BACKGROUND:Chronic postoperative pain after breast cancer surgery varies substantially among patients and may reflect individual neurophysiological susceptibility. We explored whether preoperative resting-state electroencephalography (EEG) features are associated with clinically significant chronic postoperative pain. METHODS:In this prospective cohort study, 100 female patients scheduled for mastectomy or breast-conserving surgery were enrolled. After exclusions for incomplete EEG acquisition, protocol changes, loss to follow-up, or poor EEG quality, 84 patients were analyzed. Preoperative variables included age, body mass index, American Society of Anesthesiologists physical status, neoadjuvant chemotherapy, surgical approach, and axillary lymph node dissection (ALND). At 3 months, patients were classified as higher-pain (HP; Numeric Rating Scale [NRS] ≥4) or lower-pain (LP; NRS <4). Exploratory analyses compared clinical characteristics, spectral power, and functional connectivity between groups. RESULTS:Twenty-seven patients (32.1%) were classified as HP. The median [IQR] 3-month NRS score was 5 [4 to 6] in the HP group and 1 [0 to 2] in the LP group. Mastectomy versus breast-conserving surgery (OR=3.43, 95% CI: 1.31-8.99; P=0.010) and ALND versus no ALND (OR=5.75, 95% CI: 2.12-15.59; P<0.001) were associated with higher pain. Preoperative gamma-band power at F3, Fz, and F4 was higher in HP patients, with no group differences in other bands. Gamma-band connectivity involving frontal, insular, and cingulate regions was also stronger in the HP group. CONCLUSIONS:Preoperative frontal gamma activity and connectivity may reflect baseline neurophysiological vulnerability to chronic postoperative pain after breast cancer surgery. These exploratory group-level findings warrant validation in larger cohorts.
BACKGROUND:F-waves are produced by the re-excitation of spinal anterior horn cells following distal electrical stimulation without being mediated through a conventional monosynaptic reflex pathway. F-waves can often be recorded even when voluntary motor output is limited and have been investigated as an adjunctive modality for intraoperative neurophysiological monitoring. However, some anesthetic agents affect intraoperative spinal neuromonitoring. Remimazolam is a novel, relatively safe anesthetic agent, especially for older adults, and its effects on F-waves are unclear. Therefore, we aimed to assess F-waves in patients undergoing spine and spinal cord surgery under remimazolam anesthesia. METHODS:We prospectively evaluated 25 patients scheduled for prolonged spine or spinal cord surgery (≥3 h). F-waves were intraoperatively recorded from the left abductor hallucis at baseline and hourly thereafter. The persistence, normalized minimum latency, and amplitudes of the F-waves and F/M amplitude ratio were determined. In addition, their longitudinal changes under remimazolam anesthesia were assessed using linear mixed-effects models. Multivariable linear regression analysis was performed to identify factors associated with a change in F-wave persistence at 3 hours. Age, preoperative manual muscle test score, and baseline persistence were included as covariates. RESULTS:None of the F-wave parameters showed significant time-dependent changes. The preoperative manual muscle test result was not an independent predictor of the change in F-wave persistence observed in the multivariable model. CONCLUSIONS:F-waves remained recordable without significant time-dependent changes in most patients under remimazolam anesthesia for up to 3 hours, suggesting that remimazolam has minimal effects on F-wave recordings.
INTRODUCTION:Pain control remains a challenge after neurosurgery. Opioid-sparing analgesia may provide better pain relief without opioid-related side effects after craniotomy. We aimed to compare analgesia requirement and postoperative pain between opioid-sparing and opioid-based analgesia for craniotomy. METHODS:This investigator-initiated, multicenter randomized controlled trial was conducted at 5 Indian centers from October 19, 2022, to September 5, 2024, in adult patients undergoing elective craniotomy for brain tumors, following trial registration (CTRI/2022/09/045705, September 20, 2022). Patients received fentanyl 1 µg.kg-1.h-1 or dexmedetomidine 0.5 µg.kg-1.h-1 in a 1:1 allocation ratio after anesthetic induction until dural closure as the primary systemic analgesic. In addition, patients received intraoperative loco-regional analgesia. Our primary outcomes were intraoperative rescue opioid consumption and incidence of moderate-to-severe pain on the numerical rating scale (NRS) in the postanesthesia care unit (PACU). Secondary outcomes were pain on the first 2 postoperative days, drug-associated harms, recovery profile, patient satisfaction, quality of sleep, hospital stay duration, and persistent pain at 3 and 6 months. RESULTS:There was no difference between fentanyl (n=252) and dexmedetomidine (n=248) groups for rescue fentanyl (38.0±63.1 vs. 44.6±81.7 μg, P=0.327) or moderate-to-severe pain in the PACU (145/242 vs. 138/233, P=0.559). Intraoperative hypotension was more common with dexmedetomidine (100/248 vs. 75/252, P=0.015), while shivering was lower than with fentanyl (9/241 vs. 22/251, P=0.026). Other outcomes were similar between groups. CONCLUSIONS:Both opioid-based and opioid-sparing regimens were similar regarding rescue analgesia, postoperative pain, and other in-hospital outcomes in patients undergoing craniotomy. Dexmedetomidine increased the occurrence of intraoperative hypotension and reduced postoperative shivering compared with fentanyl.
Background: Pulse pressure variation (PPV) is widely used to guide fluid responsiveness in mechanically ventilated patients, but its accuracy in the prone position remains uncertain. Prone positioning alters respiratory mechanics and venous return, potentially diminishing the respiratory variation in stroke volume that PPV is designed to detect. We conducted a systematic review and meta-analysis to evaluate the diagnostic accuracy of PPV for predicting fluid responsiveness during prone spine surgery. Methods: We searched MEDLINE, Embase, Scopus, and Cochrane through July 2025 for prospective studies evaluating PPV in adults undergoing prone spine surgery. Two reviewers independently screened studies, extracted data, assessed risk of bias using QUADAS-2, and pooled diagnostic performance using a bivariate random-effects model. The protocol was registered with PROSPERO (CRD420251106134). Results: Of 599 records, 34 underwent full-text review, and 10 studies (433 patients) were included. PPV thresholds ranged from 7% to 15%. Most studies were at low risk of bias except for the index test because thresholds were determined post hoc. For predicting fluid responsiveness, PPV had a pooled sensitivity of 68% (95% CI: 61%-75%) and specificity of 76% (95% CI: 65%-84%), with a summary area under the receiver operating characteristic curve of 0.72 (95% CI: 0.64-0.80). Conclusions: PPV showed only moderate diagnostic performance for predicting fluid responsiveness during prone spine surgery. Its performance may have been influenced by threshold variability, heterogeneous reference standards, fluid-challenge protocols, ventilation strategies, and positioning systems. PPV should therefore be interpreted alongside complementary dynamic assessments rather than in isolation, particularly during lung-protective ventilation.
Background: Occipitocervical fusions (OCFs) are associated with adverse airway events. The period of airway compromise remains poorly defined. The objective of this study was to identify differences between OCF and posterior cervical fusion not involving the occipitocervical joint (NOCF) in the timing and incidence of postoperative airway interventions. Methods: Using the 2017 to 2022 Nationwide Inpatient Sample, we identified 1908 OCF and 38,743 NOCF hospitalizations (excluding anterior surgeries and spinal cord injury at or above C5). Survey‑weighted logistic regression and competing‑risks analysis were used to assess the incidence and temporal patterns of postoperative airway instrumentation. Results: OCF was associated with higher odds of tracheostomy (6.34% vs. 1.35%; adjusted OR=2.42; 95% CI: 1.92-3.05; P <0.001) and reintubation (2.10% vs. 0.78%; OR=1.54; 95% CI: 1.09-2.19; P =0.015) overall. On qualitative assessment of cumulative incidence curves, OCF demonstrated a distinct temporal crossover: tracheostomies exceeded reintubations by POD 3. Reintubation leveled off near the second postoperative week after OCF compared with the first week after NOCF, while tracheostomy placement leveled off around the third week after OCF compared with the second week after NOCF. The weighted 30-day cumulative incidence of tracheostomy was 5.31% for OCF versus 1.22% for NOCF (Gray P <0.001), and for reintubation it was 2.10% versus 0.77% (Gray P <0.001), with death and discharge as competing events. Conclusion: Following OCF, postoperative tracheostomies and reintubations occur more frequently and over a more prolonged postoperative period compared with NOCF. By POD 3, tracheostomies were performed more frequently than reintubations in OCF.
INTRODUCTION:Midazolam has been shown to induce transient motor deficits in patients with supratentorial gliomas. However, its effects on brain networks remain unclear, given the compensatory network reorganization in response to tumor-induced damage. This study examined sensorimotor network (SMN) intra- and internetwork functional connectivity before and after midazolam mild sedation in patients with motor cortex gliomas, compared with healthy controls. METHODS:Glioma patients and healthy volunteers underwent resting-state functional MRI in the awake state and mild midazolam sedation. Regions of interest were defined in the primary motor cortex (M1) using a 6 mm radius. Statistical significance was set at an uncorrected voxel-wise threshold of P<0.001 and a false discovery rate-corrected cluster-wise threshold of P<0.05. This trial was registered at clinicaltrials.gov (NCT03984240) on June 11, 2019. RESULTS:Thirty-four participants (18 glioma patients and 16 healthy volunteers) were analyzed. Glioma patients showed reduced negative functional connectivity between the SMN and the default mode network (DMN) in the awake state (P<0.05) and decreased SMN intranetwork connectivity. Following mild midazolam sedation, glioma patients demonstrated enhanced SMN intranetwork connectivity, with increased connectivity between M1 and the bilateral precentral gyrus, postcentral gyrus, and supramarginal regions (all P<0.001). Internetwork connectivity was decreased between M1 and the temporal fusiform cortex (T=8.05 and P=0.01), and between M1 and the occipital fusiform gyrus/inferior lateral occipital cortex (T=5.88 and P=0.002). CONCLUSION:Midazolam mild sedation alters SMN connectivity in glioma patients, characterized by enhanced intranetwork compensation and impaired cross-network integration. These findings suggest potential vulnerabilities of functional brain networks during the perioperative period.
The optimal anesthetic technique during endovascular thrombectomy (EVT) for acute ischemic stroke (AIS) remains uncertain. General anesthesia (GA) provides airway protection and procedural stability, whereas conscious sedation (CS) offers faster workflow and the ability to monitor neurological status. This updated systematic review and meta-analysis (SRMA) aims to summarize and update the existing literature from randomized controlled trials (RCTs) to guide the selection of the most appropriate anesthetic technique during EVT for AIS. We searched the electronic databases of PubMed, ProQuest, and Scopus from their inception to October 17, 2025. No time or language restrictions were applied. Only RCTs were included. The SRMA protocol was registered with PROSPERO (ID: CRD420251170612) on 18th October 2025. Statistical analysis was performed using Review Manager software. Risk of bias (RoB) and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) were assessed. Of the 348 records screened, ten eligible RCTs were included. GA was associated with a significantly higher rate of successful reperfusion, but there was no difference in 90-day functional independence on modified Rankin scale (mRS) score, or mortality compared with CS. GA increased the risk of hypotension and prolonged the door-to-puncture time, but not other complications or process times. The RoB was low for most included studies. The certainty of evidence for study outcomes was moderate on GRADE. To conclude, GA has superior recanalization rates than CS, but functional outcomes and mortality are similar. Conversely, hypotension occurs more frequently with GA, while CS provides a faster workflow.
Preoperative anxiety is common in patients undergoing neurosurgical procedures and is known to influence the perioperative experience, pharmacologic decisions, and postoperative outcomes. In awake neurosurgery procedures, anxiety is of particular relevance because the success of the procedure depends on sustained patient cooperation and intact cognitive performance under stress. Anxiety comprises transient situational responses to threat (state anxiety) as well as more stable individual predispositions (trait anxiety). In this narrative review, we first describe the concepts of state and trait anxiety in the preoperative context of awake brain surgery. We then review commonly used measurement instruments and discuss their respective strengths and limitations in capturing preoperative anxiety as a state versus a trait. Including descriptions of brief screening tools, state-trait inventories (e.g., State-Trait Anxiety Inventory STAI), and medical procedure-specific instruments such as the Amsterdam Preoperative Anxiety and Information Scale (APAIS). We further propose expert-based practical considerations for incorporating anxiety phenotyping into preoperative planning to support individualized anesthetic strategies and informed awake-versus-asleep decision-making in neurosurgery. Also, we integrate findings from perioperative neuroscience and neurocognitive research to explore potential mechanisms by which trait anxiety may impair cognitive flexibility and increase vulnerability of frontal executive networks under perioperative stress. These mechanisms have direct clinical relevance, as they may influence patient selection for awake techniques, anesthetic strategies, intraoperative task performance, and susceptibility to postoperative cognitive disturbances.
Airway complications after cervical spine surgery are infrequent but potentially catastrophic. The mechanisms of postoperative airway compromise differ according to surgical approach, extent of surgery, and underlying cervical pathology and include prevertebral and airway soft-tissue edema, retropharyngeal hematoma, recurrent laryngeal nerve dysfunction, cervical malalignment, and restricted cervical mobility. In patients with concomitant cervical spinal cord injury or myelopathy, impaired respiratory mechanics and bulbar dysfunction may further increase airway vulnerability. Recent evidence suggests that postoperative airway vulnerability is dynamic rather than confined to the immediate perioperative period, with clinically significant respiratory and swallowing complications occurring days to weeks after surgery, including some after hospital discharge. This focused review summarizes contemporary evidence regarding perioperative risk stratification, pathophysiology, extubation planning, postoperative surveillance, and preventive strategies for airway complications after cervical spine surgery. Potentially modifiable perioperative interventions, including goal-directed fluid therapy, corticosteroid administration, endotracheal tube cuff-pressure management, and selective delayed extubation in selected high-risk patients, are discussed. Although current evidence supports protocolized multidisciplinary airway management pathways, important gaps remain regarding individualized prediction of postoperative airway compromise, optimal extubation criteria, and postoperative monitoring strategy.
Major spine surgery is associated with substantial blood loss and dynamic perioperative coagulation disturbances. Conventional coagulation tests may not adequately assess whole-blood clot formation, platelet contribution, or fibrinolysis. Viscoelastic hemostatic assays (VHAs), including thromboelastography and rotational thromboelastometry, have been explored for point-of-care coagulation assessment in spine surgery. This scoping review systematically mapped the literature evaluating VHA-guided transfusion practices and perioperative coagulation assessment in spine surgery, focusing on devices used, timing of testing, and reported clinical outcomes. The primary objective was evidence mapping rather than quantitative effect estimation or meta-analysis. The review followed a Population-Concept-Context framework and was reported in accordance with PRISMA-ScR guidelines. Electronic databases and gray literature were searched from inception to August 29, 2025. Eligible studies included patients undergoing spine surgery in whom VHAs were used perioperatively, evaluating system-level outcomes (devices, timing, algorithms, cost-effectiveness) and clinical outcomes (blood loss, transfusion composition and volume, pharmacotherapy, hypercoagulability, and hospital length of stay). Twenty-one studies met inclusion criteria, comprising 3 randomized controlled trials, 9 prospective observational studies, 8 retrospective cohort studies, and 1 case-control study. Most studies were observational with marked heterogeneity in design, patient populations, and surgical settings. Several studies reported targeted blood product administration with VHA-guided management. Evidence regarding reductions in blood loss and hospital stay was inconsistent, while data on hypercoagulability, thromboembolic events, and cost-effectiveness were limited. Though studies suggest that VHA may guide patient blood management in spine surgery, the evidence is predominantly observational, limiting causal inference and underscoring the need for well-designed, spine-specific studies.
BACKGROUND:The metabolic component of cerebral autoregulation is crucial in traumatic brain injury (TBI), yet continuously monitored indices are limited. This study introduces the ICP-EtCO2 Slope (IESlope), quantifying the dynamic relationship between end-tidal CO2 (EtCO2) and intracranial pressure (ICP), and evaluates its association with 12-month mortality and unfavorable outcome (Glasgow Outcome Scale-Extended, GOSE≤4). Second, IESlope visualization and its ability to predict short-term ICP changes during EtCO2 variations are assessed. METHODS:Intensive care unit records of 218 adult and pediatric TBI patients were retrospectively analyzed (median age 44, IQR: 24-66; 76% male). IESlope was calculated as the angle of the linear regression between EtCO2 and ICP over 60-minute moving windows and visualized using streamline mapping (ICP-EtCO2 space). IESlope values were averaged to obtain a single patient-level metric used in univariate and multivariable analyses (area under the curve, AUC). Predictive capability was assessed by comparing predicted versus observed ICP changes at 5, 10, and 20 minutes during significant EtCO2 variations. RESULTS:Lower IESlope values were associated with mortality and GOSE≤4 (median: 7.76 vs. 14.8 and 10.5 vs. 18.6, respectively, P<0.001), independent of age or decompressive craniectomy. Streamline maps showed expected CO2 reactivity patterns, with peak values at moderate ICP and EtCO2 levels and reductions at extremes and after decompressive craniectomy. IESlope maintained significant associations with outcomes (AUC ∼0.900) and accurately predicted short-term ICP responses to EtCO2 changes (mean absolute error, MAE=0.600-1.686 mm Hg). CONCLUSIONS:IESlope provides a continuous, quantitative measure of CO2-related ICP reactivity and may support individualized ventilatory management in TBI, pending prospective validation.
Opioid-free anesthesia (OFA) offers potential benefits of smoother recovery and reduced complications, compared with conventional opioid-based approach. We aimed to evaluate the use of OFA as an alternative approach to conventional opioid-based anesthetic regimen in patients undergoing supratentorial brain tumor surgery. Adult patients (>18 y) with supratentorial tumors undergoing elective craniotomy under general anesthesia (Aug 2022 to Dec 2023) were randomized into Dexmedetomidine (group D) or Fentanyl (group F) group. Primary outcome included emergence and extubation times and secondary outcomes were hemodynamic responses, pain scores, rescue analgesic use, and complications. A total of 44 patients were randomized (22 per group). Of these, 33 patients completed the study. Demographic variables were comparable, except for age and body mass index. Emergence (8.2±3.3 min vs. 6.8±2.6 min [ P =0.18]; Mean Difference [MD], 95% CI: 1.42, −0.69 to 3.55) and extubation times (12.7±4.2 min vs. 11.2±3.9 min [ P =0.27]; MD, 95% CI: 1.58, −1.31 to 4.46) were comparable between the groups, respectively. Group D demonstrated better hemodynamic stability during Mayfield pin application and tracheal extubation. Postoperative pain scores were similar, except at 12 hours, where group D reported lower Numerical Rating Scale. Postoperative Richmond Agitation-Sedation Scale at different time points was comparable between the groups. Our preliminary data suggest that OFA may provide better hemodynamic stability and improved pain control at 12 hours compared with opioid-based anesthesia, while maintaining similar emergence and extubation times.
