Wonhyoung Park

Occipital Artery–Posterior Inferior Cerebellar Artery Bypass for the Treatment of Aneurysms Arising from the Vertebral Artery and Its Branches

OBJECTIVE To report experience with 7 cases of intracranial aneurysms of the vertebral artery (VA) and its branches that were treated with occipital artery (OA)-posterior inferior cerebellar artery (PICA) bypass. METHODS Over 4 years, 7 cases of intracranial aneurysms arising from the VA and its branches were treated with OA-PICA bypass. The clinical data, characteristics of aneurysms, and results of treatment were analyzed. RESULTS There were 4 aneurysms that arose from the VA-PICA junction, 2 aneurysms that occurred at the distal PICA, and 1 aneurysm that occurred at the collateral artery from the distal end of the occluded VA to the ipsilateral PICA. OA-PICA bypass was performed before obliteration of the aneurysms in all patients. Of the 7 aneurysms, 4 were totally obliterated with surgery, 2 were treated with additional endovascular coiling or trapping, and 1 was partially obliterated by surgery and gradually disappeared during the follow-up period. Postoperative angiography revealed that the patency of the grafts was good in 6 patients. In 1 patient with an occluded bypass graft, multiple infarctions developed in the left cerebellum, but the patient had almost fully recovered after rehabilitation. CONCLUSIONS OA-PICA bypass with obliteration of the aneurysm is one of the optimal treatments for intracranial aneurysms that occur at the VA and its branches because it can preserve the perforators and distal blood flow from the PICA.

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.

Hemodynamic Characteristics Regarding Recanalization of Completely Coiled Aneurysms: Computational Fluid Dynamic Analysis Using Virtual Models Comparison.

Purpose Hemodynamic factors are considered to play an important role in initiation and progression of the recurrence after endosaccular coiling of the intracranial aneurysms. We made paired virtual models of completely coiled aneurysms which were subsequently recanalized and compared to identify hemodynamic characteristics related to the recurred aneurysmal sac. Materials and Methods We created paired virtual models of computational fluid dynamics (CFD) in five aneurysms which were initially regarded as having achieved complete occlusion and then recurred during follow-up. Paired virtual models consisted of the CFD model of 3D rotational angiography obtained in the recurred aneurysm and the control model of the initial, parent artery after artificial removal of the coiled and recanalized aneurysm. Using the CFD analysis of the virtual model, we analyzed the hemodynamic characteristics on the neck of each aneurysm before and after its recurrence. Results High wall shear stress (WSS) was identified at the cross-sectionally identified aneurysm neck at which recurrence developed in all cases. A small vortex formation with relatively low velocity in front of the neck was also identified in four cases. The aneurysm recurrence locations corresponded to the location of high WSS and/or small vortex formation. Conclusion Recanalized aneurysms revealed increased WSS and small vortex formation at the cross-sectional neck of the aneurysm. This observation may partially explain the hemodynamic causes of future recanalization after coil embolization.

Surgical Flow Alteration for the Treatment of Intracranial Aneurysms That Are Unclippable, Untrappable, and Uncoilable

Objective The treatment of complex intracranial aneurysms remains challenging. One approach is the application of surgical flow alteration to treat aneurysms that are neither clippable, trappable, or coilable. The efficacy and limitations of surgical flow alteration have not yet been established. Methods Cases of complex aneurysms treated with surgical flow alteration (proximal occlusion with or without bypass, distal occlusion with or without bypass and bypass only) were included in this retrospective study. Results Among a total of 16 cases, there were 7 giant aneurysms (≥25 mm diameter) and 9 large aneurysms (>10 mm diameter); 15 of 16 aneurysms were unruptured. There were 8 aneurysms located in the anterior circulation, while the other 8 were in the posterior circulation. Aneurysms were treated with proximal occlusion in 10 cases and distal occlusion in 5 cases; in 1 case, the aneurysm occluded spontaneously after bypass without parent artery occlusion. All but 2 cases underwent prior or concurrent bypass surgery. Complete obliteration of the aneurysm at the latest imaging follow-up was shown in 12 of 16 cases (75.0%). Bypass patency was confirmed in 13 of 15 cases (86.7%). Surgery-related morbidity developed in 3 cases (18.8%, Glasgow outcome scale of 4) and all were perforator infarctions. There were no mortalities. Conclusion Surgical flow alteration resulted in a high rate of aneurysmal obliteration with acceptable morbidity. Although several limitations remained, it could represent an alternative method for treating complex aneurysms.

Outpatient Day-care Neuroangiography and Neurointervention of Unruptured Intracranial Aneurysms

Purpose Day-care management of unruptured intracranial aneurysms can shorten hospital stay, reduce medical cost and improve outcome. We present the process, outcome and duration of hospital stay for the management of unruptured intracranial aneurysms via a neurointervention clinic in a single center during the past four years. Materials and Methods We analyzed 403 patients who were referred to Neurointervention Clinic at Asan Medical Center for aneurysm evaluation between January 1, 2011 and December 31, 2014. There were 141 (41%) diagnostic catheter angiographies, 202 (59%) neurointerventional procedures and 2 (0.6%) neurointerventional procedures followed by operation. We analyzed the process, outcome of angiography or neurointervention, and duration of hospital stay. Results There was no aneurysm in 58 patients who were reported as having an aneurysm in MRA or CTA (14 %). Among 345 patients with aneurysm, there were 283 patients with a single aneurysm (82%) and 62 patients with multiple aneurysms (n=62, 18%). Aneurysm coiling was performed in 202 patients (59%), surgical clipping in 14 patients (4%), coiling followed by clipping in 2 patients (0.6%) and no intervention was required in 127 patients (37%). The hospital stay for diagnostic angiography was less than 6 hours and the mean duration of hospital stay was 2.1 days for neurointervention. There were 4 procedure-related adverse events (2%) including 3 minor and 1 major ischemic strokes. Conclusion Our study revealed that day-care management of unruptured intracranial aneurysms could be performed without an additional risk. It could enable rapid patient flow, shorten hospital stay and thus reduce hospital costs.

Anterior Optic Pathway Compression Due to Internal Carotid Artery Aneurysms: Neurosurgical Management and Outcomes

Background and Purpose Compression of the anterior optic pathway results in visual deficits that can lead to the detection of unruptured aneurysms in the internal carotid artery (ICA). The general types of treatment modalities for aneurysms and visual deficits include surgery and endosaccular coiling. This study retrospectively analyzed and compared the resolution of visual deficits following surgery or endosaccular coiling. Methods We reviewed data on 33 patients with unruptured ICA aneurysms who presented with visual field deficits caused by mass effects over the anterior optic pathway. Statistical analyses were performed to identify the variables associated with the recovery of visual symptoms. Results Eighteen patients underwent aneurysm clipping, 2 underwent bypass surgery with endovascular trapping, and 2 underwent endovascular trapping without bypass surgery (group A). Ten patients received endosaccular coiling (group B). The visual outcomes included the following: in group A, 17 patients (73.9%) demonstrated improvement and 6 patients (26.1%) demonstrated no changes or worse outcomes; in group B, 2 patients (20.0%) demonstrated improvement and 8 patients (80.0%) demonstrated no changes or worse outcomes. Group A was associated with a higher rate of favorable outcome than group B (P = 0.007). According to the multivariate analysis, treatment without endosaccular coiling (group A) was the only variable significantly associated with improvement of visual outcome (P = 0.005; OR = 28.523; 95% CI = 2.683-303.171). Conclusions Treatment modality was the only predictor of improvement in visual deficits. Treatment without endosaccular coiling resulted in visual improvement significantly more often in comparison with endosaccular coiling.

Fracture and migration of a retained wire into the thoracic cavity after endovascular neurointervention: report of 2 cases

Although extremely rare, retention of foreign bodies such as microcatheters or micro guidewires can occur during various neurovascular procedures due to gluing of the microcatheter tip or entanglement of the micro guidewire tip with intravascular devices. The authors have experienced 2 cases of irresolvable wire retention, one after flow diverter placement for a left cavernous internal carotid artery aneurysm and the other after intracranial stenting for acute basilar artery occlusion. The first patient presented 6 weeks after her procedure with right lung parenchymal hemorrhage due to direct piercing of the lung parenchyma after the retained wire fractured and migrated out of the aortic arch. The second patient presented 4 years after his procedure with pneumothorax due to migration of the fractured guidewire segment into the right thoracic cavity. In this report, the authors discuss the possible mechanisms of these unusual complications and how to prevent delayed consequences from a retained intravascular metallic wire.

Treatment of Large and Giant Middle Cerebral Artery Aneurysms: Risk Factors for Unfavorable Outcomes

OBJECTIVE This study aimed to assess the clinical and radiologic outcomes after neurosurgical treatment of large and giant aneurysms of the middle cerebral artery (MCA). In addition, we aimed to identify risk factors for unfavorable outcomes. METHODS This retrospective study included 105 patients with 106 large or giant MCA aneurysms treated with neurosurgical methods, including microsurgery and endovascular treatment, over a 15-year period. RESULTS The mean aneurysm size was 15.3 ± 7.1 mm. Ten (9.4%) were giant aneurysms. The MCA bifurcation was the most common aneurysm site, followed by the MCA trunk and distal MCA. Aneurysm clipping was the most common treatment method, followed by clipping or trapping with bypass surgery and endovascular treatment. However, acute cerebral infarction was the most common complication (16.0%), poor outcomes (modified Rankin Scale score, 3-6) developed in 12.3% of aneurysms after treatment, and 6.6% of treated aneurysms needed retreatment. Multivariate analysis showed that independent risk factors for acute cerebral infarction after treatment were aneurysms located on the MCA trunk and 2 or more underlying diseases. Initial presentation with subarachnoid hemorrhage and complications during treatment were independent risk factors for poor outcomes. In addition, endosaccular coiling was an independent risk factor for retreatment. CONCLUSIONS Neurosurgical management should be considered a priority for large and giant MCA aneurysms because of the high rupture rate and clinical symptoms. However, treatment outcomes remain unsatisfactory. Therefore, tailored management with consideration of risk factors for unfavorable outcomes should be implemented.

Intraprocedural Rupture of Unruptured Cerebral Aneurysms During Coil Embolization: A Single-Center Experience

OBJECTIVE Incidence of intraprocedural rupture (IPR) during endovascular coiling is reported to be 2%-5%. We reviewed a single-center experience of IPR during coil embolization of unruptured intracranial aneurysms. METHODS Between January 2011 and April 2016, 849 patients were treated with endovascular therapy for unruptured intracranial aneurysm. IPR was documented in 10 (1.18%) of these patients. We reviewed medical records to evaluate characteristics of the aneurysms, angiographic findings related to rupture, management, and outcomes. RESULTS Among the 10 patients, there were 4 internal carotid artery aneurysms, 3 anterior communicating artery aneurysms, 2 basilar tip aneurysms, and 1 middle cerebral artery aneurysm. The probable mechanism of IPR in 7 patients was focal coil mass distention. Two patients underwent rupture owing to injury by a microcatheter tip that was related to device-device interaction. In 1 patient who had no other clear etiology, increased intra-arterial pressure induced by contrast injection was suspected as a cause of rupture. In all cases, rapid occlusion at the point of suspected leakage was performed, and final angiography showed complete obliteration of the aneurysm. After the procedure, neurologic deterioration was demonstrated in 2 patients. The modified Rankin Scale score at 6-month follow-up was 0 in 7 of the patients. CONCLUSIONS Incidence of IPR during endovascular coiling of unruptured aneurysms is relatively low. Early detection followed by rapid occlusion of the aneurysm can lead to a benign clinical course in most cases.

Fusion 3-Dimensional Angiography of Both Internal Carotid Arteries in the Evaluation of Anterior Communicating Artery Aneurysms

BACKGROUND To determine whether fusion 3-dimensional (3D) angiography of both internal carotid arteries can better disclose vascular details in patients diagnosed with anterior communicating artery (ACoA) aneurysms by computed tomography angiography (CTA) or magnetic resonance angiography (MRA). METHODS Thirty-eight patients diagnosed with ACoA aneurysms by CTA or MRA were evaluated by the new postprocessing feature, fusion 3D angiography, with results individually interpreted by 4 experts. Those experts compared fusion 3D angiography with dominant A1 side single 3D angiography to define advantages and disadvantages for ACoA aneurysms. Patients with unilateral A1 aplasia or rudimentary A1 were excluded. Patients who showed any disadvantages with this additional feature were classified as group 1, those with no advantages were classified as group 2, those with 1 or 2 advantages were classified as group 3, and those with 3 or more advantages were classified as group 4. Radiologic and clinical results were also evaluated. RESULTS Of the 38 patients, 33 (87%) benefited from fusion 3D angiography, including 17 in group 3 and 16 in group 4; of the remaining patients, 1 was classified as group 1 and 4 were classified as group 2. Representative 5 categories of advantage to fusion angiography were found and summarized by the 4 experts. All 33 patients showed defining the exact anatomy of the ACoA, and 22 (67%) showed full angiographic features of A2 or A3, including branches. CONCLUSIONS Fusion 3D angiography can significantly contribute to a better understanding of the complex anatomy of the anterior cerebral artery-ACoA complex, which is essential for successful treatment planning for ACoA aneurysms.