Startle sign events induced by mechanical manipulation during surgery for neuroma localization: a retrospective cohort study.

BACKGROUND: Chronic pain from peripheral neuromas is difficult to manage and often requires surgical excision, though intraoperative identification of neuromas can be challenging due to anatomical ambiguity. Mechanical manipulation of the neuroma during surgery can elicit a characteristic "startle sign", which can help guide surgical management. However, it is unknown how anesthetic management affects detection of the startle sign. METHODS: We performed a retrospective cohort study of 73 neuroma excision surgeries performed recently at Massachusetts General Hospital. Physiological changes in the anesthetic record were analyzed to identify associations with a startle sign event. Anesthesia type and doses of pharmacological agents were analyzed between startle sign and no-startle sign groups. RESULTS: Of the 64 neuroma resection surgeries included, 13 had a startle sign. Combined intravenous and inhalation anesthesia (CIVIA) was more frequently used in the startle sign group vs. no-startle sign group (54% vs. 8%), while regional blockade with monitored anesthetic care was not associated with the startle sign group (12% vs. 0%), p = 0.001 for anesthesia type. Other factors, such as neuromuscular blocking agents, ketamine infusion, remifentanil infusion, and intravenous morphine equivalents showed no differences between groups. CONCLUSIONS: Here, we identified hypothesis-generating descriptive differences in anesthetic management associated with the detection of the neuroma startle sign during neuroma excision surgery, suggesting ways to deliver anesthesia facilitating detection of this phenomenon. Prospective trials are needed to further validate the hypotheses generated.

The Performance of Continuous Glucose Monitoring During the Intraoperative Period: A Scoping Review.

Introduction: Perioperative dysglycemia is associated with negative surgical outcomes, including increased risk of infections and longer hospital stays. Continuous glucose monitoring (CGM) provides real-time glucose data, potentially improving glycemic control during surgery. However, the performance of CGM in the intraoperative environment has not been well established. This scoping review aimed to evaluate the performance of CGM systems during the intraoperative period, focusing on their technical reliability, accuracy, adverse device effects, and efficacy. Inclusion criteria: Studies that assessed intraoperative CGM performance, focusing on technical reliability, accuracy, adverse effects, or efficacy, were included. No restrictions were placed on the study design, surgical type, participant demographics, or publication date. Methods: A comprehensive literature search was performed using PubMed, EMBASE, and the Cochrane Library, covering publications up to 12 June 2024. Two independent reviewers screened and selected the studies for inclusion based on predefined eligibility criteria. Data extraction focused on the study characteristics, CGM performance, and outcomes. Results: Twenty-two studies were included, the majority of which were prospective cohort studies. CGM systems demonstrated a high technical reliability, with sensor survival rates above 80%. However, the accuracy varied, with some studies reporting mean or median absolute relative differences of over 15%. The adverse effects were minimal and mainly involved minor skin irritation. One randomized trial found no significant difference between CGM and point-of-care glucose monitoring for glycemic control. Conclusions: Although CGM has the potential to improve intraoperative glycemic management, its accuracy remains inconsistent. Future research should explore newer CGM technologies and assess their impact on surgical outcomes.

Methodology for Measuring Intraoperative Blood Loss: Protocol for a Scoping Review.

BACKGROUND: At present, there is no standardized method for measuring intraoperative blood loss. Rather, the current data on existing methods is very broad and opaque. In many cases, blood loss during surgery is estimated visually by the surgeon. However, it is known that this type of method is very prone to error. Therefore, better standardized methods are needed. OBJECTIVE: This study aims to conduct a scoping review to present the currently available methods for measuring intraoperative blood loss. This should help to capture the current status and map and summarize the available evidence for measuring blood loss to identify any gaps. METHODS: We will use a state-of-the-art methodological framework. The databases PubMed (MEDLINE) and Cochrane Library will be searched using a search strategy based on the PICO (Population, Intervention, Comparator, and Outcome) scheme. The search period will be limited to January 01, 2012, to December 31, 2023, and our search will be restricted to clinical trials or clinical studies, randomized controlled trials, and observational studies (in line with PubMed definition of study types). Only publications in English and German will be considered. The intention is to identify clinical studies that define "blood loss" as a target criterion or as a primary or secondary end point. EndNote (version 20.6; Clarivate) will be used for the screening process. The data will be collected and analyzed using Microsoft Excel (version 16.77.1). RESULTS: The included studies will be listed in a database, and the following basic data will be extracted: title, year of publication, country, language, study type, surgical specialty, and type of procedure. The number of participants will be listed and the distribution of the participants will be documented in terms of gender and age. The following results are extracted: the type of measurement method used to measure blood loss in this study and whether the parameter "blood loss" was recorded as a primary or secondary outcome. CONCLUSIONS: Currently, there is no comparable review, resulting in ambiguous data regarding the prevailing measurement methods for intraoperative blood loss. The aim of this study is to provide a comprehensive overview-from methods of measurement to various formulae for calculating blood loss-and to establish a status quo. This could then serve as a foundation for further studies. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/58022.

Time varying characteristic in somatosensory evoked potentials as a biomarker of spinal cord ischemic-reperfusion injury in rat.

Spinal cord ischemic-reperfusion injury (SCIRI) could occurs during surgical procedures without detection, presenting a complex course and an unfavorable prognosis. This may lead to postoperative sensory or motor dysfunction in areas innervated by the spinal cord, and in some cases, permanent paralysis. Timely detection of SCIRI and immediate waring can help surgeons implement remedial intervention to prevent irreversible spinal cord injury. Therefore, it is crucial to develop a precise and effective method for early detection of SCIRI. This study utilized rat models to simulate intraoperative SCIRI and employed somatosensory evoked potentials (SEP) for continuous monitoring during surgery. In this study, SEP signal changes were examined in six groups with varying severities of SCIRI and one normal control group. SEP signal changes were examined during operations in different groups and correlated with postoperative behavioral and histopathological data. The result demonstrated specific changes in SEP signals during SCIRI, termed as time-varying characteristics, which are associated with the duration of ischemia and subsequent reperfusion. Time-varying characteristics in SEP could potentially serve as a new biomarker for the intraoperative detection of SCIRI. This finding is significant for clinical surgeons to identify and guide early intervention of SCIRI timely. Additionally, this measurement is easily translatable to clinical application.

Comparative Efficacy of Intraoperative Patient State Index vs. Bi-Spectral Index in Patients Undergoing Elective Spine Surgery with Neuromonitoring Under General Anaesthesia: A Randomized Controlled Trial.

Objective: Various electroencephalogram-based monitors have been introduced to objectively quantify anaesthesia depth. However, limited data are available on their comparative clinical efficacy in various surgical procedures. Therefore, we planned this study to compare the relative efficacy of patient state index (PSI) vs. Bi-spectral index (BIS) assessment in patients undergoing elective spine surgery under general anaesthesia. Methods: This prospective, parallel-group, single-center study included patients undergoing major spine surgery with neuromonitoring. Patients were randomized into two groups, i.e., group B (undergoing surgery under BIS monitoring) and group P (undergoing surgery under PSI monitoring). The primary objective was to compare the time to eye opening after stopping anaesthetic drug infusions. Results: The mean propofol dose required for induction in group B was 130.45±26.579, whereas that in group P, it was 139.28±17.86 (P value 0.085). The maintenance doses of propofol and fentanyl required for surgery were also comparable between the groups. Time to eye opening was 12.2±4.973 in group B and 12.93±4.19 in group P, with a P value of 0.2664 (U-statistic-684.50). Conclusion: The intraoperative PSI and BIS had similar clinical efficacy in terms of the dose of propofol required for induction, time of induction, maintenance dose of propofol and fentanyl, time of eye opening, and recovery profile in patients undergoing elective spine surgery under neuromonitoring.

Intraoperative Transient Central Diabetes Insipidus Status Post-Cerebellopontine Meningioma Resection: A Case Report.

Central diabetes insipidus (CDI) is a neurological pathological condition in which vasopressin synthesis has been compromised. A 52-year-old male presented with a cerebellopontine angle mass not involving the hypothalamic-pituitary axis. Despite vasopressin therapy, the patient produced a total of 8650 mL of urine, with the urine-specific gravity measured at 1.002 near hour 8. A literature review found associations with certain anesthetic drugs that have an increased incidence of CDI, including alpha-2 agonists and sevoflurane. Reports have recommended administering desmopressin over vasopressin, especially for neurosurgery cases that warrant a more extended operative period, given that desmopressin has a longer context-sensitive half-life.

Decrease of the peak heights of EEG bicoherence indicated insufficiency of analgesia during surgery under general anesthesia.

BACKGROUND: Studies show that the two peak heights of electroencephalographic bicoherence (pBIC-high, pBIC-low) decrease after incision and are restored by fentanyl administration. We investigated whether pBICs are good indicators for adequacy of analgesia during surgery. METHODS: After local ethical committee approval, we enrolled 50 patients (27-65 years, ASA-PS I or II) who were scheduled elective surgery. Besides standard anesthesia monitors, to assess pBICs, we used a BIS monitor and freeware Bispectrum Analyzer for A2000. Fentanyl 5 µg/kg was completely administered before incision, and anesthesia was maintained with sevoflurane. After skin incision, when the peak of pBIC-high or pBIC-low decreased by 10% in absolute value (named LT10-high and LT10-low groups in order) or when either peak decreased to below 20% (BL20-high and BL20-low groups), an additional 1 g/kg of fentanyl was administered to examine its effect on the peak that showed a decrease. RESULTS: The mean values and standard deviation for pBIC-high 5 min before fentanyl administration, at the time of fentanyl administration, and 5 min after fentanyl administration for LT10-high group were 39.8% (10.9%), 26.9% (10.5%), and 35.7% (12.5%). And those for pBIC-low for LT10-low group were 39.5% (6.0%), 26.8% (6.4%) and 35.0% (7.0%). Those for pBIC-high for BL20-high group were 26.3% (5.6%), 16.5% (2.6%), and 25.7% (7.0%). And those for pBIC-low for BL20-low group were 26.7% (4.8%), 17.4% (1.8%) and 26.9% (5.7%), respectively. Meanwhile, at these trigger points, hemodynamic parameters didn't show significant changes. CONCLUSION: Superior to standard anesthesia monitoring, pBICs are better indicators of analgesia during surgery. TRIAL REGISTRY: Clinical trial Number and registry URL: UMIN ID: UMIN000042843 https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno = R000048907.

[Intraoperative hypotension in children-Measurement and treatment]. / Intraoperative Hypotonie beim Kind ­ Messung und Therapie.

Intraoperative hypotension is a common perioperative complication in pediatric anesthesia. Oscillometric blood pressure measurement is therefore an essential part of standard perioperative monitoring in pediatric anesthesia. The optimum measurement site is the upper arm. Attention must be paid to the correct cuff size. Blood pressure should be measured before induction. In children undergoing major surgery or in critically ill children, invasive blood pressure measurement is still the gold standard. Continuous noninvasive measurement methods could be an alternative in the future.Threshold values to define hypotension remain unknown, even in awake children. There are also little data on hypotension thresholds in the perioperative setting. The most reliable measurement parameter for estimating hypotension is the mean arterial pressure. The threshold values for intraoperative hypotension are 40 mm Hg in newborns, 45 mm Hg in infants, 50 mm Hg in young children and 65 mm Hg in adolescents. Treatment should be initiated at a deviation of 10% and intensified at a deviation of 20%.Bolus administration of isotonic balanced crystalloid solutions, vasopressors and/or catecholamines are used as treatment options. Consistent and rapid intervention in the event of hypotension appears to be crucial. So far there is no evidence as to whether this leads to an improvement in outcome parameters.

Intraoperative QTc interval interpretation: Effects of anaesthesia, ECG, correction formulae, sex, and current limits: A Prospective Observational Study.

BACKGROUND: Severe QT interval prolongation requires monitoring QTc intervals during anaesthesia with recommended therapeutic interventions at a threshold of 500 ms. The need for 12-lead ECG and lack of standardisation limit such monitoring. We determined whether automated continuous intraoperative QTc monitoring with 5-lead ECG measures QTc intervals comparable to 12-lead ECG and whether the interpretation of QTc intervals depends on the correction formulae and the patient's sex. We compared intraoperative QTc times to QTc times from resting ECGs of a population from the same region, to substantiate the hypothesis that patients under general anaesthesia may need specific treatment thresholds. METHODS: In this prospective observational study, intraoperative QT/QTc intervals were automatically recorded using 12 and 5-lead ECG in 100 patients (44% males). QTc values were analysed for sex and formula-specific aspects after correction for heart rate according to Bazett, Fridericia, Hodges, Framingham, Charbit and QTcRAS, and compared to a regional community-based cohort. The level of significance was set to α = 0.05. RESULTS: QT interval duration was not significantly different between 12-lead and 5-lead ECG (difference - 0.09 ms ± 8.5 ms, p = 0.793). The QTc interval duration significantly differed between the correction formulae (p < 0.001) and between sexes (p < 0.001). Mean intraoperative QTc duration was higher than in resting ECGs from a large community-based population with the same regional background (438 vs. 417 ms). The incidence of prolonged values >500 ms significantly depended on the correction formula (p < 0.001) and was up to tenfold higher in women versus men. CONCLUSION: Intraoperative QTc interval measurement using a 5-lead ECG is valid. Correction formulae and gender influence the intraoperative QTc interval duration and the incidence of pathologically prolonged values according to current limits. The consideration and definition of sex-specific normal limits for QTc times under general anaesthesia, therefore, warrant further investigation.

Cortical and subcortical intraoperative-monitoring of the visual pathway under general anesthesia in epilepsy surgery.

OBJECTIVE: The purpose of this study was to evaluate the applicability of visual evoked potentials (VEP) for intraoperative visual pathway monitoring in epilepsy surgery of the posterior hemispheric quadrant (PHQ) and to correlate it with post-operative visual field status. METHODS: VEP monitoring was performed in 16 patients (12 females, 7 children). Flash-induced VEP were recorded with strip electrodes from the banks of the calcarine cortex. Latency and amplitude of the first component of VEP (V1-lat, V1-amp) were monitored. Evaluation of the visual field was performed pre- and post-operatively in all patients. RESULTS: All procedures were successfully completed without adverse events. In 10 patients the strip covered both the inferior and superior calcarine banks, while only one bank was sampled in 6 cases (inferior in 4, superior in 2). Considering one of the two calcarine banks, at the end of the resection VEP had disappeared in 4 patients, whereas a decrease >33.3% in 4 and <20% of V1-amp was recorded in 5 and in 4 cases respectively. The percentage of V1-amp reduction was significantly higher for the patients who experienced a post-operative visual field reduction (p < 0.001). Post-operative visual field deficits were found in patients presenting a reduction >33.3% of V1-amp. CONCLUSIONS: VEP monitoring is possible and safe in epilepsy surgery under general anesthesia. SIGNIFICANCE: Intraoperative recording of VEP from the banks of the calcarine cortex allows monitoring the integrity of post-geniculate visual pathways during PHQ resections for epilepsy and it is pivotal to prevent disabling visual field defects, including hemianopia and inferior quadrantanopia.

Use of the cardiac power index to predict fluid responsiveness in the prone position: a proof-of-concept study.

BACKGROUND: The primary aim of this proof-of-concept study was to investigate whether the Cardiac Power Index (CPI) could be a novel alternative method to assess fluid responsiveness in the prone position. METHODS: Patients undergoing scheduled elective lumbar spine surgery in the prone position under general anesthesia were enrolled in the criteria of patients aged 19-75 years with American Society of Anesthesiologists (ASA) physical status I-II. The hemodynamic variables were evaluated before and after changes in posture after administering a colloid bolus (5 mL.kg-1) in the prone position. Fluid responsiveness was defined as an increase in the Stroke Volume Index (SVI) ≥ 10%. RESULTS: A total of 28 patients were enrolled. In responders, the CPI (median [1/4Q-3/4Q]) decreased to 0.34 [0.28-0.39] W.m-2 (p = 0.035) after the prone position. After following fluid loading, CPI increased to 0.48 [0.37-0.52] W.m-2 (p < 0.008), and decreased SVI (median [1/4Q-3/4Q]) after prone increased from 26.0 [24.5-28.0] mL.m-2 to 33.0 [31.0-37.5] mL.m-2 (p = 0.014). Among non-responders, CPI decreased to 0.43 [0.28-0.53] W.m-2 (p = 0.011), and SVI decreased to 29.0 [23.5-34.8] mL.m-2 (p < 0.009). CPI exhibited predictive capabilities for fluid responsiveness as a receiver operating characteristic curve of 0.78 [95% Confidence Interval, 0.60-0.95; p = 0.025]. CONCLUSION: This study suggests the potential of CPI as an alternative method to existing preload indices in assessing fluid responsiveness in clinical scenarios, offering potential benefits for responders and non-responders.

Impact of Latency Variations on the Predictive Value of Facial Nerve Proximal-to-Distal Amplitude Ratio during Vestibular Schwannoma Surgery.

Introduction This study highlights the relation between compound muscle action potential (CMAP) latency variations and the predictive value of facial nerve (FN) proximal-to-distal (P/D) amplitude ratio measured at the end of vestibular schwannoma resection. Methods Forty-eight patients underwent FN stimulation at the brainstem (proximal) and internal acoustic meatus (distal) using a current intensity of 2 mA. The proximal latency and the P/D amplitude ratio were assessed. House-Brackmann grades I & II indicated good FN function, and grades III to VI were considered fair/poor function. A P/D amplitude ratio > 0.6 was used as a cutoff to indicate a good FN function, while a ratio of ≤ 0.6 indicated a fair/poor FN function. Results The P/D amplitude ratio was measured for all patients, and the calculated sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) were 85.2, 85.7, 88.5, and 81.8%, respectively. The CMAPs from the mentalis muscle were then classified based on their proximal latency into group I (< 6 ms), group II (6-8 ms), and group III (> 8 ms). The SE, SP, PPV, and NPV became 90.5, 90.9, 95, and 83.3%, respectively, in group II. In group I, SE and NPV increased, whereas SP and PPV decreased. While in group III, SP and PPV increased, whereas SE and NPV decreased. Conclusion At a latency between 6 and 8 ms, the P/D amplitude ratio was predictive of outcomes with high SE and SP. When latency was < 6 ms or > 8 ms, the same predictive ability was not observed. Knowing the strengths and limitations is important for understanding the predictive value of the P/D amplitude ratio.

Intraoperative Hearing Monitoring Using ABR and TT-ECochG and Hearing Preservation during Vestibular Schwannoma Resection.

Background: Quick and appropriate diagnostics and the use of intraoperative monitoring (IM) of hearing during vestibular schwannoma (VS) resection increase the likelihood of hearing preservation. During surgery, various methods of IM can be used, i.e., auditory brainstem responses (ABRs), transtympanic electrocochleography (TT-ECochG), and direct cochlear nerve action potentials. The aim of the study was to evaluate the prognostic values of IM of hearing using ABR and TT-ECochG in predicting postoperative hearing preservation and to evaluate relationships between them during various stages of surgery. Methods: This retrospective study presents the pre- and postoperative audiological test results and IM of hearing records (TT-ECochG and ABR) in 75 (43 women, 32 men, aged 18-69) patients with diagnosed VS. Results: The preoperative pure tone average hearing threshold was 25.02 dB HL, while after VS resection, it worsened on average by 30.03 dB HL. According to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) Hearing Classification, before and after (pre/post) surgery, there were 47/24 patients in hearing class A, 9/8 in B, 2/1 in C, and 17/42 in D. In speech audiometry, the average preoperative speech discrimination score at an intensity of 60 dB SPL was 70.93%, and after VS resection, it worsened to 38.93%. The analysis of electrophysiological tests showed that before the tumor removal the I-V ABR interlatencies was 5.06 ms, and after VS resection, it was 6.43 ms. Conclusions: The study revealed correlations between worse postoperative hearing and changes in intraoperatively measured ABR and TT-ECochG. IM of hearing is very useful in predicting postoperative hearing in VS patients and increases the chance of postoperative hearing preservation in these patients.

Cortico-cortical evoked potential and language mapping: A meta-analysis.

PURPOSE: The purpose of this meta-analysis was to determine the best available evidence for the use of cortico-cortical evoked potential (CCEP) for language mapping. METHODS: PubMed/Medline/Google Scholar/Cochrane and Scopus electronic databases were searched for articles using CCEP for language mapping. CCEP data was obtained including the area of the cortex generating CCEP, resection data, and post-resection language outcomes. Inclusion criteria were clinical articles reporting the use of CCEP in language regions of the brain, reporting language outcomes and whether there was final resection of the cortex, studies with more than five patients, and studies in either English or Spanish. Review articles, systematic reviews, meta-analyses, or case series with less than five patients were excluded. RESULTS: Seven studies with a total of 59 patients were included in this meta-analysis. The presence of CCEPs from stimulation of Broca's area or posterior perisylvian region in the resection predicts language deficits after surgery. The diagnostic odds ratio shows values greater than 0 perioperatively (0.69-5.82) and after six months (1.38-11), supporting a high likelihood of a language deficit if the presence of CCEPs from stimulation of Broca's area or posterior perisylvian region are included in the resection and vice versa. The True Positive rate varied between 0.38 and 0.87. This effect decreases after six months to 0.61 (0.30-0.86). However, the True Negative rate increased from 0.53 (0.32-0.79) to 0.71 (0.55-0.88). CONCLUSION: This meta-analysis supports the utility of CCEP to predict the probability of having long-term language deficits after surgery. .

Dynamic parameters of fluid responsiveness in the operating room : An analysis of intraoperative ventilation framework conditions.

BACKGROUND: Reliable assessment of fluid responsiveness with pulse pressure variation (PPV) depends on certain ventilation-related preconditions; however, some of these requirements are in contrast with recommendations for protective ventilation. OBJECTIVE: The aim of this study was to evaluate the applicability of PPV in patients undergoing non-cardiac surgery by retrospectively analyzing intraoperative ventilation data. MATERIAL AND METHODS: Intraoperative ventilation data from three large medical centers in Germany and Switzerland from January to December 2018 were extracted from electronic patient records and pseudonymized; 10,334 complete data sets were analyzed with respect to the ventilation parameters set as well as demographic and medical data. RESULTS: In 6.3% of the 3398 included anesthesia records, patients were ventilated with mean tidal volumes (mTV) > 8 ml/kg predicted body weight (PBW). These would qualify for PPV-based hemodynamic assessment, but the majority were ventilated with lower mTVs. In patients who underwent abdominal surgery (75.5% of analyzed cases), mTVs > 8 ml/kg PBW were used in 5.5% of cases, which did not differ between laparoscopic (44.9%) and open (55.1%) approaches. Other obstacles to the use of PPV, such as elevated positive end-expiratory pressure (PEEP) or increased respiratory rate, were also identified. Of all the cases 6.0% were ventilated with a mTV of > 8 ml/kg PBW and a PEEP of 5-10 cmH2O and 0.3% were ventilated with a mTV > 8 ml/kg PBW and a PEEP of > 10 cmH2O. CONCLUSION: The data suggest that only few patients meet the currently defined TV (of > 8 ml/kg PBW) for assessment of fluid responsiveness using PPV during surgery.

Intraoperative monitoring of trigeminal neuralgia: a technical note.

Trigeminal neuralgia causes excruciating pain in patients. Microvascular decompression is indicated for drug-resistant s trigeminal neuralgia. Unlike facial spasms, any part of the nerve can be the culprit, not only the root entry zone. Intraoperative monitoring does not yet exist for trigeminal neuralgia. We successfully used intermittent stimulation of the superior cerebellar artery during surgery and confirmed the disappearance of the trigeminal nerve motor branch reaction after the release of the compression. Intermittent direct stimulation of the culprit blood vessel using the motor branch of the trigeminal nerve may assist in intraoperative monitoring of decompression during trigeminal nerve vascular decompression surgery.

An update on tests used for intraoperative monitoring of cognition during awake craniotomy.

PURPOSE: Mapping higher-order cognitive functions during awake brain surgery is important for cognitive preservation which is related to postoperative quality of life. A systematic review from 2018 about neuropsychological tests used during awake craniotomy made clear that until 2017 language was most often monitored and that the other cognitive domains were underexposed (Ruis, J Clin Exp Neuropsychol 40(10):1081-1104, 218). The field of awake craniotomy and cognitive monitoring is however developing rapidly. The aim of the current review is therefore, to investigate whether there is a change in the field towards incorporation of new tests and more complete mapping of (higher-order) cognitive functions. METHODS: We replicated the systematic search of the study from 2018 in PubMed and Embase from February 2017 to November 2023, yielding 5130 potentially relevant articles. We used the artificial machine learning tool ASReview for screening and included 272 papers that gave a detailed description of the neuropsychological tests used during awake craniotomy. RESULTS: Comparable to the previous study of 2018, the majority of studies (90.4%) reported tests for assessing language functions (Ruis, J Clin Exp Neuropsychol 40(10):1081-1104, 218). Nevertheless, an increasing number of studies now also describe tests for monitoring visuospatial functions, social cognition, and executive functions. CONCLUSIONS: Language remains the most extensively tested cognitive domain. However, a broader range of tests are now implemented during awake craniotomy and there are (new developed) tests which received more attention. The rapid development in the field is reflected in the included studies in this review. Nevertheless, for some cognitive domains (e.g., executive functions and memory), there is still a need for developing tests that can be used during awake surgery.

Utility and Prognostic Value of Intraoperative Blink Reflex in Trigeminal or Facial Nerve Monitoring in Skull Base Surgeries: A Systematic Review.

BACKGROUND: Blink reflex (BR) is an oligosynaptic reflex that involves the ophthalmic branch of the trigeminal nerve (TN), ipsilateral main sensory and trigeminospinal nuclei, bilateral facial nuclei, and the facial nerves (FNs). Theoretically, as BR tests the function of both TN and FNs simultaneously, it is an ideal tool for monitoring the status of TN and FNs during skull base surgeries. Nevertheless, it has been used only recently in surgeries as the use of anesthesia limits its use. METHODS: For this systematic review, 2 authors input the search terms [(Blink Reflex) AND (Intraoperative Neuromonitoring OR Neuro Intraoperative Monitoring OR Intraoperative OR NIOM OR IONM) AND (skull base surgery OR Facial Nerve OR Trigeminal Nerve OR Microvascular Decompression OR Hemifacial Spasm)] in MEDLINE through its PubMed interface and other search engines. Articles that fulfilled the inclusion and exclusion criteria were obtained and scrutinized. RESULTS: Seven observational articles with a total of 437 participants were included. All 5 studies that described the use of BR in FN surgery noted that intraoperative BR is beneficial, safe, sensitive, specific, and predictive of outcomes, while 2 articles describing patients with trigeminal neuralgia recommended use of BR in microvascular decompression of TN. CONCLUSIONS: Intraoperative BR is a sensitive, specific, and safe monitoring technique that has good predictability of facial paresis and paresthesia among patients undergoing MVD for trigeminal neuralgia and primary hemifacial spasm and patients undergoing cerebellopontine angle tumor resection.

Skin conductance algesimeter is unreliable during sudden perioperative temperature increases.

OBJECTIVES: Pain assessment in anesthetized and non-communicative patients remains a challenge. Clinical signs such as tachycardia, hypertension, sweat and tears, have a low specificity for pain and should therefore ideally be replaced by more specific monitoring techniques. Skin conductance variability has been demonstrated to establish a patients' sensitivity to pain, but may be influenced by temperature changes that leads to profuse sweating. The aim of this pilot study was to test skin conductance changes during sudden temperature changes due to hyperthermic intraperitoneal chemotherapy (HIPEC) perfusation. METHODS: We investigated skin conductance algesimeter (SCA) in ten consecutive patients undergoing cytoreductive surgery and HIPEC. Results from the SCA was compared to other standard physiological variables at seven time points during the surgical procedure, in particular during the period with hyperthermic intraabdominal perfusion leading to an increase in the patients core temperature. RESULTS: Nine out of ten patients had an increase in the SCA measurements during the HIPEC phase correlating the increase in temperature. CONCLUSION: SCA is unreliable to detect increased pain sensation during sudden perioperative temperature changes in adult patients.