Treatment Of Ruptured Tiny Intracranial Aneurysms By Electrocoagulation With Guidewire Manipulation:12 Cases Report

Background: Ruptured tiny intracranial aneurysm (RTIA) is particularly rare seen. Treatment of RTIA is more dicult and not under control. Methods: We hereby present twelve rare cases of RTIA that were diagnosed based on DSA. These patients were found due to spontaneous or traumatic SAH, 11 of whom were treated only by electrocoagulation, and one of whom was treated by stent-assisted coiling and electrocoagulation. Results: There were eight patients with aneurysms located in posterior circulation and four patients with aneurysms located in anterior circulation. 11 patients were cured only by electrocoagulation merely: ten patient’ RTIA disappeared completely and immediately and another patient’s RTIA was thrombosed two months later. The twelfth patient was carried out stent-assisted coiling and electrocoagulation. The twelve patients’ average follow-up time was 12.5 months and the outcomes were all surprisingly excellent. No revascularization of aneurysm was found. Conclusions: Electrocoagulation with guidewire manipulation is a suitable method to treat RTIA. While large-scale studies with long-term follow-up are required to validate these promising results.

Background RTIA, generally considered to be those of 3mm diameter or smaller, pose special technical challenges for endovascular surgeons. RTIA is particularly rare seen, representing approximately 1% of all intracranial aneurysms, and 0.5-2% of all ruptured aneurysms [1]. With the widespread adoption of threedimensional (3D) rotational angiography, RTIA has been more frequently diagnosed, which has previously been considered to have a high rate of intraprocedural ruptures. It is a tough problem for neurosurgeons to choose appropriate operations because of more aggressive behaviors compared with saccular aneurysms and more occurred intra-operative complications [2].There are more probabilities to recur and rebleed in perioperative period. A previous meta-analysis that included only seven studies observed is latively high complication rate, especially in terms of periprocedural rupture risk [3]. Electrocoagulation was applied to treat non-intracranial aneurysm in 19 th century, which could promote thrombosis in aneurysm. Youxiang Li was the rst to cure intracranial aneurysms through electrocoagulation technology [4].

Baseline Characteristics
We enrolled 12 patients with tiny intracranial aneurysms in our department to adopt endovascular treatment with guidewire electrocoagulation technology from January 2017 to October 2019, and all patients suffered subarachnoid hemorrhage (SAH). There were ve male patients and seven female patients, with the ages ranging from six years old to 60 years old. The six-year-old female patient was found due to traumatic subarachnoid hemorrhage and the others were middle-aged and elder patients found because of spontaneous SAH. The twelve patients were examined based on Hunt-Hess grades that six patients suffered with grade I, four patients with grade II and two patients with grade III. All patients received endovascular treatment within seven days after symptom onset.

Aneurysms Image
All patients took intracranial computerized tomography (CT) to verify SAH before endovascular treatment. RTIA was con rmed by Digital Subtraction Angiography (DSA) in multi-angular rotation. Table   1 showed that there were eight patients with aneurysms located in posterior circulation and four patients with aneurysms located in anterior circulation. Common coiling method was di cult for this kind of aneurysms.

Operation
The endovascular treatment was carried out under general anesthesia and systemic heparinization to prevent arterial thromboses. The operator performed right femoral artery Seldinger puncture and put into a 6F artery sheath. After reshaping the tip of guidewire according to the angle between aneurysm and parent artery, we introduced the Traxcess 14 guidewire (Microvention, Columbia Aliso Viejo, USA) into the RTIA, advanced the microcatheter close to the pedicle, connected Traxcess to the Solitaire stent detachment system (ev3 Neurovascular, Irvine, USA) at about 4V and 1.0 mA electronic current, and passed current through it for 4 min, which was repeated for 3-5 times. 11 patients were carried out above procedure. But for the 6-year-old girl, we performed right femoral artery Seldinger puncture and put into a 5F artery sheath, DSA showed aneurysm was enlarged from 0.7×1.2mm (Fig 1a) to 3×3mm (Fig 1b) in two weeks, so that the risk of rebleeding increased. The RTIA was lled with 4 coils (Fig 1c) (Axium QC-2-6-Helix, NC-2-6-Helix, QC-1.5-4-Helix, APB-1-3 -HX-ES), then using jailing technique with a LVIS stent(3.5-15, Microvention, Columbia Aliso Viejo, USA). However there was a small cavity in the in ow tract, no more coils could be lled into it. The Nylon coil was in our expectation to promote thrombosis. One week later, unfortunately, the cavity was enlarged again (Fig 1d). The operator expected electrocoagulation would take effect, which we carried out three times (Fig 1e), then the cavity disappeared completely and immediately.
Postoperative Treatment and Follow-up After the procedure, heparin was neutralized naturally, and the patient returned to NICU after waking up under anesthesia. Analgesia, hypotensive medical treatment and nimodipine, a kind of anti-vasospasm medicine, were given; intracranial CT was performed again within one day after the procedure. It was recommended that follow-up DSA should be performed in the third month and at the end of the rst year.
Patients, who are unable to receive follow-up DSA, should be instructed to receive CTA and followed up by telephone review (Table 1).

Results
It was found in the patients by DSA that RTIAs were located at the initial site of tiny perforating branch artery or the wall of the unbranched blood vessel. Embolization was effective in treating aneurysms with guidewire electrocoagulation technology (Fig 2). In general, decreasing times of electrocoagulation were found in patients with the narrower aneurysm neck, which made aneurysms occluded faster. Through DSA, complete embolization of aneurysms was seen in 11 patients and incomplete embolization of aneurysms at aneurysm neck was seen in 1patient. The latter received follow-up DSA within two months and the result showed the aneurysm was delayed to be cured (Fig 3).
No complications existed in all patients. High-density thrombus image was seen by DSA after endovascular treatment with guidewire electrocoagulation technology in some patients, and it was not implicated in the parent artery and peripheral perforating branch artery. Meanwhile, it was observed the thrombus in aneurysms would not reach the parent artery for 15 min during the procedure. Except for the six-year-old girl, anticoagulant or antiplatelet medical therapy was not applied to the thrombus in aneurysms after the procedure. The six-year-old girl was required to take 75mg Plavix orally each day for three months and 50mg Aspirin orally each day for six months. Symptoms of hemorrhage and ischemic stroke were not found in all patients and they were discharged from hospital within two weeks after endovascular treatment with guidewire electrocoagulation technology.

Follow-up Results
The twelve patients' average follow-up time was 12.5 months (Table 1). Five patients received follow-up by DSA; three patients received follow-up by CTA and four patients received follow-up by telephone. Recurrent aneurysms were not found in those patients who had received image examination, and all patients had favorable clinical outcomes and did not have SAH again during follow-up period.

Discussions
Because of the small diameter of the RTIA, it is di cult to clip. During the cliping process, it is easily to tear the neck of the RTIA and the clip is easily to loosen or fall off. Compared with the clipping group, it was less frequently for the endovascular treatment related complications to occur. Furthermore, the following technical factor is closely associated with the successful endovascular treatment with a low risk of intraprocedural rupture [5]. The International Subarachnoid Aneurysm Trial (ISAT) showed better independent survival at one year for patients with coiled ruptured intracranial aneurysms compared with clipping [6].
Endovascular treatment offers a lower morbidity-mortality rate compared with surgical approaches, but the process is also di cult. For example, it is di cult to make microcatheter into aneurysm; even if it is successful, the stability is poor; the rate of rerupture during the lling process is high; it is di cult to compact embolization, and the rate of rebleeding after operation is high. Coil embolization of RTIA is particularly challenging due to the thin fragile wall of small intracranial aneurysms, with limited space to obtain a stable microcatheter position for coil deployment [7,8]. Recently, multilayer ow-diverting stents appear to be a promising strategy [9] , but covered stent technology can only be used in limited cases because perforator artery is probably covered by the stent. It is di cult to treat RTIA with conventional methods, and the electrocoagulation shows the advantages of being easy to operate and getting reliable results in our department' treatment of 12 patients.
Here summarized the technical points of electrocoagulation: 1. The tip of the microcatheter is close to the opening of the aneurysm, so it does not need to enter the aneurysm cavity so as to reduce the risk of perforation.
3. The positive wire is connected to the uncoated part at the tail end of the micro guiedwire, and the negative wire is connected to the steel needle which is tied in the groin skin.
6. Because of the high risk caused by too many times electrocoagulation, the patients who did not form complete thrombus immediately after electrocoagulation could wait for delayed thrombus formation.
The main concern about this guidewire electrocoagulation technology is its durability. But the twelve patients' average follow-up time was 12.5 months which fully proved the excellent short-term effectiveness. Guidewire manipulation provides a new thought when microcatheter could not be navigated into the aneurysm. With the exception of RTIA whether it can be applied to other vascular diseases, like arteriovenous malformation, dural arteriovenous stulas or other small vascular diseases, needs further exploration.

Conclusion
Electrocoagulation with guidewire manipulation represents a new thought in the technique of RTIA treatment, which is effective and safe through short-term observation. Larger studies with long-term follow-up are required to validate these promising results. This study has been approved by the Ethics Committee in the hospital and the authors obtained informed consent from the patient and his family.

Consent for publication
The authors obtained consent for publication from the patient. Figure 1 a-f: The patient presented epilepsy and coma after head trauma. DSA showed RTIA in right internal carotid artery(0.7×1.2mm)(a). After two weeks, the RTIA was enlarged to 3×3mm(b). Stent assistedcoiling was ful lled with a small cavity in the in ow tract(c). One week later, the cavity was enlarged again(d). We carried out the electrocoagulation for 4min, which was repeated for another three times, then the cavity disappeared completely and immediately(e). DSA and VASO CT after three months showed no recurrence(f). DSA after 27 months showed no recurrence, either(g).