Chronic subdural hematomas: a review

Combining Clinical-Radiomics Features With Machine Learning Methods for Building Models to Predict Postoperative Recurrence in Patients With Chronic Subdural Hematoma: Retrospective Cohort Study

BACKGROUND

Chronic subdural hematoma (CSDH) represents a prevalent medical condition, posing substantial challenges in postoperative management due to risks of recurrence. Such recurrences not only cause physical suffering to the patient but also add to the financial burden on the family and the health care system. Currently, prognosis determination largely depends on clinician expertise, revealing a dearth of precise prediction models in clinical settings.

OBJECTIVE

This study aims to use machine learning (ML) techniques for the construction of predictive models to assess the likelihood of CSDH recurrence after surgery, which leads to greater benefits for patients and the health care system.

METHODS

Data from 133 patients were amassed and partitioned into a training set (n=93) and a test set (n=40). Radiomics features were extracted from preoperative cranial computed tomography scans using 3D Slicer software. These features, in conjunction with clinical data and composite clinical-radiomics features, served as input variables for model development. Four distinct ML algorithms were used to build predictive models, and their performance was rigorously evaluated via accuracy, area under the curve (AUC), and recall metrics. The optimal model was identified, followed by recursive feature elimination for feature selection, leading to enhanced predictive efficacy. External validation was conducted using data sets from additional health care facilities.

RESULTS

Following rigorous experimental analysis, the support vector machine model, predicated on clinical-radiomics features, emerged as the most efficacious for predicting postoperative recurrence in patients with CSDH. Subsequent to feature selection, key variables exerting significant impact on the model were incorporated as the input set, thereby augmenting its predictive accuracy. The model demonstrated robust performance, with metrics including accuracy of 92.72%, AUC of 91.34%, and recall of 93.16%. External validation further substantiated its effectiveness, yielding an accuracy of 90.32%, AUC of 91.32%, and recall of 88.37%, affirming its clinical applicability.

CONCLUSIONS

This study substantiates the feasibility and clinical relevance of an ML-based predictive model, using clinical-radiomics features, for relatively accurate prognostication of postoperative recurrence in patients with CSDH. If the model is integrated into clinical practice, it will be of great significance in enhancing the quality and efficiency of clinical decision-making processes, which can improve the accuracy of diagnosis and treatment, reduce unnecessary tests and surgeries, and reduce the waste of medical resources.

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.

Spontaneous Intracranial Hypotension and Subdural Hematomas Treatment Management Using MMA Embolization and Target Blood Patch: A Case Report

We report a patient suffering from spontaneous intracranial hypotension (SIH) who, following a non-selective lumbar blood patch, returned to his healthcare provider with severe symptoms of neurological deficits. It was subsequently discovered that the aforementioned deficits were due to a bilateral subdural hematoma, and an emergency surgical drainage of the hematoma has been performed. However, the hematoma reformed and potential cerebrospinal fluid leakage was consequently investigated through myelography. Following the diagnostic finding of a venous diverticulum, a selective blood patch was executed in the affected area, and in order to stabilize the hematoma, an embolization of the middle meningeal arteries was performed. The combination of such operations allowed for the resorption of the hematoma and the improvement of neurological symptoms.

Efficacy and safety of steroids for chronic subdural hematoma: A systematic review and meta-analysis

Background

Chronic subdural hematoma (CSDH) is a condition characterized by the accumulation of fluid, blood, and blood breakdown products between the brain's arachnoid and dura mater coverings. While steroids have been explored as a potential treatment option, their efficacy and safety remain uncertain. This meta-analysis and systematic review aimed to assess the impact of steroids on CSDH management, including mortality, recurrence, complications, and functional outcomes.

Methods

We conducted a comprehensive literature search in major electronic databases up to June 2023, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Cochrane Handbook for Systematic Reviews and Interventions. Inclusion criteria encompassed adult patients with CSDH, the use of steroids as monotherapy or adjuvant therapy, and clearly defined outcomes. Randomized controlled trials and cohort studies meeting these criteria were included in the study.

Results

The initial search yielded 4315 articles, with 12 studies meeting the inclusion criteria. Our findings indicate a non-significant trend toward reduced mortality with steroids in combination with standard care (Odds ratios [OR] = 0.66, 95% confidence interval [CI] 0.20-2.18). However, substantial heterogeneity was observed (I2 = 70%). Sensitivity analysis, excluding influential studies, suggested a potential increased mortality risk associated with steroids (OR = 1.47, 95% CI 0.87-2.48). Steroids showed a possible benefit in reducing the recurrence of CSDH (OR = 0.58, 95% CI 0.20-1.67), but with significant heterogeneity (I2 = 89%). No clear advantage of steroids was observed in terms of functional outcomes at three months (modified Rankin scale scores). Furthermore, steroids were associated with a significantly higher incidence of adverse effects and complications (OR = 2.17, 95% CI 1.48-3.17).

Conclusion

Steroids may have a potential role in reducing CSDH recurrence but do not appear to confer significant advantages in terms of mortality or functional outcomes. However, their use is associated with a higher risk of adverse effects and complications. Given the limitations of existing studies, further research is needed to refine the role of steroids in CSDH management, considering patient-specific factors and treatment protocols.

Factors for predicting recurrence after burr hole drainage for chronic subdural hematoma: a retrospective study

Chronic subdural hematoma (SDH) is a common disease in the neurosurgical field, and hematoma drainage through burr hole trephination has been widely considered the optimal treatment for SDH. Despite numerous investigations aimed at predicting recurrence rates and associated factors, studies have demonstrated inconsistent results. In this study, we aimed to comprehensively determine the predictive factors of chronic SDH recurrence in surgically treated patients. We retrospectively evaluated 578 consecutive patients who underwent single burr hole surgery for chronic SDH at our institute between January 2008 and December 2021. Various clinical and radiological factors in patients with and without recurrence were compared using univariate and multivariate logistic regression analyses. A total of 438 patients (531 hemispheres) were analyzed. Fifty-four (10.17%) of the 531 hemispheres had recurrence of chronic SDH within 6 months. Male sex (adjusted odds ratio (aOR) = 3.48; 95% confidence interval (CI), 1.42-8.49), bilateral hematomas (aOR = 2.14; 95% CI, 1.05-4.35), laminar hematoma type (aOR = 2.87; 95% CI, 1.23-6.71), > 30-cm3 volume of postoperative residual hematoma (aOR = 2.99; 95% CI, 1.01-8.83), and preoperative blood glucose level of ≥ 150 mg/dL (aOR = 2.11; 95% CI, 1.10-4.05) were identified as independent factors associated with recurrence in multivariate logistic regression analysis. The present study revealed that male patients and those who had bilateral hematomas, laminar hematoma type, a large volume of hematoma after surgery, and a high preoperative blood glucose level had a higher probability of experiencing recurrent chronic SDH. We recommend close monitoring of patients 6 months postoperatively to detect subsequent chronic SDH recurrence.

Immunometabolic Profiling of Chronic Subdural Hematoma through Untargeted Mass Spectrometry Analysis: Preliminary Findings of a Novel Approach

Objective: Metabolomics has growing importance in the research of inflammatory processes. Chronic subdural hematoma (cSDH) is considered to be, at least in part, of inflammatory nature, but no metabolic analyses yet exist. Therefore, a mass spectrometry untargeted metabolic analysis was performed on hematoma samples from patients with cSDH. Methods: A prospective analytical cross-sectional study on the efficacy of subperiosteal drains in cSDH was performed. Newly diagnosed patients had the option of granting permission for the collection of a hematoma sample upon its removal. The samples were analyzed using liquid chromatography-mass spectrometry to obtain different types of metabolites from diverse biochemical classes. The statistical analysis included data cleaning, imputation, and log transformation, followed by PCA, PLS-DA, HCA, and ANOVA. The postoperative course of the disease was followed for 3 months. The metabolite concentrations in the hematoma fluid were compared based on whether a recurrence of the disease was recorded within this time frame. Results: Fifty-nine samples from patients who were operated on because of a cSDH were gathered. Among those, 8 samples were eliminated because of missing metabolites, and only 51 samples were analyzed further. Additionally, 39 samples were from patients who showed no recurrence over the course of a 3-month follow-up, and 12 samples were from a group with later recurrence. We recorded a noticeable drop (35%) in the concentration of acylcarnitines in the "recurrence group", where 10 of the 22 tested metabolites showed a significant reduction (p < 0.05). Furthermore, a noticeable reduction in different Acyl-CoA-dehydrogenases was detected (VLCAD-deficiency p < 0.05, MCAD-deficiency p = 0.07). No further changes were detected between both populations. Conclusions: The current study presents a new approach to the research of cSDH. The measurements presented us with new data, which, to date, are without any reference values. Therefore, it is difficult to interpret the information, and our conclusions should be considered to be only speculative. The results do, however, point in the direction of impaired fatty acid oxidation for cases with later recurrence. As fatty acid oxidation plays an important role in inflammatory energy metabolism, the results suggest that inflammatory processes could be aggravated in cases with recurrence. Because our findings are neither proven through further analyses nor offer an obvious therapy option, their implications would not change everyday practice in the management of cSDH. They do, however, present a further possibility of research that might, in the future, be relevant to the therapy.

Development of machine learning models for predicting unfavorable functional outcomes from preoperative data in patients with chronic subdural hematomas

Chronic subdural hematoma (CSDH) often causes neurological deterioration and is treated with hematoma evacuation. This study aimed to assess the feasibility of various machine learning models to preoperatively predict the functional outcome of patients with CSDH. Data were retrospectively collected from patients who underwent CSDH surgery at two institutions: one for internal validation and the other for external validation. The poor functional outcome was defined as a modified Rankin scale score of 3-6 upon hospital discharge. The unfavorable outcome was predicted using four machine learning algorithms on an internal held-out cohort (n = 188): logistic regression, support vector machine (SVM), random forest, and light gradient boosting machine. The prediction performance of these models was also validated in an external cohort (n = 99). The area under the curve of the receiver operating characteristic curve (ROC-AUC) of each machine learning-based model was found to be high in both validations (internal: 0.906-0.925, external: 0.833-0.860). In external validation, the SVM model demonstrated the highest ROC-AUC of 0.860 and accuracy of 0.919. This study revealed the potential of machine learning algorithms in predicting unfavorable outcomes at discharge among patients with CSDH undergoing burr hole surgery.

Middle Meningeal Artery Embolization for the Management of Chronic Subdural Hematoma

Introduction Chronic subdural hematoma (cSDH) results from neovascularization of the subdural capsular membrane and embolization of the Middle Meningeal Artery (MMA) helps inhibit the same and prevent recurrence. Materials and methods We retrospectively reviewed the endovascular management for chronic SDH in 29 patients between 2018 to 2022. The parameters analyzed were clinical history, radiologic imaging findings, procedure details, and angiographic and clinical outcomes. Results Twenty-nine MMA embolization procedures were done. Follow-up MRI or CT done in 28 subjects, showed complete resolution in 25 patients and a significant reduction in bilateral SDH in three patients. One patient died due to renal failure and aspiration pneumonia-related complications. Ninety days mRS (modified Rankin scale) was 0 in 25 patients (86%), one in two patients, and two in one patient. Conclusions  MMA embolization for chronic SDH is a feasible, safe, and effective technique in patients with chronic and recurrent SDH.

Assessing the accuracy of the International Classification of Disease (ICD) framework in the identification of patients with chronic subdural haematoma from hospital records

BACKGROUND

Chronic subdural hematoma (CSDH) is one of the commonest neurosurgical pathologies with an increasing incidence. Observational studies of routine care have demonstrated high perioperative morbidity and approximately 10% mortality at one year. The development, implementation, and evaluation of a potential care framework relies on an accurate and reproducible method of case identification and case ascertainment. With this manuscript, we report on the accuracy of diagnostic ICD codes for identifying patients with CSDH from retrospective electronic data and explore whether basic demographic data could improve the identification of CSDH.

METHODS

Data were collected retrospectively from the hospital administrative system between 2014 and 2018 of all patients coded with either S065 or I620. Analysis of the ICD codes in identifying patients with CSDH diagnosis was calculated using the caretR package in RStudioR,.and stepwise logistic regression analysis was performed to evaluate the best predictive model for CSDH.

RESULTS

A total of 1861 patients were identified. Of these, 189 (10.2%) had a diagnosis of non-traumatic SDH (I620) and 1672 (89.8%) traumatic subdural haematomas (S065). Variables that identified CSDH as a diagnosis on univariate logistic regression included male sex (Odds Ratios (OR) - 1.606 (1.197-2.161), elderly age (OR) - 1.023 (1.015-1.032) per year for age (p < 0.001) and shorter length of hospital stay. Using stepwise regression against AIC the best model to predict CSDH included male sex, older age, and shorter LOS. The calculated sensitivity for identifying CSDH with the model is 88.4% with a specificity of 84.5% and PPV of 87.9%.

CONCLUSION

CSDH is a common neurosurgical pathology with increasing incidence and ongoing unmet clinical need. We demonstrate that case ascertainment for research purposes can be improved with the incorporation of additional demographic data but at the expense of significant case exclusion.

Outcome of Chronic Subdural Hematoma Intervention in Patients on Long-Term Antiplatelet Therapy-A Propensity Score Matched Analysis

BACKGROUND

Patients presenting with chronic subdural hematomas (cSDHs) and on antiplatelet medications for various medical conditions often complicate surgical decision making.

OBJECTIVE

To evaluate risks of preprocedural and postprocedural antiplatelet use in patients with cSDHs.

METHODS

Patients with cSDH who were treated between January 2006 and February 2022 at a single institution with surgical intervention were identified. A propensity score matching analysis was then performed analyzing length of hospitalization, periprocedural complications, reintervention rate, rebleeding risk, and reintervention rates.

RESULTS

Preintervention, 178 patients were on long-term antiplatelet medication and 298 were not on any form of antiplatelet. Sixty matched pairs were included in the propensity score analysis. Postintervention, 88 patients were resumed on antiplatelet medication, whereas 388 patients did not have resumption of antiplatelets. Fifty-five pairs of matched patients were included in the postintervention propensity score analysis. No significant differences were found in length of hospitalization (7.8 ± 4.2 vs 6.8 ± 5.4, P = .25), procedural complications (3.3% vs 6.7%, P = .68), or reintervention during the same admission (3.3% vs 5%, P = 1). No significant differences were seen in recurrence rate (9.1% vs 10.9%, P = 1) or reintervention rate after discharge (7.3% vs 9.1%, P = 1) in the postintervention group.

CONCLUSION

Preintervention antiplatelet medications before cSDH treatment do not affect length of hospitalization, periprocedural complications, or reintervention. Resumption of antiplatelet medication after cSDH procedures does not increase the rebleeding risk or reintervention rate.

Comparison of different surgical techniques for chronic subdural hematoma: a network meta-analysis

Background

Chronic subdural hematoma (CSDH) is a neurosurgical condition with high prevalence. Many surgical approaches are recommended for treating CSDH, but there needs to be a consensus on the optimal technique. This network meta-analysis (NMA) compared the efficacy and safety of different surgical treatments for CSDH.

Methods

Electronic databases, including PubMed, Embase, and the Cochrane Library, were searched for relevant studies up to February 2023. An NMA was performed to compare the outcomes of patients with CSDH treated by single-hole or double-hole craniotomy (SBHC and DBHC, respectively), twist-drill craniotomy (TDC), mini-craniotomy, and craniotomy. The NMA protocol was registered at INPLASY (registration no. 202320114).

Results

The NMA included 38 studies with 7,337 patients. For efficacy outcomes, DBHC showed the highest surface under the cumulative ranking area (SUCRA) values for recurrence (96.3%) and reoperation (87.4%) rates. DBHC differed significantly from mini-craniotomy in recurrence rate (odds ratio [OR] = 0.58, 95% confidence interval [CI]: 0.35, 0.97) and from SBHC (OR = 0.48, 95% CI: 0.25, 0.91) and TDC (OR = 0.40, 95% CI: 0.20, 0.82) in reoperation rate. For operative time, TDC was superior to SBHC (mean difference [MD] = -2.32, 95% CI: -3.78 to -0.86), DBHC (MD = -3.61, 95% CI: -5.55, -1.67), and mini-craniotomy (MD = -3.39, 95% CI: -5.70, -1.08). Patients treated by TDC had a shorter hospital stay than those treated by SBHC (MD = -0.82, 95% CI: -1.51, -0.12). For safety outcomes, there were no significant differences between groups in mortality and complication rates; however, mini-craniotomy (79.8%) and TDC (78.1%) had the highest SUCRAs.

Conclusion

DBHC may be the most effective surgical treatment for CSDH based on the low recurrence and reoperation rates, although all examined techniques were relatively safe.

Systematic review registration

https://inplasy.com/inplasy-2023-2-0114/.

Recurrent Subdural Hematoma: An Institutional Experience

Background Chronic subdural hematoma (CSDH) is a common neurosurgical problem, which offers a good outcome following surgery. In many cases, burr hole irrigation and drainage under local anesthesia can provide satisfactory results. However, recurrence can be a cause for concern for both the surgeon and the patient. While recurrence is not a frequent phenomenon, studies have reported rates of up to 31.6%. Aims and objectives In this study, our objective is to examine a comprehensive range of potential risk factors and provide valuable insights into identifying patients at a higher risk of recurrence to aid in surgical decision-making. Methodology This study employed a prospective and retrospective design, conducted between 2017 and 2021, at Sri Ramachandra Institute of Higher Education and Research. The study received ethical approval from the Institutional Ethics Committee. The research aimed to assess patients who underwent surgery for CSDH, with a particular focus on those who experienced recurrence. Results The average age of patients with recurrence was 71.5 years compared to 65.2 years in the no-recurrence group, but this difference did not show a significant statistical correlation. A significant male predominance was observed, with 27 men and four women affected (out of a total of 147 men and 73 women in the study), resulting in a statistically significant p-value of 0.01. On multivariate analysis, heterogenous subtypes were a significant predictor of recurrence (OR: 8.88, 95% CI: 6.96-16.54, p = 0.01). The mean midline shift in those with recurrence was 11.4 mm compared to 7.09 mm in those without recurrence. This was a statistically significant correlation with a p-value of 0.02. Regarding those with recurrence, 24 patients underwent evacuation using two burr holes, with one placed in the frontal region and another in the parietal region. All of these patients had a subdural drain placed, which was removed on postoperative day 2. The remaining eight patients underwent a mini-craniotomy for evacuation. We had four cases of refractory CSDH, all of whom underwent the second evacuation using burr holes. Three of them underwent evacuation via craniotomy, while the family of the fourth patient did not give consent for the procedure. Conclusion Patient-related factors such as gender, bilateral presentation, and the presence of hypertension and radiological factors such as the presence of heterogenous subtype and a significant midline shift are clues toward a higher chance of recurrence.

Incidence of Chronic Subdural Hematoma after Mild Head Trauma in Elderly Patients with or without Pre-traumatic Conditioning of Anti-thrombotic Drugs

Anti-thrombotic drugs may increase the risk for chronic subdural hematoma (CSDH). However, whether to continue or discontinue/counteract these drugs has not been investigated in patients with mild head trauma. CSDH incidence after mild head trauma, as well as the risk for CSDH in patients with anti-thrombotic drugs, were investigated in this study. The study included 765 consecutive elderly (>65 y.o.) patients with mild head trauma and an initial Glasgow Coma Scale (GCS) score of 14 or 15. All patients received initial CT within 24 hours after trauma and were re-examined 30 days after trauma to detect CSDH formation, repeating for every 30 days to examine symptomatic CSDH progression. Patients were divided into two groups, with anti-thrombotic drugs (n = 195) or without them (n = 263), to investigate the influence of pre-traumatic conditioning with anti-thrombotic drugs on CSDH. The whole sample was 458 out of 765 cases. The incidence of CSDH formation was 91 out of 458 cases (19.9%) after mild head trauma, with no significant difference between with and without anti-thrombotic drugs. CSDH progressed as symptomatic in 21 out of 458 cases (4.6%), with no significant difference between with and without anti-thrombotic drugs. Pre-traumatic conditioning with anti-thrombotic drugs and its continuation after trauma did not affect the incidence of formation or symptomatic progression of CSDH. This finding suggests that discontinuing and/or counteracting anti-thrombotic drugs may be unnecessary in patients with mild head trauma.

Change in Hematoma Size after Dexamethasone Therapy in Chronic Subdural Hematoma Subtypes: A Prospective Study in Symptomatic Patients

The main treatment strategy for chronic subdural hematoma is surgical intervention. When a conservative pharmacological approach is considered in symptomatic patients, mainly dexamethasone therapy is applied. Recent trials revealed dexamethasone therapy to be an ineffective treatment in symptomatic patients with chronic subdural hematoma. Whether the efficacy of dexamethasone therapy differs in radiological hematoma subtypes is unknown. The aim of this substudy was to identify which hematoma subtype might be favorable for dexamethasone therapy. As part of a randomized controlled trial, symptomatic chronic subdural hematoma patients received 19-days dexamethasone therapy. The primary outcome measure was the change in hematoma size as measured on follow-up computed tomography (CT) after 2 weeks of dexamethasone in six hematoma (architectural and density) subtypes: homogeneous total, laminar, separated and trabecular architecture types, and hematoma without hyperdense components (homogeneous hypodense, isodense) and with hyperdense components (homogeneous hyperdense, mixed density). We analyzed hematoma thickness, midline shift, and volume using multi-variable linear regression adjusting for age, sex and baseline value of the specific radiological parameter. From September 2016 until February 2021, 85 patients were included with a total of 114 chronic subdural hematoma. The mean age was 76 years and 25% were women. Larger decrease in hematoma thickness and midline shift was revealed in hematoma without hyperdense components compared with hematoma with hyperdense components (adjusted [adj.] b -2.2 mm, 95% confidence interval [CI] -4.1 to -0.3 and adj. b -1.3 mm, 95% CI -2.7 to 0.0 respectively). Additional surgery was performed in 57% of patients with the highest observed rate (81%) in separated hematoma. Largest hematoma reduction and better clinical improvement was observed in chronic subdural hematoma without hyperdense components after dexamethasone therapy. Evaluation of these parameters can be part of an individualized treatment strategy.

Surgical treatment and outcome of chronic subdural hematoma: a comparative study between Ethiopia and Norway

BACKGROUND

Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions. Here, we studied differences in demographics, treatment, and outcome for CSDH patients in low-income (Ethiopia) and high-income (Norway) countries and assessed potential outcome determinants.

METHODS

We included patients from Addis Ababa University Hospitals (AAUH) and Haukeland University Hospital (HUH) who had surgery for CSDH (2013-2017). Patients were included prospectively in Ethiopia and retrospectively in Norway.

RESULTS

We enrolled 314 patients from AAUH and 284 patients from HUH, with a median age of 60 and 75 years, respectively. Trauma history was more common in AAUH (72%) than in HUH patients (64.1%). More patients at HUH (45.1%) used anticoagulants/antiplatelets than at AAUH (3.2%). Comorbidities were more frequent in HUH (77.5%) than in AAUH patients (30.3%). Burr hole craniostomy under local anesthesia and postoperative drainage was the standard treatment in both countries. Postoperative CT scanning was more common at HUH (99.3%) than at AAUH (5.2%). Reoperations were more frequent at HUH (10.9%) than at AAUH (6.1%), and in both countries, mostly due to hematoma recurrence. Medical complications were more common at HUH (6.7%) than at AAUH (1.3%). The 1-year mortality rate at HUH was 7% and at AAUH 3.5%. At the end of follow-up (> 3 years), the Glasgow Outcome Scale Extended (GOSE) score was 8 in 82.9% of AAUH and 46.8% of HUH patients.

CONCLUSION

The surgical treatment was similar at AAUH and HUH. The poorer outcome in Norway could largely be explained by age, comorbidity, medication, and complication rates.

Traumatic subdural hygroma and chronic subdural hematoma: A systematic review and meta-analysis

Recently, a relationship between traumatic subdural hygroma (SDG) and chronic subdural hematoma (CSDH) has been proposed. However, the role of traumatic SDG in development of CSDH has not been well characterized. This systematic review aimed to estimate the rate of evolution of traumatic SDG to CSDH, and to identify risk factors associated with traumatic SDG evolution to CSDH. We searched MEDLINE, EMBASE, and Cochrane Library databases from inception to May 26, 2021, using the combination of the terms "subdural hygroma" and "chronic subdural hematoma." Using a random-effects model, we calculated a pooled estimate of rate of evolution of traumatic SDG to CSDH. In addition, we conducted a systematic review of studies of risk factors for traumatic SDG evolution to CSDH. Nineteen studies with 1,335 patients met the inclusion criteria for meta-analysis. The pooled estimate of evolution rate was 25.0 % (95 % CI, 19.3 %-30.7 %; I² = 85.6 %), with significant heterogeneity among studies (P < 0.01). Age ≥ 60 years was associated independently with traumatic SDG evolution to CSDH, after adjustment for study design using multivariate meta-regression. Risk factors associated with evolution of traumatic SDG to CSDH were radiological characteristics such as thicker SDG and higher SDG CT value. The rate of traumatic SDGs evolution to CSDH is approximately 25 %. Patients aged 60 or older with traumatic SDGs are at increased risk of CSDH development. Thicker SDG and higher SDG CT value, are commonly reported risk factors for traumatic SDG evolution to CSDH. However, higher quality studies are needed.

A bibliometric analysis of chronic subdural hematoma since the twenty-first century

BACKGROUND

Chronic subdural hematoma (CSDH) is a common disease that forms between the dura and arachnoid membranes of the brain. With the development of medications and surgery, significant progress has been made in the diagnosis and treatment of CSDH. However, there is no comprehensive analysis available on CSDH-related studies published in the literature. This study aimed to collect and analyze CSDH-related studies published since the twenty-first century using bibliometric analysis and to summarize the current status of research in this field for the sake of providing systematic data for further study of CSDH.

METHODS

CSDH-related studies were searched in the Web of Science Core Collection (WoSCC) database using the Medical Subject Heading (MeSH) term 'chronic subdural hematoma'. Data analysis and visualization were performed by R and CiteSpace software.

RESULTS

This study retrieved 1424 CSDH-related articles published since the beginning of the twenty-first century. There was a general increase in both the number of published articles and the mean number of citations. The authors, institutions and journals that contributed the most to the field of CSDH were Jianning Zhang, Tianjin Medical University, and world neurosurgery, respectively. The reference co-citation network identified 13 clusters with significant modularity Q scores and silhouette scores (Q = 0.7124, S = 0.8536). The major research categories were (1) evolution of the therapeutic method and (2) the etiology and pathology of CSDH. Keyword analysis revealed that 'middle meningeal artery embolization' was the latest burst keyword.

CONCLUSIONS

This study identified the most influential countries, authors, institutions and journals contributing to CSDH research and discussed the hotspots and the latest subjects of CSDH research.

Anti-Inflammatory Drug Therapy in Chronic Subdural Hematoma: A Systematic Review and Meta-Analysis of Prospective Randomized, Double-Blind and Placebo-Controlled Trials

Althoughanti-inflammatory drug therapy has been identified as potentially beneficial for patients suffering from chronic subdural hematoma (cSDH), contemporary literature presents contradictory results. In this meta-analysis, we aimed to investigate the impact of anti-inflammatory drug therapy on mortality and outcome. We searched for eligible randomized, placebo-controlled prospective trials (RTCs) on PubMed, Embase and Medline until July 2022. From 97 initially identified articles, five RTCs met the criteria and were included in our meta-analysis. Our results illustrate significantly lower rates of recurrent cSDH (OR: 0.35; 95% CI: 0.21-0.58, p = 0.0001) in patients undergoing anti-inflammatory therapy. In the subgroup of patients undergoing primary conservative treatment, anti-inflammatory therapy was associated with lower rates of "switch to surgery" cases (OR: 0.30; 95% CI: 0.14-0.63, p = 0.002). Despite these findings, anti-inflammatory drugs seemed to be associated with higher mortality rates in patients undergoing surgery (OR: 1.76; 95% CI: 1.03-3.01, p = 0.04), although in the case of primary conservative treatment, no effect on mortality has been observed (OR: 2.45; 95% CI: 0.35-17.15, p = 0.37). Further multicentric prospective randomized trials are needed to evaluate anti-inflammatory drugs as potentially suitable therapy for asymptomatic patients with cSDH to avoid the necessity of surgical hematoma evacuation on what are predominantly elderly, vulnerable, patients.

Surgical Management of the Armored Brain: Case Report of the Treatment of a Chronic Calcified Subdural Hematoma

Calcified chronic subdural hematomas (CCSDHs) are rare entities, whose yearly incidence ranges from 1.72 to 20.6 per every 100 thousand persons. Several different approaches to their management are reported in the literature, ranging from conservative treatment to craniotomy with full removal of the neomembranes. Currently, there are no guidelines or consensus that establish the best technique. We herein report a case of symptomatic CCSDH initially drained through a burr-hole craniotomy, with no resolution of the symptoms. Later, our patient underwent a craniotomy and partial membranectomy, which resulted in full symptomatic recovery.

Investigation of Neutrophil Extracellular Traps as Potential Mediators in the Pathogenesis of Non-Acute Subdural Hematomas: A Pilot Study

Non-acute subdural hematomas (NASHs) are a cause of significant morbidity and mortality, particularly with recurrences. Although recurrence is believed to involve a disordered neuroinflammatory cascade involving vascular endothelial growth factor (VEGF), this pathway has yet to be completely elucidated. Neutrophil extracellular traps (NETs) are key factors that promote inflammation/apoptosis and can be induced by VEGF. We investigated whether NETs are present in NASH membranes, quantified NET concentrations, and examined whether NET and VEGF levels are correlated in NASHs. Samples from patients undergoing NASH evacuation were collected during surgery and postoperatively at 24 and 48 h. Fluid samples and NASH membranes were analyzed for levels of VEGF, NETs, and platelet activation. NASH samples contained numerous neutrophils positive for NET formation. Myeloperoxidase-DNA complexes (a marker of NETs) remained elevated 48 h postoperatively (1.06 ± 0.22 day 0, 0.72 ± 0.23 day 1, and 0.83 ± 0.33 day 2). VEGF was also elevated in NASHs (7.08 ± 0.98 ng/mL day 0, 3.40 ± 0.68 ng/mL day 1, and 6.05 ± 1.8 ng/mL day 2). VEGF levels were significantly correlated with myeloperoxidase-DNA levels. These results show that NETs are increasing in NASH, a finding that was previously unknown. The strong correlation between NET and VEGF levels indicates that VEGF may be an important mediator of NET-related inflammation in NASH.

Chronic Subdural Hematoma-Evolution of Etiology and Surgical Treatment

In this paper, I review the historical changes in the etiological concepts and surgical treatments for chronic subdural hematoma (CSDH) across the world and in Japan. I also examine future problems associated with its surgical procedures and medical costs. CSDH was first reported by Wepfer in 1657 as "delayed apoplexy." In 1857, Virchow described the famous concept of so-called "pachymeningitis hemorrhagica interna." He considered that the etiology of CSDH involved inflammation. In 1914, Trotter described the origin of CSDH as traumatic. Currently, CSDH is considered to arise with a first leak of blood from dural border cells after mild trauma. Inflammatory cells are then drawn to the border cell layer. At this point, new membranes form from activated inflammation; then, the hematoma enlarges, promoted by angiogenic factors and new capillaries. In 1883, Hulke reported successful trepanning of a patient with CSDH. Burr holes and craniotomy for removal of the hematoma were subsequently reported, and new methods were developed over the course of several decades around the world. In Japan, after the first report by Nakada in 1938, many Japanese pioneering figures of neurological surgery have studied CSDH. After Mandai reported the middle meningeal artery embolization in 2000, this method is now considered useful as an initial or second treatment for CSDH. However, the age of patients is increasing, so more minimally invasive surgeries and useful pharmacotherapies are needed. We must also consider the costs for treating CSDH, because of the increasing numbers of surgical cases.

Conservative Treatment of Chronic Subdural Hematoma with Gorei-san

Most asymptomatic patients with chronic subdural hematoma (CSDH) are followed conservatively but can require surgical treatment if the hematoma expands. We conducted a retrospective evaluation of the effect of Gorei-san on CSDH. This study included patients treated between April 2013 and March 2015. In total, 289 patients were diagnosed with CSDH and 110 patients received conservative management. Finally, 39 patients who met the requirements were registered. We retrospectively examined the age, gender, medical history, hematoma thickness, clarity of sulci below hematomas, and midline shift of the patients. The primary outcome was the median surgery-free interval, and the secondary results were the rate of CSDH shrinkage and surgery avoidance. A comparison of patient characteristics between the Gorei-san (G) and non-Gorei-san (NG) groups found no significant differences in the percentage of men, average ages, past history, thickness of CSDH (15.0 ± 3.1 mm vs. 15.3 ± 2.6 mm, p = 0.801), or midline shift (2.0 ± 2.7 mm vs. 4.0 ± 5.0 mm, p = 0.230). The median surgery-free interval was significantly different between the G and NG groups [n. r. vs. 41 days (95% CI: 5-79), log-rank p = 0.047]. The CSDH avoidance rate was not significantly different between the two groups (70.0% vs. 34.4%, p = 0.071). Additionally, the CSDH shrinkage rate was significantly different between the two groups (60.0% vs. 10.3%, p = 0.004). This retrospective study demonstrated that CSDH treatment with Gorei-san reduces hematoma significantly more than treatment that does not include Gorei-san.

Peripheral blood eosinophil and classification of residual hematoma help predict the recurrence of chronic subdural hematoma after initial surgery

Chronic subdural hematoma (CSDH) is a common type of intracranial hemorrhage in neurosurgical practice, whose incidence has increased markedly in recent years. However, CSDH still troubles clinicians with a high postoperative recurrence rate. The presence of eosinophils has been confirmed in some CSDH surgical specimens. Furthermore, postoperative residual hematoma has not been classified, and its association with the recurrence of CSDH remains unknown. The present study aimed to test the hypothesis that the peripheral blood eosinophils and the classification of postoperative residual hematoma are significant for the prediction of CSDH recurrence after burr-hole surgery. A retrospective review of 258 CSDH patients who received burr-hole surgery was performed. A complete blood picture with differential count was taken before surgery. Clinical, laboratory, and radiographic factors predicting CSDH recurrence were identified in univariable and multivariable analyses. Univariable analysis showed that the percentage of eosinophils, peripheral blood eosinophil count <0.15 × 10⁹/L, gradation and separated types, postoperative volume of the residual cavity ≥70 ml, residual air volume ≥28 ml, residual hematoma volume ≥55 ml, residual hematoma width ≥1.4 cm, postoperative midline shift ≥5.6 mm, postoperative brain re-expansion rate <41%, postoperative low-density type, and postoperative high-density type correlated with the recurrence of CSDH. Multivariable analysis, however, showed that peripheral blood eosinophil count <0.15 × 10⁹/L, gradation and separated types, preoperative midline shift ≥9.5 mm, postoperative brain re-expansion rate <41%, postoperative low-density type, and postoperative high-density type are independent predictors for the recurrence of CSDH. We expect that peripheral blood eosinophils and the classification of postoperative residual hematoma may facilitate our understanding of the recurrence of CSDH after initial surgery.

Dexamethasone reduces vascular endothelial growth factor in comparison to placebo in post-operative chronic subdural hematoma samples: A target for future drug therapy?

Background

Chronic subdural hematoma (CSDH) is a collection of blood and fluid that arises on the brain surface due to a combination of trauma and/or inflammation. The mainstay of treatment is surgical drainage, but CSDH can recur. Dexamethasone has been shown to reduce CSDH recurrence, but its mechanism of action has not been fully elucidated. Understanding the inflammatory mediators driving CSDH formation and recurrence and how dexamethasone alters this can help develop new therapeutic strategies.

Methods

A subgroup of adult patients recruited to the Dex-CSDH trial, randomized to dexamethasone or placebo, who had surgery for their CSDH, were included. CSDH fluid and peripheral blood were collected intraoperatively, from post-operative drains and operated recurrences. Samples were analyzed using a 12-plex panel of inflammatory mediators. Clinical patient data were also reviewed.

Results

A total of 52 patients, with a mean age of 76 years, were included. Five recurrent CSDHs occurred. Vascular endothelial growth factor (VEGF) had the highest concentration across all CSDHs, and only matrix metalloproteinase (MMP)-9 had lower concentrations in CSDH compared to plasma but was increased in recurrent CSDHs. The interleukin (IL)-10 concentration was significantly lower in primary CSDHs that recurred. Most inflammatory mediators increased post-operatively, and dexamethasone significantly reduced the post-operative peak in VEGF on day 2, compared to placebo.

Conclusion

It is evident that VEGF plays a critical role in the inflammatory response in CSDH. The post-operative reduction with dexamethasone could signal the mechanism by which it reduces recurrence. Novel therapies with a better side-effect profile than dexamethasone should be targeted at VEGF or potential alternatives such as IL-10 supplementation.

Puerto Rico Recurrence Scale: Predicting chronic subdural hematoma recurrence risk after initial surgical drainage

Background:

Chronic subdural hematoma (CSDH) commonly affects older individuals and is associated with a relatively high rate of recurrence after surgery. Many studies have created grading systems to identify patients at high risk of CSDH recurrence after the initial surgery. However, no system has been adopted widely. The authors present the first CSDH grading system created from a population-based single-center data set.

Methods:

A single-center Puerto Rican population-based retrospective analysis was performed on consecutive patients treated for a CSDH at a designated institution from July 1, 2017 to December 31, 2019. Univariate and multivariate analyses were used to create a CSDH recurrence grading scale. Retrospective validation was conducted on this sample population.

Results:

The study included 428 patients. Preoperative midline shift, postoperative midline shift, and size of postoperative subdural space differed between the recurrence and nonrecurrence groups (P = 0.03, 0.002, and 0.002, respectively). A multivariate analysis was used to create a 10-point grading scale comprising four independent variables. Recurrence rates progressively increased from the low-risk (0–3 points) to high-risk (8–10 points) groups (2.9% vs. 20.3%; P < 0.001).

Conclusion:

A 10-point grading scale for CSDH recurrence was developed with four components: preoperative midline shift (≤1 and >1 cm), laterality (bilateral, unilateral-right, and unilateral-left), size of postoperative subdural space (≤1.6 and >1.6 cm), and pneumocephalus (present or absent). Patients who scored higher on the scale had a higher risk of recurrence. This CSDH grading scale has implications for Puerto Rico and the general population as the elderly population increases worldwide.

Schulz J, Wiesmann M, Altiok E, Höllig A. Chronic Subdural Hematoma

BACKGROUND

Chronic subdural hematoma (cSDH) is typically a disease that affects the elderly. Neurosurgical evacuation is generally indicated for hematomas that are wider than the thickness of the skull. The available guidelines do not address the common clinical issue of the proper management of antithrombotic drugs that the patient has been taking up to the time of diagnosis of the cSDH. Whether antithrombotic treatment should be stopped or continued depends on whether the concern about spontaneous or postoperative intracranial bleeding, and a presumably higher rate of progression or recurrence, with continued medication outweighs the concern about a possibly higher rate of thrombotic complications if it is stopped.

METHODS

In this article, we review publications from January 2015 to October 2020 addressing the issue of the management of antithrombotics in patients with cSDH that were retrieved by a selective search in the Pubmed and EMBASE databases, and we present the findings of a cohort study of 395 patients who underwent surgery for cSDH consecutively between October 2014 and December 2019.

RESULTS

The findings published in the literature are difficult to summarize concisely because of the heterogeneity of study designs. Among the seven studies in which a group of patients on antithrombotics was compared with a control group, four revealed significant differences with respect to the risk of thromboembolic complications depending on previous antithrombotic use and the duration of discontinuation, while three others did not. In our own cohort, discontinuation of antithrombotics (including both plasmatic and antiplatelet drugs) was associated with thrombotic complications in 9.1% of patients.

CONCLUSION

These findings imply that the management of antithrombotics should be dealt with critically on an individual basis. In patients with cSDH who are at elevated risk, an early restart of antithrombotic treatment or even an operation under continued antithrombotic therapy should be considered.

Chronic subdural hemorrhage predisposes to development of cerebral venous thrombosis and associated retinal hemorrhages and subdural rebleeds in infants

For infants presenting with subdural hemorrhage, retinal hemorrhage, and neurological decline the "consensus" opinion is that this constellation represents child abuse and that cerebral venous sinus thrombosis and cortical vein thrombosis is a false mimic. This article contends that this conclusion is false for a subset of infants with no evidence of spinal, external head, or body injury and is the result of a poor radiologic evidence base and misinterpreted data. Underdiagnosis of thrombosis is the result of rapid clot dissolution and radiologic under recognition. A pre-existing/chronic subdural hemorrhage predisposes to development of venous sinus thrombosis/cortical vein thrombosis, triggered by minor trauma or an acute life-threatening event such as dysphagic choking, variably leading to retinal and subdural hemorrhages and neurologic decline. These conclusions are based on analysis of the neuroradiologic imaging findings in 11 infants, all featuring undiagnosed cortical vein or venous sinus thrombosis. Subtle neuroradiologic signs of and the mechanisms of thrombosis are discussed. Subarachnoid hemorrhage from leaking thrombosed cortical veins may be confused with acute subdural hemorrhage and probably contributes to the development of retinal hemorrhage ala Terson's syndrome. Chronic subdural hemorrhage rebleeding from minor trauma likely occurs more readily than bleeding from traumatic bridging vein rupture. Radiologists must meet the challenge of stringent evaluation of neuro imaging studies; any infant with a pre-existing subdural hemorrhage presenting with neurologic decline must be assumed to have venous sinus or cortical vein thrombosis until proven otherwise.

Bilateral subdural hematoma caused by spontaneous intracranial hypotension originating from a discogenic microspur successfully treated with duraplasty: A case report

Introduction

Discogenic microspurs are calcified outgrowths from the intervertebral disc which can perforate the dura, causing a leak of cerebrospinal fluid (CSF). Spontaneous leaks of the CSF present a recognized cause of spontaneous intracranial hypotension (SIH). Moreover, subdural hematomas (SDH) are a potentially severe complication of SIH.

Research question

We present a case of a bilateral subdural hematoma without orthostatic headaches caused by a discogenic microspur protruding from the T1-2 intervertebral disc. The microspur is conjectured to be the culprit of the leak by ventrally perforating the dura and catalyzing the causal chain leading to the formation of the subdural hemorrhage.

Material and methods

A 79-year woman noticed a progressive gait disturbance accompanied by a decline of short-term memory over several months without experiencing orthostatic headaches. Magnetic resonance imaging (MRI) showed extensive bilateral subdural fronto-parietal hematoma, signs of CSF hypotension (dilated venous compartments), and computed tomography (CT) myelography revealed a CSF leak originating at the T1-2 level.

Results

The leakage site was treated with microsurgical duraplasty leading to a regression of the symptoms and complete resolution of the subdural hematomas within five postoperative months.

Discussion and conclusion

Discogenic microspurs can perforate the dura causing a CSF leak, leading to spontaneous intracranial hypotension, finally resulting in a bilateral subdural hematoma. This constellation of symptoms does not necessarily induce orthostatic headaches and can be treated with microsurgical duraplasty.

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Discogenic microspur perforating the dura and inducing a liquor leak.

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Discogenic microspur leading to spontaneous intracranial hypotension.

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Discogenic microspur leading to bilateral subdural hematoma.

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Liquor leak treated by microsurgical duraplasty.

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Bilateral subdural hematoma retraction after microsurgical duraplasty.

A Radiological Assessment of Chronic Subdural Hematomas

Chronic subdural hematoma (CSDH), which generally occurs in elderly patients, is a frequently diagnosed condition in neurosurgical departments. Computed tomography (CT) and magnetic resonance imaging (MRI) are the most preferred diagnostic modalities for CSDH assessment. With early diagnosis and adequate management, CSDH may show favorable prognosis in majority of the patients; however, recurrence after surgery can occur in a significant number of patients. The recently increasing number of CSDH studies could reveal the prognostic factors affecting CSDH recurrence. Particularly, radiological characteristics regarding the internal architecture of CSDH are considered closely associated with recurrence in surgically treated CSDH patients. In this literature review, we evaluated the various diagnostic modalities of CSDH and its radiological characteristics on CT and MRI. Furthermore, we summarized the prognostic factors of recurrence for the hematoma type based on the radiological findings.

The effect of antithrombotic therapy on the recurrence and outcome of chronic subdural hematoma after burr-hole craniostomy in a population-based cohort

PURPOSE

To study the effect of antithrombotic therapy (ATT) on the outcome of operatively treated chronic subdural hematomas (CSDH).

METHODS

A retrospective population-based cohort study from Eastern Finland including all adult patients who underwent a burr-hole craniostomy (BHC) for CSDH during 2016 and 2017. The follow-up time for recurrence was 6 months and for mortality 3 years.

RESULTS

A total of 301 CSDH patients were included in the study. ATT (antithrombotic therapy; antiplatelet or anticoagulant medication) was used by 164 patients (54.5%) at the time of diagnosis. The hematoma was bilateral in 102 patients (33.9%). Forty-seven patients (15.8%) encountered hematoma recurrence. Bilateral CSDHs required reoperations more often than unilateral hematomas (12.6% vs. 22.0%; p = 0.036) regardless of the primary operation (uni- or bilateral). A bivariate logistic regression analysis showed that bilateral hematoma (OR 1.918; 95% CI 1.013-3.630; p = 0.045) and male gender (OR 2.363; 95% CI 1.089-5.128; p = 0.030) independently predicted hematoma recurrence. The overall three-year mortality was 27.9%. The use of ATT was not associated with CSDH recurrence, and the length of the temporary postoperative ATT discontinuation did not correlate with the rate of thromboembolic events.

CONCLUSIONS

ATT did not affect CSDH recurrence in our study population, and the duration of the temporary postoperative ATT discontinuation was not associated with the rate of thromboembolic complications. Male gender and bilateral hematomas were more frequently associated with recurrences.

Cerebrospinal fluid leak as a driving factor in chronic subdural hematoma formation: A histological study

Background:

Chronic subdural hematoma (CSDH) represents the most common neurosurgical disease. Given the demographic shift toward an aging population, the overall incidence of this condition is increasing. Nevertheless, clarity in the pathophysiological process is yet to be made. Several etiological mechanisms have been proposed to initiate and consequently promote fluid collection in the subdural space. Traumatic injury of the bridging veins has long been considered the primum movens of the pathology but increasing evidence shows that trauma is not the only factor involved. Along with recent advances we sought to understand the role of the cerebrospinal fluid (CSF) in the buildup of the intense inflammatory reaction that characterizes CSDH.

Methods:

In the present study, we examined histological features of reactive membranes secondary to extracranial CSF leakage with CSDH-related membranes. Similarity and differences between the specimens were examined by means of light microscopy.

Results:

Histological similarities were consistently found between CSDH membranes and reactive membranes secondary to CSF leakage in the extracranial space. Activated histiocytes were highlighted in all specimens along with an intense inflammatory reaction.

Conclusion:

CSDH is most likely the result of a complex interaction among different pathophysiological events resulting from both traumatic and inflammatory etiologies. In the present work, we highlight how CSF leakage could be an early factor that leads to a cascade of events that culminates in CSDH formation.

Paradigms in chronic subdural hematoma pathophysiology: Current treatments and new directions

ABSTRACT

Chronic subdural hematomas (CSDHs) are an increasingly common pathology encountered in a neurosurgical trauma practice. Although the operative and nonoperative management of CSDH has been studied extensively, the recurrence rate of CSDH remains high, with no significant decrease in recent years. We undertook a detailed assessment of the known pathophysiological mechanisms by which CSDHs recur to improve our ability to treat patients with this disease successfully. In this review of the literature from the PubMed and Scopus databases, we used the search terms "(pathophysiology) AND chronic subdural hematoma [tiab]" to identify pertinent reviews and articles in English. The results demonstrated a complex inflammatory response to subdural blood, which begins with the formation of a collagen neomembrane around the clot itself. Proinflammatory mediators, such as vascular endothelial growth factor, interleukin-6, interleukin-8, tissue necrosis factor α, matrix metalloproteinases, and basic fibroblast growth factor, then contribute to chronic microbleeding by promoting the formation of fragile, leaky blood vessels, and widening of gap junctions of existing vessels. It is evident that the lack of improvement in recurrence rate is due to pathological factors that are not entirely alleviated by simple subdural evacuation. Targeted approaches, such as middle meningeal artery embolization and anti-inflammatory therapies, have become increasingly common and require further prospective analysis to aid in the determination of their efficacy.

Middle Meningeal Artery Embolization and the Treatment of a Chronic Subdural Hematoma

Chronic subdural hematoma (cSDH) is a common pathology that typically affects the elderly. It is believed to occur due to injury to the dural border cells, which creates an inflammation/proliferation reaction. Ineffective repair leads to the formation of a new external layer of cells and fragile capillaries, which damage easily and can worsen the condition. Conventionally, asymptomatic cSDH is managed by observation, and symptomatic cases are treated by surgical evacuation. Unfortunately, recurrence rates of the SDH following surgical evacuation can be high. One treatment option for SDH involves embolization of the middle meningeal artery (MMA). The MMA provides blood supply to the dura mater and feeds the membrane capillaries covering the SDH. MMA embolization blocks the blood flow to this system and can promote hematoma resolution. In this paper, we review the existing literature on MMA embolization and discuss the underlying pathophysiology of cSDH.

Recommencement of anticoagulation/antiplatelet therapy following non-operative management of a Chronic Subdural Hematoma - Is there an optimal time frame?

Background

There is no consensus among clinicians regarding recommencement of antithrombotic agents following conservative management of a Chronic Subdural Hematoma (cSDH). Thus, the primary objective of this study was to determine the most commonly recommended interval and whether the data reveal a general consensus that should be adopted.

Methods

A retrospective analysis of Salford Royal Foundation Trust's Neurosurgical referral database for patients referred with a cSDH between March 2017 and March 2020 was carried out. Patients were sorted by whether they were on blood-thinning medications.

Results

Over the 3-year period, there were a total of 1220 referral and 1099 patients. 502 (41.14%) of these referrals and 479 (43.59%) patients were on one more blood thinning agent. Of these patients 221 (46.13%) conservative management, there was a clear male predominance (M: F ≈ 2.5:1) in this cohort. 2 weeks was the most commonly advised time-frame (n = 76, 36.36%) to withhold. Of the 234 referrals, there were 13 (5.88%) re-referrals in total. Crucially, there was no significant difference in reaccumulation rates between patients asked to withhold their blood thinners for 2 weeks versus those asked to stop for longer than 2 weeks (P = 0.57).

Conclusion

For the majority of bleeds, there is no clear benefit from asking patients to withhold their anticoagulant/antiplatelet for longer than 2 weeks. In cases, where it is deemed appropriate to stop for longer than 2 weeks, clear instructions should be provided and documented along with reasons behind the decision.

Postoperative recurrence of chronic subdural hematoma is more frequent in patients with blood type A

OBJECTIVE

Because of an aging society, the incidence of chronic subdural hematoma (CSDH) is increasing. This lesion is treated with simple burr hole irrigation, but one of the major issues is that CSDH frequently recurs. ABO blood type may be associated with a bleeding tendency and inflammation. However, its association with the recurrence of CSDH remains unknown. Therefore, the authors of the present study aimed to retrospectively investigate the association between ABO blood type and CSDH recurrence.

METHODS

The authors retrospectively analyzed symptomatic CSDHs in 425 cerebral hemispheres of 376 patients who had undergone surgical treatment with irrigation of the hematoma via burr holes at their institution from January 2011 to September 2019. Among these were 366 CSDHs in 320 patients whose ABO blood type had been determined and who were included in this study.

RESULTS

In the study, 307 patients with CSDHs in 350 hemispheres were followed up postoperatively until the disappearance of the CDSH or for at least 3 months. Recurrence of CSDH was observed in 37 patients (10.6%) after surgical treatment. Blood type A was found to be significantly associated with CSDH recurrence compared to non-A blood types: 24 of 153 CDSHs (15.7%) versus 13 of 197 CDSHs (6.6%) (p = 0.008). In the multivariable regression analysis, blood type A, in addition to thrombocytopenia, was a significant independent predictor of the recurrence of CSDH.

CONCLUSIONS

The study results showed that blood type A is an independent risk factor for the postoperative recurrence of CSDH and that careful follow-up in these patients may be needed.

Modified Burr-Hole Craniostomy for the Treatment of Chronic Subdural Hematoma in Adults

BACKGROUND

Burr-hole craniostomy (BHC) is considered to be the most effective method for the treatment of chronic subdural hematoma (CSDH), and middle meningeal artery embolization is a new therapy used in clinical practice in recent years to treat CSDH. However, the optimal therapeutic effect of these 2 procedures is still controversial. This study prospectively designed a modified burr-hole craniostomy (mBHC) with drainage to treat CSDH.

METHODS

A total of 101 patients diagnosed with CSDH from January 2019 to April 2020 were prospectively included in this study. They were divided into BHC and mBHC groups. Among them, 40 selected CSDH patients received mBHC treatment. For comparison, 61 CSDH patients who received BHC treatment were used as the control group. Primary outcomes were hematoma recurrence and postoperative complications. Secondary outcomes included midline recovery, hematoma clearance, operation time, and hospital stay. The Chi-square test was used to compare the 6-month follow-up results between the 2 groups.

RESULTS

Among patients treated with mBHC, 39 patients had a good prognosis, and one 87-year-old patient with bilateral hematoma died of postoperative heart failure. Of the patients treated with BHC, 52 patients had good prognoses, and one 53-year-old patient with unilateral hematoma died of postoperative acute intracranial bleeding. During the 6-month follow-up period, no relapse occurred in the patients treated with mBHC, whereas 8 (13%) of the patients treated with BHC relapsed. There was a significant difference in the recurrence rate between the 2 groups (P < 0.05). In addition, midline recovery, hematoma clearance rate, operation time, and complications were found to be significantly different statistically (P < 0.05), and other characteristics of operation and outcome were not significantly different (P > 0.05) between the 2 groups.

CONCLUSIONS

Modified burr-hole craniostomy has a positive therapeutic effect on patients with CSDH and is more effective than conventional BHC therapy.

Rare but Fatal Subdural Hematoma Following Spinal Anesthesia: A Case Report of Unrecognized Untreated Postdural Puncture Headache in a Low-Resource Country Setting

Dural puncture following neuraxial anesthesia can cause persistent cerebrospinal fluid leakage. A 35-year-old, 39-week gestation healthy parturient underwent cesarean delivery under spinal anesthesia. Spinal anesthesia was performed using a 25-gauge Quincke needle. Despite the occurrence of postoperative positional headache and neck pain, she was discharged home. Two weeks following discharge, she developed seizures and deteriorating level of consciousness. Brain computerized tomography scan revealed massive left subdural hematoma. She died 3 days later. We discuss awareness of neuraxial complication among maternity staff, effective follow-up, and available management strategy in low-resource settings. Persistent headache following neuraxial anesthesia should be investigated.

Atorvastatin Plus Low-Dose Dexamethasone May Be Effective for Leukemia-Related Chronic Subdural Hematoma but Not for Leukemia Encephalopathy: A Report of Three Cases

We are not aware of any reports regarding conservative treatment for leukemia-related chronic subdural hematoma (CSDH). We report our experience with 3 men who were admitted with subdural masses and abnormal leukocyte counts. In two patients, leukemia and CSDH were confirmed on the basis of medical records, mild head trauma, and neuroimaging features. Both patients experienced reduced CSDH and neurological symptoms after receiving atorvastatin (20 mg/day) plus low-dose dexamethasone. However, this combined conservative treatment was ineffective in the third patient, who was diagnosed as having leukemia and showed an increased hematoma volume after two weeks of therapy. Magnetic resonance imaging findings suggested dural metastasis, which prompted a switch from statin-based conservative treatment to chemotherapy. Complete remission of the leukemia and resolution of the subdural mass were observed after chemotherapy, which supported a diagnosis of leukemia encephalopathy. The 5-month follow-ups did not reveal CSDH relapse in all 3 cases. Thus, atorvastatin-based conservative treatment may be effective for leukemia-related CSDH but not for leukemia encephalopathy.

The Crucial Role of Eosinophils in the Life Cycle, Radiographical Architecture, and Risk of Recurrence of Chronic Subdural Hematomas

Chronic subdural hematomas (CSDHs) are a common neurological condition, whose incidence is expected to increase with an aging population. Although surgical evacuation is the mainstay of treatment, it results in a recurrence requiring reoperation (RrR) in 3-30% of cases. Recurrence is thought to be driven by a combination of inflammatory and angiogenic processes occurring within the CSDH outer membrane. Pathological specimens of 72 primary CSDHs were examined for eosinophilic infiltrate. For each case, the pre-operative computed tomography (CT) scan was graded according to the Nakaguchi grading scheme as homogeneous, laminar, separated, or trabecular. Rate of RrR was compared based on eosinophilic infiltrate and CT grade. A dense eosinophilic infiltrate was observed in 22% of specimens. The rate of RrR among specimens with a dense eosinophilic infiltrate was 0%, whereas it was 14.3% among specimens without a dense eosinophilic infiltrate. Incidence among homogeneous, laminar, separated, and trabecular CT subtypes was 4%, 27%, 58%, and 24%, respectively. A dense eosinophilic infiltrate found within the outer membrane of a CSDH may be a marker of hematoma maturation, signaling a transition toward healing and fibrosis, and a lower risk of RrR.

Risk factors for developing subdural hematoma: a registry-based study in 1457 patients with shunted idiopathic normal pressure hydrocephalus

OBJECTIVE

Subdural hematomas and hygromas (SDHs) are common complications in idiopathic normal pressure hydrocephalus (iNPH) patients with shunts. In this registry-based study, patients with shunted iNPH were screened nationwide to identify perioperative variables that may increase the risk of SDH.

METHODS

The Swedish Hydrocephalus Quality Registry was reviewed for iNPH patients who had undergone shunt surgery in Sweden in 2004-2014. Potential risk factors for SDH were recorded preoperatively and 3 months after surgery. Drug prescriptions were identified from a national pharmacy database. Patients who developed SDHs were compared with those without SDHs.

RESULTS

The study population consisted of 1457 patients, 152 (10.4%) of whom developed an SDH. Men developed an SDH more often than women (OR 2.084, 95% CI 1.421-3.058, p < 0.001). Patients on platelet aggregation inhibitors developed an SDH more often than those who were not (OR 1.733, 95% CI 1.236-2.431, p = 0.001). At surgery, shunt opening pressures had been set 5.9 mm H2O lower in the SDH group than in the no-SDH group (109.6 ± 24.1 vs 115.5 ± 25.4 mm H2O, respectively, p = 0.009). Antisiphoning devices (ASDs) were used in 892 patients but did not prevent SDH. Mean opening pressures at surgery and the follow-up were lower with shunts with an ASD, without causing more SDHs. No other differences were seen between the groups.

CONCLUSIONS

iNPH patients in this study were diagnosed and operated on in routine practice; thus, the results represent everyday care. Male sex, antiplatelet medication, and a lower opening pressure at surgery were risk factors for SDH. Physical status and comorbidity were not. ASD did not prevent SDH, but a shunt with an ASD allowed a lower opening pressure without causing more SDHs.

Recurrent Spontaneous Bilateral Subdural Hemorrhage as a Consequence of High-Cervical Spontaneous CSF Leak—Lessons for Neurosurgeons

Spontaneous intracranial hypotension (SIH) is rare. It presents as intractable posture headache and is identified by radiological findings. It is confirmed by cerebrospinal fluid (CSF) manometry and myelography, and treatment is carried out with the help of epidural blood patch (EBP) therapy. SIH presenting with spontaneous bilateral recurrent subdural bleeds is uncommon. The cause being a high-spinal CSF leak is even more uncommon! Our patient had recurrent bilateral spontaneous chronic subdural hematomas. Myelographic examination of the spine showed a C1–C2 level leak of CSF. He was taken up for open microsurgery, and the leak was identified and closed with fibrin glue. The patient however deteriorated the next day. An EBP was applied in the lumbar region to cover the myelogram lumbar puncture site. We present a review of literature and an algorithm to detect the elusive CSF leak and effect definitive treatment, either open or EBP, to treat the source of the problem.

Herbal medicine treatment for patients with chronic subdural hematoma: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

In Asian countries, herbal medicines have been used to treat Chronic subdural hematoma (CSDH) as an adjunctive therapy. This review aims to evaluate the efficacy and safety of herbal medicine on treating CSDH and preventing recurrent CSDH.

METHODS

A literature search was conducted on PubMed, CENTRAL, Scopus, CiNii, KTKP, NDSL, OASIS, and CNKI for randomized controlled trials that evaluated the effects of herbal medicines on CSDH.

RESULTS

Seven studies (n = 646) were included. The overall methodological quality of these studies was low. In the herbal group, the meta-analysis indicated statistically significant improvements in the total effective rate and recurrence rate as compared with those in the non-herbal group. Herbal treatments were found to be relatively safe.

CONCLUSION

Herbal medicines might be efficacious in the management of CSDH and prevent its recurrence. Further rigorous studies will have to be conducted in order to make more definite conclusions.

Trephine Craniotomy versus Burr Hole Drainage for Chronic Subdural Hematoma—An Institutional Analysis of 156 Patients

Introduction Some neurosurgeons believe that doing a trephine craniotomy (TC) decreases the chance of recurrence in chronic subdural hematoma (cSDH). But this is not supported by any evidence.

Methods A retrospective analysis of patients who were operated for cSDH from 2014 to 2019 at our institute was done. Factors causing recurrence were studied.

Results A total of 156 patients were operated in the given period, among which 88 underwent TC and 68 patients underwent burr hole drainage (BHD) for evacuation of cSDH. All patients underwent two trephines or two burr holes placed according to the maximum thickness of the hematoma. Rate of recurrence in trephine group was 12.5% and in burr-hole group was 11.76% and was not statistically significant. Significant factors for recurrence included nontraumatic cSDH, anticoagulant use, presence of membranes, preoperative computed tomography (CT) showing iso- or mixed-density subdural collection and SDH volume > 60 mL. There was selection bias for the procedure. Patients with subdural membranes were preferentially taken for TC as the percentage of subdural membrane found intraoperatively was significantly greater in trephine group (51.1%) than burr-hole group (17.6%) (p value < 0.001).

When all the patients who showed membranes in CT scan were excluded, there was no statistical difference in the base line characteristics of both the groups. After excluding the patients with membranes in preoperative CT scan, there was no significant difference in recurrence rate between the two groups.

In TC group with membranes, 8 out of 45 had recurrence, whereas in burr-hole group with membranes, 8 out of 12 had recurrence. This difference was statistically significant. (p value < 0.001).

Conclusion Surgical intervention in both modalities improves patient outcome with an overall recurrence rate of 12.17%. In the absence of any identifiable membranes in preoperative CT scan, BHD is the preferred surgical intervention. We prefer TC as first choice for patients with membranes in CT scan.

Development of a delayed chronic subdural hematoma 2 months after mild traumatic brain injury with a normal initial brain computed tomography: A case report

This is a case involving the development of a delayed chronic subdural hematoma 2 months after a minor head injury with normal clinical neurological findings and brain computed tomography at initial presentation. An 84-year-old man visited the emergency department (ED) after a minor head trauma. The patient complained of dizziness and vomiting 8 hours after an injury. He was not on an antiplatelet or anticoagulant. He did not have any abnormal findings during neurological examination, and brain computed tomography did not show any intracranial pathology or skull fractures. He was admitted to the ED short-stay ward for observation and was discharged asymptomatic and stable 12 hours later. However, he presented 2 months later with dizziness and unsteady gait. He was asymptomatic within those 2 months. At the ED, his brain computed tomography showed a large right chronic subdural hematoma, compressing the right lateral and third ventricles, with a 1.2 cm midline shift, subfalcine and uncal herniations, and early hydrocephalus. An emergency burr-hole evacuation was performed. He was discharged without neurological deficit 3 days later. Emergency physicians attending to patients with normal neurologic examination and initial brain computed tomography after suffering a mild traumatic brain injury should be vigilant for a chronic subdural hematoma should the patient re-present for evaluation subsequently. The attending physician may be biased as patients could have symptoms attributed to postconcussion syndrome that may overlap with symptoms of chronic subdural hematoma. Unsteady gait and ataxia are uncommon clinical signs of postconcussion syndrome and should prompt the physician to consider a repeat brain computed tomography.

Computed tomography findings after head injury preceding chronic subdural hematoma

OBJECTIVE

Head CT is sometimes performed immediately after minor head injury; however, which cases develop into chronic subdural hematoma (CSDH) remains unclear. Here, the authors retrospectively reviewed the rare cases of CSDH treated surgically in which early head CT had been performed after the initial head trauma.

METHODS

A total of 172 patients (133 male and 39 female, median age 76 years) underwent surgery for CSDH at Gunma University Hospital between April 2010 and December 2017. Among these patients were 23 who had visited Gunma University Hospital or a nearby hospital and had undergone head CT within 7 days after the initial head trauma. Characteristics of the initial head CT were examined to identify indicators of subsequent CSDH.

RESULTS

Among the 23 CSDH cases (17 male and 6 female, median age 80 years), CT scans were obtained on the day of the initial injury (day 0) in 19 cases (25 sides) and 1-7 days after injury in 12 cases (19 sides); scans were obtained during both periods in 8 cases (12 sides), so that a total of 44 sides were examined. These CT scans were divided into two groups according to when they were obtained; cases in which scans were taken during both periods were included in both groups. Head CT performed on the day of injury showed normal findings in 5 (20%) of 25 sides, thin subdural effusion (SDE) ≤ 6 mm in 16 (64%) of 25 sides, thick SDE > 6 mm in 3 (12%) of 25 sides, and acute subdural hematoma (ASDH) in 1 (4%) of 25 sides. CT from 1-7 days after trauma showed thick SDE in 9 (47%) of 19 sides, thin SDE in 8 (42%) of 19 sides, and ASDH in 2 (11%) of 19 sides. A high-density line in the lateral direction (onion skin-like) was found between the skull and the brain in 9 (35%) of 26 sides with SDE on initial CT 0-7 days after the injury.

CONCLUSIONS

ASDH was not a common cause of CSDH. Head CT at the time of trauma that precedes CSDH often showed SDE. Such SDE that precedes CSDH was often close to the detection limit of CT immediately after the injury but became more apparent from the day after the injury.

Long-term excess mortality after chronic subdural hematoma

OBJECTIVE

To assess possible long-term excess mortality and causes of death of patients with chronic subdural hematoma (CSDH).

METHODS

A retrospective study (1990-2015) of adult patients (n = 1133, median age = 76 years old, men = 65%) with CSDH identified by ICD-codes and verified by medical records. All patients were followed until death or the end of 2017. Cumulative relative survival ratios and relative excess risks of death (RER) were estimated by comparing patients' mortality with that in the entire regional matched population. The causes of death were compared with a separate reference group formed by randomly choosing sex, age, and calendar time matched controls (4 controls per each CSDH patient).

RESULTS

The median follow-up time was 4.8 years (range = 0-27 years), and 710 (63%) of the patients died (median age at death = 84 years old). The cumulative excess mortality was 1 year = 9%, 5 years = 18%, 10 years = 27%, 15 years = 37%, and 20 years = 48%. A subgroup of CSDH patients (n = 206) with no comorbidity had no excess mortality. Excess mortality was related to poor modified Rankin score at admission (RER = 4.93) and at discharge (RER = 8.31), alcohol abuse (RER = 4.47), warfarin (RER = 2.94), age ≥ 80 years old (RER = 1.83), non-operative treatment (RER = 1.56), and non-traumatic etiology (RER = 1.69). Hematoma characteristics or recurrence were unrelated to excess mortality. Dementia was the most common cause of death among the CSDH patients (21%) and the third most common cause in the reference group (15%, p < 0.001).

CONCLUSIONS

Patients with CSDH have continuous excess mortality up to 20 years after diagnosis. Patient-related characteristics have a strong association with excess mortality, whereas specific CSDH-related findings do not. CSDH patients have an increased risk for dementia-related mortality.

Influence of Antithrombotic Medication on the Risk of Chronic Subdural Hematoma Recurrence after Burr-Hole Surgery

OBJECTIVE

Chronic subdural hematoma (CSDH) is one of the most common intracranial hemorrhages. It can be managed with a simple surgical treatment such as burr-hole trephination and drainage. However, it has a relatively high recurrence rate. The mechanisms and risk factors for the recurrence have not yet been clearly identified and studies have reported varying results.

METHODS

We analyzed 230 patients with CSDH who were treated with burr-hole trephination and drainage at our institution from March 2011 to March 2016. The patients were divided into recurrence and non-recurrence groups and the medical records of each group were used to analyze the risk factors associated with CSDH recurrence.

RESULTS

After burr-hole trephination and drainage, CSDH recurrence was observed in 49 (21.3%) of the 230 patients. In univariate analysis, none of the factors showed statistical significance with respect to CSDH recurrence. In multivariate analysis, preoperative antithrombotic medication was the only independent risk factor for CSDH recurrence (odds ratio, 2.407; 95% confidence interval, 1.047-5.531).

CONCLUSION

The present study found that preoperative antithrombotic medication was independently associated with CSDH recurrence.

The incidence of chronic subdural hematomas from 1990 to 2015 in a defined Finnish population

OBJECTIVE

The aim of this study was to determine the population-based epidemiology of chronic subdural hematoma (CSDH) over a 26-year period.

METHODS

A retrospective study was conducted of all adult patients (≥ 18 years and residents of Pirkanmaa [Finland]) with a diagnosis of CSDH between 1990 and 2015. The cases were identified using ICD codes. Detailed data collection was performed using medical records and death certificates. All patients were monitored until death or the end of year 2017. The annual number of inhabitants in the Pirkanmaa region was obtained from Statistics Finland (Helsinki, Finland).

RESULTS

A total of 1168 patients with CSDH were identified from hospital records and death certificates; patients were considered as new-incidence cases if 2 years had elapsed following primary treatment and in cases involving a new contralateral CSDH. From 1990 to 2015, the overall incidence of CSDH doubled from 8.2 to 17.6/100,000/year. Among adults younger than 70 years, the incidence remained quite stable, whereas the incidence clearly increased among the ≥ 80-year-old population, from 46.9 to 129.5/100,000/year. The median age for a CSDH diagnosis increased from 73 to 79 years during the 26-year period. Head trauma was documented in 59% of cases. A ground-level fall was related to the CSDH in 31% of patients younger than 60 years and in 54% of those 80 years or older. The proportion of alcohol-related cases decreased toward the end of the study period (1990-1995: 16% and 2011-2015: 7%), because alcohol abuse was less frequent among the growing group of elderly patients. In contrast, the percentage of patients receiving anticoagulant or antiplatelet medication almost doubled toward 2015 (1990-1995, 27%; and 2011-2015, 49%). The patients' neurological condition on admission, based on both Glasgow Coma Scale score (score < 13: 1990-1995, 18%; and 2011-2015, 7%; p < 0.001) and the modified Rankin Scale score (score 0-2: 1990-1995, 8%; and 2011-2015, 19%; p < 0.001), was better in recent years than in the early 1990s.

CONCLUSIONS

From 1990 to 2015, the incidence of CSDH has increased markedly. The incidence of CSDH among the population 80 years or older has nearly tripled since 1990. The use of anticoagulants has increased, but there has been no change regarding the ratio between a traumatic and a spontaneous CSDH etiology. As the world population becomes progressively older, the increasing incidence of CSDH will be a burden to patients and a future challenge for neurosurgical clinics.