Spontaneous occlusion of ruptured microaneurysm formed on postoperative transosseous anastomosis after indirect revascularization in a patient with moyamoya disease.

A 40-year-old female with a history of ischemic moyamoya disease treated with indirect revascularization at ages 12 and 25 years presented with a sudden severe headache. Imaging studies revealed focal parenchymal hemorrhage and acute subdural hematoma, confirming a microaneurysm formed on the postoperative transosseous vascular network as the source of bleeding. Conservative management was performed, and no hemorrhage recurred during the 6-month follow-up period. Interestingly, follow-up imaging revealed spontaneous occlusion of the microaneurysm. However, due to the rarity of this presentation, the efficacy of conservative treatment remains unclear. Further research on similar cases is warranted.

Occipital artery to vertebral artery bypass for treatment of bilateral vertebral artery occlusion with QMRA as an adjunct to diagnostic assessment.

PURPOSE: Stroke, the second leading cause of death globally, often involves ischemia in the vertebrobasilar territory. This condition is underexplored, despite significant morbidity and mortality risks. The purpose of this study is to present a case of occipital artery to V3 segment vertebral artery bypass, emphasizing the role of quantitative magnetic resonance angiography (qMRA) in assessing flow and guiding surgical intervention. METHODS: A 66-year-old man with bilateral vertebral artery occlusion presented acute symptoms. qMRA was employed to evaluate flow dynamics and determine the feasibility of a flow augmentation bypass surgery. The occipital artery to left vertebral artery bypass (OA-to-VA) was performed, utilizing an inverted hockey-stick incision and an antegrade inside-out technique. The patency of the bypass was confirmed using both Doppler probe and Indocyanine green. RESULTS: Postoperative assessments, including computed tomography angiography (CTA) and qMRA, demonstrated the patency of the bypass with improved flow in the basilar artery and left vertebral artery. The patient's condition remained stable postoperatively, with residual peripheral palsy of the left facial nerve. CONCLUSION: In conclusion, the presented case illustrates the efficacy of the OA-to-VA bypass in addressing symptomatic bilateral vertebral artery occlusion. The study underscores the pivotal role of qMRA in pre- and postoperative assessments, providing noninvasive flow quantification for diagnostic considerations and long-term follow-up in patients with vertebrobasilar insufficiency.

[Imaging risk factors for postoperative cerebral infarction in adults with ischemic Moyamoya disease].

Objective: To investigate the imaging factors associated with postoperative cerebral infarction in adult patients aged 18 and above with ischemic Moyamoya disease. Methods: The clinical data of adult patients who underwent surgeries for ischemic Moyamoya disease in the Department of Neurosurgery at Peking University International Hospital from October 2015 to October 2020 were retrospectively analyzed. Of the 239 patients, 120 were male and 119 were female, with ages ranging from 18 to 63 (41.7±10.3) years. A total of 239 patients(290 cases) underwent direct and indirect combined revascularization (CR).Gender, age, surgical side, preoperative transient ischemic attack (TIA), presence of old cerebral infarction, and imaging features were compared between the patients with (48 cases) and without (242 cases) cerebral infarction within 1 week after surgery. Multivariate logistic binary regression model was used to analyze the imaging risk factors of postoperative cerebral infarction. Results: Cerebral infarction occurred in 48 cases(16.5%) among the 290 CR group within 1 week after surgery. The proportion of patients with TIA, old cerebral infarction, ICA stenosis, A1 segment stenosis, M1 segment stenosis, abnormal posterior cerebral artery (PCA), and unstable compensation before CR in the cerebral infarction group was higher than that in the non-cerebral infarction group (P<0.05).Preoperative TIA (OR=4.514, 95%CI: 1.920-10.611), old cerebral infarction (OR=2.856,95%CI:1.176-6.936), A1 stenosis (OR=7.027,95%CI:1.877-26.308), M1 stenosis (OR=6.968,95%CI:2.162-22.459), abnormal PCA (OR=4.114,95%CI:1.330-12.728)and unstable compensation (OR=4.488,95%CI:1.194-16.865) were risk factors for cerebral infarction after CR surgery (all P<0.05). Conclusion: Among the imaging factors, TIA, old cerebral infarction, A1 stenosis, M1 stenosis, abnormal PCA and unstable compensation were risk factors for cerebral infarction in adult patients with ischemic Moyamoya disease treated by combined revascularization.

Effect of revascularization surgery on cerebral hemodynamics in adult moyamoya disease.

OBJECTIVE: Few studies have reported local hemodynamic changes after revascularization surgery. This study aimed to identify regional hemodynamic changes after combined revascularization surgery for moyamoya disease using single-photon emission computed tomography with N-isopropyl-p-123I-iodoamphetamine. METHODS: A total of 46 adults with moyamoya disease who underwent combined revascularization surgery from August 2009 to July 2021 at our facility were enrolled. The combined bypass procedure comprised a single direct bypass to the motor area and encephalo-duro-arterio-myo-synangiosis. The preoperative and postoperative cerebral blood flow (CBF) and cerebral vascular reserve (CVR) in the genu; precentral, central, parietal, angular, temporal, and posterior regions; splenium; hippocampus; and cerebellum were measured. To modify the examination variability, the cerebral-to-cerebellar activity ratio (CCR) was calculated by dividing the counts in the region by those in the cerebellum (CBF-CCR and CVR-CCR). RESULTS: Postoperatively, asymptomatic cerebral infarction occurred in three (6.5%) patients. The CBF-CCR and CVR-CCR improved in the precentral, parietal, and temporal regions and in the overall middle cerebral artery (MCA) territory. Sub-analysis of anterior cerebral artery (ACA) and posterior cerebral artery (PCA) territory hemodynamics revealed that patients with normal preoperative hemodynamics showed no changes in the CBF-CCR and CVR-CCR postoperatively, whereas patients with preoperative perfusion impairment exhibited improved CVR-CCR in the ACA territory (0.13-0.3, p=0.019) and CBF-CCR in the PCA territory (0.93-0.96, p=0.0039). CONCLUSION: Combined revascularization surgery with single bypass to the motor area improved hemodynamics in the primary targeted MCA territory and in the ACA and PCA territories among patients with preoperative hemodynamic impairment.

Nonalcoholic fatty liver disease is an independent risk factor for ischemic stroke after revascularization in patients with Moyamoya disease: a prospective cohort study.

BACKGROUND: The study aimed to investigate the association between nonalcoholic fatty liver disease (NAFLD) and ischemic stroke events after revascularization in patients with Moyamoya disease (MMD). METHODS: This study prospectively enrolled 275 MMD patients from September 2020 to December 2021. Patients with alcoholism and other liver diseases were excluded. NAFLD was confirmed by CT imaging or abdominal ultrasonography. Stroke events and modified Rankin Scale (mRS) scores at the latest follow-up were compared between the two groups. RESULTS: A total of 275 patients were enrolled in the study, among which 65 were diagnosed with NAFLD. Univariate logistic regression analysis showed that NAFLD (P = 0.029) was related to stroke events. Multivariate logistic regression analysis showed that NAFLD is a predictor of postoperative stroke in MMD patients (OR = 27.145, 95% CI = 2.031-362.81, P = 0.013). Kaplan-Meier analysis showed that compared with MMD patients with NAFLD, patients in the control group had a longer stroke-free time (P = 0.004). Univariate Cox analysis showed that NAFLD (P = 0.016) was associated with ischemic stroke during follow-up in patients with MMD. Multivariate Cox analysis showed that NAFLD was an independent risk factor for stroke in patients with MMD (HR = 10.815, 95% CI = 1.259-92.881, P = 0.030). Furthermore, fewer patients in the NAFLD group had good neurologic status (mRS score ≤ 2) than the control group (P = 0.005). CONCLUSION: NAFLD was an independent risk factor for stroke in patients with MMD after revascularization and worse neurological function outcomes.

Risk Factors for Specific Postoperative Ischemic Complications in Patients with Moyamoya Disease: A Single-Center Retrospective Study.

AIM: To evaluate and compare postoperative ischemic complications to determine the risk factors for ischemic complications following revascularization surgery for Moyamoya disease (MMD). MATERIAL AND METHODS: This single-center retrospective study included 266 procedures between 2016 and 2021. Three types of revascularization approaches including direct bypass, indirect bypass, and combined bypass were performed. To identify risk factors for postoperative ischemic complications and contralateral cerebral infarction, preoperative clinical characteristics and radiographic features were examined using multivariate and ordinal logistic regression analyses. RESULTS: Postoperative ischemic complications occurred in 103 (6.6%) procedures. Ischemic presentation (p=0.001, odds ratios [OR] 5.59, 95% confidence interval [CI] 2.05-15.23), hypertension (p=0.030, OR 2.75, 95%CI 1.11- 6.83), advanced Suzuki stage (p=0.006, OR 3.19, 95%CI 1.40-7.26), and collateral circulation (p=0.001 OR 0.17, 95%CI 0.06-0.47) were risk factors for postoperative ischemic complications. Ordinal regression analysis revealed that unilateral involvement (p=0.043, OR 2.70, 95%CI 0.09-5.31), hemorrhagic presentation (p=0.013, OR 3.45, 95%CI 0.72-6.18), surgical approach (p=0.032, OR -1.38, 95%CI -2.65, -0.12), and collateral circulation [p=0.043, OR -1 .27, 95%CI -2.51, -0.04)] were associated with the type of ischemic complications. History of hypertension (p=0.031) and contralateral computed tomography (CT) perfusion stage (p=0.045) were associated with contralateral infarction. CONCLUSION: Inability of cerebral vessels to withstand changes in blood pressure induced by revascularization-related hemodynamic instability might be associated with postoperative complications in patients with Moyamoya disease.

Development of the external carotid artery system including the middle temporal artery after direct-indirect revascularization surgery for moyamoya disease.

BACKGROUND: The aim of this study was to clarify when and from which blood vessels indirect revascularization develops after combined revascularization surgery for moyamoya disease and how the donor vessels that undergo direct revascularization change in the medium to long term. In particular, we focused on the middle temporal artery (MTA), which has not received much attention in indirect revascularization surgery for moyamoya disease until now. METHODS: We targeted 20 sides that were suitable for evaluating the diameter of the external carotid artery system involved in combined revascularization surgery among moyamoya disease patients who underwent a composite revascularization procedure utilizing a 'U'-shaped skin incision encircling the parietal branch of the superficial temporal artery (STA) at our institution from 2018 to 2023. We identified the STA parietal branch, MMA, DTA, and MTA in the TOF source MR images acquired preoperatively and three and six months after surgery; measured the long and short diameters of each blood vessel; approximated the blood vessel shape as an ellipse, and calculated its cross-sectional area. RESULTS: The cross-sectional areas of the MMA, DTA, and MTA involved in indirect revascularization significantly increased compared to presurgery three months after surgery, and this trend continued six months after surgery, but no significant change was observed between three and six months after surgery. There were no cases in which the MTA was clearly confirmed before surgery in the TOF reconstructed images, but the MTA was clearly confirmed in 55% (11/20 cases) of hemispheres three months after surgery and in 85% (17/20 cases) of hemispheres six months after surgery. The crosssectional area of the STA parietal branch, which was the donor for direct revascularization, had increased by more than 150% compared to before surgery in 55% (11/20 cases) of hemispheres three months after surgery. CONCLUSIONS: Indirect revascularization can be expected three months after combined revascularization surgery for moyamoya disease. The MTA, which has not received much attention in terms of indirect revascularization for moyamoya disease patients thus far, was found to be a useful blood flow source for indirect revascularization in combined revascularization surgery for patients with moyamoya disease. Whether or not the cross-sectional area of the superficial temporal artery used as a donor for direct revascularization increased in the medium to long term varied on a case-by-case basis.

Surgical repair of torn base of ruptured middle cerebral artery trifurcation aneurysm.

BACKGROUND: Treating complex middle cerebral artery (MCA) trifurcation aneurysms requires a delicate balance between achieving aneurysm obliteration and preserving vascular integrity. Various cerebral revascularization techniques, including bypass, and clip reconstruction are considered individually or in combination. METHODS: This case report outlines a successful repair of a ruptured neck and base of MCA trifurcation aneurysm using a suturing-clip reconstruction technique. Temporary aneurysm trapping was implemented, with maintained elevated blood pressure to ensure collateral perfusion during repair of ruptured base and neck of MCA aneurysm. CONCLUSION: The suturing-clip reconstruction exhibited long-term radiological stability, emerging as a valuable alternative for managing challenging MCA trifurcation aneurysms.

[Various Bypass Surgery:Preoperative Simulation for STA-MCA Bypass].

In STA-MCA bypass surgery, it is important to select the optimal recipient using preoperative simulation to avoid complications. We report a preoperative simulation for STA-MCA bypass using the Brain LAB iPLAN platform®BRAIN LAB)and the 3DCG simulation software GRID®Kompath). Here, we introduce the basics and applications of preoperative simulation for occlusive atherosclerotic lesions and present a target bypass for periventricular anastomosis and peripheral vessels of aneurysms in Moyamoya disease. By creating and visualizing 3D fusion images, the optimal donor and recipient can be selected. Determining the skin incision and extent of craniotomy according to the case is also applicable to the minimally invasive STA-MCA bypass. Preoperative simulations enable accurate pinpoint bypass surgery and prevent complications.

[Basic and Advanced Techniques of Anastomosis in Deep Surgical Fields:STA-SCA Anastomosis].

This article detailly describes the subtemporal-transtentorial STA-SCA bypass technique. Through temporal base drilling, copious cerebrospinal fluid evacuation before retraction, and sufficient retraction of the temporal lobe preserving the veins of the temporal base would be primodial to obtain an appropriate surgical field. Refrection of the tentrial free edge and identification of recipient SCA posterior to the entry point of the trochlear nerve into the cavernous sinus is a micro-anatomical key. Bilateral bayonet-type needle holders and forceps should be used not to shadow the surgical corridor with one's hands.

Angiographic measurement of the superficial temporal artery for potential use in cerebral bypass surgery: a combined radiological and cadaveric study.

PURPOSE: This study aims to investigate the microsurgical anatomy of the superficial temporal artery (STA), explore the relationship between STA length and lumen diameter, and develop a reliable radiologic method for selecting STA segments for bypass surgery. METHODS: This study used 10 cadaveric dissections (20 STAs, both sides) and 20 retrospective radiological examinations (40 STAs, both sides), employing curved multiplanar reformation and flow color lookup table (CLUT) DICOM processing. Measurements included vessel lumen diameters and luminal cross-sectional thicknesses 3 mm proximal to the STA bifurcation, 3 mm distal to the frontal branch, 5 cm distal to the frontal branch, 3 mm distal to the parietal branch, and 5 cm distal to the parietal branch. The distance between the STA bifurcation and the superior zygomatic border (SZB) was also measured. In our analysis, descriptive statistics encompassed mean, standard deviation (SD), standard error, minimum and maximum values, and distributions. Comparative statistics were performed using Student's t-test, with statistical significance set at p < 0.05. RESULTS: There were no statistically significant differences between STA measurements of bifurcation distances (p = 0.88) and lumen diameters (p = 0.46) between cadavers and radiological measures. However, lumen thicknesses were larger in frontal branches than parietal branches at the seventh and eighth centimeter (p = 0.012, p = 0.039). Branches became thinner distally from the zygoma in both cadavers and radiological image measurements. CONCLUSION: The CLUT DICOM processing radiological measures provided the high-precision required to enable pre-surgical vessel selection for extracranial-intracranial bypass. The results show that STA vessel luminal diameters are sufficient (> 1 mm) for bypass surgery in the first 9 cm but gradually decrease after that. Also shown is that the choice of frontal versus parietal branches depends on individual anatomical features; therefore, careful preoperative radiological examination is critical.

Posterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Bypass versus Occipital Artery-Posterior Inferior Cerebellar Artery Bypass for Treating Posterior Circulation Aneurysms: A Systematic Review and Comparative Meta-Analysis.

BACKGROUND: When traditional therapies are unsuitable, revascularization becomes essential for managing posterior inferior cerebellar artery (PICA) or vertebral artery aneurysms. Notably, the PICA-PICA bypass has emerged as a promising option, overshadowing the occipital artery-PICA (OA-PICA) bypass. The objective was to compare the safety and efficacy of OA-PICA and PICA-PICA bypasses. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we conducted a systematic review and meta-analysis to evaluate the safety and efficacy of OA-PICA and PICA-PICA bypasses for treating posterior circulation aneurysms. RESULTS: We analyzed 13 studies for the PICA-PICA bypass and 16 studies on the OA-PICA bypass, involving 84 and 110 patients, respectively. The median average follow-up for PICA-PICA bypass was 8 months (2-50.3 months), while for OA-PICA, it was 27.8 months (6-84 months). The patency rate for OA-PICA was 97% (95% confidence interval [CI]: 92%-100%) and 100% (95% CI: 95%-100%) for PICA-PICA. Complication rates were 29% (95% CI: 10%-47%) for OA-PICA and 12% (95% CI: 3%-21%) for PICA-PICA. Good clinical outcomes were observed in 71% (95% CI: 52%-90%) of OA-PICA patients and 87% (95% CI: 75%-100%) of PICA-PICA patients. Procedure-related mortality was 1% (95% CI: 0%-6%) for OA-PICA and 1% (95% CI: 0%-10%) for PICA-PICA. CONCLUSIONS: Both procedures have demonstrated promising results in efficacy and safety. PICA-PICA exhibits slightly better patency rates, better clinical outcomes, and fewer complications, but with a lack of substantial follow-up and a smaller sample size. The choice between these procedures should be based on the surgeon's expertise and the patient's anatomy.

Localization of Maxillary Artery for Cerebral Revascularization: L-Shaped Perpendicular Two-Step Drilling Technique Stretching from the Foramen Ovale to Rotundum.

BACKGROUND: The use of the maxillary artery (MA) as a donor has increasingly become an alternative method for cerebral revascularization. Localization difficulties emerge due to rich infratemporal anatomical variations and the complicated relationships of the MA with neuromuscular structures. We propose an alternative localization method via the interforaminal route along the middle fossa floor. METHODS: Five silicone-injected adult cadaver heads (10 sides) were dissected. Safe and effective localization of the MA was evaluated. RESULTS: The MA displayed anatomical variations in relation to the lateral pterygoid muscle (LPM) and the mandibular nerve branches. The proposed L-shaped perpendicular 2-step drilling technique revealed a long MA segment that allowed generous rotation to the intracranial area for an end-to-end anastomosis. The first step of drilling involved medial-to-lateral expansion of foramen ovale up to the lateral border of the superior head of the LPM. The second step of drilling extended at an angle approximately 90° to the initial path and reached anteriorly to the foramen rotundum. The MA was localized by gently retracting the upper head of the LPM medially in a posterior-to-anterior direction. CONCLUSIONS: Considering all anatomical variations, the L-shaped perpendicular 2-step drilling technique through the interforaminal space is an attainable method to release an adequate length of MA. The advantages of this technique include the early identification of precise landmarks for the areas to be drilled, preserving all mandibular nerve branches, the deep temporal arteries, and maintaining the continuity of the LPM.

Cortical Spreading Depolarization in Moyamoya Vasculopathy: A Case Series.

BACKGROUND: Spreading depolarization describes a near-complete electrical discharge with altered local cerebral blood flow. It is described in association with acute and chronic diseases like hemorrhagic stroke or migraine. Moyamoya vasculopathy is a chronic, progressive cerebrovascular disorder leading to cerebral hypoperfusion, hemodynamically insufficient basal collateralization, and increased cortical microvascularization. METHODS: In a prospective case series, we monitored for spontaneous spreading depolarization activity by using intraoperative laser speckle imaging for real-time visualization and measurement of cortical perfusion and cerebrovascular reserve capacity during cerebral revascularization in 4 consecutive patients with moyamoya. RESULTS: Spontaneous spreading depolarization occurrence was documented in a patient with moyamoya before bypass grafting. Interestingly, this patient also exhibited a marked preoperative increase in angiographic collateral vessel formation. CONCLUSIONS: The spontaneous occurrence of SDs in moyamoya vasculopathy could potentially provide an explanation for localized cortical infarction and increased cortical microvascular density in these patients.

Functional and Neuropsychological Outcome After Surgical Treatment of Moyamoya Disease.

BACKGROUND: Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by progressive stenosis of the supraclinoid internal carotid artery. As a result of chronically decreased brain perfusion, eloquent areas of the brain become hypoperfused, leading to cognitive changes in patients. Repeated infarcts and bleeds produce clinically apparent neurologic deficits. OBJECTIVES: 1) To study the functional and neuropsychological outcome in MMD after revascularization surgery. 2) To find postrevascularization correlation between functional and neuropsychological improvement and radiologic improvement. METHODS: A single-center prospective and analytic study was carried out including 21 patients with MMD during the study period from March 2021 to December 2022. Patients were evaluated and compared before and after revascularization for functional, neuropsychological, and radiologic status. RESULTS: Postoperative functional outcome in terms of modified Rankin Scale score showed improvement in 33.33% of cases (P = 0.0769). An overall improving trend was observed in different neuropsychological domains in both adult and pediatric age groups. However, the trend of neuropsychological improvement was better in adults compared with pediatric patients. Radiologic outcome in the form of the Angiographic Outcome Score (AOS) significantly improved after revascularization (P = 0.0001). There was a trend toward improvement in magnetic resonance imaging (MRI) perfusion in the middle cerebral artery and anterior cerebral artery territories, 4.7% (P = 0.075) and 9.33% (P = 0.058) respectively, compared with preoperative MRI perfusion. CONCLUSIONS: After revascularization, significant improvement occurred in functional and neuropsychological status. This result was also shown radiologically as evidenced by improvement in MRI perfusion and cerebral angiography.

Surgical revascularization as a procedure to prevent neurological complications in children with moyamoya syndrome associated with neurofibromatosis I: a single institution case series.

BACKGROUND: The optimal timing and surgical approach for surgical revascularization in patients with moyamoya syndrome (MMS) associated with neurofibromatosis type I (NF1) remain so far elusive. We aimed to compare the long-term clinical, radiological, and cognitive effects of different revascularization procedures in a pediatric cohort of NF1-associated MMS. METHODS: We reviewed the clinical, radiological, and surgical data of 26 patients with NF1-associated MMS diagnosed at our institution between 2012 and 2022, at the clinical onset and last follow-up. RESULTS: Indirect bypasses were performed in 12/26 patients (57.1%), while combined direct and indirect procedures in 9/26 subjects (42.9%); 5 patients did not undergo surgery. Through logistic regression analysis, pathological Wechsler Intelligence Scale for Children (WISC) at onset was found to be associated with symptom improvement at 1-year follow up (p = 0.006). No significant differences were found in long-term neurocognitive outcome and stroke rate in patients receiving combined or indirect bypass (p > 0.05). CONCLUSIONS: Currently, whether combined or indirect bypass should be considered the treatment of choice in pediatric patients with NF1-associated MMS remains unclear, as well as the optimal time approach. In our series, no significant differences were found in long-term neurocognitive outcome and stroke rate between patients treated with either of these two approaches. Clinical evidence supports the crucial role of early diagnosis and surgical revascularization in subjects with MMS-associated NF1, even in case of mildly symptomatic vasculopathy. This allows to achieve a good long-term outcome with improved intellectual function and prevention of stroke and seizure in these patients.

Intracranial-intracranial bypass strategies for the treatment of complex intracranial aneurysms: anatomical characteristics and surgical intervention.

OBJECTIVE: The effectiveness of revascularization for complex aneurysms is well-established. This study aimed to describe the technical characteristics and clinical efficacy of intracranial-to-intracranial (IC-IC) bypass for the treatment of complex intracranial aneurysms. METHODS: We retrospectively reviewed all patients with aneurysms who underwent a preplanned combination of surgical or endovascular treatment and IC-IC bypass at our institution between January 2006 and September 2023. IC-IC bypass techniques included four strategies: type A (end-to-end reanastomosis), type B (end-to-side reimplantation), type C (in situ side-to-side anastomosis), and type D (IC-IC bypass with a graft vessel). RESULTS: During the study period, ten patients with aneurysms each underwent IC-IC bypass surgery. Aneurysms were located in the middle cerebral artery (60.0%), anterior temporal artery (10.0%), anterior cerebral artery (20.0%), and vertebral artery (10.0%). There were three saccular aneurysms (30.0%), two fusiform aneurysms (20.0%), one dissecting aneurysm (10.0%), and four pseudoaneurysms (40.0%). We performed the type A strategy on five patients (50.0%), type B on one (10.0%), type C on one (10.0%), and type D on three (30.0%). During a mean period of 68.3 months, good clinical outcomes (modified Rankin Scale score, 0-2) were observed in all patients. Follow-up angiography demonstrated complete aneurysmal obliteration in all patients and good bypass patency in nine of ten patients (90.0%). CONCLUSION: The treatment of complex aneurysms remains a challenge with conventional surgical or endovascular treatments. IC-IC bypass surgery is a useful technique, associated with favorable clinical outcomes, for treating complex aneurysms.

Complications associated with combined direct and indirect bypass in Moyamoya Disease: A meta-analysis.

Bypass revascularization helps prevent complications in Moyamoya Disease (MMD). To systematically review complications associated with combined direct and indirect (CB) bypass in MMD and analyze differences between the adult and pediatric populations. A systematic literature review was conducted per PRISMA guidelines. PUBMED, Cochrane Library, Web of Science, and CINAHL, were queried from January 1980 to March 2022. Complications were defined as any event in the immediate post-surgical period of a minimum 3 months follow-up. Exclusion criteria included lack of surgical complication reports, non-English articles, and CB unspecified or reported separately. 18 final studies were included of 1580 procured. 1151 patients (per study range = 10-150, mean = 63.9) were analyzed. 9 (50.0%) studies included pediatric patients. There were 32 total hemorrhagic, 74 total ischemic and 16 total seizure complications, resulting in a rate of 0.04 (95% CI 0.03, 0.06), 0.7 (95% CI 0.04, 0.10) and 0.03 (95% CI 0.02, 0.05), respectively. The rate of hemorrhagic complications in the pediatric showed no significant difference from the adult subgroup (0.03 (95% CI 0.01-0.08) vs. 0.06 (95% CI 0.04-0.10, p = 0.19), such as the rate of ischemic complications (0.12 (95% CI 0.07-0.23) vs. 0.09 (95% CI 0.05-0.14, p = 0.40). Ischemia is the most common complication in CB for MMD. Pediatric patients had similar hemorrhagic and ischemic complication rates compared to adults.

Evidence of pial synagiosis through ventriculoperitoneal shunt entry site in a patient who manifested Moyamoya syndrome later in childhood: A case report and historical perspective.

The term Moyamoya , or "puff of smoke" in Japanese , was first used in 1969 by Suzuki and Takaku to describe the classical appearance of collateral blood vessels in response to progressive vascular stenosis of distal internal carotid artery (ICA). Such condition may result in various clinical presentations ranging from strokes to developmental delays. In order to cease the progression of such stenotic vasculopathy, several means of revascularization have been developed over the years. In this paper we present a case of a two-year-old girl with history of myelomeningocele repair and ventriculoperitoneal shunt insertion followed by manifestation of Moyamoya syndrome later in childhood as an evidence of revascularization through a burr hole. To our knowledge, this paper is the first of its kind to report such findings in one patient. Moreover, this paper provides a historical perspective on the development of different types of revascularization techniques.

Efficacy and Safety of Extracranial-Intracranial Bypass Surgery for Posterior Circulation Aneurysms: A Systematic Review and Single-Arm Meta-Analysis.

OBJECTIVE: Treating complex posterior circulation aneurysms poses challenges, and extracranial to intracranial (EC-IC) bypass techniques are potential therapeutic options. However, the safety and efficacy of this approach for posterior circulation aneurysms remain unclear. The study's objective was to assess the safety and efficacy of EC-IC bypass in these aneurysms. METHODS: Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we conducted a systematic review on EC-IC revascularization for posterior circulation aneurysms. Included studies had at least 4 patients and reported data on mortality, patency, complications, or clinical outcomes. Favorable clinical outcomes were defined as modified Rankin Scale below 3 or Glasgow Outcome Scale above 3, and complications were any issues related to the bypass procedure. RESULTS: From 3036 articles reviewed, 22 studies involving 196 patients who underwent 210 EC-IC bypass procedures for posterior circulation aneurysms were selected. The median follow-up period of 14 studies was 31.66 months (6-61 months). Final follow-up indicated a high bypass patency rate of 96% [95% confidence interval [CI]: 91%-100%; I2 = 12%], with a mortality rate of 5% [95% CI: 1%-9%; I2 = 0%]. Additionally, 83% [95% CI: 70%-96%; I2 = 77%] of patients showed good outcomes at the last follow-up. Complications were observed in 40% [95% CI: 26%-55%; I2 = 80%]. Heterogeneity was associated with specific studies. CONCLUSIONS: EC-IC bypass procedures are a viable treatment option for posterior circulation aneurysms, with high bypass patency rates and favorable clinical outcomes. However, complications, especially neurological deficits, exist. Open revascularization remains essential for neurovascular surgeons dealing with complex aneurysms.