Perioperative management protocols for children with moyamoya disease

Perioperative Management of Pediatric Patients with Moyamoya Arteriopathy

Pediatric patients with moyamoya arteriopathy are at high risk for developing new onset transient or permanent neurologic deficits secondary to cerebral hypoperfusion, particularly in the perioperative period. It is therefore essential to carefully manage these patients in a multidisciplinary, coordinated effort to reduce the risk of new permanent neurologic deficits. However, little has been published on perioperative management of pediatric patients with moyamoya, particularly in the early postoperative period during intensive care unit admission. Our pediatric neurocritical care team sought to create a multidisciplinary periprocedural evidence- and consensus-based care pathway for high-risk pediatric patients with moyamoya arteriopathy undergoing anesthesia for any reason to decrease the incidence of periprocedural stroke or transient ischemic attack (TIA). We reviewed the literature to identify risk factors associated with perioperative stroke or TIA among patients with moyamoya and to gather data supporting specific perioperative management strategies. A multidisciplinary team from pediatric anesthesia, neurocritical care, nursing, child life, neurosurgery, interventional neuroradiology, neurology, and hematology created a care pathway for children with moyamoya undergoing anesthesia, classifying them as either high or standard risk, and applying an individualized perioperative management plan to high-risk patients. The incidence of neurologic sequelae before and after pathway implementation will be compared in future studies.

Risk Factors and Imaging Biomarkers Associated With Perioperative Stroke in Pediatric Moyamoya Arteriopathy

Patients with moyamoya arteriopathy are at high risk for developing ischemic stroke in the perioperative period. We sought to evaluate whether preoperative clinical and neuroimaging biomarkers are associated with postoperative stroke and transient ischemic attack in children with moyamoya following revascularization surgery. We performed a retrospective chart review of pediatric patients who underwent revascularization surgery for moyamoya in the last 15 years. Fifty-three patients who underwent 69 surgeries met the inclusion criteria. We recorded clinical predictors of stroke or transient ischemic attack within 7 days following surgery. We used Suzuki stage and Composite Cerebrovascular Stenosis Score to analyze neuroimaging. Significant risk factors for developing postoperative stroke or transient ischemic attack were younger age at surgery (P = .004) and transient ischemic attack less than 1 month prior to surgery (P < .001). Children under 5 and those with recent preoperative ischemic events should be the focus of investigation to evaluate modifiable risk factors and targeted interventions.

Spinal Versus General Anesthesia for Cesarean Delivery in Pregnant Women With Moyamoya Disease: A Retrospective Observational Study

BACKGROUND

Moyamoya disease, a rare chronic cerebrovascular disease with a fragile vascular network at the base of the brain, can cause ischemic or hemorrhagic strokes or seizures. Precise blood pressure control and adequate analgesia are important for patients with moyamoya disease to prevent neurological events such as ischemia and hemorrhage. This study aimed to compare the intraoperative mean arterial pressure of pregnant women with moyamoya disease according to the mode of anesthesia (general anesthesia versus spinal anesthesia) used during cesarean delivery.

METHODS

We retrospectively reviewed the medical records of 87 cesarean deliveries in 74 patients who had been diagnosed with moyamoya disease before cesarean delivery. The primary outcome, intraoperative maximum mean arterial pressure during anesthesia, was compared according to the type of anesthesia administered (general versus spinal anesthesia). Other perioperative hemodynamic data (lowest mean arterial pressure, incidence of hypotension, vasopressor use, and antihypertensive agent use), maternal neurologic symptoms, neonatal outcomes (Apgar scores <7, ventilatory support, and intensive care unit admission), maternal and neonatal length of stay, postoperative pain scores, and rescue analgesic use were assessed as secondary outcomes.

RESULTS

While the lowest blood pressure during anesthesia and incidence of hypotension did not differ between the 2 groups, the maximum mean arterial pressure during anesthesia was lower in the spinal anesthesia group than that in the general anesthesia group (104.8 ± 2.5 vs 122.0 ± 4.6; P = .002). Study data did not support the claim that maternal neurologic symptoms differ according to the type of anesthesia used (5.6% vs 9.3%; P = .628); all patients recovered without any sequelae. The postoperative pain scores were lower, and fewer rescue analgesics were used in the spinal anesthesia group than in the general anesthesia group. Other maternal and neonatal outcomes were not different between the 2 groups.

CONCLUSIONS

Compared with general anesthesia, spinal anesthesia mitigated the maximum arterial blood pressure during cesarean delivery and improved postoperative pain in patients with moyamoya disease.

Current trends in pediatric moyamoya: a survey of international practitioners

OBJECTIVE

Moyamoya angiopathy (MM) is a chronic, progressive steno-occlusive arteriopathy of the distal internal carotid artery and its proximal branches. MM is recognized as a shared end-pathway common to a broad range of inciting pathologies, suggesting that tailored management is important. Pediatric MM differs from MM in adults. Currently, there are many uncertainties and controversies regarding the diagnosis and management of children with MM. Hence, we conducted an international survey to identify the contemporary management trends followed worldwide.

METHODS

A survey relating to lifestyle modifications, medical management, diagnosis, surgical management, and follow-up for pediatric MM was circulated across web-based platforms, through various international pediatric neurological and neurosurgical societies. Data collected included geographic region of practice, experience, responses to questions, and comments.

RESULTS

One hundred twenty-seven responses were evaluated (104 neurosurgeons and 23 neurologists, from 32 countries, across 6 continents). We found wide variations in the recommendations for management and lifestyle modification, with significant differences between regions of practice. Eighty percent recommend restrictions on physical activity, particularly for symptomatic and non-operated patients. Eighty-four percent prescribe aspirin. Sixty-five percent perform indirect revascularization. Seventy-eight percent recommend performing a staged surgery for bilateral MM. Only 26% perform acetazolamide challenge SPECT to evaluate brain perfusion. Only 15% of responders were from highly experienced centers.

CONCLUSION

This survey reflects the contemporary trends in management of pediatric MM, while highlighting the heterogeneity in the management approach of these patients. There is a need for multicenter, international studies to evaluate the safety, efficacy, and long-term outcome of various aspects of treatment of these patients.

A Retrospective Study of Neurological Complications in Pediatric Patients With Moyamoya Disease Undergoing General Anesthesia

BACKGROUND

Moyamoya disease is a condition with potentially devastating and permanent neurological sequelae. Adequate volume status and blood pressure, tight control of carbon dioxide to achieve normocarbia, and providing postoperative analgesia to prevent hyperventilation are typical goals that are used during anesthetic care in these patients. The purpose of this study was to assess postanesthesia neurological complications in moyamoya patients undergoing general anesthesia for imaging studies and surgical procedures excluding neurosurgical revascularization.

METHODS

We performed a retrospective cohort study examining moyamoya patients who received general anesthesia for imaging studies and nonneurosurgical-revascularization procedures between January 1, 2001 and December 1, 2016 at our quaternary care pediatric hospital. A general anesthetic encounter was excluded if it occurred within 30 days after a revascularization surgery. The electronic medical records of study patients were analyzed for perioperative management, and neurological outcomes within 30 days of an anesthetic were assessed.

RESULTS

A total of 58 patients undergoing 351 anesthesia exposures were included in the study. Three patients experienced neurological complications, which included focal neurological weakness, seizure, and altered mental status. The incidence of complications during anesthesia encounters was 0.85% (3/351) with a 95% confidence interval of 0.28-2.62.

CONCLUSIONS

Over a 16-year period at our hospital, 3 children with moyamoya disease who underwent anesthesia for nonneurosurgical-revascularization purposes demonstrated postanesthesia neurological symptoms. The symptoms were consistent with transient ischemic attacks and all resolved without long-term sequelae.

[Ischemic complications following surgical treatment of moyamoya disease: risk factors and prevention]

BACKGROUND

One of the most difficult problems in surgical treatment of moyamoya disease is prevention of ischemic perioperative complications. The risk of these events is significantly higher compared to other cerebrovascular diseases (up to 30%).

OBJECTIVE

To identify unfavorable prognostic factors of perioperative cerebral ischemic complications, to determine the group of high-risk patients and to develop the guidelines for perioperative management of these patients.

MATERIAL AND METHODS

We analyzed clinical and diagnostic data and postoperative outcomes in 80 patients with various forms of moyamoya disease. These patients underwent 134 different interventions. Staged revascularization of both hemispheres was performed in 40 patients (80 surgeries). Most patients (n = 55) underwent combined brain revascularization (79 surgeries).

RESULTS

Persistent postoperative complications (ischemic stroke) developed in 7 cases (5.3%). Transient neurological impairment was observed in 36 cases (27%). Statistical analysis revealed the following risk factors of perioperative complications: critical stenosis/occlusion of posterior cerebral artery (OR 9.704), severe perfusion deficit (OR 5.393) and previous TIA or ischemic stroke within 3 months prior to surgery (OR 6.433). If at least two of these signs are present, sensitivity of prognosis for postoperative complications is 80.7% and 88.6%, respectively.

CONCLUSION

Patients with moyamoya disease are at high risk of perioperative complications due to complex rearrangement of collateral cerebral circulation and high sensitivity of brain to local and systemic hemodynamic changes. Patients with risk factors require careful perioperative management to exclude pathogenetic factors provoking ischemia. Early surgical treatment is advisable to reduce the risk of ischemic and hemorrhagic lesions following natural course of disease and severe perioperative complications.

Postoperative Symptomatic Cerebral Infarction in Pediatric Moyamoya Disease: Risk Factors and Clinical Outcome

BACKGROUND

Indirect bypass surgery is used to improve the hemodynamic status of pediatric patients with moyamoya disease (MMD). Symptomatic cerebral infarction during the early postoperative period may be the most frustrating complication. This study was conducted to investigate the factors associated with early postoperative symptomatic cerebral infarction.

METHODS

Between January 2000 and February 2014, we performed 1241 indirect bypass surgeries in 659 pediatric MMD patients. Symptomatic infarction during the early postoperative period was diagnosed in 63 operations in 61 patients.

RESULTS

The overall incidence of symptomatic cerebral infarction after indirect bypass surgery was 5.1%. The median age of the patients with postoperative infarction was 6 years (mean, 6.4 years; range, 1-15 years). The performance of 2 craniotomies in single operation was associated with a higher rate of cerebral infarction. Moreover, the incidence was higher in young patients (age <6 years) compared with older patients. In a matched analysis, an immediate postoperative hemoglobin level >13 g/dL was associated with decreased risk of infarction (odds ratio, 0.144; P = 0.003). Mutation of the methylenetetrahydrofolate reductase (MTHFR) gene occurred in a relatively high proportion of our infarction cohort.

CONCLUSIONS

Postoperative symptomatic infarctions can occur despite a unified surgical method and formulaic perioperative management protocol. Patient-centered factors, such as young age, genetic background of MTHFR, and certain medical conditions, including hyperthyroidism, renovascular hypertension, and hemolytic uremic syndrome, as well as management-related factors, including 2 craniotomies and low immediate postoperative hemoglobin level, could be risk factors for early postoperative symptomatic cerebral infarction.

Evaluation of frequency-selective non-linear blending technique on brain CT in postoperative children with Moyamoya disease

OBJECTIVE

To evaluate whether a frequency-selective non-linear blending (BC) technique can improve tissue contrast and infarct detection on non-enhanced brain CT (NECT) in postoperative Moyamoya (MMD) patients.

MATERIALS AND METHODS

From January 2010 to December 2017, 33 children (13boys and 20girls; mean age 9.1±3.4 years) with MMD postoperatively underwent NECT followed by diffusion MRI. We compared the contrast-to-noise ratio (CNR) between gray matter (GM) and white matter (WM) in NECT and BC images and the CNR between the infarct lesion and adjacent normal-appearing brain in NECT and BC images using a paired t-test. We assessed image noise, GM-WM differentiation, artifacts, and overall quality using a Wilcoxon signed rank test. A McNemar two-tailed test was conducted to compare the diagnostic accuracy of infarct detection.

RESULTS

The CNR between GM and WM and the CNR of the infarct was better in BC images than in NECT images (3.9±1.0 vs. 1.8±0.6, P<0.001 and 3.6±0.3 vs. 1.9±0.2, P<0.001), with no difference in overall image quality observed. The sensitivity and specificity of infarct detection were 55.0% and 76.9% using NECT, and 70.0% and 69.2% using BC technique. The diagnostic accuracy of NECT and BC technique was 63.6% (21/33) and 69.7% (23/33), respectively.

CONCLUSION

This study showed that the BC technique improved CNR and maintained image quality. This technique may also be used to identify ischemic brain changes in postoperative MMD patients by improving the CNR of the infarct lesion.

Surgery for Moyamoya Disease in Children

Moyamoya disease is a chronic progressive cerebrovascular occlusive disease of the terminal portion of the internal carotid arteries associated with an acquired abnormal vascular network at the base of the brain, often leading to ischemic or hemorrhagic stroke. Moyamoya disease is a relatively common cause of pediatric stroke with a specific racial and well-identified clinical and imaging phenotype. Moyamoya disease is more prevalent in East Asian countries compared with other geographic regions with a higher incidence of familial cases and clinically more aggressive form. Moyamoya disease is one of the few causes of stroke that is amenable to effective surgical revascularization treatment. There are various surgical options available for revascularization, including the direct, indirect, or combined bypass techniques, each with variable responses. However, due to the heterogeneity of the diseases, different clinical course, geographical variables associated with the disease, and availability of a wide variety of surgical revascularization procedures, optimal selection of a surgical candidate and the surgical technique becomes challenging, particularly in the pediatric population. This brief review presents pertinent literature of clinical options for the diagnosis and surgical treatment of moyamoya disease in children.

Clinical Features, Surgical Treatment, and Long-Term Outcome of a Multicenter Cohort of Pediatric Moyamoya

Objective: This study aims to investigate the clinical features, long-term outcomes, and prognostic predictors of a multicenter cohort of children with moyamoya disease.

Methods: A series of 303 consecutive pediatric moyamoya disease (MMD) patients were screened in the present study. The clinical characteristics were retrospectively collected, and long-term outcomes was evaluated. Furthermore, logistic regression analyses were performed to determine the prognostic predictors for the clinical outcome.

Results: The mean onset age at diagnosis was 9.4 years old. The gender ratio (girl-to-boy ratio) was 1.1:1.0. Among these 303 patients, 13 patients underwent different surgical modalities in bilateral hemispheres, while eight patients failed to follow-up, and were excluded. Therefore, a total of 282 patients were analyzed. Among these patients, 17 patients underwent combined bypass (CB), 47 patients underwent direct bypass (DB), 150 patients underwent indirect bypass (IB), and 68 patients underwent conservative treatment. Furthermore, recurrent stroke events were observed in 35 patients (12.4%). The Kaplan-Meier analysis demonstrated that there was no significant difference in either ischemia or hemorrhage-free time among the different surgical modalities (P = 0.67 and 0.79, respectively). Furthermore, longer ischemia-free time was observed in the surgical group, when compared to the conservative group (P < 0.01). In addition, 82.7% (177/214) of patients who underwent surgical treatment obtained good outcomes (mRS 0-1), which were significantly higher than the rate of patients who underwent conservative treatment (52.9%, 36/68; P < 0.01). The rate of patients with improved symptoms was also significantly different (93.0 vs. 16.2%, P < 0.01). However, no significant difference was observed in the rate of good outcomes, disability, and improved symptoms among the different surgical modalities. The logistic regression analyses revealed that postoperative ischemic events were the only risk factor associated with unfavorable clinical outcome (OR:3.463; 95% CI:1.436–8.351; P < 0.01).

Conclusion: CB, DB, and IB might have similar effects on long-term clinical outcome in pediatric MMD. However, surgical revascularization is superior, when compared to conservative treatment. Furthermore, postoperative ischemic events were confirmed as potential prognostic factors associated with unfavorable clinical outcome.

Encephaloduroarteriosynangiosis for Pediatric Moyamoya Disease: A Single-Center Experience With 67 Cases in China

The purpose of this study is to investigate the surgical results and long-term outcomes of encephaloduroarteriosynangiosis for moyamoya disease in pediatric patients. We performed a retrospective analysis of 67 pediatric patients with moyamoya disease who underwent encephaloduroarteriosynangiosis in Beijing Tiantan Hospital. The case series included 36 boys and 31 girls. All the patients underwent surgical revascularization, and a total of 93 encephaloduroarteriosynangiosis procedures were performed (41 unilateral, 26 bilateral). The mean follow-up period after surgery was 30 months. During follow-up, ischemic stroke events were detected in 5 patients and the stroke rate for pediatric patients who underwent encephaloduroarteriosynangiosis procedure was 7.1% per patient-years. At the last follow-up, favorable outcomes (modified Rankin Scale score ≤ 2) were observed in 65 cases (97.0%). Our study suggests that long-term surgical outcome of encephaloduroarteriosynangiosis in pediatric moyamoya disease patients is satisfactory, and this technique has a positive impact on the prevention of stroke recurrence.

Moyamoya disease and syndromes: from genetics to clinical management

Moyamoya angiopathy is characterized by a progressive stenosis of the terminal portion of the internal carotid arteries and the development of a network of abnormal collateral vessels. This chronic cerebral angiopathy is observed in children and adults. It mainly leads to brain ischemic events in children, and to ischemic and hemorrhagic events in adults. This is a rare condition, with a marked prevalence gradient between Asian countries and Western countries. Two main nosological entities are identified. On the one hand, moyamoya disease corresponds to isolated moyamoya angiopathy, defined as being “idiopathic” according to the Guidelines of the Research Committee on the Pathology and Treatment of Spontaneous Occlusion of the Circle of Willis. This entity is probably multifactorial and polygenic in most patients. On the other hand, moyamoya syndrome is a moyamoya angiopathy associated with an underlying condition and forms a very heterogeneous group with various clinical presentations, various modes of inheritance, and a variable penetrance of the cerebrovascular phenotype. Diagnostic and evaluation techniques rely on magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) conventional angiography, and cerebral hemodynamics measurements. Revascularization surgery can be indicated, with several techniques. Characteristics of genetic moyamoya syndromes are presented, with a focus on recently reported mutations in BRCC3/MTCP1 and GUCY1A3 genes. Identification of the genes involved in moyamoya disease and several monogenic moyamoya syndromes unraveled different pathways involved in the development of this angiopathy. Studying genes and pathways involved in monogenic moyamoya syndromes may help to give insights into pathophysiological models and discover potential candidates for medical treatment strategies.

Clinical Features, Surgical Treatment, and Long-Term Outcome in Pediatric Patients with Moyamoya Disease in China

Background: There was few detailed demographic and clinical data about Chinese patients with moyamoya disease. Here we describe the clinical features, surgical treatment, and long-term outcome of pediatric patients with moyamoya disease at a single institution in China. Methods: Our cohort included 288 pediatric patients with moyamoya disease. The demographic and clinical characteristics were obtained by retrospective chart review and long-term outcome was evaluated using the stroke status. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for clinical outcome. The risk of subsequent stroke was determined using the Kaplan-Meier method. Results: The median age for the onset of symptoms was 8.0 years. The ratio of female to male patients was 1:1. Familial occurrence of moyamoya disease was 9.4%. The incidence of postoperative complications was 4.2%. Postoperative ischemic events were identified as predictors of unfavorable clinical outcome, while older age of symptom onset was associated with a favorable clinical outcome. The Kaplan-Meier estimate stroke risk was 5% in the first 2 years, and the 5-year-Kaplan-Meier risk of stroke was 9% after surgery for all patients treated with surgical revascularization. Overall, 86% of patients had an independent life with no significant disability. Conclusion: This long-term survey demonstrated that most surgically treated pediatric patients with MMD maintain good outcomes. Our results indicate that an early diagnosis and active intervention before the establishment of irreversible hemodynamic change are essential to achieve a favorable clinical outcome.

Patterns of cerebral ischemia in children with moyamoya

BACKGROUND

Moyamoya disease is characterized by progressive cerebrovascular stenosis with recurrent cerebral ischemic events. Transient ischemic attacks are often associated with hyperventilation in children with moyamoya, suggesting hypoperfusion rather than thrombotic vaso-occlusion as a prominent mechanism. The patterns of ischemia and severity of steno-occlusive disease in such children may elucidate these mechanisms.

METHODS

Children, 1 month to 18 years, with moyamoya, observed over 11 years were analyzed. A study neuroradiologist reviewed all presurgical neuroimaging. Ischemic injury was categorized into cortical, subcortical, and watershed infarction. Angiographic findings were staged using a standardized method.

RESULTS

Twenty children, 15 girls, median age 6.4 years, were included. All children had magnetic resonance imaging and angiography, and in 16, conventional angiography was available. All 40 hemispheres, in 20 children, were evaluated. The initial clinical presentation included neurological deficits in 17, recurrent transient ischemic attacks in 7, headache in 8, seizures in 8, and alteration in consciousness in 4 children. Infarcts were bilateral in 13 (65%) children (ischemia alone in 14, ischemic stroke with hemorrhagic transformation in two, and primary hemorrhage in two). Infarcts were cortical and/or subcortical in 13 (65%), both deep and cortical watershed in 11 (55%), and cortical watershed alone in 5 (25%) children. The predominant vascular territory involved was the middle cerebral artery. The internal carotid arterial system was involved in all, with stage IV being the most frequent angiographic stage.

CONCLUSIONS

Ischemic injury in deep watershed zones is common in childhood moyamoya and may reflect non-vaso-occlusive ischemic mechanisms. Location and severity of vascular involvement may correlate with various patterns of ischemic infarction in moyamoya disease and requires further study.

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

Object

Although combined direct and indirect anastomosis in patients with moyamoya disease immediately increases cerebral blood flow, the surgical procedure is more complex. Data pertinent to the postoperative complications associated with combined bypass are relatively scarce compared with those associated with indirect bypass. This study investigated the incidence and characteristics of postoperative stroke in combined bypass and compared them with those determined from a literature review to obtain data from a large population.

Methods

A total of 358 revascularization procedures in 236 patients were retrospectively assessed by reviewing clinical charts and radiological data. PubMed was searched for published studies on surgical treatment to determine the incidence of postoperative complications in a larger population.

Results

Seventeen instances of postoperative stroke were observed in 16 patients (4.7% per surgery, 95% CI 2.8%–7.5%). Postoperative stroke was more frequent (7.9% per surgery) in adults than in pediatric patients (1.7% per surgery, OR 4.07, 95% CI 1.12–14.7; p < 0.05). Acute progression of stenoocclusive changes were identified in the major cerebral arteries (anterior cerebral artery, n = 3; middle cerebral artery, n = 1; posterior cerebral artery, n = 2). The postoperative stroke rate was comparable with that (5.4%) determined from a literature search that included studies reporting more than 2000 direct/combined procedures. No differences in the stroke rates between the direct/combined and indirect procedures were found. In the literature review, direct/combined bypass was more often associated with excellent revascularization (angiographic opacification greater than two-thirds) than indirect bypass (p < 0.05).

Conclusions

This experience of 358 consecutive procedures is one of the largest series for which the postoperative stoke rate for direct/combined bypass performed with a unified strategy has been reported. A systematic review confirmed that the postoperative stroke rate for the direct/combined procedure was comparable to that for the indirect procedure.

Moyamoya disease, revascularisation surgery and anaesthetic considerations

We report a case of a rare disease that requires a unique anaesthetic approach for a unique surgical procedure. Anaesthesiologists need to be familiar with different pathophysiological aspects of this disease and its perioperative management.

Unpredictable postoperative global cerebral infarction in the patient of williams syndrome accompanying moyamoya disease

We report a rare case of Williams syndrome accompanying moyamoya disease in whom postoperative global cerebral infarction occurred unpredictably. Williams syndrome is an uncommon hereditary disorder associated with the connective tissue abnormalities and cardiovascular disease. To our knowledge, our case report is the second case of Williams syndrome accompanying moyamoya disease. A 9-year-old boy was presented with right hemiparesis after second operation for coarctation of aorta. He was diagnosed as having Williams syndrome at the age of 1 year. Brain MRI showed left cerebral cortical infarction, and angiography showed severe stenosis of bilateral internal carotid arteries and moyamoya vessels. To reduce the risk of furthermore cerebral infarction, we performed indirect anastomosis successfully. Postoperatively, the patient recovered well, but at postoperative third day, without any unusual predictive abnormal findings the patient's pupils were suddenly dilated. Brain CT showed the global cerebral infarction. Despite of vigorous treatment, the patient was not recovered and fell in brain death one week later. We suggest that in this kind of labile patient with Williams syndrome accompanying moyamoya disease, postoperative sedation should be done with more thorough strict patient monitoring than usual moyamoya patients. Also, we should decide the revascularization surgery more cautiously than usual moyamoya disease. The possibility of unpredictable postoperative ischemic complication should be kept in mind.

Electroencephalogram monitoring during intracranial surgery for moyamoya disease

We describe our experience with intraoperative electroencephalography in moyamoya surgery, a method to monitor for ischemic changes during the procedure and to minimize the risk of intraoperative and perioperative stroke. Case records and intraoperative electroencephalography recordings of all patients (n=220) treated with surgical revascularization for moyamoya (pial synangiosis) performed for 14 years (1994-2008) were reviewed. Electroencephalographic slowing occurred in 100 cases (45.5%), and was persistent in nine cases (9%). Slowing coincided with specific operative manipulations, most commonly while suturing the donor vessel to the pia, and during closure of the craniotomy. Slowing generally occurred bilaterally, independently of the side of intervention. The presence, length, and severity of slowing were not predictive of perioperative ischemic events. We present additional data on intraoperative electroencephalography with a modified montage to accommodate the craniotomy. Although not predictive of perioperative ischemic events in this series, electroencephalographic changes were correlated with specific operative interventions, and revealed global responses to unilateral manipulation. These findings suggest that prospective analyses of this technique may elucidate additional methods of predicting (and possibly preventing) perioperative ischemic events.

Pediatric moyamoya disease: An analysis of 410 consecutive cases

OBJECTIVE

Moyamoya disease (MMD) is a cerebrovascular occlusive disease of the bilateral internal carotid arteries that causes a compensatory abnormal vascular network at the base of brain. The rare incidence and various surgical techniques applied have limited the clinical research on MMD.

METHODS

We conducted a retrospective analysis of the surgical outcome of 410 pediatric MMD patients. All patients were treated in a relatively uniform scheme at a single institution. The surgical procedures consisted of bilateral encephaloduroarteriosynangiosis augmented by bifrontal encephalogaleo-/periosteal synangiosis. Logistic regression analyses were applied to reveal the prognostic factors for surgical outcome.

RESULTS

The overall clinical outcome was excellent in 66%, good in 15%, fair in 15%, and poor in 4% of the patients. Therefore, 81% of the patients had a favorable clinical outcome (excellent and good). Multivariate analyses revealed that infarction on presentation was associated with unfavorable clinical outcome (odds ratio [OR], 2.85; 95% confidence interval [CI], 1.49-5.46; p < 0.01) and decreased vascular reserve only on single-photon emission computerized tomography (OR, 0.07; 95% CI, 0.01-0.52; p < 0.01), with favorable clinical outcome.

INTERPRETATION

Our results indicate that an early diagnosis and active intervention before establishment of irreversible hemodynamic change are essential to achieve a favorable clinical outcome in children with MMD.

Effect of preoperative skull block on pediatric moyamoya disease

OBJECT

Stable hemodynamics, normocapnia, and adequate pain relief are considered important factors in the reduction of neurological complications in pediatric patients undergoing encephaloduroarteriomyosynangiosis (EDAMS) operations for the treatment of moyamoya disease. A preoperative skull block may reduce hemodynamic fluctuations and hypo- or hyperventilation due to emergence delirium or oversedation and provide adequate pain relief, thereby reducing postoperative morbidity.

METHODS

Pediatric patients (age 3-13 years) undergoing EDAMS surgery for moyamoya disease were randomly divided into a nerve block (NB) group (18 cases) or control group (21 cases). The treatment group patients received a preoperative NB (0.25% 5-8 ml bupivacaine mixed with 20-40 mg methylprednisolone) targeting the supraorbital, supratrochlear, auriculotemporal, and posterior auricular nerves. Patients in the control group did not receive NB. General anesthesia with sevoflurane was induced in both groups.

RESULTS

In the NB group, stable hemodynamic parameters were obtained with a lower sevoflurane concentration than in the control group. For delirious awakening, the odds ratio in the control group was 4.9 compared with the NB group. Pain and analgesic requirement were higher in the control patients than in the NB-treated patients during the postanesthesia care unit stay. However, the arterial CO(2) tension in the postanesthesia care unit did not differ between the 2 groups. The odds ratio in the control group for the rate of morbidity (cerebral infarction and reversible ischemic neurological deficits) during the first 24 hours following the operation was 3.2 compared with the NB group.

CONCLUSIONS

The use of skull block during EDAMS surgery provided easy hemodynamic control, calm awakening, and better pain relief and may be related to the reduced postoperative morbidity.

Nursing issues in caring for children with moyamoya vasculopathy and their families

Moyamoya vasculopathy is a rare, progressive neurovascular condition that may cause recurrent transient ischemic attacks, ischemic strokes, hemorrhagic strokes, or neurologic decline in children. Children with moyamoya disease have no clear contributing etiology, but children with moyamoya syndrome have contributory diagnoses such as Down syndrome or neurofibromatosis. The concerns and lived experiences of children affected by this disease and their families have not been well explored or addressed in the nursing literature. Nurses who understand this lived experience increase their own knowledge of the disease so they can manage the complex medical issues, educate families about the disease, and provide emotional support.

Hemorrhage predisposing to cerebral infarction in children with moyamoya disease

Two children with a new diagnosis of hemorrhagic type moyamoya disease experienced cerebral infarction after intraventricular hemorrhage. The patients developed ischemia 15 and 2 days after the initial diagnosis of hemorrhage. No provocative factor such as hypoperfusion was identified, but both patients exhibited signs of increased intracranial pressure on computed tomographic scan before infarction. Increased intracranial pressure in the setting of hemorrhage may be a risk factor for ischemic complications in patients with moyamoya disease. The optimal acute management of these patients requires further study.

Surgical management of moyamoya syndrome

Moyamoya syndrome, a vasculopathy characterized by chronic progressive stenosis at the apices of the intracranial internal carotid arteries, is an increasingly recognized entity which is associated with cerebral ischemia. Diagnosis is made on the basis of clinical and radiographic findings, including a characteristic stenosis of the internal carotid arteries in conjunction with abundant collateral vessel development. Adult moyamoya patients often present with hemorrhage, leading to rapid diagnosis. In contrast, children usually present with transient ischemic attacks or strokes, which may prove more difficult to diagnose because of patient's inadequate verbal and other skills, leading to delayed recognition of the underlying moyamoya. The progression of disease can be slow, with rare, intermittent events, or it can be fulminant, with rapid neurologic decline. However, regardless of the course, it is apparent that moyamoya syndrome, both in terms of arteriopathy and clinical symptoms, inevitably progresses in untreated patients. Surgery is generally recommended for the treatment of patients with recurrent or progressive cerebral ischemic events and associated reduced cerebral perfusion reserve. Many different operative techniques have been described, all with the main goal of preventing further ischemic injury by increasing collateral blood flow to hypoperfused areas of the cortex, using the external carotid circulation as a donor supply. This article discusses the various treatment approaches, with an emphasis on the use of pial synangiosis, a method of indirect revascularization. The use of pial synangiosis is a safe, effective, and durable method of cerebral revascularization in moyamoya syndrome and should be considered as a primary treatment for moyamoya, especially in the pediatric population.

Metabolic changes after H(2) 15O-positron emission tomography with acetazolamide in a patient with moyamoya disease: case report and review of previous cases

Perioperative ischemic complications not directly related to surgery require special attention in patients with moyamoya disease; positron emission tomography (H(2) 15O-PET) and single-photon emission computed tomography have been considered indispensable for evaluating pre- and postsurgical cerebral hemodynamics. The clinical records of 14 patients with moyamoya disease who underwent 26 extracranial-intracranial bypass operations were reviewed with special reference to perisurgical complications. One patient developed multiple postoperative ischemic infarctions and died of ischemic brain edema. The history of this patient with prolonged acidosis is analyzed, and the role of metabolic changes induced by H(2) 15O-PET with acetazolamide challenge is reviewed. Seven (77.8%) of nine patients operated on within 48 hours after H(2) 15O-PET with acetazolamide (group 1) developed metabolic acidosis, whereas only three (17.6%) of 17 patients operated on >48 hours (group 2) after the examination had intraoperative pH of <7.35. In group 1, the mean intraoperative pH was 7.328, which was significantly lower than the mean pH of 7.393 (P <.0001) in group 2. After H(2) 15O-PET with acetazolamide challenge, patients must be carefully observed concerning acidosis and volume state. We recommend at least 48 hours between examination and surgery for patients with moyamoya disease so that their conditions can stabilize. Furthermore, special care should be taken to avoid additional perioperative risk factors such as hypotension, hypocapnia, hypercapnia, and hypovolemia.

Surgical approaches to vascular anomalies of the child's brain

The population of pediatric patients with cerebrovascular disease presents a unique set of challenges to the neurosurgeon. The wide scope of pathology, including arteriovenous malformations, cavernous malformations and moyamoya disease, coupled with marked advances in diagnosis and treatment of these conditions over the past several years has resulted in a proliferation of the literature related to this subject. The present review provides an overview of current methods of surgical treatment for pediatric cerebrovascular diseases, focusing on indications and use of recent refinements of pre-existing surgical approaches, and newly evolved operative techniques developed to treat these entities.