Development of a Model for Plaque Induction in Rat Carotid Arteries.

Objective Plaque induction through intimal injury using a balloon catheter in small animals and by artificial ligation of the carotid artery in large animals have been reported. However, these reports have not yet succeeded in inducing stable plaques nor creating a high degree of intimal thickening to be used as animal models. We have previously developed a plaque induction model in rats but have failed to obtain a plaque incidence frequency that can be used as a model. Thus, in the current study, we aimed to create a versatile disease model to examine the pharmacokinetics of drug administration, determine the efficacy of treatment, and examine the process of intimal thickening. We also attempted to create an improved model with shorter, more frequent, and more severe intimal thickening. Materials and Methods The common carotid artery of male Wistar rats was surgically exposed and completely ligated with a wire and 6-0 nylon thread. Then, the wire was removed to create a partial ligation. To create a high frequency and high degree of intimal thickening, 72 rats were divided into two groups: a single lesion group with a 0.25-mm wire and a single ligature point, and a tandem lesion group with a 0.3-mm wire and two ligature points. Each group was further divided into normal diet and high cholesterol diet groups. The presence and frequency of intimal thickening were examined for each group after 4, 8, and 16 weeks of growth. Results In the single lesion group, intimal thickening was observed in 42% of the 4-week group and 75% of the 8-week group. In the tandem lesion group, intimal thickening was observed in 75% of the 4-week group and 50% of the 8-week group. In addition, 50% of the individuals reared for 16 weeks developed intimal thickening. Conclusion We successfully induced intimal thickening in the carotid arteries of rats with high frequency in the single lesion and tandem lesion groups. The results also showed that the tandem lesion group tended to induce intimal thickening earlier than the single lesion group.

Risk of postoperative scalp necrosis in the occipital artery region after posterior cranial fossa surgery.

Ischemia-induced postoperative scalp necrosis in the superficial temporal artery (STA) region is known to occur after STA-middle cerebral artery anastomoses. However, no reports have evaluated the risk of postoperative scalp necrosis in the occipital artery (OA) region. This study examined the surgical procedures that pose a risk for postoperative scalp necrosis in the OA region following posterior cranial fossa surgery. Patients who underwent initial posterior fossa craniotomy at our institution from 2015 to 2022 were included. Clinical information was collected using medical records. Regarding surgical procedures, we evaluated the incision design and whether a supramuscular scalp flap was prepared. The supramuscular scalp flap was defined as a scalp flap dissected from the sternocleidomastoid and/or splenius capitis muscles. A total of 392 patients were included. Postoperative scalp necrosis occurred in 19 patients (4.8%). There were 296 patients with supramuscular scalp flaps, and supramuscular scalp flaps prepared in all 19 patients with postoperative necrosis. Comparing incision designs among patients with supramuscular scalp flap, a hockey stick-shaped scalp incision caused postoperative necrosis in 14 of 73 patients (19.1%), and the odds of postoperative scalp necrosis were higher with the hockey stick shape than with the retro-auricular C shape (adjusted odds ratio: 12.2, 95% confidence interval: 3.86-38.3, p = 0.00002). In all the cases, ischemia was considered to be the cause of postoperative necrosis. The incidence of postoperative necrosis is particularly high when a hockey stick-shaped scalp incision is combined with a supramuscular scalp flap.

Radiation-induced anterior inferior cerebellar artery pseudoaneurysm after stereotactic radiosurgery for vestibular schwannoma: features observed by direct surgery.

BACKGROUND: In vestibular schwannoma (VS) patients treated with stereotactic radiosurgery (SRS), radiation-induced pseudoaneurysm is a rare long-term complication. To the best of our knowledge, there has been only one report of direct surgery in ruptured cases, and the optimal strategy for direct surgery is yet to be clarified. This case report describes a case of ruptured VS-related SRS-induced pseudoaneurysm that was successfully treated by direct surgery. CASE PRESENTATION: A 57-year -old man underwent SRS for VS, and the tumour was well controlled after the SRS. Nine years after the SRS, however, he developed subarachnoid haemorrhage, and a SRS-induced distal anterior inferior cerebellar artery aneurysm was detected on the surface of the tumour. During the trapping surgery, the aneurysm was embedded in the tumour, and it was difficult to separate the aneurysm and tumour. Besides, the facial nerve and tumour restricted exposure of the parent artery. The parent artery proximal to the aneurysm could only be exposed by resecting caudal part of the tumour. The aneurysm was trapped with permanent clips and it was pathologically diagnosed as pseudoaneurysm. CONCLUSION: It was suggested that the VS-related SRS-induced pseudoaneurysm is tightly adhered with surrounding structures and exposure of the parent artery could be limited due to the tumour and facial nerve. In this case report, we describe detailed intraoperative findings that will be useful for developing strategies for trapping surgery in future.

Evaluating diploic vein blood flow using time-resolved whole-head computed tomography angiography and determining the positional relationship between typical craniotomy approaches and diploic veins in patients with meningioma.

BACKGROUND: Diploic veins may act as collateral venous pathways in cases of meningioma with venous sinus invasion. Diploic vein blood flow should be preoperatively evaluated to consider preserving the veins. In this study, we evaluated the use of time-resolved whole-head computed tomography angiography (4D-CTA)-which is less patient-intensive than digital subtraction angiography (DSA)-for assessing diploic vein blood flow and the positional relationship between typical craniotomy approaches and diploic veins. METHODS: We retrospectively examined 231 patients who underwent surgery for intracranial meningioma. We performed contrast-enhanced magnetic resonance imaging (MRI) to evaluate diploic vein pathways and compared the visualization rates of diploic vein blood flow assessed using 4D-CTA and DSA. Subsequently, we evaluated the rates of the diploic veins transected during craniotomy by comparing the pre- and postoperative contrast-enhanced MRI. RESULTS: The diagnostic performance of 4D-CTA was assessed in 45 patients. Of the 320 diploic veins identified in these patients, blood flow in 70 (21.9%) diploic veins was identified by 4D-CTA and DSA, and both results were consistent. To assess the transection rates of the diploic veins, 150 patients were included. A trend towards a high transection rate of the diploic vein in the basal interhemispheric, frontotemporal, orbitozygomatic, combined transpetrosal, and convexity craniotomy approaches was observed. CONCLUSIONS: In patients with meningiomas, both 4D-CTA and DSA are useful in evaluating diploic vein blood flow. In meningiomas with venous sinus invasion, determining the extent of craniotomy after understanding the pathways and blood flow of diploic veins is recommended.

Diploic veins as collateral venous pathways in patients with dural venous sinus invasion by meningiomas.

BACKGROUND: Although it is known that diploic veins frequently communicate with the dural venous sinuses, the role of diploic veins in patients with venous sinus invasion from meningiomas remains unknown. METHODS: We retrospectively examined the medical records of 159 patients who underwent their first craniotomies for intracranial meningiomas. Contrast-enhanced magnetic resonance imaging was used to evaluate diploic vein routes, and digital subtraction angiography (DSA) was used to evaluate diploic vein blood flow. When high blood flow was visualized concurrently with the venous sinuses, the veins were classified as of the "early type." Diploic vein routes were classified into five routes. RESULTS: DSA was performed in 110 patients, with 14 showing superior sagittal sinus (SSS) invasion (SSS group) and 23 showing non-SSS venous sinus invasion (non-SSS group). The proportion of early type diploic veins was significantly higher in the SSS group (27.1%) than in other patients (patients without venous sinus invasion, 2.1%; non-SSS, 4.3%) (p < 0.01). In patients not in the SSS group, diploic veins were sacrificed during craniotomy in 76 patients, including four patients with veins of the early type. No patients demonstrated new neurological deficits postoperatively. In the SSS group, diploic veins were sacrificed in all patients, and early type diploic veins were cut in five patients. Two of these five patients showed postoperative neurological deficits. CONCLUSIONS: In the SSS group, diploic veins may function as collateral venous pathways, and attention is recommended for their interruption. In patients without SSS invasion, diploic veins, even of the early type, can be sacrificed.

Reduction of thromboembolic complications during the endovascular treatment of unruptured aneurysms by employing a tailored dual antiplatelet regimen using aspirin and prasugrel.

BACKGROUND: Thromboembolic complications (TECs) are frequent during the endovascular treatment of unruptured aneurysms. To prevent TECs, dual antiplatelet therapy using aspirin and clopidogrel is recommended for the perioperative period. In patients with a poor response, clopidogrel is a risk factor for TECs. To prevent TECs, our study assessed the stratified use of prasugrel. METHODS: Patients who underwent endovascular therapy for unruptured cerebral aneurysms from April 2017 to August 2019 were enrolled in this clinical study and given premedication with aspirin and clopidogrel for 2 weeks prior to the procedure. P2Y12 reaction units (PRU) were measured using the VerifyNow assay on the day before the procedure (tailored group). In subgroups with PRU <240, the clopidogrel dose was maintained (CPG subgroup). In subgroups with PRU ≥240, clopidogrel was changed to prasugrel (PSG subgroup). We compared the occurrence of TECs with retrospective consecutive cases from January 2015 to March 2017 without PRU assessments (non-tailored group). The frequency of TECs within 30 days was assessed as the primary endpoint. RESULTS: The tailored and non-tailored groups comprised 167 and 50 patients, respectively. TECs occurred in 11 (6.6%) and 8 (16%) patients in the tailored and non-tailored groups (P=0.048), respectively. The HR for TECs was significantly reduced in the tailored group (HR 0.3, 95% CI 0.11 to 0.81); P=0.017) compared with the non-tailored group. CONCLUSION: The results suggest that tailored dual antiplatelet therapy medication with PRU significantly reduces the frequency of TECs without increasing hemorrhagic complications.

The outcomes of early aneurysm repair in World Federation of Neurosurgical Societies grade V subarachnoid haemorrhage patients with emphasis on those presenting with a Glasgow Coma Scale score of 3.

Grade V subarachnoid haemorrhage (SAH) patients may be dichotomised into those with temporary deterioration and those with irreversible injury, and only the former have a chance of favourable outcomes by aneurysm obliteration. One method of differentiating the two conditions is to wait and observe potential recovery for 12-48hours. However, early rebleeding and non-convulsive seizures may occur during this period. In our institution, grade V SAH patients receive immediate treatment (general anaesthesia induction and aneurysm obliteration within 24hours of onset) to minimise those risks. We focused on therapeutic outcomes in SAH patients presenting with a Glasgow Coma Scale score of 3 (GCS-3). Between January 2006 and December 2013, 82 GCS-3 SAH patients were admitted, among whom 51 (62%) underwent immediate aneurysm obliteration. Their outcomes 90days after onset were evaluated with the Glasgow Outcome Scale, with either good recovery or moderate disability regarded as favourable outcomes. Multivariate logistic regression analysis was performed to identify variables correlated with favourable outcomes. Among the 51 patients, 11 (22%) had favourable 90-day outcomes. Age (odds ratio [OR], 0.838; 95% confidence interval [CI], 0.733-0.959; p=0.010) and intact pupillary light reflex (OR, 21.939; 95% CI, 1.465-328.576; p=0.025) were correlated with favourable outcomes. By contrast, neither intact respiratory pattern nor isocoric pupils was correlated with favourable outcomes. The current results indicate that vigorous intervention may be worth attempting in young GCS-3 SAH patients with intact pupillary light reflex. It remains unclear, however, whether the seemingly high frequency of favourable outcomes was truly due to reduction in early rebleeding or seizures.

Concurrence of Aneurysmal Subarachnoid Hemorrhage and Stanford Type A Acute Aortic Dissection.

We report a rare case of concurrent aneurysmal subarachnoid hemorrhage (SAH) and acute aortic dissection (AAD). A 38-year-old man visited our hospital complaining of severe headache, and brain computed tomography (CT) revealed the presence of SAH. Thoracic to neck computed tomography angiography (CTA), performed in addition to brain CTA, suggested a tear in the aortic arch, and subsequent CT aortography established the diagnosis of Stanford type A AAD. The AAD in our patient, who reported no episodes of chest or back pain, was detected incidentally by thoracic to neck CTA. The imaging study has rarely been indicated for SAH except that it provides additional anatomical information in patients for whom extracranial-intracranial bypass surgery or endovascular treatment is considered. Nevertheless, our experience may highlight additional diagnostic value of thoracic to neck CTA in SAH patients.

Therapeutic outcomes for patients with aneurysmal subarachnoid hemorrhage complicated by Takotsubo cardiomyopathy.

BACKGROUND: There are no guidelines regarding the optimal treatment of subarachnoid hemorrhage (SAH) patients complicated by Takotsubo cardiomyopathy (TCM). Although coiling has been favored as the first-line treatment, clipping may also be indicated in patients with ruptured middle cerebral artery aneurysms or in those with massive intracerebral hemorrhage. The study objective is (1) to report the feasibility/safety of clipping/coiling and (2) to identify possible prognosticators in that population. METHODS: Between January 2008 and December 2014, 371 consecutive patients with aneurysmal SAH underwent transthoracic echocardiography after admission, and 30 with TCM (7.7 %) were identified. We reviewed the incidence and type of perioperative complications among clipped (n = 11) and coiled (n = 19) patients. The 30 patients were dichotomized based on their 90-day modified Rankin scale (mRS) scores into favorable (mRS: 0-2) and unfavorable (mRS: 3-6) groups, and their demographic, laboratory and echocardiographic variables were compared. RESULTS: Neither clipped nor coiled patients developed serious perioperative cardiopulmonary complications, but coiled patients had a higher incidence of fatal procedure-related complications. Among the 30 patients, 13 (43 %) had favorable 90-day outcomes, and the favorable group was significantly younger. Age, but not the degree of cardiac dysfunction, correlated with outcomes by multivariate regression analysis. CONCLUSIONS: Clipping was shown to be a safe treatment modality in our cohort, and treatment selection may better be made on a case-by-case basis in most patients with SAH-induced TCM. The lack of correlation between the degree of cardiac dysfunction and outcomes indicates that aggressive intervention is justified in patients with severely impaired cardiac function.