Surgical considerations and techniques using intraoperative indocyanine green angiography for ethmoidal dural arteriovenous fistula.

OBJECTIVE: This study aims to investigate the efficacy of microsurgery with intraoperative indocyanine green (ICG) angiography as a treatment approach for ethmoidal dural arteriovenous fistula (DAVF). METHODS: Between January 2010 and July 2021, our institution encountered a total of eight cases of ethmoidal DAVF. In each of these cases, microsurgical treatment was undertaken utilizing a bilateral sub-frontal interhemispheric approach, with the aid of intraoperative ICG angiography. RESULTS: ICG angiography identified bilateral venous drainage with single dominance in four cases (50%) of ethmoidal DAVF, a finding that eluded detection during preoperative transfemoral cerebral angiography (TFCA). The application of microsurgical treatment, in conjunction with intraoperative ICG angiography, resulted in consistently positive clinical outcomes for all patients, as evaluated using the Glasgow Outcome Scale (GOS) at the 6-month postoperative follow-up assessment; six patients showed GOS score of 5, while the remaining two patients attained a GOS score of 4. CONCLUSIONS: The use of intraoperative ICG angiography enabled accurate identification of both dominant and non-dominant venous drainage patterns, ensuring complete disconnection of the fistula and reducing the risk of recurrence.

Bench-top Comparison of Physical Properties of 4 Commercially-Available Self-Expanding Intracranial Stents.

PURPOSE: To better understand the performance of four commercially available neurovascular stents in intracranial aneurysm embolization, the stents were compared in terms of their basic morphological and mechanical properties. MATERIALS AND METHODS: Four different types of stents that are currently being used for cerebral aneurysm embolization were prepared (two stents per type). Two were laser-cut stents (Neuroform and Enterprise) and two were braided from a single nitinol wire (LEO and LVIS stents). All were subjected to quantitative measurements of stent size, pore density, metal coverage, the force needed to load, push, and deploy the stent, radial force on deployment, surface roughness, and corrosion resistance. RESULTS: Compared to their nominal diameters, all stents had greater diameters after deployment. The length generally decreased after deployment. This was particularly marked in the braided stents. The braided stents also had higher pore densities than the laser-cut stents. Metal coverage was highest in the LEO stent (14%) and lowest in the Enterprise stent (5%). The LIVS stent had the highest microcatheter loading force (81.5 gf). The LEO stent had the highest passage force (55.0 gf) and deployment force (78.9 gf). The LVIS and LEO stents had the highest perpendicular (37.1 gf) and circumferential (178.4 gf) radial forces, respectively. The Enterprise stent had the roughest stent wire, followed by the LVIS, LEO, and Neuroform stents. CONCLUSION: The four neurovascular stent types differed in terms of morphological and physical characteristics. An understanding of this diversity may help to decide which stent is most suitable for specific clinical situations.

Concomitant origin of the anterior or posterior spinal artery with the feeder of a spinal dural arteriovenous fistula (SDAVF).

BACKGROUND/OBJECTIVE: The concomitant origin of the anterior spinal artery (ASA) or the posterior spinal artery (PSA) from the feeder of a spinal dural arteriovenous fistula (SDAVF) is rare and the exact incidence is not known. We present our experience with the management of SDAVFs in such cases. METHODS: In 63 patients with SDAVF between 1993 and 2015, the feeder origin of the SDAVF was evaluated to determine whether it was concomitant with the origin of the ASA or PSA. Embolization was attempted when the patient did not want open surgery and an endovascular approach was regarded as safe and possible. The outcome of the procedure was evaluated as complete, partial, or no obliteration. The clinical outcome was evaluated by Aminoff-Logue (ALS) gait and micturition scale scores. RESULTS: Nine patients (14%) had a concomitant origin of the ASA or PSA with the feeder. There were two cervical, five thoracic, and two lumbar level SDAVFs. A concomitant origin of the feeder was identified with the ASA (n=7) and PSA (n=2). Embolization was performed in four patients and open surgery was performed in five. Embolization resulted in complete obliteration in three patients and partial obliteration in one. Using the ALS gait and micturition scale, the final outcome improved in six while three cases remained in an unchanged condition over 2-148 months. CONCLUSIONS: The concomitant origin of the ASA or PSA with the feeder occurs occasionally. Complete obliteration of the fistula can be achieved either by embolization or open surgery. Embolization can be carefully performed in selected patients who are in a poor condition and do not want to undergo open surgery.

Medical Problems during Participation of Medical Congress - A Long Trip to Val D'Isere from Korea.

Since the 3rd WIN meeting in 1982 more than 500 participants join the meeting in Val D'Isere every year [1]. One of our authors has attended the meeting more than 10 times. He experienced many physical illnesses while travelling from South Korea to Val D'Isere in France, which is located in the Alps mountain near the border between France and Italy. In order to get there, it is necessary to take airplane, train, and/or bus with a heavy suitcase. During the trip which usually takes more than 15 hours, he experienced headache, gastrointestinal trouble, sleep disturbance and other additional physical illnesses. Therefore, we reviewed the itinerary to Val D'Isere and presented physical illnesses which occurred during a long trip for an academic activity by specialized professionals such as university hospital professors. In addition, we discussed the mechanism of such illnesses and offered possible solutions including medical treatment.

Easy Advancement of a Large-Profile Microcatheter (Excelsior XT27™) by Parallel Use of Two Microguidewires For Stent Delivery.

PURPOSE: In the endovascular treatment of cerebral aneurysms, navigating a large-bore microcatheter for delivery of an open-cell stent can be challenging, especially in wide-necked bifurcation aneurysms. We were able to overcome this difficulty by parallel use of two microguidewires through the stent-delivery microcatheter. MATERIALS AND METHODS: From December 2014 to April 2015, we treated 15 patients with wide-necked bifurcation aneurysms. For stent delivery, we used a 300-cm 0.014-in microguidewire (Transend), which was placed into the target branch using an exchange technique. A 0.027-in microcatheter (Excelsior XT-27), which was designed for the stent, was advanced over the exchange microguidewire. If we had trouble in advancing the microcatheter over the exchange microguidewire, we inserted a regular microguidewire (Traxcess), into the microcatheter lumen in a parallel fashion. We also analyzed the mechanism underlying microcatheter positioning failure and the success rate of the 'parallel-wire technique'. RESULTS: Among the 15 cases, we faced with navigation difficulty in five patients. In those five cases, we could advance the microcatheter successfully by applying the parallel-wire technique. There were no procedure-related complications. CONCLUSION: Simply by using another microguidewire together with pre-existing microguidewire in a parallel fashion, the stent-delivery microcatheter can be easily navigated into the target location in case of any advancement difficulty.

"Two-coil technique" for embolization of small internal carotid artery aneurysms incorporating the origin of the anterior choroidal artery.

PURPOSE: The purpose of this article is to evaluate the efficacy, safety and stability of the "two-coil technique." MATERIALS AND METHODS: We evaluated a single-center experience by using a two-coil technique, which is a variation of the multiple-microcatheter technique in the treatment of a small internal carotid artery aneurysm with its sac incorporated with the origin of the anterior choroidal artery. Six consecutive patients with small ICA aneurysms with its sac incorporated with origin of the anterior choroidal artery and treated with the two-coil technique were included in this study. We finished the embolization with only two coils introduced via two different microcatheters without any other device assistance in all cases. Embolization status was determined at immediate postoperative and follow-up angiography after six months. RESULTS: The two-coil technique was technically successful in five of six cases; one case was converted to surgical clipping because of persistent occlusion of the anterior choroidal artery after several attempts. On follow-up study, all five cases showed stable occlusion status without recanalization or residual aneurysm. CONCLUSIONS: The two-coil technique has potential to be used for coiling small aneurysms, particularly where there is an important branch incorporated into the sac or neck of the aneurysm.

Does a Low-wall Coverage Stent Have a Flow Diverting Effect in Small Aneurysms?

BACKBROUND AND PURPOSE: The flow diverting effect of a low-wall coverage stent remains controversial. We evaluted patients who underwent stenting for small aneurysms with a low but potential risk of growth and reviewed related literature. MATERIALS AND METHODS: We evaluated 9 small aneurysms among 19 unruptured intracranial aneurysms from eight patients who underwent stenting. The patients had unexplainable severe headache (n = 8), aneurysm originating from the anterior choroidal artery (n = 3), potential growth or rupture risks including hypertension (n = 5), and multiple aneurysms (n = 6). Stents with a relatively low-wall coverage ratio (8-10%) were used. Clinical and angiographic outcomes were assessed. RESULTS: One (n = 8) or two stents (n = 1) were used without any procedural difficulties or complications. Although no immediate changes of aneurysm morphology were observed, aneurysms decreased in size (n = 8) when examined by DSA (n = 8) or MRA (n = 1) during a median 28.9-month follow-up. There were no adverse events, including thromboembolism, aneurysm rupture, or stent movement during a median 31.9-month clinical follow-up (range: 17-69 months). CONCLUSION: Although a variable degree of aneurysm size decrease may not prevent further growth or rupture of small aneurysms, stenting with a low-wall coverage ratio may have some advantageous hemodynamic effect. Flow modification of stent architecture vs. aneurysm characteristics, including size and location, on long-term outcome, requires further clarification.

Anesthetic consideration for neurointerventional procedures.

Interventional neuroradiology (INR) has been a rapidly expanding and advancing clinical area during the past few decades. As the complexity and diversity of INR procedures increases, the demand for anesthesia also increases. Anesthesia for interventional neuroradiology is a challenge for the anesthesiologist due to the unfamiliar working environment which the anesthesiologist must consider, as well as the unique neuro-interventional components. This review provides an overview of the anesthetic options and specific consideration of the anesthesia requirements for each procedure. We also introduce the anesthetic management for interventional neuroradiology performed in our medical institution.