Cerebral physiologic insult burden in acute traumatic neural injury: a Canadian High Resolution-TBI (CAHR-TBI) descriptive analysis.

BACKGROUND: Over the recent decades, continuous multi-modal monitoring of cerebral physiology has gained increasing interest for its potential to help minimize secondary brain injury following moderate-to-severe acute traumatic neural injury (also termed traumatic brain injury; TBI). Despite this heightened interest, there has yet to be a comprehensive evaluation of the effects of derangements in multimodal cerebral physiology on global cerebral physiologic insult burden. In this study, we offer a multi-center descriptive analysis of the associations between deranged cerebral physiology and cerebral physiologic insult burden. METHODS: Using data from the Canadian High-Resolution TBI (CAHR-TBI) Research Collaborative, a total of 369 complete patient datasets were acquired for the purposes of this study. For various cerebral physiologic metrics, patients were trichotomized into low, intermediate, and high cohorts based on mean values. Jonckheere-Terpstra testing was then used to assess for directional relationships between these cerebral physiologic metrics and various measures of cerebral physiologic insult burden. Contour plots were then created to illustrate the impact of preserved vs impaired cerebrovascular reactivity on these relationships. RESULTS: It was found that elevated intracranial pressure (ICP) was associated with more time spent with cerebral perfusion pressure (CPP) < 60 mmHg and more time with impaired cerebrovascular reactivity. Low CPP was associated with more time spent with ICP > 20 or 22 mmHg and more time spent with impaired cerebrovascular reactivity. Elevated cerebrovascular reactivity indices were associated with more time spent with CPP < 60 mmHg as well as ICP > 20 or 22 mmHg. Low brain tissue oxygenation (PbtO2) only demonstrated a significant association with more time spent with CPP < 60 mmHg. Low regional oxygen saturation (rSO2) failed to produce a statistically significant association with any particular measure of cerebral physiologic insult burden. CONCLUSIONS: Mean ICP, CPP and, cerebrovascular reactivity values demonstrate statistically significant associations with global cerebral physiologic insult burden; however, it is uncertain whether measures of oxygen delivery provide any significant insight into such insult burden.

The prognostic role of preoperative neutrophil-to-lymphocyte ratio in upper tract urothelial carcinoma.

Introduction: The blood-based inflammatory marker, neutrophil-to-lymphocyte ratio (NLR), is a reliable prognostic biomarker for several cancers. Although the literature supports the correlation between preoperative NLR, clinicopathological characteristics, and oncological outcomes in upper tract urothelial carcinoma (UTUC), the cutoff of NLR is still debated. This study aimed to determine the prognostic value of NLR in patients with UTUC. Methods: This was a retrospective analysis of prospectively collected data from July 2012 to December 2022 evaluating patients with UTUC who underwent radical nephroureterectomy (RNU). NLR was calculated using the neutrophil and lymphocyte counts obtained a day before the surgery and the cutoff value was set as 2.5. Kaplan-Meier and Cox's proportional hazards regression were used to analyze the association between NLR and the oncological outcomes. Results: The study included 91 patients (78 males, 13 females) in the final analysis with a median follow-up of 49 months (8-130). The mean age of the patients with NLR <2.5 and NLR ≥2.5 was 56.88 years and 56.35 years, respectively, and the pathological stage was pT1 in 48%, pT2 in 20.88%, pT3 in 27.47%, and pT4 in 3.30% of the patients. Multivariable Cox regression analysis showed that the preoperative NLR ≥2.5 was significantly associated (Hz = 7.17) with higher T stage, lymphovascular invasion, necrosis, nodal involvement, adjuvant chemotherapy, and worse overall survival (OS) (Hz = 9.87). The Kaplan-Meier analysis revealed an improved OS in patients with NLR <2.5, but a statistically significant difference in the recurrence-free survival was not found. Conclusions: Preoperative NLR is an easily available, inexpensive, and important prognostic biomarker of survival in patients with UTUC and has a potential role in risk stratification by predicting adverse clinicopathological characteristics.

Delayed Cerebral Infarction After Aneurysmal Subarachnoid Hemorrhage: Location, Distribution Patterns, Infarct Load, and Effect on Outcome.

BACKGROUND AND OBJECTIVES: Delayed cerebral ischemia (DCI) is one of the main contributing factors to poor clinical outcome after aneurysmal subarachnoid hemorrhage (SAH). Unsuccessful treatment can cause irreversible brain injury in the form of DCI-related infarction. We aimed to assess the association between the location, distribution, and size of DCI-related infarction in relation to clinical outcome. METHODS: Consecutive patients with SAH treated at 2 university hospitals between 2014 and 2019 (Helsinki, Finland) and between 2006 and 2020 (Aachen, Germany) were included. Size of DCI-related infarction was quantitatively measured as absolute volume (in milliliters). In a semiquantitative fashion, infarction in 14 regions of interest (ROIs) according to a modified Alberta Stroke Program Early CT Score (ASPECTS) was noted. The association of infarction in these ROIs along predefined regions of eloquent brain, with clinical outcome, was assessed. For this purpose, 1-year outcome was measured by the Glasgow Outcome Scale (GOS) and dichotomized into favorable (GOS 4-5) and unfavorable (GOS 1-3). RESULTS: Of 1,190 consecutive patients with SAH, 155 (13%) developed DCI-related infarction. One-year outcome data were available for 148 (96%) patients. A median overall infarct volume of 103 mL (interquartile range 31-237) was measured. DCI-related infarction was significantly associated with 1-year unfavorable outcome (odds ratio [OR] 4.89, 95% CI 3.36-7.34, p < 0.001). In patients with 1-year unfavorable outcome, vascular territories more frequently affected were left middle cerebral artery (affected in 49% of patients with unfavorable outcome vs in 30% of patients with favorable outcome; p = 0.029), as well as left (44% vs 18%; p = 0.003) and right (52% vs 14%; p < 0.001) anterior cerebral artery supply areas. According to the ASPECTS model, the right M3 (OR 8.52, 95% CI 1.41-51.34, p = 0.013) and right A2 (OR 7.84, 95% CI 1.97-31.15, p = 0.003) regions were independently associated with unfavorable outcome. DISCUSSION: DCI-related infarction was associated with a 5-fold increase in the odds of unfavorable outcome, after 1 year. Ischemic lesions in specific anatomical regions are more likely to contribute to unfavorable outcome. TRIAL REGISTRATION INFORMATION: Data collection in Aachen was registered in the German Clinical Trial Register (DRKS00030505); on January 3, 2023.

Critical thresholds of long-pressure reactivity index and impact of intracranial pressure monitoring methods in traumatic brain injury.

BACKGROUND: Moderate-to-severe traumatic brain injury (TBI) has a global mortality rate of about 30%, resulting in acquired life-long disabilities in many survivors. To potentially improve outcomes in this TBI population, the management of secondary injuries, particularly the failure of cerebrovascular reactivity (assessed via the pressure reactivity index; PRx, a correlation between intracranial pressure (ICP) and mean arterial blood pressure (MAP)), has gained interest in the field. However, derivation of PRx requires high-resolution data and expensive technological solutions, as calculations use a short time-window, which has resulted in it being used in only a handful of centers worldwide. As a solution to this, low resolution (longer time-windows) PRx has been suggested, known as Long-PRx or LPRx. Though LPRx has been proposed little is known about the best methodology to derive this measure, with different thresholds and time-windows proposed. Furthermore, the impact of ICP monitoring on cerebrovascular reactivity measures is poorly understood. Hence, this observational study establishes critical thresholds of LPRx associated with long-term functional outcome, comparing different time-windows for calculating LPRx as well as evaluating LPRx determined through external ventricular drains (EVD) vs intraparenchymal pressure device (IPD) ICP monitoring. METHODS: The study included a total of n = 435 TBI patients from the Karolinska University Hospital. Patients were dichotomized into alive vs. dead and favorable vs. unfavorable outcomes based on 1-year Glasgow Outcome Scale (GOS). Pearson's chi-square values were computed for incrementally increasing LPRx or ICP thresholds against outcome. The thresholds that generated the greatest chi-squared value for each LPRx or ICP parameter had the highest outcome discriminatory capacity. This methodology was also completed for the segmentation of the population based on EVD, IPD, and time of data recorded in hospital stay. RESULTS: LPRx calculated with 10-120-min windows behaved similarly, with maximal chi-square values ranging at around a LPRx of 0.25-0.35, for both survival and favorable outcome. When investigating the temporal relations of LPRx derived thresholds, the first 4 days appeared to be the most associated with outcomes. The segmentation of the data based on intracranial monitoring found limited differences between EVD and IPD, with similar LPRx values around 0.3. CONCLUSION: Our work suggests that the underlying prognostic factors causing impairment in cerebrovascular reactivity can, to some degree, be detected using lower resolution PRx metrics (similar found thresholding values) with LPRx found clinically using as low as 10 min-by-minute samples of MAP and ICP. Furthermore, EVD derived LPRx with intermittent cerebrospinal fluid draining, seems to present similar outcome capacity as IPD. This low-resolution low sample LPRx method appears to be an adequate substitute for the clinical prognostic value of PRx and may be implemented independent of ICP monitoring method when PRx is not feasible, though further research is warranted.

Long-term risk of hemorrhage and mortality after treatment of high-grade intracranial dural arteriovenous fistulas.

BACKGROUND: Despite recent multi-institutional efforts, long-term data on clinical and radiological outcomes after treatment of high-grade dural arteriovenous fistulas (dAVFs) remain scarce. This study aimed to evaluate the long-term risk of hemorrhage and fistula-related mortality after treatment. METHODS: Retrospective analysis of all consecutive patients primarily diagnosed with a high-grade dAVF (Cognard grade 2b, 2a+b, 3, 4) between January 2012 and September 2022 at a large neurovascular center. Primary endpoints were intracranial hemorrhage (ICH) and all-cause mortality after treatment; secondary endpoints were angiographic occlusion, complication rate and neurological deficits. RESULTS: A total of 121 patients underwent 141 treatments (122 endovascular therapy (EVT), 5 radiotherapy, 14 surgery) of which 12 patients (10%) underwent retreatment. Follow-up was available in all patients for a median of 4.2 (IQR 2.5 to 6.6) years. Eleven patients (9%) died during the follow-up period, of which three deaths (2%) occurred after hemorrhagic presentation, one of them attributable to treatment. One death (0.8%) was due to delayed hemorrhage after partial occlusion from EVT. No other post-treatment bleedings occurred. Angiographic follow-up after multimodality treatment was available in 93% of patients after a median of 6 months; the overall occlusion rate was 90%. The overall rate of complications was 25% after EVT and 14% after surgery. The rates of new transient and permanent neurological deficits after EVT were 9% and 3%, respectively. CONCLUSIONS: The long-term rate of re-bleeding or dAVF-related mortality was low when high rates of angiographic occlusion were achieved. The risk for treatment-related complications leading to neurological sequela was low.

Burr-hole drainage with or without irrigation for chronic subdural haematoma (FINISH): a Finnish, nationwide, parallel-group, multicentre, randomised, controlled, non-inferiority trial.

BACKGROUND: Chronic subdural haematoma is a common surgically treated intracranial emergency. Burr-hole drainage surgery, to evacuate chronic subdural haematoma, involves three elements: creation of a burr hole for access, irrigation of the subdural space, and insertion of a subdural drain. Although the subdural drain has been established as beneficial, the therapeutic effect of subdural irrigation has not been addressed. METHODS: The FINISH trial was an investigator-initiated, pragmatic, multicentre, nationwide, randomised, controlled, parallel-group, non-inferiority trial in five neurosurgical units in Finland that enrolled adults aged 18 years or older with a chronic subdural haematoma requiring burr-hole drainage. Patients were randomly assigned (1:1) by computer-generated block randomisation with block sizes of four, six, or eight, stratified by site, to burr-hole drainage either with or without subdural irrigation. All patients and staff were masked to treatment assignment apart from the neurosurgeon and operating room staff. A burr hole was drilled at the site of maximum haematoma thickness in both groups, and the subdural space was either irrigated or not irrigated before inserting a subdural drain, which remained in place for 48 h. Reoperations, functional outcome, mortality, and adverse events were recorded for 6 months after surgery. The primary outcome was the reoperation rate within 6 months. The non-inferiority margin was set at 7·5%. Key secondary outcomes that were also required to conclude non-inferiority were the proportion of participants with unfavourable functional outcomes (ie, modified Rankin Scale score of 4-6, where 0 indicates no symptoms and 6 indicates death) and mortality rate at 6 months. The primary and key secondary analyses were done in both the intention-to-treat and per-protocol populations. The trial was registered with ClinicalTrials.gov (NCT04203550) and is completed. FINDINGS: From Jan 1, 2020, to Aug 17, 2022, we assessed 1644 patients for eligibility and 589 (36%) patients were randomly assigned to a treatment group and treated (294 assigned to drainage with irrigation and 295 assigned to drainage without irrigation; 165 [28%] women and 424 [72%] men). The 6-month follow-up period extended until Feb 14, 2023. In the intention-to-treat analysis, 54 (18·3%) of 295 participants required reoperation in the group assigned to receive no irrigation versus 37 (12·6%) of 294 in the group assigned to receive irrigation (difference of 6·0 percentage points, 95% CI 0·2-11·7; p=0·30; adjusted for study site). There were no significant between-group differences in the proportion of people with modified Rankin Scale score of 4-6 (37 [13·1%] of 283 in the no-irrigation group vs 36 [12·6%] of 285 in the irrigation group; p=0·89) or mortality rate (18 [6·1%] of 295 in the no-irrigation group vs 21 [7·1%] of 294 in the irrigation group; p=0·58). The findings of the primary intention-to-treat analysis were not materially altered in the per-protocol analysis. There were no significant between-group differences in the number of adverse events, and the most frequent severe adverse events were systemic infections (26 [8·8%] of 295 participants who did not receive irrigation vs 22 [7·5%] of 294 participants who received irrigation), intracranial haemorrhage (13 [4·4%] vs seven [2·4%]), and epileptic seizures (five [1·7%] vs nine [3·1%]). INTERPRETATION: We could not conclude non-inferiority of burr-hole drainage without irrigation. The reoperation rate was 6·0 percentage points higher after burr-hole drainage without subdural irrigation than with subdural irrigation. Considering that there were no differences in functional outcome or mortality between the groups, the trial favours the use of subdural irrigation. FUNDING: State Fund for University Level Health Research (Helsinki University Hospital), Finska Läkaresällskapet, Medicinska Understödsföreningen Liv och Hälsa, and Svenska Kulturfonden.

Long-Term Quality of Life After Pediatric Traumatic Brain Injury Treated in the Intensive Care Unit.

BACKGROUND: To examine the long-term health-related quality of life (HRQL) after pediatric traumatic brain injury (TBI) treated in the intensive care unit (ICU). METHODS: This retrospective cohort study was conducted using data from four university hospital ICUs in Finland. Children aged < 18 years with TBI treated in the ICU during 2003 to 2013 were included. Patients alive at the end of 2020 were sent two different HRQL questionnaires 15/16-dimensional (15D/16D) and RAND-36  and questions regarding chronic diseases, socioeconomical status, and the need for health care support. HRQL was defined as poor when the 15D/16D score total score was below the age- and sex-matched mean population score in Finland minus the minimal clinically important difference. RESULTS: A total of 150 of 337 (44%) patients responded (n = 144 15D/16D responses). Median follow-up time was 11 years. Seventy patients (49%) had a poor HRQL according to 15D/16D score. Patients with TBI had significantly poorer 15D scores in every dimension when compared with the matched population mean values. A higher Helsinki CT score, mechanical ventilation, and female sex were associated with poor long-term HRQL according to the 15D/16D. Patients with poor 15D/16D scores also needed significantly more health care services and medications and had more comorbidities than patients with normal scores. A poor 15D/16D score was associated with lower socioeconomic status. CONCLUSIONS: Half of long-term pediatric ICU-treated TBI survivors had poor HRQL 11 years after injury. More severe head computed tomographic findings at admission and female sex associated with poor HRQL.

Effect of mortality prediction models on resource use benchmarking of intensive care units.

PURPOSE: Intensive care requires extensive resources. The ICUs' resource use can be compared using standardized resource use ratios (SRURs). We assessed the effect of mortality prediction models on the SRURs. MATERIALS AND METHODS: We compared SRURs using different mortality prediction models: the recent Finnish Intensive Care Consortium (FICC) model and the SAPS-II model (n = 68,914 admissions). We allocated the resources to severity of illness strata using deciles of predicted mortality. In each risk and year stratum, we calculated the expected resource use per survivor from our modelling approaches using length of ICU stay and Therapeutic Intervention Scoring System (TISS) points. RESULTS: Resource use per survivor increased from one length of stay (LOS) day and around 50 TISS points in the first decile to 10 LOS-days and 450 TISS in the tenth decile for both risk scoring systems. The FICC model predicted mortality risk accurately whereas the SAPS-II grossly overestimated the risk of death. Despite this, SRURs were practically identical and consistent. CONCLUSIONS: SRURs provide a robust tool for benchmarking resource use within and between ICUs. SRURs can be used for benchmarking even if recently calibrated risk scores for the specific population are not available.

Changes in treatment of intracranial aneurysms during the last decade in a large European neurovascular center.

OBJECTIVE: Treatment modality for ruptured and unruptured intracranial aneurysms has shifted during the last two decades from microsurgical treatment towards endovascular treatment. We present how this transition happened in a large European neurovascular center. METHODS: We conducted a retrospective observational study consecutive patients treated for an unruptured or ruptured intracranial aneurysm at Helsinki University Hospital during 2012-2022. We used Poisson regression analysis to report age-adjusted treatment trends by aneurysm location and rupture status. RESULTS: A total of 2491 patients with intracranial aneurysms were treated (44% ruptured, 56% unruptured): 1421 (57%) surgically and 1070 (43%) endovascularly. A general trend towards fewer treated aneurysms was noted. The proportion of patients treated surgically decreased from 90% in 2012 to 20% in 2022. The age-adjusted decrease of surgical versus endovascular treatment was 6.9%/year for all aneurysms, 6.8% for ruptured aneurysms, and 6.8% for unruptured aneurysms. The decrease of surgical treatment was most evident in unruptured vertebrobasilar aneurysms (10.8%/year), unruptured communicating artery aneurysms (10.1%/year), ruptured communicating artery aneurysms (10.0%/year), and ruptured internal carotid aneurysms (9.0%/year). There was no change in treatment modality for middle cerebral artery aneurysms, of which 85% were still surgically treated in 2022. A trend towards an increasing size for treated ruptured aneurysms was found (p = 0.033). CONCLUSION: A significant shift of the treatment modality from surgical to endovascular treatment occurred for all aneurysm locations except for middle cerebral artery aneurysms. Whether this shift has affected long-term safety and patient outcomes should be assessed in the future.

Prognostic value of near-infrared spectroscopy regional oxygen saturation and cerebrovascular reactivity index in acute traumatic neural injury: a CAnadian High-Resolution Traumatic Brain Injury (CAHR-TBI) Cohort Study.

BACKGROUND: Near-infrared spectroscopy regional cerebral oxygen saturation (rSO2) has gained interest as a raw parameter and as a basis for measuring cerebrovascular reactivity (CVR) due to its noninvasive nature and high spatial resolution. However, the prognostic utility of these parameters has not yet been determined. This study aimed to identify threshold values of rSO2 and rSO2-based CVR at which outcomes worsened following traumatic brain injury (TBI). METHODS: A retrospective multi-institutional cohort study was performed. The cohort included TBI patients treated in four adult intensive care units (ICU). The cerebral oxygen indices, COx (using rSO2 and cerebral perfusion pressure) as well as COx_a (using rSO2 and arterial blood pressure) were calculated for each patient. Grand mean thresholds along with exposure-based thresholds were determined utilizing sequential chi-squared analysis and univariate logistic regression, respectively. RESULTS: In the cohort of 129 patients, there was no identifiable threshold for raw rSO2 at which outcomes were found to worsen. For both COx and COx_a, an optimal grand mean threshold value of 0.2 was identified for both survival and favorable outcomes, while percent time above - 0.05 was uniformly found to have the best discriminative value. CONCLUSIONS: In this multi-institutional cohort study, raw rSO2was found to contain no significant prognostic information. However, rSO2-based indices of CVR, COx and COx_a, were found to have a uniform grand mean threshold of 0.2 and exposure-based threshold of - 0.05, above which clinical outcomes markedly worsened. This study lays the groundwork to transition to less invasive means of continuously measuring CVR.

Initial Experiences with the Trenza Embolization Device for the Treatment of Wide-Neck Intracranial Aneurysms: A 12-Patient Case Series.

The Trenza embolization device is a frame coil implant with flow-disruption properties and is a new alternative to treat challenging mid-to-large-sized broad-neck bifurcation or sidewall aneurysms. We conducted an observational single-center retrospective study of 12 consecutive patients treated for 10 unruptured and 2 ruptured 6- to 12-mm broad-neck bifurcation or sidewall aneurysms with the Trenza device during 2022-2023. The median patient age was 64 years (interquartile range, 59-70 years), 58% were women, the median largest aneurysm diameter was 9.6 mm (interquartile range, 7.5-11.9 mm), the median dome-to-neck ratio was 1.8 (interquartile range, 1.6-1.9), the most common aneurysm locations were the anterior communicating artery (33%) and basilar artery tip (33%). After a median follow-up of 6.5 months, adequate aneurysm occlusion was achieved in 83%. There were 3 major ischemic complications (25%), leading to 2 permanent neurologic deficits (17%) and 1 transient neurologic deficit (8%). There was 1 fatal rupture of a treated aneurysm 1.6 months after the index treatment. Two patients were retreated (17%). Ischemic complications occurred in patients after a too-dense coil packing at the base of the aneurysm. No technical issues related to the device were encountered. In summary, an adequate aneurysm occlusion rate was achieved using the Trenza-assisted coiling technique for otherwise challenging mid-to-large-sized broad-neck aneurysms. Ischemic complications seemed to occur following overdense coiling at the base of the aneurysm.

Digital exoscope versus surgical microscope in spinal dural arteriovenous fistula surgery: a comparative series.

OBJECTIVE: Surgical treatment of spinal dural arteriovenous fistulas (DAVFs) has been reported to be superior to endovascular treatment in terms of occlusion of the fistula. Despite the increased availability of digital 3D exoscopes, the potential benefits of using an exoscope in spinal DAVF surgery have not been studied. The purpose of this study was to report and compare the results of exoscope- and microscope-assisted surgery for spinal DAVFs. METHODS: All consecutive adult patients (≥ 18 years of age) treated surgically for spinal DAVFs from January 2016 to January 2023 in a tertiary neurosurgical referral center were included. All patients were operated on by one neurosurgeon. Their pre- and postoperative clinical findings, imaging studies, and intra- and postoperative events were evaluated and surgical videos from the operations were analyzed. RESULTS: Altogether, 14 patients received an operation for spinal DAVF during the study period, 10 (71%) with an exoscope and 4 (29%) with a microscope. The DAVFs were most commonly located in the lower parts of the thoracic spine in both groups. The duration of exoscopic surgeries was shorter (141 vs 151 minutes) and there was less blood loss (60 vs 100 ml) than with microscopic surgeries. No major surgical complications were observed in either group. Of the 14 patients, 10 had gait improvement postoperatively: 7 (78%) patients in the exoscope group and 3 (75%) in the microscope group. None of the patients experienced deterioration following surgery. CONCLUSIONS: Exoscope-assisted surgery for spinal DAVFs is comparable in safety and effectiveness to traditional microscopic surgery. With practice, experienced neurosurgeons can adapt to using the exoscope without major additional risks to the patient.

Long-term treatment outcomes and natural course of low-grade intracranial dural arteriovenous fistulas.

OBJECTIVE: In contrast to high-grade dural arteriovenous fistula (dAVF), low-grade dAVF is mainly associated with tinnitus and carries a low risk of morbidity and mortality. It remains unclear whether the benefits of active interventions outweigh the associated risk of complications in low-grade dAVF. METHODS: The authors conducted a retrospective single-center study that included all consecutive patients diagnosed with an intracranial low-grade dAVF (Cognard type I and IIa) during 2012-2022 with DSA. The authors analyzed symptom relief, symptomatic angiographic cure, treatment-related complications, risk for intracerebral hemorrhage (ICH), and mortality. All patients were followed up until the end of 2022. RESULTS: A total of 81 patients were diagnosed with a low-grade dAVF. Of these, 48 patients (59%) underwent treatment (all primary endovascular treatments), and 33 patients (41%) did not undergo treatment. Nine patients (19%) underwent retreatments. Angiographic follow-up was performed after median (IQR) 7.7 (6.1-24.1) months by means of DSA (mean 15.0, median 6.4 months, range 4.5-83.4 months) or MRA (mean 29.3, median 24.7 months, range 5.9-62.1 months). Symptom control was achieved in 98% of treated patients after final treatment. On final angiographic follow-up, 73% of patients had a completely occluded dAVF. There were 2 treatment-related complications resulting in 1 transient (2%) and 1 permanent (2%) neurological complication. One patient showed recurrence and progression of a completely occluded low-grade dAVF to an asymptomatic high-grade dAVF. No cases of ICH- or dAVF-related mortality were found in either treated patients (median [IQR] follow-up 5.1 [2.0-6.8] years) or untreated patients (median [IQR] follow-up 5.7 [3.2-9.0] years). CONCLUSIONS: Treatment of low-grade dAVF provides a high rate of symptom relief with small risks for complications with neurological sequela. The risks of ICH and mortality in patients with untreated low-grade dAVF are minimal. Symptoms may not reveal high-grade recurrence, and radiological follow-up may be warranted in selected patients with treated low-grade dAVF. An optimal radiographic follow-up regimen should be developed by a future prospective multicenter registry.

Even short-term training improves the skills of novice exoscope users: a prospective laboratory experiment.

BACKGROUND: The surgical 3D exoscopes have recently been introduced as an alternative to the surgical microscopes in microneurosurgery. Since the exoscope availability is still limited, it is relevant to know whether even a short-term exoscope training develops the skills needed for performing exoscope-assisted surgeries. METHODS: Ten participants (six consultants, four residents) performed two laboratory bypass test tasks with a 3D exoscope (Aesculap Aeos®). Six training sessions (6 h) were performed in between (interval of 2-5 weeks) on artificial models. The participants were divided into two groups: test group (n = 6) trained with the exoscope and control group (n = 4) with a surgical microscope. The test task was an artificial end-to-side microsurgical anastomosis model, using 12 interrupted 9-0 sutures and recorded on video. We compared the individual as well as group performance among the test subjects based on suturing time, anastomosis quality, and manual dexterity. RESULTS: Altogether, 20 bypass tasks were performed (baseline n = 10, follow-up n = 10). The median duration decreased by 28 min and 44% in the exoscope training group. The decrease was steeper (29 min, 45%) among the participants with less than 6 years of microneurosurgery experience compared to the more experienced participants (13 min, 24%). After training, the participants with at least 1-year experience of using the exoscope did not improve their task duration. The training with the exoscope led to a greater time reduction than the training with the microscope (44% vs 17%). CONCLUSIONS: Even short-term training with the exoscope led to marked improvements in exoscope-assisted bypass suturing among novice microneurosurgeons. For the more experienced participants, a plateau in the initial learning curve was reached quickly. A much longer-term effort might be needed to witness further improvement in this user group.

Flow diversion of ruptured intracranial aneurysms: a single-center study with a standardized antithrombotic treatment protocol.

BACKGROUND: The use of antithrombotic medication following acute flow diversion for a ruptured intracranial aneurysm (IA) is challenging with no current guidelines. We investigated the incidence of treatment-related complications and patient outcomes after flow diversion for a ruptured IA before and after the implementation of a standardized antithrombotic medication protocol. METHODS: We conducted a single-center retrospective study including consecutive patients treated for acutely ruptured IAs with flow diversion during 2015-2023. We divided the patients into two groups: those treated before the implementation of the protocol (pre-protocol) and those treated after the implementation of the protocol (post-protocol). The primary outcomes were hemorrhagic and ischemic complications. A secondary outcome was clinical outcome using the modified Ranking Scale (mRS). RESULTS: Totally 39 patients with 40 ruptured IAs were treated with flow diversion (69% pre-protocol, 31% post-protocol). The patient mean age was 55 years, 62% were female, 63% of aneurysms were in the posterior circulation, 92% of aneurysms were non-saccular, and 44% were in poor grade on admission. Treatment differences included the use of glycoprotein IIb/IIIa inhibitors (pre-group 48% vs. post-group 100%), and the use of early dual antiplatelets (pre-group 44% vs. 92% post-group). The incidence of ischemic complications was 37% and 42% and the incidence of hemorrhagic complications was 30% and 33% in the pre- and post-groups, respectively, with no between-group differences. There were three (11%) aneurysm re-ruptures in the pre-group and none in the post-group. There were no differences in mortality or mRS 0-2 between the groups at 6 months. CONCLUSION: We found no major differences in the incidence of ischemic or hemorrhagic complications after the implementation of a standardized antithrombotic protocol for acute flow diversion for ruptured IAs. There is an urgent need for more evidence-based guidelines to optimize antithrombotic treatment after flow diversion in the setting of subarachnoid hemorrhage.

Incidence of surgically treated chronic subdural hematoma after head injury with normal initial computed tomography.

PURPOSE: The objective was to determine the incidence of surgically treated chronic subdural hematoma (cSDH) within six months after head trauma in a consecutive series of head injury patients with a normal initial computed tomography (CT). METHODS: A total of 1941 adult patients with head injuries who underwent head CT within 48 h after injury and were treated at the Tampere University Hospital's emergency department were retrospectively evaluated from medical records (median age = 59 years, IQR = 39-79 years, males = 58%, patients using antithrombotic medication = 26%). Patients with no signs of acute traumatic intracranial pathology or any type of subdural collection on initial head CT were regarded as CT negative (n = 1573, 81%). RESULTS: Two (n = 2) of the 1573 CT negative patients received surgical treatment for cSDH. Consequently, the incidence of surgically treated cSDH after a normal initial head CT during a six-month follow-up was 0.13%. Both patients sustained mild traumatic brain injuries initially. One of the two patients was on antithrombotic medication (warfarin) at the time of trauma, hence incidence of surgically treated cSDH among patients with antithrombotic medication in CT negative patients (n = 376, 23.9%) was 0.27%. Additionally, within CT negative patients, one subdural hygroma was operated shortly after trauma. CONCLUSION: The extremely low incidence of surgically treated cSDH after a normal initial head CT, even in patients on antithrombotic medication, supports the notion that routine follow-up imaging after an initial normal head CT is not indicated to exclude the development of cSDH. Additionally, our findings support the concept of cSDH not being a purely head trauma-related disease.

Digital 3D Exoscope is Safe and Effective in Surgery for Intradural Extramedullary Tumors: A Comparative Series.

BACKGROUND: Digital 3D exoscopes have been shown to be comparably safe and effective as surgical microscopes in complex microneurosurgical procedures. However, the results of exoscopic spinal tumor surgeries are scarce. The purpose of this study is to compare results of a transition from microscope to exoscope in surgeries for spinal intradural extramedullary tumors. METHODS: We included all consecutive patients with intradural extramedullary spinal tumors operated on by the senior author during January 2016 to October 2023. The 3D exoscope was used in the latter half of the series from November 2020. We evaluated pre- and postoperative clinical findings, imaging studies, intra- and postoperative events, and analyzed surgical videos from the operations retrospectively. RESULTS: We operated 35 patients (exoscope n = 19, microscope n = 16) for intradural extramedullary tumors (meningioma n = 18, schwannoma n = 12, other n = 5). Tumors in the cervical and thoracic spine were more common than in the lumbar region. The duration of surgery was slightly longer (median 220 vs. 185 minutes) in the exoscope group. However, the rate of gross total resection of the tumor was higher (81% vs. 67%) and the tumors more often located anteriorly to the spinal cord (42% vs. 13%) in the exoscope group. No major complications (i.e., permanent motor deficit or postoperative hematoma) occurred in either group. We saw postoperative gait improvement in 81% and 85% of the patients with preoperative deterioration of gait after exoscopic and microscopic surgeries, respectively. CONCLUSIONS: This study demonstrates that exoscope-assisted surgery for spinal intradural extramedullary tumors is comparable in safety and effectiveness to traditional microscopic surgery.

Temporal Changes in CSF Cell Parameters After SAH: Comparison of Ventricular and Spinal Drain Samples.

BACKGROUND: Forty percent of patients with aneurysmatic subarachnoid hemorrhage (aSAH) develop acute hydrocephalus requiring treatment with cerebrospinal fluid (CSF) drainage. CSF cell parameters are used in the diagnosis of nosocomial infections but also reflect sterile inflammation after aSAH. We aimed to study the temporal changes in CSF parameters and compare external ventricular drain (EVD)-derived and lumbar spinal drain-derived samples. METHODS: We retrospectively identified consecutive patients with aSAH treated at our neurointensive care unit between January 2014 and May 2019. We mapped the temporal changes in CSF leucocyte count, erythrocyte count, cell ratio, and cell index during the first 19 days after aSAH separately for EVD-derived and spinal drain-derived samples. We compared the sample sources using a linear mixed model, controlling for repeated sampling. RESULTS: We included 1360 CSF samples from 197 patients in the analyses. In EVD-derived samples, the CSF leucocyte count peaked at days 4-5 after aSAH, reaching a median of 225 × 106 (interquartile range [IQR] 64-618 × 106). The cell ratio and index peaked at 8-9 days (0.90% [IQR 0.35-1.98%] and 2.71 [IQR 1.25-6.73], respectively). In spinal drain-derived samples, the leucocyte count peaked at days 6-7, reaching a median of 238 × 106 (IQR 60-396 × 106). The cell ratio and index peaked at 14-15 days (4.12% [IQR 0.63-10.61%]) and 12-13 days after aSAH (8.84 [IQR 3.73-18.84]), respectively. Compared to EVD-derived samples, the leucocyte count was significantly higher in spinal drain-derived samples at days 6-17, and the cell ratio as well as the cell index was significantly higher in spinal drain-derived samples compared to EVD samples at days 10-15. CONCLUSIONS: CSF cell parameters undergo dynamic temporal changes after aSAH. CSF samples from different CSF compartments are not comparable.

Intracranial Pressure-Derived Cerebrovascular Reactivity Indices and Their Critical Thresholds: A Canadian High Resolution-Traumatic Brain Injury Validation Study.

Current neurointensive care guidelines recommend intracranial pressure (ICP) and cerebral perfusion pressure (CPP) centered management for moderate-severe traumatic brain injury (TBI) because of their demonstrated associations with patient outcome. Cerebrovascular reactivity metrics, such as the pressure reactivity index (PRx), pulse amplitude index (PAx), and RAC index, have also demonstrated significant prognostic capabilities with regard to outcome. However, critical thresholds for cerebrovascular reactivity indices have only been identified in two studies conducted at the same center. In this study, we aim to determine the critical thresholds of these metrics by leveraging a unique multi-center database. The study included a total of 354 patients from the CAnadian High-Resolution TBI (CAHR-TBI) Research Collaborative. Based on 6-month Glasgow Outcome Scores, patients were dichotomized into alive versus dead and favorable versus unfavorable. Chi-square values were then computed for incrementally increasing values of each physiological parameter of interest against outcome. The values that generated the greatest chi-squares for each parameter were considered to be the thresholds with the greatest outcome discriminatory capacity. To confirm that the identified thresholds provide prognostic utility, univariate and multivariable logistical regression analyses were performed adjusting for the International Mission for Prognosis and Analysis of Clinical Trials (IMPACT) variables. Through the chi-square analysis, a lower limit CPP threshold of 60 mm Hg and ICP thresholds of 18 mm Hg and 22 mm Hg were identified for both survival and favorable outcome predictions. For the cerebrovascular reactivity metrics, different thresholds were identified for the two outcome dichotomizations. For survival prediction, thresholds of 0.35, 0.25, and 0 were identified for PRx, PAx, and RAC, respectively. For favorable outcome prediction, thresholds of 0.325, 0.20, and 0.05 were found. Univariate logistical regression analysis demonstrated that the time spent above/below thresholds were associated with outcome. Further, multivariable logistical regression analysis found that percent time above/below the identified thresholds added additional variance to the IMPACT core model for predicting both survival and favorable outcome. In this study, we were able to validate the results of the previous two works as well as to reaffirm the ICP and CPP guidelines from the Brain Trauma Foundation (BTF) and the Seattle International Severe Traumatic Brain Injury Consensus Conference (SIBICC).