Introduction: Internal carotid artery-posterior communicating artery aneurysms (ICPCANs) are occasionally located under the anterior petroclinoid fold (tentorium). The tentorium must be resected to achieve safe and secure clipping of the ICPCAN. The surgeon performing the procedure must be careful not to damage the oculomotor nerve, which is usually located behind the aneurysm, to ensure that the patient's oculomotor function is preserved. In this article, we presented a surgical technique for the tentorium resection and oculomotor nerve mobilization during an ICPCAN clipping intervention. Additionally, the clinical features of the patients who underwent the procedure have been described.

Materials and Methods: Five patients who underwent tentorium resection for ICPCAN neck clipping were analyzed. The anterior clinoid process (ACP) was removed in three cases. When the aneurysm was under the tentorium and sufficient space to observe important structures around the aneurysm was lacking, we cut and resected the tentorium to the necessary extent and peeled the oculomotor nerve from the aneurysm. The following factors were analyzed in the five patients: age, sex, direction of the projection of the aneurysm, aneurysm size, position of the aneurysmal neck, degree of aneurysm exposure, whether an anterior clinoidectomy was performed, and presence and extent of oculomotor nerve deficit.

Results: The mean age of the patients was 68.0 years (54-83 years), and all five were female. The mean maximum aneurysm diameter was 6.6 mm (4.7-8.7 mm). The mean neck position of the aneurysms was 0.0 mm (-1.2 to 1.2 mm) superiorly, 2.8 mm (0.7-4.8) posteriorly, and 1.1 mm (-0.8 to 3.6 mm) medially from the tip of the ACP. Inconsistency in the relative position between the aneurysmal neck and ACP made it difficult to predict the need for tentorium resection before the surgery. In two cases, only the neck was exposed, without peeling the oculomotor nerve from the aneurysm, whereas the aneurysm was completely exposed in the other three cases. One of the patients who underwent neck clipping without peeling of the oculomotor nerve from the aneurysm experienced a transient worsening of oculomotor palsy. Two patients who underwent neck clipping with complete peeling of the oculomotor nerve from the aneurysm experienced transient oculomotor palsy and recovered in the 1st and 4th postoperative months, respectively.

Conclusion: We presented a surgical technique for tentorium resection and oculomotor nerve mobilization for ICPCAN clipping, as well as the clinical features of the patients who underwent the intervention. Although it is difficult to predict the need for these procedures preoperatively, the procedures are considered safe and effective for clipping aneurysms completely and preventing oculomotor nerve palsy.

Middle cerebral artery aneurysms (MCANs) associated with short M1 located in the limen insulae tend to have poor outcomes after surgical clipping due to brain contusions and ischemic complications. However, the effect of veins in the deep Sylvian fissure is unclear. The normal variant of the insular veins and deep middle cerebral vein, which runs anteriorly near the limen and drains into the sphenoparietal sinus, is known as the common vertical trunk (CVT). We retrospectively examined whether the presence of a CVT increased surgical complications after clipping of short M1 aneurysms in 164 cases of unruptured MCANs (153 patients) clipped by the same surgeon. The 21 aneurysms located proximal to the limen insulae were defined as short M1 aneurysms. The 164 patients were divided into a short M1 group (n=21) and a non-short M1 group (n=143). The short M1 group was further divided into a CVT group (n=6) and a non-CVT group (n=15). The short M1 group showed a significantly (p＜0.001) longer operative time and higher rates of lacunar infarction and symptomatic (modified Rankin score ≥1) infarction than the non-short M1 group. The CVT group had higher rates of lacunar infarction and symptomatic infarction (50.0% and 16.7%, respectively) than the non-CVT group (26.7% and 6.7%, respectively). The CVT obstructed the view of the aneurysm neck behind the CVT, where the lenticulostriate arteries were located. The presence of a CVT in cases of short M1 aneurysms may be a risk factor for ischemic complications after clipping surgery.

Patients with asymptomatic unruptured intracranial aneurysms (UIA) in the anterior circulation underwent diffusion- and T2-weighted imaging (DWI and T2WI, respectively) 2 days before and 4-5 days after microsurgical clipping. Newly detected lesions on DWI and T2WI after treatment were the primary endpoints of this study. Between 2011 and 2018, 487 patients underwent microsurgical clipping in 512 consecutive procedures for 581 aneurysms. New ischemic lesions were detected on DWI in 48 patients (9.4%): in the territory of arteries adjacent to the aneurysm in 20 patients, in the territory distal to the aneurysm in 20, and in the territory unrelated to the aneurysm in 8. Ischemia of the perforating arteries was observed in 29 patients (5.7%). Size (＞7 mm), the use of temporary occlusion, and no motor-evoked potential (MEP) change were possible risk factors for new ischemic lesions but were not statistically significant. Four (8.3%) of the 48 new ischemic lesions were temporarily symptomatic but fully recovered 6 months after surgery. T2WI detected 144 new lesions in 127 (24.4%) patients, with 80 being approach-related, 14 venous congestion, 48 ischemic, and 2 hemorrhagic. The volume of affected brain ranged from 0.03 to 18.5 mL (mean 1.54). Approach-related, venous congestion, and hemorrhagic lesions were all asymptomatic. All 48 ischemic lesions detected on DWI were also detected on T2WI. Sixty-four of 72 (88.9%) approach-related and 8 of 11 (72.7%) venous congestion lesions were not detected on magnetic resonance imaging (MRI) at the 1-year follow-up. In conclusion, early postoperative MRI is useful for assessing the quality of microsurgery by objectively reflecting surgical invasiveness with high sensitivity.

The long-term neuroradiological prognosis of clip-ligated asymptomatic unruptured cerebral aneurysms is still unknown. Neuroradiological studies with contrast material (computed tomography [CT] angiography and/or digital subtraction angiography) were performed in 272 consecutive patients (283 procedures) with clip-ligated 316 aneurysms at 5 years or later after the procedure to evaluate local recurrence of the target aneurysms. There were 48 aneurysms at the anterior communicating artery (ACoA), 9 at other anterior cerebral arteries, 45 at the posterior communicating artery (PCoA), 64 at other internal carotid arteries, 139 at the middle cerebral artery, and 11 in the posterior circulation. Neck/aneurysm remnant was identified in 19 (6.0%) cases. The most recent imaging was performed at an average of 85.2 months (median, 75 months) after the procedure. Two aneurysms showed local recurrence at 79-113 months after the procedure. The overall annual recurrence rate was 0.15% (Kaplan-Meier) and 0.10% (patient-year). In patients with completely clipped aneurysms, the annual recurrence rate was 0.15% (Kaplan-Meier) and 0.053% (patient-year). In patients with neck remnant, the annual recurrence rate was 1.2% (Kaplan-Meier) and 0.8% (patient-year). This study demonstrates that the incidence of local recurrence of clip-ligated asymptomatic unruptured cerebral aneurysms is very low despite the fact that priority is often given to patency of the normal vessel rather than perfect obliteration of the aneurysm. Although the incidence is very low, local recurrence may take place long after procedures, and continuous monitoring by neuroradiological imaging with contrast material is imperative.

The aim of this study was to clarify the association between the outcomes of patients with subarachnoid hemorrhage (SAH) and various therapeutic risk factors. Endovascular therapy is performed in elderly patients at many institutions as a minimally invasive procedure. However, the appropriate treatment is planned for patients across all age groups at our institution considering the safety aspects of each procedure.

A total of 327 patients were admitted at our institution, between March 2005 and July 2018, due to non-traumatic SAH. Patients with non-aneurysmal SAH, hematoma, and posterior fossa artery dissection, and those who required special procedures such as arterial anastomosis were excluded from the study. Finally, we analyzed 243 patients who underwent surgery for treatment of aneurysmal SAH. Multivariable logistic regression analysis was performed to assess the independent association between the outcomes and certain therapeutic risk factors. Patients were graded on admission based on the World Federation of Neurological Surgeons (WFNS) grading system, and the modified Rankin Scale (mRS) was used to evaluate the outcomes at discharge. The therapeutic risk factors assessed in the multivariable adjustment model were age (at every 5-year interval), sex, method of treatment, WFNS grade (at every 1 grade higher), and shunt dependence (yes/no). The mean age of the patients was 63 years, and 172 patients were women. Only the WFNS grade was associated with the mRS after adjusting for covariates, although there was no association between the mRS and age, except in cases of ruptured aneurysm in the anterior communicating artery.

We concluded that the outcomes at discharge varied based on WFNS grade alone and were not affected by age, except in cases of ruptured aneurysm in the anterior communicating artery.

Background: In metropolitan areas, the ratio of elderly people has been increasing. However, in rural areas it has reached a peak. We analyzed the changes in clinical features and outcomes of subarachnoid hemorrhage (SAH) and discussed the treatment strategy.

Methods: We selected consecutive SAH cases from 2001 to 2005 (Early period, 178 cases) and 2012 to 2016 (Late period, 233 cases). In the Late period, catheter intervention, cilostazol application, and early ambulation were performed. Statistical analyses involving age, Hunt-Kosnik (HK) grade, treatment methods, symptomatic vasospasm, rescue therapy, and treatment outcome were performed.

Results: The median age for both periods was 63 years; however, the ratio of patients over 75 years increased from 17% in the former to 21% in the latter. HK grades 1-3 comprised 81% of cases in both periods. Ratio of clipping/coiling/conservative treatment changed from 79/7.3/14 to 68/17/15, and coiling cases significantly increased (p＜0.05). Post-operative symptomatic vasospasm significantly decreased from 17% to 9%, and balloon angioplasty significantly increased (p＜0.05). Favorable outcome at 30 days did not change significantly (75% vs. 73%).

Conclusions: The ratio of elderly patients increased; however, the SAH outcome was not aggravated by improvement in symptomatic vasospasm treatment and less invasive treatment. Therefore, appropriate arrangement of treatment strategy keeps the SAH outcome favorable in advanced aging society.

Carotid endarterectomy (CEA) is an effective treatment for patients with cervical internal carotid artery stenosis; this has been demonstrated in multiple large clinical trials. We perform CEA for adaptive cases with a unified surgical procedure. In order to avoid ischemic complications associated with carotid artery clamping during surgery, we use an indwelling shunt for almost all cases (routine shunting). In this article, we evaluate the effectiveness and safety of routine shunting retrospectively, focusing on surgical techniques and results at our facility. In 234 patients, 255 CEAs were performed at our facility from April 2012 to March 2018. Among the 255 CEAs, diffusion-weighted imaging (DWI) positive lesions were found in 14 cases (5.5%). However, no symptomatic cerebral infarction was observed. As a result of examination of the complications, 4 cases (1.6%) had symptomatic complications at 30 days after surgery, of which 1 case (0.4%) died. We concluded that CEA with routine shunting yields good surgical results through a unified surgical procedure and careful hemostasis.

Pediatric patients with moyamoya disease frequently exhibit extensive cerebral infarction at the time of initial presentation and even in the early postoperative period. Cerebral infarctions are more frequent in younger patients. Surgical revascularization is the treatment of choice for patients with moyamoya disease. We modified surgical strategies for patients with moyamoya disease to reduce the incidence of postoperative cerebral infarction. Between January 2004 and December 2015, 46 patients (74 hemispheres) with moyamoya disease, aged ＜18 years, were surgically treated at our hospital. Surgical strategy entailed indirect bypass by encephalo-galeo-myo-duro-synangiosis (EGMDS) (3 hemispheres) for the first era, EGMDS and superficial temporal artery-middle cerebral artery (STA-MCA) single anastomosis (67 hemispheres) for the second era, and EGMDS and double STA-MCA anastomosis (4 hemispheres) for the third era. A review of clinical findings and radiological data showed that surgical treatment is effective for patients with moyamoya disease. Direct bypass can reduce the incidence of postoperative cerebral infarction, especially in younger patients. Postoperative cerebral infarctions were observed in 8 patients, all of whom were aged ＜6 years. Of these, 5 infarctions occurred in the ipsilateral hemisphere (6.8%) and 3 in the contralateral hemisphere (4.0%). Postoperative temporary neurological deficit due to hyperperfusion that had completely resolved by the time of discharge was seen in 9 hemispheres. Considering these results, direct bypass can induce immediate improvements in cerebral circulation that are suitable for patients with rapidly progressive moyamoya disease. However, direct bypass is not completely safe for pediatric patients with moyamoya disease because of the resulting changes in postoperative cerebral hemodynamics. To prevent such complications, we recently performed STA-MCA double bypass as an initial treatment for patients with a high risk of cerebral infarction that can increase cerebral perfusion in areas supplied by both the upper and lower trunks of the middle cerebral artery in a balanced manner. The outcome of this strategy was favorable.

Treatment modalities are yet to be established for acute ischemic stroke patients with major intracranial vessel occlusion due to infective endocarditis (IE). A 44-year-old man presented with sudden aphasia and right hemiparesis. Magnetic resonance angiography (MRA) showed a left middle cerebral artery occlusion, and a diagnosis of hyperacute ischemic stroke was made. He had fever and high C reactive protein level. Transthoracic echocardiography detected vegetation; therefore, IE was suspected. The patient was treated with intravenous recombinant tissue plasminogen activator, but neurological symptoms worsened. He then underwent mechanical thrombectomy, with subsequent favorable clinical outcome. Pathological examination of the retrieved thrombus revealed a cluster of gram-positive cocci, which were also detected in blood culture. We therefore recommend mechanical thrombectomy as a first-line treatment option in patients with large-vessel occlusions due to IE.

We report three cancer patients who underwent mechanical thrombectomy for acute ischemic stroke. Although we achieved successful recanalization in all cases, two patients died within three months. The other patient improved after thrombectomy, but she was severely disabled at three month. The outcome of ischemic stroke in cancer patients is poor with high mortality rates if evaluated at three months. This is because patients with terminal cancer are at high risk of stroke. Thrombectomy may improve not only functional outcome but quality of life in the lifetime, even though life expectancy is short.

Cranioplasty is usually performed in patients with previous external decompression for massive cerebral edema accompanied by severe brain hemorrhage or malignant infarction. However, post-operative infection sometimes occurs after the cranioplasty. If an infection occurs, infected bone removal and second cranioplasty is required. In such cases, the second cranioplasty is difficult because of the thin scar from the previous operation and skin atrophy. We report our experience of two cases requiring a third cranioplasty due to repeated cranial bone infections. In these two cases, we could successfully perform cranioplasty with minimum skin incision by peeling back the skin and dura mater using a neuro-endoscope.