Optimal drainage time after evacuation of chronic subdural haematoma (DRAIN TIME 2): a multicentre, randomised, multiarm and multistage non-inferiority trial in Denmark.

BACKGROUND: Postoperative drainage after surgical evacuation of chronic subdural haematoma reduces the risk of recurrence, but the optimum drainage time is uncertain. We aimed to investigate the shortest possible drainage time without increasing the haematoma recurrence rate. METHODS: We conducted a randomised, multi-arm and multistage non-inferiority trial at four neurosurgical centres in Denmark. We enrolled adult patients (aged ≥18 years) with symptomatic chronic subdural haematoma. All patients were treated according to the national standard practice with a burr hole above the maximum width of the haematoma. Patients were randomly assigned in a 1:1:1 ratio via a centralised web server to receive 6 h, 12 h, or 24 h of postoperative passive subdural drainage. Randomisation was done by an independent on-call neurosurgeon and was masked until 6 h after surgery. The primary outcome was symptomatic haematoma recurrence at 3 months after surgery; the rate of recurrence was assessed in a regression model for non-inferiority testing, with no missing data. Personnel assessing the primary outcome were masked to group allocation. Non-inferiority was assessed with a prespecified margin of 7%, in a modified intention-to-treat population-defined as patients with randomly assigned treatment excluding those withdrawing from study participation after randomisation, or experiencing acute rebleedings or accidental drain removal. This trial is registered with ISRCTN (number 15186366); the trial was stopped after the first interim analysis on the advice of an independent safety advisory committee. FINDINGS: Between March 1, 2021, and June 30, 2022, 347 patients were enrolled and 331 were followed up to 3 months, 105 were assigned to 6 h of drainage, 111 to 12 h of drainage, and 115 to 24 h of drainage. At admission, 83 (25%) participants were women and 248 (75%) were men, mean age was 75·7 years (SD 10·5), median modified Rankin Scale score was 4 (IQR 3-5), and median Glasgow Coma Scale score was 15 (IQR 14-15). At 3 months after surgery, haematoma recurrence was reported in 28 (27%) of 105 patients who were assigned to 6 h drainage (predicted haematoma recurrence rate 27·0%, 95% CI 18·5 to 35·4), 22 (20%) of 111 assigned to 12 h drainage (19·5%, 12·0 to 27·0), and 12 (10%) of 115 assigned to 24 h drainage (10·4%, 4·8 to 16·0). The risk of haematoma recurrence was increased by 16·5 percentage points (95% CI 6·5 to 26·6) in patients drained for 6 h compared with 24 h, and by 9·1 percentage points (-0·4 to 18·5) in patients drained for 12 h compared with 24 h. Therefore, non-inferiority of 6 h and 12 h of drainage to 24 h of drainage was not established. 20 patients had died by 3 months, seven in the 6 h group, eight in the 12 h group, and five in the 24 h group. The most frequent known causes of death were haematoma recurrence (three in 12 h group), comorbidity (three in 12 h group), and pneumonia (one each in 6 h and 12 h groups, two in 24 h group). The most frequent complication was postoperative infection, reported in 20 (20%) patients in the 6 h group, 25 (23%) in the 12 h group, and 19 (17%) in the 24 h group. The most common infection source was the urinary tract. INTERPRETATION: Patients surgically treated for symptomatic chronic subdural haematoma and postoperatively drained for 6 h or 12 h had higher rates of haematoma recurrence than did patients drained for 24 h. The findings from this non-inferiority trial provide evidence to support 24 h of postoperative drainage as the standard drain time when a fixed drain time approach is used. To provide solid evidence of generalisability of the results to countries other than Denmark, a multinational randomised controlled trial will be needed. FUNDING: None.

The cellular composition of chronic subdural hematoma.

INTRODUCTION: The pathophysiology of chronic subdural hematoma (CSDH) remains to be fully understood. Basic knowledge of the composition and features of cells in the CSDH fluid may contribute to the understanding of the seemingly complex processes involved in CSDH formation and recurrence. This study is the first to examine the composition of cells and of cellular features in both systemic blood and subdural fluid from CSDH patients. We hypothesized that the cellular composition and features in the hematoma fluid may be; 1) different from that in the systemic blood; 2) different between patients with and without recurrence; 3) and different between the first and second operation in patients with recurrent CSDH. METHODS: Systemic blood and subdural hematoma fluid were collected from CSDH patients with and without recurrent CSDH at the time of primary and secondary surgery. Analyses of cells and cellular features included total number of white blood cells, erythroblasts, reticulocytes, platelets, neutrophilocytes, lymphocytes, monocytes, eosinophils, basophils, reticulocytes, immature granulocytes, mean corpuscular cell volume (MCV), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, hemoglobin and hematocrit. RESULTS: Of the 85 included patients, 20 patients were operated for a recurrent CSDH within 90 days follow-up. All cells found in the systemic blood were present in the CSDH fluid, but the composition was different (p < 0.0001). MCV was higher in the hematoma fluid from the primary operation of patients later developing a recurrent CSDH compared to patients not developing recurrence (p = 0.009). Also, the percentage distribution of inflammatory cells in hematoma fluid from patients with recurrent CSDH was different between the first and second operation (p = 0.0017). CONCLUSION: This study is the first to investigate the cellular composition of CSDH fluid. Compared to systemic blood and to a reference distribution, an increased number of immune cells were present in the hematoma fluid, supporting an inflammatory component of the CSDH pathophysiology. MCV was higher in the subdural fluid at time of the first operation of CSDH patients later developing recurrence. CLINICAL TRIAL REGISTRATION: The study was approved by the Scientific Ethical Committee of the Capital Region of Denmark (Journal no. H-20051073.

Treatment of chronic subdural haematoma.

A further rise in chronic subdural haematoma (CSDH) prevalence is expected with an ageing population, and evidence-based guidelines are needed to direct treatment, while creating a platform for research. The Danish Chronic Subdural Hematoma Study (DACSUHS) has implemented the first Danish national CSDH guidelines in 2018 and have standardised CSDH management on a national level. Based on CSDH literature published between 2016 and 2022, these guidelines were updated in 2022. The updated guidelines are presented in this review.

Urokinase Plasminogen Activator Receptor: An Important Focal Player in Chronic Subdural Hematoma?

Chronic subdural hematoma (CSDH) development involves inflammatory, angiogenetic, and fibrinolytic mechanisms, several components of which are now unraveled through intensive research. The urokinase plasminogen activator receptor (uPAR) is part of the plasminogen activator system and possesses inflammatory, angiogenetic, and fibrinolytic capabilities. As a first, this study aims to identify uPAR in the hematoma fluid, hematoma membrane, dura mater, and systemic blood from patients with CSDH and, if present, to investigate if the uPAR level at the time of surgery may be a predictor for later developing recurrent CSDH. uPAR expression in the hematoma membrane and dura mater was analyzed using immunohistochemistry and presented as the H-score of the positive immunostaining. The uPAR levels in the hematoma fluid and systemic blood were determined using a multiplex antibody bead kit (Luminex). Samples were collected at the time of the first CSDH surgery, and in the case of recurrent CSDH within 90 days, the samples were again collected at reoperation. A comparison of uPAR expression between the hematoma membrane and dura mater, as well as uPAR levels in systemic blood and hematoma fluid, was performed using the Wilcoxon rank sum test. We included 112 patients, 26 of whom had recurrent CSDH. The median hematoma uPAR level was 22,125 (14,845-33,237) and significantly higher than the median systemic blood level of 789 pg/L (465-2,088) (p < 0.001). Similarly, the uPAR level of the hematoma membrane was 14.3 (7.54-44.8) and significantly higher than the dural uPAR level of 0.81 (0.3-1.98) (p < 0.001). For the first time, we identified uPAR in the subdural fluid, hematoma membrane, dura mater, and systemic blood from patients with CSDH. The high expression of uPAR in the subdural fluid and hematoma membrane indicates that the mechanisms of CSDH are predominantly in the subdural fluid collection and surrounding hematoma membrane.

Inflammatory human leucocyte antigen genotypes are not a risk factor in chronic subdural hematoma development.

BACKGROUND: Chronic subdural hematoma (CSDH) pathophysiology has undergone a paradigm shift from being regarded as solely traumatic to be driven mainly by inflammation. Human leucocyte antigen (HLA) is a gene complex involved in antigen processing and presentation to T lymphocytes, thereby mediating the adaptive immune responses. As specific HLA profiles are associated with inflammatory diseases, patients with a specific HLA profile may have a lower threshold for subdural inflammation, and therefore are predisposed for CSDH development. We hypothesized that (1) CSDH patients have a specific HLA profile compared to a Danish background population, and (2) patients with recurrent CSDH have a specific HLA profile compared to CSDH patients without recurrent CSDH. METHODS: Three specific HLA class II haplotypes known to drive inflammatory-mediated diseases were determined in 68 patients with CSDH. The distribution of these three haplotypes in our CSDH population was compared to a Danish population of blood donors using Monte Carlo Pearson's chi-square test. Furthermore, the distribution of the haplotypes was compared between CSDH patients with and without recurrent CSDH. RESULTS: We found no significant association between either of the haplotypes and the risk of CSDH, and neither of the haplotypes were associated with increased risk of CSDH recurrence. CONCLUSION: This study did not show an association between selected HLA class II haplotypes and the risk of CSDH or recurrence of CSDH compared with a healthy background population.

Early spontaneous cessation of subdural drainage after burr hole evacuation of chronic subdural hematoma and risk of recurrence.

OBJECTIVE: Subdural drainage reduces recurrence after evacuation of chronic subdural hematoma (CSDH). In the present study, the authors investigated the dynamics of drain production and potentially contributing factors for recurrence. METHOD: Patients treated with a single burr hole evacuation of CSDH between April 2019 and July 2020 were included. Patients were also participants in a randomized controlled trial. All patients included, had a passive subdural drain for exactly 24 hours. Drain production, Glasgow Coma Scale score, and degree of mobilization was recorded every hour for 24 hours. A CSDH successfully drained for 24 hours is referred to as a "case". Patients were followed for 90 days. Primary outcome was symptomatic recurrent CSDH requiring surgery. RESULTS: A total of 118 cases from 99 patients were included in the study. Of the 118 cases, 34 (29%) had spontaneous drain cessation within the first 0-8 hours after surgery (Group A), 32 (27%) within 9-16 hours (Group B), and 52 (44%) within 17-24 hours (Group C). Hours of production (P < 0.000) and total drain volume (P = 0.001) were significantly different between groups. The recurrence rate was 26.5% in group A, 15.6% in group B, and 9.6% in group C (P = 0.037). Multivariable logistic regression analysis show that cases in group C (OR: 0.13, P = 0.005) are significantly less likely to recur compared to group A. Only in 8 of the 118 cases (6.8%), the drain started draining again after an interval of three consecutive hours. CONCLUSIONS: Early spontaneous cessation of subdural drain production seems to be associated with increased risk of recurrent hematoma. Patients with early cessation of drainage did not benefit from further drain time. Observations of the present study indicate personalized drainage discontinuation strategy as a potentially alternative to a specific discontinuation time for all CSDH patients.

Subdural Levels of Interleukin 1-receptor Antagonist are Elevated in Patients with Recurrent Chronic Subdural Hematomas.

Anti-inflammatory treatment reduces the risk of recurrent chronic subdural hematoma (CSDH), but clinical implementation is improper due to side effects. Exact knowledge of subdural molecules involved in recurrent CSDH may lead to targeted medical treatment and possibly improve the prospect of a personalized approach by eliminating the broad use of anti-inflammatory drugs on the entire CSDH population. With this study, we aim to (1) describe the associations between cytokine levels at the primary surgery and the risk of subsequent recurrence and (2) describe the association between cytokines in patients with recurrent CSDH between the first and second operations. Systemic and subdural levels of pro- and anti-inflammatory cytokines were measured and compared between patients with the first-time CSDH and recurrent CSDH. Cytokine levels were analyzed using a multiplex antibody bead kit. In case of recurrent CSDH within 90 days of follow-up, the samples were re-collected and analyzed. We included 101 adult CSDH patients of which 20 had a recurrence. The levels of cytokines in the CSDH fluid from patients who were operated on for the first-time CSDH were not associated with the risk of later developing a recurrence. We found interleukin-1 receptor antagonist (IL-1ra) to be elevated in subdural fluid in patients with recurrent CSDH at the time of their second operation (p = 0.0005). This study provides knowledge on cytokine composition in the subdural fluid in patients with CSDH with and without recurrence. IL-1ra is elevated in subdural fluid in patients with recurrent CSDH at the time of the second operation, identifying a possible medical target.

The ASPECT Hydrocephalus System: a non-hierarchical descriptive system for clinical use.

In patients with hydrocephalus, prognosis and intervention are based on multiple factors. This includes, but is not limited to, time of onset, patient age, treatment history, and obstruction of cerebrospinal fluid flow. Consequently, several distinct hydrocephalus classification systems exist. The International Classification of Diseases (ICD) is universally applied, but in ICD-10 and the upcoming ICD-11, hydrocephalus diagnoses incorporate only a few factors, and the hydrocephalus diagnoses of the ICD systems are based on different clinical measures. As a consequence, multiple diagnoses can be applied to individual cases. Therefore, similar patients may be described with different diagnoses, while clinically different patients may be diagnosed identically. This causes unnecessary dispersion in hydrocephalus diagnostics, rendering the ICD classification of little use for research and clinical decision-making. This paper critically reviews the ICD systems for scientific and functional limitations in the classification of hydrocephalus and presents a new descriptive system. We propose describing hydrocephalus by a system consisting of six clinical key factors of hydrocephalus: A (anatomy); S (symptomatology); P (previous interventions); E (etiology); C (complications); T (time-onset and current age). The "ASPECT Hydrocephalus System" is a systematic, nuanced, and applicable description of patients with hydrocephalus, with a potential to resolve the major issues of previous classifications, thus providing new opportunities for standardized treatment and research.

The Danish Chronic Subdural Hematoma Study-Risk Factors for Second Recurrence.

BACKGROUND: Treatment of multiple recurrent chronic subdural hematomas (CSDH) is challenging. Identification of specific risk factors for multiple recurrences may allow a higher degree of personalized treatment, including closer postoperative follow-up, detailed prognostication, and a more aggressive initial surgical strategy, such as craniotomy, adjuvant embolization of the middle meningeal artery, or adjuvant medical treatment, such as steroids. The aim of this study was to identify pretreatment risk factors for a second recurrence of CSDH (re-re-CSDH) and risk factors for developing re-re-CSDH once operated for the first recurrence. METHODS: Clinical and demographic data on all Danish patients admitted to a neurosurgical department with CSDH between 2010 and 2012 were retrospectively recorded. Data were retrieved before the evacuation of a primary CSDH, a first recurrent CSDH (re-CSDH), and a re-re-CSDH. We compared patients undergoing first, second, and third CSDH evacuation to identify risk factors for re-CSDH and re-re-CSDH. RESULTS: The cohort comprised 1052 patients, with 172 patients with re-CSDH and 29 patients with re-re-CSDH. Risk factors for re-re-CSDH included radiological subtype, midline shift, and hematoma volume, while postoperative drainage lowered the risk of re-re-CSDH. These risk factors were not specific for re-re-CSDH. CONCLUSIONS: We found similar independent risk factors for re-CSDH and re-re-CSDH, and for re-re-CSDH once treated for re-CSDH. Hence, it was not possible to identify specific risk factors for patients at risk of re-re-CSDH at the time of the primary diagnosis.

Patient costs and patient flow after implementation of S100B in Scandinavian head trauma guidelines.

INTRODUCTION: The serum biomarker S100B has been implemented in the Scandinavian Neurotrauma Committee (SNC) 2013 Head Injury Guidelines for patients classified with mild head injury (MHI). Patients with a serum S100B level less-than 0.10 µg/l sampled within six hours after trauma can be discharged without further observation or investigation. The aim of this study was to examine the influence of S100B implementation on patient costs and patient flow in an emergency department. METHODS: In this retrospective study, we included MHI patients (≥ 18 years) admitted to Rigshospitalet, Copenhagen, Denmark, between 1 February 2013 and 31 January 2014. Medical records were examined for the time of trauma, time of S100B sampling, serum S100B level, the severity of the head injury, clinical symptoms, radiological examinations, hospitalisation, discharge, surgical intervention, readmission and mortality. RESULTS: Among 2,033 patients screened for potential study candidates, 227 patients met the inclusion criteria and were enrolled in the study. Among these patients, 119 (52%) were not treated according to SNC 2013 Head Injury Guidelines, leaving 108 (48%) with full guideline adherence. Compared with MHI management without S100B, implementation of S100B produced an additional cost of €1.26 per patient. Overall, the addition of S100B did not affect the waiting time for examination with S100B sampling or CT. CONCLUSION: The use of S100B in the SNC 2013 Head Injury Guidelines did not reduce patient costs, nor did it cause substantial additional patient costs or delayed patient flow. FUNDING: none. TRIAL REGISTRATION: The Danish Data Protection Agency (journal number 2012-58-0004 and I-suite number RH-2017-164).

Postoperative drainage for 6, 12, or 24 h after burr-hole evacuation of chronic subdural hematoma in symptomatic patients (DRAIN-TIME 2): study protocol for a nationwide randomized controlled trial.

BACKGROUND: Chronic subdural hematoma (CSDH) is a common acute or subacute neurosurgical condition, typically treated by burr-hole evacuation and drainage. Recurrent CSDH occurs in 5-20% of cases and requires reoperation in symptomatic patients, sometimes repeatedly. Postoperative subdural drainage of maximal 48 h is effective in reducing recurrent hematomas. However, the shortest possible drainage time without increasing the recurrence rate is unknown. METHODS: DRAIN-TIME 2 is a Danish multi-center, randomized controlled trial of postoperative drainage time including all four neurosurgical departments in Denmark. Both incapacitated and mentally competent patients are enrolled. Patients older than 18 years, free of other intracranial pathologies or history of previous brain surgery, are recruited at the time of admission or no later than 6 h after surgery. Each patient is randomized to either 6, 12, or 24 h of passive subdural drainage following single burr-hole evacuation of a CSDH. Mentally competent patients are asked to complete the SF-36 questionnaire. The primary endpoint is CSDH recurrence rate at 90 days. Secondary outcome measures include SF-36 at 90 days, length of hospital stay, drain-related complications, and complications related to immobilization and mortality. DISCUSSION: This multi-center trial will provide evidence regarding the shortest possible drainage time without increasing the recurrence rate. The potential impact of this study is significant as we believe that a shorter drainage period may be associated with fewer drain-related complications, fewer complications related to immobilization, and shorter hospital stays-thus reducing the overall health service burden from this condition. The expected benefits for patients' lives and health costs will increase as the CSDH patient population grows. TRIAL REGISTRATION: ISRCTN Registry ISRCTN15186366 . Registered in December 2020 and updated in October 2021. This protocol was developed in accordance with the SPIRIT Checklist and by use of the structured study protocol template provided by BMC Trials.

National randomized clinical trial on subdural drainage time after chronic subdural hematoma evacuation.

OBJECTIVE: Placement of a subdural drain reduces recurrence and death after evacuation of chronic subdural hematoma (CSDH), but little is known about optimal drainage duration. In the present national trial, the authors investigated the effect of drainage duration on recurrence and death. METHODS: In a randomized controlled trial involving all neurosurgical departments in Denmark, patients treated with single burr hole evacuation of CSDH were randomly assigned to 24 hours or 48 hours of postoperative passive subdural drainage. Follow-up duration was 90 days, and the primary study outcome was recurrent hematoma requiring reoperation. Secondary outcome was death. In addition, complications and length of hospital stay were recorded and analyzed. RESULTS: Of the 420 included patients, 212 were assigned 24-hour drainage and 208 were assigned 48-hour drainage. The recurrence rate was 14% in the 24-hour group and 13% in the 48-hour group. Four patients died in the 24-hour group, and 8 patients died in the 48-hour group; this difference was not statistically significant. The ORs (95% CIs) for recurrence and mortality (48 hours vs 24 hours) were 0.94 (0.53-1.66) and 2.07 (0.64-7.85), respectively, in the intention-to-treat analysis. The ORs (95% CIs) for recurrence and mortality per 1-hour increase in drainage time were 1.0005 (0.9770-1.0244) and 1.0046 (0.9564-1.0554), respectively, in the as-treated sensitivity analysis that used the observed drainage times instead of the preassigned treatment groups. The rates of surgical and drain-related complications, postoperative infections, and thromboembolic events were not different between groups. The mean ± SD postoperative length of hospital stay was 7.4 ± 4.3 days for patients who received 24-hour drainage versus 8.4 ± 4.9 days for those who received 48-hour drainage (p = 0.14). The mean ± SD postoperative length of stay in the neurosurgical department was significantly shorter for the 24-hour group (2 ± 0.9 days vs 2.8 ± 1.6 days, p < 0.001). CONCLUSIONS: No significant differences in the rates of recurrent hematoma or death during 90-day follow-up were identified between the two groups that randomly received either 24- or 48-hour passive subdural drainage after burr hole evacuation of CSDH.

[Endoscopic treatment of hydrocephalus].

Endoscopic treatment of hydrocephalus provides an opportunity to reach deeply located intraventricular obstacles and, as such, it is currently the primary treatment for obstructive hydrocephalus in Denmark. This review provides an overview of conditions treatable with endoscopic neurosurgery including the surgical principles, success rate and challenges with this neurosurgical procedure.

Surgical occlusion of middle meningeal artery in treatment of chronic subdural haematoma: anatomical and technical considerations.

BACKGROUND: The primary aim of chronic subdural haematoma (CSDH) treatment is to relieve pressure to improve neurological symptoms. The secondary aim is to avoid recurrence. The blood supply from the middle meningeal artery (MMA) to the haematoma membranes has recently become a research target, to enhance our understanding of the processes leading to growth and re-growth of a CSDH. Several studies indicate that endovascular embolization of the MMA (eMMA) reduces recurrence rates, but this effect must be confirmed in a randomized controlled setting. Endovascular embolization is an advanced and costly procedure carrying a significant risk of embolism in the elderly. The aim of this study was to assess anatomical and technical aspects of surgical occlusion of the MMA (soMMA) via a single same-procedure burr hole, as an alternative to eMMA. METHOD: Technical aspects of soMMA were assessed using cadaver head dissection. MMA anatomy was examined by mapping the branching pattern and distribution of MMA in dry skulls, and CSDH position was investigated by analysis of computed tomography (CT) of CSDHs. Finally, we evaluated the possibility of CT-guided navigation to mark the branching point of the anterior MMA division on the skin. RESULTS: We established anatomical landmarks to locate the MMA and found that particularly the anterior MMA branch can be occluded through a single burr hole at the pterion during the same procedure as haematoma decompression. CT of 1454 CSDHs in 1162 patients showed that the CSDH was anteriorly located in 57.5% compared with posteriorly in only 3%. This correlated with the anterior branch of the MMA being dominant in 58% of dry skull samples examined. We further confirmed that the MMA can be localized by neuronavigation as an alternative to using anatomical landmarks and average measurements. CONCLUSION: A CSDH is mainly anteriorly located and supposedly primarily supplied by the anterior MMA branch. In a simulated setting, soMMA can be performed during the same procedure as haematoma decompression. A few reservations notwithstanding, we find that soMMA may be a viable alternative to eMMA in most CSDH cases and that soMMA should be further evaluated in a clinical setting.

Long-term telemetric intracerebral pressure monitoring as a tool in intracranial hypotension.

Intracranial hypotension (IH) remains a difficult neurosurgical diagnosis. Relying solely on the symptomatology may be misleading for both diagnosis and assessment of treatment effect as symptoms may resemble other conditions not related to IH. As such, paraclinical supplements in both diagnosis and treatment follow-up are warranted. We present a 42-year-old male with IH treated with computed tomography-guided epidural blood patch. The diagnosis and treatment assessment included continual intracerebral pressure (ICP) monitoring. We found ICP monitoring helpful in IH diagnosis and long-term assessment of treatment and propose this modality as a supplement in difficult IH cases.

The Danish Chronic Subdural Hematoma Study-comparison of hematoma age to the radiological appearance at time of diagnosis.

INTRODUCTION: Chronic subdural hematomas (CSDH) show different radiological characteristics on CT scans at the time of diagnosis. The reason for this is largely unknown. We hypothesize that the imaging characteristics reflect a time-linked pathophysiological evolution. We therefore conducted a retrospective study to examine a possible relation between the hematoma age and the radiological subtype of a CSDH. METHODS: Demographic data on patients with CSDH were retrieved from a Danish national cohort from 2010 to 2012. CT scans obtained on admission to a neurosurgical department were categorized as homogenous, separated, mixed, or membranous hematoma subtypes. The time from a known date of head injury to time of diagnostic CT was defined as hematoma age. The hematoma age was correlated to radiological hematoma subtype at the time of diagnosis by analysis of variance testing. RESULTS: In total, 543 patients were analyzed for hematoma age and classified in the following hematoma subtypes: 231 homogenous, 44 separated, 119 mixed, and 149 membranous. Patients with homogenous, separated, mixed, and membranous hematoma subtypes had a median interval of 37, 36, 40, and 60 days from head injury to diagnostic CT. We found that membranous hematoma is significantly older than other subtypes. Comparison between the other radiological subtypes showed no statistical hematoma age difference. The distribution of radiological subtypes in 590 patients without a known head injury was similar to that of patients with a known head injury. Additionally, we found that hematoma age was significantly younger for patients on antiplatelet medication. CONCLUSION: In this large national cohort, patients with membranous CSDH had a significantly longer interval between head injury and diagnosis compared to other radiological subtypes. This indicates that the radiological appearance of CSDH evolves over time, causing an alteration from different early radiological subtypes to a radiological subtype with membranes. CLINICAL TRIAL REGISTRATION NUMBER: The study was approved by the Danish Data Protection Agency (journal no.30-1145).

Drain type and technique for subdural insertion after burr hole evacuation of chronic subdural hematoma.

Strengths and limitations of subdural versus subperiosteal drain location after burr hole evacuation of chronic subdural hematoma (CSDH) are currently debated. The safety of subdural placement of a drain has been questioned in a recent study by Soleman et al. from 2019, showing a misplacement rate of 17%, and these results have been further highlighted by the same authors, with a slightly lower misplacement rate of 15.8%, in the recent paper "When the drain hits the brain." The safety of subdural drainage for CSDH depends to a high degree on type of drain and surgical technique. In this technical note, we describe drain type and technique for drain placement which is standardized in Denmark.

Embolization of the middle meningeal artery in patients with chronic subdural hematoma-a systematic review and meta-analysis.

BACKGROUND: Chronic subdural hematoma (CSDH) remains a neurosurgical condition with high recurrence rate after surgical treatment. The primary pathological mechanism is considered to be repeated microbleedings from fragile neo-vessels within the outer hematoma membrane. The neo-vessels are supplied from peripheral branches of the middle meningeal artery, and embolization of MMA (eMMA) has been performed to prevent re-bleeding episodes and thereby CSDH recurrence. OBJECTIVE: To evaluate the published evidence for the effect of eMMA in patients with recurrent CSDH. Secondarily, to investigate the effect of eMMA as an alternative to surgery for primary treatment of CSDH. METHOD: A systematic review of the literature on eMMA in patients with recurrent CSDH was conducted. PubMed, Embase, and Cochrane databases were reviewed using the search terms: Embolization, Medial Meningeal Artery, Chronic Subdural Haematoma, and Recurrence. Furthermore, the following mesh terms were used: Chronic Subdural Haematoma AND embolization AND medial meningeal artery AND recurrence. Eighteen papers were found and included. No papers were excluded. The number of patients with primary CSDH and the number of patients with recurrent CSDH treated with eMMA were listed. Furthermore, the number of recurrences in both categories was registered. RESULTS: Eighteen papers with a total of 191 included patients diagnosed with CSDH treated with eMMA for primary and recurrent CSDH were identified. Recurrence rate for patients treated with eMMA for recurrent CSDH was found to be 2.4%, 95% CI (0.5%; 11.0%), whereas the recurrence rate for patients treated with eMMA for primary CSDH was 4.1%, 95% CI (1.4%; 11.4%). CONCLUSION: eMMA is a minimally invasive procedure for treatment of CSDH. Although this study is limited by publication bias, it seems that this procedure may reduce recurrence rates compared with burr hole craniostomy for both primary and recurrent hematomas. A controlled study is warranted.