Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: A Review

Operative Neurosurgery 24:469–475, 2023

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.

The Richmond Acute Subdural Hematoma Score: A Validated Grading Scale to Predict Postoperative Mortality

Neurosurgery 90:278–286, 2022

Traumatic acute subdural hematomas (aSDHs) are common, life-threatening injuries often requiring emergency surgery.

OBJECTIVE: To develop and validate the Richmond acute subdural hematoma (RASH) score to stratify patients by risk of mortality after aSDH evacuation.

METHODS: The 2016 National Trauma Data Bank (NTDB) was queried to identify adult patients with traumatic aSDHs who underwent craniectomy or craniotomy within 4 h of arrival to an emergency department. Multivariate logistic regression modeling identified risk factors independently associated with mortality. The RASH score was developed based on a factor’s strength and level of association with mortality. The model was validated using the 2017 NTDB and the area under the receiver operating characteristic curve (AUC).

RESULTS: A total of 2516 cases met study criteria. The patients were 69.3% male with a mean age of 55.7 yr and overall mortality rate of 36.4%. Factors associated with mortality included age between 61 and 79 yr (odds ratio [OR]=2.3, P<.001),age ≥80 yr (OR =6.3, P < .001), loss of consciousness (OR = 2.3, P < .001), Glasgow Coma Scale score of ≤8 (OR = 2.6, P < .001), unilateral (OR = 2.8, P < .001) or bilateral (OR = 3.9, P < .001) unresponsive pupils, and midline shift >5 mm (OR = 1.7, P < .001). Using these risk factors, the RASH score predicted progressively increasing mortality ranging from 0% to 94% for scores of 0 to 8, respectively (AUC = 0.72). Application of the RASH score to 3091 cases from 2017 resulted in similar accuracy (AUC = 0.74).

CONCLUSION: The RASH score is a simple and validated grading scale that uses easily accessible preoperative factors to predict estimated mortality rates in patients with traumatic aSDHs who undergo surgical evacuation.

The trans‑laminar, facet‑joint sparing minimal invasive approach for ventral dural repair in spontaneous intracranial hypotension

Acta Neurochirurgica (2021) 163:3015–3020

We describe the minimally invasive, facet-sparing postero-lateral approach to the thoracic spine for a ventral dural repair in a patient with intracranial hypotension secondary to a spontaneous dural breach.

Methods We performed a minimally invasive approach using a short paramedian posterior skin incision followed by a 10 × 10 mm targeted trans-laminar approach, to achieve a microsurgical repair of a symptomatic ventral dural defect causing severe disability.

Conclusion The facet-sparing postero-lateral approach is safe and effective in the surgical management of thoracic dural tears, even in the most anterior ones, and avoids the traditional costotransversectomy.

Craniectomy size for subdural haematomas and the impact on brain shift and outcomes

Acta Neurochirurgica (2020) 162:2019–2027

Midline shift in trauma relates to the severity of head injury. Large craniectomies are thought to help resolve brain shift but can be associated with higher rates of morbidity. This study explores the relationship between craniectomy size and subtemporal decompression for acute subdural haematomas with the resolution of brain compression and outcomes. No systematic study correlating these measures has been reported.

Method A retrospective study of all adult cases of acute subdural haematomas that presented to a Major Trauma Centre and underwent a primary decompressive craniectomy between June 2008 and August 2013. Data collection included patient demographics and presentation, imaging findings and outcomes. All imaging metrics were measured by two independent trained assessors. Compression was measured as midline shift, brainstem shift and cisternal effacement.

Results Thirty-six patients with mean age of 36.1 ± 12.5 (range 16–62) were included, with a median follow-up of 23.5 months (range 2.2–109.6). The median craniectomy size was 88.7 cm2 and the median subtemporal decompression was 15.0 mm. There was significant post-operative resolution of shift as measured by midline shift, brainstem shift and cisternal effacement score (all p < .00001). There was no mortality, and the majority of patients made a good recovery with 82.8% having a Modified Rankin Score of 2 or less. There was no association between craniectomy size or subtemporal decompression and any markers of brain shift or outcome (all R2 < 0.05).

Conclusions This study suggests that there is no clear relationship between craniectomy size or extent of subtemporal decompression and resolution of brain shift or outcome. Further studies are needed to assess the relative efficacy of large craniectomies and the role of subtemporal decompression.

Development of the Subdural Hematoma in the Elderly (SHE) score to predict mortality

J Neurosurg 132:1616–1622, 2020

The purpose of this study was to describe the development of a novel prognostic score, the Subdural Hematoma in the Elderly (SHE) score. The SHE score is intended to predict 30-day mortality in elderly patients (those > 65 years of age) with an acute, chronic, or mixed-density subdural hematoma (SDH) after minor, or no, prior trauma.

METHODS The authors used the Prognosis Research Strategy group methods to develop the clinical prediction model. The training data set included patients with acute, chronic, and mixed-density SDH. Based on multivariate analyses from a large data set, in addition to review of the extant literature, 3 components to the score were selected: age, admission Glasgow Coma Scale (GCS) score, and SDH volume. Patients are given 1 point if they are over 80 years old, 1 point for an admission GCS score of 5–12, 2 points for an admission GCS score of 3–4, and 1 point for SDH volume > 50 ml. The sum of points across all categories determines the SHE score.

RESULTS The 30-day mortality rate steadily increased as the SHE score increased for all SDH acuities. For patients with an acute SDH, the 30-day mortality rate was 3.2% for SHE score of 0, and the rate increased to 13.1%, 32.7%, 95.7%, and 100% for SHE scores of 1, 2, 3, and 4, respectively. The model was most accurate for acute SDH (area under the curve [AUC] = 0.94), although it still performed well for chronic (AUC = 0.80) and mixed-density (AUC = 0.87) SDH.

CONCLUSIONS The SHE score is a simple clinical grading scale that accurately stratifies patients’ risk of mortality based on age, admission GCS score, and SDH volume. Use of the SHE score could improve counseling of patients and their families, allow for standardization of clinical treatment protocols, and facilitate clinical research studies in SDH.


Subperiosteal versus subdural drainage after burr hole evacuation of chronic subdural hematoma: systematic review and meta-analysis

Acta Neurochirurgica (2020) 162:489–498

The evidence for subperiosteal drainage (SPD) versus subdural drainage (SDD) in chronic subdural hematoma (CSDH) remains controversial, and most surgeons prefer to use SDD over SPD.We aimto assess the latest evidence on the use of SPD compared to SDD in patients with CSDH undergoing burr hole evacuation.

Methods We performed a systematic literature search on topics that assesses the use of SPD compared to SDD in patients with CSDH up until November 2019 from PubMed, EuropePMC, Cochrane Central Database, ScienceDirect, ProQuest, and ClinicalTrials.gov. The primary outcome was recurrent CSDH, and the secondary outcomes were mortality, surgical morbidities, and modified Rankin Score (mRS).

Results There were a total of 3241 subjects from 10 studies. SPD was shown to reduce recurrent CSDH (OR 0.66 [0.52, 0.84], p < 0.001; I2: 17%, p = 0.30) compared to SDD. Recurrent CSDH was lower in SPD group in subgroup analysis at 3-months (OR 0.63 [0.49, 0.81]; I2: 68%, p = 0.04) and 6-months (OR 0.66 [0.51, 0.85], p = 0.001; I2: 77%, p = 0.01) follow-up. However, there was no difference in CSDH recurrence upon subgroup analysis of RCTs. Similar mortality was demonstrated between SPD and SDD group (p = 0.13). The occurrence of parenchymal injury/new neurological deficit was significantly lower in SPD group (OR 0.26 [0.14, 0.51], p < 0.001; I2: 49%, p = 0.08). The rate of seizure, (p = 0.57), postoperative bleeding (p = 0.29), and infection (p = 0.25) were shown to be similar in both SPD and SDD group. Overall, the rate of surgical morbidity was significantly lower in SPD group (OR 0.61 [0.44, 0.85], p = 0.003; I2: 16%, p = 0.25). mRS at the end of follow-up was similar in SPD and SDD group (p = 0.12).

Conclusion SPD was associated with less CSDH recurrence, but similar rate of mortality, seizures, postoperative bleeding, and infections compared to SDD. The rate of parenchymal injury/new neurological deficit was lower in the SPD group.

Middle Meningeal Artery Embolization for Chronic Subdural Hematoma

Neurosurgery, Volume 85, Issue 6, December 2019, Pages 801–807

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 (notpreviously 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.

Smartphone-assisted minimally invasive neurosurgery


J Neurosurg 130:90–98, 2019

Advances in video and fiber optics since the 1990s have led to the development of several commercially available high-definition neuroendoscopes. This technological improvement, however, has been surpassed by the smartphone revolution. With the increasing integration of smartphone technology into medical care, the introduction of these high-quality computerized communication devices with built-in digital cameras offers new possibilities in neuroendoscopy. The aim of this study was to investigate the usefulness of smartphone-endoscope integration in performing different types of minimally invasive neurosurgery.

METHODS The authors present a new surgical tool that integrates a smartphone with an endoscope by use of a specially designed adapter, thus eliminating the need for the video system customarily used for endoscopy. The authors used this novel combined system to perform minimally invasive surgery on patients with various neuropathological disorders, including cavernomas, cerebral aneurysms, hydrocephalus, subdural hematomas, contusional hematomas, and spontaneous intracerebral hematomas.

RESULTS The new endoscopic system featuring smartphone-endoscope integration was used by the authors in the minimally invasive surgical treatment of 42 patients. All procedures were successfully performed, and no complications related to the use of the new method were observed. The quality of the images obtained with the smartphone was high enough to provide adequate information to the neurosurgeons, as smartphone cameras can record images in high definition or 4K resolution. Moreover, because the smartphone screen moves along with the endoscope, surgical mobility was enhanced with the use of this method, facilitating more intuitive use. In fact, this increased mobility was identified as the greatest benefit of the use of the smartphone-endoscope system compared with the use of the neuroendoscope with the standard video set.

CONCLUSIONS Minimally invasive approaches are the new frontier in neurosurgery, and technological innovation and integration are crucial to ongoing progress in the application of these techniques. The use of smartphones with endoscopes is a safe and efficient new method of performing endoscope-assisted neurosurgery that may increase surgeon mobility and reduce equipment costs.  

Aspirin is associated with an increased risk of subdural hematoma in normal-pressure hydrocephalus patients following shunt implantation

Subdural Hematoma

J Neurosurg 123:423–426, 2015

In this paper the authors investigate whether shunt-treated patients with normal-pressure hydrocephalus receiving aspirin therapy are at increased risk of developing subdural hematoma (SDH).

Methods Records from 80 consecutive patients who had undergone implantation of a cerebrospinal fluid shunt for the treatment of normal-pressure hydrocephalus were retrospectively reviewed.

Results Eleven cases of symptomatic SDH occurred, all among patients receiving aspirin or clopidogrel. The 5-year survival estimate was 0.3 (p < 0.0001) for users of aspirin and the hazard ratio was 12.8 (95% CI 3.1–53).

Conclusions Patients on an aspirin therapy regimen have a markedly increased risk of SDH after a shunt has been implanted for the treatment of normal-pressure hydrocephalus. Users of clopidogrel may have an even greater risk.

Traumatic Brain Injuries: The Influence of the Direction of Impact

Traumatic Brain Injuries- The Influence of the Direction of Impact

Neurosurgery 76:81–91, 2015

Head impact direction has been identified as an influential risk factor in the risk of traumatic brain injury (TBI) from animal and anatomic research; however, to date, there has been little investigation into this relationship in human subjects. If a susceptibility to certain types of TBI based on impact direction was found to exist in humans, it would aid in clinical diagnoses as well as prevention methods for these types of injuries.

OBJECTIVE: To examine the influence of impact direction on the presence of TBI lesions, specifically, subdural hematomas, subarachnoid hemorrhage, and parenchymal contusions.

METHODS: Twenty reconstructions of falls that resulted in a TBI were conducted in a laboratory based on eyewitness, interview, and medical reports. The reconstructions involved impacts to a Hybrid III anthropometric dummy and finite element modeling of the human head to evaluate the brain stresses and strains for each TBI event.

RESULTS: The results showed that it is likely that increased risk of incurring a subdural hematoma exists from impacts to the frontal or occipital regions, and parenchymal contusions from impacts to the side of the head. There was no definitive link between impact direction and subarachnoid hemorrhage. In addition, the results indicate that there is a continuum of stresses and strain magnitudes between lesion types when impact location is isolated, with subdural hematoma occurring at lower magnitudes for frontal and occipital region impacts, and contusions lower for impacts to the side.

CONCLUSION: This hospital data set suggests that there is an effect that impact direction has on TBI depending on the anatomy involved for each particular lesion.

Intracranial hypotension producing reversible coma

J Neurosurg 117:615–628, 2012

Intracranial hypotension is a disorder of CSF hypovolemia due to iatrogenic or spontaneous spinal CSF leakage. Rarely, positional headaches may progress to coma, with frequent misdiagnosis. The authors review reported cases of verified intracranial hypotension–associated coma, including 3 previously unpublished cases, totaling 29. Most patients presented with headache prior to neurological deterioration, with positional symptoms elicited in almost half. Eight patients had recently undergone a spinal procedure such as lumbar drainage. Diagnostic workup almost always began with a head CT scan. Subdural collections were present in 86%; however, intracranial hypotension was frequently unrecognized as the underlying cause. Twelve patients underwent one or more procedures to evacuate the collections, sometimes with transiently improved mental status. However, no patient experienced lasting neurological improvement after subdural fluid evacuation alone, and some deteriorated further. Intracranial hypotension was diagnosed in most patients via MRI studies, which were often obtained due to failure to improve after subdural hematoma (SDH) evacuation. Once the diagnosis of intracranial hypotension was made, placement of epidural blood patches was curative in 85% of patients. Twenty-seven patients (93%) experienced favorable outcomes after diagnosis and treatment; 1 patient died, and 1 patient had a morbid outcome secondary to duret hemorrhages. The literature review revealed that numerous additional patients with clinical histories consistent with intracranial hypotension but no radiological confirmation developed SDH following a spinal procedure. Several such patients experienced poor outcomes, and there were multiple deaths. To facilitate recognition of this treatable but potentially life-threatening condition, the authors propose criteria that should prompt intracranial hypotension workup in the comatose patient and present a stepwise management algorithm to guide the appropriate diagnosis and treatment of these patients.


Subdural Hematoma in Patients With Cancer

Neurosurgery 71:74–79, 2012 DOI: 10.1227/NEU.0b013e3182517938

Subdural hematoma (SDH) in patients with cancer is poorly described, and its frequency and causes may have changed with recent oncologic advances.

OBJECTIVE: We conducted an analysis of the clinical and radiographic features, etiologies, treatments, and outcomes of patients with SDHs and cancer.

METHODS: We retrospectively identified patients at Memorial Sloan-Kettering Cancer Center with a diagnosis of SDH and cancer from January 2000 to December 2007. We analyzed clinical and radiographic data; multivariate Cox regression was performed to associate tumor type and etiology with survival outcome.

RESULTS: There were 90 patients; 66 had acute or subacute SDHs, 9 chronic SDHs, 11 subdural hygromas, and 4 SDHs of unclear chronicity. Gliomas (16%), leukemias (14%), and prostate cancers (14%) were the most frequent malignancies. The most common single etiologies were coagulopathy (27%) and trauma (11%). SDHs with multiple etiologies occurred in 25 patients (28%) with the combination of coagulopathy and trauma occurring in 15. Sixty patients (67%) were either completely or partially independent after SDH, and 1-year survival was 43% (95% confidence interval: 32.1-52.9). Overall survival correlated with etiology (P , .0001) and whether the malignancy was in remission (P = .005). Trauma was associated with the best overall survival compared with coagulopathy.

CONCLUSION: Leukemia and prostate cancer are the most common systemic cancers associated with SDH, and gliomas may predispose to SDH more often than previously recognized. Coagulopathy is common and associated with the worst outcome, but many patients experience good functional outcome and survival.

The surgical management of chronic subdural hematoma

Neurosurg Rev DOI 10.1007/s10143-011-0349-y

Chronic subdural hematoma (cSDH) is an increasingly common neurological disease process. Despite the wide prevalence of cSDH, there remains a lack of consensus regarding numerous aspects of its clinical management. We provide an overview of the epidemiology and pathophysiology of cSDH and discuss several controversial management issues, including the timing of postoperative resumption of anticoagulant medications, the effectiveness of anti-epileptic prophylaxis, protocols for mobilization following evacuation of cSDH, as well as the comparative effectiveness of the various techniques of surgical evacuation.

A PubMed search was carried out through October 19, 2010 using the following keywords: “subdural hematoma”, “craniotomy”, “burr-hole”, “management”, “anticoagulation”, “seizure prophylaxis”, “antiplatelet”, “mobilization”, and “surgical evacuation”, alone and in combination. Relevant articles were identified and back-referenced to yield additional papers. A meta-analysis was then performed comparing the efficacy and complications associated with the various methods of cSDH evacuation.

There is general agreement that significant coagulopathy should be reversed expeditiously in patients presenting with cSDH. Although protocols for gradual resumption of anti-coagulation for prophylaxis of venous thrombosis may be derived from guidelines for other neurosurgical procedures, further prospective study is necessary to determine the optimal time to restart fulldose anti-coagulation in the setting of recently drained cSDH. There is also conflicting evidence to support seizure prophylaxis in patients with cSDH, although the existing literature supports prophylaxis in patients who are at a higher risk for seizures.

The published data regarding surgical technique for cSDH supports primary twist drill craniostomy (TDC) drainage at the bedside for patients who are high-risk surgical candidates with non-septated cSDH and craniotomy as a first-line evacuation technique for cSDH with significant membranes. Larger prospective studies addressing these aspects of cSDH management are necessary to establish definitive recommendations.

Arachnoid cysts of the middle cranial fossa accompanied by subdural effusions—experience with 60 consecutive cases

Acta Neurochir (2011) 153:75–84 DOI 10.1007/s00701-010-0820-5

Subdural effusions (SDEs) can complicate arachnoid cysts of the middle cranial fossa (ACMFs). While there is a consensus that at least in adults asymptomatic ACMFs should not be operated, those with concomitant subdural and/or intracystic effusions are clinically apparent in the majority of cases and should be surgically treated. But it remains unclear, which surgical procedure is best.

Methods Since 1980, 60 out of 343 patients with an ACMF presented with accompanying SDEs. Four categories of SDEs were differentiated radiologically. This collective was controlled in a follow-up study up to 60 months after con- servative or operative treatment by clinical and radiological means.

Results In 54 of the 60 patients, we saw an indication for surgical treatment. Twenty-nine patients received a burr hole, 13 cases were treated by craniotomy, seven by endoscopical means, three patients underwent shunting and two combined procedures. Six patients were treated conservatively. An excellent final clinical outcome was observed in 55 cases. While craniotomy succeeded best to reduce the cyst volume in postoperative CT, the final clinical outcome did not differ significantly compared with burr hole trepanation.

Conclusions Patients with small effusions can be treated conservatively in selected cases. Based on our experience, we prefer a differentiated therapy. As first procedure, burr hole and subdural drainage were performed, leaving the cyst alone, seeming sufficient for the majority of cases. Craniotomy or endoscopical means should be reserved as treatment of choice for special cases, depending on category and acuteness of SDE and size/localisation of the ACMF.

The major complications of transpedicular vertebroplasty

J Neurosurg Spine 11:607–613, 2009. DOI: 10.3171/2009.4.SPINE08466

Vertebroplasty is a well-known technique used to treat pain associated with vertebral. Despite a success rate of up to 90% in different series, the procedure is often associated such as cord and root compression, epidural and subdural hematomas (SDHs), and other minor complications. In this study, the authors discuss the major complications of and their clinical implications during the postoperative course.

Methods. Vertebroplasty was performed in 12 vertebrae of 7 patients. Five patients had fractures, 1 had tumoral compression fractures, and 1 had a traumatic fracture. Two leakage, 1 had epidural leakage, 1 had subdural cement leakage, 2 had a spinal SDH, and after the procedure.

Results. Three patients had paraparesis (2 had SDHs and 1 had epidural cement leakage), 3 had root symptoms, and 1 had lower back pain. Two of the 3 patients with paraparesis recovered after evacuation of the SDH and subdural cement; however, 1 patient with paraparesis did not recover after epidural cement leakage, despite cement evacuation. Two patients with foraminal leakage and 1 with subdural cement leakage had root symptoms and recovered after evacuation and conservative treatment. The patient with the split fracture had no neurological symptoms and recovered with conservative treatment.

Conclusions. Transpedicular vertebroplasty may have major complications, such as a spinal SDH and/or cement leakage into the epidural and subdural spaces, even when performed by experienced spinal surgeons. Early diagnosis with CT and intervention may prevent worsening of these complications.

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