Spinal arteriovenous shunts (SAVS) have several subtypes and accurately understanding its pathophysiology and precise diagnosis is required. Collaboration between interventional vascular specialists and direct surgeons is essential for appropriate treatment. Here, we examined the treatment selection and outcomes of 49 cases with 51 lesions of each shunt type treated at our facility. There were dural lesions in 19 cases, epidural lesions in 12 cases, perimedullary lesions in 10 cases, radicular lesions in seven cases, and three other lesions. Treatment comprised direct surgery in 29 cases (65.9%) and endovascular therapy in 15 cases (34.1%). In all direct surgery cases, the endovascular surgeon shared the treatment strategy with the direct surgeon and provided support for intraoperative shunt identification. In the direct surgery group, 26 lesions were successfully cured (89.7%), while in the endovascular therapy group, 13 lesions showed successful closure or effective embolization (86.7%). The perioperative complications were 4.5%, and no persistent symptoms were observed. In SAVS treatment, the endovascular surgeon performed endovascular intervention, provided accurate diagnoses, including appropriate strategies, such as direct surgery, and offered intraoperative support. This collaborative approach facilitated effective SAVS treatment.

Revascularization for symptomatic common carotid artery occlusion (CCAO) is advisable if hemodynamic ischemia symptoms are observed; however, there are no standardized treatment strategies because hemodynamic status varies in cases. We report the case of a 78-year-old patient with CCAO who presented with transient ischemic attack symptoms comprising right hemiparesis and aphasia and was treated with superficial temporal artery-middle cerebral artery (STA-MCA) bypass after carotid endarterectomy (CEA). Magnetic resonance imaging and angiography revealed occlusion of the left internal carotid artery (ICA) and multiple cerebral infarctions. Carotid ultrasonography, 3DCT angiography, and cerebral angiography indicated CCAO immediately before the carotid artery bifurcation. Additionally, the ICA was occluded to the petrous portion, while the external carotid artery (ECA) was opened from its origin via anastomosis with the vertebral artery. Moreover, N-isopropyl-p-[123I]iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) revealed decreased cerebral blood flow while resting, and revascularization was planned to prevent recurrent ischemia. CCAO-ICA was long; therefore, restoration of antegrade intracranial blood flow was difficult. However, CCAO-ECA was short, indicating that the CEA was suitable for opening the ECA antegrade blood flow. An STA-MCA bypass was performed after CEA to open the CCAO-ECA. SPECT revealed improved postoperative cerebral blood flow while resting, and ischemic symptoms disappeared. In CCAO cases, as in the present case, combined CEA and STA-MCA bypass, which is a conventional technique, may prevent recurrent ischemia.

Cyst formation as a late complication of gamma knife surgery for cerebral arteriovenous malformations (AVM) is well-known; however, angiomatous lesions are rare. We report a case in which angiomatous lesion resection was effective. The patient is a 41-year-old man who underwent gamma knife surgery for parasplenial AVM in his 20s. During follow-up, cysts appeared in the bilateral parietal lobes and repeated convulsion occurred. The patient was referred to our hospital because of prolonged loss of consciousness due to convulsions. Magnetic resonance imaging (MRI) showed an angiomatous lesion and multiple cysts with extensive cerebral edema. Cyst-peritoneal shunt was performed, but consciousness did not improve. Tumor resection was performed. The pathological diagnosis was cavernous hemangioma. Postoperatively, consciousness improved. Asymptomatic cases can be followed. However, in cases with symptomatic hemangioma lesions, prompt surgical removal should be considered.

A 37-year-old man was admitted to our institution for epistaxis after the additional radiotherapy for recurrent nasopharyngeal carcinoma. We embolized the feeding branches of the left artery with 33% n-butyl-2-cyanoacrylate(NBCA). About 30 minutes later, a subsequent massive epistaxis caused respiratory arrest and hemorrhagic shock. After we performed an emergency tracheostomy, the angiogram revealed a pseudo-aneurysm at the pyramidal segment of the left internal carotid artery (ICA). We determined that the collateral circulation was adequate, and performed parent artery occlusion of the left ICA including the aneurysm with 14 coils. Finally we injected 50% NBCA from inside the coils to the proximal ICA to occlude the parent artery completely. Two months later, we detected see-through coil masses in the left ICA in the nasal cavity, but no recurrence of epistaxis. We believe that NBCA injection may aid parent artery occlusion when treating a pseudo-aneurysm.

Here, we report a case of staged carotid endarterectomy (CEA) for a double-lumen carotid plaque. An 81-year-old male with right cervical internal carotid artery (ICA) stenosis, which had been clinically treated, was referred to our department because of progressing left limb shaking. Magnetic resonance angiography (MRA) showed progression of ICA stenosis, and arterial spin labeling (ASL) showed a severe delay in blood flow in the right hemisphere. Diffusion weighted imaging (DWI) did not reveal acute infarction. Cerebral angiography revealed that the right ICA had a dual origin and merged into a single lumen, which, together with the MRI findings, suggested a double-lumen carotid plaque. After the two lumens joined, the ICA formed its narrowest part and then returned to its normal diameter. The narrowest part was NASCET 80% stenosis with severe flow restriction without collateral circulation via the circle of Willis. Due to concerns about hyperperfusion syndrome (HPS), percutaneous transluminal angioplasty (PTA) was performed first. ASL was performed on the day after PTA showed increased blood flow in the right hemisphere without any symptoms. CEA was preferred over carotid artery stenting (CAS) because of the irregular and symptomatic plaques. CEA was performed 2 weeks after PTA. Postoperatively, the patient did not have HPS or any ischemic complications. left limb shaking disappeared, and he was discharged without neurological deficits.

Double-lumen carotid plaques are rare, and their surgical indications and appropriate revascularization methods remain to be elucidated. However, symptomatic double-lumen carotid plaques require surgical treatment. A staged CAS strategy was established to avoid HPS. Generally, the second stage of treatment is CAS. However, according to these guidelines, CEA is preferred over CAS for symptomatic cervical ICA stenosis preferred CEA over CAS especially for vulnerable and irregular plaques, as in this case.

A superficial temporal artery (STA)-middle cerebral artery (MCA) double bypass is performed using two STA branches (frontal and parietal); however, one branch may be absent. We report a case of STA-MCA double bypass using one STA branch. A 67-year-old woman presented with right hemiparesis and motor aphasia secondary to left M1 occlusion. Despite optimal medical therapy, the neurological symptoms worsened after admission. IMP-single photon emission computed tomography revealed reduced cerebral blood flow in the left MCA. STA-MCA double bypass was planned; however, the STA showed only a parietal branch, and double bypass was attempted using only the parietal branch. Following parietal branch harvest, the vessel was divided into two segments. We performed STA-STA anastomosis (end-to-side) and created a Y-shaped donor graft (grafting bypass). Each end was anastomosed (end-to-side) to an MCA branch on the frontal and temporal lobes. The patient showed no new neurological deficit postoperatively. Postoperative magnetic resonance imaging and angiography revealed no ischemic lesion and good bypass patency. This method involves creation of end-to-side anastomoses in all cases, which is a significant advantage of this approach. Most bypass procedures include end-to-side anastomosis, and many neurosurgeons are familiar with this technique. This method may be useful in patients with a single STA branch.

Background: A dural arteriovenous fistula (dAVF) with cortical reflux into the posterior fossa via the superior petrosal vein poses a risk of brainstem and cerebellar hemorrhage. Minimally invasive endovascular surgery and radiotherapy are preferred in several situations over open surgery. Even when these treatments are not curative, direct interruption of the superior petrosal vein remains useful, especially when it is the sole drainage route.

Case 1: A 69-year-old man presented with a gait disturbance. Upon examination, a left-sided tentorial dAVF fed by the tentorial artery was observed to reflux into the pontine vein via the superior petrosal vein, causing regurgitation into the anterior spinal vein and edematous changes in the brainstem. Transarterial embolization of the tentorial artery and gamma knife radiosurgery were not curative. Therefore, we performed direct surgery to block the superior petrosal vein, resulting in the disappearance of the dAVF.

Case 2: A 70-year-old woman presented with a subcortical cerebral hemorrhage. We performed transarterial embolization during the acute phase and transvenous sinus occlusion during the chronic phase. Inadequate embolization of the superior petrosal sinus resulted in residual regurgitation of the cerebellar cortical veins via the superior petrosal vein. As additional transarterial embolization was not curative, direct surgical interruption of the superior petrosal vein was performed, and the dAVF disappeared.

Conclusion: We report two cases of dAVF that were successfully treated by direct interruption of the superior petrosal vein without complications following unsuccessful endovascular embolization. Further case series are needed to determine the safety of this approach in dAVF.

Carotid web (CW) is a fibrous hyperplasia of the intima confined to the carotid bulb, which often causes cerebral infarction and is refractory to medical treatment. Effective medical therapies should be explored. We report a case in which histopathological investigation of thrombus formation was performed for in situ CW and distal embolus. A man in his 40s was admitted to our hospital with an acute right M2 occlusion. Complete recanalization was achieved through mechanical thrombectomy. A thrombus is a combination of platelets, erythrocytes, and fibrin. There was a small CW-like angiographic finding; however, dual antiplatelet therapy (DAPT) with 100-mg aspirin and 75-mg clopidogrel was administered without recurrence. Carotid ultrasonography revealed thrombosis in the CW that decreased gradually. Because no potential embolic source was found on extensive cardiac examination, CW was considered as the cause of the embolism, and carotid endarterectomy (CEA) was successfully performed 3 months after onset. Histopathological examination of the resected CW revealed a platelet-rich thrombus in the recess. We speculated that the mixed thrombus causing the M2 embolism was the secondary thrombus formed on an in situ platelet-rich CW thrombus. Although antiplatelet therapy may have been effective in reducing the formation of the secondary mixed thrombus in this case, further cases and supporting evidence are needed.

Carotid endarterectomy (CEA) for radiation-induced carotid artery stenosis (RI-CS) is considered a high-risk procedure because of its perioperative complications. Carotid artery stenting (CAS) seemingly offers an alternative treatment. However, mid- and long-term outcomes after CAS are not necessarily favorable, and several reports have indicated that CAS has a relatively higher rate of restenosis and additional treatment than those associated with CEA. Herein, we describe a case of RI-CS with repeated in-stent plaque protrusion (ISPP) after CAS. A 74-year-old man was diagnosed with RI-CS one year prior and had undergone CAS for severe stenosis of the left common carotid artery. In-stent stenosis and mobile plaque were detected one year after CAS, necessitating stent-in-stent placement. However, ISPP was repeated over a short period and required additional treatment. In conclusion, RI-CS with a large number of unstable plaques and ulcerations may cause ISPP and cerebrovascular events. Therefore, CEA should be considered as a therapeutic modality.

Occasionally, distal flow-related aneurysm (FA) with hemorrhagic arteriovenous malformation (AVM) showed spontaneous thrombosis. We describe distal FA recanalization after spontaneous thrombosis in the distant period. A 33-year-old woman had intracranial hemorrhage at the right basal ganglia with intraventricular hemorrhage. Computed tomography angiography demonstrated distal FA associated with AVM in the hematoma cavity, which was considered the hemorrhage source. The distal FA showed spontaneous thrombosis in the acute phase, and no recanalization was observed approximately 2 months after onset. After 20-month conservative management, distal FA showed recanalization and target embolization was performed following gamma knife radiosurgery for the nidus. Since distal FA may show recanalization in the distant period after the spontaneous thrombosis as in our case, continuous radiological follow-up is necessary.

The presigmoid posterior transpetrosal approach can allow better multidirectional access to skull base lesions. A wide surgical field extending above and below the tentorium is created through the tentorial incision. To date, this method has been useful in 4 cases of paramedian vascular lesions (2 cases of aneurysm, 1 case of cerebellar arteriovenous malformation, and 1 case of cerebellar hemangioblastoma) at our hospital. The feeder and proximal artery in the deep part of the lesion, and the drainer and distal artery in the superficial part, can be viewed directly in a wide surgical field. By determining the bone removal range for each individual case, drilling-related complications can be reduced and the operation time can be shortened.