Surgical treatment of aneurysms in the M1 segment of the middle cerebral artery (MCA) is associated with a high risk of ischemic stroke in the territory of the lenticulostriate artery (LSA). We retrospectively studied 38 consecutive patients with M1 aneurysms to evaluate the clinical characteristics and surgical outcomes with the background of routine use of indocyanine green (ICG) videoangiography and motor evoked potential (MEP). Between 2011 and 2019, 38 procedures were performed in 38 patients with M1 aneurysms. Of the 38 patients, 12 were men and 26 were women, and the mean age was 60.7 years. The mean size of aneurysm was 5.3 mm. Seventeen aneurysms were located at the origin of the early frontal branch (EFB), 10 at the LSA, and 11 at the anterior temporal artery (ATA). All of the EFB and 7 of the LSA aneurysms showed superior projections, 3 of the LSAs showed posterior projections, and all of the ATA aneurysms showed inferior projections. Seventeen patients (44.7%) had multiple aneurysms, which were most commonly ipsilateral MCA aneurysms. Surgery was performed using the transsylvian approach, with a wide opening of the Sylvian fissure from the distal part to the carotid cistern. More than 70% of the EFB and LSA aneurysms were embedded in the brain, and subpial dissection was necessary in approximately 60% of these cases. Proximity to the LSA was present in 9 of 17 EFB and all LSA aneurysms. Dissection of the LSA was infeasible in four patients, and wrapping was performed in one. A decrease in MEP amplitude was observed in 3 of 36 procedures with MEP monitoring, but it fully recovered after re-adjustment (n=2) or removal (n=1) of the clips. None of the 38 patients developed neurological deficits associated with the surgery. Postoperative diffusion-weighted imaging showed high intensity in the LSA territory in four patients, but the lesions were asymptomatic. Provided that a sufficient operative field is obtained to allow full direct inspection of the aneurysm from multiple angles and careful clipping technique is utilized under appropriate monitoring, surgical clipping of the M1 aneurysm is associated with a very low risk of surgical complications.

Among middle cerebral artery aneurysms, those at the M1 portion of the middle cerebral artery have a lower incidence of occurrence. We retrospectively analyzed and reported the clinical features and management of 12 M1 aneurysms in 12 patients treated with direct clipping. Aneurysms arising at the M1 portion were mostly smaller in size and prevalent in older women, on the left side, with more intracerebral hematoma and less accompanied than those at the bifurcation. Ruptured aneurysms comprised 80% of the aneurysms and were larger than 5 mm in size, while 14.3% of those smaller than 5 mm in size were unruptured. Aneurysms were located in the upper (n=5), downward (n=5), anterior (n=1), and posterior (n=1) directions. Of the five aneurysms in the upper direction, three were in the early frontal branch, one was in the early temporal branch, and one was in the lenticulostriate artery. Two of the aneurysms in the upper direction had an intracerebral hematoma (ICH) in the frontal and temporal lobes, while one aneurysm in the downward direction had an ICH in the temporal lobe. The preoperative clinical grade of M1 aneurysms with ICH was worse than that of bifurcation aneurysms; however, the outcome was equal to that of bifurcation aneurysms.

Aneurysms arising at the M1 portion should be treated with a preoperative meticulous investigation for their anatomical complexity, not only with direct clipping but also with endovascular techniques.

Aim: Rupture of a cerebral aneurysm is often accompanied by intracerebral hematoma or massive subarachnoid hemorrhage. Postoperative hematoma expansion could have adverse effects on patient outcome²⁾. In our hospital’s treatment of ruptured cerebral aneurysms accompanied by hematoma, we focused on the risk of hematoma expansion after acute phase surgery and retrospectively analyzed the perioperative treatment strategy.

Methods: During January 2007-September 2018, 106 patients who met our inclusion criteria were included in this study. We examined the relationship between volume and localization of hematomas, aneurysm treatment, and timing of postoperative anti-vasospasm treatment as factors for postoperative hematoma expansion.

Results: Hematoma expansion was observed in 23 patients (21.7%), and an association between hematoma expansion and worse outcomes was observed. The initiation of anti-vasospastic drugs was earlier in this group. Hematoma expansion occurred in 9.1% of patients who underwent clipping procedures─significantly lower than the 42.5% of patients who underwent coil embolization procedures (p=0.0001). A high rate of increase in Sylvian fissure hematomas was observed (p＜0.05).

Summary: In the treatment of ruptured aneurysms accompanied by hematomas, prevention of hematoma expansion may contribute to improved outcomes. Elapsed time from the onset to embolization was implicated as an effector of hematoma expansion associated with coil embolization. Therefore, it may be better to select clipping when possible and to initiate administration of anti-vasospastic drugs 24 hours postoperatively.

Introduction: Clinicians still disagree about whether stent-assisted coil embolization (SAC) should be used to treat intracranial ruptured aneurysms in the acute stage. In the present series, we analyzed the clinical results of SAC in acutely ruptured cerebral aneurysms that were treated using a stent-assisted technique.

Materials and Methods: 101 consecutive patients with 126 acutely ruptured aneurysms were treated using endovascular therapy in our department between September 2014 and February 2019. The clinical outcomes were compared between SAC (S) and non-SAC (nS) groups.

Results: The patients’ characteristics were as follows: male/female, 30/71; average age, 63.9 years (range, 38-95 years); World Federation of Neurosurgeons (WFNS) grade IV and V (59.4%). Nineteen patients (18.8%) were treated using SAC; the other 82 were treated using simple coil embolization. In the S group, dual or triple antiplatelet medication through a gastric tube was started before stent deployment. Stents were deployed to cover the wide neck of the aneurysms in nine cases. In six cases, stents were deployed to preserve important branching arteries. In one case, the stent was deployed to treat fusiform aneurysms. In another case, the stent was deployed to divert flow. In two cases, the stent was deployed to secure the migrated coils from the aneurysms. Regarding the types of aneurysm in the SAC group, 10 were saccular type, seven dissection type, and two fusiform type. Seven aneurysms were located at the internal carotid artery, Three at the anterior communicating artery, two at the middle cerebral artery, one at the posterior cerebral artery, and six at the vertebrobasilar artery. The average aneurysm neck size was significantly different between the S and nS groups (5.0 mm vs. 3.3 mm, respectively; p = 0.0124). Perioperative complications occurred in 10/19 patients in the S group and in 11/82 patients in the nS group (p = 0.0005). In the S group, five aneurysms were thromboembolic complications, two were stent occlusions (one in the acute period and one in the late period), two were re-bleeds of aneurysms that occurred between 24 hours and 5 days after the procedure, and one was a cerebral hemorrhage. The morbidity and mortality rate was 21.1% (4/19) in the S group and 4.9% (4/82) in the nS group (p = 0.0391).

Conclusion: Although SAC carries a higher complication rate than non-SAC in patients with acute subarachnoid hemorrhage (SAH), it can be an alternative treatment if other options are hindered by poor grade, older age, or surgical difficulty.

The incidence of de novo intracranial aneurysm development and enlargement of untreated additional aneurysms is still unknown and requires further research. Over a 15.4-year period, the authors performed clinical surveillance in 748 consecutive patients with clip-ligated unruptured intracranial aneurysms. Serial magnetic resonance angiography was performed in 702 patients for 5.3±3.3 years. During 3716.3 patient-years of follow-up, the incidence of de novo aneurysm formation was 0.27%/patient-year. The cumulative incidence of de novo aneurysm development was 0.5%, 3.3%, and 6.4% at 5, 10, and 15 years, respectively. A total of 114 additional aneurysms were seen in 107 patients Over 621.8 patient-years of follow-up, the annual risk of aneurysm growth was 2.7%. The cumulative incidence of additional aneurysm growth was 12.5%, 28.6%, and 59.5% at 5, 10, and 15 years, respectively. None of the factors including sex, age, history of hypertension, history of smoking, family history of subarachnoid hemorrhage, multiplicity, and size of untreated aneurysm were statistically significant predictors of de novo aneurysmal formation or growth of additional aneurysms. The annual incidence of interventional processes (surgical clipping or coil embolization) was 0.73%/patient-year. Patients with clip-ligated unruptured intracranial aneurysms should be continuously monitored for a long period, and appropriate interventions should be considered according to neuroradiological findings to prevent the development of subarachnoid hemorrhages.

We herein report a rare case of improvement of unilateral sensorineural hearing loss after endovascular treatment for symptomatic vertebral artery stenosis. A 69-year-old man was admitted to our institution because of gait disturbance, dizziness, and hearing loss on the left ear. Magnetic resonance imaging (MR) showed multiple infarcts in the cerebellum and brain stem due to severe left vertebral artery stenosis. Although he received intensive medical treatment, his condition continued to worsen, and so a percutaneous transluminal angioplasty (PTA) was performed. Symptoms including hearing loss improved after PTA.

Ischemic disease involving the vertebrobasilar artery can cause hearing loss due to hindered blood flow to the anterior inferior cerebellar artery (AICA), and we considered that revascularization procedures, such as PTA, can potentially be useful in reversing such conditions.

Symptomatic common carotid artery occlusion (CCAO) is relatively rare. This case study reports on a 68-year-old woman who presented with moderate aphasia and right hemiparesis and underwent carotid endarterectomy (CEA) for managing CCAO. Magnetic resonance imaging (MRI) showed multiple infarctions in the watershed area of the left subcortical white matter. Angiography demonstrated left CCAO with preservation of the internal carotid artery (ICA) and collateral filling of the external carotid artery (ECA) from the superior thyroid artery via the inferior thyroid artery. Because the occluded segment of the left common carotid artery (CCA) was short, CEA was performed for managing CCAO. The procedure was performed 7 weeks after the onset. Postoperative MRI revealed no new ischemic lesions. Direct CEA for treating short-segment CCAO with preservation of the ICA can be safely performed using the following three key steps: 1) adequate exposure of the proximal CCA, 2) appropriate removal of the thrombus in the occluded CCA, and 3) appropriate order of releasing the clamp in consideration of the collateral circulation.

We report a rare case of a ruptured internal carotid-posterior communicating artery (IC-PC) aneurysm forming kissing aneurysms with an unruptured C2 aneurysm. A 60-year-old woman was transferred to our hospital due to subarachnoid hemorrhage (Hunt & Kosnik Grade I, WFNS Grade I). At the time of admission, she had a mild headache for ten days and no neurological abnormality. Three-dimensional computed tomographic angiography (3D-CTA) revealed a right IC-PC and C2 aneurysm, which were observed to be in contact with each other. After the right internal carotid artery was exposed in the neck, right frontotemporal craniotomy was performed to obliterate the aneurysms on the day after admission. Intraoperative findings demonstrated a ruptured right IC-PC aneurysm adhered to an unruptured C2 aneurysm. Neck clipping was performed with meticulous dissection, especially between both aneurysmal domes. She was discharged without any neurological deficits 2 weeks postoperatively and has since resumed her previous work. Due to the difficulty in dissecting fibrous adherence, the operation for kissing aneurysms has been recognized as challenging. We emphasize that sufficient preoperative discussion, careful intraoperative observation, and meticulous dissection with temporary occlusion of the parent artery are necessary to have good outcomes.

We propose a novel surgical method termed “Jumping Bypass” to prevent hyperperfusion and to reduce the risk of uneven distribution of cerebral blood flow when performing an emergency superficial temporal artery (STA)-middle cerebral artery bypass to treat progressive atherosclerotic cerebral infarction. This method aims to improve blood circulation in two distant areas and to reduce the risk of hyperperfusion using a single STA as a bypass route for establishing side-to-side and sideto-end anastomoses. The presented case is of an atherosclerotic stroke in a 79-year-old woman. After a single STA was secured, the proximal part was anastomosed side-to-side to an artery on the temporal lobe, and the STA at the distal part was anastomosed to a branch on the frontal lobe. This method resulted in the rapid recovery of symptoms without resulting in hyperperfusion syndrome. This may be a useful surgical method in situations where hyperperfusion is unavoidable or when a single bypass may result in an uneven blood flow distribution.

We report a case of a ruptured lenticulostriate artery (LSA) aneurysm, associated with moyamoya disease, which was removed surgically. A 25-year-old female presented with right intraventricular hemorrhage. Cerebral angiography revealed moyamoya disease and a right LSA aneurysm. Antihypertensive therapy was initially administered, followed by a scheduled bypass. On day 5, rebleeding was noted and cerebral angiography on day 9 showed aneurysmal enlargement. We performed bypass surgery (superficial temporal artery-middle cerebral artery and encephalo-myo-synangiosis) to prevent further rebleeding. A high intensity lesion on T1 weighted magnetic resonance imaging (MRI) was observed around the aneurysm on the 5^th postoperative day. Repeat cerebral angiography showed residual aneurysm. Therefore, rerupture of the aneurysm was anticipated. Because the aneurysm was fusiform in shape, trapping and excision was performed on day 16. Postoperatively, the patient had transient left hemiparesis. Three months later, her modified Rankin Scale improved from 4 to 1. Histopathological diagnosis showed a true aneurysm based on the thin aneurysmal body wall and smooth muscle. For cases wherein a residual aneurysm is present and reruptures after bypass, surgical treatment for the aneurysm is required. Surgical intervention, in the form of excision or clipping, might be effective for the treatment of ruptured aneurysms associated with moyamoya disease to prevent rerupture during the acute phase.

Suturing of arteriotomy is the most crucial step in carotid endarterectomy (CEA). We modified our suturing technique to simplify it and compared it with previous other methods. Following arteriotomy and plaque removal, the center of arteriotomy is sutured as a stay suture. Subsequently, running sutures are initiated from the internal carotid artery (ICA) side to the center and completed by tying with the central stay suture. Another running suture is initiated from the common carotid artery (CCA) side to the center. The last three sutures are kept loose to irrigate the lumen and flush the open arteriotomy. The thread of the loosened suture is tightened, and the closure is completed by tying with the central stay suture. Several methods for closure of arteriotomy have been reported combining running or interrupted sutures in CEA. Our novel tightening technique was developed based on a cardio-vascular surgery technique, and it provided quick closure after the flushing step. In surgical procedures, preference is given to simple techniques to avoid complications.