleep (AAA), and the other is called monitored anesthesia care (MAC). The AAA technique is the longer standing of the two and comprises general anesthesia followed by intraoperative awakening, which is necessary for neurological monitoring. In the present study, a comparison was made between the asleep-awake (AA) technique, a variation of the AAA anesthesia technique, and the MAC, which consists of a sedation that makes it possible to control pain and anxiety. Unlike the AA technique, the MAC does not involve the use of invasive airway devices. Objective The main objective was to contrast the two anesthetic management techniques for awake brain surgery used in our hospital. Methods A retrospective observational single-center study was performed consisting of a review of patient clinical records. The study sample comprised all patients above 18 years of age undergoing brain surgery through awake craniotomy between January 2013 and December 2022 at the Miguel Servet University Hospital (HUMS) in Zaragoza (Spain). Results Of the 79 patients included in the study, 39 were operated under AA anesthesia while the remaining 40 were operated under the MAC procedure. The main age of the participants was 52.8 years, the mean height was 169 cm, and the mean weight was 74.2 kg. No statistically significant differences were observed with respect to the patients' baseline characteristics, except for obesity which was more prevalent in the MAC group. In the MAC group, the airway was managed by means of nasal cannulas in all cases, with conversion to general anesthesia being required in only one instance. In the AA group, the laryngeal mask (LM) was used in 89.7% of the patients, and the endotracheal tube (ETT) in 10.3%. The surgical and anesthetic procedure duration was 15 and 20 minutes shorter in the MAC group, respectively. A reduction of almost 20 minutes in the anesthetic procedure and 15 minutes in the surgical one was observed. Tachycardia, desaturation, and airway complications were observed in four, five, and four patients respectively in the AA group but in none of the patients in the MAC group. The mean stay in the intensive care unit (ICU) and the mean postoperative hemoglobin levels between both groups were insignificant. Conclusions Both techniques analyzed in this study turned out to be equally safe and effective for brain tumor surgery in awake patients.

A Preoperative Scoring System to Predict Function-Based Resection Limitation Due to Insufficient Participation During Awake Surgery

BACKGROUND

Failure in achieving a function-based resection related to the insufficient patient's participation is a drawback of awake surgery.

OBJECTIVE

To assess preoperative parameters predicting the risk of patient insufficient intraoperative cooperation leading to the arrest of the awake resection.

METHODS

Observational, retrospective, multicentric cohort analysis enrolling 384 (experimental dataset) and 100 (external validation dataset) awake surgeries.

RESULTS

In the experimental data set, an insufficient intraoperative cooperation occurred in 20/384 patients (5.2%), leading to awake surgery failure in 3/384 patients (ie, no resection, 0.8%), and precluded the achievement of the function-based resection in 17/384 patients (ie, resection limitation, 4.4%). The insufficient intraoperative cooperation significantly reduced the resection rates (55.0% vs 94.0%, P < .001) and precluded a supratotal resection (0% vs 11.3%, P = .017). Seventy years or older, uncontrolled epileptic seizures, previous oncological treatment, hyperperfusion on MRI, and mass effect on midline were independent predictors of insufficient cooperation during awake surgery ( P < .05). An Awake Surgery Insufficient Cooperation score was then assessed: 96.9% of patients (n = 343/354) with a score ≤2 presented a good intraoperative cooperation, while only 70.0% of patients (n = 21/30) with a score >2 presented a good intraoperative cooperation. In the experimental data set, similar date were found: 98.9% of patients (n = 98/99) with a score ≤2 presented a good cooperation, while 0% of patients (n = 0/1) with a score >2 presented a good cooperation.

CONCLUSION

Function-based resection under awake conditions can be safely performed with a low rate of insufficient patient intraoperative cooperation. The risk can be assessed preoperatively by a careful patient selection.

Short-range axono-cortical evoked-potentials in brain tumor surgery: Waveform characteristics as markers of direct connectivity

OBJECTIVE

Intraoperative measurement of axono-cortical evoked potentials (ACEP) has emerged as a promising tool for studying neural connectivity. However, it is often difficult to determine if the activity recorded by cortical grids is generated by stimulated tracts or by spurious phenomena. This study aimed to identify criteria that would indicate a direct neurophysiological connection between a recording contact and a stimulated pathway.

METHODS

Electrical stimulation was applied to white matter fascicles within the resection cavity, while the evoked response was recorded at the cortical level in seven patients.

RESULTS

By analyzing the ACEP recordings, we identified a main epicenter characterized by a very early positive (or negative) evoked response occurring just after the stimulation artifact (<5 ms, |Amplitude| > 100 µV) followed by an early and large negative (or positive) monophasic evoked response (<40 ms; |Amplitude| > 300 µV). The neighboring activity had a different waveform and was attenuated compared to the hot-spot activity.

CONCLUSIONS

It is possible to distinguish the hotspot with direct connectivity to the stimulated site from neighboring activity using the identified criteria.

SIGNIFICANCE

The electrogenesis of the ACEP at the hotspot and neighboring activity is discussed.

Monitored Anesthesia Care Protocol for Awake Craniotomy and Patient's Perspective on the Procedure

OBJECTIVE

There is ongoing discussion on pros and cons in terms of different anesthesia protocols for awake craniotomy (AC) with direct brain stimulation. The aim of this study is to share our anesthesia protocol and present our patients' perspectives.

METHODS

We conducted an analysis of prospectively collected data from 53 (54 procedures) consecutive patients. Most of the patients (50) underwent surgery due to primary brain lesions. Eight procedures were performed in patients with lesions in the nondominant hemisphere for language. Four of all procedures were reoperations, and one patient was operated on in awake conditions twice. The psychological evaluation of patients was performed 2 times: 2 days before and after surgery. A visual analog scale for pain and stress levels as well as structured interviews was used.

RESULTS

Most patients tolerated ACwell. Patients reported that discomfort was mostly related to urinary catheter insertion, head holder placement, and temporal muscle detachment in cases of frontotemporal craniotomies. The intensity of stress measured with the visual analog scale before surgery was negatively associated with age and positively correlated with stress experienced in the operating room. In all patients, we were able to finish the procedure according to the monitored anesthesia care protocol without the need for conversion to general anesthesia. We observed 3 (5.6%) intraoperative seizures that required deepening of sedation.

CONCLUSION

AC using the monitored anesthesia care protocol was a safe and well-tolerated procedure with satisfactory patient experience. Extensive preoperative preparation should be considered a key part of the procedure.

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.

Monitored anesthesia care and asleep-awake-asleep techniques combined with multiple monitoring for resection of gliomas in eloquent brain areas: a retrospective analysis of 225 patients

BACKGROUND

Awake craniotomy (AC) has become gold standard in surgical resection of gliomas located in eloquent areas. The conscious sedation techniques in AC include both monitored anesthesia care (MAC) and asleep-awake-asleep (AAA). The choice of optimal anesthetic method depends on the preferences of the surgical team (mainly anesthesiologist and neurosurgeon). The aim of this study was to compare the difference in physiological and blood gas data, dosage of different drugs, the probability of switching to endotracheal intubation, and extent of tumor resection and dysfunction after operation between AAA and MAC anesthetic management for resection of gliomas in eloquent brain areas.

METHODS

Two-hundred and twenty-five patients with super-tentorial tumor located in eloquent areas underwent AC from 2009 to 2021 in Xijing Hospital. Forty-one patients underwent AAA technique, and the rest one-hundred eighty-four patients underwent MAC technique. Anesthetic management, dosage of different drugs, intraoperative complications, postoperative outcomes, adverse events, extent of resection and motor, and sensory and language dysfunction after operation were compared between MAC and AAA.

RESULT

There was no significant difference in gender, KPS score, MMSE score, glioma grade, type, and growth site between the patients in the two groups, except the older age of patients in MAC group than that in AAA group. During the whole process of operation, there were greater pulse pressure difference (P = 0.046), shorter operation time (P = 0.039), less dosage of remifentanil (P = 0.000), more dosage of dexmedetomidine (P = 0.013), more use of antiemetics (81%, P = 0.0067), lower use of vasoactive agent (45.1%, P = 0.010), and lower probability of conversion to general anesthesia (GA, P = 0.027) in MAC group than that in AAA group. Blood gas analysis showed that PetCO2 (P = 0.000), Glu concentration (P = 0.000), and PaCO2 (P = 0.000) were higher, but SPO2 (P = 0.002) and PaO2 (P = 0.000) were lower in MAC group than that in AAA group. In the postoperative recovery stage, compared with that of AAA group, the probability of dysfunction in MAC group at 1, 3, 5, and 7 days after operation was lower, which were 27.8% vs 53.6% (P = 0.003), 31% vs 68.3% (P = 0.000), 28.8% vs 63.4% (P = 0.000), and 25.6% vs 58.5% (P = 0.000), respectively.

CONCLUSION

Compared with AAA, it seems that MAC has more advantages in the management for resection of gliomas in eloquent brain areas, and MAC combined with multiple monitoring such as cerebral cortical mapping, neuronavigation, and ultrasonic detection is worthy of popularization for the resection of gliomas in eloquent brain areas.

Indication and eligibility of glioma patients for awake surgery: A scoping review by a multidisciplinary perspective

Background

Awake surgery (AS) permits intraoperative mapping of cognitive and motor functions, allowing neurosurgeons to tailor the resection according to patient functional boundaries thus preserving long-term patient integrity and maximizing extent of resection. Given the increased risks of the awake scenario, the growing importance of AS in surgical practice favored the debate about patient selection concerning both indication and eligibility criteria. Nonetheless, a systematic investigation is lacking in the literature.

Objective

To provide a scoping review of the literature concerning indication and eligibility criteria for AS in patients with gliomas to answer the questions:1) "What are the functions mostly tested during AS protocols?" and 2) "When and why should a patient be excluded from AS?".

Materials and methods

Pertinent studies were retrieved from PubMed, PsycArticles and Cochrane Central Register of Controlled Trials (CENTRAL), published until April 2021 according to the PRISMA Statement Extension for Scoping Reviews. The retrieved abstracts were checked for the following features being clearly stated: 1) the population described as being composed of glioma(LGG or HGG) patients; 2) the paper had to declare which cognitive or sensorimotor function was tested, or 2bis)the decisional process of inclusion/exclusion for AS had to be described from at least one of the following perspectives: neurosurgical, neurophysiological, anesthesiologic and psychological/neuropsychological.

Results

One hundred and seventy-eight studies stated the functions being tested on 8004 patients. Language is the main indication for AS, even if tasks and stimulation techniques changed over the years. It is followed by monitoring of sensorimotor and visuospatial pathways. This review demonstrated an increasing interest in addressing other superior cognitive functions, such as executive functions and emotions. Forty-five studies on 2645 glioma patients stated the inclusion/exclusion criteria for AS eligibility. Inability to cooperate due to psychological disorder(i.e. anxiety),severe language deficits and other medical conditions(i.e.cardiovascular diseases, obesity, etc.)are widely reported as exclusion criteria for AS. However, a very few papers gave scale exact cut-off. Likewise, age and tumor histology are not standardized parameters for patient selection.

Conclusion

Given the broad spectrum of functions that might be safely and effectively monitored via AS, neurosurgeons and their teams should tailor intraoperative testing on patient needs and background as well as on tumor location and features. Whenever the aforementioned exclusion criteria are not fulfilled, AS should be strongly considered for glioma patients.

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.

Awake craniotomy for auditory brainstem implant in patients with neurofibromatosis type 2: Four case reports

BACKGROUND

The auditory brainstem implant (ABI) is a significant treatment to restore hearing sensations for neurofibromatosis type 2 (NF2) patients. However, there is no ideal method in assisting the placement of ABIs. In this case series, intraoperative cochlear nucleus mapping was performed in awake craniotomy to help guide the placement of the electrode array.

CASE SUMMARY

We applied the asleep-awake-asleep technique for awake craniotomy and hearing test via the retrosigmoid approach for acoustic neuroma resections and ABIs, using mechanical ventilation with a laryngeal mask during the asleep phases, utilizing a ropivacaine-based regional anesthesia, and sevoflurane combined with propofol/remifentanil as the sedative/analgesic agents in four NF2 patients. ABI electrode arrays were placed in the awake phase with successful intraoperative hearing tests in three patients. There was one uncooperative patient whose awake hearing test needed to be aborted. In all cases, tumor resection and ABI were performed safely. Satisfactory electrode effectiveness was achieved in awake ABI placement.

CONCLUSION

This case series suggests that awake craniotomy with an intraoperative hearing test for ABI placement is safe and well tolerated. Awake craniotomy is beneficial for improving the accuracy of ABI electrode placement and meanwhile reduces non-auditory side effects.

Surgery of Insular Diffuse Gliomas-Part 2: Probabilistic Cortico-Subcortical Atlas of Critical Eloquent Brain Structures and Probabilistic Resection Map During Transcortical Awake Resection

BACKGROUND

Insular diffuse glioma surgery is challenging, and tools to help surgical planning could improve the benefit-to-risk ratio.

OBJECTIVE

To provide a probabilistic resection map and frequency atlases of critical eloquent regions of insular diffuse gliomas based on our surgical experience.

METHODS

We computed cortico-subcortical "eloquent" anatomic sites identified intraoperatively by direct electrical stimulations during transcortical awake resection of insular diffuse gliomas in adults.

RESULTS

From 61 insular diffuse gliomas (39 left, 22 right; all left hemispheric dominance for language), we provided a frequency atlas of eloquence of the opercula (left/right; pars orbitalis: 0%/5.0%; pars triangularis: l5.6%/4.5%; pars opercularis: 37.8%/27.3%; precentral gyrus: 97.3%/95.4%; postcentral and supramarginal gyri: 75.0%/57.1%; temporal pole and superior temporal gyrus: 13.3%/0%), which tailored the transcortical approach (frontal operculum to reach the antero-superior insula, temporal operculum to reach the inferior insula, parietal operculum to reach the posterior insula). We provided a frequency atlas of eloquence identifying the subcortical functional boundaries (36.1% pyramidal pathways, 50.8% inferior fronto-occipital fasciculus, 13.1% arcuate and superior longitudinal fasciculi complex, 3.3% somatosensory pathways, 8.2% caudate and lentiform nuclei). Vascular boundaries and increasing errors during testing limited the resection in 8.2% and 11.5% of cases, respectively. We provided a probabilistic 3-dimensional atlas of resectability.

CONCLUSION

Functional mapping under awake conditions has to be performed intraoperatively in each patient to guide surgical approach and resection of insular diffuse gliomas in right and left hemispheres. Frequency atlases of opercula eloquence and of subcortical eloquent anatomic boundaries, and probabilistic 3-dimensional atlas of resectability could guide neurosurgeons.

Return to Work Following Surgery for Incidental Diffuse Low-Grade Glioma: A Prospective Series With 74 Patients

BACKGROUND

Therapeutic strategy concerning incidental low-grade glioma (ILGG) is still debated. Early "prophylactic" surgery has been proposed in asymptomatic patients with favorable neurological and oncological outcomes.

OBJECTIVE

To assess postoperative ability to resume employment following awake surgery in asymptomatic ILGG patients. To assess extent of resection (EOR), timeline for adjuvant oncological treatment, and survival.

METHODS

A total of 74 patients with ILGG who underwent awake surgery with intraoperative mapping were prospectively included, with a minimum follow-up of 12 mo. All clinicoradiological data were collected, and statistical correlations with return to work (RTW) were performed.

RESULTS

A total of 66 patients (97.1%) among 68 patients with preoperative professional activities resumed their employment including 62 (91.2%) within 12 mo. Mean time before RTW was 6.8 mo (median: 6 mo, range: 1-36). Two patients experienced seizure-related legal issues impacting their RTW. Clinicoradiological features did not correlate with RTW apart from postoperative seizures (P = .02). Mean EOR was 95.7%. A total of 43 patients (58.1%) underwent supratotal/total resections. All patients recovered from transient deficits at 3 mo. No patients received consecutive adjuvant treatment. A total of 24 patients (32.4%) were reoperated, 24 patients received chemotherapy, and 7 patients (9.5%) received radiotherapy, on average 73.1 mo after surgery. Mean follow-up was 67 mo (range 12-240). Four patients (5.4%) died during the follow-up.

CONCLUSION

We observed a high rate of RTW (97.1%, including 91.2% within 12 mo) after awake surgery in ILGG patients. Delayed resumption of work was due to employer not clearing them for RTW, personal choice, and, in rare occasions, related to seizures.

Electrophysiological Mapping During Brain Tumor Surgery: Recording Cortical Potentials Evoked Locally, Subcortically and Remotely by Electrical Stimulation to Assess the Brain Connectivity On-line

Direct electrical stimulation (DES) is used to perform functional brain mapping during awake surgery and in epileptic patients. DES may be coupled with the measurement of Evoked Potentials (EP) to study the conductive and integrative properties of activated neural ensembles and probe the spatiotemporal dynamics of short- and long-range networks. However, its electrophysiological effects remain by far unknown. We recorded ECoG signals on two patients undergoing awake brain surgery and measured EP on functional sites after cortical stimulations and were the firsts to record three different types of EP on the same patients. Using low-intensity (1-3 mA) to evoke electrogenesis we observed that: (i) "true" remote EPs are attenuated in amplitude and delayed in time due to the divergence of white matter pathways; (ii) "false" remote EPs are attenuated but not delayed: as they originate from the same electrical source; (iii) Singular but reproducible positive components in the EP can be generated when the DES is applied in the temporal lobe or the premotor cortex; and (iv) rare EP can be triggered when the DES is applied subcortically: these can be either negative, or surprisingly, positive. We proposed different activation and electrophysiological propagation mechanisms following DES, based on the nature of activated neural elements and discussed important methodological pitfalls when measuring EP in the brain. Altogether, these results pave the way to map the connectivity in real-time between the DES and the recording sites; to characterize the local electrophysiological states and to link electrophysiology and function. In the future, and in practice, this technique could be used to perform electrophysiological mapping in order to link (non)-functional to electrophysiological responses with DES and could be used to guide the surgical act itself.

Experience with awake throughout craniotomy in tumour surgery: technique and outcomes of a prospective, consecutive case series with patient perception data

BACKGROUND

Awake craniotomy is the standard of care in surgery of tumours located in eloquent parts of the brain. However, high variability is recorded in multiple parameters, including anaesthetic techniques, mapping paradigms and technology adjuncts. The current study is focused primarily on patients' level of consciousness, surgical technique, and experience based on a cohort of 50 consecutive cases undergoing awake throughout craniotomy (ATC).

METHODS

Data was collected prospectively for 46 patients undergoing 50 operations over 14-month period, by the senior author, including demographics, extent of resection (EOR), adverse intraoperative events, surgical morbidity, surgery duration, levels of O₂ saturation and brain oedema. A prospective, patient experience questionnaire was delivered to 38 patients.

RESULTS

The ATC technique was well tolerated in all patients. Once TCI stopped, all patients were immediately assessable for mapping. Despite > 75% of cases being considered inoperable/high risk, gross total resection (GTR) was achieved in 68% patients and subtotal resection in 20%. The average duration of surgery was 220 min with no episodes of hypoxia. Early and late severe deficits recorded in 12% and 2%, respectively. No stimulation-induced seizures or failed ATCs were recorded. Patient-recorded data showed absent/minimal pain during (1) clamp placement in 95.6% of patients; (2) drilling in 94.7% of patients; (3) surgery in 78.9% of patients. Post-operatively, 92.3% of patients reported willingness to repeat the ATC, if necessary.

CONCLUSIONS

The current ATC paradigm allows immediate brain mapping, maximising patient comfort during self-positioning. Despite the cohort of challenging tumour location, satisfactory EOR was achieved with acceptable morbidity and no adverse intraoperative events.

Result of awake surgery for pediatric eloquent brain area tumors: single-center experience

PURPOSE

About half of brain tumors are located in supratentorial regions and 20% of them in eloquent brain cortex areas. The use of fMRI and intraoperative neuromonitoring allows safe surgery of these areas. Carrying out awake brain surgery (ABS) operations provides additional opportunities for direct-function monitoring. In pediatric practice, this method has not been used widely yet.

METHODS

We present the retrospective analysis of the results of pre-operative examination and surgical treatment of 12 patients with glial tumors located in eloquent cortex areas. Two patients had ABS operations twice. Intraoperative neuromonitoring was used in all the cases.

RESULTS

Twelve patients in total underwent fourteen ABS operations. According to histology results, patients with low-grade tumors prevailed, 11 (91.7%) out of 12. Seven (58.3%) patients had the tumor located in the projection of speech cortex area, four (33.3%) patients in the motor cortex area, and one (8.4%) patient in the visual cortex area. The youngest male was 8 years old. Temporary neurological deficit was diagnosed in three (25%) cases. The tumor was removed completely in 66.7% (eight) cases. Three patients were operated upon twice, two of whom had ABS operations twice. The awake phase of the surgery lasted from 30 to 110 min, 61.2 min on average.

CONCLUSIONS

Our experience has shown sufficient safety of pediatric ABS operations. The achieved functional result and radicality of tumor removal prove that further application and development of this method for children with eloquent brain area tumors (EBATs) is reasonable.

Emergency Airway Management During Awake Craniotomy: Comparison of 5 Techniques in a Cadaveric Model

BACKGROUND

During awake craniotomy, securing the patient's airway might be necessary electively or emergently. The objective of this study was to compare the feasibility of airway management using a laryngeal mask airway (LMA) and 4 alternative airway management techniques in an awake craniotomy simulation.

METHODS

After completing a questionnaire, 9 anesthesia providers attempted airway management in a cadaver positioned to simulate awake craniotomy conditions. Following the simulation, participants rated and ranked the devices in their order of preference.

RESULTS

Only 3 approaches resulted in the successful securement of an airway device for 100% of participants: LMA (median; interquartile range time to secure the airway 6 s, 5 to 10 s), fiberoptic bronchoscopy through an LMA (41 s; 23 to 51 s), and video laryngoscopy (49 s; 43 to 127 s). In contrast, the oral and nasal fiberoptic approaches demonstrated only 44.4% (154.5 s; 134.25 to 182 s) and 55.6% (75 s; 50 to 117 s) success rates, respectively. The LMA was the fastest and most reliable primary method to secure the airway (P=0.001). After the simulation, 100% of participants reported that an LMA would be their first choice for emergency airway management, followed by fiberoptic intubation through the LMA (7 of 9 participants) if the LMA failed to properly seat.

CONCLUSIONS

We demonstrated that an LMA was the fastest and most reliable primary method to secure an airway in a laterally positioned cadaver with 3-pin skull fixation. Fiberoptic and video laryngoscope airway equipment should be readily available during awake craniotomy procedures, and an attempt to visualize the vocal cords through the LMA should be attempted before removing it for alternative techniques.

High-flow nasal cannula improves clinical efficacy of airway management in patients undergoing awake craniotomy

Background

Awake craniotomy requires specific sedation procedure in an awake patient who should be able to cooperate during the intraoperative neurological assessment. Currently, limited number of literatures on the application of high-flow nasal cannula (HFNC) in the anesthetic management for awake craniotomy has been reported. Hence, we carried out a prospective study to assess the safety and efficacy of humidified high-flow nasal cannula (HFNC) airway management in the patients undergoing awake craniotomy.

Methods

Sixty-five patients who underwent awake craniotomy were randomly assigned to use HFNC with oxygen flow rate at 40 L/min or 60 L/min, or nasopharynx airway (NPA) device in the anesthetic management. Data regarding airway management, intraoperative blood gas analysis, intracranial pressure, gastric antral volume, and adverse events were collected and analyzed.

Results

Patients using HFNC with oxygen flow rate at 40 or 60 L/min presented less airway obstruction and injuries. Patients with HFNC 60 L/min maintained longer awake time than the patients with NPA. While the intraoperative PaO₂ and SPO₂ were not significantly different between the HFNC and NPA groups, HFNC patients achieved higher PaO₂/FiO₂ than patients with NPA. There were no differences in Brain Relaxation Score and gastric antral volume among the three groups as well as before and after operation in any of the three groups.

Conclusion

HFNC was safe and effective for the patients during awake craniotomy.

Trial registration

Chinese Clinical Trial Registry, CHiCTR1800016621. Date of Registration: 12 June 2018.

Intraoperative Awakening from Endotracheal General Anesthesia for Brain Mapping with Tracheal Tube In Situ

Awake craniotomy (AC) is indicated to excise a lesion close to an eloquent area of the brain. Success of this procedure depends upon the patient’s active participation during the awake phase of the surgery, especially for brain mapping. Occasionally, a patient may refuse to remain awake during the surgical procedure and demand general anesthesia (GA). A 27-year-old male with uncontrolled seizures from recurrent brain tumor near motor area refused to consent for AC citing his past unpleasant experience; so, the decision to administer GA was taken. To avoid straining/coughing on tracheal tube, his airway was anesthetized with transtracheal xylocaine, bilateral superior laryngeal nerve block, and inflation of tracheal tube cuff with xylocaine. GA was maintained with sevoflurane, infusion of fentanyl, and rocuronium. To awaken him, anesthetics were discontinued and rocuronium antagonized with sugammadex. Intravenous lignocaine and midazolam were administered to supress cough reflex and produce amnesia, respectively. He tolerated the entire duration of 30 minutes of brain mapping with electrocorticography and neurological testing comfortably. Upon completion of brain mapping, GA was reintroduced and the lesion excised. The surgical outcome was good with no neurological deficit. When interviewed postoperatively, the patient had no recall of the awake phase.

Neuropsychological management of the awake patient surgery: A protocol based on 3-year experience with glial tumors

INTRODUCTION

Glial brain tumours usually require neurosurgical treatment and they are associated with cognitive, emotional and behavioural impairments. Awake intraoperative brain mapping is the gold standard technique used to optimize the onco-functional balance. Neuropsychological assessment and intervention have relevance in this type of procedures. Currently, there is a lack of protocolled structure for the neuropsychological intervention being able to satisfy patient needs.

METHOD

A retrospective descriptive study of 52 patients was performed, all of them with a diagnosis of glial tumour. The structure of the protocol developed in our centre is reported, also data of neuropsychological evaluation, comparing baseline performance with both immediate posterior performance, and long term performance.

RESULTS

We describe our experience in each step of the intervention, highlighting the development of eight neurocognitive protocols for intraoperative brain mapping. The results of the neuropsychological examination objectify deficits in the immediate after surgery assessment which are reduced in the long-term assessment.

CONCLUSIONS

We emphasize the need of providing and structuring the cognitive and emotional aspects of patients suffering from any pathology that entails acquired brain damage in hospital environment. This type of approach is aimed at increasing the quality of life of cancer patients by structuring and optimizing tasks during their surgical intervention and attending to the neuropsychological difficulties they suffer.

Successful awake craniotomy in an aged patient with a severe hearing impairment using a bone conduction voice amplifier: a case report

BACKGROUND

The main purposes of awake craniotomy are to minimize postoperative brain dysfunction caused by the surgical procedure and to maximize the tumor resection range. In awake craniotomy, it is important to have a good quality of awakening and to obtain patient's obedience in the awake phase.

CASE PRESENTATION

The patient was a 75-year-old woman with an advanced hearing impairment who was scheduled for awake craniotomy. We used a bone conduction voice amplifier before and during the awake phase and communicated with the patient smoothly.

CONCLUSIONS

We were able to complete awake craniotomy fully, and overcoming the deafness problem might have contributed to the patient's good outcome. This case report indicates that awake craniotomy can be performed in a patient with an advanced hearing impairment under the condition of careful anesthetic management.

Validation of a methodology for neuro-urological and lumbosacral stimulation studies in domestic pigs: a humanlike animal model

OBJECTIVE

Spinal cord injuries (SCIs) result in loss of movement and sensory feedback, but also organ dysfunction. Nearly all patients with complete SCI lose bladder control and are prone to kidney failure if intermittent catheterization is not performed. Electrical stimulation of sacral spinal roots was initially considered to be a promising approach for restoring continence and micturition control, but many patients are discouraged by the need for surgical deafferentation as it could lead to a loss of sensory functions and reflexes. Nevertheless, recent research findings highlight the renewed interest in spinal cord stimulation (SCS). It is thought that synergic recruitment of spinal fibers could be achieved by stimulating the spinal neural networks involved in regulating physiological processes. Paradoxically, most of these recent studies focused on locomotor issues, while few addressed visceral dysfunction. This could at least partially be attributed to the lack of methodological tools. In this study, the authors aim to fill this gap by presenting a comprehensive method for investigating the potential of SCS to restore visceral functions in domestic pigs, a large-animal model considered to be a close approximation to humans.

METHODS

This methodology was tested in 7 female pigs (Landrace pig breed, 45-60 kg, 4 months old) during acute experiments. A combination of morphine and propofol was used for anesthesia when transurethral catheterization and lumbosacral laminectomy (L4-S4) were performed. At the end of the operation, spinal root stimulation (L6-S5) and urodynamic recordings were performed to compare the evoked responses with those observed intraoperatively in humans.

RESULTS

Nervous excitability was preserved despite long-term anesthesia (mean 8.43 ± 1.5 hours). Transurethral catheterization and conventional laminectomy were possible while motor responses (gluteus muscle monitoring) were unaffected throughout the procedure. Consistent detrusor (approximately 25 cm H2O) and sphincter responses were obtained, whereas spinal root stimulation elicited detrusor and external urethral sphincter co-contractions similar to those observed intraoperatively in humans.

CONCLUSIONS

Pigs represent an ideal model for SCS studies aimed at visceral function investigation and restoration because of the close similarities between female domestic pigs and humans, both in terms of anatomical structure and experimental techniques implemented. This article provides methodological keys for conducting experiments with equipment routinely used in clinical practice.

Anesthesia for awake craniotomy

PURPOSE OF REVIEW

The current review reports on current trends in the anesthetic management of awake craniotomy, including preoperative preparation, sedation schemes, pain management, and prevention of intraoperative complications.

RECENT FINDINGS

Both approaches for anesthesia for awake craniotomy, asleep-awake-asleep and monitored anesthesia care (MAC), have shown equal efficacy for performing intraoperative brain mapping. Choice of the appropriate scheme is currently based mainly on the preferences of the particular anesthesiologist. Dexmedetomidine has demonstrated high efficacy and safety in MAC for awake craniotomy and has become a rational alternative to propofol. Despite the high efficacy of scalp block and opioids, pain remains a common compliant in awake craniotomy. Appropriate surgical tactics can reduce pain and even prevent postoperative neurological complications. Although the efficacy of prophylaxis of intraoperative seizures with anticonvulsants remains doubtful, levetiracetam can be superior to other drugs for this purpose.

SUMMARY

Following a great deal of progress in anesthetic management, awake craniotomy, which had been a relatively rare approach, is now a commonly performed procedure for neurosurgical intervention. Modern anesthesia techniques can provide for successful brain mapping in almost any patient. Management of awake craniotomy in high-risk patients is a central task for future research.

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

OBJECTIVEAwake craniotomies have become a feasible tool over time to treat brain tumors located in eloquent regions. Different techniques have been applied in neurooncology centers. Both "asleep-awake-asleep" (asleep) and "conscious sedation" were used subsequently at the authors' neurosurgical department. Since 2013, the authors have only performed conscious sedation surgeries, predominantly using the α2-receptor agonist dexmedetomidine as the anesthetic drug. The aim of this study was to compare both mentioned techniques and evaluate the clinical use of dexmedetomidine in the setting of awake craniotomies for glioma surgery.METHODSThe authors retrospectively analyzed patients who underwent operations either under the asleep condition using propofol-remifentanil or under conscious sedation conditions using dexmedetomidine infusions. In the asleep group patients were intubated with a laryngeal mask and extubated for the assessment period. Adverse events, as well as applied drugs with doses and frequency of usage, were recorded.RESULTSFrom 224 awake surgeries between 2009 and 2015, 180 were performed for the resection of gliomas and included in the study. In the conscious sedation group (n = 75) significantly fewer opiates (p < 0.001) and vasoactive (p < 0.001) and antihypertensive (p < 0.001) drugs were used in comparison with the asleep group (n = 105). Furthermore, the postoperative length of stay (p < 0.001) and the surgical duration (p < 0.001) were significantly lower in the conscious sedation group.CONCLUSIONSUse of dexmedetomidine creates excellent conditions for awake surgeries. It sedates moderately and acts as an anxiolytic. Thus, after ceasing infusion it enables quick and reliable clinical neurological assessment of patients. This might lead to reducing the amount of administered antihypertensive and vasoactive drugs as well as the length of hospitalization, while likely ensuring more rapid surgery.

Awake craniotomy for a cavernous angioma in the Broca’s area

Cavernous angiomas constitute 5%–10% of cerebrovascular malformations and may cause seizure and neurological deficits from bleeding.4 The authors present a case of a 44-year-old man with a 3.5-year history of epilepsy without complete seizure control despite anticonvulsants. Brain MRI showed a 2.8 cm cavernous angioma at the left pars opercularis, also known as the Broca’s area.3 The patient underwent an awake craniotomy for intraoperative cortical–subcortical language and sensory-motor mapping for a complete resection of the cavernous angioma and the hemosiderin rim.1–6 The procedure was uneventful, and the patient evolved seizure free and with no deficits.

The video can be found here: https://youtu.be/QajbLIsr_vg.

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.

Xenon anesthesia for awake craniotomy: safety and efficacy

BACKGROUND

The asleep-awake-asleep (AAA) craniotomy is a technique that offers the opportunity of having a patient fully cooperative during the awake phase, and minimizes the possible discomfort, due to the asleep phase. The aim of this prospective observational study was to test the use of xenon in the first asleep phase of an AAA craniotomy, in patients undergoing craniotomy for brain tumor resection.

METHODS

The data have been collected from 40 awake craniotomy procedures, performed in patients with cerebral tumor, treated with the AAA technique. Patients were treated with xenon during the asleep phase, and quality of mapping, complications and qualitative judgment of the experience given by the patients were recorded.

RESULTS

The mapping was carried out as planned in 37 out of 40 cases. The doses of xenon administered during the first asleep phase of the anesthesia was 13±2 L. Time for awakening after xenon was switched off was 5±1 minute. A combination of xenon and regional anesthesia (with no need for additional systemic anesthetics) was adequate to accomplish craniotomy in 27/40 patients (67.5%). On the day after the operation, 37 patients recalled the testing procedure for mapping during the awake period, none had recollection of local anesthetic injections for regional anesthesia or sound associated with the neurosurgical drill. Five patients (12.5%) reported mild pain during tumor removal (VAS Score less than three).

CONCLUSIONS

In this case series, xenon anesthesia was successfully used for the sedative phase of an awake craniotomy accomplished with an AAA approach.

Awake craniotomy for assisting placement of auditory brainstem implant in NF2 patients

OBJECTIVES

Auditory brainstem implants (ABIs) may be the only opportunity for patients with NF2 to regain some sense of hearing sensation. However, only a very small number of individuals achieved open-set speech understanding and high sentence scores. Suboptimal placement of the ABI electrode array over the cochlear nucleus may be one of main factors for poor auditory performance. In the current study, we present a method of awake craniotomy to assist with ABI placement.

METHODS

Awake surgery and hearing test via the retrosigmoid approach were performed for vestibular schwannoma resections and auditory brainstem implantations in four patients with NF2. Auditory outcomes and complications were assessed postoperatively.

RESULTS

Three of 4 patients who underwent awake craniotomy during ABI surgery received reproducible auditory sensations intraoperatively. Satisfactory numbers of effective electrodes, threshold levels and distinct pitches were achieved in the wake-up hearing test. In addition, relatively few electrodes produced non-auditory percepts. There was no serious complication attributable to the ABI or awake craniotomy.

CONCLUSIONS

It is safe and well tolerated for neurofibromatosis type 2 (NF2) patients using awake craniotomy during auditory brainstem implantation. This method can potentially improve the localization accuracy of the cochlear nucleus during surgery.

Efficacy and safety of dexmedetomidine infusion for patients undergoing awake craniotomy: An observational study

Background:

The goal of awake craniotomy is to maintain adequate sedation, analgesia, respiratory, and hemodynamic stability and also to provide a cooperative patient for neurologic testing. An observational study carried out to evaluate the efficacy of dexmedetomidine sedation for awake craniotomy.

Materials and Methods:

Adult patients with age >18 year who underwent awake craniotomy for intracranial tumor surgery were enrolled. Those who were uncooperative and had difficult airway were excluded from the study. In the operating room, the patients received a bolus dose of dexmedetomidine 1 μg/kg followed by an infusion of 0.2–0.7 μg/kg/h (bispectral index target 60–80). Once the patients were sedated, scalp block was given with bupivacaine 0.25%. The data on hemodynamics at various stages of the procedure, intraoperative complications, total amount of fentanyl used, intravenous fluids required, blood loss and transfusion, duration of surgery, Intensive Care Unit (ICU), and hospital stay were collected. The patients were assessed for Glasgow outcome scale (GOS) score and patient satisfaction score (PSS).

Results:

A total of 27 patients underwent awake craniotomy during a period of 2 years. Most common intraoperative complication was seizures; observed in five patients (18.5%). None of these patients experienced any episode of desaturation. Two patients had tight brain for which propofol boluses were administered. The average fentanyl consumption was 161.5 ± 85.0 μg. The duration of surgery, ICU, and hospital stays were 231.5 ± 90.5 min, 14.5 ± 3.5 h, and 4.7 ± 1.5 days, respectively. The overall PSS was 8 and GOS was good in all the patients.

Conclusion:

The use of dexmedetomidine infusion with regional scalp block in patients undergoing awake craniotomy is safe and efficacious. The absence of major complications and higher PSS makes it close to an ideal agent for craniotomy in awake state.

Awake Craniotomy Anesthesia: A Comparison of the Monitored Anesthesia Care and Asleep-Awake-Asleep Techniques

BACKGROUND

Commonly used sedation techniques for an awake craniotomy include monitored anesthesia care (MAC), using an unprotected airway, and the asleep-awake-asleep (AAA) technique, using a partially or totally protected airway. We present a comparative analysis of the MAC and AAA techniques, evaluating anesthetic management, perioperative outcomes, and complications in a consecutive series of patients undergoing the removal of an eloquent brain lesion.

METHODS

Eighty-one patients underwent awake craniotomy for an intracranial lesion over a 9-year period performed by a single-surgeon and a team of anesthesiologists. Fifty patients were treated using the MAC technique, and 31 were treated using the AAA technique. A retrospective analysis evaluated anesthetic management, intraoperative complications, postoperative outcomes, pain management, and complications.

RESULTS

The MAC and AAA groups had similar preoperative patient and tumor characteristics. Mean operative time was shorter in the MAC group (283.5 minutes vs. 313.3 minutes; P = 0.038). Hypertension was the most common intraoperative complication seen (8% in the MAC group vs. 9.7% in the AAA group; P = 0.794). Intraoperative seizure occurred at a rate of 4% in the MAC group and 3.2% in the AAA group (P = 0.858). Awake cases were converted to general anesthesia in no patients in the MAC group and in 1 patient (3.2%) in the AAA group (P = 0.201). No cases were aborted in either group. The mean hospital length of stay was 3.98 days in the MAC group and 3.84 days in the AAA group (P = 0.833).

CONCLUSIONS

Both the MAC and AAA sedation techniques provide an efficacious and safe method for managing awake craniotomy cases and produce similar perioperative outcomes, with the MAC technique associated with shorter operative time.

The Opioid-Sparing Effect of Perioperative Dexmedetomidine Plus Sufentanil Infusion during Neurosurgery: A Retrospective Study

Background: Approximately 60% of patients experience moderate-to-severe pain after neurosurgery, which primarily occurs in the first 24–72 h. Despite this, improved postoperative analgesia solutions after neurosurgery have not yet been devised. This retrospective study was conducted to evaluate the effect of intra- and post-operative infusions of dexmedetomidine (DEX) plus sufentanil on the quality of postoperative analgesia in patients undergoing neurosurgery.

Methods: One hundred and sixty-three post-neurosurgery patients were divided into two groups: Group D (DEX infusion at 0.5 μg·kg⁻¹ for 10 min, then adjusted to 0.3 μg·kg⁻¹·h⁻¹ until incision suturing) and Group ND (no DEX infusion during surgery). Patient-controlled analgesia was administered for 72 h after surgery (Group D: sufentanil 0.02 μg·kg⁻¹·h⁻¹ plus DEX 0.02 μg·kg⁻¹·h⁻¹, Group ND: sufentanil 0.02 μg·kg⁻¹·h⁻¹) in this retrospective study. The primary outcome measure was postoperative sufentanil consumption. Hemodynamics, requirement of narcotic, and vasoactive drugs, recovery time and the incidence of concerning adverse effects were recorded. Pain intensity [Visual Analogue Scale (VAS)], Ramsay sedation scale (RSS) and Bruggemann comfort scale (BCS) were also evaluated at 1, 4, 8, 12, 24, 48, and 72 h after surgery.

Results: Postoperative sufentanil consumption was significantly lower in Group D during the first 72 h after surgery (P < 0.05). Compared with Group ND, heart rate (HR) in Group D was significantly decreased from intubation to 20 min after arriving at post anesthesia care unit (PACU), while mean arterial pressure (MAP) in Group D was significantly decreased from intubation to 5 min after arriving at PACU (P < 0.05). The intraoperative requirements for sevoflurane, remifentanil, and fentanyl were approximately 35% less in Group D compared with Group ND. VAS at rest at 1, 4, and 8 h and with cough at 12, 24, 48, and 72 h after surgery were significantly lower in Group D (P < 0.05). Compared with Group ND, patients in Group D showed lower levels of overall incidence of tachycardia, hypertension, nausea, and vomiting (P < 0.05). There were no significant differences between the two groups in terms of baseline clinical characteristics, recovery time, RSS, and BCS (P > 0.05).

Conclusions: DEX (0.02 μg·kg⁻¹·h⁻¹) plus sufentanil (0.02 μg·kg⁻¹·h⁻¹) could reduce postoperative opioid consumption and concerning adverse adverse effects, while improving pain scores. However, it did not influence RSS and BCS during the first 72 h after neurosurgery.

Brain tumors in eloquent areas: A European multicenter survey of intraoperative mapping techniques, intraoperative seizures occurrence, and antiepileptic drug prophylaxis

Intraoperative mapping and monitoring techniques for eloquent area tumors are routinely used world wide. Very few data are available regarding mapping and monitoring methods and preferences, intraoperative seizures occurrence and perioperative antiepileptic drug management. A questionnaire was sent to 20 European centers with experience in intraoperative mapping or neurophysiological monitoring for the treatment of eloquent area tumors. Fifteen centers returned the completed questionnaires. Data was available on 2098 patients. 863 patients (41.1%) were operated on through awake surgery and intraoperative mapping, while 1235 patients (58.8%) received asleep surgery and intraoperative electrophysiological monitoring or mapping. There was great heterogeneity between centers with some totally AW oriented (up to 100%) and other almost totally ASL oriented (up to 92%) (31% SD). For awake surgery, 79.9% centers preferred an asleep-awake-asleep anesthesia protocol. Only 53.3% of the centers used ECoG or transcutaneous EEG. The incidence of intraoperative seizures varied significantly between centers, ranging from 2.5% to 54% (p < 0.001). It there appears to be a statistically significant link between the mastery of mapping technique and the risk of intraoperative seizures. Moreover, history of preoperative seizures can significantly increase the risk of intraoperative seizures (p < 0.001). Intraoperative seizures occurrence was similar in patients with or without perioperative drugs (12% vs. 12%, p = 0.2). This is the first European survey to assess intraoperative functional mapping and monitoring protocols and the management of peri- and intraoperative seizures. This data can help identify specific aspects that need to be investigated in prospective and controlled studies.

Hypnosis for Awake Surgery of Low-grade Gliomas: Description of the Method and Psychological Assessment

BACKGROUND

Awake craniotomy with intraoperative electric stimulation is a reliable method for extensive removal of low-grade gliomas while preserving the functional integrity of eloquent surrounding brain structures. Although fully awake procedures have been proposed, asleep-awake-asleep remains the standard technique. Anesthetic contraindications are the only limitation of this method, which is therefore not reliable for older patients with high-grade gliomas.

OBJECTIVE

To describe and assess a novel method for awake craniotomy based on hypnosis.

METHODS

We proposed a novel hypnosedation procedure to patients undergoing awake surgery for low-grade gliomas in our institution between May 2011 and April 2015. Surgical data were retrospectively recorded. The subjective experience of hypnosis was assessed by 3 standardized questionnaires: the Cohen Perceived Stress Scale, the Posttraumatic Stress Disorder Checklist Scale, the Peritraumatic Dissociative Experience Questionnaire, and a fourth questionnaire designed specifically for this study.

RESULTS

Twenty-eight questionnaires were retrieved from 43 procedures performed on 37 patients. The Peritraumatic Dissociative Experience Questionnaire revealed a dissociation state in 17 cases. The Perceived Stress Scale was pathological in 8 patients. Two patients in this group stated that they would not accept a second hypnosedation procedure. The Posttraumatic Stress Disorder Checklist Scale revealed 1 case of posttraumatic stress disorder. Burr hole and bone flap procedures were the most frequently reported unpleasant events during opening (15 of 52 events).

CONCLUSION

The main findings of our study are the effectiveness of the technique, which in all cases allowed resection of the tumor up to functional boundaries, and the positive psychological impact of the technique in most of the patients.

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

BACKGROUND

Awake 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.

METHODS

Two 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].

RESULTS

We 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.

CONCLUSION

SAS 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.