A retrospective analysis of a remifentanil/propofol general anesthetic for craniotomy before awake functional brain mapping

We performed this study to summarize drug dosing, physiologic responses, and anesthetic complications from an IV general anesthetic technique for patients undergoing craniotomy for awake functional brain mapping. Review of 98 procedures revealed "most rapid" IV infusion rates for remifentanil 0.05, 0.05-0.09 microg x kg(-1) x min(-1) and propofol 115, 100-150 microg x kg(-1) x min(-1). The infusions lasted for 78, 58-98 min. Intraoperative emergence from general anesthesia was 9 (6-13) min after discontinuing IV infusions to allow for brain mapping and was independent of infusion duration and duration of craniotomy before mapping. Spontaneous ventilation was generally satisfactory during drug infusion, as evidenced by Sao(2) = 95% (92%-98%) and Paco(2) = 50 (47-55) mm Hg. However, we recorded at least one 30-s epoch of apnea in 69 of 96 patients. Maximum systolic arterial blood pressure was 150 (139-175) mm Hg and minimal systolic arterial blood pressure was 100 (70-150) mm Hg during drug infusion. Three patients experienced intraoperative seizures. Two patients did not tolerate the awake state and required reinduction of general anesthesia. No patients required endotracheal intubation or discontinuation of surgery. This general anesthetic technique is effective for craniotomy with awake functional brain mapping and offers an alternative to continuous wakefulness or other IV sedation techniques. IMPLICATIONS: An IV general anesthetic technique using remifentanil and propofol is an effective method allowing for reliable emergence for intraoperative awake functional brain mapping during craniotomy.     

A Nationwide Questionnaire Survey on Awake Craniotomy in Japan

The number of awake craniotomies is increasing because of its beneficial features. However, not enough information is available regarding the current status of awake craniotomy in Japan. To evaluate the current status of awake craniotomy in institutes, a nationwide questionnaire survey was conducted. From June to August 2019, we conducted a questionnaire survey on awake craniotomy in the neurosurgery department of 45 institutes that perform awake craniotomies in Japan. Responses were obtained from 39 institutes (response rate, 86.7%). The main methods of awake craniotomy were almost the same in all institutes. Twenty-six institutes (66.7%) had fewer than 10 awake craniotomies (low-volume institutes) per year, and 13 high-volume institutes (33.3%) performed more than 10 awake craniotomies annually. Some institutes experienced a relatively high frequency of adverse events. In 11 institutes (28.2%), the frequency of intraoperative seizures was more than 10%. An intraoperative seizure frequency of 1%-9%, 10%-29%, and over 30% was identified in 12 (92%), 0 (0%), and 1 (8%) of the high-volume institutes, which was significantly less than in 16 (62%), 10 (38%), and 0 (0%) of the low-volume institutes (p = 0.0059). The routine usage of preoperative antiepileptic drugs was not different between them, but the old type was used more often in the low-volume institutes (p = 0.0022). Taken together, the annual number of awake craniotomies was less than 10 in over two-thirds of the institutes. Fewer intraoperative seizures were reported in the high-volume institutes, which tend not to preoperatively use the old type of antiepileptic drugs.     

Anesthetic complications of awake craniotomies for epilepsy surgery

Awake craniotomies are often performed for resection of epileptogenic foci close to vital areas of the brain. For awake craniotomies at our institution, propofol is infused during local anesthetic injection and craniotomy, spontaneous ventilation is preserved, and no endotracheal tube or laryngeal mask airway is used. Propofol is discontinued for language, motor, and/or sensory mapping and for electrocorticography. Patients are re-sedated with propofol for resection and closure. We performed a retrospective chart review of 332 propofol-based "asleep-awake-asleep" (AAA) techniques with unsecured airways and 129 general anesthesia with endotracheal intubation craniotomies for epilepsy surgery. We compared the incidence of intraoperative respiratory and hemodynamic complications and incidence of seizures, nausea, brain swelling, patient movement, bleeding, aspiration, air embolism, and death. Airway compromise was uncommon in AAA cases and although incidences of hypertension, hypotension, and tachycardia were statistically increased in AAA versus general anesthesia craniotomy, these were treated appropriately. In only one patient the use of our AAA technique may have contributed to a poor clinical outcome.     

Use of the laryngeal mask airway during awake craniotomy for tumor resection

There is an increasing trend toward performing craniotomy for primary brain tumor excision with local anesthesia. We report the use of the laryngeal mask airway as a part of an anesthetic technique designed for patients requiring awake cortical mapping during brain tumor excision.     

Prospective study of awake craniotomy used routinely and nonselectively for supratentorial tumors

OBJECT: The authors prospectively assessed the value of awake craniotomy used nonselectively in patients undergoing resection of supratentorial tumors. METHODS: The demographic features, presenting symptoms, tumor location, histological diagnosis, outcomes, and complications were documented for 610 patients who underwent awake craniotomy for supratentorial tumor resection. Intraoperative brain mapping was used in 511 cases (83.8%). Mapping identified eloquent cortex in 115 patients (22.5%) and no eloquent cortex in 396 patients (77.5%). RESULTS: Neurological deficits occurred in 89 patients (14.6%). In the subset of 511 patients in whom brain mapping was performed, 78 (15.3%) experienced postoperative neurological worsening. This phenomenon was more common in patients with preoperative neurological deficits or in those individuals in whom mapping successfully identified eloquent tissue. Twenty-five (4.9%) of the 511 patients suffered intraoperative seizures, and two of these individuals required intubation and induction of general anesthesia after generalized seizures occurred. Four (0.7%) of the 610 patients developed wound complications. Postoperative hematomas developed in seven patients (1.1%), four of whom urgently required a repeated craniotomy to allow evacuation of the clot. Two patients (0.3%) required readmission to the hospital soon after being discharged. There were three deaths (0.5%). CONCLUSIONS: Awake craniotomy is safe, practical, and effective during resection of supratentorial lesions of diverse pathological range and location. It allows for intraoperative brain mapping that helps identify and protect functional cortex. It also avoids the complications inherent in the induction of general anesthesia. Awake craniotomy provides an excellent alternative to surgery of supratentorial brain lesions in patients in whom general anesthesia has been induced.     

Awake craniotomy for removal of intracranial tumor: considerations for early discharge

We retrospectively reviewed the anesthetic management, complications, and discharge time of 241 patients undergoing awake craniotomy for removal of intracranial tumor to determine the feasibility of early discharge. The results were analyzed by using univariate analysis of variance and multiple logistic regression. The median length of stay for inpatients was 4 days. Fifteen patients (6%) were discharged 6 h after surgery and 76 patients (31%) were discharged on the next day. Anesthesia was provided by using local infiltration supplemented with neurolept anesthesia consisting of midazolam, fentanyl, and propofol. There was no significant difference in the total amount of sedation required. Overall, anesthetic complications were minimal. One patient (0.4%) required conversion to general anesthesia and one patient developed a venous air embolus. Fifteen patients (6%) had self-limiting intraoperative seizures that were short-lived. Of the 16 patients scheduled for ambulatory surgery, there was one readmission and one unanticipated admission. It may be feasible to discharge patients on the same or the next day after awake craniotomy for removal of intracranial tumor. However, caution is advised and patient selection must be stringent with regards to the preoperative functional status of the patient, tumor depth, surrounding edema, patient support at home, and ease of access to hospital for readmission. Implications: It may be feasible to perform awake craniotomies for removal of intracranial tumor as an ambulatory procedure; however, caution is advised. Patient selection must be stringent with respect to the patient's preoperative functional status, tumor depth, surrounding edema, patient support at home, and ease of access to hospital for readmission.     

Awake craniotomy using dexmedetomidine and scalp blocks: a retrospective cohort study

Purpose

Anesthetic and surgical considerations for awake craniotomy (AC) include airway patency, patient comfort, and optimization of real-time brain mapping. The purpose of this study is to report our experience of using dexmedetomidine and scalp blocks, without airway intervention, as a means to facilitate and optimize intraoperative brain mapping and brain tumour resection during AC.

Methods

We conducted a retrospective cohort study of 55 patients who underwent AC from March 2012 to September 2016. The incidence of critical airway outcomes, perioperative complications, and successful intraoperative mapping was determined. The primary outcome was the incidence of a failed AC anesthetic technique as defined by the need to convert to general anesthesia with a secured airway prior to (or during) brain mapping and brain tumour resection. Secondary outcomes were the intraoperative incidence of: 1) altered surgical management due to information acquired through real-time brain mapping, 2) interventions to restore airway patency or rescue the airway, 3) hemodynamic instability (> 20% from baseline), 4) nausea and vomiting, 5) new onset neurologic deficits, and 6) seizure activity.

Results

There were no anesthesia-related critical events and no patients required airway manipulation or conversion to a general anesthetic. Multimodal language, motor, and sensory assessment with direct cortical electrical stimulation was successfully performed in 100% of cases. In 24% (13/55) of patients, data acquired during intraoperative brain mapping influenced surgical decision-making regarding the extent of tumour resection. Nine (16%) patients had intraoperative seizures.

Conclusions

Dexmedetomidine-based anesthesia and scalp block facilitated AC surgery without any requirement for urgent airway intervention or unplanned conversion to a full general anesthetic. This approach can enable physiologic testing before and during tumour resection facilitating real-time surgical decision-making based on intraoperative brain mapping with patients awake thereby minimizing the risk of neurologic deficit and increasing the opportunity for optimal surgical resection.

     

Management of anesthesia in awake craniotomy

The awake craniotomy technique was originally introduced for the surgical treatment of epilepsy and has subsequently been used in patients undergoing surgical management of supratentorial tumors, arteriovenous malformation, deep brain stimulation, and mycotic aneurysms near critical brain regions. This surgical approach aims to maximize lesion resection while sparing important areas of the brain (motor, somatosensory, and language areas). Awake craniotomy offers great advantages with respect to patient outcome. In this type of procedure, the anesthetist's goal is to make the operation safe and effective and reduce the psychophysical distress of the patient. Many authors have described different anesthetic care protocols for awake craniotomy based on monitored or general anesthesia; however, there is still no consensus as to the best anesthetic technique. The most commonly used drugs for awake craniotomies are propofol and remifentanil, but dexmedetomidine is beginning to be used more commonly outside of Europe. Personal experience, careful planning, and attention to detail are the basis for obtaining good awake craniotomy RESULTS: Additional studies are necessary in order to optimize the procedure, reduce complications, and improve patient tolerance. The aim of this review is to present a thorough report of the literature, with particular attention to neuro-oncology surgery.     

Dexmedetomidine sedation during awake craniotomy for seizure resection: effects on electrocorticography

Patients with refractory seizures may undergo awake craniotomy and cortical resection of the seizure area, using intraoperative functional mapping and electrocorticography (ECoG). We used dexmedetomidine in 6 patients, transitioning successively from the asleep-awake-asleep method, through a combined propofol/dexmedetomidine sedative infusion, to dexmedetomidine as the only sedation. Initial experience with the asleep-awake-asleep method in 2 patients was successful with the replacement of propofol/laryngeal mask anesthesia, 20 to 30 minutes before ECoG testing, by dexmedetomidine infusion, maintained at 0.2 mcg kg-1 h-1 throughout neurocognitive testing. Propofol anesthesia was reintroduced for resection. One patient received combined dexmedetomidine (0.2 mcg kg-1 h-1) and propofol (200 mcg kg-1 min-1) infusions for sedation. Both infusions were stopped 15 minutes before ECoG. Subsequently, they were restarted and the epileptic foci resected. Three patients received dexmedetomidine as the sole sedative agent, together with scalp block local anesthesia, and incremental boluses totaling 150 to 175 mcg of fentanyl per case. Dexmedetomidine was started with 0.3 mcg kg-1 boluses and maintained with 0.2 to 0.7 mcg kg-1 h-1for craniotomy, testing, and resection. The infusion was paused for 20 minutes in 1 patient to allow improvement in neurocognitive testing. This occurred within 10 minutes. All patients enjoyed good hemodynamic control, with blood pressure maintained within 20% of initial values, and made uneventful recoveries. The surgical conditions were all reported as favorable. Dexmedetomidine can be used singly for sedation in awake craniotomy requiring ECoG. Individual dose ranges vary, but a bolus of 0.3 mcg kg-1 with an infusion of 0.2 mcg kg-1 min-1 is a good starting point, allowing accurate mapping of epileptic foci and subsequent resection.     

The laryngeal mask airway for awake craniotomy in the pediatric patient: report of three cases

The anesthetic management of three pediatric patients who underwent awake craniotomy with a combined, continuous intravenous infusion of propofol and alfentanil is described. The Laryngeal Mask Airway was effective in airway management during resection of epileptic foci with intraoperative cortical mapping and neuropsychological (speech) evaluation.     

Use of dexmedetomidine in awake craniotomy in adolescents: report of two cases

Awake craniotomy is a key tool in resection of lesions near critical functional regions, particularly the speech area. Craniotomy with an awake portion for mapping may be performed in carefully selected adolescents and preteenaged children. A number of different regimens may be used for sedation and anesthesia in these cases. We describe two adolescent patients in whom awake craniotomy was performed using an intravenous anesthesia technique with dexmedetomidine and without need for airway instrumentation.     

右美托咪定在功能神经外科的围手术期应用进展

右美托咪定（dexmedetomidine, Dex）是一种α 2肾上腺素能受体激动剂,其镇静过程接近于自然睡眠,易于唤醒,同时具有镇痛、抑制交感神经活性、无明显呼吸抑制等特性。功能神经外科手术中进行的电生理功能监测对于定位手术区域和决定手术能否成功至关重要。目前证据表明低剂量Dex不干扰电生理监测,适用于神...     

Anesthesia for functional neurosurgery: review of complications

The use of functional stereotactic neurosurgery is increasing for treatment of patients with movement disorders and other chronic illnesses. The anesthetic considerations include the influence of the anesthetic agents on the microelectrode recordings and stimulation testing of an awake patient. The purpose of this study was to review the anesthetic management and incidences of intraoperative complications during functional neurosurgery in our institution. One hundred seventy-eight patients underwent an ablative procedure (n = 6) or the insertion of deep brain stimulator (n = 172) under monitored anesthesia care for movement disorders (n = 124), chronic pain (n = 20), and other procedures (n = 34). Local anesthetic was used for head frame pin sites and burr holes. No sedation/analgesia was administered to 57 (32%) patients. One patient required conscious sedation and another general anesthesia for the entire procedure. The remainder received small increments (mean +/- SD) of propofol (113 +/- 73 mg), midazolam (1.6 +/- 0.8 mg), and/or fentanyl (93 +/- 55 mug). Intraoperative complications that occurred in 16% of the patients included seizures (n = 8), change in neurologic status (n = 5), airway obstruction (n = 2), and hypertension (n = 7). Functional neurosurgery can be performed with minimal anesthesia in many patients. Awareness and vigilance can improve the identification and early treatment of intraoperative complications such as seizures, loss of airway, and changes in the neurologic status.     

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.     

Dexmedetomidine as rescue drug during awake craniotomy for cortical motor mapping and tumor resection

Dexmedetomidine, approved for providing sedation in the critical care environment, is also used during awake craniotomies to facilitate procedures such as cortical mapping. Herein, we describe the use of dexmedetomidine as a rescue drug during awake craniotomy avoiding conversion to general anesthesia, thus allowing completion of cortical mapping.     

The history of awake craniotomy for brain tumor and its spread into Asia

In ancient times, awake craniotomy was used for trepanation to treat seizures and remove a variety of morbid conditions or even to permit the escape of evil air. In modern times, this technique was initially used for removal of epileptic foci with simultaneous application of brain mapping with electrical current. Further developments brought this technique into use for resection of tumors involving functional cortex. Recently, awake craniotomy has been described as an approach for removal of supratentorial tumors nonselectively, regardless of the involvement of eloquent cortex. It has been used in North America since the 1980s, then Europe, and recently has spread into Asia. Its spread to Asia could have significant impact based on the large population of patients and the low resource utilization associated with awake craniotomy.     

Preoperative Prediction of Communication Difficulties during Awake Craniotomy in Glioma Patients: A Retrospective Evaluation of 136 Cases at a Single Institution

Awake craniotomy has been widely performed in patients with glioma in eloquent areas to minimize postoperative brain dysfunction. However, neurological examination in awake craniotomy is sometimes problematic due to communication difficulties during the intraoperative awake period. We evaluated preoperative predictors of these difficulties in awake craniotomy for patients with glioma. In all, 136 patients with glioma who underwent awake craniotomy at our institution between January 2012 and January 2020 were retrospectively evaluated. Patients were divided into two groups (appropriately awake group and inappropriately awake group) depending on their state during the intraoperative awake period, and the relationship between communication difficulties in awake craniotomy and both clinical and radiological characteristics were assessed. The appropriately awake group included 110 patients, and the inappropriately awake group included 26 patients. Reasons for inclusion in the inappropriately awake group were insufficient wakefulness in 15 patients, restless state in 6, and intraoperative seizures in 5. In multivariate analysis, the likelihood of being inappropriately awake was inversely correlated with preoperative seizures (odds ratio [OR], 0.23; 95% confidence interval [CI], 0.06–0.89; p = 0.033) and positively correlated with left-sided lesions (OR, 7.31; 95% CI, 1.54–34.62; p = 0.012). Both lack of preoperative seizures and left-sided lesions were identified as risk factors for intraoperative difficulties in awake craniotomy for patients with glioma. Understanding these risk factors may lead to more appropriate determination of eligibility for awake craniotomy.     

Awake craniotomy using initial sleep with laryngeal mask airway in depressed agitated patient--a case report

Depressed patients with brain tumors are often not referred to awake craniotomy because of concern of uncooperation which may increase the risk of perioperative complications. This report describes an interesting case of Awake Craniotomy for frontal lobe glioma in 41 year old woman undergoing language and motor mapping intra-operatively. As she was fearful and apprehensive and was on antidepressant therapy to control depression the author adapted general anesthesia with laryngeal mask airway during initial stage of skull pinning and craniotomy procedures. Then patient reverted to awake state to continue the intended neurosurgical procedure. Patient tolerated the situation satisfactory and was cooperative till the finish without any event.