Risk of recurrence of subdural hematoma after EMMA vs surgical drainage - Systematic review and meta-analysis

Therapeutic efficacy of drilling drainage combined with intraoperative middle meningeal artery occlusion in the management of chronic subdural hematoma: a clinical study

BACKGROUND

The bone holes in the skull during surgical drainage were accurately located at the site of the MMA. The MMA was severed, and the hematoma was removed intraoperatively; furthermore, surgical drainage removed the pathogenic factors of CSDH. This study aimed to describe and compare the results of the new treatment with those of traditional surgical drainage, and to investigate the relevance of this approach.

METHODS

From December 2021 to June 2023, 72 patients were randomly assigned to the observation group and the control group. The control group was treated with traditional surgical drainage, while the observation group was treated with DSA imaging to accurately locate the bone holes drilled in the skull on the MMA trunk before traditional surgical drainage. The MMA trunk was severed during the surgical drainage of the hematoma. The recurrence rate, time of indwelling drainage tube, complications, mRS, and other indicators of the two groups were compared, and the changes of cytokine components and imaging characteristics of the patients were collected and analyzed.

RESULTS

Overall, 27 patients with 29-side hematoma in the observation group and 45 patients with 48-side hematoma in the control group were included in the study. The recurrence rate was 0/29 in the observation group and 4/48 in the control group, indicating that the recurrence rate in the observation group was lower than in the control group (P = .048). The mean indwelling time of the drainage tube in the observation group was 2.04 ± 0.61 days, and that in the control group was 2.48 ± 0.61 days. The indwelling time of the drainage tube in the observation group was shorter than in the control group (P = .003). No surgical complications were observed in the observation group or the control group. The differences in mRS scores before and after operation between the observation group and the control group were statistically significant (P < .001). The concentrations of cytokine IL6/IL8/IL10/VEGF in the hematoma fluid of the observation and control groups were significantly higher than those in venous blood (P < .001). After intraoperative irrigation and drainage, the concentrations of cytokines (IL6/IL8/IL10/VEGF) in the subdural hematoma fluid were significantly lower than they were preoperatively. In the observation group, the number of MMA on the hematoma side (11/29) before STA development was higher than that on the non-hematoma side (1/25), and the difference was statistically significant (P = .003).

CONCLUSION

In patients with CSDH, accurately locating the MMA during surgical trepanation and drainage, severing the MMA during drainage, and properly draining the hematoma, can reduce the recurrence rate and retention time of drainage tubes, thereby significantly improving the postoperative mRS Score without increasing surgical complications.

In vitro comparison of middle meningeal artery embolization with Squid liquid embolic agent and Contour polyvinyl alcohol particles

BACKGROUND

Liquid embolic agents and polyvinyl alcohol (PVA) particles have been used for the embolization of the middle meningeal artery (MMA) for the treatment of chronic subdural hematomas. However, the vascular penetration and distribution of these embolic agents have not yet been compared. The current study compares distribution of a liquid embolic agent (Squid) to PVA particles (Contour) in an in vitro model of the MMA.

METHODS

MMA models were embolized with Contour PVA particles 45-150 µm, Contour PVA particles 150-250 µm, and Squid-18 liquid embolic agent (n=5 each). The models were scanned and every vascular segment with embolic agent was manually marked on the images. Embolized vascular length as a percentage of control, average embolized vascular diameter, and embolization time were compared between the groups.

RESULTS

The 150-250 µm Contour particles primarily accumulated close to the microcatheter tip, yielding proximal branch occlusions. The 45-150 µm Contour particles achieved a more distal distribution, but in a patchy segmental pattern. However, the models embolized with Squid-18 had a consistently distal, near-complete and homogenous distribution. Embolized vascular length was significantly higher (76±13% vs 5±3%, P=0.0007) and average embolized vessel diameter was significantly smaller (405±25 µm vs 775±225 µm, P=0.0006) with Squid than with Contour. Embolization time with Squid was also lower (2.8±2.4 min vs 6.4±2.7 min, P=0.09).

CONCLUSIONS

Squid-18 liquid results in a considerably more consistent, distal and homogeneous pattern of embolysate distribution than Contour PVA particles in an anatomical model of the MMA tree.

Adjuvant Tranexamic Acid for Reducing Postoperative Recurrence of Chronic Subdural Hematoma in the Elderly: A Systematic Review and Meta-Analysis

BACKGROUND

Chronic subdural hematoma (CSDH) is a frequently encountered neurosurgical disease among the elderly. The mainstay treatment involves surgical evacuation, but recurrence rates of approximately 13% pose complications. Adjuvant treatments, including tranexamic acid (TXA), have been explored, yet consensus on their efficacy and safety in elderly patients remains uncertain. The study aims to examine the role of TXA as adjunctive therapy in reducing CSDH recurrence and explore any potential association between TXA use and thrombotic events in this patient population.

METHODS

The systematic review and meta-analysis adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Cochrane Handbook standards, searching databases up to July 2023 for randomized controlled trials and propensity-matched cohorts evaluating adjuvant TXA. The primary outcome was CSDH recurrence, and the secondary outcome was thrombosis risk, measured as relative risks.

RESULTS

A total of 6 studies were included, comprising 1403 patients with CSDH who underwent surgical treatment. Four studies were randomized controlled trials, while the other 2 were propensity-matched cohorts. The overall pooled relative risk for CSDH recurrence in the TXA group compared to the control group was 0.41 (95% confidence interval [0.29-0.59], P < 0.01), indicating a significant reduction in recurrence with TXA treatment.

CONCLUSIONS

In conclusion, our study indicates that adjuvant TXA may help reduce CSDH recurrence in elderly patients undergoing surgical treatment. However, the study has limitations and there is a need for further research to validate these findings.

Administration of Tranexamic Acid After Burr Hole Craniotomy Reduced Postoperative Recurrence of Chronic Subdural Hematoma in a Japanese Regional Population

BACKGROUND

Although tranexamic acid (TXA) has occasionally been used to prevent postoperative recurrence of chronic subdural hematoma (CSDH) after burr hole craniotomy (BC), robust evidence of its efficacy has been lacking.

OBJECTIVE

To assess the efficacy and safety of postoperative oral administration of TXA after BC for CSDH among the elderly.

METHODS

This retrospective, propensity score-matched cohort study was carried out with a large Japanese local population-based longitudinal cohort in the Shizuoka Kokuho Database between April 2012 and September 2020. Patients included were age 60 years or older and had undergone BC for CSDH but were not undergoing dialysis. Covariates were collected from records of the preceding 12 months from the month of first BC, and patients were followed up for 6 months after surgery. The primary outcome was repeat surgery, and the secondary outcome was death or the onset of thrombosis. Data on postoperative TXA administration were collected and compared with controls using propensity score matching.

RESULTS

Of the 8544 patients who underwent BC for CSDH, 6647 were included, with 473 placed in the TXA group and 6174 placed in the control group. After 1:1 matching, repeated BC was found to have been performed in 30 of 465 patients (6.5%) in the TXA group and in 78 of 465 patients (16.8%) in the control group (relative risk, 0.38; 95% CI, 0.26-0.56). No significant difference was observed for death or the onset of thrombosis.

CONCLUSION

Oral administration of TXA reduced the occurrence of repeat surgery after BC for CSDH.

A systematic review of middle meningeal artery embolization for minimally symptomatic chronic subdural haematomas that do not require immediate evacuation

Introduction

Embolization of the Middle Meningeal Artery (EMMA) is an emerging treatment option for patients with Chronic Subdural Haematoma (CSDH).

Questions

(1) Can EMMA change the natural history of untreated minimally symptomatic CSDH which do not require immediate evacuation? (2) What is the role of EMMA in the prevention of recurrence following surgical treatment? (3) Can the procedure be performed under local anaesthetic?

Material and methods

Systematic literature review. No randomised clinical trials available on EMMA for meta-analysis.

Results

Six unique large cohorts with more than 50 embolisations were identified (evidence: 3b-4). EMMA can control the progression of surgically naïve CSDH in 91.1-100% of the patients, in which haematoma expansion is halted, or the lesion decreases and resolves. Treatment failure requiring surgery occurs in 0-4.1% of the patients having EMMA as the primary and only treatment. Treatment failure requiring surgery goes up slightly to 6.8% if post-surgical patients are included. When EMMA is used as postsurgical adjunctive the risk of recurrence is 1.4-8.9% compared to 10-20% in surgical series. EMMA has minimal morbidity and it is feasible under local anaesthesia or slight sedation in the majority of cases.

Conclusion

There is cumulative low-quality evidence in the literature that EMMA may be able to modify the natural course of the disease. It appears effective in controlling progression of CSDHs in patients having it as a primary standing alone treatment and it reduces the risk of recurrence and the need for surgical intervention in refractory postsurgical cases or as a postsurgical adjunctive treatment with minimal morbidity (recommendation: C).

Middle meningeal artery embolization for treatment of chronic subdural hematomas: does selection of embolized branches affect outcomes?

OBJECTIVE

Middle meningeal artery (MMA) embolization (MMAE) is a new therapeutic modality for chronic subdural hematoma (cSDH). There is limited evidence comparing various MMAE procedural techniques, resulting in significant variations in technique and procedural planning. The objective of this study was to compare outcomes of MMAE by the number and location of MMA branches that were embolized.

METHODS

A single-center retrospective study of patients with cSDH treated by MMAE was conducted. Clinical outcomes, need for re-intervention, and changes in hematoma size were compared between different MMAE techniques.

RESULTS

Ninety-four cSDHs in 78 patients were included. Embolization of the proximal trunk only, distal branches only, or proximal trunk plus distal branches resulted in similar rates of need for rescue surgery (7.4%, 13.0%, and 6.8%, respectively; p = 0.66) and rates of reducing the volume of the hematoma by at least 50% (74.1%, 80.0%, and 77.5%, respectively; p = 0.88). Embolization of only one branch had similar outcomes to embolization of more than one branch, as rescue surgery rates were 9.3% and 7.8% (p = 0.80), and rates ≥ 50% volume reduction were 75.6% and 78.3% (p = 0.76), respectively. Selective embolization of the dominant MMA branch was not associated with significantly different outcomes.

CONCLUSIONS

Outcomes of distal, proximal, or combined proximal and distal MMAE in cSDH are not significantly different. Embolization of more than one branch is not associated with improved treatment efficacy. Arguably, targeting any location in the MMA provides sufficient flow restriction to enable spontaneous hematoma resolution. Accordingly, a technical planning algorithm for cSDH MMAE is suggested.

Middle Meningeal Artery Embolization Versus Conventional Management for Patients With Chronic Subdural Hematoma: A Systematic Review and Meta-Analysis

BACKGROUND

The results from studies that compare middle meningeal artery (MMA) embolization vs conventional management for patients with chronic subdural hematoma are varied.

OBJECTIVE

To conduct a systematic review and meta-analysis on studies that compared MMA embolization vs conventional management.

METHODS

Medline, PubMed, and Embase databases were searched. Primary outcomes were treatment failure and surgical rescue; secondary outcomes were complications, follow-up modified Rankin scale > 2, mortality, complete hematoma resolution, and length of hospital stay (day). The certainty of the evidence was determined using the GRADE approach.

RESULTS

Nine studies yielding 1523 patients were enrolled, of which 337 (22.2%) and 1186 (77.8%) patients received MMA embolization and conventional management, respectively. MMA embolization was superior to conventional management for treatment failure (relative risk [RR] = 0.34 [0.14-0.82], P = .02), surgical rescue (RR = 0.33 [0.14-0.77], P = .01), and complete hematoma resolution (RR = 2.01 [1.10-3.68], P = .02). There was no difference between the 2 groups for complications (RR = 0.93 [0.63-1.37], P = .72), follow-up modified Rankin scale >2 (RR = 0.78 [0.449-1.25], P = .31), mortality (RR = 1.05 [0.51-2.14], P = .89), and length of hospital stay (mean difference = -0.57 [-2.55, 1.41], P = .57). For MMA embolization, the number needed to treat for treatment failure, surgical rescue, and complete hematoma resolution was 7, 9, and 3, respectively. The certainty of the evidence was moderate to high for primary outcomes and low to moderate for secondary outcomes.

CONCLUSION

MMA embolization decreases treatment failure and the need for surgical rescue without furthering the risk of morbidity and mortality. The authors recommend considering MMA embolization in the chronic subdural hematoma management.

Clinical Outcome and Recurrence Risk of Chronic Subdural Hematoma After Surgical Drainage

Introduction Chronic subdural hematoma (CSDH) is one of the most encountered neurosurgical cases. CSDH is defined as the accumulation of liquified blood products in the space between the dura and the arachnoid. A reported incidence of 17.6/100,000/year has more than doubled in the past 25 years in parallel with an aging population. Surgical drainage remains the mainstay of treatment, yet it is challenged by variable recurrence risks. Less invasive embolization methods of the middle meningeal artery (EMMA) could reduce the recurrence risks. Before adopting a newer treatment (EMMA), it is prudent to establish the outcomes from surgical drainage. The purpose of this study is to assess the clinical outcome and recurrence risk in surgically treated CSDH patients in our center. Methods A retrospective search of our surgical database was done to identify CSDH patients undergoing surgical drainage in the year 2019-2020. Demographic and clinical details were collected, and quantitative statistical analysis was performed. Peri-procedural radiographic information and follow-ups were also included as per the standard of care. Results A total of 102 patients (mean age: 69 years; range: 21-100 years; male: 79) with CSDH underwent surgical drainage with repeat surgery in 13.7% of the patients (n=14). Peri-procedural mortality and morbidity were 11.8%(n=12) and 19.6% (n=20), respectively. Overall, among our patient population, recurrence was seen in 22.55% (n=23). The mean total hospital stay was 10.6 days. Conclusions Our retrospective cohort study showed an institutional CSDH recurrence risk of 22.55%, in keeping with what is reported in the literature. This baseline information is important for a Canadian setting and provides a basis for comparison for future Canadian trials.

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.

Management of Chronic Subdural Hematoma: A Systematic Review and Component Network Meta-analysis of 455 Studies With 103 645 Cases

BACKGROUND

Chronic subdural hematoma (CSDH) is a common neurosurgical condition with a high risk of recurrence after treatment.

OBJECTIVE

To assess and compare the risk of recurrence, morbidity, and mortality across various treatments for CSDH.

METHODS

A systematic review and meta-analysis was performed. PubMed/MEDLINE, EMBASE, SCOPUS, and Web of Science were searched from January 01, 2000, to July 07, 2021. The primary outcome was recurrence, and secondary outcomes were morbidity and mortality. Component network meta-analyses (CNMAs) were performed for surgical and medical treatments, assessing recurrence and morbidity. Incremental risk ratios (iRRs) with 95% CIs were estimated for each component.

RESULTS

In total, 12 526 citations were identified, and 455 studies with 103 645 cases were included. Recurrence occurred in 11 491/93 525 (10.8%, 95% CI 10.2-11.5, 418 studies) cases after surgery. The use of a postoperative drain (iRR 0.53, 95% CI 0.44-0.63) and middle meningeal artery embolization (iRR 0.19, 95% CI 0.05-0.83) reduced recurrence in the surgical CNMA. In the pharmacological CNMA, corticosteroids (iRR 0.47, 95% CI 0.36-0.61) and surgical intervention (iRR 0.11, 95% CI 0.07-0.15) were associated with lower risk. Corticosteroids were associated with increased morbidity (iRR 1.34, 95% CI 1.05-1.70). The risk of morbidity was equivalent across surgical treatments.

CONCLUSION

Recurrence after evacuation occurs in approximately 10% of cSDHs, and the various surgical interventions are approximately equivalent. Corticosteroids are associated with reduced recurrence but also increased morbidity. Drains reduce the risk of recurrence, but the position of drain (subdural vs subgaleal) did not influence recurrence. Middle meningeal artery embolization is a promising treatment warranting further evaluation in randomized trials.

Valve-controlled chronic subdural hematoma drainage: A feasibility study

INTRODUCTION

Pneumocephalus after chronic subdural hematoma (CSDH) evacuation is a potential predictor of hematoma recurrence.

RESEARCH QUESTION

To study the feasibility and safety of a novel CSDH evacuation technique using a valve-controlled method to avoid pneumocephalus.

MATERIAL AND METHODS

In a retrospective case series, we evacuated CSDH using very low-pressure valve-controlled drains and recorded the neurological, radiological, and functional outcomes. Patients with primary CSDH, without previous neurosurgical intervention, and who did not receive antiplatelet or anticoagulant therapy the week prior to the index surgery, were included in the study. Exclusion criteria were the evacuation with other treatment techniques and incomplete data files. Patients were assessed according to the Bender grading system to record the neurological status. The hematoma volume was estimated using the formula for ellipsoid volumes.

RESULTS

Thirty-six patients with a mean age of 73 years (±9 years) fulfilled our eligibility criteria. Our technique was effective since it decreased the CSDH volume from 141 ​ml (IQR 97 ​ml) to 20.6 ​ml (IQR 26.59 ​ml; p ​< ​0.001) and improved the neurological status according to the Bender grading system from two (IQR 0.25) to 1 (IQR 0). However, pneumocephalus and hematoma recurrence occurred in one case each (2.8%). At six months, all patients returned to their previous status, except for two patients (5.6%) who died due to irrelevant pathologies.

CONCLUSIONS

Valve-controlled CSDH evacuation aiming to decrease the postoperative pneumocephalus and hematoma recurrence constitutes an effective and safe alternative. However, larger randomized controlled studies are required to establish its role in CSDH management.

Swedish trial on embolization of middle meningeal artery versus surgical evacuation in chronic subdural hematoma (SWEMMA)—a national 12-month multi-center randomized controlled superiority trial with parallel group assignment, open treatment allocation and blinded clinical outcome assessment

Background

Chronic subdural hematoma (cSDH) is one of the most common neurosurgical disorders and the incidence is rising. The routine treatment is neurosurgical hematoma evacuation, which is associated with recurrence rates up to 10–25%. In recent years, endovascular embolization of the middle meningeal artery (eMMA) has garnered much attention due to recurrence rates as low as < 5%. Several randomized controlled trials are planned or ongoing. In most of these trials, conventional neurosurgical treatment with or without adjunctive endovascular embolization is compared. The proposed trial aims to conduct a head-to-head comparison between neurosurgical and endovascular treatment as stand-alone treatments.

Methods

The trial is academically driven and funded within existing public healthcare systems and infrastructure. Patients with uni- or bilateral cSDH, presenting with mild-to moderate symptoms, and admitted to neurosurgery on clinical grounds will be offered participation. Subjects are randomized 1:1 between conventional neurosurgical treatment (control) and endovascular embolization of the middle meningeal artery (intervention). Primary endpoint is reoperation due to clinically and/or radiologically significant recurrence within 3 months. Secondary endpoints include safety, technical success rate, neurological disability, and quality of life.

Discussion

There are mounting retrospective data suggesting eMMA, as sole treatment or as an adjunctive to neurosurgery for cSDH, is safe and effective with a reoperation rate lower than neurosurgical hematoma evacuation alone. If randomized controlled trials confirm these findings, there is a potential for a paradigm shift in the treatment of cSDH where a minimally invasive procedure can replace open surgery in a large and oftentimes old and fragile patient cohort.

Trial registration

ClinicalTrials.gov, ClinicalTrials.gov Identifier NCT05267184. Registered March 4, 2022.

Middle Meningeal Artery Embolization with Isolated Use of Coils for Treatment of Chronic Subdural Hematomas: A Case Series

BACKGROUND

Middle meningeal artery embolization (MMAE) is a novel approach for treatment of chronic subdural hematoma (cSDH). Studies comparing different procedural techniques for MMAE are lacking. It is unclear whether isolated use of coils results in suboptimal outcomes compared to when particle embolization is also performed. The objectives of this study are to describe the outcomes of coil-only MMAE and compare them with those of combined use of coils and particles.

METHODS

A single-institution retrospective study of cSDH cases treated by MMAE was performed. Clinical outcomes, need for rescue surgery, and changes in hematoma's size were compared between the coil-only and coil + particle groups.

RESULTS

Ninety-four hematomas in 78 patients were included. Twelve cases were treated by a coil-only MMAE procedure, often due to presence of dangerous ophthalmic collaterals. No treatment-related complications were observed in the coil-only group. There was no significant difference between the coil-only and coil + particle groups in baseline hematoma axial thickness, volume, midline shift, and duration of follow-up. The rate of need for rescue surgery was similar between the 2 groups (8.3% vs. 8.5%; P = 0.98). Coiling alone resulted in a similar percentage of reduction in cSDH volume (68.3% vs. 71.8%; P = 0.8) and rate of achieving ≥50% reduction in volume (81.8% vs. 76.3%; P = 0.68) compared to coils + particles.

CONCLUSIONS

Isolated use of coils for endovascular treatment of cSDHs can be as effective as adjunct use of particle embolization. This method eliminates the risks of cranial nerve and visual complications associated with MMAE, can prevent procedural abortion due to presence of dangerous anastomoses, and reduces the technical complexity of the procedure.

Morphological changes in chronic subdural hematomas following upfront middle meningeal artery embolization: sequence, timing, and association with outcomes

OBJECTIVE

Middle meningeal artery embolization (MMAE) is an increasingly utilized approach for the treatment of chronic subdural hematomas (CSDHs). The course of morphological progression of CSDHs following MMAE is poorly understood. Herein, the authors aimed to describe these morphological changes and assess their prognostic significance for the outcomes on follow-up.

METHODS

A single-institution retrospective cohort study of CSDH cases treated by upfront MMAE, without prior or adjunctive surgical evacuation, was performed. Clinical outcomes, complications, and the need for rescue surgery on follow-up were recorded. Hematomas were categorized into 6 morphological subtypes. All baseline and follow-up head CT scans were assessed for CSDH structural appearance, density, and loculation. Changes in CSDH size were quantified via 3D reconstruction for volumetric measurement.

RESULTS

Overall, 52 CSDHs in 45 patients treated with upfront MMAE were identified. Hematomas were followed for a mean of 92.9 days. Volume decreased by ≥ 50% in 79.6% of the CSDHs. The overall rescue surgery rate was 9.6%. A sequence of morphological changes after MMAE was identified. Hematomas that diverged from this sequence (5.4%) all progressed toward treatment failure and required rescue surgery. The CSDHs were categorized into early, intermediate, and late stages based on the baseline morphological appearance. Progression from early to intermediate and then to late stage took 12.7 and 30.0 days, respectively, on average. The volume of early/intermediate- and late-stage hematomas decreased by ≥ 50%, a mean of 78.2 and 47.6 days after MMAE, respectively. Early- and intermediate-stage hematomas showed a trend toward more favorable outcomes compared with late-stage hematomas. The density of homogeneous hypodense hematomas (HSDHs) transiently increased immediately after MMAE (p < 0.001). A marked decrease in density and volume 1 to 3 weeks after MMAE in HSDHs was detected, the lack of which indicated an eventual need for rescue surgery. In HSDHs, a baseline mean density of < 20 HU, and a lower density than baseline by 1 month post-MMAE were predictors of favorable outcomes. The baseline hematoma volume, axial thickness, midline shift, and loculation were not correlated with MMAE outcomes. Loculated, trabecular, and laminar hematomas, which are known to have unfavorable surgical outcomes, had MMAE outcomes similar to those of other "surgical" hematomas.

CONCLUSIONS

The current study was the first to describe the nature, sequence, and timing of morphological changes of CSDHs after MMAE treatment and has identified structural features that can predict treatment outcomes.

[Middle meningeal artery embolization for chronic subdural haematoma. Case series and literature review]

Middle meningeal artery embolization as primary method for treatment of chronic subdural hematomas became more popular in past decade. There are few large case series (>150 patients) and literature reviews characterizing advantages and drawbacks of endovascular treatment and technical features of surgeries. In this manuscript, the authors report 11 patients with chronic subdural hematoma scheduled for middle meningeal artery embolization and review the literature data on this issue.

Endovascular Treatment of Chronic Subdural Hematomas through Embolization: A Pilot Study with a Non-Adhesive Liquid Embolic Agent of Minimal Viscosity (Squid)

OBJECTIVE

Endovascular embolization using non-adhesive agents (e.g., ethylene vinyl alcohol copolymer with suspended micronized tantalum dissolved in dimethyl sulfoxide; Squid, Balt Extrusion) is an established treatment of brain arteriovenous malformations, dural arteriovenous fistulas, and hypervascular neoplasms. Middle meningeal artery (MMA) embolization is a relatively new concept for treating chronic subdural hematomas (CSDH). This study aimed to evaluate the safety and effectiveness of the use of Squid in the endovascular treatment of CSDH.

METHODS

Embolization was offered to patients with CSDH with minimal or moderate neurological deficits and patients who had previously undergone open surgery to evacuate their CSDH without a significant effect. Distal catheterization of the MMA was followed by embolization of the hematoma capsule with Squid 12 or Squid 18. Safety endpoints were ischemic or hemorrhagic stroke and any other adverse event of the endovascular procedure. Efficacy endpoints were the feasibility of the intended procedure and a ≥ 50% reduction of the maximum depth of the CSDH confirmed by follow-up computed tomography (CT) after >3 months.

RESULTS

Between November 2019 and July 2021, 10 patients (3 female and 7 male, age range 42-89 years) were enrolled. Five patients had bilateral hematomas, and five patients had previously been operated on with no significant effect and recurrent hematoma formation. The attempted embolization was technically possible in all patients. No technical or clinical complication was encountered. During a post-procedural follow-up (median 90 days), 10 patients improved clinically. A complete resolution of the CSDH was observed in 10 patients. The clinical condition of all enrolled patients during the so-far last contact was rated mRS 0 or 1.

CONCLUSION

A distal catheterization of the MMA for the endovascular embolization of CSDH with Squid allowed for the devascularization of the MMA and the dependent vessels of the hematoma capsule. This procedure resulted in a partial or complete resolution of the CSDH. Procedural complications were not encountered.