Histopathological correlation of brain tumor recurrence vs. radiation effect post-radiosurgery as detected by MRI contrast clearance analysis: a validation study.

PURPOSE: The differentiation between adverse radiation effects (ARE) and tumor recurrence or progression (TRP) is a major decision-making point in the follow-up of patients with brain tumors. The advent of immunotherapy, targeted therapy and radiosurgery has made this distinction difficult to achieve in several clinical situations. Contrast clearance analysis (CCA) is a useful technique that can inform clinical decisions but has so far only been histologically validated in the context of high-grade gliomas. METHODS: This is a series of 7 patients, treated between 2018 and 2023, for various brain pathologies including brain metastasis, atypical meningioma, and high-grade glioma. MRI with contrast clearance analysis was used to inform clinical decisions and patients underwent surgical resection as indicated. The histopathology findings were compared with the CCA findings in all cases. RESULTS: All seven patients had been treated with gamma knife radiosurgery and were followed up with periodic MR imaging. All patients underwent CCA when the necessity to distinguish tumor recurrence from radiation necrosis arose, and subsequently underwent surgery as indicated. Concordance of CCA findings with histological findings was found in all cases (100%). CONCLUSIONS: Based on prior studies on GBM and the surgical findings in our series, delayed contrast extravasation MRI findings correlate well with histopathology across a wide spectrum of brain tumor pathologies. CCA can provide a quick diagnosis and have a direct impact on patients' treatment and outcomes.

Does Reader Engagement with Neurosurgery Journal Websites Correlate with the Number of Citations Received by Articles?

BACKGROUND: Medicine has begun adapting to new information-sharing paradigms in the hyper-connected social media era. In this milieu, the role of journal websites in the dissemination of clinical and research information needs to be reevaluated. OBJECTIVE: We sought to explore whether reader engagement with neurosurgical journal websites, reflected by the number of article views and downloads, correlated with the eventual number of citations received by the articles. METHODS: The websites of all Medline indexed neurosurgical journals were screened to identify those that provided information regarding the number of abstract and full text views and downloads. Articles published in these journals between July 2010 and June 2011 were included in this analysis. Various article attributes were identified and the number of citations per article was obtained from Google Scholar. The impact factors of the selected journals for the year 2010 were obtained from the Journal Citation Reports. RESULTS: Twenty-two journals that had published 2527 articles were finally included in this analysis. The number of abstract views, full-text views, and downloads all correlated strongly with the journal impact factors in 2010 as well as the eventual citations per article. The number of article downloads independently predicted the citations per article on multivariate analysis. Neurology India had significantly higher article views and downloads but lower citations per article than the other journals. CONCLUSIONS: Readers were found to engage significantly with neurosurgical journal websites and therefore, open access to articles would lead to increased visibility of articles, resulting in higher citation rates.

A survey of surveys: an evaluation of the quality of published surveys in neurosurgery.

PURPOSE: Surveys generate valuable data in epidemiologic and qualitative clinical research. The quality of a survey depends on its design, the number of responses it receives, and the reporting of the results. In this study, we aimed to assess the quality of surveys in neurosurgery. METHODS: Neurosurgical surveys published between 2000 and 2020 (inclusive) were identified from PubMed. Various datapoints regarding the surveys were collated. The number of citations received by the papers was determined from Google Scholar. A 6-dimensional quality assessment tool was applied to the surveys. Parameters from this tool were combined with the number of responses received to create the survey quality score (SQS). RESULTS: A total of 618 surveys were included for analysis. The target sample size correlated with the number of responses received. The response rate correlated positively with the target sample size and the number of reminders sent and negatively with the number of questions in the survey. The median number of authors on neurosurgery survey papers was 6. The number of authors correlated with the SQS and the number of citations received by published survey papers. The median normalized SQS for neurosurgical surveys was 65%. The nSQS independently predicted the citations received per year by surveys. CONCLUSIONS: The modifiable factors that correlated with improvements in survey design were optimizing the number of questions, maximizing the target sample size, and incorporating reminders in the survey design. Increasing the number of contributing authors led to improvements in survey quality. The SQS was validated and correlated well with the citations received by surveys.

Short- and long-term outcomes of moyamoya patients post-revascularization.

OBJECTIVE: The post-bypass stroke risk factors and long-term outcomes of moyamoya patients are not well documented. Therefore, the authors studied 30-day stroke risks and patients' long-term physical, functional, and social well-being. METHODS: This was a single-institution combined moyamoya disease (MMD) database interrogation and questionnaire study. From 1991 to 2014, 1250 revascularization procedures (1118 direct bypasses, 132 indirect bypasses) were performed in 769 patients. Completed questionnaires were received from and available for analysis on 391 patients, and 6-month follow-up data were available for 96.4% (741/769) of the patients. RESULTS: The patients consisted of 548 females and 221 males, with a mean age of 32 years (range 1-69 years). Three hundred fifty-eight bypasses were performed in 205 pediatric patients (73% direct bypasses), and 892 revascularizations were performed in 564 adults (96% direct bypasses). Fifty-two patients (6.8%) developed major strokes with a worsening modified Rankin Scale (mRS) score within 30 days postoperatively. The 30-day major stroke risk was 5.3% (41/769) and 2.6% (12/467) after the first and second bypasses, respectively. Logistic regression analysis revealed that older age, modified MRI (mMRI) score, and hemodynamic reserve (HDR) score are clearly associated with higher postoperative stroke risks. Over a mean follow-up of 7.3 years (range 0.5-26 years), the long-term stroke risk among 741 patients was 0.6% per patient-year; 75% of these patients had excellent outcomes (mRS score 0-1). The long-term outcome questionnaire study showed that 84% (234/277) of patients reported resolution or improvement in their preoperative headache, 83% (325/391) remained employed or in school, and 87% (303/348) were self-caring. CONCLUSIONS: In this large, single-center surgical series, most of the adult and pediatric patients had direct revascularization, with a 4.2% per-bypass-procedure (6.8% per patient) 30-day major stroke risk and a 0.6% per-patient-year long-term stroke risk. The authors identified various risk factors that are highly correlated with postoperative morbidity (age, mMRI score, and HDR score) and are involved in ongoing work to develop the predictive modeling for future patient selection and treatment.

An Analysis of Eosinophil- and Basophil-Based Indices in Patients with Glioblastoma and their Correlation with Survival.

BACKGROUND: Glioblastoma (GBM) is the most frequently diagnosed malignant brain tumor in adults. GBM is usually lethal within 24 months of diagnosis, despite aggressive multimodality treatment. Although it has been established that cancer-related inflammation is associated with worse outcomes, the role of eosinophils, basophils, atopy, and allergy in glioma biology is only gradually being delineated. In this study, we aimed to examine if eosinophil-based and basophil-based indices were altered in patients with GBM compared with healthy controls. We also aimed to study if there was any correlation between these indices and patient-related and tumor-related factors and survival. METHODS: This study was a retrospective analysis of prospectively maintained databases. Data pertaining to patient-related and tumor-related factors, hemograms, and survival data were obtained from the electronic medical records of selected patients. Correlations between eosinophil-based and basophil-based indices and these factors were studied, as was the association with overall survival. RESULTS: All the indices were altered in patients with GBM compared with normal healthy controls. The absolute eosinophil count was higher and the neutrophils/eosinophils ratio was lower in the better prognosis groups: those with better performance status; those without features of increased intracranial pressure or altered sensorium at presentation; those with ATRX-retained tumors that did not overexpress p53; and in the long-term survivors. The total lymphocyte count/basophils ratio and the absolute eosinophil count both independently predicted survival in a multivariate analysis. CONCLUSIONS: The absolute eosinophil count was consistently higher in the better prognosis groups and is likely to be incorporated into prognostic models for GBM.

Chaotic lipoma with proximal syrinx -a (not so) rare variant - review of the literature, possible embryology and management.

Chaotic lipomas are an extremely rare variant of spinal lipomas. This entity was first defined in 2009 by Pang and colleagues. Not much has been written about this variant. Its characteristic is the haphazard distribution of DREZ (Dorsal root entry zone), nerve roots and placode-lipoma interface. Thus complete/near-total excision of this lesion is quite difficult. We describe a case of chaotic spinal lipoma and elucidate the challenges faced in the management of this entity and review the literature. We performed a thorough systematic review with the keyword 'chaotic', 'Lipomyelomeningocele', 'Complex Lipomyelomeningocele', 'LMMC', 'Lumbar lipoma', 'spinal lipoma' in the google scholar and PUBMED data system for indexed literature on the above topic with no particular time frame. The studies quoted range earliest from 1970 till currently. Additional potential relevant articles were further retrieved through a manual search of references from original reports. Out of 42 studies, a total of 21 publications were selected which could have encountered a chaotic variant, but due to the term introduced only recently in 2009, may have been described differently. Studies encompassing true lipomeningomyelocele were excluded from our review. What we found out? Chaotic lipoma may not be a new entity. The scarce description in literature may be in part due to non-introduction and unclear description of this term earlier. The management of this variant is particularly challenging with basic principles remaining the same. Meticulous near-total excision and placode-lipoma construct are the major obstacles.

The Author-Level Metrics Study: An Analysis of the Traditional and Alternative Metrics of Scholarly Impact for Neurosurgical Authors.

Background and objective There is a paucity of information regarding the concordance of traditional metrics across publicly searchable databases and about the correlation between alternative and traditional metrics for neurosurgical authors. In this study, we aimed to assess the congruence between traditional metrics reported across Google Scholar (GS), Scopus (Sc), and ResearchGate (RG). We also aimed to establish the mathematical correlation between traditional metrics and alternative metrics provided by ResearchGate. Methods Author names listed on papers published in the Journal of Neurosurgery (JNS) in 2019 were collated. Traditional metrics [number of publications (NP), number of citations (NC), and author H-indices (AHi)] and alternative metrics (RG score, Research Interest score, etc. from RG and the GS i10-index) were also collected from publicly searchable author profiles. The concordance between the traditional metrics across the three databases was assessed using the intraclass correlation coefficient and Bland-Altman (BA) plots. The mathematical relation between the traditional and alternative metrics was analyzed. Results The AHi showed excellent agreement across the three databases studied. The level of agreement for NP and NC was good at lower median counts. At higher median counts, we found an increase in disagreement, especially for NP. The RG score, number of followers on RG, and Research Interest score independently predicted NC and AHi with a reasonable degree of accuracy. Conclusions A composite author-level matrix with AHi, RG score, Research Interest score, and the number of RG followers could be used to generate an "Impact Matrix" to describe the scholarly and real-world impact of a clinician's work.

Simplifying the Surgical Strategy for Excising Medial Sphenoid Wing Meningiomas: A Stepwise Approach.

Background: Medial sphenoid wing meningiomas constitute 15%-20% of all intracranial meningiomas. These lesions have a propensity to encase the vessels of the circle of Willis and the surrounding cranial nerves. Thus, radical excision is a difficult proposition. Objectives: In this paper, we analyzed our series of sphenoid wing meningiomas. We describe our surgical strategy, which was based on zone-wise dissection of the tumor. We describe the complications and outcomes of surgery. Materials and Methods: This case series is a retrospective analysis of a single surgeon series of medial sphenoid wing meningiomas operated over a 13-year period. Clinical, radiographic, and outcome variables were studied. The surgical videos were analyzed in detail. The meningioma and its extensions were divided into several zones and a zone-wise strategy for tumor excision was evolved. Results: Twenty-four patients with medial sphenoid wing meningiomas were operated. In 14 patients, Simpson grade 3 excision could be achieved; 5 patients had Simpson grade 4 and 1 patient, grade 5 excision. Four (of 24 patients, 16.7%) had vessel injuries. Conclusions: Medial sphenoid wing meningiomas are difficult lesions to excise radically. Close follow-up of residual lesions (especially if attached to the basal dura) is warranted. Additional modalities of treatment like radiosurgery may be required in case of any progression and for higher-grade lesions.

Heartbroken Child: A Rare Case Report of Neurogenic Pulmonary Edema and Takotsubo Cardiomyopathy following Recurrent Medulloblastoma Excision with Possible Aetio-Patho-Bio-Physiological Mechanisms.

INTRODUCTION: Takotsubo (Japanese fishing pot for trapping octopus) cardiomyopathy is a rare phenomenon of acute coronary syndrome presenting usually with the presence of transient apical ballooning of the left ventricle in the absence of obstructive coronary artery disease. It is mainly seen in women of older age secondary to emotional, physical, or psychological stress. In age less than 18 years, it is mainly seen in adolescents suffering from psychiatric disorders and substance abuse. In children, it is rarely described. CASE PRESENTATION: We present here a peculiar case of a 12-year-old child with neurogenic pulmonary oedema and takotsubo cardiomyopathy syndrome after surgery for recurrent medulloblastoma. Also, management challenges are discussed. DISCUSSION/CONCLUSION: Takotsubo cardiomyopathy is not just a classical or inverted type but indeed a spectrum. It can be seen in any case, be it a child or adult secondary to handling or injury to the ponto-medullary junction, rostral pons, or dorsolateral medulla. The density and distribution of beta-adrenergic receptors may be different in children and adults which needs further research. Prognosis is usually excellent across all ages.

Biomarkers of Systemic Inflammation in Patients with Glioblastoma: An Analysis of Correlation with Tumour-Related Factors and Survival.

BACKGROUND: Biomarkers of systemic inflammation (BMSIs), including haemogram cell counts (CC, e.g., absolute neutrophil count) and cell count-ratios (CCR, e.g., the neutrophil-lymphocyte ratio, etc.), have been found to have prognostic significance in many solid-organ cancers. AIMS: In this three-part study, we first examined if the CCs and CCRs were altered in patients with glioblastoma (GBM) when compared with healthy controls. Second, we evaluated for any correlation between the BMSIs and patient- and tumour-related factors. Third, we evaluated the influence of the CCs and CCRs on survival. METHODS: This was a retrospective analysis of patients who underwent surgery/biopsy for a newly diagnosed brain tumour that was subsequently confirmed to be GBM (Cases). Controls were healthy individuals who underwent pre-employment screening blood tests. STATISTICAL METHODS: Parametric tests were used to compare normally distributed continuous variables, whereas non-normally distributed variables were compared using non-parametric tests. Thresholds for the BMSIs were determined using X-tile analysis. Cox regression using the proportional hazards model was used for survival analyses around the determined thresholds. RESULTS: All CCs and CCRs were altered in Cases compared with Controls. Presentation with raised intracranial pressure, altered sensorium, poor performance status, loss of ATRX, and lack of p53 overexpression was associated with an inflammatory phenotype of changes in the BMSIs. The inflammatory phenotype of changes was associated with poor survival. CONCLUSIONS: A significant inflammatory response was found in patients with GBM and correlated with clinical features, the molecular profile of the tumour and poor survival.

A Questionnaire-based Survey of Clinical Neuro-oncological Practice in India.

BACKGROUND: Neuro-oncology is a relatively young subspecialty of neurosurgery. 2018 was the 10th year since the founding of the Indian Society of Neuro-oncology. OBJECTIVE: To assess patterns in neuro-oncology practice in India. METHODS: This was an online survey covering various domains of neuro-oncology such as demographics and practice setting, protocols for the medical management of patients with brain tumors, protocols for surgery and the perioperative period (including antibiotic prophylaxis, dural closure techniques, etc.), technological adjuncts used for brain/spine tumors (including intraoperative neurologic monitoring-IONM), and management protocols for certain specific clinical scenarios. RESULTS: The response rate was 13%. Although 37% of the respondents' institutions could be considered as having reasonable surgical volumes (>1 procedure/day), only about half of these had high volumes of malignant brain tumor surgery. A wide variation was seen in medical management, perioperative protocols, use of adjuncts and intraoperative technologies, and paradigms for specific clinical scenarios. CONCLUSIONS: There is a need to standardize the protocols in neuro-oncology. This could be achieved by strengthening the formal training process in surgical neuro-oncology.

An Estimation of the Retraction Gap Across Neurosurgery-A Crevice or a Chasm?

BACKGROUND: The incidence of retractions has been increasing steadily, in direct proportion to the volume of scientific literature. Retraction of published articles depends on the visibility of journals and on postpublication scrutiny of published articles by peers. The possibility thus exists that not all compromised ("retractable") articles are detected and retracted from the less-visible journals. The proportion of "retractable" articles and its converse, the proportion of published articles in each journal that are likely to be "true" (PTP), have not been estimated hitherto. METHODS: Three journal sets were created: pure neurosurgery journals (NS-P), the neurosurgery component of multidisciplinary journals (NS-MD), and high-impact clinical journals (HICJs). We described a new metric (the retraction gap [RGap]), defined as the proportion of retractable articles in journals that have not been retracted. We computed the expected number of retractable articles, RGap, and PTP for each journal, and compared these metrics across groups. RESULTS: Fifty-three NS-P journals, 10 NS-MD journals, and 63 HICJs were included in the analysis. The estimated number of retractable articles was 31 times the actual number of retractions in NS-P journals, 6 times higher in the NS-MD journals, and 26 times higher for the HICJs. The RGap was 96.7% for the NS-P group, 83.5% for the NS-MD group, and 96.2% for the HICJs. The PTP was 99.3% in the NS-P group, 99.2% in the NS-MD group, and 98.6% in the HICJs. CONCLUSIONS: Neurosurgery as a discipline had a higher RGap but also a higher PTP than the other 2 groups.

Analysis of Factors Associated with Long-Term Survival in Patients with Glioblastoma.

BACKGROUND: Some patients with glioblastoma multiforme (GBM) survive 3-5 years (or longer) after diagnosis. The goal of this study was to identify differences between the long-term survivors (LTS) and those who had a shorter overall survival (non-LTS groups). METHODS: This study was a retrospective analysis of prospectively maintained surgical databases. All patients who underwent safe maximal resection for GBM were included. Demographic, clinical, radiologic, and pathologic data were obtained from electronic medical records. Values of the biomarkers of systemic inflammation were computed from the preoperative hemogram reports. Patients with an overall survival (OS) ≥36 months were defined as the LTS group and were compared with the non-LTS groups (OS<36 months). RESULTS: Patients in the LTS group were younger, had a better baseline performance status, and were more likely to have undergone near- or gross-total resection. LTS was associated with lower Ki67 labeling, MGMT methylation, IDH mutation, and lack of p53 overexpression. Several novel findings were generated by this study. A longer pretreatment duration of symptoms was associated with a longer OS. Higher pretreatment levels of the absolute neutrophil count, neutrophil-lymphocyte ratio, monocyte-lymphocyte ratio, derived neutrophil-lymphocyte ratio and systemic index of inflammation, and lower levels of the absolute eosinophil count and eosinophil-lymphocyte ratio all correlated with a shorter OS. CONCLUSIONS: Several differences were identified between the LTS and non-LTS groups. These differences will likely be incorporated into future prognostic models. They may also aid in differentiation between recurrent disease and treatment-related changes.

An analysis of retractions in neurosurgery and allied clinical and basic science specialties.

BACKGROUND: As the volume of scientific publications increases, the rate of retraction of published papers is also likely to increase. In the present study, we report the characteristics of retracted papers from clinical neurosurgery and allied clinical and basic science specialties. METHODS: Retracted papers were identified using two separate search strategies on PubMed. Attributes of the retracted papers were collected from PubMed and the Retraction Watch database. The reasons for retraction were analyzed. The factors that correlated with time to retraction were identified. Detailed citation analysis for the retracted papers was performed. The retraction rates for neurosurgery journals were computed. RESULTS: A total of 191 retractions were identified; 55% pertained to clinical neurosurgery. The most common reasons for retraction were plagiarism, duplication, and compromised peer review. The countries associated with the highest number of retractions were China, USA, and Japan. The full text of the retraction notice was not available for 11% of the papers. A median of 50% of all citations received by the papers occurred after retraction. The factors that correlated with a longer time to retraction included basic science category, the number of collaborating departments, and the H-index of the journal. The overall rate of retractions in neurosurgery journals was 0.037%. CONCLUSIONS: The retraction notice needs to be freely available on all search engines. Plagiarism checks and reference checks prior to publication of papers (to ensure no retracted papers have been cited) must be mandatory. Mandatory data deposition would help overcome issues with data and results.

Journal Retraction Rates and Citation Metrics: An Ouroboric Association?

Introduction Retraction of published papers has a far-reaching impact on the scientific world, especially if the retracted papers were published in high-impact journals. Although it has been noted that the retraction rates of journals correlated with their citation metrics, no conclusive data were available for most clinical specialties. In this study, we determined the retraction rate for anesthesia and two comparison groups (neurosurgery and high impact clinical journals). We then studied the correlation of the retraction rate with citation metrics. Methods We generated a list of all anesthesia journals that were indexed in the National Library of Medicine database. We obtained the number of papers published in each journal as well as the number of papers retracted from each. We also collated the Impact Factor® and H-index of each journal. The same methodology was followed for neurosurgery and high impact clinical journals. We then studied the correlations between the retraction rate and citation metrics of each journal. Results The retraction index was 2.59 for anesthesiology, 0.66 for neurosurgery and 0.75 for the high-impact clinical journals group. The retraction rate did not correlate with the citation metrics. However, the number of papers published in each journal and the absolute number of retractions showed a positive correlation with the citation metrics. The H-index showed stronger correlations with these parameters than the Impact factor. Conclusions The number of retractions increased in proportion to both the number of papers published in a journal and the citation metrics of that journal.

Validation and Application for the Berlin Grading System of Moyamoya Disease in Adult Patients.

BACKGROUND: Traditional moyamoya disease (MMD) classification relies on morphological digital subtraction angiography (DSA) assessment, which do not reflect hemodynamic status, clinical symptoms, or surgical treatment outcome. OBJECTIVE: To (1) validate the new Berlin MMD preoperative symptomatology grading system and (2) determine the clinical application of the grading system in predicting radiological and clinical outcomes after surgical revascularization. METHODS: Ninety-six MMD patients (192 hemispheres) with all 3 investigations (DSA, magnetic resonance imaging [MRI], Xenon-CT) performed preoperatively at our institution (2007-2013) were included. Two clinicians independently graded the imaging findings according to the proposed criteria. Patients' modified Rankin Score (mRS) scores (preoperative, postoperative, last follow-up), postoperative infarct (radiological, clinical) were collected and statistical correlations performed. RESULTS: One hundred fifty-seven direct superficial temporal artery-middle cerebral artery bypasses were performed on 96 patients (66 female, mean age 41 yr, mean follow-up 4.3 yr). DSA, MRI, and cerebrovascular reserve capacity were independent factors associated hemispheric symptomatology (when analyzed individually or in the combined grading system). Mild (grade I), moderate (grade II), severe (grade III) were graded in 45, 71, and 76 hemispheres respectively; of which, clinical symptoms were found in 33% of grade I, 92% of grade II, 100% of grade III hemispheres (P < .0001). Two percent of grade I, 11% of grade II, 20% of grade III hemispheres showed postoperative radiological diffusion weighted image-positive ischemic changes or hemorrhage on MRI (P = .018). Clinical postoperative stroke was observed in 1.4% of grade II, 6.6% of grade III hemispheres (P = .077). The grading system also correlated well to dichotomized mRS postoperative outcome. CONCLUSION: The Berlin MMD grading system is able to stratify preoperative hemispheric symptomatology. Furthermore, it correlated with postoperative new ischemic changes on MRI, and showed a strong trend in predicting clinical postoperative stroke.

Early Diffusion Magnetic Resonance Imaging Changes in Normal-Appearing Brain in Pediatric Moyamoya Disease.

BACKGROUND: Moyamoya disease often leads to ischemic strokes visible on diffusion-weighted imaging (DWI) and T2-weighted magnetic resonance imaging (MRI) with subsequent cognitive impairment. In adults with moyamoya, apparent diffusion coefficient (ADC) is correlated with regions of steal phenomenon and executive dysfunction prior to white matter changes. OBJECTIVE: To investigate quantitative global diffusion changes in pediatric moyamoya patients prior to explicit structural ischemic damage. METHODS: We retrospectively reviewed children (<20 yr old) with moyamoya disease and syndrome who underwent bypass surgery at our institution. We identified 29 children with normal structural preoperative MRI and without findings of cortical infarction or chronic white matter ischemic changes. DWI datasets were used to calculate ADC maps for each subject as well as for 60 age-matched healthy controls. Using an atlas-based approach, the cerebral white matter, cerebral cortex, thalamus, caudate, putamen, pallidum, hippocampus, amygdala, nucleus accumbens, and brainstem were segmented in each DWI dataset and used to calculate regional volumes and ADC values. RESULTS: Multivariate analysis of covariance using the regional ADC and volume values as dependent variables and age and gender as covariates revealed a significant difference between the groups (P < .001). Post hoc analysis demonstrated significantly elevated ADC values for children with moyamoya in the cerebral cortex, white matter, caudate, putamen, and nucleus accumbens. No significant volume differences were found. CONCLUSION: Prior to having bypass surgery, and in the absence of imaging evidence of ischemic stroke, children with moyamoya exhibit cerebral diffusion changes. These findings could reflect microstructural changes stemming from exhaustion of cerebrovascular reserve.

Contralateral acute vascular occlusion following revascularization surgery for moyamoya disease.

OBJECTIVE: Revascularization surgery is a safe and effective surgical treatment for symptomatic moyamoya disease (MMD) and has been shown to reduce the frequency of future ischemic events and improve quality of life in affected patients. The authors sought to investigate the occurrence of acute perioperative occlusion of the contralateral internal carotid artery (ICA) with contralateral stroke following revascularization surgery, a rare complication that has not been previously reported. METHODS: This study is a retrospective review of a prospective database of a single surgeon's series of revascularization operations in patients with MMD. From 1991 to 2016, 1446 bypasses were performed in 905 patients, 89.6% of which involved direct anastomosis of the superficial temporal artery (STA) to a distal branch of the middle cerebral artery (MCA). Demographic, surgical, and radiographic data were collected prospectively in all treated patients. RESULTS: Symptomatic contralateral hemispheric infarcts occurred during the postoperative period in 34 cases (2.4%). Digital subtraction angiography (DSA) was performed in each of these patients. In 8 cases (0.6%), DSA during the immediate postoperative period revealed associated new occlusion of the contralateral ICA. In each of these cases, revascularization surgery involved direct anastomosis of the STA to an M4 branch of the MCA. Preoperative DSA revealed moderate (n = 1) or severe (n = 3) stenosis or occlusion (n = 4) of the ipsilateral ICA and mild (n = 2), moderate (n = 4), or severe (n = 2) stenosis of the contralateral ICA. The baseline Suzuki stage was 4 (n = 7) or 5 (n = 1). The collateral supply originated exclusively from the intracranial circulation in 4/8 patients (50%), and from both the intracranial and extracranial circulation in the remaining 50% of patients. Seven (88%) of 8 patients improved symptomatically during the acute postoperative period with induced hypertension. The modified Rankin Scale (mRS) score at discharge was worse than baseline in 7/8 patients (88%), whereas 1 patient had only minor deficits that did not affect the mRS score. At the 3-year follow-up, 3/8 patients (38%) were at their baseline mRS score or better, 1 patient had significant disability compared with preoperatively, 2 patients had died, and 1 patient was lost to follow-up. Three-year follow-up is not yet available in 1 patient. CONCLUSIONS: Acute occlusion of the ICA on the contralateral side from an STA-MCA bypass is a rare, but potentially serious, complication of revascularization surgery for MMD. It highlights the importance of the hemodynamic interrelationships that exist between the two hemispheres, a concept that has been previously underappreciated. Induced hypertension during the acute period may provide adequate cerebral blood flow via developing collateral vessels, and good outcomes may be achieved with aggressive supportive management and expedited contralateral revascularization.