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Purpose: Subdural hematoma (SDH) is quickly becoming the most common neurosurgical pathology due to the aging population. Middle meningeal artery embolization (MMAE) has recently emerged as an effective adjunct to surgical SDH evacuation by decreasing recurrence risk. MMAE has also shown promise as a standalone SDH intervention, but clinical and radiographic predictors of successful MMAE remain ill-defined., Methods: Retrospective chart review from 2020 to 2023 at a single center identified all MMAE cases performed as primary SDH treatment. Cases were classified by hematoma internal architecture as homogeneous, separated, laminar, or trabecular. SDH maximal thickness was assessed on all follow-up imaging and any recurrences or expansions requiring surgery were denoted as treatment failures., Results: 164 standalone MMAE cases were reviewed. Most cases were in male patients (75.0%) with a mean age of 73.2 years. The overall MMAE treatment failure rate was 6.7% with a 4.9% periprocedural complication rate. The cases with trabecular and laminar collections were slightly larger than those with homogeneous and separated collections (16.2 mm vs. 14.2 mm, p = 0.008*), but other baseline characteristics were similar. The MMAE failure rate was significantly lower in the laminar and trabecular subgroup (1.2%) compared to the homogeneous and separated subgroup (12.4%) (p = 0.005*). Homogeneous and separated internal hematoma architecture was the only predictor of MMAE failure in multivariate analysis (OR 10.5, p = 0.027*) and was also associated with delayed SDH resorption (ANOVA: F = 4.8, p = 0.0025*)., Conclusions: Standalone MMAE is an effective, safe, and durable treatment for non-acute SDHs, and is especially effective for SDHs with more membranous internal architecture., Competing Interests: Declarations. Ethical approval: This study was approved by the Northwell Feinstein Institute Human Research Protection Program Institutional Review Board: #24–0246 and adheres to the Declaration of Helsinki. Informed consent: As documented in the study protocol approved by our institutional review board and referenced above, informed consent was waived due to the retrospective, non-interventional nature of this study. Competing interests: The authors declare that this research was conducted in the absence of any commercial, financial, or other non-financial relationships that could be construed as a competing interest or a conflict of interest. The authors therefore have no relevant conflicts of interest or competing interests to disclose., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background and Objectives: Middle meningeal artery embolization (MMAE) has emerged as a promising modality for chronic/subacute subdural hematoma treatment; however, consensus regarding embolization technique and embolisate has not been achieved. We thus sought to compare the efficacy of distinct MMAE techniques and embolisate., Methods: An institutional registry was reviewed to identify patients undergoing standalone MMAE for symptomatic chronic/subacute subdural hematoma. Surgical rescue rate and time preceding 50% hematoma resolution were evaluated across 3 technical groups: aggressive penetration (AP), nonaggressive penetration with proximal coil embolization (NP-PC), and nonaggressive penetration alone (NP). Effect sizes were adjusted for demographic, neurological and radiological features through multivariable logistic and Cox regression., Results: Among 117 procedures, 33.3% achieved AP, 36.8% had NP-PC, and 29.9% had NP. The rate of surgical rescue was 2.6% after AP, 9.3% for NP-PC, and 11.4% for NP. In patients not undergoing rescue surgery, 82.4% achieved hematoma resolution ≥50% at a median imaging follow-up of 56 days; AP or NP-PC were each statistically significantly associated with enhanced hematoma resolution as compared with NP ( P = .02). Similarly, sensitivity analysis within medium-size hematoma and antiplatelet/anticoagulation-at-admission subgroups revealed a superiority of resolution after AP or NP-PC. A unique, comparative secondary analysis of liquid embolisate (Onyx vs n-butyl cyanoacrylate) revealed no impact on rate of surgical rescue or hematoma resolution., Conclusion: AP was associated with the lowest rate of surgical rescue, while both AP and NP-PC were associated with improved rates of hematoma resolution., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

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., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Background: Chronic subdural hematoma (SDH) is a particularly challenging pathology due to high recurrence rates (2%-37%) and complex medical comorbidities that tend to afflict the patient population. Recently, there have been several case series published describing the use of middle meningeal artery (MMA) embolization as an alternative to surgery for treatment of new or recurrent chronic SDH., Objective: To describe our first 60 cases of MMA embolization for chronic SDH., Methods: MMA embolization was performed using angiography, selective microcatheterization of the MMA, and infusion of polyvinyl alcohol particles. Outcomes were assessed clinically and with interval imaging studies at 1 d, 2 wk, and 6 wk postprocedure, and additional intervals as indicated., Results: MMA embolization was performed successfully on 60 total SDHs in 49 patients. This includes upfront treatment for new (not previously treated) SDH in 42, for recurrence in 8, and prophylaxis (soon after surgical evacuation) in 10. There were 3 mortalities (unrelated to the procedure), and no procedural complications. Of the 50 nonprophylactic cases, there were 4 (8.9%) cases of recurrence requiring surgical evacuation, and 31 (68.9%) that had resolution or reduction in size >50% of SDH at longest follow-up. Overall, 41 (91.1%) were stable or decreased in size and able to avoid surgery., Conclusion: MMA embolization may represent a minimally-invasive alternative to surgery for new or recurrent chronic SDH, or as prophylaxis to reduce the risk of recurrence after surgery. Given our encouraging results with a 91% long-term success rate, a large scale clinical trial is warranted., (Copyright © 2018 by the Congress of Neurological Surgeons.)

Objective: The purpose of this study was to determine the technical feasibility and safety of middle meningeal arterial (MMA) embolization combined with drilling drainage in the treatment of acute epidural hematoma (AEDH) by comparing it with traditional craniotomy in the treatment., Methods: One hundred seventeen patients with AEDH treated for MMA embolization combined with drilling and drainage or craniotomy hematoma removal from January 2017 to September 2020 were retrospectively analyzed and divided into a craniotomy group (n=85) and a minimally invasive group (n=32). Hematoma removal was performed in the craniotomy group, and MMA embolization combined with drilling and drainage was performed in the minimally invasive group. The general clinical data, imaging data, surgery, and follow-up of the 2 groups were compared and analyzed., Results: Compared with the craniotomy group, the residual hematoma volume in the minimally invasive group was higher than in the craniotomy group. The average postoperative drainage duration in the minimally invasive group was longer than in the craniotomy group. Compared with the craniotomy group, the minimally invasive group was associated with shorter operative time, less intraoperative bleeding, and lower rates of postoperative rebleeding. In addition, the incidence of postoperative complications and length of hospitalization in the minimally invasive group were significantly shortened., Conclusion: Middle meningeal arterial embolization combined with drilling and drainage in the treatment of AEDH caused by MMA active bleeding is safe, effective, and more minimally invasive, and can be promoted and applied., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

Background: Middle meningeal artery (MMA) embolization has recently emerged as a treatment option for chronic subdural hematoma (cSDH). It is considered a simple and potentially safe endovascular procedure., Objective: To compare between 2 different embolic agents; onyx (ethylene vinyl alcohol) and emboparticles (polyvinyl alcohol particles-PVA) for endovascular treatment of cSDH., Methods: A retrospective analysis of all patients who underwent MMA embolization for cSDH treatment in 2 comprehensive centers between August 2018 and December 2021. Primary outcomes were failure of embolization and need for rescue surgical evacuation., Results: Among 97 MMA embolizations, 49 (50.5%) received onyx and 48 (49.5%) received PVA. The presence of acute or subacute on cSDH was higher in the PVA group 11/49 (22.5%) vs 30/48 (62.5%), respectively, P < .001. There were no significant differences between both groups regarding failure of embolization 6/49 (12.2%) vs 12/48 (25.0%), respectively, P = .112, and need of unplanned rescue surgical evacuation 5/49 (10.2%) vs 8/48 (16.7%), respectively, P = .354. Hematoma thickness at late follow-up was significantly smaller in the PVA group 7.8 mm vs 4.6 mm, respectively; P = .017., Conclusion: Both onyx and PVA as embolic agents for cSDH can be used safely and have comparable clinical and surgical outcomes., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Middle meningeal artery embolization (MMAE) for chronic subdural hematomas (cSDHs) has evolved as a potential treatment alternative for these lesions. The indications for using this treatment modality and the pathophysiology of cSDHs are an area of considerable interest. A retrospective review was performed including all major papers addressing this topic. Although considered a relatively new treatment option, MMAE for cSDHs is gaining widespread popularity. There are many questions that need to be addressed regarding its indications, some of which are the subject of ongoing clinical trials. The efficacy of this treatment modality in carefully selected patients has also provided new insights into the potential pathophysiology of cSDHs. This concise review will focus on the current evidence supporting the use of embolization in the treatment of this disease and highlight unanswered relevant clinical questions regarding MMAE indications and technique., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Background: Embolization of the middle meningeal artery (MMA) has recently been proposed as an alternative to surgery for treatment of chronic subdural hematoma (SDH). There is increasing evidence that fragile neovasculature arising from distal branches of the MMA found within the membrane that forms around a chronic SDH is responsible for high recurrence rates due to chronic, repeated rebleeding. Embolization of the MMA could thus potentially eliminate the blood supply to this membrane and prevent further rebleeding., Methods: The cases of 6 patients with 7 recurrent SDHs treated with MMA embolization with polyvinyl alcohol particles were retrospectively reviewed., Results: MMA embolization was performed successfully in all 6 patients with no complications. Of the 7 SDHs treated, 1 required surgical reevacuation due to recurrence. The other 6 were able to avoid surgery, with reduction in size from 12 mm to 11 mm over 3 weeks, 14 mm to 9 mm over 9 weeks, 21 mm to 5 mm over 31 weeks, 17 mm to 9 mm over 12 weeks, 18 mm to 3 mm over 8 weeks, and 25 mm to 6 mm over 24 weeks. All patients had resolution of symptoms at longest follow-up., Conclusions: In this case series of 6 patients harboring 7 recurrent, chronic SDHs, 6 of the 7 were successfully treated with MMA embolization and able to avoid surgery for reevacuation, suggesting that this minimally invasive technique may represent an effective alternative to surgery., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background and purpose Embolization of the middle meningeal artery (MMA) has recently been proposed as an alternative to surgery for treatment of chronic subdural hematoma (SDH), and several case reports have been published supporting its efficacy. It has been suggested that the primary pathologic process in chronic SDH is repeated microhemorrhaging into the subdural collection from fragile neovasculature within the SDH membrane that arises from distal branches of the MMA. Embolization could thus provide a means of eliminating this chronic rebleeding. Materials and methods Images were selected from MMA embolization procedures performed at our institution in order to illustrate the technique and theory behind its efficacy for treatment of chronic SDH. Results Images from MMA angiograms demonstrate the variability of MMA anatomy and help illustrate the importance of avoiding potential ophthalmic collaterals and branches supplying cranial nerves. The findings of irregular wispiness of the distal MMA vasculature, contrast outlining of the SDH membrane on angiography, and homogenous increased density within the SDH on postembolization head computed tomography are described. Conclusion MMA embolization may provide a safe alternative for treatment of chronic SDH, but careful angiographic assessment of MMA anatomy should be performed to avoid potential complications. The findings illustrated here lend support to the theory that the pathologic process of chronic SDH is repeated leakage of blood products from an inflamed, abnormal arterial neovasculature within the SDH membrane that arises from the MMA, and thus selective embolization could provide an effective treatment.

Objective: To explore the clinical feasibility of middle meningeal artery (MMA) embolization combined with endoscopic treatment for new or recurrent chronic subdural hematoma (CSDH)., Methods: Twenty patients with CSDH treated in the Binzhou Medical University Hospital from June 2020 to October 2022 were analyzed retrospectively. The clinical information, prognosis, imaging results, and surgical results of the patients were collected and analyzed. The authors first performed MMA embolization, and then endoscopic treatment of CSDH was performed after successful embolization of MMA. Results: All 20 patients with CSDH were successfully treated with MMA embolization combined with endoscope-assisted evacuation. The symptoms of all patients were relieved, no surgical complications occurred, and no rebleeding and recurrence were found in follow-up computed tomography., Conclusion: Middle meningeal artery embolization combined with endoscopic treatment of CSDH has a good clinical effect, and it may prevent postoperative recurrence., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

The main treatment for chronic subdural hematoma (CSDH) is surgical drilling and drainage. Meanwhile, the most accepted treatment strategy for bilateral CSDHs (bCSDHs) is unilateral evacuation only on the larger or symptomatic side because the contralateral hematoma is generally either small or asymptomatic. However, the probability of recurrence is high. To effectively reduce this recurrence rate, embolization has been proposed. Because middle meningeal artery embolization may effectively block the blood supply of the CSDH, its combination with drilling and drainage could be an effective treatment strategy for addressing unilateral CSDH (uCSDH). In addition, the recurrence mechanism of bCSDH may be not completely same as that of the uCSDH. Hence, the authors need find a more effective treatment for it.

Purpose: Middle meningeal artery (MMA) particle embolization is a promising treatment of chronic subdural hematomas (CSDH). The main purpose of this study is to measure MMA proximal caliber and assess the visibility of the two main MMA branches as a surrogate for long-term distal arterial patency following MMA CSDH embolization with trisacryl gelatine microspheres (TAGM)., Methods: This is a single-center retrospective study. All patients having undergone MMA TAGM only embolization for CSDH treatment between 15 March 2018 and 6 June 2020 with an interpretable follow-up magnetic resonance imaging (MRI) examination and no confounding factors were included. Patients were compared with controls matched for age, sex and MRI machine. Two independent readers analyzed the MRI images., Results: In this study, 30 patients having undergone embolization procedures using TAGM of 36 MMAs were included. The follow-up MRI scans were performed after a mean delay of 14.8 ± 7.1 months (range 4.9-29.4 months). The mean diameter of TAGM embolized MMAs (1 mm; 95% confidence interval, CI 0.9-1.1) was significantly smaller than the mean diameter of paired control MMAs (1.3 mm; 95% CI 1.3-1.4) (p < 0.001). The mean proximal diameter of the embolized MMAs (0.9 mm; 95% CI 0.7-1.1) was significantly smaller than the mean diameter of the contralateral MMAs in the same patients (1.4 mm; 95% CI 1.3-1.6)(p < 0.001)., Conclusion: Long-term follow-up MRI demonstrated a significant impact of TAGM embolization on MMA proximal caliber as well as on the visibility of the two main MMA branches. All comparisons indicated that there was a probable lasting impact of embolization on the patency of distal branches., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Chronic subdural hematoma (cSDH) is defined as a subdural collection of blood on CT imaging that tends to persist and gradually increase in volume over time, with components that are hypodense or isodense compared to the brain. There are no proven guidelines for the management of patients with cSDH. Surgical approaches included burr hole, twist drill hole, and craniotomy-based evacuations. Outcomes after surgical removal is generally favorable, but cSDH tends to recur after the initial evacuation.Middle meningeal artery (MMA) embolization has been gaining increasing popularity among the treatments of cSDH. This is largely due to a growing population of patients with cSDH who are refractory to other treatments or in patients who present with multiple comorbidities or who are taking antiplatelet and anticoagulant medications. The goal of middle meningeal artery (MMA) embolization is to devascularize subdural membranes associated with SDH so that the balance between continued leakage and reabsorption is shifted toward reabsorption.We discuss our clinical and technical approach to cSDH treated with perioperative embolization of the MMA., (© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Background: Middle meningeal artery (MMA) embolization has recently emerged as an effective technique to treat subdural hematomas (SDHs). Studies to date have been limited, largely, to single-center studies with limited follow-up and have not assessed subsequent surgical interventions and factors associated with these interventions., Objective: To evaluate rates of retreatment for SDH after MMA embolization and patient-specific factors that may be important predictors for these interventions., Methods: Using an all-payer claims database, Mariner, patients who underwent MMA embolization between January 2010 and October 2020 after the diagnosis of SDH were identified. Rates of post-MMA embolization surgical interventions, including craniotomy and burr hole drainage, were accessed within 5 years following. Patient-specific contributors to the rates of these interventions were studied using Gaussian logistic regression models., Results: A total of 322 patients were included. Of this cohort, 55 (17.1%) required subsequent intervention within 5 years, with 36 (11.2%) receiving burr hole evacuation and 19 (5.9%) receiving craniotomy. Factor Xa inhibitor use was independently associated with subsequent interventions after MMA embolization procedures (odds ratio: 1.20 [95% CI: 1.02-1.40]). Of the other patient factors evaluated, including age, sex, comorbidity status, and use of vitamin K antagonists, antiplatelets, and factor Xa inhibitors, none were found to be significantly associated with future interventions., Conclusion: Although previous literature has shown MMA embolization to be safe and successful in preventing recurrent SDH, patients undergoing this procedure still carry a risk of future interventions. Patients taking factor Xa inhibitors are at especially high risk of subsequent intervention after MMA embolization., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: Chronic subdural hematomas (CSDHs) are common in the elderly population and patients taking antiplatelet/anticoagulation medications. Middle meningeal artery (MMA) embolization has become an adjunctive treatment to observation and surgery. Despite many embolization techniques, best practices for optimal CSDH resolution remain unknown., Objective: To report a retrospective case series of MMA embolization for CSDHs regarding rate of hematoma improvement and the significance of distal embolic penetration into the falx., Methods: Retrospective chart review was performed on all patients who underwent MMA embolization for CSDHs between January 2017 and June 2021. Patient demographics, clinical presentation, anticoagulant use, and radiographic features were collected. Pre-embolization and postembolization computed tomography scans were analyzed for volumetric changes and assessed for midline penetration of embolic material in the falx., Results: MMA embolization was performed in 37 patients and 53 hemispheres. Older patients took longer to obtain complete resolution of CSDHs (r = 0.47, P = .03). Patients with larger pre-embolization (r = 0.57, P = .007) and postembolization (r = 0.56, P = .008) CSDH volumes took longer to completely resolve. Patients who had n-butyl cyanoacrylate embolization with midline penetration, as evidenced by the "bright falx" sign, had faster improvement rates than those who did not (5.64 cm 3 /d vs 1.2 cm 3 /d, P = .02)., Conclusion: Distal penetration of embolic material, particularly n-butyl cyanoacrylate, into the falx may lead to more rapid improvement of CSDH., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

The treatment of chronic subdural hematoma (cSDH) represents a challenge due to high recurrence rates (2-37%). One possible treatment option is middle meningeal artery (MMA) embolization as an alternative to surgery. In contrast to acute SDH, which is caused by a rupture of the bridging veins, cSDH has a different pathomechanism. Injury to the so-called dural boundary cell layer results in an intermittent or continuous cycle of cell proliferation, angiogenesis, secretion, and bleeding due to rupture of newly formed vessels within the SDH membrane. This membrane is supplied by the MMA. Embolization of the MMA leads to resorption of the cSDH. The results published so far regarding MMA embolization as sole therapy or in combination with surgical treatment are encouraging with a long-term success rate of up to 90%., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Introduction: A common risk factor of chronic, nontraumatic subdural hematoma (SDH) is anticoagulation therapy. Anticoagulation is generally held in patients who develop SDH, but this can lead to thromboembolic events. While prior studies have reported the clinical outcomes of patients with anticoagulation-related SDH, there remains little evidence regarding ongoing anticoagulation treatment., Case Report: We report the management of 2 patients who developed anticoagulation-related SDH and underwent middle meningeal artery (MMA) embolization and successful reinitiation of anticoagulation therapy. In both patients, we conservatively managed anticoagulation with heparin and/or enoxaparin as a bridge to warfarin after MMA embolization. Follow-up computed tomography head revealed interval decrease of SDH and stable neurological status., Conclusions: These cases provide anecdotal evidence of a challenging clinical scenario where there is a necessary indication for therapeutic anticoagulation (ie, venous sinus thrombosis or atrial appendage thrombus) and comorbid SDH. Endovascular MMA embolization may be an effective adjunct therapy for clinical scenarios in patients with SDH and an urgent indication for anticoagulation. Longer follow-up, prospective series, and future randomized clinical trials are needed to objectively assess outcomes in this clinically challenging patient population., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Middle meningeal artery (MMA) embolization has been recognized as a promising treatment for patients with subdural hematoma (SDH)., Objective: To present the technical feasibility and efficacy of n-butyl cyanoacrylate (n-BCA) embolization in the largest consecutive cohort to date., Methods: We retrospectively reviewed our consecutive cases of recurrent SDH treated with MMA embolization using diluted n-BCA with the "sugar rush" technique. In brief, a 2.1-Fr microcatheter was used to selectively catheterize the frontal and posterior branches of the MMA. 5% dextrose in water (D5W) was injected through an intermediate catheter while injecting n-BCA through the microcatheter. Complete obliteration of MMA and lack of SDH recurrence in a 3-6 months follow-up computed tomography scan were defined as efficacy outcomes. Cranial nerve palsy, vision loss, transient neurological deficit, and stroke were defined as safety outcomes., Results: A total of 61 patients were identified with a mean (±standard deviation) age of 62.5 ± 9 years. In 6 patients (10%), coil embolization of the origin of the frontal or posterior branch was performed because super-selective catheterization of the branch was unsuccessful because of tortuous anatomy. Complete obliteration of frontal and posterior branches was achieved in 100% of the cases. Recurrent SDH was seen in 3 patients (5%). No incidence of cranial nerve palsy, vision loss, or stroke occurred. One patient suffered a transient neurological deficit., Conclusion: MMA embolization using diluted n-BCA with concomitant D5W injection is associated with a high degree of distal penetration and complete branch occlusion and minimal risk of cranial nerve palsy or other thromboembolic complications., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Purpose: Middle meningeal artery (MMA) embolization is emerging as a potential treatment of chronic subdural hematomas (CSDHs). The purpose of this study is to describe MMA angiographic anatomy in relation to CSDH embolization., Methods: This retrospective monocentric study was performed on imaging data of MMA embolization procedures for CSDH treatment performed between March 15, 2018 and April 30, 2020. Imaging data, including digital subtraction angiography (DSA) were reviewed independently by two physicians. Discrepancies were resolved by consensus. The MMA bifurcation pattern was analyzed according to an extended Adachi classification. Relations of the MMA with the ophthalmic artery (OA) were also analyzed., Results: In this study, 140 MMAs were analyzed. Dominance of the anterior branch (type I) was observed in only 57/140 (41%) MMAs with a moderate interobserver agreement for classifying MMA into type I against all other (κ = 0.53, 95% confidence interval, CI 0.39-0.67). The posterior branch presented a proximal origin (type A), at the point of emergence of the MMA from the foramen spinosum or its immediate vicinity, in 48/135 (36%) MMAs with a very good interobserver agreement for classifying MMAs into type A against all other (κ = 0.82, 95% CI 0.72-0.92). An angiographic relationship with the OA was observed in 26 MMAs (19%)., Conclusion: In the majority of CSDH patients both anterior and posterior branches of the MMA should be targeted to achieve extensive convexity devascularization. Frequent anatomical variations of the MMA with respect to emergence of the posterior branch and MMA orbital branches are expected to impact CSDH embolization strategy., (© 2021. Springer-Verlag GmbH, DE part of Springer Nature.)

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

Introduction: Refractory or chronic subdural hematomas (cSDH) constitute a challenging entity that neurosurgeons face frequently nowadays. Middle meningeal artery embolization (MMAE) has emerged in the recent years as a promising treatment option. However, solid evidence that can dictate management guidelines is still lacking. Methods: We conducted a systematic review and meta-analysis (MA) in compliance with the PRISMA guidelines to evaluate the efficacy and safety of MMAE compared with conventional treatments for refractory or cSDH. Databases were searched up to March 2019. Using a random-effects model, meta-analyses of proportions and risk difference were conducted recurrence, need for surgical rescue, and complications. Results: Eleven studies (177 patients) were included. Majority (116, 69%) were males with a weighted mean age of 71 + −19.5 years. Meta-analysis of proportions showed treatment failure to be 2.8%, need for surgical rescue 2.7%, and embolization-related complications 1.2%. Meta-analysis of risk-difference between embolized and non-embolized patients showed a 26% (p < 0.001, 95% CI 21%–31%, I2 = 0) lower risk of hematoma recurrence in MMAE. Similarly, in the embolized group, the need for surgical rescue was 20% less (p < 0.001, 95% CI = 12%–27%, I2 = 12.4), and complications were 3.6% less (p = 0.008, 95% CI 1%–6%, I2 = 0) compared to conventional groups. Conclusions: Although MMAE appears to be a promising treatment for refractory or cSDH, drawing definitive conclusions remains limited by paucity of data and small sample sizes. Multicenter, randomized, prospective trials are needed to compare embolization to conventional treatments like watchful waiting, medical management, or surgical evacuation. More extensive research on MMAE could begin a new era in the minimally invasive management of cSDH. [ABSTRACT FROM AUTHOR]