Quantitative assessment of impaired postevacuation brain re-expansion in bilateral chronic subdural haematoma: possible mechanism of the higher recurrence rate

Quantitative Assessment of Brain Expansion After Evacuation of Chronic Subdural Hematoma as a Predictor of Recurrence

BACKGROUND

A lack of brain expansion is considered a risk factor for recurrence after evacuation of a chronic subdural hematoma (CSDH). To the best of our knowledge, no studies have reported on objective measurement of brain expansion after evacuation of a CSDH.

METHODS

We performed a retrospective analysis of prospectively collected data of patients undergoing 2 burr hole evacuation of a CSDH. We measured the depth of the brain surface from the frontal burr hole dural opening after hematoma evacuation using a specially devised measuring tool. Other predictors analyzed for recurrence of hematoma were age, gender, a history of hypertension, the use of anticoagulant and/or antiplatelet agents, Glasgow coma scale score at presentation, unilateral or bilateral hematoma, computed tomography appearance, and hematoma thickness.

RESULTS

Among 88 patients who underwent hematoma evacuation, 3 (3.4%) underwent surgery for recurrence. The significant factors associated with recurrence were the presence of bilateral hematoma (P = 0.001), hematoma width >2.3 cm (P = 0.04), gradation type of hematoma on the computed tomography scan (P = 0.03), and the depth of the brain after hematoma evacuation (P = 0.02). The brain expanded less in those with recurrence, with a mean depth of the brain of 18 ± 6 mm versus 7.27 ± 7.8 mm in those without recurrence.

CONCLUSIONS

Evacuation of a CSDH through 2 burr holes, along with copious irrigation and bed rest for 3 days, resulted in a very low recurrence rate without the use of a drain. A lack of brain expansion might be a predictor of recurrence. To the best of our knowledge, this is the first study to quantitatively measure the depth of the brain at surgery in patients undergoing surgery for CSDH.

Burr hole locations are associated with recurrence in single burr hole drainage surgery for chronic subdural hematoma

Background

Various factors have been reported as risk factors for chronic subdural hematomas (CSDH) recurrence. However, few studies have quantitatively evaluated the impact of CSDH locations and burr hole positions on recurrence. This study aimed to reveal the relation between CSDH recurrence and the locations of CSDH and burr holes.

Methods

Initial single burr hole surgeries for CSDH with a drainage tube between April 2005 and October 2021 at Otemae Hospital were enrolled. Patients' medical records, CSDH volume, and CSDH computed tomography values (CTV) were evaluated. The locations of CSDH and burr holes were assessed using Montreal Neurological Institute coordinates.

Results

A total of 223 patients were enrolled, including 34 patients with bilateral CSDH, resulting in 257 surgeries investigated. The rate of CSDH recurrence requiring reoperation (RrR) was 13.5%. The RrR rate was significantly higher in patients aged ≥76 years, those with bilateral CSDH, and those with postoperative hemiplegia. In RrR, the preoperative CSDH volume was significantly larger, and CTV was significantly smaller. The locations of CSDH had no influence on recurrence. However, in RrR, the locations of burr holes were found to be more lateral and more ventral. Multivariate Cox proportional hazards regression analysis showed that bilateral CSDH, more ventral burr hole positions, and postoperative hemiplegia were risk factors for recurrence.

Conclusions

The locations of burr holes are associated with CSDH recurrence. In RrR, CSDH profiles tend to show a larger volume and reduced CTV. Hemiplegia after burr hole surgery serves as a warning sign for RrR.

Middle Meningeal Artery Embolization in the Management of Chronic Subdural Hematoma: a Comprehensive Review of Current Literature

PURPOSE OF REVIEW

Chronic subdural hematoma (cSDH) is a common intracranial hemorrhagic disorder with a high incidence rate among the elderly. While small, asymptomatic cSDH may resolve spontaneously, surgical intervention has been the treatment of choice for larger, symptomatic cases. Surgical evacuation of cSDH may be associated with high rates of recurrence, and even asymptomatic cSDH cases tend to progress. Over the last few years, middle meningeal artery (MMA) embolization has proven to be a safe non-invasive treatment of choice with favorable outcomes and a low recurrence rate. The ensuing paper discusses current treatment modalities for cSDH and reviews existing literature on the anatomy of MMA and its embolization as a treatment option for cSDH.

RECENT FINDINGS

Recent studies show that traumatic head injury leading to subdural hemorrhage can induce neovascularization that may initiate a cycle of recurrent subdural hematoma. Distal branches of MMA supply blood to the dural layers. Several studies have revealed that embolization of the MMA can stop the neovascularization process and blood flow. In addition, patients who underwent MMA embolization had a significantly quicker brain re-expansion and lower recurrence rate. Although the management of cSDH is still very much a dilemma, recent research findings bring MMA embolization to light as a promising treatment alternative and adjunctive therapy.

Subdural Lesions Linking Additional Intracranial Spaces and Chronic Subdural Hematomas: A Narrative Review with Mutual Correlation and Possible Mechanisms behind High Recurrence

The purpose of this study was two-fold. The first was to investigate the pathologic mechanisms underlying the formation of subdural fluid collection, an umbrella term referring to a condition commonly seen in the clinical setting. Accumulation of the cerebrospinal fluid (CSF) in the subdural space can be referred to in this disease category, disregarding the underlying source of the subdural fluid. However, in these two clinical situations, especially after trauma or brain surgery, fluid collection from the subarachnoid space (subdural hygroma) or from the ventricle to the subarachnoid space and infusion into the subdural space (external hydrocephalus), surgical management of critical patients may adopt the strategies of burr-hole, subduroperitoneal shunt, or ventriculoperitoneal shunt, which present distinctly different thoughts. Crucially, the former can be further transformed into chronic subdural hematoma (CSDH). The second significant theme was the pathogenesis of CSDH. Once the potential dural border cell (DBC) layer is separated such as if a wound is formed, the physiological mechanisms that seem to promote wound healing will resume in the subdural space as follows: coagulation, inflammation, fibroblast proliferation, neovascularization, and fibrinolysis. These aptly correspond to several key characteristics of CSDH formation such as the presence of both coagulation and fibrinolysis signals within the clot, neomembrane formation, angiogenesis, and recurrent bleeding, which contribute to CSDH failing to coagulate and absorb easily. Such a complexity of genesis and the possibility of arising from multiple pathological patterns provide a reasonable explanation for the high recurrence rate, even after surgery. Among the various complex and clinically challenging subdural lesions, namely, CSDH (confined to the subdural space alone), subdural hygroma (linked in two spaces), and external hydrocephalus (linked in three spaces), the ability to fully understand the different pathological mechanisms of each, differentiate them clinically, and devote more interventional strategies (including anti-inflammatory, anti-angiogenic, and anti-fibrinolysis) will be important themes in the future.

Homogeneous Chronic Subdural Hematoma with Diverse Recurrent Possibilities

Background: Evidence suggests that hyperdense (HD) chronic subdural hematomas (CSDHs) have a higher recurrence than hypodense (LD) chronic subdural hematomas. The value of mean hematoma density (MHD) has been proven to be associated with postoperative recurrence. The MHD levels in homogeneous CSDHs likely underestimate the risk of recurrence in HD homogeneous subtypes. Methods: This study investigated 42 consecutive CSDH cases between July 2010 and July 2014. The area of the hematoma was quantified to determine the MHD level using computer-based image analysis of preoperative brain CT scans. Results: In terms of the MHD distribution of the four types of CSDHs (homogeneous, laminar, separated, and trabecular), wide 95% CI (11.80-16.88) and high standard deviation (4.59) can be found in homogeneous types, reflecting a high variability in the MHD levels between cases (from low to high density). The categorization of homogeneous types into LD and HD (type five) displayed a minor standard deviation in the MHD levels for LD and HD subtypes (1.15, and 0.88, respectively). MHD values demonstrated concentrated distributions among the respective five types, compared to the four-type setting. Conclusions: In the current research, we provide a consideration that if LD and HD hematomas are separated from homogeneous CSDHs, the variability of the MHD quantification can potentially be reduced, thereby avoiding the possibility of undetected high-risk groups.

Brain re-expansion predict the recurrence of unilateral CSDH: A clinical grading system

Objective

Assessing the risk of postoperative recurrence of chronic subdural hematoma (CSDH) is a clinical focus. To screen the main factors associated with the perioperative hematoma recurrence. The brain re-expansion is the core factor of recurrence. A clinical prognostic scoring system was also proposed.

Methods

We included 295 patients with unilateral CSDH as the training group for modeling. Factors predicting postoperative recurrence requiring reoperation (RrR) were determined using univariate and multivariate regression analyses, and bivariate Pearson correlation coefficient analysis was used to exclude related factors. Receiver operating characteristic curve analysis evaluates the ability of main factors to predict RrR and determines the cut-off value of brain re-expansion rate. We developed a prognostic scoring system and conducted preliminary verification. A verification group including 119 patients with unilateral CSDH was used to verify the grading systems.

Results

The key factors for predicting unilateral CSDH recurrence were cerebral re-expansion rate (≤ 40%) at postoperative days 7–9 (OR 25.91, p < 0.001) and the preoperative CT density classification (isodense or hyperdense, or separated or laminar types) (OR 8.19, p = 0.007). Cerebral atrophy played a key role in brain re-expansion (OR 2.36, p = 0.002). The CSDH prognostic grading system ranged from 0 to 3. An increased score was associated with a more accurate progressive increase in the RrR rate (AUC = 0.856).

Conclusions

Our prognostic grading system could screen clinically high-risk RrR patients with unilateral CSDH. However, increased attention should be paid to brain re-expansion rate after surgery in patients with CSDH.

Case report: Rapid recurrence of a chronic subdural haematoma associated with prostate cancer metastasis to a haematoma capsule

Background

Chronic subdural haematoma (CSDH) has various causes, including trauma, coagulopathies, and intracranial hypotension. However, CSDH associated with extracranial malignancy is rare. Here, we report an extremely rare case of CSDH due to prostate cancer metastasis to a haematoma capsule.

Case Description

A 79-year-old man with a history of prostate cancer had a progressive decline in consciousness during hospitalization for cancer treatment. CSDH was diagnosed from computed tomography (CT) imaging. We urgently performed burr hole drainage, and the patient’s symptoms improved rapidly after surgery. After removing the drainage tube, the patient’s symptoms worsened again, and the repeat head CT suggested recurrence of CSDH. In a second operation, most of the haematoma capsule was excised under craniotomy, and the thickened haematoma capsule was sent for routine pathologic examination. Pathological findings confirmed the metastasis of prostate cancer to the haematoma capsule, which we believed to be related to a rapid recurrence of CSDH. After the second operation, the disease course progressed without CSDH recurrence.

Conclusions

For patients with malignant tumours diagnosed with CSDH, the possibility of metastasis to a haematoma capsule needs to be considered. Burr holes and drainage can easily lead to a rapid relapse. Excision of the haematoma capsule is the key to successful treatment.

Third Ventricle Volume Predicts Functional Outcome in Chronic Subdural Hematoma

OBJECTIVES

There is a lack of evidence demonstrating the utility of computed tomography (CT) to predict chronic subdural hematoma (CSDH) clinical outcomes. We aim to analyze the role of tomographic volumetric analysis in patients with CSDH.

METHODS

We performed a retrospective study of patients undergoing burr-hole craniostomy (BHC) for CSDH over five years at a tertiary care center. Degree of midline shift, radiographic density, subdural hematoma volume, acute blood volume, and third ventricle (3VV) and fourth ventricle (4VV) volume were estimated using semiautomatic segmentation of preoperative CT. Postoperative functional outcome was measured by two endpoints: National Institute of Health Stroke Scale (NIHSS) at discharge and short-term modified Rankin Scale (mRS) at 6-week follow-up. Univariate and multivariate analyses were performed using nonparametric tests. Discriminative capacity and optimal thresholds of independent variables were calculated by means of receiving-operative curves (ROC).

RESULTS

A total of 79 patients were included for analysis with a median age of 78.5 years. Greater preoperative 3VV independently correlated with poor discharge NIHSS (p = .01) and short-term mRS (p = .03). A cutoff value of 0.545 mL demonstrated the highest sensitivity (77.1%) and specificity (88.8%) with an odds ratio for an mRS functional dependence of 9.29 (p = .001).

CONCLUSIONS

Greater preoperative tomographic 3VV independently prognosticates poor discharge NIHSS and 6-week mRS. A threshold 3VV of 0.545 mL can be used to identify patients at higher risk of being dependent at first protocolized follow-up.

Retrospective analysis of 195 surgically treated cases of chronic subdural hematoma

INTRODUCTION

The incidence of chronic subdural hematoma (CSDH) is increasing. This study evaluates the etiologic causes and findings of CSDH and compared unilateral CSDH with bilateral CSDH. This study aims to draw attention to this increasingly prevalent condition.

METHODS

We retrospectively analysed 195 surgically treated cases of CSDH in our clinic between 2008 and 2018.

RESULTS

The average age of the patients was 65.7 ± 19.6 years. The most common symptom was headache (53.3%). The case background was the use of anticoagulant (37.9%), head trauma (34.3%). The hematomas were 28.7% right side, 44.6% left side, and 26.7% bilateral. The mean Glasgow Coma Score (GCS) was 13.4 ± 2.9, early postop 13.8 ± 2.5, and late postop was 14.6 ± 1.1. Postoperative complications included acute subdural hematoma (5.1%), cerebral infarction (1.5%), wound infection (0.5%) and others (13.3%). Re-expansion of the brain were statistically significantly less frequent and impaired consciousness, anticoagulant use, early and late postop thickness were statistically significantly more frequent in patients with bilateral CSDH.

CONCLUSIONS

CSDH is seen more patients of advanced age, those who use anticoagulants, patients with hypertension and diabetes and in patients with a history of head trauma. Prognosis is worse in bilateral CSDH. We estimate that the incidence of CSDH will go up in the future.

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.

Efficacy of the Direct Aspiration-Irrigation Maneuver for the Treatment of Chronic Subdural Hematoma: A Single Hospital's Experience

Objective The traditional methods for managing symptomatic chronic subdural hematoma (CSDH) at our hospital include evacuation via single burr-hole irrigation with continuous closed subdural drainage (SBID). The single burr-hole aspiration and irrigation technique with continuous closed subdural drainage (SBAID) is an attractive alternative method. The goal of this study was to evaluate the radiographic and clinical outcomes of SBAID compared with traditional SBID methods. Methods A database of 51 CSDH patients treated with the SBAID method and 35 CSDH patients treated with the SBID method was compiled, and a retrospective chart review was performed. Information regarding demographics, comorbidities, presenting symptoms, and outcomes were collected. Predictors of recurrence requiring reoperation and other outcomes were analyzed. Results Compared to the patients in the SBID group, the patients in the SBAID group had a shorter mean duration of surgery (56.6±5.6 minutes vs 59.5±4.8 minutes, respectively, P=0.02); a shorter mean interval from procedure to discharge (6.2±1.2 days vs 6.8±1.3 days, respectively, P=0.046); no significant difference in preoperative hematoma volume (106.4±21.7 cm³ vs 101.3±16.3 cm³, respectively, P=0.25); and a smaller subdural space volume 48 hours after the operation (43.6±7.4 cm³ vs 47.4±9.1 cm³, respectively, P=0.03). In addition, symptomatic hematoma recurrence developed in one patient in the SBAID group and five patients in the SBID group (P=0.03). The in-hospital mortality rates of the SBAID and SBID groups were 2% (1 of 51) and 6% (2 of 35), respectively; this difference was not statistically significant (P=0.35). Conclusions The SBAID method results in a remarkably low recurrence rate and good outcomes. This method should be considered for patients presenting with symptomatic CSDHs.

Risk factors for need of reoperation in bilateral chronic subdural haematomas

Background

Chronic subdural haematoma (CSDH) is one of the most common neurosurgical diseases. A subtype of CSDH is bilateral chronic subdural haematoma (bCSDH) which represents 20–25% of patients with CSDH and has a higher recurrence rate. There is no clear consensus on how bCSDH should be treated regarding upfront unilateral- or bilateral evacuation of both haematomas. The purpose of this study was to identify risk factors associated with reoperation of bCSDH.

Methods

A total of 326 patients with radiological evidence of bCSDH were included in this retrospective cohort study where 133 (40.8%) patients underwent primary bilateral evacuation and 193 (59.2%) primary unilateral evacuation. The two centres operated using different surgical approaches. Analyses were performed to identify risk factors associated with reoperation of bCSDH. Reoperation rate was defined as reoperation of CSDH on either side of the hemisphere within 3 months after primary evacuation.

Results

The cohort had a total reoperation rate of 26.4%. Patients which underwent unilateral evacuation had a reoperation rate of 32.1%, and the bilateral group had a reoperation rate of 18.0% (p=0.005). Multivariable logistic regression identified unilateral evacuation (OR 1.91, p=0.022) and complications according to Ibanez (OR 2.20, p=0.032) to be associated with the need of reoperation of bCSDH. One-burr hole craniostomy with active subgaleal drain was primarily performed in bilateral approach (69.4%) whereas patients operated with minicraniotomy with passive subdural drain were primarily operated by unilateral evacuation of the larger symptomatic side (92.8%).

Conclusions

Unilateral evacuation of bCSDH was associated with a higher risk for reoperation than upfront bilateral evacuations in this study. There is a need to further discuss the criteria for uni- or bilateral evacuation since patients are treated differently at different centres.

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.

Chronic Subdural Hematoma (cSDH): A review of the current state of the art

Introduction

Incidence of Chronic Subdural Hematoma (cSDH) is rising worldwide, partly due to an aging population, but also due to increased use of antithrombotic medication. Many recent studies have emerged to address current cSDH management strategies.

Research question

What is the state of the art of cSDH management.

Material and methods

Review.

Results

Head trauma, antithrombotic use and craniocerebral disproportion increase the risk of cSDH development. Most patients present with disorientation, GCS 13–15, and symptoms arising from cortical irritation and increased intracranial pressure. cSDH occurs bilaterally in 9–22%. CT allows assessment of cerebral compression (herniation, hematoma thickness, ventricle collapse, midline shift), hematoma age and presence of membranes, factors that ultimately determine treatment urgency and surgical approach. Recurrence remains the principle complication (9–33%), occurring more commonly with older age and bilateral cSDHs.

Discussion and conclusion

While incompletely understood, it is generally believed that injury in the dural cell layer results in bleeding from bridging veins, resulting in a hematoma formation, with or without a preceding hygroma, in a potential space approximating the junction between the dura and arachnoid. Neovascularization and leaking from the outer membrane are thought to propagate this process. Evidence that MMA embolization may reduce recurrence rates is a potentially exciting new treatment option, but also supports the theory that the MMA is implicated in the cSDH pathophysiology. The use of steroids remains a controversial topic without clear treatment guidelines. cSDH represents a common neurosurgical problem with burr-hole treatment remaining the gold standard, often in conjunction with subgaleal drains. MMA embolization to stop recurrence may represent an important evolution in understanding the pathophysiology of cSDH and improving treatment.

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Incidence of cSDH is rising, partly due to the aging population and increased antithrombotic use.

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cSDH occurs bilaterally in 9–22% of cases.

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Recurrence remains the principle complication and has been estimated at 9–33%.

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Risk factors for recurrence include old age and bilateral cSDHs.

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MMA embolization may reduce recurrence, but its efficacy and target population remain unclear.

Application of Absolute Alcohol in the Treatment of Traumatic Intracranial Hemorrhage via Interventional Embolization of Middle Meningeal Artery

Background: Traumatic brain injury is a common condition in neurosurgery. Traditional methods of treatment include conservative treatment and surgical evacuation using burr-holes or craniotomy; however, studies have reported problems such as high re-expansion rates after conservative treatment of epidural hematoma and high postoperative recurrence rates of subdural hematoma. Solutions to these problems are lacking, and research into new treatment methods is ongoing. Among the potential new treatments, middle meningeal arterial embolization is an option. This study involved patients with acute epidural hematoma and chronic subdural hematoma. The purpose was to evaluate the use and effects of absolute alcohol to embolize the middle meningeal artery to treat intracranial hematoma. Material and Methods: A retrospective description study was 12 cases of intracranial hematoma who treated with absolute alcohol interventional therapy from our hospital between June 2018 and October 2019. Five patients with acute epidural hematoma and seven patients with chronic subdural hematoma were treated using absolute alcohol to embolize the middle meningeal artery. Patients' clinical data, imaging results, surgical results, and prognosis were recorded and analyzed. Results: All patients underwent absolute alcohol embolization of the middle meningeal artery, in combination with burr-hole drainage. All imaging data were confirmed preoperatively. We successfully used absolute alcohol to embolize the middle meningeal artery intraoperatively and confirmed these results by postoperative angiography. All patients achieved symptomatic relief without complications, and no recurrence or re-expansion was seen with follow-up computed tomography. Our study has been registered in the Chinese Clinical Trial Registry (http://www.chictr.org.cn, ChiCTR1800018714). Conclusion: The use of absolute alcohol to embolize the middle meningeal artery could be used as an attempt to treat acute epidural hematoma and chronic subdural hematoma.

Predictors of acute intracranial hemorrhage and recurrence of chronic subdural hematoma following burr hole drainage

Background

To investigate predictors of postoperative acute intracranial hemorrhage (AIH) and recurrence of chronic subdural hematoma (CSDH) after burr hole drainage.

Methods

A multicenter retrospective study of patients who underwent burr hole drainage for CSDH between January 2013 and March 2019.

Results

A total of 448 CSDH patients were enrolled in the study. CSDH recurrence occurred in 60 patients, with a recurrence rate of 13.4%. The mean time interval between initial burr hole drainage and recurrence was 40.8 ± 28.3 days. Postoperative AIH developed in 23 patients, with an incidence of 5.1%. The mean time interval between initial burr hole drainage and postoperative AIH was 4.7 ± 2.9 days. Bilateral hematoma, hyperdense hematoma and anticoagulant drug use were independent predictors of recurrence in the multiple logistic regression analyses. Preoperative headache was an independent risk factor of postoperative AIH in the multiple logistic regression analyses, however, intraoperative irrigation reduced the incidence of postoperative AIH.

Conclusions

This study found that bilateral hematoma, hyperdense hematoma and anticoagulant drug use were independently associated with CSDH recurrence. Clinical presentation of headache was the strongest predictor of postoperative AIH, and intraoperative irrigation decreased the incidence of postoperative AIH.

External validation and modification of the Oslo grading system for prediction of postoperative recurrence of chronic subdural hematoma

Recently, Oslo grading system (OGS) for prediction of recurrence in chronic subdural hematoma (cSDH) was introduced. The aim of the study was to validate and if applicable to modify the grading system. Data of all patients admitted to the Goethe University Hospital between 2016 and 2018 with chronic subdural hematoma were prospectively entered into a database. Dataset of patients with uni- (n = 272) and bilateral cSDH (n = 177) were used for the validation of OGS via logistic regression analysis. Additional predictors were identified and integrated to build a modified OGS (mOGS). Internal validation of the modified OGS was performed using same dataset of patients. The OGS showed a significant good predictive value with correlating increase of recurrence rate depending on the level of score in unilateral cSDH (p = 0.002). Regarding bilateral cSDH, there was no significant predictive value found (p = 0.921). By performing uni- and multivariate analysis, additional predictors for recurrence in uni- and bilateral cSDH were identified and integrated into the score system. Accordingly, the mOGS for unilateral cSDH inherited 4 components: previous OGS with 3 components (OR1.6) and seizure (OR2.5) (0 point, 0% recurrence rate; 1-2 points, 17.4%; 3-4 points, 30.6%; ≥ 5 points, 80%). Regarding bilateral cSDH, the mOGS consisted of 4 components as well: hypodense/gradation subtypes (OR3.3), postoperative unilateral volume > 80 mL (OR7.4), postoperative unilateral air trapping > 80 mL (OR15.3), and seizure (OR5.5) (0 point, 3.6% recurrence rate; 1 point, 30.6%; 2 points, 53.5%; 3 points, 58.3%; ≥ 4 points, 100%). Furthermore, the mOGS was internally verified showing high significant predictive power for recurrent hematoma in uni- (p = 0.004) and bilateral cSDH (p < 0.001). External validation of OGS showed accurate risk stratification of recurrence in unilateral cSDH; however, the validation failed for bilateral cSDH. Thus, mOGS was developed to strengthen its clinical utility and applicability.

Critical Depressed Brain Volume Influences the Recurrence of Chronic Subdural Hematoma after Surgical Evacuation

Recurrence of chronic subdural hematoma (CSDH) frequently occurs after surgical evacuation. However, the value of follow-up postoperative imaging and measuring volumetric factors to predict recurrence are still controversial. Herein, we aimed to assess the optimal timing for follow-up referential imaging and the critical depressed brain volume for CSDH recurrence. A total of 291 patients with CSDH who underwent burr hole craniotomy between January 2012 and December 2018 were consecutively enrolled in this study. Patients’ medical records and radiologic data were evaluated to predict the recurrence and analyzed using receiver operating characteristics (ROC) and binary logistic regression. Of the 291 patients, 29 (10.0%) showed recurrence after surgical evacuation. Based on ROC analysis, comparisons of depressed brain volume pre-operation, 24 h post-operation, and 7 days post-operation showed that the depressed brain volume at 7 days after surgery featured the largest area under the curve (AUC: 0.768, 95% CI, 0.709–0.811). The cut-off value of the depressed brain volume on postoperative day 7 was 51.6 cm³; this value predicted the recurrence of CSDH with a sensitivity and specificity of 79.3% and 67.9%, respectively. In the multivariate analysis, the depressed brain volume (>50 cm³) at 7 days was the sole significant risk factor related to the recurrence of CSDH in this series (OR: 6.765, 95% CI, 2.551–17.942, p < 0.001). The depressed brain volume > 50 cm³ visualized on CT scans at postoperative 7 day is the critical volume affecting recurrence of CSDHs. This result could be helpful carrying in patients with CSDH to determine the proper postoperative treatment strategy.

CT-Based Quantitative Analysis for Pathological Features Associated With Postoperative Recurrence and Potential Application Upon Artificial Intelligence: A Narrative Review With a Focus on Chronic Subdural Hematomas

Chronic subdural hematomas (CSDHs) frequently affect the elderly population. The postoperative recurrence rate of CSDHs is high, ranging from 3% to 20%. Both qualitative and quantitative analyses have been explored to investigate the mechanisms underlying postoperative recurrence. We surveyed the pathophysiology of CSDHs and analyzed the relative factors influencing postoperative recurrence. Here, we summarize various qualitative methods documented in the literature and present our unique computer-assisted quantitative method, published previously, to assess postoperative recurrence. Imaging features of CSDHs, based on qualitative analysis related to postoperative high recurrence rate, such as abundant vascularity, neomembrane formation, and patent subdural space, could be clearly observed using the proposed quantitative analysis methods in terms of mean hematoma density, brain re-expansion rate, hematoma volume, average distance of subdural space, and brain shifting. Finally, artificial intelligence (AI) device types and applications in current health care are briefly outlined. We conclude that the potential applications of AI techniques can be integrated to the proposed quantitative analysis method to accomplish speedy execution and accurate prediction for postoperative outcomes in the management of CSDHs.

Variation of Ventricular Size after Surgical Treatment of Chronic Subdural Hematoma

Background

Surgical removal is the treatment of choice for chronic subdural hematoma (CSDH). Despite clinical improvement after surgery, computed tomography (CT) scan control often showed residual collection, which may discuss the possibility of failed surgery. The aim of this study is the assessment of ventricular size before and after surgery and to study its relation with residual hematoma.

Methods

In this prospective study (2013-2016), 63 patients who had burr-hole drainage of CSDH were sequentially allocated to either two groups; Group 1 with CT scan control under the 3^rd day of surgery and Group 2 with delayed CT scan control (from 4^th to 7^th day). Linear measure of ventricular size was assessed by Evans' index. We reviewed and analyzed the data between both groups.

Results

There were 33 patients in Group 1 and 30 patients in Group 2. Preoperatively, the average thickness of hematoma was 20.5 mm in Group 1 versus 19.9 mm in Group 2 (P = 0.67); the mean midline shift was 8.5 mm in each group; Evans' index was 26.7% in Group 1 and 27% in Group 2 (P = 0.7). Postoperatively, the mean thickness of the residual hematoma was 7.7 mm in Group 1 and 8.4 mm in Group 2 (P = 0.57); the mean midline shift was 3.3 mm in Group 1 and 1.9 mm in Group 2 (P = 0.08); Evan's index was 28.5% in Group 1 and 32.1% in Group 2 (P = 0.002).

Conclusion

The adoption of Evans' index, for assessing the variation of ventricular size after surgery, by neurosurgeons appears to be a good and simple method for evaluation and following the success of surgical removal of CSDH, despite the observation of some residual collection in early CT scan control.

A Reliable Grading System for Prediction of Chronic Subdural Hematoma Recurrence Requiring Reoperation After Initial Burr-Hole Surgery

BACKGROUND

There is no widely adopted grading system for the prediction of postoperative recurrence requiring reoperation (RrR) in patients with chronic subdural hematoma (CSDH).

OBJECTIVE

We developed a CSDH grading system to predict RrR based on predictive characteristics that can be objectively assessed at the time of first presentation and initial surgery.

METHODS

Prospectively collected data from 107 consecutive surgical patients with CSDH were reviewed. Predictors of RrR were identified via logistic and lasso regression analyses. A prognostic CSDH grading system was proposed, with the weighing of predictors based on strength of association. The scoring system was then applied to the same set of patients in our database for internal validation.

RESULTS

The strongest predictors of RrR were an isodense or hyperdense lesions and laminar or separated lesions, and a postoperative CSDH cavity volume greater than 200 mL. The moderate predictors of RrR were a postoperative CSDH cavity volume of 80 to 200 mL and a preoperative CSDH volume greater than 130 mL. According to the prognostic CSDH grading system, no patients with a score of 0 points had RrR. RrR was observed in 6% of patients with a score of 1 to 2 points, 30% of patients with a score of 3 to 4 points, and 63% of patients with a score of 5 points (ie, the maximum score). The rate of RrR increased steadily with increases in the prognostic CSDH grading score (P < .001).

CONCLUSION

The prognostic CSDH grading system is an applicable tool for RrR risk stratification in patients with CSDH.

Atorvastatin May Attenuate Recurrence of Chronic Subdural Hematoma

OBJECTIVE

Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a substantial recurrence rate. Atorvastatin may reduce CSDH via its anti-inflammatory and pro-angiogenesis effects, but its effectiveness for preventing recurrent CSDH has never been explored. We hypothesized that atorvastatin is effective in reducing recurrence of CSDH after surgery and identified determining factors predictive of hematoma recurrence.

METHODS

A prospective study was conducted in 168 surgical cases of CSDH.All patients were randomly assigned to the group treated with atorvastatin or control group. Clinically relevant data were compared between two groups, and subsequently between the recurrence and non-recurrence patients. Multiple logistic regression analysis of the relationship between atorvastatin treatment and the recurrence using brain atrophy, septated and bilateral hematoma was performed.

RESULTS

Atorvastatin group conferred an advantage by significantly decreasing the recurrence rate (P = 0.023), and patients managed with atorvastatin also had a longer time-to-recurrence (P = 0.038). Admission brain atrophy and bilateral hematoma differed significantly between the recurrence and non-recurrence patients (P = 0.047 and P = 0.045). The results of logistic regression analysis showed that atorvastatin significantly reduced the probability of recurrence; severe brain atrophy and bilateral hematoma were independent risk factors for recurrent CSDH.

CONCLUSIONS

Atorvastatin administration may decrease the risks of recurrence.Patients with severe brain atrophy and bilateral CSDH are prone to the recurrence.

Chronic subdural hematoma

Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions. There is lack of uniformity in the treatment of CSDH amongst surgeons in terms of various treatment strategies. Clinical presentation may vary from no symptoms to unconsciousness. CSDH is usually diagnosed by contrast-enhanced computed tomography scan. Magnetic resonance imaging (MRI) scan is more sensitive in the diagnosis of bilateral isodense CSDH, multiple loculations, intrahematoma membranes, fresh bleeding, hemolysis, and the size of capsule. Contrast-enhanced CT or MRI could detect associated primary or metastatic dural diseases. Although definite history of trauma could be obtained in a majority of cases, some cases may be secondary to coagulation defect, intracranial hypotension, use of anticoagulants and antiplatelet drugs, etc., Recurrent bleeding, increased exudates from outer membrane, and cerebrospinal fluid entrapment have been implicated in the enlargement of CSDH. Burr-hole evacuation is the treatment of choice for an uncomplicated CSDH. Most of the recent trials favor the use of drain to reduce recurrence rate. Craniotomy and twist drill craniostomy also play a role in the management. Dural biopsy should be taken, especially in recurrence and thick outer membrane. Nonsurgical management is reserved for asymptomatic or high operative risk patients. The steroids and angiotensin converting enzyme inhibitors may also play a role in the management. Single management strategy is not appropriate for all the cases of CSDH. Better understanding of the nature of the pathology, rational selection of an ideal treatment strategy for an individual patient, and identification of the merits and limitations of different surgical techniques could help in improving the prognosis.

Quantitative assessment of brain shifting in the late phase postevacuation in unilateral and bilateral chronic subdural hematomas

AIM OF THE STUDY

Recurrence is more common in bilateral chronic subdural hematomas (CSDHs) than in unilateral. Our aim was to quantitatively compare the late phase of brain shifting postevacuation in unilateral and bilateral CSDHs.

MATERIALS AND METHODS

We reviewed computed tomography (CT) scans and medical records of consecutive patients with CSDHs who underwent burr hole drainage. CT scan images (preoperative and postoperative days [PODs] 30 and 60) were imported to Adobe Photoshop, and temporal and spatial changes in brain shifting between PODs 30 and 60, and also the subdural space on POD 60, were analyzed.

RESULTS

The bilateral group exhibited a significantly greater late phase of brain shifting than the unilateral group between PODs 30 and 60 (P < 0.001). The median late phase of brain shifting of the bilateral group was 8.9 mm (interquartile range [IQR]: 8.3-9.0 mm) between PODs 30 and 60, while that of the unilateral group was 1.8 mm (IQR: 1.3-2.5 mm).

CONCLUSIONS

The postevacuation late phase of brain shifting is statistically greater in bilateral CSDHs than in unilateral CSDHs, which might facilitate bridging vein tearing and consequent rebleeding. This may be one factor accounting for the higher recurrence rate of bilateral CSDHs.

Superficial subarachnoid cerebrospinal fluid space expansion after surgical drainage of chronic subdural hematoma

BACKGROUND

The present study examined the computed tomography (CT) findings after surgery and overnight drainage for chronic subdural hematoma (CSDH) to clear the significance of inner superficial subarachnoid CSF space and outer subdural hematoma cavity between the brain surface and the inner skull.

METHODS

A total of 73 sides in 60 patients were evaluated. Head CT was performed on the day after surgery and overnight drainage (1st CT), within 3 weeks of surgery (2nd CT), and more than 3 weeks after surgery (3rd CT). Subdural and subarachnoid spaces were identified to focus on density of fluid, shape of air collection, and location of silicone drainage tube, etc. Cases with subdural space larger than the subarachnoid CSF space were classified as Group SD between the brain and the skull. Cases with subarachnoid CSF space larger than the subdural space were classified as Group SA. Cases with extremely thin (<3 mm) spaces between the brain and the skull were classified as Group NS.

RESULTS

Group SA, SD, and NS accounted for 31.9, 55.6 and 12.5% of cases on the 1st CT. No statistical differences were found between Groups SA, SD, and NS in any clinical factors, including recurrence. Group SA were found significantly more on 1st CT than on 2nd and 3rd CT.

CONCLUSIONS

Subarachnoid CSF space sometimes expands between the brain and skull on CT after surgical overnight drainage. Expansion of the arachnoid space may be a passive phenomenon induced by overnight drainage and delayed re-expansion of the brain parenchyma.

Chronic subdural haematoma: modern management and emerging therapies

Chronic subdural haematoma (CSDH) is one of the most common neurological disorders, and is especially prevalent among elderly individuals. Surgical evacuation is the mainstay of management for symptomatic patients or haematomas exerting significant mass effect. Although burr hole craniostomy is the most widely practised technique worldwide, approximately 10-20% of surgically treated patients experience postoperative recurrence necessitating reoperation. Given the increasing incidence of CSDH in a growing elderly population, a need exists for refined techniques that combine a minimally invasive approach with clinical efficacy and cost-effectiveness. In addition, nonsurgical treatment modalities, such as steroids, are attracting considerable interest, as they have the potential to reduce postoperative recurrence or even replace the need for surgery in selected patients. This Review provides an overview of the contemporary management of CSDH and presents considerations regarding future approaches that could further optimize patient care and outcomes.

Volume of chronic subdural haematoma: is it one of the radiographic factors related to recurrence?

BACKGROUND

Recurrence of chronic subdural haematoma (CSDH) is a significant issue in neurosurgical practice, and to distinguish individuals at high risk is important. In this study, we aim to clarify the relationship between quantitative haematoma volume and recurrence of CSDH.

METHODS

For this two-year retrospective study, 94 patients with CSDH were enrolled and all underwent burr-hole craniostomy with closed-system drainage. The volume of haematoma before surgery was quantitatively analysed by computed tomography (CT) of the brain. The patients were subdivided into 2 groups based on whether recurrence of CSDH was present or not. We investigated the intergroup differences in the volume of haematoma and other radiographic parameters.

RESULTS

Recurrence of CSDH was identified in 13 of 94 patients (14%). Univariable analysis of CT features revealed significant differences in the volume of haematoma, bilateral cerebral convexity, and layering of the haematoma. To adjust for the confounding effect, these 3 parameters were entered into multivariable logistic regression analysis. Ultimately, neither the volume of haematoma (p=0.449) or bilateral cerebral convexity (p=0.123) was relevant in this model. Only the presence of layering of the haematoma was independently associated with recurrence of CSDH (p=0.009).

CONCLUSION

The volume of CSDH is not related to recurrence in patients undergoing burr-hole craniostomy with closed-system drainage. Layering of the haematoma was the only independent risk factor on CT images for recurrence of CSDH in our series.

Quantitative assessment of post-operative recurrence of chronic subdural haematoma using mean haematoma density

PURPOSE

The purpose of this study was to establish a quantitative method with which to assess the post-operative recurrence of chronic subdural haematoma (CSDH).

METHODS

CT scans were reviewed from 44 consecutive patients with CSDHs who underwent burr hole drainage between July 2008 and January 2012. The area of the haematoma was quantified according to the mean haematoma density (MHD) using computer-based image analysis of pre-operative brain CT scans. MHD as well as other variables of patients with and without post-operative recurrences was statistically compared.

RESULTS

Post-operative recurrence was noted in six of the 44 patients that underwent surgical procedures. Among these variables, high MHD, separated type and bilateral and skull base involvement of CSDHs were shown to be significantly related to post-operative recurrence (p < 0.05). Controlling for separated type in logistic regression analysis revealed the OR of MHD as statistically significant indicators with a p value of less than 0.05 (OR = 1.243; 95% CI = 1.003-1.54).

CONCLUSION

This study provides statistical proof that MHD is a significant, independent, prognostic factor for the post-operative recurrence of CSDH. As such, consideration of MHD could aid in the prediction of post-operative prognosis of CSDHs.

Double-layer appearance after evacuation of a chronic subdural hematoma

OBJECTIVE

To investigate the reason for and the course of the double-layer appearance in the postoperative computed tomographies (CTs) of chronic subdural hematoma (CSDHs).

METHODS

We reviewed CSDH cases that were operated on during the last 3 years, between January 2008 and December 2010. We checked the preoperative, early postoperative, and late postoperative CTs of these patients. We investigated the relationship between the formation of a double-layer appearance and the prognoses and demographic characteristics of the patients.

RESULTS

Our database included 119 cases. A double-layer appearance was found in the postoperative CTs of 34 cases. The mean age of double-layer cases was older (72.5 ± 12.1) than that of the remaining 85 cases (63.1 ± 17.8). We did not find any relationship between the double-layer appearance and the reoperation/recurrence/death rates.

CONCLUSIONS

The double-layer appearance after evacuation of a CSDH might be caused by enlargement of the subarachnoid space and is not related to the presence of any residual hematoma. This appearance is not considered as a reason for reoperation.

A simplified technique for polymethyl methacrylate cranioplasty: combined cotton stacking and finger fracture method

PRIMARY OBJECTIVE

Polymethyl methacrylate (PMMA) is one of the most frequently used cranioplasty materials. However, limitations exist with PMMA cranioplasty including longer operative time, greater blood loss and a higher infection rate. To reduce these disadvantages, it is proposed to introduce a new surgical method for PMMA cranioplasty.

RESEARCH DESIGN

Retrospective review of nine patients who received nine PMMA implants using combined cotton stacking and finger fracture method from January 2008 to July 2011.

METHODS AND PROCEDURES

The definitive height of skull defect was quantified by computer-based image analysis of computed tomography (CT) scans. Aesthetic outcomes as measured by post-reduction radiographs and cranial index of symmetry (CIS), cranial nerve V and VII function and complications (wound infection, hardware extrusions, meningitis, osteomyelitis and brain abscess) were evaluated.

MAIN OUTCOMES AND RESULTS

The mean operation time for implant moulding was 24.56 ± 4.6 minutes and 178.0 ± 53 minutes for skin-to-skin. Average blood loss was 169 mL. All post-operative radiographs revealed excellent reduction. The mean CIS score was 95.86 ± 1.36%, indicating excellent symmetry.

CONCLUSIONS

These results indicate the safety, practicability, excellent cosmesis, craniofacial symmetry and stability of this new surgical technique.