Risk Factors and Characteristics of Intraoperative Seizures During Awake Craniotomy: A Retrospective Cohort Study of 562 Consecutive Patients With a Space-occupying Brain Lesion

Intraoperative Seizures During Awake Craniotomy for Brain Tumor Resection

Background Intra-operative seizures (IOS) can occur during awake craniotomies (AC) for brain tumors. They can potentially result in an increased risk of morbidity; however, literature is scarce on IOS, its risk factors, and predictors. This study aims to ascertain the frequency of IOS in patients undergoing AC and determine possible IOS predictors. Methods In this retrospective study, we reviewed the records of all patients who underwent AC for tumor resection at a single university hospital between January 2016 and December 2020. IOS was defined as any seizure, including partial or generalized, experienced by any patient at any time from the beginning of the procedure till the end of surgery. Results Two hundred patients underwent AC during the study period. Seven (3.5%) patients experienced IOS. Compared to the non-seizure group, no significant correlation existed with any demographic variable. No significant difference was seen between the initial complaints presented by the two groups. In addition, the post-operative course of the seizure group did not significantly differ from the non-seizure group. Due to the low frequency of IOS in our cohort, an extensive analysis to determine predictors could not be performed. Conclusion In this study, we observed a low frequency of IOS (3.5%) during AC. The possible predictors and risk factors must be further investigated in large cohorts; to help limit the consequences of this possible intraoperative complication.

Case report of epileptic seizure during awake craniotomy of functional area glioma and literature study

Intraoperative seizure is the most prevalent and serious complication of awake craniotomy in functional areas, which may not only trigger complications of the surgical procedure or even the failure of awake craniotomy but also may result in adverse consequences to patients. The influencing factors of intraoperative seizures are unclear, and only the possible influencing factors can be acquired from the examination and summary of existing cases to offer guidance for the seizure prevention of intraoperative epilepsy.

Risk factors and predictors of intraoperative seizures during awake craniotomy: A systematic review and meta-analysis

Background

Awake craniotomy (AC) aims to minimize postoperative neurological complications while allowing maximum safe resection. Intraoperative seizures (IOSs) have been a reported complication during AC; however, literature delving into the predictors of IOS remains limited. Therefore, we planned a systematic review and meta-analysis of existing literature to explore predictors of IOS during AC.

Methods

From the inception until June 1, 2022, systematic searches of PubMed, Scopus, the Cochrane Library, CINAHL, and Cochrane's Central Register of Controlled Trials were conducted to look for published studies reporting IOS predictors during AC.

Results

We found 83 different studies in total; included were six studies with a total of 1815 patients, and 8.4% of them experienced IOSs. The mean age of included patients was 45.3 years, and 38% of the sample was female. Glioma was the most common diagnosis among the patients. A pooled random effect odds ratio (OR) of frontal lobe lesions was 2.42 (95% confidence intervals [CI]: 1.10-5.33, P = 0.03). Those with a pre-existing history of seizures had an OR of 1.80 (95% CI: 1.13-2.87, P = 0.01), and patients on antiepileptic drugs (AEDs) had a pooled OR of 2.47 (95% CI: 1.59-3.85, P < 0.001).

Conclusion

Patients with lesions of the frontal lobe, a prior history of seizures, and patients on AEDs are at higher risk of IOSs. These factors should be taken into consideration during the patient's preparation for an AC to avoid an intractable seizure and consequently a failed AC.

Effect of Dexmedetomidine versus Propofol on Intraoperative Seizure Onset During Awake Craniotomy: A Retrospective Study

OBJECTIVE

The effect of dexmedetomidine (DEX) compared with propofol on intraoperative seizures (IOSs) detected using electrocorticography during awake craniotomy for resection of brain tumors is unknown. This investigation aimed to compare IOS rate in patients receiving DEX versus propofol as sedative agent.

METHODS

In this retrospective single-center study, awake craniotomies performed from January 2014 to December 2019 were analyzed. All IOSs detected by electrocorticography along with vital signs were recorded.

RESULTS

Of 168 adults enrolled in the study, 58 were administered DEX and 110 were administered propofol. IOSs occurred more frequently in the DEX group (22%) versus the propofol group (11%) (P = 0.046). A higher incidence of bradycardia was also observed in the DEX group (P < 0.001). Higher incidence of hypertension and a higher mean heart rate were recorded in the propofol group (P = 0.006 and P < 0.001, respectively). No serious adverse events requiring active drug administration were noted in either group. At univariate regression analysis, DEX demonstrated a tendency to favor IOS onset but without statistical significance (odds ratio = 2.36, P = 0.051). Patients in both groups had a similar epilepsy outcome at the 1-year postoperative follow-up.

CONCLUSIONS

IOSs detected with electrocorticography during awake craniotomy occurred more frequently in patients receiving DEX than propofol. However, patients receiving DEX were not shown to be at a statistically significant greater risk for IOS onset. DEX is a valid alternative to propofol during awake craniotomy in patients affected by tumor-related epilepsy.

Tolerability of Repeat Awake Craniotomy: A Propensity-Score-Matched Analysis on 607 Consecutive Cases

BACKGROUND

Awake craniotomy is used for addressing lesions adjacent to eloquent brain regions to minimize damage to neurological functions, and to expedite postoperative recovery. Redo (i.e., repeat) awake surgery is not common, but always an option, especially for recurrent tumors. This study investigated the tolerability of redo awake surgery in terms of surgical characteristics and postoperative clinical course.

METHODS

Single-institution cohort study of 607 awake craniotomies by 1 surgeon at Toronto Western Hospital, 2006-2018.

RESULTS

Out of 607 surgeries, 501 surgeries were first-time, and 106 surgeries were redo. Between the 2 groups, surgery time was longer in redo cases than first-time cases and the rate of reoperation was higher in the former. Matched propensity cohort analysis included 104 cases each, based on adjustments for age, sex, tumor location, malignancy, and preoperative performance status. This revealed differences again in surgery time (128.0 vs. 111.9 minutes, P = 0.0004) and the reoperation rate (7.4 vs. 1.0%, P = 0.03). The causes of reoperation were infection (3 wound infection and 3 brain abscess) and wound dehiscence (n = 1). There was no significant difference in the length of hospital stay, the rates of postoperative hemorrhage, new postoperative neurological deficits, home discharge, or readmission.

CONCLUSIONS

Although redo surgery might increase the surgery time and the risk of reoperation due to postoperative infection, it was found to be well tolerated in other aspects overall. With extra care to infection and wound healing, redo awake surgery is a viable option to patients with the same surgical indication as for first-time surgery.

Comparison of Monitored Anesthesia Care with Propofol Versus Dexmedetomidine for Awake Craniotomy: A Retrospective study

Background Anesthetic agents used for awake craniotomy should be safe, short-acting, titratable, and provide an adequate level of sedation and analgesia, along with facilitating adequate neurological assessment during the functional testing. Our study aims to review the efficacy and safety profile, along with the potential for neurophysiological monitoring, of two commonly used anesthetic regimens, i.e., propofol and dexmedetomidine.

Methods After the Ethics Committee approval, a retrospective analysis of 51 patients who underwent awake craniotomy for brain tumor excision over a period of 7 years was done. Those who received monitored anesthesia care (MAC) were divided into two groups, namely, Group P for that received propofol, and Group D that received dexmedetomidine and their hemodynamic profile, perioperative complications, neuromonitoring techniques, and postoperative course was noted from the records.

Results A total of 31 patients were administered MAC with propofol and 20 with dexmedetomidine. The baseline demographic data, duration of surgery, intensive care unit (ICU), and hospital stay were comparable between the two. The hemodynamic profile as assessed by the heart rate and blood pressure was also comparable. The incidence of intraoperative seizures was found to be less in Group P, though. Episodes of transient desaturation were observed more in Group P (9.7%) than in Group D (5%), but none of the patients required conversion to general anesthesia. Direct cortical stimulation was satisfactorily elicited in 80% in Group P and 85% in Group D.

Conclusions MAC with propofol and dexmedetomidine are acceptable techniques with comparable hemodynamic profile, intraoperative and postoperative complications, and potential for neurophysiological monitoring.

Benzodiazepine Sedation and Postoperative Neurological Deficits after Awake Craniotomy for Brain Tumor - An Exploratory Retrospective Cohort Study

An awake craniotomy is a common neurosurgical procedure for excising brain tumor(s) located near or in eloquent areas. The use of benzodiazepine (BZD) for sedation in some patients with neuropathological conditions (e.g., stroke, brain tumors) has been previously linked with re-appearance of neurological deficits including limb incoordination, ataxia, and motor weakness, resulting in complications for the patient along with procedural challenges. Whether or not these findings can be extrapolated to patients undergoing brain tumor resection is largely unknown. The current work primarily sought to compare neurological outcome(s) in the immediate postoperative period between BZD-free and BZD-based sedation techniques in patients undergoing awake craniotomy. Using a database composed of awake craniotomies conducted within a single center and by a single surgeon, patients were retrospectively classified based on midazolam administration into BZD-free sedation (n=125) and BZD-based sedation (n=416) groups. Patients from each group were matched based on age, sex, tumor location, tumor grade, preoperative neurological deficits, non-operative BZD use, and Karnofsky Performance Scale scores, resulting in 108 patients within each group. Postoperative neurological deficits were recorded. Logistic regression analyses were conducted comparing postoperative neurological deficits between the matched groups. Postoperative neurological deficits were more prevalent within the BZD-based sedation group compared to the BZD-free sedation group (adjusted odds ratio (aOR)=1.903, 95% CI=1.018-3.560, p=0.044). In addition, subgroup analysis of the matched cohort showed a relationship between preoperative neurological symptoms and postoperative neurological deficits in the BZD-based sedation group (aOR=3.756, 95% CI=1.390-10.147, p=0.009). Our findings support the notion that the increased incidence of postoperative neurological deficits with BZD sedation may in part be related to the unmasking of preoperative neurological deficits. Further studies are required to confirm this phenomenon.