Chronic subdural hematoma (CSDH) is a prevalent medical condition with potentially severe consequences if left untreated. While surgical removal has traditionally been the standard approach for treatment, middle meningeal artery (MMA) embolization has emerged as a promising minimally invasive alternative to reduce recurrences. This comprehensive review provides the general radiology community with an overview of MMA embolization as a therapeutic option for managing CSDH. The authors base their insights on existing evidence and their institutional experience. This overview encompasses the pathophysiology of CSDH as well as the potential advantages and limitations, safety profile, and potential complications of MMA embolization as compared with surgical treatment. The imaging findings seen before and after MMA, as well as insights into the procedural techniques used at the authors' institution, are described. On the basis of reports in the current literature, MMA embolization appears to be a safe and effective therapeutic option for managing CSDH, especially in patients who are unsuitable for surgery or at risk for recurrence. Nonetheless, further research is needed to validate these findings. Results from ongoing clinical trials hold promise for future validation and the establishment of scientific evidence. ^©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Chatterjee in this issue.

Background: Chronic subdural hematoma (CSDH) is a common condition in older adults with rising rates of incidence. While burr hole drainage remains the standard treatment, it is associated with significant recurrence and complications. This study assesses MMA embolization with Squid, both as a standalone procedure and as an adjunct to surgery. Methods: Our prospective registry included 101 patients with 134 CSDH cases treated at two tertiary care centers from December 2020 to January 2024. Patients were divided into two groups: embolization alone and embolization combined with surgery. Demographic, clinical, radiological, and procedural data were collected. Follow-up imaging was conducted at 1, 3, and 6 months. Treatment failure was defined as rescue surgery, hematoma thickness ≥ 10 mm, midline shift > 3 mm at 6 months, or procedure-related death. Results: Fifty-two patients (51.5%) underwent combined treatment, and forty-nine (48.5%) received embolization alone. Most were men (68.3%) and the median age was 82 years. Combined-treatment patients had larger hematomas and more symptoms. Procedures were performed under general anesthesia in 72.3% of patients, with radial and femoral access used equally frequently, and 32.7% underwent bilateral embolization. Patients’ hematoma thickness in follow-up imaging showed a significant decrease (p = 0.000), reaching a median of 0 mm at six months, with no significant difference between groups. Complications occurred in 5.9%, and treatment failure in 4%. Mortality was higher in the embolization-only group, likely reflecting greater rates of comorbidities. Conclusions: This study supports the use of MMA embolization with Squid as a safe and effective treatment for CSDH. Comparable procedural and radiological outcomes in both groups suggest embolization alone may suffice in select patients, offering a less invasive alternative.

Background and Importance: Cauda equina radicular arteriovenous fistulas are rare “low flow” shunting lesions characterized by direct communication between the radicular artery and vein of a cauda equina nerve root. None have been associated with hereditary hemorrhagic telangiectasia and a high-flow cauda equina radicular arteriovenous fistula has never been reported. We present a unique case of a high-flow cauda equina radicular arteriovenous fistula in a patient with hereditary hemorrhagic telangiectasia. Marked flow-induced vascular remodeling posed significant diagnostic and therapeutic challenges which will be highlighted in this report. Clinical Presentation: A 39-year-old female with genetically confirmed hereditary hemorrhagic telangiectasia presented with progressive thoracic myelopathy secondary to a high-flow single-hole arteriovenous fistula below the conus. The feeding artery, arising from the anterior spinal artery, and draining vein had a paramedian course, favoring the diagnosis of a cauda equina radicular arteriovenous fistula (supplied by a proximal radicular artery) over a filum terminale arteriovenous fistula. Transarterial embolization was attempted but significant elongation and tortuosity of the anterior spinal artery precluded microcatheter access to the fistulous point. Surgical disconnection was successfully performed. The intraoperative findings supported the diagnosis of cauda equina radicular arteriovenous fistula. Delayed neurologic deterioration secondary to overshooting venous thrombosis was observed. She recovered after the initiation of therapeutic anticoagulation. Conclusion: To the best of our knowledge, we hereby report the first high-flow cauda equina radicular arteriovenous fistula. The accurate differentiation of cauda equina radicular arteriovenous fistula from filum terminale arteriovenous fistulas, while challenging, is important to avoid treatment-related complications. Careful preoperative planning, the use of specialized endovascular and surgical techniques, and meticulous postoperative care can ensure the safe and complete disconnection of high-flow cauda equina radicular arteriovenous fistulas.