Objective:Corrective spinal surgery involving pedicle subtraction osteotomy is a demanding procedure associated with a high risk of complications, particularly in elderly patients. Staged approaches have been proposed to reduce perioperative risk and patients' burden; nevertheless, evidence in this population is limited. Research question:This study compares single versus two-staged approaches in elderly patients, assessing short-term outcomes and complication severity. Methods:Fifty-one patients who underwent corrective spinal fusion with pedicle subtraction osteotomy between 2014 and 2023 were retrospectively analyzed. Clinical characteristics and complications were compared, with complications classified using the modified Clavien-Dindo-Sink classification. Results:The median age was 70 and 71 years in the single-stage group (1-SG, n = 30) vs. the two-stage group (2-SG, n = 21). Baseline characteristics and the number of instrumented segments (1-SG: 9.7 ± 4.2; 2-SG: 10.6 ± 3.4) were comparable. Cumulative operative time was significantly shorter in 1-SG (431 ± 131 min) compared with 2-SG (653 ± 142 min). However, perioperative parameters, including estimated blood loss, transfusion rate, hospital stay, and discharge modality, showed no significant differences. The incidence and severity of complications within 90 days were also comparable across both groups. Conclusions:This study demonstrates no beneficial effect of staged surgery for corrective spine surgery in elderly patients. The findings suggest that overall surgical invasiveness, rather than timing strategy, is more critical when prolonged operating times and high blood loss are expected.

Chronic subdural hematoma (cSDH) is a common condition in older adults that often requires neurosurgical evacuation. Postoperative delirium is a frequent and clinically relevant postoperative complication in this population. This study investigated whether burr hole craniotomy for cSDH performed under local anesthesia (LA) reduces the risk of postoperative delirium and complications compared to general anesthesia (GA). The ABC-SDH trial was a single-center, open-label, phase 2, prospective randomized clinical trial conducted at a tertiary academic medical center between October 2023 and November 2024. Fifty consecutive patients with a confirmed diagnosis of cSDH underwent burr hole craniotomy performed under either LA or GA. Primary outcomes were postoperative delirium (Confusion Assessment Method, CAM) and complications rates until discharge, and the recruitment rate. Secondary outcomes included procedural times and clinical outcome measures at discharge and at 30-day follow-up. LA was associated with a significantly lower rate of postoperative delirium (4

OBJECTIVE:The middle meningeal artery (MMA) often traverses a bony canal, rendering it vulnerable during craniotomy. In moyamoya disease (MMD), it serves as a collateral pathway for cerebral perfusion, making vessel preservation essential during bypass surgery. This study examined the anatomy of MMA bony canals in dry skulls and compared findings in patients with MMD and atherosclerotic cerebrovascular disease (ACVD). METHODS:A total of 175 adult and pediatric dry skulls and cranial CT scans of MMD (n = 100) and ACVD (n = 100) patients were analyzed retrospectively. The relationship of bony canals to the convergence of the coronal, sphenofrontal, and sphenoparietal sutures, serving as an anatomical landmark, was assessed. RESULTS:Bony canals containing the frontal MMA branch were present in 91.2% of adult skulls (≥ 18 years). Before fontanelle closure (< 2 years), the incidence was 1.8%, increasing to 47.7% in skulls ≥ 2 years (p < 0.0001). The mean canal length was 12.0 ± 5.9 mm in adult skulls, 10.1 ± 4.5 mm in skulls ≥ 2 years, and 7.5 ± 3.5 mm in skulls < 2 years (p = 0.212). In adult skulls, the mean distances of the canal entry and exit points posterior to the landmark were 11.6 ± 4.8 mm and 13.8 ± 6.4 mm, respectively. Parietal branch canals were rare (≤ 12.9%) and typically located below the squamous suture. Clinically, MMD patients were younger than ACVD patients (41.6 ± 12.2 vs 55.0 ± 11.6 years, p < 0.0001) and had a similar prevalence of frontal branch canals (80.0% vs 84.0%, p = 0.36). Bony canals were longer (15.9 ± 9.7 mm vs 13.3 ± 6.2 mm, p = 0.02) and wider (1.6 ± 0.4 mm vs 1.3 ± 0.5 mm, p < 0.0001) in MMD patients. CONCLUSIONS:After fontanelle closure, the likelihood of the MMA traversing a bony canal located within one thumb's width posterior to the pterion increases with age. Comprehensive knowledge of MMA anatomy is crucial for its preservation during bypass surgery.

Delayed cerebral ischemia (DCI) occurs several days after subarachnoid hemorrhage (SAH) and could therefore be mitigated by treatment intervention. As testament to the great challenge of designing effective trials, however, the prevalence and severity of DCI have remained unchanged for decades. A critical need in the development of novel prophylactic treatments is optimizing initial prediction for DCI, since improved risk stratification based on prognosis could increase the statistical power of randomized trials, thereby increasing the probability of success and reducing costs. The primary objective of this study, using secondary analysis of data from the DISCHARGE-1 trial, was to evaluate the power of initial variables (medical history, clinical examination, and pre-interventional CT) for predicting the volume of delayed infarcts in SAH survivors. In multivariate analysis of 164 early survivors with pre-interventional CT within 72 h of the initial hemorrhage, the modified Hijdra scale (mHS; β = -0.016, p < 0.001) was the only independent predictor of infarct volume due to DCI, outperforming common clinical scores und manually segmented hemorrhage volumes. Furthermore, early brain injury (EBI) volume identified high-risk patients for early death early on. Thus, we propose a combined approach using mHS and EBI volume for early risk stratification in randomized trials targeting DCI.

ABSTRACT Background Sex differences in cerebrovascular disease are established determinants of outcome in acute stroke care and vascular interventions, but evidence in cerebrovascular bypass surgery remains limited. This study examined whether biological sex was associated with outcome after superficial temporal artery to middle cerebral artery (STA-MCA) bypass in patients with atherosclerotic cerebrovascular disease (ACVD). Methods We retrospectively screened adults undergoing extracranial-to-intracranial (EC-IC) bypass (2012–2025) and included ACVD patients treated by STA-MCA bypass with available follow-up. The primary outcome was modified Rankin Scale (mRS) at latest follow-up, analyzed using proportional odds regression. Multivariable models adjusted for age, preoperative mRS, and vascular comorbidities. Cerebrovascular reserve capacity (CVRC) was analyzed in a subgroup. Results A total of 140 patients (30.7% female) were included. Disease morphology varied by sex, with more multivessel (65.1% vs. 47.4%) and stenotic disease (39.5% vs. 20.6%) in females and more isolated internal carotid artery occlusion in males (43.3% vs. 16.3%). The 30-day risk of symptomatic ischemic stroke was higher in females than in males (9.3% vs. 1.0%). A similar pattern was observed at follow-up (median 13.5 months), with ischemic events predominating in females (16.3% vs. 7.2%) and hemorrhagic events occurring exclusively in males (5.2%). Female sex was independently associated with worse functional outcome (OR 2.59, 95% CI 1.28–5.30, p=0.008). Preoperative mRS was the strongest determinant of outcome (OR 4.30, 95% CI 3.07–6.18, p<0.001). Adjusted analysis detected no significant association between CVRC and outcome (OR 0.80, 95% CI 0.24–2.70, p=0.721). Conclusions Female sex was independently associated with worse functional outcome after STA-MCA bypass, independent of preoperative functional status, hemodynamic impairment and cardiovascular comorbidities. These findings identify sex as a clinically relevant determinant of outcome in cerebrovascular bypass surgery and should be considered in future risk stratification and trial design.

The glymphatic system facilitates cerebrospinal fluid (CSF)–interstitial fluid exchange and plays a key role in solute clearance and neurophysiological homeostasis. While dysfunction of this system has been shown in traumatic brain injury, stroke, meningitis, idiopathic normal pressure hydrocephalus and neurodegenerative diseases, direct measurement of glymphatic transport in humans remains elusive. We propose microGLYMPH as a translational, hypothesis-generating framework that combines established clinical cerebral microdialysis with controlled CSF tracer administration via existing clinical access routes, including an external ventricular drain, cisternal access during surgery, or lumbar intrathecal injection when clinically justified. The aim is to obtain time-resolved regional tracer profiles in microdialysate and to interpret these alongside arousal state, intracranial dynamics, and, where available, complementary imaging, thereby providing an indirect measure of CSF–interstitial exchange kinetics and peripheral tracer appearance. We further define the key design, analytical and practical limitations that must be resolved before the approach can extend beyond exploratory use, notably catheter-adjacent effects, blood–brain barrier disruption, drainage practices, and the intrinsically focal nature of microdialysis. microGLYMPH is therefore intended as a staged roadmap for first-in-human feasibility studies and subsequent hypothesis-driven investigations of neurofluid solute transport after acute brain injury.

OBJECTIVE:Although minimally invasive techniques are established in thoracolumbar spine surgery, their benefit and applicability in cervical spine surgery still require further validation. This study aimed to investigate feasibility and screw accuracy, as well as paraspinal muscle atrophy, in the authors' initial patient cohort of subaxial percutaneous navigated cervical screw-rod instrumentation through a retrospective matched-patient analysis. METHODS:The patients of the percutaneous group (PG) (n = 20) were matched with the patients of the conventional group (CG) who underwent the midline approach (n = 20) on the basis of total instrumented segments, level of instrumentation, age, and sex. Pedicle screw accuracy was assessed using the Bredow classification and cross-sectional muscle areas were compared preoperatively and at a minimum follow-up of 60 days. RESULTS:Surgical indications were primarily degenerative in the CG (70%) and more diverse in the PG (40% degenerative, 35% oncological, and 20% traumatic). The percutaneous system was more frequently used in combined anterior-posterior approaches (50% PG vs 35% CG). Skin incision to navigation time was significantly shorter in the PG (mean ± SD 14 ± 15 minutes vs 44 ± 23 minutes in the CG), while screw placement time and clinically acceptable postoperative screw accuracy (88% PG vs 95% CG) were comparable. After a median follow-up of 140 days, muscle area change was without relevant differences (99.1% PG vs 93.7% CG), and no neurovascular injuries occurred in either group. CONCLUSIONS:Percutaneous cervical screw-rod instrumentation using navigated pedicle screws is a versatile tool offering comparable accuracy. Besides the advantages of shorter preparation time and applicability in combined approaches, the real benefits of muscle preservation need to be proven in larger prospective patient cohorts.

PURPOSE:Robot-assisted, monoplane C-arm angiography systems designed for hybrid operating rooms represent an alternative approach to neuroendovascular procedures. Conversely, non-computer-assisted monoplane systems or conventional biplane systems in angiography suites are widely established. This study aims to evaluate the effectiveness, safety and efficiency of a robotic C-arm angiography system in performing neuroendovascular interventions, including cerebrovascular digital subtraction angiography (DSA), embolization of the middle meningeal artery (MMA) in subdural hematoma, and mechanical thrombectomy for vessel occlusion. METHODS:All patients undergoing DSA, MMA embolization, or mechanical thrombectomy between July 2020 and December 2024 were retrospectively included. Procedures were performed using a monoplane robotic C-arm system (ARTIS pheno, Siemens Healthineers, Munich, Germany) in a hybrid operating room. Clinical data, procedural details, and imaging outcomes were analyzed. Radiation exposure was assessed by fluoroscopy time, air kerma, and dose-area product (DAP). RESULTS:A total of 49 procedures were analyzed, including 28 DSAs, 6 MMA embolizations, and 15 mechanical thrombectomies. DSA and MMA embolization (EMMA grade ≥2) achieved 100% procedural success, while mechanical thrombectomies achieved successful reperfusion (mTICI ≥2b) in 93.3% of cases. Median procedure durations were 34.0 (IQR 18.0-45.0) minutes for DSA, 70.0 (IQR 28.0-126.0) minutes for MMA embolization, and 84.0 (IQR 67.0-106.0) minutes for mechanical thrombectomy. Median fluoroscopy times were 5.2 (IQR 2.9-11.5) minutes (DSA), 21.3 (IQR 8.8-36.5) minutes (MMA embolization), and 21.2 (IQR 18.5-42.9) minutes (mechanical thrombectomy). Median DAPs were 7262.5 (IQR 3867.8-11570.8) µGy·m² (DSA), 16135.5 (IQR 8244.2-18216.2) µGy·m² (MMA embolization), and 9875.2 (IQR 6524.3-18455.5) µGy·m² (mechanical thrombectomy). Additional 3D-angiography or cone-beam CT (CBCT) was associated with higher radiation exposure. CONCLUSION:Basic neuroendovascular procedures can be safely and efficiently performed using a monoplane robotic C-arm in a hybrid operating room, achieving procedural success and radiation exposure levels comparable to conventional biplane systems.

Introduction:Obese patients are often advised to lose weight before spinal surgery to improve postoperative outcomes. However, pain-related functional limitations make preoperative weight reduction unfeasible. In this context, it would be expected that postoperative pain relief facilitates subsequent weight reduction. Thus, the objective of this study was to examine whether a positive clinical response to mono- or bisegmental lumbar fusion for degenerative indications is associated with body-weight change during long-term follow-up. Methods:In this retrospective study, 53 obese patients (BMI ≥30) who underwent spinal fusion surgery between 2020 and 2022 were analyzed. A positive response was defined as a reduction of ≥2 points on the visual analog scale (VAS) for back pain. Patients were divided into responders (R; n = 33) and non-responders (NR; n = 20). Results:Baseline characteristics showed no significant difference. Mean follow-up was 3.5 years. Overall, BMI decreased from 34 ± 4 to 33 ± 5 (p = 0.002), corresponding to a mean weight reduction from 100 ± 18 kg to 97 ± 21 kg (p = 0.003). In subgroup analyses, a significant BMI decrease of 7% was observed in the NR group (p = 0.004), whereas no statistically significant BMI change was observed in the R group. Conclusion:Postoperative pain relief did not appear to be associated with long-term weight loss in this cohort. These findings suggest that key factors other than pain relief may influence physical activity and weight change in obese patients following spinal fusion.

Abstract Background External ventricular drainage (EVD)-associated ventriculitis is a serious complication in neurocritical care. Diagnostic uncertainty and heterogeneous infection prevention and control (IPC) practices may contribute to variable ventriculitis rates and potentially avoidable antibiotic exposure. We evaluated the impact of implementing an interdisciplinary standard operating procedure (SOP) on ventriculitis incidence and antimicrobial stewardship (ABS)-related outcomes. Methods We conducted a retrospective single-centre pre–post study in one intensive care unit (ICU) at Charité–Universitätsmedizin Berlin (2019–2023). Adult patients with EVDs were assigned to a pre-SOP cohort (Group 1) or a post-SOP cohort (Group 2). The SOP comprised standardized IPC protocols, an algorithm-based diagnostic workup and evidence-based anti-infective strategies. The primary endpoint was study-defined EVD-associated ventriculitis, adjudicated retrospectively using uniform criteria. Secondary endpoints included empirical antibiotic initiation, duration of therapy, antibiotic consumption, ICU length of stay (LOS), mortality, and SOP adherence. Cerebrospinal fluid (CSF) parameters and clinical signs were summarized descriptively. Results A total of 166 patients were included (pre-SOP, Group 1: n = 50; post-SOP, Group 2: n = 116). The study-defined ventriculitis rate decreased from 22% [95% CI 0.13–0.35] to 9.5% [95% CI 0.05–0.16] with an unadjusted OR 0.37 [95% CI 0.13–1.04]; p = 0.053, attenuated with an adjusted OR of 0.50 [95% CI 0.19–1.35]; p = 0.169. Incidence density declined from 21.1 to 12.0 per 1000 EVD days. Empirical antibiotic use fell from 28.0% [95% CI 17.5–41.7] to 12.9% [95% CI 8.0–20.2], corresponding to an unadjusted OR of 0.38 [95% CI 0.17–0.87] and median therapy duration decreased from 16 [95% CI 13.5–18.5] to 10 days [95% CI 6.5–13.5]. ICU LOS shortened by 4 days, while ICU mortality remained unchanged (26% vs. 27%). Conclusion An interdisciplinary SOP was associated with reduced empirical antibiotic exposure and shorter treatment duration without affecting ICU mortality. The SOP appeared to improve diagnostic consistency and standardization of the workup rather than diagnostic test performance. Trial registration The study is registered in the German Clinical Trial Register (DRKS ID: 00036075) in February 2025.

Introduction:Minimally invasive posterior cervical fixation remains technically challenging due to narrow pedicle dimensions and proximity to neurovascular structures. This multicenter study evaluates the accuracy and safety of a dedicated minimally invasive cervical pedicle screw-rod system with 3D navigation guidance. Research question:Can minimally invasive cervical pedicle screw placement achieve accuracy rates comparable to open techniques while maintaining patient safety? Material and methods:Retrospective multicenter analysis of 46 patients (60.7 ± 17.4 years) undergoing percutaneous cervical pedicle screw-rod instrumentation at three German university centers (01/2022-04/2024). Indications included degenerative disease (n = 21), tumors (n = 13), trauma (n = 8), and inflammation (n = 4). Primary outcome was neurological status (Frankel classification); secondary outcomes included screw accuracy (Bredow classification), surgical characteristics, and complications. All procedures utilized 3D navigation based on cone-beam CT or intraoperative CT. Results:In total, 232 pedicle screws were implanted from C2 to T2. Favorable screw position (Bredow grades 1-2) was achieved in 89.7% overall, with significantly lower accuracy at C3-C6 versus other levels (86.0% vs. 95.4%, p = 0.0297). No permanent neurological deficits occurred. Two screws required intraoperative repositioning; zero revision surgeries were needed. Mean surgical duration was 148 ± 66min with blood loss of 236 ± 183 ml. Discussion and conclusion:Minimally invasive cervical pedicle screw-rod instrumentation with 3D navigation achieves high accuracy and safety comparable to open techniques. In the majority of cases, the technique supplemented anterior fusion for additional stability, but it may also serve as posterior-only instrumentation for in tumor-related osteolysis or traumatic injuries. Mid-cervical levels remain particularly challenging and require heightened vigilance.

BACKGROUND:Continuous, wearable-based vital sign monitoring can enhance patient safety and reduce intensive care demands but is not routinely used on standard neurosurgical wards. This study assessed alarm events and technology acceptance during the implementation of such a system for postoperative patients in a university hospital's neurosurgical ward. METHODS:In this pilot feasibility study, selected patients were continuously monitored for 12 to 24 hours after elective neurosurgery on a 44-bed ward. Phase 1 (June to December 2019) used 12 mobile units with manual alarm documentation; Phase 2 (August 2023 to January 2024) used 44 fixed bedside units with automatic documentation. Alarm patterns and nurse-rated technology acceptance (4-point Likert scale) were analyzed. RESULTS:Vital signs were monitored in 214 patients (median age: 58, IQR: 42 to 70) in Phase 1 and 290 patients (median age: 60, IQR: 43 to 77) in Phase 2. Procedures included cranial, spinal, and peripheral nerve surgeries. Phase 1 recorded 30 nonclinical alarms and no clinical alarms. In contrast, Phase 2 registered 14,500 clinical and 185,744 nonclinical alarms, mostly from detached sensors (177,989/185,744; 96%). Clinical alarms were mainly due to hypoxia (8305/14,500; 57%) and tachycardia (3487/14,500; 30%). Most alarms were acknowledged within 30 seconds (clinical: 12,969/14,500; 90% and nonclinical: 181,447/185,744; 98%), with delayed responses mostly for nonclinical events (3625/4189; 87%). Nurses reported improved convenience, usability, and system connection in Phase 2. CONCLUSIONS:Wearable-based vital sign monitoring is feasible on neurosurgical wards, but high nonclinical alarm rates highlight the need to refine alarm management strategies for effective clinical integration.

Study Design.Retrospective study.Objective.Lumbar spinal stenosis (LSS) is known as one of the most frequent causes of spinal surgery. Since sagittal balance (SB) has drawn scientific attention in recent years, questions have been raised, as to whether there is a need to restore SB for the best clinical outcome in every spinal surgery. This study evaluated the influence of SB on the clinical outcome of patients with LSS in a long-term follow-up of more than 4 years.Background.Results of short-term follow-up did not show any association between clinical outcome and the degree of sagittal imbalance in patients with LSS, who received microsurgical decompression alone. Data concerning the long-term influence of SB are lacking.Patients and Methods.A total of 136 patients were included and received a 1-year follow-up. Seventy-two subjects underwent additional long-term follow-up (51 mo). The patients received preoperative and follow-up long-standing spinal radiographs. Patients were assigned to one of 3 groups, according to their SB [normal balance, minor loss of balance (miIB), and major loss of balance]. Clinical outcome parameters were determined by evaluating the Roland-and-Morris Disability Questionnaire, Oswestry-Disability-Index, Odom criteria, Short Form 36-item score, Visual Analog Scales for pain, and walking distance.Results.Long-term follow-up showed a significant improvement of clinical outcome parameters independently of their SB [triangle Oswestry Disability Index (ODI)_normal balance = -23.0 +/- 18.9; triangle ODI_miIB = - 26.9 +/- 21.6; triangle ODI_major loss of balance = -21.6 +/- 25.1]. There was no significant difference among the 3 groups in pain, disability, and quality of life. The miIB group benefitted most concerning walking distance. A relevant change concerning the SB was not detected at 4 years after surgery.Conclusions:SB does not influence the long-term clinical outcome in patients with symptomatic LSS after microsurgical decompression. Patients without obvious instability benefit significantly from microsurgery, regardless of their preoperative global SB. The initial pathologic SB in patients with LSS appears to represent true structural changes of the spine, rather than a pseudo-imbalance due to a compensatory mechanism to relieve claudication.

Spreading depolarization (SD) describes a propagating neuronal mass depolarization within the cerebral cortex that represents a mediator of infarct development and strongly stimulates the metabolic rate of O2 consumption. Here, we investigated the influence of spreading depolarization on brain tissue partial pressure of O2 (ptiO2) within the peri-infarct tissue of patients suffering malignant hemispheric stroke. This prospective observational trial included 25 patients with malignant hemispheric stroke that underwent decompressive hemicraniectomy followed by subdural placement of electrodes for electrocorticography (ECoG) and neighbouring implantation of a ptiO2 probe within the peri-infarcted cortex. Continuous side-by-side ECoG + ptiO2 recordings were obtained for 3-6 days postoperatively and analysed for the occurrence of SD-independent and SD-coupled ptiO2 changes, radiological findings, as well as their association with clinical outcome at 6 months. During the combined ECoG + ptiO2 monitoring period of 2604 h and among 1022 SDs, 483 (47%) SD-coupled ptiO2 variations were identified as biphasic (59%), hypoxic (36%) or hyperoxic (5%) ptiO2 responses that differed significantly (P < 0.0001). Among the remaining 538/1022 (53%) SDs, no SD-coupled ptiO2 response was detected, which we categorized as 'No response'. The overall infarct progression was 1.7% (interquartile range -2.5-10.9). SD characteristics regarding type, duration and frequency, as well as SD-independent baseline ptiO2 had no association with outcome. In contrast, a high occurrence rate and amplitude of SD-coupled variations in ptiO2 were associated with improved outcome at 6 months (occurrence: r = -0.62, P = 0.035; amplitude: r = -0.57, P = 0.024; Spearman correlation). In conclusion, an absent or reduced ptiO2 response to SD could indicate tissue-at-risk and help direct targeted treatment strategies in ischaemic stroke, which is further evidence that not all SDs are the same but tissue responses coupled to SD such as ptiO2 contain prognostic information. In particular, a lack of SD-coupled ptiO2 variations appears to be a predictor of worse outcome in large hemispheric stroke.

Chronic subdural hematoma (cSDH) is a highly prevalent condition that frequently requires surgical evacuation. This is typically achieved through burr hole evacuation, which can be performed under either local anesthesia (LA) or general anesthesia (GA). In the present study, we provide a systematic review and meta-analysis to study and compare the safety and efficacy of cSDH evacuation in LA and GA. Following the PRISMA guidelines, we screened four databases for studies that compared postoperative outcomes after burr hole evacuation of cSDH in LA versus GA. Baseline characteristics and postoperative outcome data were collected, and risk ratios were calculated for each study as well as pooled across records. Random effect models were applied to continuous data points. Bias was assessed using the MINORS tool. We identified 22 eligible studies covering 3917 patients in total. LA was associated with decreased risk for complications (p < 0.001), shorter surgery duration (p < 0.001) and hospital stay (p < 0.001). There was no statistically significant association with recurrence rates, postoperative seizure or occurrence of pneumocephalus. In a subanalysis including only data from studies utilizing subdural drainage, results remained largely similar with LA proving advantageous in terms of shorter surgery duration (p < 0.001) and hospital stay (p < 0.001). LA may serve as a safe alternative to GA for cSDH surgery, associated with fewer postoperative complications and providing benefits regarding shorter hospital stay and surgery duration.

OBJECTIVE:This study aims to evaluate clinical and radiological outcomes of patients with atlantoaxial instability treated with stand-alone atlas (C1)-axis (C2) lateral mass/pedicle/pars screw-rod instrumentation without supplemental grafting materials. METHODS:Between July 2014 and January 2022, data from 64 adults undergoing stand-alone, navigated posterior C1-C2 screw-rod fixation were retrospectively collected. Radiological outcome assessment involved cervical computer tomography scans and X-ray radiographs evaluating osseous intervertebral fusion and implant failure. Clinical outcome assessment included patient-reported outcome measures encompassing pain levels using the numeric pain rating scale, patient satisfaction according to Odom criteria, and pain-related disability in activities of daily life by the neck disability index (NDI). RESULTS:Radiological outcome evaluation revealed progressive osseous fusion over time with 100% fusion achieved at follow-up (mean: 12.3 ± 15.4 months) and low overall rates of implant failure (3.1%). Clinical outcome evaluation demonstrated mild pain levels (median numeric pain rating scale: 2), good patient satisfaction (median Odom criteria: 2), and moderate neck disability (median NDI/NDI%: 11/22.2%), which remained stable over a mean follow-up time of 29 ± 16.6 months. CONCLUSION:Stand-alone C1-C2 lateral mass/pedicle/pars screw-rod instrumentation without grafting is a viable option for treatment of atlantoaxial instability. This technique offers favorable clinical and radiological outcomes while avoiding complications associated with grafting.

Introduction:Intraoperative ultrasound (IOUS) has gained recognition as a valuable imaging modality for enhancing surgical precision in neurosurgical procedures. However, its routine clinical integration in spine surgery remains limited. Research question:This study aims to elucidate role of intraoperative ultrasound (IOUS) in spinal surgery and to propose the Spinal Cord Pulsatility Index (SCPI) as a novel, ultrasound-based parameter for evaluating spinal cord decompression. Material and methods:This retrospective single-center case series included all consecutive patients who underwent spinal surgery with IOUS guidance between June 2024 and January 2025. In a subset of patients undergoing posterior decompression, the SCPI - defined as the ratio between the spinal cord pulsation and the corresponding heart rate - was calculated. Results:Overall, IOUS was performed in 28 patients, and 3 main IOUS applications were determined: (1) anatomic localization, (2) augmentive use, and (3) spinal cord decompression assessment. Importantly, IOUS was fast and technically feasible in all cases, across regions of the spine and regardless of the surgical approach. In a subset of n = 8 cases, we noted a significant SCPI increase at the time-point of final decompression (*p < 0.05). Discussion and conclusion:IOUS in spinal surgery serves as a simple, safe, cost-effective, and non-invasive imaging modality for real-time localization of intradural and intramedullary pathologies and supplementary neurovascular structures. Based on the principle of communicating fluid dynamics, the spinal cord pulsation index may serve as a novel parameter for indirect assessment of sufficient spinal cord decompression beyond the levels of surgical exposure.

Brain metastases (BrMs) may present with intralesional or intracranial hemorrhage (ICH), yet risk factors and outcomes remain unclear. This monocentric cohort study at Germany's largest neurosurgical clinic included 973 adults undergoing BrM resection (2010–2024), with histopathologically confirmed etiologies and known tumor burden. Based on pre‐operative CT or MRI, 880 patients were categorized as non‐hemorrhagic (non‐hBrM), presenting with intralesional hemorrhage (hBrM), or with ICH of ≥30 mm diameter (ICH‐BrM). Risk factors for hBrM and ICH‐BrM were assessed, and overall survival (OS) and progression‐free survival (PFS) were analyzed using Kaplan‐Meyer methods. Of 880 patients, 560 (63.6%) were non‐hBrM, 243 (27.6%) hBrM, and 77 (8.8%) ICH‐BrM. ICH‐BrM had larger tumor volume (21 cm 3 , IQR 13–34) than hBrM (14 cm 3 , IQR 6–28) and non‐hBrM (12 cm 3 , IQR 6–21) ( p adjust = .017), correlated with lower post‐op Karnofsky index ( p adjust = .047), dsGPA score ( p adjust = .032), and more BrMs ( p adjust = .004). Pre‐operative antithrombotic use did not differ between groups ( p adjust = .32). Melanoma was more common in hBrM (27.8%) and ICH‐BrM (38.0%), predicting ICH (OR 2.95, p < .001) along with NSCLC (OR 1.64, p < .001). ICH did not independently predict worse OS (HR 1.23, p = .38). Worse OS was linked to larger tumor volume (HR 1.35, p = .002), extracranial metastases (HR 1.77, p < .001), and older age (HR 1.53, p < .001), while KPS >80% (HR 0.77, p < .01), solitary BrM (HR 0.62, p = .002), and adjuvant treatments ( p < .001) predicted improved OS. ICH is associated with larger tumors and melanoma but is not an independent OS predictor. Tumor burden, extracranial metastases, and adjuvant treatments drive BrM survival.

Accurate assessment of spinopelvic alignment is essential for managing adult spinal deformities. This study validates the Brainlab Elements Spine Planning software for automated measurement of spinopelvic parameters, comparing it with manual methods. Spinopelvic parameters were measured manually and with the software in 21 patients with degenerative spinal disease, including instrumented and non-instrumented spines. Accuracy, intraobserver, and interobserver reliability were evaluated using Bland–Altman plots and intraclass correlation coefficients (ICCs). Measurement times were also compared. The software showed high reliability (ICC = 1), while manual measurements ranged from fair to excellent reliability (ICC 0.44–0.99). Bland–Altman plots indicated strong agreement between automated and manual measurements, though variability was noted for certain parameters. Automated measurements were significantly faster, averaging 62 s versus 227 s in manual measurements (p < 0.001), though 76.2