Letter to editor : Local anesthesia with sedation and general anesthesia for the treatment of chronic subdural hematoma: a systematic review and meta­analysis of published cases.

This critique evaluates the systematic review and meta-analysis titled "Local anesthesia with sedation and general anesthesia for the treatment of chronic subdural hematoma." The study provides valuable insights into anesthesia techniques' effectiveness in managing this condition but has limitations, including selection bias, heterogeneity among cases, lack of standardized protocols, and retrospective design. Despite these limitations, the review contributes to understanding chronic subdural hematoma management but underscores the need for future research to address these shortcomings.

Challenges and patient outcomes in chronic subdural haematoma at the level of a regional care system A multi-centre, mixed-methods study from the East of England.

BACKGROUND: Chronic subdural haematoma (cSDH) is a common neurosurgical pathology affecting older patients with other health conditions. A significant proportion (up-to 90%) of referrals for surgery in neurosciences units (NSU) come from secondary care. However, the organisation of this care and the experience of patients repatriated to non-specialist centres are currently unclear. OBJECTIVES: This study aimed to clarify patient outcome in non-specialist centres following NSU discharge for cSDH surgery and to understand key system challenges. The study was set within a representative neurosurgical care system in the east of England. DESIGN AND METHODS: We performed a retrospective cohort analysis of patients referred for cSDH surgery. Alongside case record review, patient and staff experience were explored using surveys as well as an interactive c-design workshop. Challenges were identified from thematic analysis of survey responses and triangulated by focussed workshop discussions. RESULTS: Data on 381 patients referred for cSDH surgery from six centres was reviewed. One hundred and fifty-six (41%) patients were repatriated following surgery. Sixty-one (39%) of those repatriated suffered an inpatient complication (new infection, troponin rise or renal injury) following NSU discharge, with 58 requiring institutional discharge or new care. Surveys for staff (n = 42) and patients (n = 209) identified that resourcing, communication, and inter-hospital distance posed care challenges. This was corroborated through workshop discussions with stakeholders from two institutions. CONCLUSIONS: A significant amount of perioperative care for cSDH is delivered outside of specialist centres. Future improvement initiatives must recognise the system-wide nature of delivery and the challenges such an arrangement presents.

"Curtain-fall" technique for cerebrospinal fluid leak prevention after removal of intradural drainage. Technical note: application in chronic subdural hematoma surgery.

OBJECTIVE: Chronic subdural hematoma (CSDH) is frequently met in neurosurgical practice and often need urgent surgical treatment in case of neurological deterioration. Different surgical approaches to evacuate CSDH are described in the literature. In our experience, an external drainage system is crucial in order to avoid recurrences. We recently encountered a case of subcutaneous CSF collection after drainage removal. Thus, we developed a simple surgical technique to prevent postoperative CSF leak after subdural drainage system removal. METHOD: We have developed a technique in which the periosteum is harvested during the surgery prior to the evacuation of the hemorrhage and fixed with sutures on the uncut dura mater opposite and laterally to the exit of the catheter exiting the dural hole caused by the passage of the Jackson-Pratt subdural drainage system. When the drainage catheter is removed, the flap, partially held by the sutures, falls over the hole avoiding CSF leakage. By using this technique, the small dural hole will be covered with the periosteum allowing for natural closure and wound healing hence preventing CSF leakage. RESULTS: This technique was successfully employed in 21 patients who didn't develop postoperative CSF leakage following CSDH evacuation and removal of subdural drainage system. CONCLUSION: In this technical note, we describe a safe dura closure technique that we developed to help reduce the risk of postoperative CSF leakage following subdural drainage removal, which can, however, also be applied in all surgeries in which a catheter is placed in the subdural space.

Local anesthesia with sedation and general anesthesia for the treatment of chronic subdural hematoma: a systematic review and meta-analysis.

BACKGROUND: Surgery is the primary treatment for chronic subdural hematoma, and anesthesia significantly impacts the surgery's outcomes. A previous systematic review compared general anesthesia to local anesthesia in 319 patients. Our study builds upon this research, analyzing 4,367 cases to provide updated and rigorous evidence. METHODS: We systematically searched five electronic databases: PubMed, Cochrane Library, Scopus, Ovid Medline, and Web of Science, to identify eligible comparative studies. All studies published until September 2023 were included in our analysis. We compared six primary outcomes between the two groups using Review Manager Software. RESULTS: Eighteen studies involving a total of 4,367 participants were included in the meta-analysis. The analysis revealed no significant difference between the two techniques in terms of 'recurrence rate' (OR = 0.95, 95% CI [0.78 to 1.15], P = 0.59), 'mortality rate' (OR = 1.02, 95% CI [0.55 to 1.88], P = 0.96), and 'reoperation rate' (OR = 0.95, 95% CI [0.5 to 1.79], P = 0.87). Local anesthesia demonstrated superiority with a lower 'complications rate' than general anesthesia, as the latter had almost 2.4 times higher odds of experiencing complications (OR = 2.4, 95% CI [1.81 to 3.17], P < 0.00001). Additionally, local anesthesia was associated with a shorter 'length of hospital stay' (SMD = 1.19, 95% CI [1.06 to 1.32], P < 0.00001) and a reduced 'duration of surgery' (SMD = 0.94, 95% CI [0.67 to 1.2], P < 0.00001). CONCLUSION: Surgery for chronic subdural hematoma under local anesthesia results in fewer complications, a shorter length of hospital stay, and a shorter duration of the operation.

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.

Irrigation versus no irrigation in the treatment of chronic subdural hematoma: An updated systematic review and meta-analysis of 1581 patients.

Burr hole craniotomy is a common technique employed in the treatment of chronic subdural hematoma. However, its effectiveness and the occurrence of additional complications with various irrigation techniques utilized during the surgery remain unclear. The paper aims to compare the effectiveness and safety of burr hole craniotomy with and without irrigation in the treatment of chronic subdural hematoma. We conducted a systematic review by searching PubMed, Cochrane Library, Scopus, Ovid, and Web of Science for comparative studies that fit the eligibility criteria. All studies up to January 2023 were included, and the two groups were compared based on five primary outcomes using Review Manager Software. Data reported as odds ratio (OR) or risk ratio (RR) and 95% confidence interval (CI). A p-value of less than 0.05 was considered statistically significant. Our analysis included 12 studies with a total of 1581 patients. There was no significant difference between the two techniques in terms of recurrence rate (OR = 0.94; 95% CI [0.55, 1.06], p-value = 0.81) and mortality rate (RR = 1.05, 95% CI [0.46, 2.40], p-value = 0.91). Similarly, there was no significant difference in postoperative infection (RR = 1.15, 95% CI [0.16, 8.05], p-value = 0.89) or postoperative pneumocephalus (RR = 2.56, 95% CI [0.95, 6.89], p-value = 0.06). The burr hole drainage with irrigation technique was insignificantly associated with a higher risk of postoperative hemorrhagic complication (RR = 2.23, 95% CI [0.94, 5.29], p-value = 0.07); however, sensitivity analysis showed significant association based on the results of two studies (RR = 4.6, 95% CI [1.23, 17.25], p-value = 0.024). The two techniques showed comparable recurrence, mortality rate, postoperative infection, and postoperative pneumocephalus results. However, irrigation in burr hole craniotomy could possibly have a higher risk of postoperative hemorrhage compared with no irrigation, as observed during sensitivity analysis, which requires to be confirmed by other studies. Further research and randomized controlled trials are required to understand these observations better and their applicability in clinical practice.

Incidence of surgically treated chronic subdural hematoma after head injury with normal initial computed tomography.

PURPOSE: The objective was to determine the incidence of surgically treated chronic subdural hematoma (cSDH) within six months after head trauma in a consecutive series of head injury patients with a normal initial computed tomography (CT). METHODS: A total of 1941 adult patients with head injuries who underwent head CT within 48 h after injury and were treated at the Tampere University Hospital's emergency department were retrospectively evaluated from medical records (median age = 59 years, IQR = 39-79 years, males = 58%, patients using antithrombotic medication = 26%). Patients with no signs of acute traumatic intracranial pathology or any type of subdural collection on initial head CT were regarded as CT negative (n = 1573, 81%). RESULTS: Two (n = 2) of the 1573 CT negative patients received surgical treatment for cSDH. Consequently, the incidence of surgically treated cSDH after a normal initial head CT during a six-month follow-up was 0.13%. Both patients sustained mild traumatic brain injuries initially. One of the two patients was on antithrombotic medication (warfarin) at the time of trauma, hence incidence of surgically treated cSDH among patients with antithrombotic medication in CT negative patients (n = 376, 23.9%) was 0.27%. Additionally, within CT negative patients, one subdural hygroma was operated shortly after trauma. CONCLUSION: The extremely low incidence of surgically treated cSDH after a normal initial head CT, even in patients on antithrombotic medication, supports the notion that routine follow-up imaging after an initial normal head CT is not indicated to exclude the development of cSDH. Additionally, our findings support the concept of cSDH not being a purely head trauma-related disease.

Are there characteristic indicators for increased pressure in chronic subdural hematoma?

Chronic subdural hematoma (CSDH) is one of the most common neurosurgical disorders. However, no study has yet documented biomarkers indicating increased CSDH pressure. This study aimed to explore such indicators. A total of 50 patients underwent measurement for CSDH pressure during burr-hole irrigation. The mean hematoma pressure was 16.8 ± 7.6 cmH2O with no significant difference between new-onset and recurrent CSDHs. In 12 patients with a CSDH pressure ≥25 cmH2O, further analyses were carried out. Eight of them had bilateral CSDHs. All six patients with a CSDH pressure ≥28 cmH2O suffered headaches before surgery. Two out of three patients with a CSDH pressure ≥29 cmH2O felt nauseous. In statistical analyses, headache was positively correlated with a high CSDH pressure, whereas age and hematoma thickness were negatively correlated with it. Patients' sex, initial Glasgow coma scale score, motor weakness, midline shift on computed tomography scans, and administration of anticoagulants/antiplatelet agents, showed no significant correlation. When patients with bilateral CSDHs are not older adults and suffering headaches, an increased CSDH pressure should be assumed. For such patients, a prompt hematoma evacuation is indicated.

Passive or active drainage system for chronic subdural haematoma-a single-center retrospective follow-up study.

BACKGROUND: Postoperative drainage systems have become a standard treatment for chronic subdural hematoma (CSDH). We previously compared treatment results from three Scandinavian centers using three different postoperative drainage systems and concluded that the active subgaleal drainage was associated with lower recurrence and complication rates than the passive subdural drainage. We consequently changed clinical practice from using the passive subdural drainage to the active subgaleal drainage. OBJECTIVE: The aim of the present study was to assess a potential change in reoperation rates for CSDH after conversion to the active subgaleal drainage. METHODS: This single-center cohort study compared the reoperation rates for recurrent same-sided CSDH and postoperative complication rates between patients treated during two study periods (passive subdural drainage cohort versus active subgaleal drainage cohort). RESULTS: In total, 594 patients were included in the study. We found no significant difference in reoperation rates between the passive subdural drain group and the active subgaleal drain group (21.6%, 95% CI 17.5-26.4% vs. 18.0%, 95% CI 13.8-23.2%; p = 0.275). There was no statistical difference in the rate of serious complications between the groups. The operating time was significantly shorter for patients operated with the active subgaleal drain than patients with the passive subdural drain (32.8 min, 95% CI 31.2-34.5 min vs. 47.6 min, 95% CI 44.7-50.4 min; p < 0.001). CONCLUSIONS: Conversion from the passive subdural to the active subgaleal drainage did not result in a clear reduction of reoperation rates for CSDH in our center.

Efficacy and safety of bedside percutaneous three-millimeter twist-drill trephination under local anesthesia-a retrospective study of 1000 patients.

PURPOSE: Percutaneous 3-mm twist-drill trephination (TDT) under local anesthesia as a bedside operative technique is an alternative to the conventional open surgical trephination in the operating theatre. The aim of this study was to verify the efficacy and safety of this minimal invasive procedure. METHODS: This retrospective study comprises 1000 patients who were treated with TDT under local anesthesia at bedside due to chronic subdural hematoma (cSDH), intracerebral hemorrhage (ICH), and hydrocephalus (HYD) as a result of subarachnoid hemorrhage or non-hemorrhagic causes, increased intracranial pressure (IIP) in traumatic brain injury or non-traumatic brain edema, and other pathologies (OP) requiring drainage. Medical records, clinical outcome, and results of pre- and postoperative computed tomography (CT) and/or magnetic resonance tomography (MRT) were analyzed. RESULTS: Indications for TDT were cSDH (n = 275; 27.5%), ICH (n = 291; 29.1%), HYD (n = 316; 31.6%), IIP (n = 112; 11.2%), and OP (n = 6; 0.6%). Overall, primary catheter placement was sufficient in 93.8% of trephinations. Complication rate was 14.1% and mainly related to primary catheter malposition (6.2%), infections (5.2%), and secondary hemorrhage (2.7%); the majority of which were clinically inapparent puncture channel bleedings not requiring surgical intervention. The revision rate was 13%. CONCLUSIONS: Bedside TDT under local anesthesia has proven to be an effective and safe alternative to the conventional burr-hole operative technique as usually performed under general anesthesia in the operation theatre, and may be particularly useful in emergency cases as well as in elderly and multimorbid patients.

Granuloma formation as a late complication of burr-hole surgery for chronic subdural hematoma.

BACKGROUND: Surgical treatment remains the mainstream therapeutic regimen for chronic subdural hematoma (CSDH), and burr-hole craniostomy with subdural drainage is the preferable approach. Herein, we reported a case of intracranial granuloma formation as a late complication of burr-hole surgery for CSDH. CASE PRESENTATION: A 31-year-old man presented with a 1-month history of headache. Head computed tomography (CT) showed a subdural hematoma in the left frontal-temporal-parietal region with significant midline shifting. A burr-hole evacuation of the hematoma with closed-system drainage was performed. CT obtained immediately after the surgery demonstrated that the hematoma was mostly evacuated. Nine months later, he presented to us again due to intermittent headache in the left temporoparietal region. Brain magnetic resonance imaging revealed a space-occupying mass at the site of the original hematoma. A bone-flap craniotomy was performed for resecting the mass. Histopathological examination revealed a granuloma. The microbial cultivation of the resected specimen was negative. The postoperative course was uneventful, and the headache was relieved. CONCLUSION: Granuloma formation is an extremely rare late complication of burr-hole surgery for CSDH. Physicians involved in the perioperative management of CSDH should be aware of this condition, and bone-flap craniotomy may be warranted.

Chronic Subdural Hematoma Drainage under Local versus General Anesthesia: Systematic Review and Meta-Analysis.

BACKGROUND: Chronic subdural hematoma (CSDH) is one of the most frequently encountered neurosurgical conditions. Although the mainstay treatment of chronic subdural hematoma has been burr-hole drainage, no consensus yet exists on the optimal anesthetic strategy between general anesthesia (GA) and local anesthesia (LA). This systematic review compares postoperative outcomes after CSDH evacuation under LA and GA. METHODS: A search was conducted in MEDLINE (1946 to November 2023), Embase (1974 to November 2023), and PubMed (up to November 2023). We followed the PRISMA guidelines to systematically screen studies. RESULTS: Our literature search identified 629 studies, out of which 12 were included. There were 1035 patients in the LA group and 699 patients in the GA group. Our meta-analysis found that the LA group had significantly shorter operative time (mean difference, -29.28 minutes; P < 0.0001), length of admission (mean difference, -1.58 days; 95% confidence interval [CI], -2.40 to -0.76 days; P = 0.0002), and postoperative complications rate (odds ratio [OR], 0.38; 95% CI, 0.25-0.59; P < 0.0001) compared with GA. There was no significant difference between the 2 groups in revision rate (OR, 0.77; 95% CI, 0.39-1.51; P = 0.45) and mortality (OR, 1.23; 95% CI, 0.63-2.43; P = 0.55). CONCLUSIONS: In this meta-analysis, LA shows benefits in shorter operative time, shorter admission length, and fewer postoperative complications. This finding makes LA a less invasive alternative to GA, especially in elderly patients.

Efficacy of intraoperative irrigation with artificial cerebrospinal fluid in chronic subdural hematoma surgery: study protocol for a multicenter randomized controlled trial.

BACKGROUND: The surgical techniques for treatment of chronic subdural hematoma (CSDH), a common neurosurgical condition, have been discussed in a lot of clinical literature. However, the recurrence proportion after CSDH surgery remains high, ranging from 10 to 20%. The standard surgical procedure for CSDH involves a craniostomy to evacuate the hematoma, but irrigating the hematoma cavity during the procedure is debatable. The authors hypothesized that the choice of irrigation fluid might be a key factor affecting the outcomes of surgery. This multicenter randomized controlled trial aims to investigate whether intraoperative irrigation using artificial cerebrospinal fluid (ACF) followed by the placement of a subdural drain would yield superior results compared to the placement of a subdural drain alone for CSDH. METHODS: The study will be conducted across 19 neurosurgical departments in Japan. The 1186 eligible patients will be randomly allocated to two groups: irrigation using ACF or not. In either group, a subdural drain is to be placed for at least 12 h postoperatively. Similar to what was done in previous studies, we set the proportion of patients that meet the criteria for ipsilateral reoperation at 7% in the irrigation group and 12% in the non-irrigation group. The primary endpoint is the proportion of patients who meet the criteria for ipsilateral reoperation within 6 months of surgery (clinical worsening of symptoms and increased hematoma on imaging compared with the postoperative state). The secondary endpoints are the proportion of reoperations within 6 months, the proportion being stratified by preoperative hematoma architecture by computed tomography (CT) scan, neurological symptoms, patient condition, mortality at 6 months, complications associated with surgery, length of hospital stay from surgery to discharge, and time of the surgical procedure. DISCUSSION: We present the study protocol for a multicenter randomized controlled trial to investigate our hypothesis that intraoperative irrigation with ACF reduces the recurrence proportion after the removal of chronic subdural hematomas compared with no irrigation. TRIAL REGISTRATION: ClinicalTrials.gov jRCT1041220124. Registered on January 13, 2023.

LC-MS-based urine metabolomics analysis of chronic subdural hematoma for biomarker discovery.

BACKGROUND: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical diseases with atypical manifestations. The aim of this study was to utilize urine metabolomics to explore potential biomarkers for the diagnosis and prognosis of CSDH. METHODS: Seventy-seven healthy controls and ninety-two patients with CSDH were enrolled in our study. In total, 261 urine samples divided into the discovery group and validation group were analyzed by LC-MS. The statistical analysis and functional annotation were applied to discover potential biomarker panels and altered metabolic pathways. RESULTS: A total of 53 differential metabolites were identified in this study. And the urinary metabolic profiles showed apparent separation between patients and controls. Further functional annotation showed that the differential metabolites were associated with lipid metabolism, fatty acid metabolism, amino acid metabolism, biotin metabolism, steroid hormone biosynthesis, and pentose and glucuronate interconversions. Moreover, one panel of Capryloylglycine, cis-5-Octenoic acid, Ethisterone, and 5,6-DiHETE showed good predictive performance in the diagnosis of CSDH, with an AUC of 0.89 in discovery group and an AUC of 0.822 in validation group. Another five metabolites (Trilobinol, 3'-Hydroxyropivacaine, Ethisterone, Arginyl-Proline, 5-alpha-Dihydrotestosterone glucuronide) showed the levels of them returned to a healthy state after surgery, showing good possibility to monitor the recovery of CSDH patients. CONCLUSION AND CLINICAL RELEVANCE: The findings of the study revealed urine metabolomic differences between CSDH and controls. The potentially diagnostic and prognostic biomarker panels of urine metabolites were established, and functional analysis demonstrated deeper metabolic disorders of CSDH, which might conduce to improve early diagnose of CSDH clinically.

Neuroendoscopic Technique for Septated Chronic Subdural Hematoma: A Retrospective Study.

OBJECTIVES: To compare the efficacy of neuroendoscopic hematoma evacuation (NHE) and burr hole craniotomy (BHC) for treating septated chronic subdural hematoma (sCSDH) and analyze the technical advantages of NHE in sCSDH treatment by data analysis. METHODS: This study recruited 77 patients with sCSDH According to the type of operation, the patients were divided into NHE (n = 45) or BHC (n = 32) groups. Clinical data were retrospectively analyzed to evaluate and compare the efficacy of NHE and BHC for treating sCSDH. RESULTS: NHE demonstrated higher complete hematoma clearance and postoperative midline recovery rates and shorter subdural drainage and postoperative bed rest durations compared with BHC (P < 0.05). The average NHE time (72.27 ± 18.27 minutes) was longer than that of BHC (54.91 ± 16.04 minutes) (P < 0.05). The average follow-up period was 30.9 (range, 7-51) months. The results revealed that 1 and 12 cases recurred in the NHE (2.2%) and BHC (18.8%) groups, respectively (P < 0.05). Additionally, a statistically significant difference in the Modified Rankin Scale scores of the 2 groups was observed 6 months after the operation (P < 0.05). During the follow-up period, neither group demonstrated any obvious operative complications. CONCLUSIONS: NHE is more effective than BHC for treating sCSDH and is worth popularizing on a large scale; however, ways to better deal with the outer membrane of hematoma warrant further consideration.

Middle Meningeal Artery Embolization in Pediatric Patients.

BACKGROUND: Middle meningeal artery (MMA) embolization has been increasingly applied in adult populations for the treatment of chronic subdural hematomas (cSDH). There is a paucity of literature on the indications, safety, and outcomes of MMA embolization in the pediatric population. SUMMARY: A systematic literature review on pediatric patients undergoing MMA embolization was performed. We also report the case of successful bilateral MMA embolization for persistent subdural hematomas following resection of a juvenile pilocytic astrocytoma. Persistent bilateral subdural hematomas following resection of a large brain tumor resolved following MMA embolization in a 13-year-old male. Indications for MMA embolization in the pediatric literature included cSDH (6/13, 46.2%), treatment or preoperative embolization of arteriovenous fistula or arteriovenous malformation (3/13, 23.1%), preoperative embolization for tumor resection (1/13, 7.7%), or treatment of acute epidural hematoma (1/13, 7.7%). Embolic agents included microspheres or microparticles (2/13, 15.4%), Onyx (3/13, 23.1%), NBCA (3/13, 23.1%), or coils (4/13, 30.8%). KEY MESSAGES: Whereas MMA embolization has primarily been applied in the adult population for subdural hematoma in the setting of cardiac disease and anticoagulant use, we present a novel application of MMA embolization in the management of persistent subdural hematoma following resection of a large space-occupying lesion. A systematic review of MMA embolization in pediatric patients currently shows efficacy; a multi-institutional study is warranted to further refine indications, timing, and safety of the procedure.

Platelet-derived Growth Factor Activates Pericytes in the Microvessels of Chronic Subdural Hematoma Outer Membranes.

Angiogenesis is one of the growth mechanisms of chronic subdural hematoma (CSDH). Pericytes have been implicated in the capillary sprouting during angiogenesis and are involved in brain ischemia and diabetic retinopathy. This study examined the pericyte expressions in CSDH outer membranes obtained during trepanation surgery. Eight samples of CSDH outer membranes and 35 samples of CSDH fluid were included. NG2, N-cadherin, VE-cadherin, Tie-2, endothelial nitric oxide synthase (eNOS), platelet-derived growth factor (PDGF) receptor-ß (PDGFR-ß), a well-known marker of pericytes, phosphorylated PDGFR-ß at Tyr751, and ß-actin expressions, were examined using western blot analysis. PDGFR-ß, N-cadherin, and Tie-2 expression levels were also examined using immunohistochemistry. The concentrations of PDGF-BB in CSDH fluid samples were measured using enzyme-linked immunosorbent assay kits. NG2, N-cadherin, VE-cadherin, Tie-2, eNOS, PDGFR-ß, and eNOS expressions in CSDH outer membranes were confirmed in all cases. Furthermore, phosphorylated PDGFR-ß at Tyr751 was also detected. In addition, PDGFR-ß, N-cadherin, and Tie-2 expressions were localized to the endothelial cells of the vessels within CSDH outer membranes by immunohistochemistry. The concentration of PDGF-BB in CSDH fluids was significantly higher than that in cerebrospinal fluid. These findings indicate that PDGF activates pericytes in the microvessels of CSDH outer membranes and suggest that pericytes are crucial in CSDH angiogenesis through the PDGF/PDGFR-ß signaling pathway.

Middle meningeal artery embolization as standalone treatment versus combined with surgical evacuation for chronic subdural hematomas: systematic review and meta-analysis.

OBJECTIVE: Middle meningeal artery embolization (MMAE) is a novel treatment for chronic subdural hematomas (cSDHs) with high variability of use across practitioners and institutions. This study sought to investigate whether standalone MMAE may be an effective alternative to combined MMAE and surgery for select patients with cSDH. METHODS: The authors searched the Medline and Embase databases for studies reporting outcomes specific to standalone MMAE and combined MMAE and surgery. The Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool was used to assess risk of bias in each included study. Patient characteristics were compared between cohorts, and rates of surgical recurrence of standalone MMAE and combined MMAE and surgery were pooled using random-effects models. RESULTS: Four hundred two unique patients (156 with standalone MMAE and 246 with combined MMAE and surgery) were identified across 8 studies. Overall, the subdural thickness for the standalone MMAE group was modestly but statistically significantly smaller (16.8 vs 18.8 mm, estimated p value 0.002), and the mean follow-up time was significantly longer for the standalone MMAE group (5.4 vs 2.3 months, estimated p value < 0.001); there were no significant differences between age, sex, and anticoagulant use. The surgical recurrence rates were not significantly different between the two groups (estimated p value 0.63). Using random-effects models, the surgical recurrence rates were estimated at 6.8% (95% CI 3.5%-11.2%) and 4.6% (95% CI 2.3%-7.7%) for standalone MMAE and combined MMAE and surgery, respectively. CONCLUSIONS: Standalone MMAE for cSDH may yield a low rate of surgical recurrence, which may be comparable to that of combined MMAE and surgery. However, studies in this systematic review and meta-analysis were primarily single-arm studies prone to treatment bias. Future studies are needed to further investigate whether standalone MMAE may be an effective alternative to combined MMAE and surgical treatment for cSDH in select patients.