Carotid endarterectomy (CEA) is a well-established surgical technique; however, the use of an internal shunt and approach to high-level lesions vary depending on the surgeon and institution. Here, we describe the surgical position. Appropriate head rotation and mandibular elevation expand the retromandibular space and provide a surgical corridor to expose the distal end of the internal carotid artery. Because this procedure can be performed in the same surgical position and with the same techniques regardless of the plaque location, it could be easier to become proficient by using CEA. By acquiring experience and skills, CEA can be safely performed with an internal shunt even for high cervical lesions.

Background: While the number of treatments available for unruptured cerebral aneurysms in older patients is increasing with increasing population age, the suitability of each new procedure must be carefully considered, given that these are preventive surgeries. We report our analyses of outcomes of surgical treatment for unruptured cerebral aneurysms in older patients at our hospital.

Methods: We investigated the treatment of 66 older patients, comprising 10 cases of craniotomy and 56 cases of endovascular treatment performed surgically at our hospital between January 2006 and August 2023. We assessed age, underlying disease, reason for surgery, aneurysm diameter, location, length of hospital stay, modified Rankin Scale (mRS) scores at admission and discharge, and complications among 66 older patients.

Results: Endovascular treatment was most common among older patients (85% vs. 15%). Patients in the endovascular treatment group were significantly older (76.5±1.6 years vs. 79.9±4.0 years, p=0.010) and had more underlying diseases. Aneurysm diameter was larger in the endovascular treatment group (6.6±2.1 mm vs. 10.1±6.9 mm, p=0.110), and craniotomy was more common for middle and distal anterior cerebral artery aneurysms, while endovascular treatment was more common for internal carotid artery aneurysms and posterior circulation aneurysms (p=0.006). Although length of hospital stay was significantly shorter in the endovascular treatment group (32.3±20.5 days vs. 15.9±7.2 days, p<0.0001), no difference in mRS at admission and discharge was observed. Permanent complications occurred in five patients: one in the craniotomy group (10.0%) and four in the endovascular treatment group (7.1%). Declines in mRS (9 cases) were significantly more frequent in patients aged 78 years or older (p=0.041), with large aneurysms (p<0.0001) and with internal carotid artery (ICA) aneurysms or ICA and posterior communicating artery junction (IC-Pcom) aneurysms (p=0.026). The permanent complication rate was also significantly higher for patients aged 78 years or older (13.2%; p=0.046), with large aneurysms (20.0%; p=0.012) and with ICA or IC-Pcom aneurysms (13.8%; p=0.012).

Conclusions: Surgical treatment for unruptured cerebral aneurysms is useful for older patients. Indications should be carefully considered owing to the increased risk of complications in patients aged 78 years or older, those with large aneurysms, and those with ICA or IC-Pcom artery aneurysms.

We report a case in which an arteriovenous fistula (AVF) persisted despite confirmed obliteration of the nidus following Gamma Knife treatment for a frontal lobe arteriovenous malformation (AVM) and led to progressive enlargement of a venous aneurysm over time, necessitating embolization via endovascular treatment.

A 9-year-old girl presented with headaches. Magnetic resonance imaging (MRI) revealed a left frontal lobe AVM with a maximum diameter of 4 cm, classified as Spetzler-Martin grade 3. Cerebral angiography revealed multiple feeders from the bilateral anterior cerebral arteries supplying the nidus with three distinct draining veins. Gamma Knife treatment was performed, and the disappearance of the nidus was confirmed. However, the AVF remained, and progressively enlarged varices were observed. AVF embolization was performed using a combination of coils and Onyx. The shunt flow was successfully eliminated postoperatively, and the patient was discharged home without any new neurological deficits.

A fistulous component may be present in AVMs with high-flow shunts. In this case, Gamma Knife treatment might have selectively obliterated only the nidus, leading to the manifestation of AVF. However, there is no consensus on the natural course or optimal treatment strategies for such cases. In this patient, rapid enlargement of the venous aneurysm was observed over a short period, and early intervention was performed considering the risk of hemorrhage. In rare cases, individualized treatment planning and meticulous long-term follow-up with detailed imaging assessments are required.

A 52-year-old man presented with an unruptured medium-sized left internal carotid artery (ICA) aneurysm approximately 5 mm in diameter. Implantation of a flow diverter (FD) with an adjunctive coil was planned. Antiplatelet therapy using aspirin and clopidogrel was administered two weeks preoperatively. The patient was suspected to be nonresponsive to clopidogrel based on a platelet aggregation test. Loading and maintenance doses of prasugrel were thus administered in place of clopidogrel. A pipeline flex with shield technology was successfully implanted, and stent wall apposition was good. Postoperatively, an anticoagulant was administered via continuous intravenous infusion for three days. While brain magnetic resonance imaging (MRI) and angiography (MRA) showed positive FD results, the patient developed a sudden-onset disturbance of consciousness, aphasia, and right hemiparesis on postoperative day 4. Brain MRI and MRA revealed an acute left cerebral infarction due to left ICA occlusion. An emergency mechanical thrombectomy for in-stent thrombosis was performed, after which the patient was transferred to a rehabilitation hospital with a modified Rankin scale score of 3. Relationships between parent vessel, aneurysm, and blood flow dynamics should be considered when deciding to perform FD alone or with adjunctive coil embolization for unruptured medium-sized intracranial aneurysms. FD with adjunctive coil embolization for aneurysms of the lesser curvature of the ICA requires particular caution due to the possibility of inducing in-stent thrombosis. Treatment with FD alone is thus recommended. An alternative option is to finish the initial treatment by coil embolization alone and perform FD placement during retreatment.

Herein, we report two cases of delayed cerebral ischemia (DCI) associated with angiographic vasospasm (AVS) that occurred after the completion of clazosentan treatment: one newly developed and one progressive.

Case 1: A female in her 80s (World Federation of Neurosurgical Societies [WFNS] grade 2) underwent coil embolization for a right middle cerebral artery (MCA) bifurcation aneurysm. No AVS or DCI was observed during clazosentan administration (days 3–14). However, on days 17, 19, and 20, AVS/DCI developed in the right MCA, requiring intra-arterial fasudil hydrochloride injections. Dehydration was suspected to be a contributing factor.

Case 2: A female in her 50s (WFNS grade 5) underwent coil embolization for aneurysms in the anterior communicating artery (Acom) and the paraclinoid internal carotid artery. During clazosentan administration, AVS or DCI was observed in the MCA and Acom on day 10. AVS or DCI recurred on day 17 and was treated with intravenous fasudil hydrochloride and increased fluid supplementation.

These cases suggest that careful observation for DCI is required after the completion of clazosentan treatment.

Flow diverter (FD) stents have shown high efficacy in treating large aneurysms; however, their effectiveness in aneurysms involving branching vessels remains uncertain. We report two cases in which FD placement combined with coil embolization successfully treated large ruptured internal carotid-posterior communicating artery (IC-PC) aneurysms.

Case 1: A 72-year-old female presented with headache and was diagnosed with subarachnoid hemorrhage due to a ruptured right IC-PC aneurysm. The aneurysm measured 10 mm with a wide neck, and the posterior communicating artery (Pcom) originated from the aneurysm dome in a nonfetal configuration. Despite initial coil embolization in the acute phase, recanalization was observed after 8 months, leading to combined FD-coil treatment. Angiography performed 12 months later showed Pcom narrowing, complete aneurysm obliteration, and O’Kelly-Marotta (OKM) scale C.

Case 2: A 72-year-old female presented with altered consciousness and was diagnosed with subarachnoid hemorrhage from a ruptured left IC-PC aneurysm. The 13-mm aneurysm had Pcom branching near the neck, with similar P1 and Pcom diameters. Initial coil embolization was performed on the same day, but recanalization occurred after 2 months, prompting a combined FD-coil treatment. While the Pcom was visible on internal carotid artery angiography immediately after treatment, the 10-month follow-up imaging showed complete aneurysm occlusion (OKM scale D) and Pcom disappearance.

We experienced two cases where combined FD-coil treatment was successful in treating ruptured IC-PC aneurysms with recanalization after coil embolization. FD placement is considered an option for large IC-PC aneurysms that are difficult to treat using conventional treatments.

Gamma knife surgery is an established treatment for arteriovenous malformations. Although known long-term complications of this surgery include radiation-induced vascular changes such as cavernous malformations, cysts, and chronic expanding hematomas, the simultaneous development and progression of all three in an adult patient is extremely rare.

We present the case of a 33-year-old man who underwent radiosurgery for a large arteriovenous malformation in the right parietal region, with complete obliteration being confirmed three years post-treatment. Thirteen years later, magnetic resonance imaging (MRI) revealed a small perilesional cyst that remained stable for several years. Twenty-four years after treatment, the patient developed seizures, and imaging demonstrated enlargement of the cyst along with a new mass-like lesion. One year later, the patient experienced progressive left-leg weakness and worsening cerebral edema. Surgical removal was performed due to worsening symptoms. Intraoperative findings revealed a lesion composed of a cavernous malformation, a chronic hematoma, and a cyst. Gross total resection was achieved. Histological examination confirmed the diagnosis of a cavernous malformation. Postoperatively, the patient’s symptoms improved, and he returned to independent daily life.

This case highlights an exceptionally rare report in which all three pathologies were simultaneously identified in an adult patient treated for radiation-induced cavernous malformation. The accumulation of similar reports is crucial for a better understanding of long-term risks and for establishing appropriate surveillance strategies.

We report a case of a dissecting posterior communicating artery aneurysm that was difficult to identify preoperatively as the source of hemorrhage. A 69-year-old male was admitted to our hospital with the complaint of sudden onset of severe headache. Computed tomography angiography (CTA) demonstrated a 2-mm aneurysm at the bifurcation of the right middle cerebral artery (MCA). The hematoma was predominantly distributed on the right side on the CT scan. Cerebral angiography did not reveal any additional source of bleeding. The MCA aneurysm was therefore presumed to be ruptured, and surgical neck clipping was performed.

Intraoperatively, the right MCA aneurysm did not adhere to the surrounding hematoma. Further exploration during hematoma removal revealed a large hematoma around the internal carotid artery (IC) and a thin hematoma adhering to the red vascular wall of the posterior communicating artery (Pcom). Based on these findings, we concluded that the dissecting aneurysm at the Pcom had ruptured. As a penetrating branch was found at the dissection site, direct surgical intervention was deemed difficult, and aneurysm wrapping was performed instead. Postoperative MRI revealed no ischemic changes. The patient eventually recovered with a modified Rankin Scale score of 1. In this case, preoperative imaging failed to accurately identify the bleeding source, and a definitive diagnosis was achieved intraoperatively. The ability to identify the source of bleeding under a microscope is an advantage of craniotomy and is believed to have contributed to the favorable treatment outcomes in this case.