The study included patients treated at Nanchong Central Hospital and Guangyuan Central Hospital in Sichuan, China, between July 2020 and February 2026. Eligible patients were 18 to 90 years old, had symptomatic chronic subdural haematoma of at least three weeks’ duration, and had either maximum haematoma thickness above 10 mm or midline shift above 5 mm. Of the 265 participants, 46 received middle meningeal artery embolization, 152 underwent burr hole drainage and 67 received neuroendoscopic-assisted evacuation with middle meningeal artery disconnection.

The primary outcome was radiological recurrence within six months, defined as increased haematoma thickness on follow-up CT, with or without worsening symptoms, regardless of whether further surgery was required. An independent radiologist blinded to treatment allocation re-measured haematoma thickness and midline shift. Secondary outcomes included neurological improvement, defined as a decrease of at least one point on the modified Rankin Scale; reoperation; any additional surgery; complications; operation time; hospital stay; and imaging follow-ups.

Six-month recurrence occurred in 30 of 152 patients treated with burr hole drainage, a rate of 19.74% (95% CI 13.73–26.96%). Recurrence occurred in two of 46 patients treated with embolization, a rate of 4.35% (95% CI 0.53–14.84%), and three of 67 patients treated with neuroendoscopic evacuation and artery disconnection, a rate of 4.48% (95% CI 0.93–12.53%). The overall difference among the three groups was statistically significant (p = 0.001), while the difference between embolization and neuroendoscopic evacuation was not. Recurrence odds were higher with burr hole drainage than with embolization or neuroendoscopic evacuation, and the blinded radiological measurements produced the same group estimates.

Neurological improvement was documented in 59 of 67 patients in the neuroendoscopic group, or 88.06% (95% CI 77.82–94.70%), compared with 71.71% in the burr hole drainage group and 60.87% in the embolization group; the overall difference was significant (p = 0.003). Reoperation for recurrence was required in 19.08% of the burr hole drainage group, compared with 4.35% after embolization and 4.48% after neuroendoscopic evacuation, also a significant overall difference (p = 0.002).

Embolization did not produce the lowest rate under every measure. Five patients, or 10.87% of the embolization group, underwent salvage burr hole drainage during the same hospitalization because of persistent or worsening symptoms without radiological progression. When recurrence-related reoperations and this salvage procedure were combined, any additional surgery occurred in 15.22% of the embolization group, 19.08% of the burr hole drainage group and 4.48% of the neuroendoscopic group. After Bonferroni-corrected pairwise comparisons, the neuroendoscopic group had a significantly lower rate than the burr hole drainage group, but the other pairwise differences were not significant.

The embolization procedure had the shortest median operation time, 31 minutes, compared with 45 minutes for burr hole drainage and 70 minutes for neuroendoscopic evacuation. Median hospital stay was seven days after embolization, nine days after burr hole drainage and eight days after neuroendoscopic evacuation. The embolization and neuroendoscopic groups each had a median of four imaging follow-ups, compared with six in the burr hole drainage group. Complication rates did not differ significantly: 8.70% after embolization, 9.21% after burr hole drainage and 5.97% after neuroendoscopic evacuation.

One patient in the embolization group experienced permanent blindness after inadvertent embolization through a dangerous meningo-ophthalmic anastomosis. No comparable severe event was reported in the other groups. The authors described embolization as offering rapid procedures and low recurrence, but cautioned that it does not immediately remove an established haematoma and that five patients required salvage drainage for delayed resolution of mass effect. Neuroendoscopic evacuation with artery disconnection allowed direct removal of liquid and solid haematoma, coagulation of bleeding points and disruption of fibrous septations, but required the longest operation.

The observational design limits causal interpretation. Treatment was not randomized, and selection may have reflected operator preference, patient willingness and local resources. Although measured baseline characteristics were balanced, unmeasured factors such as frailty, disease severity and operator experience could have influenced the results. The embolization and neuroendoscopic groups were small and had few recurrence events, preventing multivariable adjustment, propensity-score matching and reliable time-to-event analysis. Secondary outcomes were exploratory without correction for multiple testing, and follow-up beyond one year was not established.

Based on the findings and their clinical interpretation, the authors proposed individualized selection that accounts for haematoma characteristics, patient condition and available resources. They presented burr hole drainage as a reasonable option for first-onset, non-septated haematoma; embolization as potentially suitable for older or medically frail patients and those with coagulopathy, subject to caution because of blindness risk; and neuroendoscopic evacuation with artery disconnection as potentially appropriate for septated, organized, recurrent or markedly space-occupying haematomas. The study itself was observational, so these positions require confirmation in larger prospective comparative research.

Subject of Research: Comparative outcomes of three treatments for chronic subdural haematoma in a 265-patient retrospective cohort

Article Title: Comparative outcomes of middle meningeal artery embolization, burr hole drainage, and neuroendoscopic-assisted evacuation with MMA disconnection for chronic subdural haematoma: a multicenter retrospective cohort study

Article References: Song, X., Zhang, Y., Luo, B., & Tang, X. (2026). Comparative outcomes of middle meningeal artery embolization, burr hole drainage, and neuroendoscopic-assisted evacuation with MMA disconnection for chronic subdural haematoma: a multicenter retrospective cohort study. Frontiers in Neurology, 17, Article 1975364. https://doi.org/10.3389/fneur.2026.1975364

Image Credits: AI Generated

DOI: 10.3389/fneur.2026.1975364

Keywords: chronic subdural haematoma, middle meningeal artery embolization, burr hole drainage, middle meningeal artery disconnection, neuroendoscopy, haematoma recurrence, retrospective cohort study, neurological outcome, neurosurgery, Comparative, outcomes, middle

The novel coil procedure was led by David Santiago-Dieppa, MD, a cerebrovascular and endovascular neurosurgeon at UC San Diego Health and associate professor of neurological surgery at the University of California San Diego School of Medicine. According to Santiago-Dieppa, chronic subdural hematoma is an increasingly common condition in neurosurgical practice, and patients stand to benefit from minimally invasive approaches that can reduce the need for repeat operations. The first patient treated with the new coil technology at UC San Diego Health is recovering well, an encouraging early signal as clinicians continue to evaluate the device’s potential. He emphasized that advances in both coil-based and liquid embolization technologies are giving physicians more options to tailor treatment to each patient’s anatomy and clinical needs, with the ultimate goal of more consistently treating the source of these brain bleeds and improving outcomes.

Chronic subdural hematoma develops when blood collects between the brain and its outermost covering, the dura mater, often following a minor head injury that may have seemed trivial at the time. Because the bleeding accumulates slowly over days or weeks, symptoms such as headaches, confusion, memory problems, gait difficulties, and drowsiness can emerge gradually and are sometimes mistaken for normal aging or dementia. The condition is becoming steadily more common for two converging reasons: the population is growing older, and a rising number of people take blood-thinning medications such as anticoagulants and antiplatelet drugs, which impair the body’s ability to stop even small bleeds. That demographic and pharmacological trajectory is what drives the projection that chronic subdural hematoma may top the list of adult cranial neurosurgical conditions within the decade.

For much of modern neurosurgical history, the standard treatment was surgical drainage, in which a surgeon drills one or more small holes in the skull to evacuate the accumulated blood. While often effective, surgery carries risks for elderly patients and, crucially, does not address the underlying vascular source that can allow fluid and blood to reaccumulate. Recurrence rates after drainage alone have historically been a persistent clinical challenge, forcing a subset of patients back to the operating room for repeat procedures that compound their risk and prolong recovery.

In recent years, a minimally invasive alternative called middle meningeal artery embolization has transformed the treatment landscape. The middle meningeal artery, or MMA, is a branch of the external carotid artery that supplies the dura mater and is intimately involved in the formation and persistence of chronic subdural hematomas. During embolization, physicians navigate a tiny microcatheter through the vasculature, typically from an access point in the groin or wrist, until it reaches the MMA. They then deploy an embolic material to block the artery, cutting off the blood supply that feeds the bleed and helping prevent it from returning. Rather than replacing surgery in every case, embolization is often combined with drainage or used in select patients as a stand-alone strategy, and studies have shown it can reduce the likelihood that patients will need additional procedures while potentially improving long-term outcomes.

As MMA embolization has gained widespread adoption, device developers have raced to improve how physicians seal the target artery. Two broad technological philosophies have emerged. Coil-based approaches use specialized metallic coils to mechanically obstruct blood flow within the vessel, while liquid embolic materials are designed to flow with the bloodstream and penetrate smaller vessel branches farther from the treatment site, occluding a more diffuse vascular network. Each strategy has trade-offs related to vessel anatomy, procedural control, and the completeness of closure. The newly introduced coil technology adopted at UC San Diego Health is engineered to help physicians shut down the artery more completely and efficiently than previous generations of embolization coils. Its flexible design allows delivery through small and tortuous blood vessels, and it can treat a longer section of the artery than earlier coils, potentially reducing the number of devices and steps required in a given procedure.

Santiago-Dieppa’s role in the technology extended beyond the operating room. Drawing on extensive experience performing MMA embolization procedures, he provided clinical insights during the device’s development phase, helping shape a tool intended to improve procedural efficiency and the quality of artery closure. That clinician-inventor feedback loop, in which frontline operators inform device design before and after regulatory approval, has become an increasingly important pathway for translating neurovascular innovations into routine practice. It also reflects a broader trend in which academic medical centers serve simultaneously as early adopters, evaluators, and co-developers of emerging technologies.

UC San Diego Health’s leadership in this field is not limited to device adoption. Researchers in the Department of Neurological Surgery at UC San Diego School of Medicine developed the Patency After Coil Embolization, or PACE, scoring system, a standardized method for measuring how completely blood flow through the middle meningeal artery has been eliminated after treatment. The system gives clinicians and researchers a common language for grading technical success, and early research suggests that more complete closure of the artery may be linked to better resolution of the brain bleed over time. By quantifying the degree of occlusion achieved with different devices and techniques, tools like the PACE score help determine which patients benefit most from which embolization strategy, moving the field toward evidence-based personalization.

The institution has also been deeply involved in the clinical trial infrastructure supporting liquid embolic agents. J. Scott Pannell, MD, director of neurointerventional surgery, endovascular neurosurgeon, and neurointerventional radiologist at UC San Diego Health, and professor of neurological surgery and radiology at UC San Diego School of Medicine, served as a site investigator for the EMBOLISE clinical trial, which evaluated the addition of MMA embolization to standard treatment for chronic subdural hematoma. Evidence from that national trial and others supported the recent FDA approval of a liquid embolic for this indication, and Pannell’s involvement helped bring new embolization techniques and clinical research opportunities to patients in San Diego. He noted that the growing body of evidence supporting MMA embolization has fundamentally changed how physicians approach the condition, and that liquid embolic technologies offer a primary option that may allow more complete treatment in select patients. In his view, participation in trials such as EMBOLISE has been critical to understanding how these therapies can improve patient outcomes.

The convergence of these developments, from next-generation coils to approved liquid embolics and standardized occlusion scoring, points toward a future in which chronic subdural hematoma treatment becomes more predictable, effective, and accessible for the growing number of patients diagnosed each year. Physicians can now select among mechanical and liquid occlusion strategies based on vascular anatomy, the extent of dural supply, and patient-specific risk factors, rather than relying on a one-size-fits-all surgical approach. UC San Diego Health, nationally recognized for its treatment of complex brain, spine, and cerebrovascular disorders and ranked among the nation’s best in neurology and neurosurgery in the 2026-2027 U.S. News Best Hospitals rankings, continues to advance this evolution through research, clinical trials, and multidisciplinary care for conditions ranging from stroke and aneurysms to traumatic brain injury. As the population ages and anticoagulant use rises, the ability to treat the vascular source of chronic brain bleeds through a catheter rather than a craniotomy may prove to be one of the most consequential shifts in neurosurgery this decade.

Subject of Research: Minimally invasive middle meningeal artery embolization technologies for chronic subdural hematoma

Article Title: First health system on West Coast to use new brain bleed technologies

Article References: First health system on West Coast to use new brain bleed technologies. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: chronic subdural hematoma, middle meningeal artery embolization, neurosurgery, embolization coils, liquid embolic, UC San Diego Health, EMBOLISE trial, PACE score, minimally invasive procedures, brain bleed, neurointerventional surgery, aging population