Postoperative neurological deterioration following the revascularization surgery in children with moyamoya disease

Pediatric Moyamoya Revascularization Perioperative Care: A Modified Delphi Study

BACKGROUND

Surgical revascularization decreases the long-term risk of stroke in children with moyamoya arteriopathy but can be associated with an increased risk of stroke during the perioperative period. Evidence-based approaches to optimize perioperative management are limited and practice varies widely. Using a modified Delphi process, we sought to establish expert consensus on key components of the perioperative care of children with moyamoya undergoing indirect revascularization surgery and identify areas of equipoise to define future research priorities.

METHODS

Thirty neurologists, neurosurgeons, and intensivists practicing in North America with expertise in the management of pediatric moyamoya were invited to participate in a three-round, modified Delphi process consisting of a 138-item practice patterns survey, anonymous electronic evaluation of 88 consensus statements on a 5-point Likert scale, and a virtual group meeting during which statements were discussed, revised, and reassessed. Consensus was defined as ≥ 80% agreement or disagreement.

RESULTS

Thirty-nine statements regarding perioperative pediatric moyamoya care for indirect revascularization surgery reached consensus. Salient areas of consensus included the following: (1) children at a high risk for stroke and those with sickle cell disease should be preadmitted prior to indirect revascularization; (2) intravenous isotonic fluids should be administered in all patients for at least 4 h before and 24 h after surgery; (3) aspirin should not be discontinued in the immediate preoperative and postoperative periods; (4) arterial lines for blood pressure monitoring should be continued for at least 24 h after surgery and until active interventions to achieve blood pressure goals are not needed; (5) postoperative care should include hourly vital signs for at least 24 h, hourly neurologic assessments for at least 12 h, adequate pain control, maintaining normoxia and normothermia, and avoiding hypotension; and (6) intravenous fluid bolus administration should be considered the first-line intervention for new focal neurologic deficits following indirect revascularization surgery.

CONCLUSIONS

In the absence of data supporting specific care practices before and after indirect revascularization surgery in children with moyamoya, this Delphi process defined areas of consensus among neurosurgeons, neurologists, and intensivists with moyamoya expertise. Research priorities identified include determining the role of continuous electroencephalography in postoperative moyamoya care, optimal perioperative blood pressure and hemoglobin targets, and the role of supplemental oxygen for treatment of suspected postoperative ischemia.

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.

Clinical outcomes after revascularization for pediatric moyamoya disease and syndrome: A single-center series

Moyamoya is a progressive cerebrovascular arteriopathy that affects children of any age. The goal of this study was to determine imaging and clinical outcomes as well as complication rates in a pediatric cohort undergoing either a combined direct/indirect or indirect-only revascularization approach. Patients with moyamoya disease or syndrome ≤ 18 years of age at the time of initial surgery were identified, and clinical data were collected retrospectively. Over a 12-year period, 26 patients underwent revascularization procedures on 49 hemispheres with a median follow-up of 2.6 years from surgery. Median age at surgery was 7.3 years (range 1.4-18.0 years). Thirty-three hemispheres (67.3%) underwent combined revascularization with a direct bypass and encephalomyosynangiosis, and sixteen hemispheres (32.7%) underwent indirect-only revascularization. The rate of 30-day perioperative complication was 10.2%, and the rate of postoperative clinical stroke by end of follow-up was 10.2% by hemisphere. There was a 5.7% rate of intraoperative bypass failure requiring conversion to an indirect revascularization approach. On follow-up imaging, 96.9% of direct bypasses remained patent. On multivariate analysis, higher preoperative Pediatric Stroke Outcome Measure (PSOM) scores were associated with lower rates of good clinical outcome on follow-up (unit OR 0.03; p = 0.03). Patients with age < 5.4 years had lower rates of good clinical outcome on follow-up. In this North American cohort, both combined direct/indirect and indirect only revascularization techniques were feasible. However, younger children < 5.4 years of age have worse outcomes than older children, similar to east Asian cohorts.

Transient Intraoperative Central Diabetes Insipidus in Moyamoya Patients Undergoing Revascularization Surgery: A Mere Coincidence?

We present 2 patients with Moyamoya disease undergoing revascularization surgery who developed transient intraoperative central diabetes insipidus with spontaneous resolution in the immediate postoperative period. We speculate that patients with Moyamoya disease may be predisposed to a transient acute-on-chronic insult to the arginine vasopressin-producing portion of their hypothalamus mediated by anesthetic agents. We describe our management, discuss pertinent literature, and offer possible mechanisms of this transient insult. We hope to improve patient safety by raising awareness of this potentially catastrophic complication.

National Analysis of 2454 Pediatric Moyamoya Admissions and the Effect of Hospital Volume on Outcomes

BACKGROUND AND PURPOSE

Comprehensive multicenter data on treatment of pediatric moyamoya in the United States is lacking. We sought to identify national trends in the diagnosis and treatment of this disease.

METHODS

A total of 2454 moyamoya admissions from 1997 to 2012 were identified from the Kids Inpatient Database. Demographics, inpatient costs, interventions, and discharge status were analyzed. Admissions with and without surgical revascularization were reviewed separately. The effect of hospital moyamoya volume on outcomes was analyzed by multivariate regression analysis.

RESULTS

Care of moyamoya patients has been concentrating at high-volume centers during the past 12 years. Among moyamoya admission without surgical revascularization, high-volume hospitals show no difference in length of stay, cost, or complications compared with low-volume centers. However, low-volume hospitals have more nonroutine discharges (odds ratio, 2.32; P=0.0005) and inpatient deaths (odds ratio, 12.7; P=0.02) when no revascularization was performed. In contrast, among admissions with surgical revascularization, high-volume centers had decreased length of stay (4.7 versus 6.2 days; P=0.004), reduced cost ($88 000 versus $138 000; P<0.0001), and no increase in complications (P=0.29) compared with low-volume centers. Admissions with revascularization to low-volume hospitals also had increased likelihood of nonroutine discharge (odds ratio, 8.23; P=0.02) compared with high-volume centers.

CONCLUSIONS

This is the largest study of US pediatric moyamoya admissions to date. These data demonstrate that volume correlates with outcome, indicating high-volume centers provide significantly improved care and reduced mortality in pediatric moyamoya patients, with the most marked benefit observed in admissions for surgical revascularization.

Clinical implications of the cortical hyperintensity belt sign in fluid-attenuated inversion recovery images after bypass surgery for moyamoya disease

OBJECTIVE Transient neurological symptoms are frequently observed during the early postoperative period after direct bypass surgery for moyamoya disease. Abnormal signal changes in the cerebral cortex can be seen in postoperative MR images. The purpose of this study was to reveal the radiological features of the "cortical hyperintensity belt (CHB) sign" in postoperative FLAIR images and to verify its relationship to transient neurological events (TNEs) and regional cerebral blood flow (rCBF). METHODS A total of 141 hemispheres in 107 consecutive patients with moyamoya disease who had undergone direct bypass surgery were analyzed. In all cases, FLAIR images were obtained during postoperative days (PODs) 1-3 and during the chronic period (3.2 ± 1.13 months after surgery). The CHB sign was defined as an intraparenchymal high-intensity signal within the cortex of the surgically treated hemisphere with no infarction or hemorrhage present. The territory of the middle cerebral artery was divided into anterior and posterior parts, with the extent of the CHB sign in each part scored as 0 for none; 1 for presence in less than half of the part; and 2 for presence in more than half of the part. The sum of these scores provided the CHB score (0-4). TNEs were defined as reversible neurological deficits detected both objectively and subjectively. The rCBF was measured with SPECT using N-isopropyl-p-[¹²³I]iodoamphetamine before surgery and during PODs 1-3. The rCBF increase ratio was calculated by comparing the pre- and postoperative count activity. RESULTS Cortical hyperintensity belt signs were detected in 112 cases (79.4%) and all disappeared during the chronic period. Although all bypass grafts were anastomosed to the anterior part of the middle cerebral artery territory, CHB signs were much more pronounced in the posterior part (p < 0.0001). TNEs were observed in 86 cases (61.0%). Patients with TNEs showed significantly higher CHB scores than those without (2.31 ± 0.13 vs 1.24 ± 0.16, p < 0.0001). The CHB score, on the other hand, showed no relationship with the rCBF increase ratio (p = 0.775). In addition, the rCBF increase ratio did not differ between those patients with TNEs and those without (1.15 ± 0.033 vs 1.16 ± 0.037, p = 0.978). CONCLUSIONS The findings strongly suggest that the presence of the CHB sign during PODs 1-3 can be a predictor of TNEs after bypass surgery for moyamoya disease. On the other hand, presence of this sign appears to have no direct relationship with the postoperative local hyperperfusion phenomenon. Vasogenic edema can be hypothesized as the pathophysiology of the CHB sign, because the sign was transient and never accompanied by infarction in the present series.

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.

Multiple burr hole surgery as a treatment modality for pediatric moyamoya disease

Objective:

To re-emphasize that indirect revascularization surgery alone, where multiple burr holes and arachnoid openings are made over both cerebral hemispheres, is beneficial in the treatment of moyamoya disease (MMD) in children.

Clinical Presentation:

We report a 10-year-old boy who presented with complaints of episodic headache for the last 5 years. At the peak of his headache he had visual disturbances and acute onset weakness of left-sided limbs, recovering within a few minutes. He had no focal neurological deficits. Radiological investigations revealed abnormal findings, demonstrating the features of MMD.

Surgical Management:

He underwent bilateral multiple burr holes, dural and arachnoid opening over the frontal, parietal and temporal regions of each hemisphere. The elevated periosteal flap was placed in contact with the exposed brain through each burr hole.

Results:

On 6-months follow-up he had only one episode of transient ischemic attack. Postoperative four vessel angiogram demonstrated excellent cerebral revascularization around the burr hole sites, and single photon emission computerized tomography imaging showed hypoperfusion in the right temporo-occipital area suggestive of an old infarct with no other perfusion defect in the rest of the brain parenchyma.

Conclusion:

In children with MMD this relatively simple surgical technique is effective and safe, and can be used as the only treatment without supplementary revascularization procedures. This procedure can be done in a single stage on both sides and the number of burr holes made over each hemisphere depends on the extent of the disease.

Therapeutic hypothermia is associated with a decrease in urine output in acute stroke patients

AIMS

It is unclear what effect therapeutic hypothermia may have on renal function, because its effect has so far been primarily evaluated in settings in which there may be possible confounding perturbations in cardiovascular and renal physiology, such deep intraoperative hypothermia, general anesthesia, and post-cardiac arrest. We sought to determine if therapeutic hypothermia affects renal function in awake patients with normal renal function who were enrolled into a clinical trial of hypothermia plus intravenous thrombolysis for acute ischemic stroke.

METHODS

Eleven patients with normal renal function were cooled to 33°C for 24 h using an endovascular catheter, and then re-warmed over 12 h to 36.5°C, while hourly temperature, blood pressure, and fluid status data was recorded. Blood samples for blood urea nitrogen (BUN), creatinine, and hematocrit were drawn prior to treatment (baseline), immediately after hypothermia and re-warming (day 2), and again at day 7 or discharge, and values compared.

RESULTS

On initiation of cooling, temperatures dropped from a median pre-treatment value of 36.1°C (IQR: 35.8-36.4°C) to 33.1°C (IQR: 33.1-33.4°C). Urine output decreased 5.1 ml/h for every 1°C decrease in body temperature (p-value=0.001), with no associated serious adverse events. There were no statistically significant changes in BUN, creatinine, or hematocrit in the hypothermia patients.

CONCLUSION

Inducing hypothermia in patients with relatively unperturbed renal physiology results in a decrease in urine output that is linearly correlated with the decrease in core temperature. This has important implications for fluid management in patients undergoing therapeutic hypothermia.

Endovascular Management of Symptomatic Spasm of Radial Artery Bypass Graft

OBJECTIVE

To describe the technique of endovascular access for treatment of vasospasm of a radial artery bypass graft from the occipital artery to the M3 branch of the middle cerebral artery (MCA) in a patient with moyamoya disease.

CLINICAL PRESENTATION

A 32-year-old woman presented with recurrent right-sided ischemic symptoms in the territory of a previous stroke. Angiographic findings were consistent with moyamoya disease, and a perfusion deficit was identified on computed tomography (CT) perfusion imaging.

TECHNIQUE

The patient underwent a left MCA bypass graft for flow augmentation. She returned with an occluded bypass graft, collateralization of the anterior MCA territory through a spontaneous synangiosis, and a severe perfusion deficit in the posterior MCA territory. She underwent a revision bypass graft procedure with the radial artery from the occipital artery stump to the MCA-M3 branch. She developed repeated symptomatic vasospasm of the radial artery graft postoperatively. After systemic anticoagulation, the graft was accessed through the occipital artery, and intra-arterial verapamil was injected. When this failed to resolve the graft spasm, the radial artery graft was accessed with a 0.14-inch Synchro-2 microwire (Boston Scientific, Natick Massachusetts), and sequential angioplasties were performed using over-the-wire balloons from the proximal to distal anastomosis and in the occipital artery stump. A nitroglycerin patch was applied cutaneously over the graft to relieve the vasospasm.

RESULTS

No complications occurred. Graft patency with robust flow was observed on the 5-month follow-up angiogram.

CONCLUSION

Endovascular techniques can be safely used for salvage of spastic extracranial-intracranial grafts.

Pial synangiosis in patients with moyamoya syndrome and sickle cell anemia: perioperative management and surgical outcome

Object

Many children with sickle cell anemia (SCA) also have clinical and radiographic findings of an arteriopathy suggestive of moyamoya syndrome. These patients may continue to experience strokes despite optimal medical management. The authors wished to define features of moyamoya syndrome associated with SCA and determine the results of surgical revascularization in these patients at early and late follow-up.

Methods

The authors reviewed the clinical and radiographic records of all patients with moyamoya syndrome and SCA who underwent cerebral revascularization surgery using a standardized surgical procedure—pial synangiosis—from 1985 to 2008.

Results

Twelve patients had SCA and moyamoya syndrome. Six patients were female and 6 were male. The average patient age at surgery was 11.3 years (range 3–22 years). All patients presented with ischemic symptoms, 11 (92%) with previous transient ischemic attacks, and 10 (83%) with completed strokes. Eleven patients (92%) had radiographic evidence of previous stroke at presentation. None presented with hemorrhage. Surgical treatment included pial synangiosis in all patients. Complications included 1 perioperative stroke, 1 wound infection, and 1 perioperative pneumonia. The average length of hospital stay was 5.7 days (including a 24-hour preoperative admission for hydration) and average blood loss was 92.5 ml/hemisphere (in a total of 19 hemispheres). Clinical and radiographic follow-up with an average of 49 months (range 9–144 months) demonstrated no worsening in neurological status in any patient. No clinical or radiographic evidence of new infarcts was observed in any patient at late follow-up, despite disease progression in 13 (68%) of 19 hemispheres.

Conclusions

The clinical and radiographic features of moyamoya syndrome associated with SCA appear comparable to primary moyamoya disease. Successful treatment of these patients requires multidisciplinary care involving hematologists, anesthesiologists, and neurosurgeons. Operative treatment of moyamoya syndrome using pial synangiosis appears to be safe and confers long-lasting protection against further stroke in this population, and provides an alternative for failure of optimal medical therapy in patients. This study underscores the potential merit of screening patients with SCA for moyamoya syndrome.

Cerebral revascularization for ischemia, aneurysms, and cranial base tumors

This article extensively reviews the history, indications for bypass, choice of grafts, techniques, complications, and results after cerebral revascularization. The current role and future perspectives of cerebral revascularization are discussed. The results of 295 direct revascularization procedures in 285 patients (130 tumors and 115 aneurysms from 1988 to 2006; 40 cases of ischemia from 1994 to 2006) and 26 pial synangiosis procedures (for moyamoya syndrome in children from 1997 to 2007) have been summarized. Current operative techniques are illustrated with drawings and video clips.

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.

Multiple bur hole surgery for the treatment of moyamoya disease in children

OBJECT

The authors' aim in this study was to review their experience in the use of indirect revascularization alone in a series of 14 children with moyamoya disease, in which numerous bur holes and arachnoid openings were made over each affected hemisphere.

METHODS

Revascularization through multiple bur holes and arachnoid openings was performed in 14 children (mean age at diagnosis 6.5 years [range 3-15 years]) who suffered from progressive moyamoya disease. The authors performed surgery in a total of 24 hemispheres during 18 procedures. Ten children underwent bilateral multiple bur hole procedures, three underwent a unilateral procedure in the more severely affected hemisphere, and one child had previously undergone an encephaloduroarteriomyosynangiosis on the contralateral side. Ten to 24 bur holes were made in the frontotemporoparietooccipital area of each hemisphere, depending on the site and extent of the disease. Early postoperative perfusion magnetic resonance imaging studies, performed in the five most recent cases, showed restoration of cortical perfusion as early as 3 months, which was confirmed on subsequent angiography studies (performed between 8 and 12 months postoperatively) that showed excellent revascularization of the ischemic brain by external carotid artery collateral vessels. None of the children sustained further ischemic attacks postoperatively. Motor improvement was noted in those who had presented with paresis. A single seizure episode occurred in two patients at 2 weeks and 5 months after surgery; both children had presented with epilepsy. There were no postoperative deaths, and only one complication (an infected lumbar shunt in the patient who required cerebrospinal fluid [CSF] drainage). Five of the 18 procedures were complicated by subcutaneous CSF collections, which resolved with tapping and compressive head dressings; a transient lumbar drain was necessary in one case.

CONCLUSIONS

The results obtained in this series suggest that in children with moyamoya disease this simple technique is both effective and safe. Furthermore, it is effective as a sole treatment without supplementary revascularization procedures.

Anesthetic management of pial synangiosis and intracranial hemorrhage with a Fontan circulation

We report the case of a 11-year-old girl with Moyamoya syndrome, who had undergone staged-repair of tricuspid atresia to a Fontan circulation, scheduled to undergo bilateral pial synangiosis. Surgery for the first hemisphere was complicated by intracranial hemorrhage requiring an emergency craniotomy. The case highlights the importance of understanding Fontan physiology and its interrelationship with the cerebral circulation in the setting of cerebrovascular insufficiency and raised intracranial pressure.

Acute carotid arterial occlusion after burr hole surgery for chronic subdural haematoma in moyamoya disease

Ischaemic strokes and neurological deterioration have been described after revascularisation surgery in patients with moyamoya disease, but accelerated acute occlusion of the internal carotid artery after burr hole surgery has not been reported in this setting. A 66-year-old woman with known moyamoya disease who presented with right motor weakness underwent burr hole surgery for a bilateral chronic subdural haematoma. Postoperatively, the patient had a crescendo transient ischaemic attack and then deteriorated. Angiography showed complete occlusion of the left internal carotid artery. Burr hole surgery may cause postoperative acute occlusion of a preexisting stenotic artery in patients with moyamoya disease.

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.

Frontal lobe infarction due to hemodynamic change after surgical revascularization in moyamoya disease--two case reports

A 60-year-old female and a 40-year-old male underwent surgical revascularization for moyamoya disease and suffered small infarction in the ipsilateral frontal lobe 3 or 4 days postoperatively. Neuroimaging suggested that the bypass flow had caused rapid progression of occlusive changes in the carotid forks, a diminishing of moyamoya vessels, and flow reduction in the anterior cerebral artery ipsilateral to surgery, leading to critical ischemia in the frontal lobe. Surgical revascularization improves the outcome of patients with moyamoya disease, but postoperative management such as hydration is important to avoid ischemic complications due to frontal lobe infarction.

Monitoring and management of the paediatric neurosurgical patient

Head injury remains the most common cause of death in children, and tumours of the central nervous system are the most common solid tumour encountered. There is little class 1 evidence on which to base the monitoring and management of the paediatric patient with these conditions, management strategies commonly being extrapolated from those in use for adults. However, the clinical outcome for these conditions appears to be improving, with evidence suggesting that this improvement is being achieved by the management of these children in specialist centres.

Direct and combined revascularization in pediatric moyamoya disease

OBJECTIVE

Surgical revascularization of moyamoya disease can improve neurological outcomes, compared with the natural history of the disease or the results of medical treatment. Controversy exists regarding whether direct or indirect revascularization yields better outcomes. This study involves a single-center experience with direct anastomosis and is the first North American series using direct revascularization for pediatric patients with moyamoya disease.

METHODS

Twelve patients (age range, 5-17 yr; mean age, 10.2 yr) underwent direct revascularization of 21 hemispheres. Two patients had experienced failure of previous indirect revascularization procedures, with continued clinical deterioration. Superficial temporal artery-middle cerebral artery anastomosis was performed in 19 hemispheres (with concurrent encephaloduroarteriosynangiosis in 6). Middle meningeal artery-middle cerebral artery anastomosis and omental transposition were each performed in one hemisphere. Follow-up periods ranged from 12 to 65 months (mean, 35 mo), and monitoring included neurological examinations, angiography, magnetic resonance imaging, and cerebral blood flow studies.

RESULTS

The neurological conditions of all patients were stable or improved after surgery. None of the patients developed new strokes, and no new ischemic lesions were seen in magnetic resonance imaging scans. All grafts evaluated by follow-up angiography were patent. Postoperative cerebral blood flow studies showed significantly improved blood flow (54.4 versus 42.5 ml/100 g/min; P = 0.017, n = 4) and hemodynamic reserve (70.3 versus 43.9 ml/100 g/min; P = 0.009, n = 4), compared with preoperative studies.

CONCLUSION

Surgical revascularization by direct anastomosis in pediatric patients is technically feasible, is well tolerated, and can improve the progressive natural history, the angiographic appearance, and the cerebral blood flow abnormalities associated with the disease. Direct revascularization has the advantage of providing immediate and high-flow revascularization and is particularly useful for patients who have experienced failure of previous indirect revascularization procedures.