Hello everyone, we will be presenting our case series on awake transradial middle meningeal artery embolization and twist-drill craniostomy for chronic subdural hematomas. Chronic subdural hematomas are a common neurosurgical problem associated with significant morbidity and mortality, especially in the elderly. Minimally invasive treatment paradigms could help improve outcomes. Middle meningeal artery, or MMA, embolization targets the underlying capillary beds supplying fibrocellular neomembranes that are thought to potentiate chronic subdural hematomas. SEPs, or subdural evacuating port system, allows for a bedside burr hole drainage of the hematoma and evacuation of the hematoma without the need for surgery. We compare our case series using these two combined approaches as primary treatment for chronic subdurals and compare that to patients undergoing operative intervention in the operating room with MMA embolization and SEPs alone, or operative intervention alone. Our methods for this study was to conduct a retrospective analysis of all 250 patients in a span of four years at our institution who underwent treatment for subdural hematomas. 23 patients underwent a combined approach of MMA embolization and placement of SEPs compared to 23 patients who underwent MMA embolization and operative intervention and 19 who underwent SEPs alone and 185 patients who underwent operative intervention alone. Outcome measures including modified Rankin score at discharge, length of stay, recurrence, discharge disposition, readmission, mortality, and complications were recorded and compared. Here in this figure we demonstrate an example of a patient who underwent an MMA embolization as well as a SEPs placement. A shows the pre-procedural CT scan showing a 2 cm thick subdural hematoma that's homogenous in nature, it's a chronic subdural. B shows the CT scan post-procedurally, the day of, and C is a 6 week post-op scan demonstrating resolution of the hematoma. In our case series, MMA embolization was done through the transradial route and was done awake negating the need for general anesthesia and the risks it carries. This figure demonstrates an example of MMA embolization, E and F demonstrate AP and lateral projections of the right MMA before embolization, G and H specifically demonstrate the capillary infiltration and blood supply to the neomembranes which is the target for embolization, I and J demonstrate during the embolization process where PVA particles specifically sized 45-150 nm are injected into the MMA through a microcatheter, and K and L demonstrate post-embolization runs of the right MMA demonstrating complete obliteration of the blood supply to those neomembranes. After completing the MMA embolization procedure in the same setting in the neurointerventional suite under local anesthesia, a twist drill craniostomy is performed to place a CEP strain. The drilling is done at the skull at a predetermined site where the subdural hematoma is thickest. Upon sharply puncturing the dura and confirming hematoma evacuation, a bolt is secured in place at the skull and that is attached to a drainage tube which connects to a bulb drain on compression. Here a 3D reconstruction of a CT scan shows the bolt in place in the subdural space and a post-procedure axial CT scan shows expected pneumocephalus but mostly resolved hematoma. In comparing our combined treatment cohort with other patients that were treated for chronic subdural hematomas, we demonstrate that there is a significant difference in age in those patients who underwent the combined approach being much older than those who underwent the operative intervention. In addition, there was a difference in anticoagulation use with those undergoing MMA CEP embolization having higher percentages of anticoagulation use and also having higher rates of core morbidities such as heart failure and abnormal liver function. In addition, their mean INR was slightly higher and as you can see, most of these patients were done awake. When comparing outcome measures to operative intervention alone, the combined minimally invasive treatment method decreases mean length of stay drastically from 12.2 days to 7.2 days. This makes sense since that minimally invasive approach requires much less recovery time. Additionally, when compared to CEPs alone, the MMA embolization plus CEPs procedure decreases 60 day recurrence significantly, decreasing it from 46.7% to 9.1%. The MMA embolization plus CEPs cohort demonstrated to be much older and sicker in terms of co-morbidities. Even though this makes it harder to compare the groups in terms of outcomes, it does reflect the real world need for minimally invasive techniques for this higher at-risk population. Additionally, to summarize, this group had less recurrence compared to the CEPs only group and also had decreased length of stay compared to the operative group. Obviously, limitations of this study include a single center retrospective design with a small sample size. Given our experience with the combined treatment cohort, we've developed an algorithm which we recommend to be followed in treating chronic subdural hematomas. If the patient is rapidly worsening or has significant clinical symptoms, they should still be taken to the operating room as long as hemodynamically stable and a craniotomy or burr hole craniostomies should be performed. If there is minimal to no midline shift or the size of the subdural is smaller than 1cm and not causing any focal deficits, then conservative treatment can be used with or without MMA embolization to prevent growth or recurrence. If there is mass effect and the subdural hematoma is greater than 1cm in size, then one must assess age and risk factors. For elderly patients, we prefer to do the combined treatment, especially when they have many comorbidities or are on anticoagulation and antiplatelet medication. Typically, these patients are also at higher risk for operative intervention. If the patient is younger than 70 years old, with few comorbidities, and a good surgical candidate, operative intervention can also be considered with MMA embolization. In conclusion, the MMA embolization and SEPs combined treatment paradigm appears to be safe and effective treatment, especially for elderly patients with significant operative risk factors. This treatment may reduce length of stay, as well as hematoma recurrence. Obviously, further investigation of this treatment paradigm is warranted with larger sample sizes and longer follow up. These are our references, and thank you for your time.

awake transradial MMA embolization

twist-drill craniostomy

chronic subdural hematomas

minimally invasive treatment

MMA embolization and SEPs placement