First Reported Recurrence After Aneurysm Electrocoagulation Treated With Surgical Clipping

A ruptured aneurysm on a rarely affected stretch of the brain’s anterior cerebral artery has, for the first time, been documented to grow back after being sealed off with a technique that uses an electrified guidewire to provoke clotting inside the lesion. In a case report published in Chinese Neurosurgical Journal, neurosurgeons describe how a tiny blister-like aneurysm at the A1 segment of the right anterior cerebral artery, initially obliterated by pure micro-guidewire electrocoagulation, was found to have recanalized at a five-week follow-up scan. The recurrent aneurysm was then successfully closed with a surgical clip, and the operation gave the team a direct, magnified view of what the electrocoagulation procedure had actually left behind inside the vessel wall.

The patient was a 51-year-old woman who arrived with sudden-onset headache, nausea and vomiting. Computed tomography showed a diffuse subarachnoid hemorrhage, the bleeding into the fluid-filled spaces around the brain that signals a ruptured aneurysm, distributed mainly in the interpeduncular cistern and the right sylvian fissure. She was neurologically intact apart from neck stiffness, corresponding to Hunt and Hess grade II, and she had a three-year history of hypertension. Digital subtraction angiography revealed the culprit: a tiny aneurysm at the origin of the right anterior cerebral artery, measuring roughly 0.9 by 2.5 millimeters, with a blister-like appearance and a neck narrower than half a millimeter.

Aneurysms at the A1 segment, the first portion of the anterior cerebral artery, are uncommon, accounting for approximately one percent of all intracranial aneurysms according to prior studies cited by the authors. Both of the standard treatment routes are difficult there. Surgical clipping is complicated by anatomical variability and by the cluster of important perforating arteries that supply deep brain structures, and postero-superiorly directed sacs are often buried in orbitofrontal cortex and entangled with perforators, raising the risk of intraoperative rupture and perforator injury. Endovascular treatment, meanwhile, is hampered by the sharp turning angle the microcatheter must negotiate from the parent artery into a predominantly posteriorly pointing sac.

One day after the hemorrhage began, the patient was transferred to a tertiary center where coil embolization was the intended treatment. She received loading doses of aspirin and clopidogrel two hours before the procedure in case a stent proved necessary. During the intervention, an Echelon-10 microcatheter was used, and although a Traxcess-14 guidewire successfully entered the aneurysm, the microcatheter repeatedly failed to follow because of the extremely narrow neck and the challenging angle of the parent artery. With conventional catheter-based delivery impossible, the team turned to a salvage option: pure micro-guidewire electrocoagulation, in which the guidewire tip itself becomes the treatment instrument.

The technique exploits the electrical properties of blood. With the guidewire tip positioned inside the aneurysm cavity and the microcatheter advanced close to the neck, the proximal end of the wire was connected to a Solitaire stent detachment system. Energy was delivered at 4.0 volts and 1.0 milliampere in one-minute cycles, parameters chosen on the basis of previously reported protocols. The negatively charged wire tip acts as an anode, attracting negatively charged blood particles and promoting thrombus formation within the aneurysm cavity. After five cycles, with angiography repeated after each one, the aneurysm no longer opacified, and a check twenty minutes later confirmed complete occlusion. A computed tomography angiogram two days after the procedure showed no filling of the aneurysm, and the patient made a full neurological recovery without new deficits.

Because the technique is still experimental, the team advised early surveillance, and that vigilance proved decisive. At five weeks postoperatively, a follow-up CTA showed recanalization of the aneurysm at its original site, a finding confirmed by digital subtraction angiography. The patient was referred for retreatment, and the clinicians chose surgical clipping over a repeat endovascular attempt in order to achieve a more definitive result. Using a lateral frontal approach and working through the carotid cistern, they found the recurrent, yellowish aneurysm on the dorsal side of the proximal A1 segment. Notably, the operation revealed that the aneurysm neck arose from the junction of a small perforating branch and the parent artery, a relationship the prior angiograms had not shown, and the lumen of that perforator appeared to have thrombosed.

After careful dissection of the neck, the aneurysm was completely obliterated with a straight mini clip. The patient recovered without neurological deficits and was discharged one week after surgery. A CTA performed one month later demonstrated persistent obliteration of the aneurysm and good positioning of the clip, and she is scheduled for a follow-up angiogram at six months postoperatively. Beyond securing the lesion, the surgery offered something no imaging study could: a direct microscopic view of the treated aneurysm. The wall had developed fibrous hyperplasia and become opaque, changes the authors suggest could relate to an inflammatory response caused by the thermal effect, and the origin of the adherent perforating artery had become occluded, a finding that raises concern about a risk of perforator infarction associated with electrocoagulation.

The recurrence is significant because of what has come before. The authors note that a few case reports and small series have described pure micro-guidewire electrocoagulation as a practicable option for ruptured aneurysms that cannot be catheterized, and that in the limited published experience totaling nineteen patients, no recurrence had previously been reported after initial total occlusion. Lu and colleagues described the largest series, seven microcatheter-inaccessible ruptured aneurysms successfully occluded without rebleeding or recurrence during follow-up. The present case is therefore the first documented recurrence after endovascular electrocoagulation, a fact the authors say raises concern about the durability of the technique and underscores the importance of early angiographic follow-up after treatment.

Why the clot failed to hold is not known for certain, and the authors are careful to frame their explanation as hypothesis. They suggest that persistent hemodynamic stress on the dorsal aspect of the A1 segment may have disrupted unstable fresh thrombi, and that the delivered energy, while sufficient to achieve initial occlusion, may have been insufficient to induce durable endothelial fibrosis and remodeling of the vessel wall. They also acknowledge a sobering trade-off: although angiography during the initial procedure showed no excessive thrombosis or compromised flow in the parent artery, the direct surgical view revealed an occluded adjacent perforator, likely related to thermal spread. Past studies have reported acute lacunar infarctions related to the electrocoagulation procedure, and the authors write that further research is needed to determine optimal parameters that balance therapeutic effect against collateral damage.

The report carries explicit limitations that shape how its findings should be read. The exact timing of recanalization is unknown, because no imaging was obtained between postoperative day two and week five. Although the patient remained neurologically intact, small lacunar infarcts related to perforator occlusion could not be fully excluded, since no postprocedural diffusion-weighted imaging was performed. The precise mechanism of recurrence remains unclear and unstudied. As a single-case account, the report cannot establish how often such failures occur, and the authors themselves note that more research is needed to evaluate the efficacy of electrocoagulation, which has so far been applied only to ruptured aneurysms that resist microcatheter access. Their conclusion is measured: even when immediate angiographic occlusion is achieved, aneurysms treated this way carry a risk of recanalization, and close angiographic follow-up is warranted to verify that the treatment has held.

Subject of Research: Recurrence of a ruptured A1 segment aneurysm after endovascular electrocoagulation and its retreatment with surgical clipping

Article Title: Surgical clipping for a recurrent perforator aneurysm of the A1 segment following endovascular electrocoagulation therapy: a case report

Article References: Li, M., Wang, Z., Cui, Q., & Wang, D. (2026). Surgical clipping for a recurrent perforator aneurysm of the A1 segment following endovascular electrocoagulation therapy: a case report. Chinese Neurosurgical Journal, 12(1), Article 29. https://doi.org/10.1186/s41016-026-00448-4

Image Credits: AI Generated

DOI: 10.1186/s41016-026-00448-4

Keywords: intracranial aneurysm, endovascular electrocoagulation, micro-guidewire, A1 segment, anterior cerebral artery, subarachnoid hemorrhage, surgical clipping, aneurysm recurrence, perforator aneurysm, case report, angiographic follow-up, Chinese Neurosurgical Journal