Ruptured distal posterior inferior cerebellar artery (PICA) aneurysms are rare, and their underlying clinical features and optimal treatment management are poorly understood. This report thus describes the treatment strategy and outcome of six cases of ruptured distal PICA aneurysms. We treated ruptured distal PICA aneurysms with strategies that preserve the PICA either directly or using a bypass. Since 1998, we have treated six cases of acute ruptured distal PICA aneurysms, comprising one male and five females (mean age at presentation, 49.3 years). The five saccular and one fusiform aneurysm were located at the anterior medullary segment (one case), lateral medullary segment (one case), tonsillomedullary segment (two cases), and telovelotonsillar segment (two cases). The treatment strategies included aneurysmal clipping (two cases), coil embolization (two cases), trapping with an occipital artery-PICA bypass (one case), and an excised aneurysm with an end-to-end PICA bypass (one case). Overall, the outcome at hospital discharge was recovery in five cases and death in one case. No cases of cerebral aneurysm recanalized occurred after treatment during follow-up. These results suggest that our treatment strategies to preserve the PICA vascular territory yield good outcomes, particularly in patients with good clinical grades.

Spontaneous cervical internal carotid arterial dissection (SCICAD) is a common cause of ischemic stroke in younger patients (age ＜50 years). However, the underlying mechanism and pathophysiology are not fully understood, and a standard criterion for the treatment has not been established; therefore, we reviewed seven cases of SCICAD treated between 2013 and 2018 to determine the appropriate treatment. Headaches, orbital pain, or neck pain occurred in six cases. Six patients with SCICAD had an acceptable clinical course with medical therapy alone. Carotid artery stenting (CAS) was performed for three lesions in three patients. One patient was treated with CAS and superficial temporal artery-middle cerebral artery (STA-MCA) bypass. Another patient was treated with CAS with endovascular mechanical thrombectomy. A favorable functional outcome was observed in all cases, and antithrombotic therapy with an anticoagulant or antiplatelet drug was essential. Most patients are successfully treated with low recurrence rates; however, endovascular treatment is a viable option for drug-resistant cases.

Introduction: Middle cerebral artery aneurysms (MCAN) often require multiple clips to achieve occlusion because of their complex shape. For neck clipping in MCAN, combination clip techniques for occlusion with closure lines have been reported to be useful by Ishikawa et al. These combination clip techniques with closure lines are thought to be ideal, but can be difficult to perform due to factors such as neck sclerosis, limited direction of clip insertion, and small aneurysm size. In this study, we report a surgical strategy for MCAN neck clipping with consideration of the closure line and analyze the actual clip selection.

Materials and Methods: Thirty-one consecutive MCAN patients treated with neck clipping with consideration of the closure line by the first author were analyzed. Age, sex, ruptured/unruptured aneurysm, maximum diameter, and complications were investigated. We reviewed the operation records and intraoperative videos, and retrospectively investigated intraoperative ruptures, number of clips, clip shape, and occlusions with or without closure lines. We further analyzed the relationship between these factors and age, sex, ruptured/unruptured aneurysm, and maximum diameter.

Results: The mean age was 63.5 (34-80) years. Twenty-six (83.9%) aneurysms were in female patients, and 3 (9.7%) were ruptured aneurysms. There were no cases of premature intraoperative rupture. Two patients experienced chronic subdural hematoma after clipping surgery, with no other complications. The mean maximum aneurysm diameter was 5.1 mm (2.0-10.2 mm). One clip was applied for 13 aneurysms, two clips for 17 aneurysms, and three clips for one aneurysm. Twenty-four aneurysms (77.4%) were obliterated using a closure line. The aneurysms clipped with two or more clips were significantly larger than those clipped with one clip (5.2 vs. 4.3 mm, p = 0.037). The aneurysms clipped with fenestrated clips were also significantly larger than those clipped without fenestrated clips (6.6 vs. 4.8 mm, p = 0.034). There was no significant difference between aneurysms clipped with and without the closure line in regard to any of the factors. The reasons for not obliterating the closure line were as follows: (1) sclerosis at the aneurysmal neck in two cases, (2) M2 kinking by clip in two cases, (3) limitation of the clip insertion direction in two cases, and (4) the aneurysm was too small in one case.

Conclusion: Combination clip techniques were used to facilitate MCAN clipping of larger aneurysms. The availability of a closure line to obliterate the aneurysm was not associated with aneurysm size, and obliteration with the closure line was achieved at a high rate of 77.4%. The difficulty in obliteration of MCAN with the closure line was due to neck sclerosis, M2 kinking, limited direction of clip insertion, and small size.

Recent developments in cerebral angiography equipment and workstations have made it possible to produce clear angiograms and useful images for neurosurgery. At our institution, we routinely perform cerebral aneurysm clipping after presurgical simulation using imaging data obtained using three-dimensional cerebral angiography. This report describes the clinical significance of three-dimensional cerebral angiography in cerebral aneurysm clipping.

Materials and Methods: Three-dimensional rotational angiography (3D-RA) and three-dimensional rotational venography (3D-RV) were performed on cerebral angiography, and the resulting imaging data were processed on a workstation. Depending on the requirements of each case, we created 3D-RA, 3D-RV, slab maximum intensity projection, and fusion images for presurgical simulation, followed by cerebral aneurysm clipping.

Results: Thirty patients underwent cerebral unruptured aneurysm clipping using this technique. Clipping was completed in all cases. The treatment complications were symptomatic cerebral infarction in one (3%) patient and deterioration in modified Rankin Scale score (≥2) at discharge compared to the preoperative scores in two (7%) patients. No cerebral contusions were observed.

Conclusion: Cerebral angiography images were processed using a workstation for presurgical simulation. We were able to recognize the perforators and microvessels surrounding the aneurysm, cortical vein structure, and positioning of the existing coils in detail. This technique is useful for the presurgical simulation of cerebral aneurysm clipping.

Reportedly, tentative clipping is useful for middle cerebral artery aneurysms; however, the procedure may precipitate intraoperative rupture of aneurysms secondary to incomplete closure of the aneurysm. Between 2013 and 2019, 42 patients with middle cerebral artery aneurysms underwent direct neck clipping using our novel strategy to avoid tentative clipping. Full exposure of the aneurysm effectively avoided excessive tentative clipping. We describe the technical details for dissection between an aneurysm and the surrounding structures, such as vessels, the brain, and a hematoma, under appropriate use of temporary clipping.

Endoscopic evacuation of intracerebral hemorrhage has been gradually recognized as an effective treatment in terms of its minimal invasiveness and safety. Here, we summarize the initial experience of endoscopic intracerebral hematoma evacuation in Saiseikai Kumamoto Hospital between July 2016 and September 2018. Out of 34 consecutive patients, 17 cases were putaminal hemorrhage, 14 cases were subcortical hemorrhage, and 3 cases were cerebellar hemorrhage. Our surgical indications were mainly for lifesaving. While the median hematoma evacuation rate was satisfactory at all hematoma localizations, cases with a hematoma removal rate of 70% or less were especially seen in the putaminal hemorrhage group. In addition, surgical complications (intra/post-operative bleeding) tended to occur in putaminal hemorrhage in the initial experience. To avoid pitfalls and perform surgery safely and reliably, it is necessary to raise the learning curve with experienced operators, referring to the precautions reported so far.

Objective: Normal perfusion pressure breakthrough (NPPB) and occlusive hyperemia (OH) have been reported to cause bleeding and cerebral edema after resection of cerebral arteriovenous malformation (AVM). However, much is unknown regarding the mechanism of these events. Additionally, they do not always coincide with the Spetzler–Martin AVM Grading Scale. In this study, we examined the relationship between the changes in intraoperative angiography (IOA) and single photon emission computed tomography (SPECT) findings, and the risk of developing NPPB and OH.

Materials and methods: From December 2016 to October 2018 in our hospital, 11 patients underwent AVM resection using intraoperative cerebral angiography (IOA). There were six unruptured AVM cases and five ruptured ones, where the average nidus size was 20.8 mm and the average number of draining veins was 1.9. During surgery, complete resection was confirmed using IOA, and postoperative blood pressure was strictly monitored and controlled. If NPPB or OH was suspected on SPECT the day following the surgery, strict blood pressure management was performed.

Results: Unruptured lesions in three cases and ruptured lesions in one case showed significant findings on SPECT. In these cases, stagnation of the contrast agent was observed at the end of the IOA feeders. There were no bleeding complications in patients with suspected NPPB or OH, and cases did not worsen when compared to the preoperative (mRS).

Conclusion: Stagnation of the contrast agent at the end of the IOA feeders is effective basis for assessing the risk of NPPB and OH. This is particularly useful for postoperative management, especially for reducing postoperative complications.

We report a case of subarachnoid hemorrhage in a 66-year-old man. A 3-mm aneurysm of the long circumflex branch of the P1 segment of the posterior cerebral artery was revealed by computed tomography angiography, and this was recognized as the bleeding source based on the hematoma distribution. In addition, the aneurysm was diagnosed as a flow-related aneurysm because the long circumflex branch was the main feeder of the tentorial dural arteriovenous fistula (dAVF). It was considered ideal to prevent re-rupture of the aneurysm and to treat the tentorial dAVF with simultaneous drainage occlusion by endovascular treatment. However, considering the shape of the aneurysm, preservation of the parent artery seemed to be difficult with endovascular treatment; therefore, only the ruptured aneurysm was treated by clipping first and then the tentorial dAVF was treated with endovascular treatment. The patient had a good clinical course without any complications. This case may be helpful in determining the ideal treatment in similar cases.

Paraclinoid aneurysms arise from the ophthalmic segment of the carotid artery, which contributes to a higher rate of surgical complications, including visual impairment, than that seen in other aneurysms. To avoid these complications, we treated three cases of paraclinoid superior hypophyseal aneurysms with a contralateral pterional approach. With this approach, a clinoidectomy was not necessary, and the relationship between the carotid artery, superior hypophyseal artery, and aneurysm was easily identified. Thus, clipping was easily performed without any complication, including visual deficit. Contralateral pterional clipping approach for a small paraclinoid aneurysm can be a useful technique for decreasing its surgical complications, although the surgical indications are limited.

Superficial temporal artery - middle cerebral artery (STA-MCA) bypass surgery is an essential part in the armamentarium of cerebrovascular surgeons. More importantly, it is useful for neurological conditions, such as cerebral ischemia, untreatable cerebral aneurysm, and Moyamoya disease. Although methods and techniques of bypass surgery are widely reported, this is the first report that describes the method of examining the intima at the suture sites, as well as the suturing technique. We performed 112 bypass surgeries (with 207 anastomoses) between May 2012 and April 2018, with a patency rate of 98.1%. Our use of forceps and needle manipulation to perform intimal and needle tail checks, as well as our performance of intimal fitting using a modified suture method, have enabled us to achieve more reliable vascular anastomoses.

Sufficient dissection of the Sylvian fissure is essential to safely clip unruptured cerebral aneurysms. Here, we report a method to dissect the Sylvian fissure, paying particular attention to retraction with the suction instrument. It is important to pay attention to the strength and direction (vector) of the suction instrument when retracting the brain. By using the suction instrument to retract the brain with the appropriate strength and direction (appropriate vector), the visibility of the arachnoid membrane and minute blood vessels is enhanced, allowing safe dissection of the arachnoid, and minimizing brain damage. We believe that sufficient dissection of the Sylvian fissure creates a wide operative field, and consequently facilitates the clipping operation of unruptured cerebral aneurysms.