Cerebral revascularization using omental transplantation for childhood moyamoya disease

Omentomyelopexy for the Treatment of a Persistent Lumbar Pseudomeningocele: A Case Report With Technical Note

BACKGROUND AND IMPORTANCE

Pseudomeningoceles are extradural accumulations of cerebrospinal fluid. In most cases, they appear as a complication of spinal operations. Omentomyelopexy is a surgery in which an autologous omentum flap is implanted over the dural opening. We describe a case of persistent pseudomeningocele treated with omentomyelopexy.

CLINICAL PRESENTATION

A 37-year-old man sustained a T12-L1 AO B3 fracture during a motorcycle accident. He underwent posterolateral fusion and then neurological rehabilitation. Two years later, however, his condition worsened, and he experienced progressive weakness-he was diagnosed with an intramedullary cyst, which was treated with laminectomy, arachnolysis and cystotomy. A pseudomeningocele developed afterward, and the patient underwent multiple reoperations in the following years, none of which were effective. Omentomyelopexy, a complex procedure aimed to facilitate cerebrospinal fluid absorption and subsequent formation of a permanent membrane, was offered to the patient as a "last resort." After undergoing omentomyelopexy, his pseudomeningocele resolved.

CONCLUSION

Although it should be reserved for exceptionally pertinent cases, omentomyelopexy is a viable option for managing persistent pseudomeningocele. However, further research is needed to better understand the effects and benefits of omentomyelopexy in this context.

Posterior cerebral territory ischemia in pediatric moyamoya: Surgical techniques and long-term clinical and radiographic outcomes

PURPOSE

To describe a surgical technique for posterior cerebral revascularization in pediatric patients with moyamoya arteriopathy. Here, we describe the clinical characteristics, surgical indications, operative techniques, and clinical and radiographic outcomes in a series of pediatric patients with moyamoya disease affecting the posterior cerebral artery (PCA) territory.

METHODS

A retrospective single-center series of all pediatric patients with moyamoya disease who presented to our institute between July 2009 through August 2019 were reviewed. The clinical characteristics, surgical indications, operative techniques, and long-term clinical and radiographic outcomes of pediatric moyamoya patients with PCA territory ischemia were collected and analyzed.

RESULTS

A total of 10 PCA revascularization procedures were performed in 9 patients, 5 female, ages 1 to 11.1 years (average 5.2 years). Complications included 1 stroke, with no infections, hemorrhages, seizures, or deaths. One patient had less than 1 year of radiographic and clinical follow-up. In 8 of 9 patients with at least 1 year of radiographic follow-up, there was engraftment of surgical vessels present in all cases. No new strokes were identified on long-term follow-up despite the radiographic progression of the disease. In the 8 cases available for analysis, the average follow-up was 50.8 months with a range of 12 to 117 months.

CONCLUSIONS

PCA territory ischemia in patients with progressive moyamoya disease can be surgically treated with indirect revascularization. Here, we describe our experience with PCA revascularization procedures for moyamoya disease, including pial pericranial dural (PiPeD) revascularization and pial synangiosis utilizing the occipital artery. These surgical options may be useful for decreasing the risk of stroke in pediatric moyamoya patients with severe posterior circulation disease.

Adult Moyamoya Disease and Syndrome: Current Perspectives and Future Directions: A Scientific Statement From the American Heart Association/American Stroke Association

Adult moyamoya disease and syndrome are rare disorders with significant morbidity and mortality. A writing group of experts was selected to conduct a literature search, summarize the current knowledge on the topic, and provide a road map for future investigation. The document presents an update in the definitions of moyamoya disease and syndrome, modern methods for diagnosis, and updated information on pathophysiology, epidemiology, and both medical and surgical treatment. Despite recent advancements, there are still many unresolved questions about moyamoya disease and syndrome, including lack of unified diagnostic criteria, reliable biomarkers, better understanding of the underlying pathophysiology, and stronger evidence for treatment guidelines. To advance progress in this area, it is crucial to acknowledge the limitations and weaknesses of current studies and explore new approaches, which are outlined in this scientific statement for future research strategies.

Computational Modelling of Cerebral Blood Flow Rate at Different Stages of Moyamoya Disease in Adults and Children

Moyamoya disease is a cerebrovascular disorder which causes a decrease in the cerebral blood flow rate. In this study, a lumped parameter model describing the pressures and flow rates in the heart chambers, circulatory system, and cerebral circulation with the main arteries in the circle of Willis, pial circulation, cerebral capillaries, and veins was used to simulate Moyamoya disease with and without coarctation of the aorta in adults and children. Cerebral blood flow rates were 724 mL/min and 1072 mL/min in the healthy adult and child cardiovascular system models. The cerebral blood flow rates in the adult and child cardiovascular system models simulating Moyamoya disease were 676 mL/min and 1007 mL/min in stage 1, 627 mL/min and 892 mL/min in stage 2, 571 mL/min and 831 in stage 3, and 444 and 537 mL/min in stage 4. The cerebral blood flow rates were 926 mL/min and 1421 mL/min in the adult and child cardiovascular system models simulating coarctation of the aorta. Furthermore, the cerebral blood flow rates in the adult and child cardiovascular system model simulating Moyamoya disease with coarctation of the aorta were 867 mL/min and 1341 mL/min in stage 1, 806 mL/min and 1197 mL/min in stage 2, 735 mL/min and 1121 in stage 3, and 576 and 741 mL/min in stage 4. The numerical model utilised in this study can simulate the advancing stages of Moyamoya disease and evaluate the associated risks with Moyamoya disease.

Ten-year experience with laparoscopic pedicled omental flap for cerebral revascularization in patients with Moyamoya disease

BACKGROUND

The omental flap has numerous extraperitoneal applications in reconstruction and revascularization given its favorable immunologic and angiogenic properties. In patients with Moyamoya disease, cerebral revascularization using a pedicled omental flap has proven to be a viable option following direct revascularization procedures. Historically, harvesting omentum involved laparotomy with the associated risk of complications; herein we describe outcomes from a 10-year experience of laparoscopic harvesting of pedicled omental flap for cerebral revascularization in Moyamoya patients.

METHODS

A retrospective chart review was performed of all patients with Moyamoya disease who underwent laparoscopic omental cerebral transposition between 2011 and 2021. Intraoperative and postoperative complications, length of stay (LOS), and outcomes at follow-up were analyzed.

RESULTS

Twenty-one patients underwent the procedure during the study period. Three intraoperative complications occurred (one segmental transverse colectomy for mesenteric injury, one converted to omental free flap, and one requiring micro anastomosis). Average overall LOS was 6 ± 6 days, with 3 ± 3.5 days in the ICU (mean±SD). Following discharge, complications included epigastric incisional hernia at the graft fascial exit site, recurrent neck pain at subcutaneous tunneling site, and partial scalp necrosis. One patient required subsequent direct bypass seven months after the initial procedure owing to the progression of the disease. All other patients had partial or complete resolution of symptoms.

CONCLUSION

Our retrospective observational study indicates that laparoscopic pedicled omental flap mobilization and transposition is a safe and effective method of indirect cerebral revascularization in patients with Moyamoya disease.

LEVEL OF EVIDENCE

N/A.

Long-term clinical and radiographic outcomes after pial pericranial dural revascularization: a hybrid surgical technique for treatment of anterior cerebral territory ischemia in pediatric moyamoya disease

OBJECTIVE

Isolated anterior cerebral artery (ACA) territory ischemia in pediatric moyamoya disease (MMD) is rare but has been increasingly recognized, particularly in children manifesting progression of disease in a delayed fashion after middle cerebral artery revascularization surgery. Surgical treatment is complicated by limited graft choices, with the small number of case series largely focused on complex, higher-risk operations (omental flap transfers, large interhemispheric rotational grafts); direct bypass (often untenable in children due to vessel size); or, alternatively, the technically simpler method of multiple burr holes (of limited efficacy outside of infants). Faced with the problem of a growing cohort of pediatric patients with MMD that could benefit from anterior cerebral revascularization, the authors sought to develop a solution that was specifically designed for children and that would be lower risk than the more complex approaches adapted from adult populations but more effective than simple burr holes. In this study, the authors aimed to describe the long-term clinical and radiographic outcomes of a novel approach of pial pericranial dural (PiPeD) revascularization, building on the principles of pial synangiosis but unique in using the pericranium and the dura mater as the primary vascular supply, and employing a larger craniotomy with arachnoid dissection to provide robust full-territory revascularization in all ages with reduced risk relative to more complex procedures.

METHODS

The medical records of all pediatric patients with MMD who presented at a single center between July 2009 and August 2019 were retrospectively reviewed to identify patients with MMD with anterior cerebral territory ischemia. Clinical characteristics, surgical indications, operative techniques, and long-term clinical and radiographic follow-up data were collected and analyzed.

RESULTS

A total of 25 operations (5.6% of total procedures) were performed in 21 patients (mean age 9.4 years [range 1-16.5 years]; 12 female and 9 male). Almost one-third of the patients had syndromic associations, with no familial cases. Complications included 1 patient (4.7%) with a superficial infection, with no postoperative strokes, hemorrhage, seizures, or deaths. Long-term follow-up was available in 18 of 21 patients (mean 24.9 months [range 4-60 months]). Radiographic engraftment was present in 90.9% (20/22 hemispheres), and no new strokes were evident on MRI on long-term follow-up, despite radiographic progression of the disease.

CONCLUSIONS

The use of the pericranium and the dura mater for indirect revascularization provided robust vascularized graft with great flexibility in location and high potential for engraftment, which may obviate more complex and higher-risk operations for ACA territory ischemia. Long-term follow-up demonstrated that PiPeD revascularization conferred durable, long-term radiographic and clinical protection from stroke in pediatric patients with MMD. Based on the results of the current study, the PiPeD technique can be considered an additional tool to the armamentarium of indirect revascularization procedures in select pediatric patients with MMD.

The Top-100 most cited articles on Moyamoya disease: A bibliometric analysis

OBJECTIVE

Moyamoya disease (MMD) is a progressive steno-occlusive cerebrovascular phenomenon with unknown pathogenesis. Considering the abundance of articles addressing Moyamoya disease, a detailed analysis concerning the publication trends is of paramount importance. The aim of the study is to report the current knowledge of the top-100 most cited articles on Moyamoya disease in the literature.

METHODS

A non-time restricted keyword-based search was performed in June 2020 using the Scopus database. The search keywords included the following: "Moyamoya", "Moyamoya disease", and "Moyamoya syndrome". The search result was used to rank the articles based on their citation count. The top-100 most-cited articles were obtained and classified into seven categories.

RESULTS

A total of 3,543 articles on Moyamoya disease were published between 1955 and 2020. The Top-100 articles were published between 1977 and 2016 with a total of 16,119 citations, per year, and 7.23% rate of self-citation. The 1990s was the most productive decade (N=42). The most contributing country to the list was Japan (N=60). Stroke was the most active journal (N=23). Houkin, K., a Japanese neurosurgeon, was the most prolific author (N=15).

CONCLUSIONS

Moyamoya disease has been extensively investigated in the literature throughout the years. The majority of articles published in the literature were addressing the surgical management and clinical outcome. Authors from neurosurgical backgrounds were the most active contributors to the field of Moyamoya disease.

Surgical revascularization of frontal areas in pediatric Moyamoya vasculopathy: a systematic review

INTRODUCTION

The aim of this study is to systematically review the literature on surgical revascularization techniques for flow-augmentation of the frontal areas and/or anterior cerebral artery (ACA) territory in children with Moyamoya vasculopathy (MMV), to elucidate the current surgical practice and describe the outcome associated to the different techniques.

EVIDENCE ACQUISITION

The systematic review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. MEDLINE, Web of Science and EMBASE were searched up to April 2020. Published techniques were systematically analyzed according to level of evidence, revascularization technique, opening of the interhemispheric fissure (IF), uni- or bilateral revascularization, clinical, neurocognitive, angiographic, perfusion and hemodynamic outcome.

EVIDENCE SYNTHESIS

Twenty-five studies were enrolled, including 829 patients: among these, 13 patients underwent direct revascularization of ACA territories, 570 indirect revascularization and 246 patients combined revascularization. One study reached a level of evidence II (grade of recommendation B), 8 studies were level III (grade B) and 16 studies were level IV (grade C). The surgical techniques proposed in the enrolled papers were systematically described.

CONCLUSIONS

Combined techniques (grade of recommendation B) and indirect techniques (grade of recommendation C) are considered effective for revascularizing the frontal areas and/or anterior cerebral artery (ACA) territory in children with MMV. While performing the revascularization, surgical risks can be reduced by avoiding the exposure of the superior sagittal sinus and opening of IF (recommendation grade C). There is not sufficient evidence to define which type of surgical technique should be preferred. Future studies are needed for a longitudinal assessment of comparable outcomes and to determine which revascularization technique for the frontal areas and/or ACA territory is optimal for this highly specific pediatric population.

LC-QTOF-MS and 1H NMR Metabolomics Verifies Potential Use of Greater Omentum for Klebsiella pneumoniae Biofilm Eradication in Rats

Bacterial wound infections are a common problem associated with surgical interventions. In particular, biofilm-forming bacteria are hard to eradicate, and alternative methods of treatment based on covering wounds with vascularized flaps of tissue are being developed. The greater omentum is a complex organ covering the intestines in the abdomen, which support wound recovery following surgical procedures and exhibit natural antimicrobial activity that could improve biofilm eradication. We investigated changes in rats’ metabolome following Klebsiella pneumoniae infections, as well as the greater omentum’s ability for Klebsiella pneumoniae biofilm eradication. Rats received either sterile implants or implants covered with Klebsiella pneumoniae biofilm (placed in the peritoneum or greater omentum). Metabolic profiles were monitored at days 0, 2, and 5 after surgery using combined proton nuclear magnetic resonance (¹H NMR) and high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC–QTOF-MS) measurements of urine samples followed by chemometric analysis. Obtained results indicated that grafting of the sterile implant to the greater omentum did not cause major disturbances in rats’ metabolism, whereas the sterile implant located in the peritoneum triggered metabolic perturbations related to tricarboxylic acid (TCA) cycle, as well as choline, tryptophan, and hippurate metabolism. Presence of implants colonized with Klebsiella pneumoniae biofilm resulted in similar levels of metabolic perturbations in both locations. Our findings confirmed that surgical procedures utilizing the greater omentum may have a practical use in wound healing and tissue regeneration in the future.

Omentum a powerful biological source in regenerative surgery

The Omentum is a large flat adipose tissue layer nestling on the surface of the intra-peritoneal organs. Besides fat storage, omentum has key biological functions in immune-regulation and tissue regeneration.

Omentum biological properties include neovascularization, haemostasis, tissue healing and regeneration and as an in vivo incubator for cells and tissue cultivation. Some of these properties have long been noted in surgical practice and used empirically in several procedures.

In this review article, the author tries to highlight the omentum biological properties and their application in regenerative surgery procedures. Further, he has started a process of standardisation of basic biological principles to pave the way for future surgical practice.

Sternocleidomastoid Encephalomyosynangiosis for Treatment-Resistant Moyamoya Disease

BACKGROUND AND IMPORTANCE

Refractory ischemic symptoms in moyamoya disease are a challenging problem, particularly in situations in which multiple direct and indirect revascularization techniques have already been employed. In addition, revascularization of the parietal lobes is difficult, as this area is a watershed between the middle cerebral artery and posterior cerebral artery distributions.

CLINICAL PRESENTATION

This is the case of a 50-yr-old woman with hemibody sensorimotor deficits, who had previously undergone bilateral arterial bypass and temporalis myosynangiosis. A method for indirect surgical cerebral revascularization is described, utilizing a rotated and tunneled sternocleidomastoid flap. The perfused muscle is approximated to the cortical surface, with adjacent sulci dissected to expose the underlying vasculature. After sternocleidomastoid encephalomyosynangiosis, the patient experienced symptomatic improvement, along with the appearance of new pial collateral vasculature on diagnostic cerebral angiography. Pre- and postoperative dynamic perfusion computed tomography with acetazolamide challenge demonstrate an increase in cerebral blood flow and decrease in mean transit time, as well as improved cerebrovascular reserve.

CONCLUSION

Sternocleidomastoid encephalomyosynangiosis using a tunneled muscle flap is a useful method for revascularization of the parietal and occipital lobes, particularly for refractory moyamoya in cases where a variety of other options have been exhausted.

Indirect revascularization with the dural inversion technique for pediatric moyamoya disease: 20-year experience

OBJECTIVENumerous surgical procedures facilitate revascularization of the ischemic brain in patients with moyamoya disease. Dural inversion is a technique in which flaps of dura mater centered around the middle meningeal artery are inverted, encouraging the formation of a rich collateral blood supply. This procedure has been used in combination with encephaloduroarteriosynangiosis for more than 20 years at the authors' institution for the treatment of pediatric moyamoya disease. The objective of this study was to describe the clinical and radiographic outcomes for a cohort of consecutive pediatric moyamoya patients undergoing dural inversion.METHODSClinical and radiographic data on patients who had undergone dural inversion in the period from 1997 to 2016 were reviewed. Univariate and multivariate logistic regression and Kaplan-Meier analyses were performed to assess the risk of postoperative stroke, functional outcome, and the angiographic degree of revascularization.RESULTSDural inversion was performed on 169 hemispheres in 102 patients. Median follow-up was 4.3 years. Six patients (3.6% of hemispheres) suffered postoperative ischemic or hemorrhagic stroke. Overall mortality was 1.0%. Good postoperative neurological status (modified Rankin Scale [mRS] score ≤ 2) was observed in 90 patients (88%); preoperative and postoperative mRS scores showed significant improvement (p < 0.001). Eighty-six percent of hemispheres had Matsushima grade A or B revascularization. Younger age was associated with postoperative stroke and poor functional outcome. Patients with secondary moyamoya syndrome had a significantly worse radiographic outcome. The cumulative 5-year Kaplan-Meier risk for stroke was 6.4%.CONCLUSIONSDural inversion is a useful technique of cerebral revascularization in pediatric moyamoya disease. A 20-year experience demonstrates the safety and efficacy of this technique with a relatively low rate of postoperative stroke, good functional outcomes, and favorable angiographic results.

Strategies for and Outcome of Repeat Revascularization Surgery for Moyamoya Disease: An American Institutional Series

BACKGROUND

Revascularization for moyamoya disease (MMD) effectively prevents future ischemic events. However, small subsets of patients with persistent or new symptoms due to inadequate collateralization require repeat revascularizations.

OBJECTIVE

To investigate the clinical and radiological outcome of repeat revascularization in MMD patients with previous indirect or direct bypasses.

METHODS

Single institution, retrospective analysis of a prospective MMD database.

RESULTS

From 1991 to 2014, this institution performed 1244 revascularization bypasses (1107 direct, 137 indirect) in 765 patients, of whom 57 were repeat revascularizations (38 indirect, 19 direct bypass). When initially performed at the institution, the repeat revascularization rate was 4% for indirect and 1% for direct bypasses (P = .03). Cohorts with previous indirect vs direct bypass were slightly younger (mean age 23 vs 30 yr), with fewer females (61% vs 84%, P = .08), and a similar mean duration between initial bypass and repeat revascularization (49 vs 47 mo). Both groups had similar repeat revascularization due to transient ischemic attacks (66% vs 63%). One acute graft occlusion in the previous direct bypass group was revised within 1 wk postoperatively. Over 50% of the repeat revascularizations in both groups were direct bypasses; the major difference being that the repeat bypass in the direct group was to augment another vascular territory. At nearly 5 yr mean follow-up, over 80% of patients in both groups are well, free from stroke/transient ischemic attack symptoms, with excellent radiological results.

CONCLUSION

Repeat revascularization can safely and effectively prevent future ischemic events. Indirect bypass has a higher rate of repeat revascularization than direct bypass.

Magnetic Resonance Imaging (MRI) and Digital Subtraction Angiography Investigation of Childhood Moyamoya Disease

Because digital subtraction angiography (DSA) is not an ideal angiographic examination for moyamoya disease in the pediatric population, magnetic resonance angiography (MRA) provides a noninvasive contrast-free angiographic examination; whereas magnetic resonance imaging (MRI) provides superior spatial resolution and soft-tissue contrast for lesion assessment. Ninety patients with moyamoya disease were examined by MRI and DSA to assess the distribution of lesions and their diagnostic agreement between modalities. MRI examination revealed 439 lesions. Punctate lesions were the most abundant, followed by patchy lesions. These lesions generally covered a smaller area than the abnormal-vascular corresponding brain parenchyma. Steno-occlusive changes at bilateral anterior, medial, and posterior cerebral arteries were identified by MRA and DSA. MRI showed moderate agreement in identifying lesions after steno-occlusive changes in anterior and medial cerebral arteries, and good agreement in posterior cerebral arteries; 6% to 11% of cases were misdiagnosed by MRA.

Successful Laparoscopic Harvesting of Omental Pedicle Flap for Salvage Cerebral Revascularization in 2 Adults With Moyamoya Disease: Technique and Lessons Learned

Moyamoya is an idiopathic and progressive disease that leads to occlusion of intracranial arteries. When other methods of revascularization fail, omentum can be used as an indirect bypass to improve cerebral perfusion. Laparoscopic mobilization of a pedicled omental flap with subcutaneous tunneling to the brain has been described in small case series in children. We report our techniques and outcomes in 2 adults with Moyamoya to undergo such a procedure. An omental flap based on the right gastroepiploic artery was created and intraoperative fluorescence imaging using indocyanine green was used to assess the viability of the flap and to guide lengthening of the pedicle. The flap was tunneled subcutaneously using skip incisions. There were no intraoperative complications and no postoperative complications related to the omental flap. Follow-up evaluation demonstrates viable omental flaps and improved cerebral vascularization. This technique is feasible in adults who require salvage cerebral revascularization for Moyamoya disease.

Assessment of the cortical artery using computed tomography angiography for bypass surgery in moyamoya disease

Computed tomography angiography (CTA) is often used to assess the vascular status in moyamoya disease. The purpose of the study is to identify the characteristics of cortical arteries (M4) of moyamoya disease on CTA; the clinical significance of which is also discussed. A total of 38 hemispheric sides of 27 patients with moyamoya disease were included in this study. The number of M4 was visualized on CTA using cortical surface imaging and compared between the moyamoya disease group and the non-moyamoya disease group or the control group. Then, the clinical and radiological factors associated with the number of M4, the distribution of M4, and collateral circulation were examined. The number of M4 was lower in the moyamoya disease group than in the non-moyamoya disease group and in the control group (p < 0.05). There are few predictive clinical factors of the number of M4 except male sex. The prefrontal artery, precentral artery, central artery, and angular artery had a significantly higher prevalence in moyamoya disease (p < 0.05). The durocortical and periventricular anastomosis had a significantly higher prevalence in moyamoya disease (p < 0.05). The prevalence and distribution pattern of cortical arteries in moyamoya disease differed from that of the non-moyamoya disease group, and the distribution patterns of M4 might be influenced by collateral circulation. It is thus essential to recognize M4 to assess the recipient artery so as to ensure superficial temporal artery-middle cerebral artery bypass.

Laparoscopic harvesting of omental pedicle flap for cerebral revascularization in children with moyamoya disease

INTRODUCTION

An abundance of angiogenic and immunologic factors makes the omentum an ideal tissue for reconstruction and revascularization of a variety of extraperitoneal wounds and defects. Omental harvesting was historically performed through a large laparotomy and subcutaneous tunneling to the site of disease. Several complications of the open procedure including abdominal wound infection, fascial dehiscence, ventral hernia, and postoperative ileus have been described. The use of laparoscopy to harvest the omentum has the potential to reduce such complications. We describe the surgical technique and outcomes of a series of patients undergoing laparoscopic pedicled omental flap mobilization for cerebral revascularization in moyamoya disease.

METHODS

A retrospective chart review of all patients undergoing laparoscopic omental cerebral transposition for moyamoya disease between 2011 and 2014 was performed. Clinical indication, surgical technique, operative times, complications, and outcomes at follow-up were reviewed.

RESULTS

A total of 7 children underwent the procedure. The general surgery team performed laparoscopic omental mobilization, extraperitonealization, and subcutaneous tunneling, while the neurosurgical team performed craniotomy and cerebral application of the graft. The patients were followed postoperatively with clinic visits and angiography. There was one intraoperative complication (colon injury) and one postoperative complication (intermittent omental hernia at fascial defect for pedicle). All patients had partial to complete symptomatic resolution and demonstrated adequate intracranial revascularization on angiography.

CONCLUSION

Laparoscopic omental pedicle flap mobilization and subcutaneous transposition is feasible in children who require salvage cerebral revascularization for moyamoya disease. The procedure should be considered for other conditions requiring extraperitoneal revascularization.

Omental Approach to Functional Recovery After Cerebrovascular Disease

OBJECTIVE

To review and synthesize the clinical literature regarding risks and benefits of omentum transplantation and transposition surgery in patients with ischemic stroke of other etiology (non-MMD) and Moyamoya disease (MMD), and to evaluate the evidence for biological underpinnings of the presumed physiologic effects of omentum transplantation and transposition on vascularization of brain parenchyma.

METHODS

Articles were searched on scientific databases using predefined key terms. Data abstraction was based on the clinical course as reported in the articles. For further analysis, patients were divided into groups according to their diagnosis (MMD or non-MMD). Descriptive statistics were computed for better integration of the results.

RESULTS

The final literature review contained 15 articles (11 case series, 4 single case studies) with data on 93 patients (29 non-MMD, 64 MMD). At post-assessment 56% of patients showed substantial gains in functional domains (24% in the non-MMD group, 71% in the MMD group) and 92% demonstrated improvements of cerebral vascularization (55% in the non-MMD group, 98% in the MMD group). Differences in improvement became apparent with regard to the initial symptomatology wherein transient ischemic attacks were related to superior recovery rates and language pathologies showed least improvement.

CONCLUSIONS

Surgical revascularization using omental tissue has shown good success rates, particularly for recurrent transient ischemic attacks and prevention of further strokes and should be considered as treatment option for selected patients. Experimental data on the physiologic basis for postoperative improvement delivered convincing evidence for its arteriogenic potential and recent developments in omental stem cell research suggest a role in recovery from long-standing neurological deficits.

Radial Artery Grafts as Rescue Strategy for Patients with Moyamoya Disease for Whom Conventional Revascularization Failed

BACKGROUND

Failure of direct revascularization with superficial temporal artery (STA)-middle cerebral artery (MCA) bypass for Moyamoya disease (MMD) is comparatively rare. However, for those cases where a bypass fails to prevent further ischemic attacks, safe and efficient rescue strategies are needed. We present our experience with radial artery grafts for secondary revascularization of MMD.

METHODS

Between April 2007 and April 2014, we have performed STA-MCA bypass in 182 patients diagnosed with Moyamoya vasculopathy. Four patients with typical MMD who had an unsuccessful STA-MCA bypass required additional revascularization because they remained symptomatic. Digital subtraction angiography revealed delayed STA graft failure in these patients, who continued to have transient ischemic attacks after the initial surgery. Cerebral blood flow studies confirmed persistent impairment of cerebrovascular reserve capacity. As an escape strategy, we performed radial artery graft bypass surgery from the external carotid artery to the M2 or M3 portion of the MCA.

RESULTS

The median duration between the 2 surgeries was 10 months. The mean follow-up period after rescue revascularization was 8.5 ± 3.3 months. Revascularization with the radial artery graft was successful in all cases without perioperative complications. Postoperatively, none of the patients experienced further cerebrovascular events. After 3 months, digital subtraction angiography revealed patent radial artery grafts and adequate revascularization in 3 patients; 1 patient presented with bypass graft failure but had developed transdural collateral vessels contributing to the filling of the cerebral vasculature.

CONCLUSIONS

Rescue bypass with a radial artery graft provides a useful function. Although delayed graft failure may occur, this procedure is successful if the patients remain symptom free with the development of collateral flow.

Less invasive pedicled omental-cranial transposition in pediatric patients with moyamoya disease and failed prior revascularization

BACKGROUND

Patients with moyamoya disease and progressive neurological deterioration despite previous revascularization pose a major treatment challenge. Many have exhausted typical sources for bypass or have ischemia in areas that are difficult to reach with an indirect pedicled flap. Omental-cranial transposition has been an effective, but sparingly used technique because of its associated morbidity.

OBJECTIVE

We have refined a laparoscopic method of harvesting an omental flap that preserves its gastroepiploic arterial supply.

METHODS

The pedicled omentum can be lengthened as needed by dividing it between the vascular arcades. It is transposed to the brain via skip incisions. The flap can be trimmed or stretched to cover ischemic areas of the brain. The cranial exposure is performed in parallel with pediatric surgeons. We performed this technique in 3 pediatric patients with moyamoya disease (aged 5-12 years) with previous superficial temporal artery to middle cerebral artery bypasses and progressive ischemic symptoms. In 1 patient, we transposed omentum to both hemispheres.

RESULTS

Blood loss ranged from 75 to 250 mL. After surgery, patients immediately tolerated a diet and were discharged in 3 to 5 days. The ischemic symptoms of all 3 children resolved within 3 months postoperatively. Magnetic resonance imaging at 1 year showed improved perfusion and no new infarcts. Angiography showed excellent revascularization of targeted areas and patency of the donor gastroepiploic artery.

CONCLUSION

Laparoscopic omental harvest for cranial-omental transposition can be performed efficiently and safely. Patients with moyamoya disease appear to tolerate this technique much better than laparotomy. With this method, we can achieve excellent angiographic revascularization and resolution of ischemic symptoms.

Incidence of late cerebrovascular events after direct bypass among children with moyamoya disease: a descriptive longitudinal study at a single center

BACKGROUND

The potential for late cerebrovascular events following surgical revascularization presents a challenge in the treatment of pediatric moyamoya disease. Limited information is available on the incidence of such events after direct bypass. The objective of this descriptive study was to examine the incidence of late cerebrovascular events after direct bypass for pediatric moyamoya disease.

METHODS

The study cohort comprised consecutive patients with moyamoya disease who had undergone direct bypass at less than 18 years of age in the authors' institute between 1978 and 2003. They were prospectively followed until the end of the study period or, if applicable, the time of death.

RESULTS

Fifty-six of 58 enrolled patients (96.6%) were followed for a mean period of 18.1 years. Four patients experienced late cerebrovascular events, comprising one stroke and three hemorrhages, an average of 13 years after surgery, one of whom experienced a fatal second hemorrhage. The only late ischemic stroke in the cohort occurred after a severe head injury and emergent craniotomy. The incidence of late cerebrovascular events was 0.41% per year (95% confidence interval, 0.15-1.08); 10-year, 20-year, and 30-year cumulative incidences were 1.8%, 7.3%, and 13.1%, respectively.

CONCLUSIONS

Despite the efficacy of surgical revascularization, pediatric patients remain at risk of future cerebrovascular events, especially hemorrhage, after reaching adulthood and thus require careful long-term follow-up.

Thirteen-year Experience of 44 Patients with Adult Hemorrhagic Moyamoya Disease from a Single Institution: Clinical Analysis by Management Modality

Our objective was a retrospective assessment of the management modalities that provided the most beneficial treatment in hemorrhagic moyamoya disease during the last 13 years at our institution. The clinical results of 44 patients with hemorrhagic moyamoya disease were investigated, comparing revascularization surgery (direct, indirect, and combined bypass) or conservative treatment. Angiographic features, rebleeding, and clinical outcome were investigated. Six of the 35 patients (17.1%) with revascularization surgery experienced rebleeding, as did 4 of 9 patients (44.4%) with conservative treatment. However, patients who underwent bypass surgery had a lower chance of rebleeding. No significant difference in chance of rebleeding was observed between bypass surgery and non surgery groups (p > 0.05). Cerebral angiography performed after bypass surgery showed that for achieving good postoperative revascularization, direct and combined bypass methods were much more effective (p < 0.05). While the risk of rebleeding in the revascularization group was generally lower than in the conservative treatment group, there was no statistically significant difference between treatment modalities and conservative treatment. Although statistical significance was not attained, direct and combined bypass may reduce the risk of hemorrhage more effectively than indirect bypass.

The evolution of omentum transposition: from lymphedema to spinal cord, stroke and Alzheimer's disease

It is now well established that the omentum incorporates into its tissues a variety of biological factors that exert a favorable effect on the central nervous system. Physiological characteristics of the omentum include edema absorption, fibrotic inhibition, blood-brain barrier penetration and, of major importance, angiogenic activity. Over several decades, studies have shown increasing clinical uses of the omentum following its placement on various structures within the body. This paper details the evolution of omental transposition (OT) up to the present at which time OT is being applied to the brain of Alzheimer disease (AD) patients. Success in this area raises the possibility that the omentum may prove to be a present-day treatment for patients with AD until future pharmaceutical and/or genetic forms of treatment are developed.

Outcome of repeat revascularization surgery for moyamoya disease after an unsuccessful indirect revascularization

Object

Revascularization for moyamoya disease, either by direct anastomosis or indirect procedures, is an accepted and effective form of treatment for prevention of future ischemic events. Indirect procedures do not provide sufficient collateral vessels in a subset of patients, who then have persistent or new symptoms. Repeat revascularization procedures may be recommended for these patients.

Methods

Sixteen patients underwent repeat revascularization after undergoing an indirect procedure in the same hemisphere. These patients were included in the study, and a retrospective review of their clinical details, neuroimaging results, surgical details, and outcome was performed. Direct revascularization was the procedure of choice; however, in patients with no acceptable recipient vessel (> 0.6 mm) the authors added a second indirect procedure for further revascularization.

Results

Over the last 19 years, 16 patients (8 male and 8 female patients, age range 5–48 years, mean 16.7 years, 10 pediatric and 6 adult patients) underwent repeat revascularization for moyamoya disease. Initially all patients presented with ischemic symptoms (4 transient ischemic attacks [TIAs] and 12 strokes; 2 patients had bilateral symptoms). Angiography revealed that 13 patients had bilateral disease, and 3 had unilateral disease. Initial surgery was bilateral encephaloduroarteriosynangiosis (EDAS) in 9, unilateral EDAS alone in 3, unilateral EDAS with contralateral superficial temporal artery–middle cerebral artery (STA-MCA) bypass in 2, bilateral encephalomyosynangiosis (EMS) in 1, and unilateral EMS in 1. Thirteen of the 16 patients continued to have TIAs in the hemisphere ipsilateral to surgery, whereas 1 patient had seizures and cognitive deficit, 1 had asymptomatic infarct on MR imaging, and 1 had visual symptoms. Poor revascularization was seen on angiography studies in all patients. The median duration between the surgeries was 24 months (3 months–10 years).

Repeat revascularization was performed in 23 hemispheres (16 patients). Direct revascularization was performed in 14 hemispheres (60.9%): STA-MCA bypass in 10, external carotid artery–MCA vein bypass in 2, occipital artery (OA)–MCA in 1, and OA–posterior cerebral artery in 1 hemisphere. Indirect revascularization was performed for patients without an acceptable recipient vessel, and was done in 9 hemispheres. The procedures included EMS (4 hemispheres), repeat EDAS (2), and omental transposition (3). There was 1 postoperative death in a patient undergoing a high-flow vein graft implantation. None of the other patients experienced any neurological worsening after surgery.

Follow-up was available in all patients, ranging from 3 to 144 months (mean 34 months, median 12 months). Of the 15 patients who survived repeat revascularization surgery, 12 (80%) were free from any TIA, stroke, or any other neurological symptoms. Two patients had occasional TIAs, less frequent than before, whereas 1 patient had frequent TIAs and underwent revision of the revascularization. Angiographic studies were available in 11 patients, and showed improved flow in the hemispheres in 10 patients. Follow-up MR imaging performed at 6 months did not reveal a new infarct in any patient.

Conclusions

Repeat revascularization procedures are effective for patients who are clinically symptomatic and have inadequate collateral vessels following indirect procedures. Although direct procedures are preferred, the choice of procedure depends on the operative findings and the status of donor and recipient vessels.

Childhood moyamoya disease and moyamoya syndrome: a pictorial review

Moyamoya disease is an uncommon chronic cerebrovasculopathy, characterized by progressive stenosis of the terminal portion of the internal carotid artery and its main branches, in association with the development of compensatory collateral vessels at the base of the brain. The etiology is unknown, and was originally considered exclusive to East Asia, with particular prevalence in Japan. Moyamoya disease is increasingly diagnosed throughout the world, and represents an important cause of childhood stroke in Western countries. In some cases, similar angiographic features are evident in children with other medical conditions, such as sickle cell disease and Down syndrome. In these instances, the term "moyamoya syndrome" is used. Diagnosing the vasculopathy, excluding possible associated conditions, and planning treatment and follow-up imaging comprise important aspects of clinical management. We review the key imaging features of childhood moyamoya disease and syndrome, present examples of its associations, and discuss new neuroradiologic methods that may be useful in management.

Indirect revascularization techniques for treating moyamoya disease

There have been many indirect revascularization techniques described by surgeons for the treatment of moyamoya disease. These surgical procedures are typically used more commonly in pediatric, than in adults', cases. Some of the techniques include: cervical sympathectomy, omental transplantation, multiple burr holes, encephalo-myo-synangiosis (EMS), encephalo-arterio-synangiosis (EAS), encephalo-duro-synangiosis (EDS), encephalo-myo-arterio-synangiosis (EMAS), encephalo-duro-arterio-synangiosis (EDAS), encephalo-duro-arterio-myo-synangiosis (EDAMS), encephalo-duro-galeo (periosteal)-synangiosis (EDGS), and combinations of all the above. This chapter will detail the technical aspects of many of these procedures and some of the reported clinical outcomes.

Superficial temporal artery-to-middle cerebral artery anastomosis with encephalo-duro-myo-synangiosis as a modified operative procedure for moyamoya disease

BACKGROUND

Various types of revascularization surgery have been performed for moyamoya disease. Although the efficacies of these operations are well recognized, the optimal operative procedure remains undecided. In this report, we describe our modified surgical revascularization procedure for moyamoya disease and retrospectively analyze the results of such surgeries on six sides in six adult patients.

METHODS

Our operative procedure, combining direct and indirect bypasses, is a superficial temporal artery to middle cerebral artery anastomosis with encephalo-duro-myo-synangiosis. The encephalo-duro-myo-synangiosis is an indirect bypass combining the encephalo-duro- and encephalo-myo-synangioses. This operative procedure has been used routinely in adult patients since 2002.

RESULTS

Perioperative complications were noted in one of the six operations. This complication was transient and no attributive lesions were detected on CT or MRI. Revascularization was seen in cerebral blood flow studies in all patients, and the clinical outcomes were excellent or good. Effective neovascularization through the grafts was observed in all patients in follow-up angiographies.

CONCLUSIONS

This operative procedure provides needed revascularization and prevents ischemic deficits. This modified procedure is useful for responding to subsequent additional ischemia in the area of the anterior cerebral artery and should be considered one of the optimal procedures for treating moyamoya disease.

Omental free-tissue transfer for coverage of complex upper extremity and hand defects--the forgotten flap

Free omental tissue transfer is a versatile reconstructive option for trunk, head and neck, and extremity reconstruction. Its utility is due to the length and caliber of the vascular pedicle and the malleability and surface area of the flap. We report our experience with omental free flap coverage of complex upper-extremity defects. A retrospective analysis of eight omental free-tissue transfers in seven patients with complex upper-extremity defects between 1999 and 2008 was performed. Indications, operative technique, and outcome were evaluated. Patient age ranged from 12 to 59 years with five male and two female patients. Indications included tissue defects due to crush-degloving injuries, pitbull mauling, or necrotizing soft tissue infection. All patients had prior operations including: revascularization, debridement, tendon repair, skin grafts, and/or fixation of associated fractures. One patient sustained severe bilateral crush-degloving injuries requiring free omental hemiflap coverage of both hands. The mean defect size was 291 cm(2) with all patients achieving complete wound coverage. No flap loss or major complications were noted. Laparoscopic-assisted omental free flap harvest was performed in conjunction with the general surgery team in three cases. Mean follow-up was 2 years. The omental free flap is a valuable, often overlooked reconstructive option. The long vascular pedicle and large amount of pliable, well-vascularized tissue allow the flap to be aggressively contoured to meet the needs of complex three-dimensional defects. In addition, laparoscopic-assisted harvest may aid with flap dissection and may result in reduced donor-site morbidity.

Understanding and treating moyamoya disease in children

Moyamoya disease, a known cause of pediatric stroke, is an unremitting cerebrovascular occlusive disorder of unknown etiology that can lead to devastating, permanent neurological disability if left untreated. It is characterized by progressive stenosis of the intracranial internal carotid arteries and their distal branches and the nearly simultaneous appearance of basal arterial collateral vessels that vascularize hypoperfused brain distal to the occluded vessels. Moyamoya disease may be idiopathic or may occur in association with other syndromes. Most children with moyamoya disease present with recurrent transient ischemic attacks or strokes. Although there is no definitive medical treatment, numerous direct and indirect revascularization procedures have been used to improve the compromised cerebral circulation, with outcomes varying according to procedure type. Such techniques improve the long-term outcome of patients with both idiopathic and syndrome-associated moyamoya disease. This review provides a comprehensive discussion of moyamoya disease in children, with an emphasis on the most effective surgical treatment options.

The omentum: anatomical, metabolic, and surgical aspects

INTRODUCTION

The omentum is acknowledged to have diverse functions in the pathophysiology of intra-abdominal disease. Its angiogenic properties act as a natural defense mechanism in peritonitis and intra-abdominal sepsis. With advancing technology the omentum is revealing itself as a new player in the field of molecular surgery with special reference to cancer, obesity and tissue reconstruction.

MATERIALS AND METHODS

This article reviews the existing and potential surgical applications of the omentum.

Surgical management of moyamoya disease

Moyamoya disease (MMD) is a progressive, occlusive disease of the distal internal carotid arteries associated with secondary stenosis of the circle of Willis. Symptoms include ischemic infarcts in children and hemorrhages in adults. Bypass of the stenotic vessel(s) is the primary surgical treatment modality for MMD. Superficial temporal artery-to-middle cerebral artery bypass is the most common direct bypass method. Indirect techniques rely on the approximation of vascularized tissue to the cerebral cortex to promote neoangiogenesis. This tissue may be in the form of muscle, pericranium, dura, or even omentum. This review highlights the surgical options available for the treatment of MMD.

Moyamoya disease: current concepts and future perspectives

Moyamoya disease is an uncommon cerebrovascular disease that is characterised by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. The disease is associated with the development of dilated, fragile collateral vessels at the base of the brain, which are termed moyamoya vessels. The incidence of moyamoya disease is high in east Asia, and familial forms account for about 15% of patients with this disease. Moyamoya disease has several unique clinical features, which include two peaks of age distribution at 5 years and at about 40 years. Most paediatric patients have ischaemic attacks, whereas adult patients can have ischaemic attacks, intracranial bleeding, or both. Extracranial-intracranial arterial bypass, including anastomosis of the superficial temporal artery to the middle cerebral artery and indirect bypass, can help prevent further ischaemic attacks, although the beneficial effect on haemorrhagic stroke is still not clear. In this Review, we summarise the epidemiology, aetiology, clinical features, diagnosis, surgical treatment, and outcomes of moyamoya disease. Recent updates and future perspectives for moyamoya disease will also be discussed.

Moyamoya disease in pediatric patients: outcomes of neurosurgical interventions

✓Neurosurgical interventions for moyamoya disease (MMD) in pediatric patients include direct, indirect, and combined revascularization procedures. Each technique has shown efficacy in the treatment of pediatric MMD; however, no single study has demonstrated the superiority of one technique over another. In this review, the authors explore the various studies focused on the use of these techniques for MMD in the pediatric population. They summarize the results of each study to clearly depict the clinical outcomes achieved at each institution that had utilized direct, indirect, or combined techniques. In certain studies, multiple techniques were used, and the clinical or radiological outcomes were compared accordingly.

Direct techniques have been shown to aid a reduction in perioperative strokes and provide immediate revascularization to ischemic areas; however, these procedures are technically challenging, and not all pediatric patients are appropriate candidates. Indirect techniques have also shown efficacy in the pediatric population but may require a longer period for revascularization to occur and perfusion deficits to be reversed. The authors concluded that the clinical efficacy of one technique over another is still unclear, as most studies have had small populations and the same outcome measures have not been applied. Authors who compared direct and indirect techniques noted approximately equal clinical outcomes with differences in radiological findings. Additional, larger studies are needed to determine the advantages and disadvantages of the different techniques for the pediatric age group.

Subcutaneous tissue graft including a scalp artery and a relevant vein for the treatment of cerebral ischemia in childhood moyamoya disease

BACKGROUND

Simple indirect anastomosis was introduced for the treatment of moyamoya disease with cerebral ischemia in the territory of anterior cerebral arteries (ACAs) or middle cerebral arteries (MCAs), and its clinical usefulness was discussed.

METHODS

The study included 19 patients with childhood moyamoya disease who were operated on with subcutaneous tissue graft including a scalp artery and a relevant vein (group 1). They all had repetitive transient ischemic attacks (TIAs) in the territory of ACAs or MCAs. To compare age, sex, and the time required for the operation, 34 patients with childhood moyamoya disease with direct anastomosis were also included in the (group 2).

RESULTS

No TIAs were observed in 19 of 21 operative sides during the follow-up period in group 1. The remaining 2 sides continued to have TIAs postsurgically, but with a marked decrease in frequency. There were no significant differences in age and sex between group 1 and group 2. Required time for surgical procedure in group 1 ranged from 103 to 270 minutes (mean +/- SD, 167.4 +/- 38.8 minutes), and in group 2 from 140 to 320 minutes (215.0 +/- 36.2 minutes). The former was significantly shorter than the latter (unpaired t test, t = 4.8773, P = .000007).

CONCLUSIONS

Subcutaneous tissue graft including a scalp artery and a relevant vein is recommended for the treatment of moyamoya disease presenting ischemia in the territory of the ACAs or MCAs.

Combined direct anastomosis and encephaloduroarteriogaleosynangiosis using inverted superficial temporal artery–galeal flap and superficial temporal artery–galeal pedicle in adult moyamoya disease

BACKGROUND

We evaluated the efficacy of combined STA-MCA anastomosis and EDAGS using inverted STAGF and STAGP for the treatment of adult MMD.

METHODS

This study included 8 patients with nonhemorrhagic MMD. There were 6 women and 2 men who were between 23 and 62 years old (mean = 37.8 years) in the sample. The combined surgery was performed on 12 sides in the 8 patients. The surgical results were assessed for clinical outcome, angiographic revascularization, and hemodynamic change on HMPAO brain SPECT. The follow-up period ranged from 6 to 62 months (mean = 27 months).

RESULTS

Clinical symptoms and signs were improved or stabilized, and the extent of revascularization evident on external carotid angiograms was excellent in all 8 patients. The CBF on HMPAO SPECT also improved in all 12 sides that were operated on with the combined surgery, except for the preexisting infarcted area, on the basal as well as Diamox stimulation studies. One patient had a transient speech disturbance after surgery, and another patient had delayed wound healing.

CONCLUSIONS

The combined STA-MCA anastomosis and EDAGS using inverted STAGF/P seems to be one of the most effective surgical modalities for the treatment of nonhemorrhagic MMD in adults.

Ischemic Stroke in a Postpartum Patient: Understanding the Epidemiology, Pathogenesis, and Outcome of Moyamoya Disease

BACKGROUND

Moyamoya disease (MMD), or spontaneous occlusion of blood vessels in the circle of Willis, is a noninflammatory, nonatheromatous vasculopathy that often presents with ischemia or hemorrhage and has a tendency to affect young women. We discuss a case of a woman 7 days postpartum with new onset strokes, suspected initially to have benign angiopathy of the central nervous system (BACNS)/postpartum angiopathy versus primary CNS vasculitis. Cerebral angiography was suspicious for MMD and the patient underwent surgical revascularization.

OBJECTIVES

To review the epidemiology, presentation, diagnosis, differential diagnosis, treatment, prognosis, and postpartum maternal outcomes of MMD.

METHODS

The authors reviewed the English-language literature published between 1996 and 2004 using Medline databases. Additional articles were obtained from references described in literature obtained by the primary search.

RESULTS

MMD is characterized by severe bilateral stenosis of the distal internal carotid arteries and their first branches, with prominent collateralization. Autoantibodies relating to endothelial cell dysfunction have been studied as possible pathogenetic mechanisms. The gold standard for diagnosing MMD is digital subtraction contrast angiography (DSA). MMD-related findings on imaging studies may, at times, be mistaken for those of vasculitis. A surgical approach may need to be considered. Despite treatment, the overall prognosis of MMD is worse in adults compared with children.

CONCLUSION

Awareness of the specific features of MMD is crucial for clinical decision-making to avoid unnecessary exposure to aggressive immunosuppressive therapy. It is important for rheumatologists to consider MMD in the differential diagnosis of suspected CNS vasculitis.

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.

Assessment of cerebral hemodynamics in childhood moyamoya disease using a quantitative and a semiquantitative IMP-SPECT study

BACKGROUND

We evaluated the cerebral hemodynamics in childhood moyamoya disease patients before and after surgery to assess both surgical indication and the effect of revascularization using single photon emission computed tomography (SPECT) study with N-isopropyl-p-123I-iodoamphetamine (IMP). We compared results of quantitative and semi-quantitative SPECT studies to determine parameters by the semi-quantitative method to define severe hemodynamic ischemia.

METHODS

There were 14 pediatric patients with moyamoya disease who suffered transient ischemic attacks (TIAs) in the anterior circulation. Before and after surgical revascularization by STA-MCA bypass and encephalomyosynangiosis (EMS), quantitative IMP-SPECT studies using the autoradiographic method (IMP-ARG method) were performed. Resting regional cerebral blood flow (rCBF) and regional vascular reserve (rVR) were measured in bilateral cortical territories (ROI) and cerebellum. Semi-quantitative parameters were calculated from the ratio of ROI counts to the dominant cerebellar counts (ROI/Ce ratio) at resting and acetazolamide-activated conditions.

RESULTS

Before surgery, the mean resting rCBF and rVR in bilateral ACA and MCA territories were less than 40 ml/100 g/min and less than 10%, respectively, indicating severe hemodynamic ischemia. Except for the ACA territories, both the mean resting rCBF and mean rVR values in the entire cortex increased significantly after surgery (p < 0.05). By semi-quantitative studies, before surgery, the mean resting and acetazolamide-activated ROI/Ce ratios in bilateral ACA and MCA territories were less than 0.90 and 0.80, respectively. The mean resting and acetazolamide-activated ROI/Ce ratios increased significantly in the MCA territory after surgery. Severe hemodynamic ischemia, which categorized by the quantitative thresholds (resting rCBF < 40 ml/100 g/min and rVR < 10%) was diagnosed by the semi-quantitative thresholds (resting ROI/ Ce ratio < 0.90 and acetazolamide-activated ROI/Ce ratio < 0.85), the sensitivity and specificity of which were 87.5% and 90.9%, respectively.

CONCLUSIONS

The cerebral hemodynamics in childhood moyamoya disease was improved entirely after surgery. Severe hemodynamic cerebral ischemia was diagnosed by not only quantitative but also semi-quantitative IMP-SPECT studies.

Effects of indirect bypass surgery for occlusive cerebrovascular diseases in adults

The efficacy of indirect bypass surgery on hemodynamics in elderly adults with occlusive/stenotic cerebrovascular disease was retrospectively investigated in five elderly patients. Three cases were diagnosed as quasi-moyamoya disease. One patient was diagnosed with moyamoya disease. Of these four patients, three patients showed marked transdural leptomeningeal anastomosis. All patients showed certain areas of hypoperfusion with impairment of the perfusion reserve in the affected areas. All patients underwent encephalo-duro-arterio-synangiosis (EDAS) unilaterally and were followed up for 1-5 years. Three patients showed improvement of hemodynamic status, all of whom showed spontaneously developed leptomeningeal anastomosis in the preoperative angiographies. In two of these three patients, well-developed collateral formation from the graft was observed angiographically. We speculated that in addition to impaired cerebral perfusion reserve, spontaneously developed leptomeningeal anastomosis might be the key factor for the efficacy of indirect bypass in elderly patients with occlusive/stenotic cerebrovascular disease.