Middle meningeal artery embolization for chronic subdural hematomas. A systematic review of the literature focused on indications, technical aspects, and future possible perspectives

Newer treatment paradigm improves outcomes in the most common neurosurgical disease of the elderly: a literature review of middle meningeal artery embolization for chronic subdural hematoma

Chronic subdural hematoma (cSDH) is one of the most prevalent neurosurgical diseases, especially in the elderly. Yet, its incidence is predicted to increase further, paralleling the growth of the geriatric population. While surgical evacuation is technically straightforward, it is associated with significant morbidity and mortality. In fact, 30% of patients are expected to have hematoma recurrence and to need repeat surgical evacuation, and 20% of patients are expected to lose independence and require long-term care. A pathophysiology more complex than originally presumed explains the disappointing results observed for decades. At its core, the formation of microcapillaries and anastomotic channels with the middle meningeal artery (MMA) perpetuates a constant cycle resulting in persistence of hematoma. The rationale behind MMA embolization is simple: to stop cSDH at its source. Over the last few years, this "newer" option has been heavily studied. It has shown tremendous potential in decreasing hematoma recurrence and improving neurological outcomes. Whether combined with surgical evacuation or performed as the only treatment, the scientific evidence to its benefits is unequivocal. Here, we aimed to review cSDH in the elderly and discuss its more recent treatment options with an emphasis on MMA embolization.

Updates in traumatic brain injury management: brain oxygenation, middle meningeal artery embolization and new protocols

Traumatic brain injury (TBI) confers significant morbidity and mortality, and is a pathology often encountered by trauma surgeons. Several recent trials have evaluated management protocols of patients with severe TBI. The Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase-II trial (BOOST-II) evaluated efficacy and feasibility of brain oxygen measurement in severe TBI. BOOST phase 3 trial (BOOST-3) and two ongoing trials look to measure functional outcomes in this population. Furthermore, middle meningeal artery embolization has now become standard therapy for adult patients with chronic subdural hematoma (SDH) and has increasing popularity in those with recurrent SDH as an alternative to surgical intervention. In this manuscript, we review the literature, ongoing trials, and discuss current updates in the management of TBI.

Middle meningeal artery patency after surgical evacuation for chronic subdural hematoma

BACKGROUND

Chronic subdural hematoma (CSDH) often requires surgical evacuation, but recurrence rates remain high. Middle meningeal artery (MMA) embolization (MMAE) has been proposed as an alternative or adjunct treatment. There is concern that prior surgery might limit patency, access, penetration, and efficacy of MMAE, such that some recent trials excluded patients with prior craniotomy. However, the impact of prior open surgery on MMA patency has not been studied.

METHODS

A retrospective analysis was conducted on patients who underwent MMAE for cSDH (2019-2022), after prior surgical evacuation or not. MMA patency was assessed using a six-point grading scale.

RESULTS

Of the 109 MMAEs (84 patients, median age 72 years, 20.2% females), 58.7% were upfront MMAEs, while 41.3% were after prior surgery (20 craniotomies, 25 burr holes). Median hematoma thickness was 14 mm and midline shift 3 mm. Hematoma thickness reduction, surgical rescue, and functional outcome did not differ between MMAE subgroups and were not affected by MMA patency or total area of craniotomy or burr-holes. MMA patency was reduced in the craniotomy group only, specifically in the distal portion of the anterior division (p = 0.005), and correlated with craniotomy area (p < 0.001).

CONCLUSION

MMA remains relatively patent after burr-hole evacuation of cSDH, while craniotomy typically only affects the frontal-distal division. However, MMA patency, evacuation method, and total area do not affect outcomes. These findings support the use of MMAE regardless of prior surgery and may influence future trial inclusion/exclusion criteria. Further studies are needed to optimize the timing and techniques for MMAE in cSDH management.

Automated Preoperative and Postoperative Volume Estimates Risk of Retreatment in Chronic Subdural Hematoma: A Retrospective, Multicenter Study

BACKGROUND AND OBJECTIVES

Several neurosurgical pathologies, ranging from glioblastoma to hemorrhagic stroke, use volume thresholds to guide treatment decisions. For chronic subdural hematoma (cSDH), with a risk of retreatment of 10%-30%, the relationship between preoperative and postoperative cSDH volume and retreatment is not well understood. We investigated the potential link between preoperative and postoperative cSDH volumes and retreatment.

METHODS

We performed a retrospective chart review of patients operated for unilateral cSDH from 4 level 1 trauma centers, February 2009-August 2021. We used a 3-dimensional deep learning, automated segmentation pipeline to calculate preoperative and postoperative cSDH volumes. To identify volume thresholds, we constructed a receiver operating curve with preoperative and postoperative volumes to predict cSDH retreatment rates and selected the threshold with the highest Youden index. Then, we developed a light gradient boosting machine to predict the risk of cSDH recurrence.

RESULTS

We identified 538 patients with unilateral cSDH, of whom 62 (12%) underwent surgical retreatment within 6 months of the index surgery. cSDH retreatment was associated with higher preoperative (122 vs 103 mL; P < .001) and postoperative (62 vs 35 mL; P < .001) volumes. Patients with >140 mL preoperative volume had nearly triple the risk of cSDH recurrence compared with those below 140 mL, while a postoperative volume >46 mL led to an increased risk for retreatment (22% vs 6%; P < .001). On multivariate modeling, our model had an area under the receiver operating curve of 0.76 (95% CI: 0.60-0.93) for predicting retreatment. The most important features were preoperative and postoperative volume, platelet count, and age.

CONCLUSION

Larger preoperative and postoperative cSDH volumes increase the risk of retreatment. Volume thresholds may allow identification of patients at high risk of cSDH retreatment who would benefit from adjunct treatments. Machine learning algorithm can quickly provide accurate estimates of preoperative and postoperative volumes.

Middle Meningeal Artery Embolization for Refractory Chronic Subdural Hematoma Associated with Acute Myeloid Leukemia: A Case Report

Objective

We describe a patient with leukemia-related chronic subdural hematoma (CSDH) who was successfully treated using the combination of surgical evacuation and middle meningeal artery (MMA) embolization.

Case Presentation

A 73-year-old man without apparent head trauma history was admitted to our hospital because of acute myeloid leukemia (AML). Head CT on admission revealed mild CSDH on both sides. Medical treatment options, including chemotherapy, were started. Since a decrease in platelet count and disseminated intravascular coagulation were observed on day 4, recombinant thrombomodulin was administered. As the patient exhibited signs of altered consciousness due to the enlargement of the right CSDH on day 10, we performed surgical drainage. Despite subsequent platelet transfusion and administration of goreisan, the right CSDH recurred within a short period. On day 17, we performed the second surgery and MMA embolization in one stage. The postoperative clinical course was favorable without recurrence of the hematoma. The patient eventually died on day 123 from a deterioration of his general condition.

Conclusion

Although MMA embolization has recently been recognized as an effective treatment option for recurrent CSDH, there are no published reports addressing the efficacy of MMA embolization for refractory CSDH associated with hematological malignancies. Findings from the management of this case suggest that MMA embolization can be the effective treatment option for CSDH in patients with severe hemorrhagic diathesis due to AML.

Middle meningeal artery embolization for refractory chronic subdural hematoma in a pediatric victim of nonaccidental trauma: illustrative case

BACKGROUND

Chronic subdural hematoma (cSDH) in children is associated with several etiologies, one of which is nonaccidental trauma (NAT). Performed alone or as an adjunct to surgical intervention, middle meningeal artery (MMA) embolization may be effective in resolving and preventing the recurrence of cSDH in adult patients. However, MMA embolization for pediatric cSDH has not been adequately evaluated, and there exists no consensus on the appropriate selection of pediatric patients for this minimally invasive procedure. Appreciating the variable underlying pathophysiology of pediatric cSDH will enable the development of guidelines for patient selection.

OBSERVATIONS

A 14-month-old female patient presented with depressed consciousness, seizure-like activity, and apneic episodes. She was diagnosed with bilateral subacute on chronic SDH associated with NAT, and imaging revealed diffuse brain atrophy. Despite undergoing burr hole drainage, she developed refractory cSDH and was treated with bilateral MMA embolization. At her 10-month follow-up, magnetic resonance imaging revealed a decrease in the size of the subdural collections, and she was tolerating feeds, at her neurological baseline, and seizure-free.

LESSONS

Infants and young children with symptomatic cSDH secondary to NAT, whose tissue dynamics are reminiscent of cSDH in elderly patients with diffuse brain atrophy, may derive the most benefit from MMA embolization.

Middle meningeal artery embolization for chronic subdural hematoma: a systematic review

Background

Chronic subdural hematoma (cSDH) is one of the most common diseases in neurosurgery. Middle meningeal artery embolization (MMAE) is reportedly an option to prevent recurrence or avoid surgery in patients with cSDH. This study was performed to review the evidence on MMAE for cSDH and evaluate its safety, efficacy, indications, and feasibility.

Methods

We systematically reviewed the literature according to the PRISMA guidelines using an electronic database. The search yielded 43 articles involving 2,783 patients who underwent MMAE.

Results

The hematoma resolution, recurrence, and retreatment rates in the MMAE-alone treatment group (n = 815) were 86.7%, 6.3%, and 9.6%, respectively, whereas those in the prophylactic MMAE with combined surgery group (n = 370) were 95.6%, 4.4%, and 3.4%, respectively. The overall MMAE-related complication rate was 2.3%.

Conclusion

This study shows that MMAE alone is, although not immediate, as effective as evacuation surgery alone in reducing hematoma. The study also shows that combined treatment has a lower recurrence rate than evacuation surgery alone. Because MMAE is a safe procedure, it should be considered for patients with cSDH, especially those with a high risk of recurrence.

Middle Meningeal Artery Embolization for Subdural Hematoma: An Institutional Cohort and Propensity Score-Matched Comparison with Conventional Management

BACKGROUND

The treatment of non-acute subdural hematoma (NASDH) is challenging due to its high recurrence rates and comorbidities of mostly elderly patients. Middle meningeal artery embolization (MMAE) recently emerged as an alternative to surgery in the treatment of NASDH.

OBJECTIVE

To describe a single center's experience of MMAE with Onyx for NASDH and compare it to a surgically treated historical cohort.

METHODS

We performed a retrospective analysis of patients undergoing MMAE for NASDH from 2019 to 2021. MMAE was performed with ethylene vinyl alcohol copolymer (Onyx). Comparisons were made with a historical cohort from 2010 to 2018 who underwent surgical evacuation only, before and after propensity score matching. Outcomes were assessed clinically and radiographically.

RESULTS

We included 44 consecutive patients (55 MMAEs) who underwent MMAE, with a median follow-up of 63.5 days. Twenty-four NASDHs underwent upfront embolization, 17 adjunctive, and 14 for recurrence after prior surgical evacuation, with no significant differences in hematoma and mRS reduction between them. Two patients died during hospitalization and 2 during follow-up, unrelated to the procedure. Mean SDH thickness decreased by 48.3% ± 38.1% (P < 0.001) on last follow-up, which did not correlate with the amount of Onyx injected. Six (13.6%) patients required surgical rescue after embolization. There were no procedure-related complications. The mean modified Rankin Scale (mRS) on admission was 2.8 ± 1.5, which decreased significantly to 1 [1,4] at the last follow-up (P = 0.033). The MMAE (41 hematomas; upfront and adjunctive embolization) and Surgical Evacuation-only (461 hematomas) cohorts were balanced with propensity score mathing. Matching was successful for 41 MMAE and 41 surgical-only hematoma pairs, and only hypertension remained significantly different between the two groups, but there was no significant difference in any outcome.

CONCLUSION

MMAE for NASDH seems safe and effective in appropriately selected patients, non-inferior to surgery, and may become a minimally-invasive alternative. Given our encouraging results, large-scale clinical randomized trials are warranted.

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.

Cost Comparison for Open Surgery versus Middle Meningeal Artery Embolization in Patients with Chronic Subdural Hematomas: A Propensity Score-Matched Analysis

BACKGROUND

Chronic subdural hematoma (cSDH) can be treated with conventional surgery or middle meningeal artery embolization (MMAE). The cost profiles of open surgery versus MMAE have never been studied. Therefore, we sought to compare the costs of surgical and MMAE treatment of cSDH.

METHODS

Patients treated with open surgery (2006-2019) and MMAE (2018-2020) were identified from the institutional database. Propensity score matching analysis was used to assemble a balanced group of subjects. Detailed hospitalization costs in each group were collected and compared.

RESULTS

A total of 341 conventionally treated and 52 MMAE cases were identified. After propensity score matching, 33 patients were included in each group, for a total of 66 patients for analysis. Direct procedural cost was significantly greater in the MMAE group compared with the open surgery group ($38,255 ± $11,859 vs. $11,206 ± $7888; P < 0.001). Medication cost also was greater in the MMAE group ($6888 ± $6525 vs. $4291 ± $3547; P = 0.048). No significant difference was found in costs for intensive care unit care, pharmacy, therapy, laboratory values, and the emergency department. Imaging costs and other miscellaneous costs (e.g., wound care, preoperative, and postanesthesia care unit) were greater in the open surgery group (P < 0.05). Total hospitalization cost was not significantly different between the 2 groups ($60,598 ± 61,315 vs. $71,569 ± $37,813 for open surgery and MMAE respectively, P = 0.385). No significant differences in number of follow ups or total costs for follow up were found (P > 0.05).

CONCLUSIONS

Open surgery and MMAE offer an overall equivalent cost-profile for cSDH treatment when matching for potential cost confounders. Direct procedural costs are greater in MMAE; however, total hospitalization costs and follow up costs are not significantly different.

Middle meningeal artery embolisation: The review of a new treatment for chronic subdural hematomas

Background

This is a literature review aiming to provide an update about the recent findings related to the efficacy of middle meningeal artery embolization (MMAE) in the treatment of chronic subdural hematomas (cSDHs), comparison with conventional therapy and deduction of the current recommendations and indications.

Methods

The literature is reviewed using a search through the PubMed index using keywords. Studies are then screened, skimmed, and thoroughly read. 32 studies fulfilled the inclusion criteria and are included in the study.

Results

Five indications for the application of MMA embolization (MMAE) are deducted from the literature. The usage as a preventive measure after surgical treatment of symptomatic cSDHs in patients with a high risk of recurrence and the usage as a standalone procedure has been the most common reasons for indication of this procedure. Rates of failures for the aforementioned indications have been 6.8% and 3.8%, respectively.

Conclusion

The safety of MMAE as a procedure is regarded as a general theme in the literature and can be considered for future applications. Usage of this procedure in clinical trials with more patient segregation and timeframe assessment relative to surgical intervention are recommendations of this literature review.

Microstructure of embolized capsule of chronic subdural hematoma

Background:

Chronic subdural hematomas (cSDHs) are frequent and potentially life-threatening neurosurgical conditions affecting, first of all, elderly. Few treatment options are available ranging from observation to removal thought large craniotomy. However, currently, there is tendency to minimize surgical aggression, especially considering poor general condition of elderly patients. Thus, one of gaining popularity method of neurointerventional treatment of cSDHs is medial meningeal artery (MMA) embolization. To date, large series of cases published describing favorable outcomes of this treatment approach. At the same time, few reports are available that describe microstructural changes in cSDH’s capsule after embolization; meanwhile, no exact effect of embolization on pathophysiology of hematoma was determined.

Case Description:

Through current paper, we present two cases of cSDH that has previously undergone embolization of MMA, after which cSDHs have been operated through minicraniotomy due to complications after artery embolization. Microstructural changes of hematoma’s capsule are described and discussed.

Conclusion:

Histological changes in embolized capsule suggest embolization of MMA as a valuable method for treatment of cSDHs.

Endoscopically observed outer membrane of chronic subdural hematoma after endovascular embolization of middle meningeal artery

Background:

Embolization of the middle meningeal artery (MMA) has been established for chronic subdural hematoma (CSDH). Neuroendoscopic observation of the outer membrane of the hematoma was carried out after embolization. The treatment mechanism of embolization is discussed, focusing on the vasculature and inflammation of the membrane.

Methods:

Four patients with recurrent CSDH were included in this study. The MMA was embolized using Embosphere® particles in three patients. The outer membrane was observed with normal and narrow band images (NBIs).

Results:

The net-like vessels were not obstructed in the whole area of the outer membrane, but in a patchy fashion of embolized areas surrounded by nonembolized areas. In two patients, the nonembolized areas showed a hemorrhagic inflammatory red color. Histopathological examination confirmed hypertrophic dura with leukocyte infiltration. Dilated dural arteries and proliferated sinusoid arteries were located in the deep and superficial border cell layers. These arteries were visualized as green and brown on NBI, respectively. In the embolized area, the red membrane turned pink, indicating ischemia and subsiding inflammatory hyperemia. In the third patient, the outer membrane was white in both the nonembolized and embolized areas in endoscopic view, and the net-like vessels were sparse in both endoscopy and histology, indicating a scar inflammatory phase. The membrane transition was not observed in the patient that did not undergo embolization.

Conclusion:

Endoscopic observation revealed that embolization of the MMA blocked both the dural and sinusoidal arteries. Ischemic transformation causing the suppression of inflammation of the outer membrane is a suggested mechanism of MMA embolization.

Controversies in the Surgical Treatment of Chronic Subdural Hematoma: A Systematic Scoping Review

Chronic subdural hematoma (cSDH) is one of the most common neurosurgical entities, especially in the elderly population. Diagnosis is usually established via a head computed tomography, while an increasing number of studies are investigating biomarkers to predict the natural history of cSDH, including progression and recurrence. Surgical evacuation remains the mainstay of treatment in the overwhelming majority of cases. Nevertheless, many controversies are associated with the nuances of surgical treatment. We performed a systematic review of the literature between 2010 and 2022, aiming to identify and address the issues in cSDH surgical management where consensus is lacking. The results show ambiguous data in regard to indication, the timing and type of surgery, the duration of drainage, concomitant membranectomy and the need for embolization of the middle meningeal artery. Other aspects of surgical treatment-such as the use of drainage and its location and number of burr holes-seem to have been adequately clarified: the drainage of hematoma is strongly recommended and the outcome is considered as independent of drainage location or the number of burr holes.

Japanese herbal Kampo medicine, Keishibukuryogan, for chronic subdural hematoma – Prospective observational study

Background:

Pharmacological treatment for chronic subdural hematoma (CSDH) recurrence prevention after surgery is under debate. CSDH may be related to suidoku (fluid disturbance) from the Japanese herbal kampo perspective. Goreisan (GRS) treats suidoku and is used to prevent a postoperative recurrence. However, not all CSDHs are liquid, and some have structures such as trabecula, hematoma, and clots, suggesting oketsu (blood stasis). Therefore, we prospectively investigated the keishibukuryogan (KBG) effectiveness, which treats oketsu, for CSDH recurrence prevention and hematoma resolution compared to GRS.

Methods:

We prospectively prescribed KBG 7.5 g/day for 12 CSDH patients after burr-hole surgery. As a control cohort, we retrospectively collected 48 patients treated by GRS 7.5 g/day. The recurrence within 1 month and the hematoma thickness after 1 month were evaluated.

Results:

The median age was 84 years old. All the patients’ symptoms improved after surgery. The median preoperative midline shift and mean hematoma thicknesses were 6.0 mm and 23.75 mm. Those at 1 month were 2.0 mm and 11.43 mm. The recurrence rate was not significantly different between the KBG cohort (1 of 12) and the GRS cohort (4 of 48) (P = 0.999). The KBG’s noninferiority to GRS regarding the hematoma thickness at 1 month was statistically proven; KBG (12.26 mm) and GRS (11.20 mm).

Conclusion:

The recurrence rate at 1 month was not different between the KBG and GRS cohorts. The hematoma thickness at 1 month in the KBG cohort was not statistically inferior to that in the GRS cohort.