The frequency of postoperative stroke in moyamoya disease following combined revascularization: a single-university series and systematic review

Adolescents with moyamoya disease: clinical features, surgical treatment and long-term outcomes

BACKGROUND

This study aimed to elucidate the clinical features, surgical treatment and long-term outcomes of adolescent patients with moyamoya disease.

METHODS

We reviewed consecutive patients with moyamoya vasculopathy who were admitted to our hospital from 2009 to 2015 to identify adolescent patients with moyamoya disease. Clinical features, surgical treatment and long-term outcomes were analyzed. Follow-up was performed by face-to-face or structured telephone interviews. Outcome measures were future stroke events. We performed univariate and multivariate time-to-event analyses to identify risk factors associated with future stroke events.

RESULTS

A total of 95 adolescent patients with moyamoya disease (age at onset, 13.1 ± 2.3 years) were included in this study. During follow-up, 12 patients (12.6%) had stroke events. We found that the patients who underwent direct/combined bypass had a significantly lower risk of future strokes [hazard ratio (HR), 0.16; 95% confidence interval (CI), 0.03-0.74; P = 0.019] compared to patients who underwent indirect bypass.

CONCLUSIONS

Our results demonstrate that direct/combined bypass can be more effective in preventing future strokes than indirect bypass in adolescent patients with moyamoya disease.

Incidence of Postoperative Hematomas Requiring Surgical Treatment in Neurosurgery: A Retrospective Observational Study

OBJECTIVE

We aimed to characterize the occurrence of postoperative hematoma (POH) after neurosurgery overall and according to procedure type and describe the prevalence of possible confounders.

METHODS

Patient data between 2010 and 2012 at the Department of Neurosurgery in Helsinki University Hospital were retrospectively analyzed. A data search was performed according to the type of surgery including craniotomies; shunt procedures, spine surgery, and spinal cord stimulator implantation. We analyzed basic preoperative characteristics, as well as data about the initial intervention, perioperative period, revision operation and neurologic recovery (after craniotomy only).

RESULTS

The overall incidence of POH requiring reoperation was 0.6% (n = 56/8783) to 0.6% (n = 26/4726) after craniotomy, 0% (n = 0/928) after shunting procedure, 1.1% (n = 30/2870) after spine surgery, and 0% (n = 0/259) after implantation of a spinal cord stimulator. Craniotomy types with higher POH incidence were decompressive craniectomy (7.9%, n = 7/89), cranioplasty (3.6%, n = 4/112), bypass surgery (1.7%, n = 1/60), and epidural hematoma evacuation (1.6%, n = 1/64). After spinal surgery, POH was observed in 1.1% of cervical and 2.1% of thoracolumbar operations, whereas 46.7% were multilevel procedures. 64.3% of patients with POH and 84.6% of patients undergoing craniotomy had postoperative hypertension (systolic blood pressure >160 mm Hg or lower if indicated). Poor outcome (Glasgow Outcome Scale score 1-3), whereas death at 6 months after craniotomy was detected in 40.9% and 21.7%. respectively, of patients with POH who underwent craniotomy.

CONCLUSIONS

POH after neurosurgery was rare in this series but was associated with poor outcome. Identification of risk factors of bleeding, and avoiding them, if possible, might decrease the incidence of POH.

Bypass surgery versus medical treatment for symptomatic moyamoya disease in adults

OBJECTIVE

In this study the authors evaluated whether extracranial-intracranial bypass surgery can prevent stroke occurrence and decrease mortality in adult patients with symptomatic moyamoya disease (MMD).

METHODS

The medical records of 249 consecutive adult patients with symptomatic MMD that was confirmed by digital subtraction angiography between 2002 and 2011 at 8 institutions were retrospectively reviewed. The study outcomes of stroke recurrence as a primary event and death during the 6-year follow-up and perioperative complications within 30 days as secondary events were compared between the bypass and medical treatment groups.

RESULTS

The bypass group comprised 158 (63.5%) patients, and the medical treatment group comprised 91 (36.5%) patients. For 249 adult patients with MMD, bypass surgery showed an HR of 0.48 (95% CI 0.27–0.86, p = 0.014) for stroke recurrence calculated by Cox regression analysis. However, for the 153 patients with ischemic MMD, the HR of bypass surgery for stroke recurrence was 1.07 (95% CI 0.43–2.66, p = 0.887). For the 96 patients with hemorrhagic MMD, the multivariable adjusted HR of bypass surgery for stroke recurrence was 0.18 (95% CI 0.06–0.49, p = 0.001). For the treatment modality, indirect bypass and direct bypass (or combined bypass) did not show any significant difference for stroke recurrence, perioperative stroke, or mortality (log rank; p = 0.524, p = 0.828, and p = 0.616, respectively).

CONCLUSIONS

During the treatment of symptomatic MMD in adults, bypass surgery reduces stroke recurrence for the hemorrhagic type, but it does not do so for the ischemic type. The best choice of bypass methods in adult patients with MMD is uncertain. In adult ischemic MMD, a prospective randomized study to evaluate the effectiveness and safety of bypass surgery to prevent recurrent stroke is necessary.

Neurocognitive Performance After Cerebral Revascularization in Adult Moyamoya Disease

BACKGROUND AND PURPOSE

Cerebral revascularization using EC-IC bypass is widely used to treat moyamoya disease, but the effects of surgery on cognition are unknown. We compared performance on formal neurocognitive testing in adults with moyamoya disease before and after undergoing direct EC-IC bypass.

METHODS

We performed a structured battery of 13 neurocognitive tests on 84 adults with moyamoya disease before and 6 months after EC-IC bypass. The results were analyzed using reliable change indices for each test, to minimize test-retest variability and practice effects.

RESULTS

Twelve patients (14%) showed significant decline postoperatively, 9 patients (11%) improved, and 63 patients (75%) were unchanged. Similar results were obtained when the analysis was confined to those who underwent unilateral (33) or bilateral (51) revascularization.

CONCLUSIONS

The majority of patients showed neither significant decline nor improvement in neurocognitive performance after EC-IC bypass surgery. Uncomplicated EC-IC bypass seems not to be a risk factor for cognitive decline in this patient population.

Radial Artery Fascial Flow-Through Free Flap for Combined Revascularization in Moyamoya Disease

BACKGROUND

Free flaps are commonly used by other surgical subspecialties for soft tissue reconstruction and revascularization. Cranial applications of these flaps have been limited to only a single case report.

OBJECTIVE

To present a new technique for combined revascularization in moyamoya disease using a flow-through free flap.

METHODS

Data were obtained from an Institutional Review Board-approved, prospectively maintained database with informed consent from the patient.

RESULTS

A 28-yr-old patient presented with progressive stenosis of the proximal anterior cerebral artery resulting in ischemic infarcts. Direct revascularization of the anterior cerebral artery territory and indirect revascularization of the middle cerebral artery with a large vascularized fascial pedicle was performed.

CONCLUSION

Flow-through free flaps offer a unique combination of revascularization and a large vascularized pedicle. This technique highlights the application of these flaps for revascularization in moyamoya disease and the value of multidisciplinary collaboration. Revascularization will likely play an increasing role in the open surgical treatment of cerebrovascular disease. We believe that flow-through free flaps will be a contribution to the future of revascularization in neurosurgery.

Meta-analysis of the surgical outcomes of symptomatic moyamoya disease in adults

OBJECTIVE The purpose of this study was to evaluate treatment outcomes of future stroke prevention, perioperative complications, and angiographic revascularization in adults with symptomatic moyamoya disease (MMD) according to treatment modalities and surgical techniques. METHODS A systemic literature review was performed based on searches of the PubMed, Embase, and Cochrane Central databases. A fixed-effects model was used in cases of heterogeneity less than 50%. Publication bias was determined by Begg's funnel plot, Egger's test of the intercept, and the Begg and Mazumdar rank correlation test. RESULTS Eleven articles were included in the meta-analysis. Bypass surgery significantly decreased the future stroke events compared with conservative treatments in adult MMD (odds ratio [OR] 0.301, p < 0.001). Direct bypass showed better future stroke prevention than indirect bypass (OR 0.494, p = 0.028). There was no meaningful difference in perioperative complications between direct and indirect bypass (OR 0.665, p = 0.176). Direct bypass was associated with better angiographic outcomes than indirect bypass (OR 6.832, p < 0.001). CONCLUSIONS Bypass surgery can be effective in preventing future stoke events in adults with MMD. Direct bypass seems to provide better risk reduction with respect to stroke than indirect bypass in these patients.

Synergistic Interactions Between Direct and Indirect Bypasses in Combined Procedures: The Significance of Indirect Bypasses in Moyamoya Disease

BACKGROUND: Whether additional indirect bypasses effectively contribute to revascularization in combined procedures remains unclear in patients with moyamoya disease.

OBJECTIVE: To evaluate the longitudinal changes associated with combined procedures while following up pediatric and adult patients long term and to assess whether any other clinical factors or hemodynamic parameters affected these changes to determine an optimal surgical strategy.

METHODS: We studied 58 hemispheres in 43 adults and 39 hemispheres in 26 children who underwent combined revascularization for moyamoya disease. To evaluate bypass development, we assessed the sizes of the superficial temporal artery and middle meningeal artery using magnetic resonance angiography. Multivariate analysis determined the effects of multiple variables on bypass development.

RESULTS: Indirect bypass (middle meningeal artery) development occurred in 95% and 78% of the pediatric and adult hemispheres, respectively. Of these, dual development of direct and indirect bypasses occurred in 54% of the pediatric hemispheres and in 47% of the adult hemispheres. Reciprocal superficial temporal artery regression occurred in 28% of the hemispheres during the transition from the postoperative acute phase to the chronic phase during indirect bypass development. Good indirect bypass development was associated with adult hemispheres at Suzuki stage 4 or greater (odds ratio, 7.4; 95% confidence interval, 1.4-39.4; P = .02). Disease onset type and preoperative hemodynamic parameters were not considered predictors for the development of surgical revascularization.

CONCLUSION: Simultaneous direct and indirect bypass development was most frequently observed, regardless of patient age and hemodynamic status. Applying indirect bypass as an adjunct to direct bypass could maximize revascularization in adults and children.

Characteristics of infarction after encephaloduroarteriosynangiosis in young patients with moyamoya disease

OBJECTIVE Young patients with moyamoya disease can exhibit infarction after revascularization surgery. This analysis of the characteristics of infarction after encephaloduroarteriosynangiosis (EDAS) in young patients with moyamoya disease was undertaken in an effort to elucidate the infarction mechanism. METHODS The authors retrospectively collected clinical information and reviewed pre- and postoperative MRI studies from cases involving patients younger than 18 years who underwent EDAS for the treatment of moyamoya disease between January 2012 and February 2015. Infarction patterns were categorized into watershed, territorial, or mixed pattern. The Wilcoxon rank sum test, chi-square test, and Fisher exact test were used to compare the clinical and imaging variables between patient groups. The characteristics of patients with and without postoperative infarction were compared using univariate and multivariate analysis. The cumulative proportion of patients without postoperative infarction according to operation stage was calculated using the Kaplan-Meier method and the resulting curves were compared using the log-rank test. RESULTS In 100 patients, 171 EDAS procedures had been performed. There were 38 cases of preoperative infarction in 35 patients and 20 cases of postoperative infarction in 13 patients. Territorial infarction was more frequent in the postoperative infarction group than in the preoperative infarction group (55.0% vs 37.8%, p = 0.037). Infarction was more common on the bilateral or contralateral side of the operation after first-stage EDAS (9 [75.0%] of 12 infarctions) than in the second-stage operation (2 [25.0%] of 8 infarctions), but the difference was not statistically significant (p = 0.068). The frequency of postoperative infarction was not significantly different depending on the stage of the operation (p = 0.694). CONCLUSIONS An acute infarction pattern after EDAS was more frequently territorial, suggesting an underlying occlusive mechanism. Operation stage did not affect the rate of postoperative infarction occurrence.

Subcortical Low-Intensity Lesions on Fluid-Attenuated Inversion Recovery Images After Revascularization Surgery for Moyamoya Disease

OBJECTIVE

Although uncommon, subcortical low-intensity (SCLI) changes on fluid-attenuated inversion recovery images are observed in various diseases, including cerebral ischemia. Here, we aimed to clarify the incidence and clinical implications of SCLI changes after revascularization surgery for moyamoya disease, focusing on the correlation with postoperative transient neurologic events (TNEs).

METHODS

In this retrospective case series analysis, we included 10 hemispheres from 9 adults with moyamoya disease who underwent revascularization surgery. Subcortical signal intensity at the 5 gyri around the anastomosis point was quantitatively measured at 1 week and 3 months postoperatively. Changes in cerebral blood flow (CBF) were assessed using single-photon emission computed tomography.

RESULTS

Images taken 1 week after surgery showed widespread SCLI changes below the operative fields in all 10 cases, but these changes normalized by 3 months. In addition, the changes in signal intensity at anastomoses negatively correlated with the changes in CBF (R² = 0.36; P = 0.039). Postoperative TNEs occurred in 6 cases (60%) but were resolved within 17 days after surgery. Postoperative CBF increased in 9 of the 10 cases, with a median of 23%; however, these increases were not associated with the development of TNEs. The SCLI changes at the anastomosis points did not differ by the experience of TNEs.

CONCLUSIONS

Early after surgery, SCLI changes are common findings below the operative fields but negatively correlate with increases in CBF. Although no significant association was found between TNEs and the SCLI changes, the synchronized development of these phenomena may suggest a common underlying pathogenesis.

Grading of moyamoya disease allows stratification for postoperative ischemia in bilateral revascularization surgery

BACKGROUND

Moyamoya disease (MMD) may be graded based on DSA, the presence of ischemia in MRI and cerebrovascular reserve capacity allowing the prediction of ischemic symptoms in patients. Cerebral ischemia represents a severe complication in revascularization surgery. Focusing on different clinical features of hemodynamic impairment, MMD grading may allow prediction of ischemic complications. It was the aim to analyze whether MMD grading stratifies for ischemic complications in revascularization surgery for MMD.

METHOD

In 37 MMD patients a bilateral, standardized, one-staged revascularization approach consisting of STA-MCA bypass/encephalomyosynangiosis (EMS) and single EMS on the contralateral hemisphere was performed. Clinical data including DSA, MRI and rCBF (Xenon-CT) studies were assessed and used for grading MMD. All patients were observed on the ICU for at least 24 h and received CT imaging on the first postoperative day and in case of neurological deterioration. Ischemic complications were analyzed until the day of discharge and at 6-month follow-up.

RESULTS

Grading of MMD revealed 11 hemispheres (15 %) as grade I, 33 hemispheres (44 %) as grade II and 30 hemispheres (41 %) as grade III. Eight ischemic complications were observed (11 %). MMD grading demonstrated a significant correlation with ischemic complications: 0 complications in grade I, 3 in grade II (9 %) and 5 in grade III hemispheres (16 %; p < 0.05, Fisher's exact test).

CONCLUSIONS

The proposed grading system allows to stratify for ischemic complications in MMD patients that receive bilateral, one-staged revascularization surgery. Future studies will have to investigate its use for predicting ischemic complications in other revascularization strategies for MMD.

The Efficacy of Single Barrel Superficial Temporal Artery-middle Cerebral Artery Bypass in Treatment of Adult Patients with Ischemic-type Moyamoya Disease

OBJECTIVE

So far, there is no study answering the question of which type of surgical technique is practically the most useful in the treatment of adult patients with ischemic type moyamoya disease (MMD). We evaluated the efficacy of single barrel superficial temporal artery (STA)-middle cerebral artery (MCA) bypass in the treatment of adult patients with ischemic type MMD by retrospectively collecting clinical and radiological data.

MATERIALS AND METHODS

A retrospective review identified 31 adult patients who underwent 43 single barrel STA-MCA bypass procedures performed for treatment of ischemic-type MMD between 2006 and 2014. The male to female ratio was 17:14 and the mean age was 41 years (range, 21-65 years). Peri-operative complications, angiographic and clinical outcomes were analyzed retrospectively.

RESULTS

The permanent neurological morbidity and mortality rates were 2.3% and 0%, respectively. During the observation period of a mean of 35 months (range, 12-73 months), 29 patients (93.5%) had no further cerebrovascular events and transient ischemic attack occurred in two patients (6.5%), resulting in an annual stroke risk of 2.2%. Follow-up computed tomography perfusion (CTP) (mean, 18.4 months after surgery) documented improved cerebral hemodynamics in the revascularized hemispheres (p < 0.001). Post-operative patency was clearly verified in 38 bypasses (88.4%) of 43 bypasses on follow-up imaging (mean, 16.5 months).

CONCLUSION

Our results suggest that single barrel STA-MCA bypass with wide dural opening is safe and durable method of cerebral revascularization in adult patients with ischemic type MMD and can be considered as a potential treatment option for adult patients with ischemic type MMD.

Topographic changes in cerebral blood flow and reduced white matter integrity in the first 2 weeks following revascularization surgery in adult moyamoya disease

OBJECTIVE After revascularization surgery, hyperperfusion and ischemia are associated with morbidity and mortality in adult moyamoya disease (MMD). However, structural changes within the brain following revascularization surgery, especially in the early postsurgical period, have not been thoroughly studied. Such knowledge may enable improved monitoring and clinical management of hyperperfusion and ischemia in MMD. Thus, the objective of this study was to investigate the topographic and temporal profiles of cerebral perfusion and related white matter microstructural changes following revascularization surgery in adult MMD. METHODS The authors analyzed 20 consecutive surgeries performed in 17 adults. Diffusion imaging in parallel with serial measurements of regional cerebral blood flow (rCBF) using SPECT was performed. Both voxel-based and region-of-interest analyses were performed, comparing neuroimaging parameters of postoperative hemispheres with those of preoperative hemispheres at 4 different time points within 2 weeks after surgery. RESULTS Voxel-based analysis showed a distinct topographic pattern of cerebral perfusion, characterized by increased rCBF in the basal ganglia for the first several days and gradually increased rCBF in the lateral prefrontal cortex over 1 week (p < 0.001). Decreased rCBF was also observed in the lateral prefrontal cortex, occipital lobe, and cerebellum contralateral to the surgical hemisphere (p < 0.001). Reduced fractional anisotropy (FA) and axial diffusivity (AD), as well as increased radial diffusivity (RD), were demonstrated in both the anterior and posterior limbs of the internal capsule (p < 0.001). Diffusion parameters demonstrated the greatest changes in both FA and RD on Days 1-2 and in AD on Days 3-6; FA, RD, and AD recovered to preoperative levels on Day 14. Patients with transient neurological deteriorations (TNDs), as compared with those without, demonstrated greater increases in rCBF in both the lateral prefrontal cortex and striatum as well as smaller FAs in the posterior limb of the internal capsule (p < 0.05). CONCLUSIONS The excessively increased rCBF and the recovery process were heterogeneous across brain regions, demonstrating a distinct topographic pattern during the initial 2 weeks following revascularization surgery in MMD. Temporary impairments in the deep white matter tract and immediate postoperative ischemia were also identified. The study results characterized postoperative brain perfusion as well as the impact of revascularization surgery on the brain microstructure. Notably, rCBF and white matter changes correlated to TNDs, suggesting that these changes represent potential neuroimaging markers for tracking tissue structural changes associated with hyperperfusion during the acute postoperative period following revascularization surgery for MMD.

Direct Anastomosis Using Occipital Artery for Additional Revascularization in Moyamoya Disease After Combined Superficial Temporal Artery–Middle Cerebral Artery and Indirect Bypass

BACKGROUND: The posterior cerebral artery (PCA) is involved in approximately 30% of moyamoya disease (MMD) cases. However, there have been insufficient reports describing revascularization techniques in the posterior portion of the brain, particularly of direct anastomosis.

OBJECTIVE: To perform a technical assessment in patients with MMD who underwent either occipital artery (OA)–PCA bypass or OA–middle cerebral artery (MCA) bypass.

METHODS: A total of 428 revascularization procedures in 368 patients were retrospectively assessed by reviewing clinical charts and radiological data.

RESULTS: Ten patients (3.5%) were treated with direct bypass after the anterior revascularization with a median interval of 30 months (range, 5 months-16 years). Seven patients were &lt; 18 years of age (average age, 17.5 ± 15.6 years). Preoperative symptoms included transient motor deficits involving the lower extremities (n = 5), visual disturbances (n = 6), and cerebral infarctions (n = 6). A favorable outcome (modified Rankin Scale score &lt; 3) was achieved in 9 of these 10 patients. Direct anastomosis was performed in 3 hemispheres with an OA-MCA bypass and in 8 hemispheres with an OA-PCA bypass. Patency of the direct bypass was confirmed on angiogram in 7 of 7 patients who underwent conventional angiogram performed within 1 year after the surgery. None of the 10 patients demonstrated cerebral infarctions after the posterior revascularization.

CONCLUSION: In MMD, symptomatic PCA regression after anterior revascularization was found predominantly in children and young adults. Direct anastomosis in the posterior portion of the brain can be successfully achieved and is effective in preventing ischemic events.

Low flow velocity in the middle cerebral artery predicting infarction after bypass surgery in adult moyamoya disease

OBJECTIVE Direct and indirect bypass surgeries are recognized as the most effective treatments for preventing further stroke in adults with moyamoya disease (MMD). However, the risk factors for postoperative infarction after bypass surgery for MMD are not well established. Therefore, the objective of this study was to investigate the risk factors for postoperative infarction. In particular, the authors sought to determine whether transcranial Doppler (TCD) ultrasonography measurements of mean flow velocity (MFV) in the middle cerebral artery (MCA) could predict postrevascularization infarction. METHODS The medical records of patients with MMD who underwent direct bypass surgery at the authors' institution between July 2012 and April 2015 were reviewed. The MFV in the MCA was measured with TCD ultrasonography and categorized as high (> 80 cm/sec), medium (40-80 cm/sec), and low (< 40 cm/sec). Postoperative MRI, including diffusion-weighted imaging, was performed for all patients within a week of their surgery. Angiographic findings were classified according to the Suzuki scale. Postrevascularization infarction was defined as any diffusion restriction on postoperative MRI scans. Postoperative neurological status was assessed through a clinical chart review, and the modified Rankin Scale was used to evaluate clinical outcomes. RESULTS Of 43 hemispheres in which bypass surgery for MMD was performed, 11 showed postrevascularization infarction. Ten of these hemispheres had low MFV and 1 had medium MFV in the ipsilateral MCA. In both univariate and multivariate analyses, a low MFV was associated with postrevascularization infarction (adjusted OR 109.2, 95% CI 1.9-6245.3). A low MFV was also statistically significantly associated with more advanced MMD stage (p = 0.02). CONCLUSIONS A low MFV in the ipsilateral MCA may predict postrevascularization infarction. Bypass surgery for MMD appears to be safe in early-stage MMD. Results of TCD ultrasonography provide clinical data on the hemodynamics in MMD patients before and after revascularization.

Moyamoya Disease: Treatment and Outcomes

Although the pathogenesis of moyamoya disease (MMD) has not been fully elucidated, the effectiveness of surgical revascularization in preventing stroke has been addressed by many studies. The main mechanism of surgical revascularization is augmenting the intracranial blood flow using an external carotid system by either direct bypass or pial synangiosis. This can improve resting cerebral blood flow as well as vascular reserve capacity. For direct revascularization, the superficial temporal artery is used as the donor artery in most cases, although the occipital artery may be used in limited cases. Usually, the cortical branch of the middle cerebral artery is selected as the recipient of direct anastomosis. As for indirect revascularization, various techniques using different kinds of connective tissues have been introduced. In some cases, reinforcing the anterior cerebral artery and the posterior cerebral artery territories can be considered. The effectiveness of surgical revascularization for preventing ischemic stroke had been generally accepted by many studies. However, for preventing hemorrhagic stroke, new evidence has been added by a recent randomized controlled trial. The incidence of peri-operative complications such as stroke and hyperperfusion syndrome seems to be high due to the nature of the disease and technical demands for treatment. Preventing and adequately managing these complications are essential for ensuring the benefits of surgery.

Universal Bypass for Treatment of Symptomatic Moyamoya Disease or Moyamoya Syndrome. Analysis of a Personal Case Series on Behalf of the Italian Moyamoya Association

BACKGROUND

Moyamoya (MM) is a very rare cerebrovascular disease, particularly in Caucasians. We describe the results of an Italian case series where the mainstay of treatment was a bypass or a combined approach.

METHODS

An analysis of a prospectively collected database was carried out. The main objective was to investigate (1) the risk of perioperative stroke and surgical complications, (2) the risk of new ischemic events, and (3) the risk of new hemorrhages at follow-up (mean follow-up: 2.2 years).

RESULTS

Between January 2011 and January 2015 we carried out 34 bypasses in 23 patients with MM (15 MM disease, 5 unilateral MM, 3 MM syndrome); mean age was 34 (range:1-57). The mortality and definitive morbidity rates were 0 %. Two patients suffered from transient aphasia and one developed partial palsy of the facial nerve. Five of the 12 patients with preoperative fixed deficits improved. No patient with preoperative ischemia experienced new ischemic symptoms. Rebleeding occurred in 1 of the 11 patients with a hemorrhagic presentation (9 %).

CONCLUSIONS

The bypass/combined approach to MM appears to have a favorable risk profile and preventive effectiveness, particularly on TIAs and ischemic stroke.

Progress on Complications of Direct Bypass for Moyamoya Disease

Moyamoya disease (MMD) involves progressive occlusion of the intracranial internal carotid artery resulting in formation of moyamoya-like vessels at the base of the brain. It can be characterized by hemorrhage or ischemia. Direct vascular bypass is the main and most effective treatment of MMD. However, patients with MMD differ from those with normal cerebral vessels. MMD patients have unstable intracranial artery hemodynamics and a poor blood flow reserve; therefore, during the direct bypass of superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis, perioperative risk factors and anesthesia can affect the hemodynamics of these patients. When brain tissue cannot tolerate a high blood flow rate, it becomes prone to hyperperfusion syndrome, which leads to neurological function defects and can even cause intracranial hemorrhage in severe cases. The brain tissue is prone to infarction when hemodynamic equilibrium is affected. In addition, bypass vessels become susceptible to occlusion or atrophy when blood resistance increases. Even compression of the temporalis affects bypass vessels. Because the STA is used in MMD surgery, the scalp becomes ischemic and is likely to develop necrosis and infection. These complications of MMD surgery are difficult to manage and are not well understood. To date, no systematic studies of the complications that occur after direct bypass in MMD have been performed, and reported complications are hidden among various case studies; therefore, this paper presents a review and summary of the literature in PubMed on the complications of direct bypass in MMD.

Increased prevalence of autoimmune disease in patients with unilateral compared with bilateral moyamoya disease

OBJECT This study explored whether there were differences between the autoimmune disease prevalence rates in unilateral and bilateral moyamoya disease (MMD). METHODS The authors performed a retrospective review of data obtained from the medical records of their hospital, analyzing and comparing the clinical characteristics and prevalence rates of all autoimmune diseases that were associated with unilateral and bilateral MMD in their hospital from January 1995 to October 2014. RESULTS Three hundred sixteen patients with bilateral MMD and 68 with unilateral MMD were identified. The results indicated that patients with unilateral MMD were more likely to be female than were patients with bilateral MMD (67.6% vs 51.3%, p = 0.014, odds ratio [OR] 1.99). Overall, non-autoimmune comorbidities tended to be more prevalent in the unilateral MMD cases than in the bilateral MMD cases (17.6% vs 9.8%, p = 0.063, OR 1.97, chi-square test). Autoimmune thyroid disease and other autoimmune diseases also tended to be more prevalent in the unilateral MMD cases than in the bilateral MMD cases (19.1% vs 10.8%, p = 0.056, OR 1.96 and 8.8% vs 3.5%, p = 0.092, OR 2.77, respectively, chi-square test). The overall autoimmune disease prevalence in the unilateral MMD cases was significantly higher than in the bilateral MMD cases (26.5% vs 13.6%, p = 0.008, OR 2.29, 95% CI 1.22-4.28, chi-square test). Multiple logistic regression analysis showed that autoimmune disease was more likely to be associated with unilateral than with bilateral MMD (p = 0.039, OR 10.91, 95% CI 1.13-105.25). CONCLUSIONS This study indicated a higher overall autoimmune disease prevalence in unilateral than in bilateral MMD. Unilateral MMD may be more associated with autoimmune disease than bilateral MMD. Different pathogenetic mechanisms may underlie moyamoya vessel formation in unilateral and bilateral MMD.

Ischemic stroke in pediatric moyamoya disease associated with immune thrombocytopenia--a case report

CASE REPORT

A 10-year-old boy developed refractory bleeding and was diagnosed with immune thrombocytopenia (ITP). He was treated with steroids and intravenous immunoglobulin (IVIG). Five months later, however, he developed right homonymous hemianopsia, sensory aphasia, agraphia, and agnosia. MR imaging demonstrated multiple cerebral infarction in the bilateral cerebral hemispheres, and MR angiography revealed severe stenosis of the bilateral internal carotid arteries. He was diagnosed with moyamoya disease and successfully underwent surgical revascularization on both sides under IVIG therapy. However, multiple cerebral infarcts developed in the bilateral cerebral hemispheres 10 days after the second surgical revascularization when platelet counts were within normal limits. Furthermore, chronic subdural hematoma gradually increased in size after each surgery, which required burr hole surgery to resolve increased intracranial pressure, when platelet counts decreased to less than 10 × 10(9)/L.

CONCLUSION

This is the first report presenting a case with moyamoya disease coincident with ITP. Critical managements would be essential to reduce perioperative complications, because ITP is known to provoke both hemorrhagic and ischemic events through multiple mechanisms.

Long-Term Outcomes After Combined Revascularization Surgery in Adult Moyamoya Disease

Background and Purpose—

The surgical outcomes of adult moyamoya disease are rarely reported. We aimed to evaluate the long-term outcomes of combined revascularization surgery in patients with adult moyamoya disease.

Methods—

Combined revascularization surgery consisting of superficial temporal artery–middle cerebral artery anastomosis with encephalodurogaleosynangiosis was performed on 77 hemispheres in 60 patients. Clinical, angiographic, and hemodynamic states were evaluated retrospectively using quantitative methods preoperatively and postoperatively in the short-term (≈6 months) and long-term (≈5 years) periods. The mean clinical follow-up duration was 71.0±10.1 months (range, 60–104 months).

Results—

Clinical status improved until 6 months after surgery and remained stable thereafter, as assessed by the Karnofsky Performance Scale and modified Rankin Scale. The revascularization area relative to supratentorial area significantly increased in the long-term period compared with that in the short-term period (54.8% versus 44.2%; P <0.001). Cerebral blood flow in the territory of the middle cerebral artery improved in the short-term period compared with that in the preoperative period (68.7 versus 59.1; considering blood flow of the pons as 50; P <0.001) and thereafter became stable (65.5 in the long term; P =0.219). The annual risks of symptomatic hemorrhage and infarction were 0.4% and 0.2%, respectively, in the operated hemispheres.

Conclusions—

Combined revascularization surgery resulted in satisfactory long-term improvement in clinical, angiographic, and hemodynamic states and prevention of recurrent stroke.

Intraoperative assessment of cortical perfusion by indocyanine green videoangiography in surgical revascularization for moyamoya disease

BACKGROUND

Postoperative hyperperfusion is a potential complication of the direct bypass procedure for moyamoya disease (MMD). However, no reliable modality is available yet for the prediction of postoperative hyperperfusion during surgery for MMD. This study aimed to investigate whether semiquantitative analysis of indocyanine green (ICG) videoangiography could contribute to the prediction of postoperative hyperperfusion in MMD.

METHODS

This study included 12 hemispheres from 10 patients who underwent surgical revascularization for MMD. Intraoperative ICG videoangiography was performed before and after a direct bypass procedure. The ICG intensity-time curves were semiquantitatively analyzed to evaluate cortical perfusion by calculating the blood flow index (BFI). Using single-photon emission computed tomography (SPECT), postoperative cerebral blood flow measurements were performed thrice: immediately, and 2 and 7 days after surgery.

RESULTS

BFI significantly increased from 21.3 ± 10.5 to 38.4 ± 20.0 after bypass procedures in all the hemispheres (p < 0.01). The ratio of BFI before and after the bypass procedure was 2.4 ± 2.0, ranging from 0.5 to 8.0. Postoperative hyperperfusion was observed in nine of the 12 operated hemispheres within 7 days after surgery. Of these, three hemispheres developed hyperperfusion immediately after surgery. In the adult cases, the increase in the ratio of BFI after bypass was significantly greater in those who developed hyperperfusion immediately after surgery than in those who did not (6.5 ± 0.5 vs. 1.8 ± 2.1, p < 0.01). In contrast, no significant increase in BFI was observed in the pediatric MMD patients who experienced immediate hyperperfusion. No correlation between the changes in BFI and the occurrence of delayed hyperperfusion was observed.

CONCLUSIONS

Our results suggest that semiquantitative analysis of BFI by intraoperative ICG videoangiography is useful in evaluating changes in cortical perfusion after bypass procedures for MMD and can predict the occurrence of early-onset hyperperfusion in MMD patients after direct bypass.