Indications for revascularization surgery in adult patients with ischemic moyamoya disease remain unclear. The Japanese Guidelines for the Management of Stroke 2019 do not distinguish surgical indications for adult versus pediatric patients. I propose the following therapeutic policies for adult patients with ischemic moyamoya disease. 1) Presence or absence of misery perfusion in the affected cerebral hemisphere determined according to presence or absence of reduced cerebral blood flow on brain perfusion single-photon emission computed tomography (SPECT) rather than reduced cerebrovascular reactivity to acetazolamide. 2) Patients with an affected hemisphere without reduced cerebral blood flow treated with antiplatelet therapy using cilostazole alone rather than revascularization surgery. 3) Patients with reduced cerebral blood flow in the affected hemisphere underwent hyperventilation-loaded brain perfusion SPECT using a technetium-99m-labeled tracer to assess cerebrovascular contraction reactivity. 4) No reduction in cerebrovascular contraction reactivity and treatment with revascularization surgery including arterial bypass surgery. Considering the high risk of postoperative cerebral hyperperfusion, patients with reduced cerebrovascular contraction reactivity should undergo revascularization surgery.

Carotid endarterectomy (CEA) remains an effective treatment for severe carotid artery stenosis in symptomatic and asymptomatic patients. Therefore, CEA is an essential surgical technique for neurosurgeons to perform. In this study, we describe preoperative and operational maneuvers and techniques for CEA. When done under general anesthesia, neuromonitoring offers better sensitivity for predicting postoperative neurological deficits. Individual surgeons must opt for a selective or routine shunt that they are more comfortable with. The neck is extended and turned away from the side being operated on. Longitudinal or combined skin incisions is common. Most surgeons use a microscope to dissect the artery and plaque. Surgeons cut the ansa cervicalis at the origin to lift the hypoglossal nerve for dissection of the highly positioned plaque. If the occipital artery disturb to secure the distal internal carotid artery (ICA) site, it can be cut. Patch angioplasty reduces the risk of stroke and restenosis compared with primary closure. However, only a few surgeons in Japan perform patch angioplasty; most surgeons encounter only a small volume of CEA cases in Japan. Therefore, training programs and the development of in vivo training models are important.

Percutaneous transluminal angioplasty (PTA) is a common method for severe intracranial artery stenosis treatment. Vascular dissection is a common complication of PTA, and its risks cannot be completely avoided. This study discusses the follow-up evaluations of PTA-induced dissections. We identified 11 dissected lesions (13.4%) among the 82 lesions for which PTA was performed to treat symptomatic intracranial artery stenosis in our hospital between April 2012 and March 2019. Of the dissected lesions, three (3.7%) were accompanied by symptomatic events and remaining eight lesions were asymptomatic.

In the aforementioned three lesions, vessel flow improved in two lesions, but fresh infarctions were apparent in the perforator area. Another lesion showed symptomatic occlusion. In the 10 non-occluded dissected lesions, stents were used for the rescue of two dissected lesions in the acute phase, neither of which showed restenosis for at least half a year.

In contrast, we observed remnant flow in eight lesions. Seven lesions showed no restenosis; however, one lesion required additional therapy for restenosis within half a year.

These results suggest that the dissected lesions of the intracranial arteries caused by PTA showing the preservation of the true lumen with normal flow might be successfully managed with medical treatment alone. Stents may be useful for rescue from severely dissected stenosis with flow reduction.

The twig-like middle cerebral artery (T-MCA) is a rare disease, and its nature remains unclear. Herein, we report eight cases of T-MCA. We analyzed the structure of the twigs (plexiform arterial networks) and the risk of stroke in asymptomatic patients with the review of related literature.

Eight patients (four men and four women aged 20–68 years, mean age: 50.1 years) with T-MCA (five right sides and three left sides) were reported in our department between 2008 and 2020. Seven patients were asymptomatic and one had a transient ischemic attack (TIA) on presentation.

Based on radiological findings, the twigs were supplied mainly by two different types of arterial channels. One artery originated from the anterior cerebral artery (A1/A2), and the other from the internal carotid artery, including the anterior choroidal artery. These two types of arterial channels are similar to the already-known anomalous arteries, accessory MCA and duplicated MCA.

Through a literature search, 28 cases of asymptomatic T-MCA were identified, including our seven cases; 26 of these 28 cases were subjected to conservative treatment. Of the 26 patients, 8 (30.8%) had a stroke during follow-up (TIA: 1, infarction: 1, intracerebral hemorrhage: 2, and subarachnoid hemorrhage: 4). All strokes, regardless of type, occurred exclusively on the side of the hemisphere with the T-MCA. Asymptomatic patients with T-MCA should be carefully monitored while paying attention to the risk of stroke.

Purpose: Acute cerebral infarction due to basilar artery occlusion (BAO) has a poor prognosis and is characterized by a high mortality rate. Moreover, the efficacy of mechanical thrombectomy (MT) and its indications for BAO have yet to be established. In the present study, we retrospectively investigated the prognostic factors of MT for BAO at our hospital.

Patients and Methods: This study included 13 consecutive patients (eight men, mean age 76 years) who underwent acute-stage revascularization at our hospital for cerebral infarction associated with basilar artery occlusion over a 66-month period from January 2014 to June 2019. Background and treatment-associated factors of each patient were retrospectively identified, and patient outcomes after 90 days (modified Rankin Scale [mRS] score) were investigated by assigning post-operative patients to the good outcome group (mRS score 0–2) or the poor outcome group (mRS score 3–6) and examining their respective associations with each potential prognostic factor. The following six factors were selected: pre-operative National Institutes of Health Stroke Scale (NIHSS) score, posterior circulation Alberta Stroke Program Early CT Score on diffusion-weighted imaging, time from disease onset or final confirmation of good health to recanalization, thrombolysis in cerebral infarction (TICI) classification, collateral blood circulation from the anterior circulation, and basilar artery occlusion site.

Results: The recanalization rate in patients with a TICI grade ≥ 2B was 91%. The good outcome group included 31% of study participants, and the mortality rate was 23%. The mean time to recanalization was 332 min (range: 140–720 min), and the mean pre-operative NIHSS score was 17 (range: 3–30). Associations between background factors and outcomes after 90 days were investigated using the Student’s t-test, and the results showed that a pre-operative NIHSS score ≤ 13 was a significant indicator of a good outcome (p=0.029). None of the other factors was associated with the outcome.

Conclusion: The findings of this study revealed that proactive therapeutic interventions in patients with BAO with an NIHSS score ≤13 significantly improved outcomes.

Direct clipping of large or giant internal carotid artery (ICA) aneurysms is often difficult for various reasons. Flow alteration (FA) using bypass and parent artery occlusion (PAO) could be an alternative treatment for such aneurysms. We retrospectively reviewed 32 patients with large or giant ICA aneurysms who were surgically treated between 2014 and 2018. Aneurysms were divided into three groups, based on location: C3–5 segment (17 cases), C2 segment (including C2–3; 7 cases), and C1 segment (including C1–2; 8 cases). The treatment methods and surgical outcomes were assessed for each group. Postoperative outcomes were evaluated at 6 months using the modified Rankin Scale (mRS). All patients with an aneurysm at the C3–5 segment were treated with FA using PAO with highflow bypass. Treatment-associated mRS score deterioration was observed in one patient (6%) with cerebral infarction. Direct clipping was performed in all patients with C2 segment aneurysms. The mRS score deteriorated in two patients (18%). However, no ischemic complications occurred in the perforator area. Among patients with aneurysms at the C1 segment, six underwent direct clipping, one underwent FA using PAO with bypass, and one underwent trapping with bypass. Deterioration of the mRS score was observed in three patients (38%), including two patients with perforator infarction. Among patients treated with FA, delayed recanalization and aneurysm enlargement occurred. In conclusion, favorable outcomes were achieved following the surgical treatment of large or giant ICA aneurysms located at the C2–5 segment. However, aneurysms located at the C1 segment of the ICA are still associated with complications.

We report a case of ruptured distal posterior inferior cerebellar artery (PICA) aneurysm with large hematoma in the fourth ventricle that was treated by endovascular therapy after endoscopic evacuation of the hematoma.

A 65-year-old man presented with a deep coma and was transferred to our hospital. Computed tomography (CT) scan revealed a large hematoma in the fourth ventricle. CT angiography did not demonstrate any aneurysms. Thereafter, emergent endoscopic evacuation of the hematoma was performed to relieve brain stem compression and hydrocephalus. Cerebral angiography was done immediately after the operation, and a distal PICA aneurysm was detected. The aneurysm was treated by coil embolization. The patient was able to walk with a cane and was discharged after undergoing rehabilitation for seven months.

Coil embolization after endoscopic evacuation of hematoma may improve the outcome of patients with large cerebellar hemorrhage caused by ruptured aneurysm.

The authors report a case of bilateral cervical internal carotid artery dissection (CICAD) presenting as a unilateral tandem occlusion stroke, in which endovascular treatment was effective in restoring cerebral perfusion and facilitating closure of dissected lesions. A 40-year-old man presented with left hemiparesis that developed three days after the onset of headache. The patient had a concomitant, smooth, tapered luminal occlusion of the right internal carotid artery (ICA) origin, and complete occlusion of the right M1 middle cerebral artery (MCA) segment. The patient underwent mechanical thrombectomy for right MCA occlusion after administration of recombinant tissue-plasminogen activator to restore cerebral blood flow, followed by emergent stenting of the right cervical internal carotid lesion. The left CICAD was treated successfully with tandem stenting in the subacute stage, due to worsening of dissection resulting in ICA stenosis. It is important to consider the hemodynamic changes due to dissection in the endovascular treatment of bilateral CICAD, especially with a tandem occlusive lesion.

Treatment of a blood blister-like aneurysm (BBA) of the internal carotid artery (ICA) is challenging in terms of preservation of the anterior choroidal artery (AChA), particularly when it is located distal to the posterior communicating artery of the ICA (C1 portion). A 40-year-old man presented with a subarachnoid hemorrhage caused by BBA rupture at the C1 portion of the ICA, which is at the level of origin of the AChA. The aneurysm was carefully clipped during the first surgery. Computed tomography angiography performed immediately after the operation showed aneurysmal resolution. However, on postoperative day 8, angiography revealed that the aneurysm had recurred. In the second operation, to preserve the AChA originating at the level of the BBA, the aneurysm was treated by ligation of the cervical ICA with high-flow bypass. Postoperative angiography revealed aneurysmal resolution with AChA preservation. The postoperative course was uneventful, and no ischemic complications were observed. Although ICA trapping with bypass is a curative treatment for ICA-BBA, it may lead to severe ischemic complications, especially when the origin of the AChA is involved. BBA curability is controversial; however, proximal ICA ligation with high-flow bypass is an effective treatment for BBA involving a critical perforator such as the AChA.

There is no consensus regarding the treatment of symptomatic common carotid artery occlusion (CCAO) or stenosis of common as well as internal carotid arteries (ICAs). We report a case of symptomatic left ICA stenosis and concomitant ipsilateral chronic CCAO treated with carotid endarterectomy (CEA). A 73-year-old man was admitted to our institution twice due to repeated infarctions. Repeated digital subtraction angiography demonstrated progressive stenosis of the left ICA origin and concomitant ipsilateral chronic CCAO. Single-photon emission computed tomography (SPECT) did not reveal any significant laterality. Therefore, rather than hemodynamic ischemia, atherothrombosis from the plaque at the ICA origin was presumed to cause repeated infarction. The patient underwent CEA limited to the ICA, considering the etiology of the infarction and surgical invasiveness. The postoperative course was uneventful. Ischemic attacks were not observed for 6 months postoperatively.

Scalp arteriovenous malformations (scalp AVMs) are extremely rare. We report a case of excision of a giant scalp AVM. A 45-year-old man developed a subcutaneous hematoma involving the right occiput secondary to a head bruise in childhood. He subsequently observed a soft mass in the same area. His family noticed enlargement of the mass, and he was referred to our department for further evaluation. Angiography revealed a vascular malformation with the occipital and superficial temporal arteries as feeding arteries and the superficial temporal and posterior auricular veins as draining veins. The patient was diagnosed with a scalp AVM, which we excised. Total surgical excision is preferred for scalp AVMs because ligation of feeding arteries alone or inadequate embolization may result in recurrence and AVM enlargement from residual lesions secondary to collateral tract formation. It is important to control blood flow to the lesion, to reduce intraoperative blood loss to the greatest extent possible, and to prevent postoperative complications such as skin infection and necrosis. Preoperative imaging is important for comprehensive evaluation of feeding and draining vessels and to aid with development of an optimal surgical strategy.

Endoscopic hematoma evacuation is a widely used procedure for the treatment of hypertensive cerebral hemorrhage that is less invasive. Several points should be considered for performing it safely, and the washing technique is a significant step to keep a clear surgical field. In our hospital, an irrigation tube is connected to a small hole near the end of the transparent sheath, to facilitate the injection of an artificial cerebrospinal fluid using the foot pedal. The endoscope tip and the inside of the sheath are washed as per the operator’s timing, the collapsed hematoma cavity is expanded, and a clear surgical field is maintained. Confirmation of the bleeding point in the wet field is also made possible by perfusion of adequate flow quantity. Here, we present a washing technique using irrigation system operated with a foot pedal for endoscopic hematoma evacuation.

Objectives: In neuroendovascular therapy, direct puncture of the carotid artery can be a useful method in cases in which the femoral and brachial approaches are infeasible. However, with the puncture method, hemostasis is difficult and postoperative bleeding may cause serious complications. Further, the procedure often requires the use of multiple antithrombotic medications when more effective hemostasis is required. We previously reported the usefulness of direct puncture of the carotid artery upon its exposure. However, controlling the bleeding (oozing) from the soft tissue around the dissected and separated carotid artery is not always successful, creating the risk of subcutaneous hematoma. The hemostasis effect of Floseal (Baxter Healthcare Corporation, Deerfield, IL, USA), an absorbable local hemostatic agent that contains cross-linked gelatin particles and dried human thrombin, was previously reported. Here we used Floseal to close the surgical wounds.

Case and methods: The cases of four patients undergoing carotid artery stent placement or coil embolization using direct carotid artery puncture because of difficulty with other access routes were examined here. Two antiplatelet drugs were used preoperatively, while intravenous heparin was given intraoperatively. After completing stent placement or coil embolization, Floseal was applied on the surface of the separated soft tissue to close the wounds.

Results: No cases of postoperative bleeding were noted.

Conclusion: Floseal controlled oozing from closed wounds despite the patients being under antithrombotic therapy, and no cases of subcutaneous hematoma were noted.