Astemizole, a Second-Generation Histamine H1-Receptor Antagonist, Did Not Attenuate the Aggregation Process of α-Synuclein In Vitro.

The antihistamine astemizole has shown disease-modifying effects in several preclinical disease models of Parkinson's disease (PD). Astemizole also interacts with an anomalous aggregation of Alzheimer's disease-related amyloid-ß (Aß) peptide and has inhibitory activity on the human prion protein PrPSc. We hypothesized that the proposed preclinical benefits of astemizole on PD can be associated with the attenuation of pathological α-synuclein (α-syn) aggregation. We tested the effects of astemizole on the fibrillation processes of amyloid peptides using thioflavin T aggregation monitoring, Congo red spectral analysis, cell viability study, and transmission electron microscopic imaging. We found that astemizole did not inhibit α-syn aggregation in vitro even at a high molar ratio but inhibited the assembly of Aß aggregates. Our results suggest that the inhibitory effect of astemizole on amyloid formation is target-protein selective, and the proposed beneficial effects of this compound observed in translational PD models might not be due to its ameliorating effects on α-syn aggregation.

Delayed fatal rupture of vertebral artery after treated with flow-diverter in fibromuscular dysplasia patient: A case report and review of the literature.

Fibromuscular dysplasia (FMD) is a noninflammatory arterial diseases that affects predominantly women. Multiple studies have demonstrated an increased prevalence of FMD in patients who experience carotid or vertebral artery dissection (VAD). This case report presents a 57-year-old female who presented with a headache and was diagnosed with partially thrombosed giant aneurysm of vertebral artery. This aneurysm was successfully treated with flow-diverter and coil, but new onset rupture of vertebral artery was detected two weeks later, leading to internal trapping. This case report underscores the need for awareness and understanding of treatment of dissection and aneurysm in patient who is suspected FMD.

Could A1 Aplasia or Hypoplasia Affect the Morphology and Rupture Risk of Anterior Communicating Artery Aneurysm?

OBJECTIVE: Anterior communicating artery (Acom) aneurysm is one of the most common intracranial aneurysms, constituting approximately 30-35% of all aneurysm formation in the brain. Anatomically, the H-complex (the anatomic morphology of both A1 to A2 segments) is thought to affects the nature of the Acom aneurysm due to its close relationship with the hemodynamics of the vessel. Therefore, we investigated the relative risk factors of aneurysmal rupture, especially focusing on H-complex morphology of the Acom. METHODS: From January 2016 to December 2020, a total of 209 patients who underwent surgery, including clipping and coiling for Acom aneurysm in our institution were reviewed. There were 102 cases of ruptured aneurysm and 107 cases of unruptured aneurysm. The baseline morphology of aneurysms was investigated and the relationship between the H-complex and the clinical characteristics of patients with Acom aneurysms was assessed. RESULTS: Of the 209 patients, 109 patients (52.1%) had symmetrical A1, 79 patients (37.8%) had unilateral hypoplastic A1, and 21 patients (10.0%) had aplastic A1. The hypoplastic A1 group and the aplastic A1 group were grouped together as unilateral dominancy of A1, and were compared with the symmetrical A1 group. There was no significant difference in demographic characteristics and radiological findings of Acom aneurysms between two groups. However, when dichotomizing the patients into ruptured cases and unruptured cases, unilateral dominance of the A1 segment was associated with aneurysmal rupture with statistical significance (p=0.011). CONCLUSION: These results suggest that the unilateral dominance of the A1 segment does not have a significant effect on the morphology of Acom aneurysms, but contributes to aneurysmal rupture. Thus, we can better understand the effects of hemodynamics on Acom aneurysm.

Pediatric Traumatic Brain Injury : The Epidemiology in Korea.

Traumatic brain injury (TBI) is one of the leading causes of death in the pediatric population in Korea. In addition, it can cause disability in children and adolescents, with physical and mental consequences. This causes a substantial burden on the health care system and occurs globally and not just in Korea. We searched and reviewed current data on the epidemiologic characteristics of pediatric TBI in Korea. Our review provides the recent epidemiological trend mainly focusing on incidence and mortality along with worldwide reported data. This review will be helpful to understand the global epidemiology of pediatric TBI and its differences between countries.

Premammillary artery infarction after microsurgical clipping of unruptured posterior communicating artery aneurysm: risk factors and surgical and anatomical considerations.

Posterior communicating artery (PCoA) aneurysm is common and sometimes requires microsurgery; however, as data on premammillary artery (PMA) infarction after clipping is scarce, we retrospectively reviewed cases of post-clipping PMA infarction to analyze incidence, independent risk factors of infarction, and anatomical considerations. Data from 569 consecutive patients who underwent microsurgical clipping for unruptured PCoA aneurysm between January 2008 and December 2020 were included. Patients were categorized into the normal or the PMA infarction group. Statistical analyses and comparisons between the two groups were used to determine the influence of various factors. The normal group included 515 patients while the PMA infarction group had 31. The mean length of hospital stay was significantly longer in the PMA infarction group (10.3 ± 9.1 days) than in the normal group (6.5 ± 6.4 days; p < 0.0001). The distribution of Glasgow Outcome Scale at discharge was significantly different between the two groups (p ≤ 0.0001) but was not so at 6 months after discharge (p = 0.0568). Multivariate logistic regression analysis identified aneurysm size (odds ratio [OR], 1.194; 95% confidence interval [CI], 1.08-1.32; p = 0.0005) and medial direction of aneurysm (OR, 4.615; 95% CI, 1.224-17.406; p = 0.0239) as independent risk factors of post-clipping PMA infarction. Surgeons must beware of PMA infarction after clipping of large aneurysms that are medial in direction. Intraoperative verification of the patency of the PCoA and the PMA from various angles using various intraoperative methods can reduce morbidity due to PMA infarction.

Endovascular management of cavernous sinus dural arteriovenous fistulas: Overall review and considerations.

Cavernous sinus dural arteriovenous fistulas (CSDAVFs) are arteriovenous shunts between small dural branches arising from the external and/or internal carotid arteries and the cavernous sinus (CS). And now a days, endovascular treatment is the treatment of choice in CSDAVF. We review the anatomy and classifications of CSDAVFs, discussing and detailing these considerations in the treatment of CSDAVFs, theoretically and in the light of recent literatures.

Aspiration-Retriever Technique for Stroke with Large Bore Intermediate Catheter : A Single Center Experience.

OBJECTIVE: Early successful reperfusion is associated with favorable outcomes in acute ischemic stroke (AIS). The purpose of this study was to achieve successful recanalization by a combined mechanical thrombectomy technique, the Aspiration-Retriever Technique for Stroke (ARTS), which is composed of a flexible large lumen distal access catheter and a retrievable stent as the first-line strategy of mechanical thrombectomy. METHODS: We retrospectively reviewed 62 patients with AIS who underwent mechanical thrombectomy from 2018 to 2019 at our institute by a senior neurointerventionalist. Among them, patients who were treated using the ARTS technique with the soft torqueable catheter optimized for intracranial access (SOFIA®; MicroVention-Terumo, Tustin, CA, USA) as the first-line treatment were included. Patients who had tandem occlusions or underlying intracranial artery stenosis were excluded. The angiographic and clinical outcomes were evaluated. The angiographic outcome was analyzed by the rate of successful recanalization, defined as a Thrombolysis in Cerebral Infarction score of 2b or 3 at the end of all procedures and the rate of successfully achieving the first pass effect (FPE), defined as complete recanalization with a single pass of the device. The clinical outcomes included the National Institutes of Health Stroke Scale (NIHSS) score, modified Rankin Scale (mRS), and mortality. RESULTS: A total of 27 patients (mean age, 59.3 years) fulfilled the inclusion criteria. The successful recanalization rate was 96% (n=26) while the FPE rate was 41% (n=11). The mean post-procedural NIHSS change was -3.0. Thirteen patients (48%) showed good clinical outcomes after thrombectomy with the ARTS technique (mRS at 90 days ≤2). Postoperative complications occurred in seven of 25 patients : hemorrhagic transformation in six patients (22%) and distal embolization in one patient (4%). Mortality was 15% (n=4). CONCLUSION: Although the clinical outcomes using the ARTS technique with a flexible large lumen distal access catheter performed as the frontline thrombectomy in patients with AIS were not significantly superior than those of other studies, this study showed a high rate of successful endovascular recanalization which was comparable to that of other studies. Therefore, ARTS using the SOFIA® catheter can be considered as the first choice of treatment for AIS due to large vessel occlusion.

Single- and hypofractionated stereotactic radiosurgery for large (> 2 cm) brain metastases: a systematic review.

PURPOSE: Since frameless stereotactic radiosurgery (SRS) techniques have been recently introduced, hypofractionated SRS (HF-SRS) for large brain metastases (BMs) is gradually increasing. To verify the efficacy and safety of HF-SRS for large BMs, we aimed to perform a systematic review and compared them with SF-SRS. METHODS: We systematically searched the studies regarding SF-SRS or HF-SRS for large (> 2 cm) BM from databases including PubMed, Embase, and the Cochrane Library on July 31, 2018. Biologically effective dose with the α/ß ratio of 10 (BED10), 1-year local control (LC), and radiation necrosis (RN) were compared between the two groups, with the studies being weighted by the sample size. RESULTS: The 15 studies with 1049 BMs that described 1-year LC and RN were included. HF-SRS tended to be performed in larger tumors; however, higher mean BED10 (50.1 Gy10 versus 40.4 Gy10, p < 0.0001) was delivered in the HF-SRS group, which led to significantly improved 1-year LC (81.6 versus 69.0%, p < 0.0001) and 1-year overall survival (55.1 versus 47.2%, p < 0.0001) in the HF-SRS group compared to the SF-SRS group. In contrast, the incidence of radiation toxicity was significantly decreased in the HF-SRS group compared to the SF-SRS group (8.0 versus 15.6%, p < 0.0001). CONCLUSION: HF-SRS results in better LC of large BMs while simultaneously reducing RN compared to SF-SRS. Thus, HF-SRS should be considered a priority for SF-SRS in patients with large BMs who are not suitable to undergo surgical resection.

Benign meningioma manifesting with acute subdural hematoma and cerebral edema: a case report and review of the literature.

BACKGROUND: Spontaneous subdural hematoma rarely presents with a hypervascular or malignant tumor but even less frequently in a benign tumor like meningioma. We encountered a patient with acute subdural hematoma associated with benign meningioma. Here, we report this case along with a review of previous reports, especially focusing on their clinical features and possible bleeding mechanisms. CASE PRESENTATION: A 53-year-old Asian woman presented with severe headache and progressive neurologic deterioration due to cerebral edema. The patient was submitted to open surgery for evacuation of the subdural hematoma and concurrent tumor removal on the ipsilateral parietal convexity. A hypervascular, encapsulated mass was identified during surgery and completely removed including the adjacent dura mater (Simpson grade 0). The tumor was histologically confirmed as an angiomatous meningioma (World Health Organization grade I). Her clinical course was uneventful after surgery. CONCLUSIONS: Although meningiomas are commonly benign according to their histological traits, they can lead to spontaneous bleeding and cause neurologically unstable condition. Therefore, meningiomas need to be considered as a cause of spontaneous subdural hematoma if radiologically suspicious, which should be reflected by proper management for a positive outcome.

An integrated disease-specific graded prognostic assessment scale for melanoma: contributions of KPS, CITV, number of metastases, and BRAF mutation status.

BACKGROUND: Stereotactic radiosurgery (SRS) remains a mainstay therapy in the treatment of melanoma brain metastases (BM). While prognostic scales have been developed for melanoma patients who underwent SRS treatment for BM, the pertinence of these scales in the context of molecularly targeted therapies remains unclear. METHODS: Through a multi-institutional collaboration, we collated the survival patterns of 331 melanoma BM patients with known BRAF mutation status treated with SRS. We established a prognostic scale that was validated in an independent cohort of 174 patients. All patients with BRAF mutations in this series were treated with BRAF inhibitors. Prognostic utility was assessed using Net Reclassification Index (NRI > 0) and integrated discrimination improvement (IDI) metrics. RESULTS: In a multivariate Cox proportional hazards model, BRAF mutation status, KPS, number of metastases, and cumulative intracranial tumor volume (CITV) independently contributed to survival prognostication for melanoma patients with SRS-treated BM (P < .05 for all variables). These variables were incorporated into a prognostic scale using the disease-specific graded prognostic assessment (ds-GPA) framework. This integrated melanoma ds-GPA scale was validated in 2 independent cohorts collated through a multi-institutional collaboration. In terms of order of prognostic importance, BRAF mutation status exerted the greatest influence on survival, while KPS, the number of metastases, and CITV exhibited comparable, lesser impacts. CONCLUSIONS: Optimal survival prognostication for SRS-treated patients with melanoma BM requires an integrated assessment of patient characteristics (KPS), tumor characteristics (CITV and number of metastases), and the mutational profile of the melanoma (BRAF mutation status).

Minimizing contamination in the use of personal protective equipment: Simulation results through tracking contamination and enhanced protocols.

BACKGROUND: Due to variations and the inadequate use of personal protective equipment (PPE), this study aimed to evaluate our enhanced PPE protocols for minimizing doffing contamination. METHODS: Among 3 PPE kits (simple, Level D, and Level C), 30 participants conducted the first simulation in their adapted way and the second following enhanced protocols. After donning, participants performed a 1-minute simulation of direct care on a patient simulator covered with fluorescent powder. For tracking contamination routes between doffing processes, fluorescent powder contamination was examined with ultraviolet lamps in the darkened room. RESULTS: Participants were mostly registered nurses (N = 27, 90%), female (87%), and on average 31.7 years old with 8.5 years of clinical experience. Among 61 total simulations, 32 had at least 1 contamination (52.5%); "Noticeable" level (40%) at the "hands-fingers" and "shirt" body areas were most frequent. For first and second simulations with identical PPE kits, compared to the first with adapted practice, the second with enhanced protocols showed a significant reduction in doffing contamination rates (72.7% vs 22.7%, P = .0009 for both Level C and D; 77.8% vs 27.8%, P = .0027 for Level D). CONCLUSIONS: Our enhanced protocols could significantly reduce contaminations. More studies are necessary to provide safer PPE protocol options.

Respiratory Specimen Collection Booth for COVID-19 Test: Efficiency Based Newly Introduced Facility.

Hospitals need to find a safe and rapid method for respiratory specimen collection as the number of patients suspicious for coronavirus disease -2019 (COVID-19) rapidly grows. Applied with significant infection control and prevention measures, a respiratory specimen collection booth was newly designed. The new respiratory specimen collection booth not only increased COVID-19 testing cases but also decreased personal protective equipment consumption.

Protection of Healthcare Workers Against COVID-19 at a Large Teaching Hospital in Seoul, Korea.

Thirteen patients with coronavirus disease 2019 (COVID-19) visited a university hospital in Seoul before recognizing their disease infections, causing contact with 184 hospital workers. We classified the patients into four risk levels and provided corresponding management measures. At 31 days after the last event, all screening laboratory results were negative, and no symptoms/signs were reported.

Radiological and clinical outcomes of endovascular coiling of proximal A1 aneurysms.

Aneurysms of the proximal anterior cerebral artery (A1) are rare. Of these A1 aneurysms, proximal A1 aneurysms are among the most challenging for endovascular coiling. This study aimed to evaluate the angiographic features and radiological and clinical outcomes of endovascular coiling of proximal A1 aneurysms. We recruited 38 patients with 38 proximal A1 aneurysms treated with endovascular coiling between September 2005 and April 2016. Baseline patient characteristics, aneurysm morphology, endovascular treatment techniques, immediate post-procedural radiological outcome, and follow-up clinical and radiological outcomes were evaluated, as were risk factors for recurrence. Sixteen proximal A1 aneurysms ruptured (42.1%). Six procedural complications (15.8%), including 5 thromboembolisms and 1 coil migration, were noted. There was no procedural morbidity or mortality. Immediate post-procedural radiological outcomes showed complete occlusion in 23, residual necks in 12, and residual sacs in 3 lesions. Follow-up angiographic outcomes were possible for 28 lesions (73.7%). Follow-up angiography showed sac recurrence in 3 (10.7%) and neck recurrence in 3 (10.7%) lesions. Retreatment was performed in 4 lesions (14.3%); all were treated by endovascular coiling. The presence of aneurysmal ruptures was only significant regarding recurrence in univariate logistic regression analysis. In our study, endovascular coiling of proximal A1 aneurysms was associated with a relatively high rate of procedural complications but not with procedural morbidity and mortality. The recurrence and retreatment rates of endovascular coiling of proximal A1 aneurysms were relatively high, and presence of rupture was significant for recurrence.

Relationship between Circadian Variation in Ictus of Aneurysmal Subarachnoid Hemorrhage and Physical Activity.

OBJECTIVE: The circadian pattern of the onset time of aneurysmal subarachnoid hemorrhage (aSAH) has been reported by various authors. However, the effect of the degree of physical exertion on the circadian pattern has not been studied in detail. Therefore, we conducted this study to investigate the effect of physical exertion on the circadian pattern of aSAH. METHODS: Of the 335 patients presenting with aSAH from January 2012 to December 2017, 234 patients with identifiable onset time and metabolic equivalent (MET) values were enrolled. The onset time of aSAH was divided into 4-hour intervals. The patient's physical exertion was then assessed on a scale between 1 and 8 METs using generally accepted MET values, and categorized into two groups-light exertion (1 to 4 METs) and moderate to heavy exertion (5 to 8 METs)-to determine the effect of the degree of physical exertion on the onset time distribution of aSAH. Multivariate analysis was used to calculate the odds ratio (OR) between the two groups to determine the effect of the degree of physical exertion on each set of time periods. RESULTS: There was a definite bimodal onset pattern that peaked at 08:00-12:00 hours followed by 16:00-20:00 hours (p <0.001). MET values at all time intervals were found to be significantly higher than the night time (00:00-04:00 hours) values (p<0.031). The MET value distribution showed a unimodal pattern that slightly differed from the bimodal distribution of the onset time of aSAH. There were no significant differences in the ORs of each time interval according to the degree of the MET value. CONCLUSION: This study reaffirmed that aSAH occurs in a bimodal pattern, especially showing the highest prevalence in the morning. Although aSAH could be related to daily activity, there were no significant changes in diurnal variations affected by the degree of physical exertion.

An Outbreak of KPC-Producing Klebsiella pneumoniae Linked with an Index Case of Community-Acquired KPC-Producing Isolate: Epidemiological Investigation and Whole Genome Sequencing Analysis.

Aims: A hospital outbreak of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPN) linked with an index case of community-acquired infection occurred in an urban tertiary care hospital in Seoul, South Korea. Therefore, we performed an outbreak investigation and whole genome sequencing (WGS) analysis to trace the outbreak and investigate the molecular characteristics of the isolates. Results: From October 2014 to January 2015, we identified a cluster of three patients in the neurosurgery ward with sputum cultures positive for carbapenem-resistant KPN. An epidemiological investigation, including pulsed-field gel electrophoresis analysis was performed to trace the origins of this outbreak. The index patient's infection was community acquired. Active surveillance cultures using perirectal swabbing from exposed patients, identified one additional patient with KPC-producing KPN colonization. WGS analyses using PacBio RSII instruments were performed for four linked isolates. WGS revealed a genetic linkage of the four isolates belonging to the same sequence type (ST307). All KPN isolates harbored conjugative resistance plasmids, which has blaKPC-2 carbapenemase genes contained within the Tn4401 "a" isoform and other resistance genes. However, WGS showed only three isolates among four KPC-producing KPN were originated from a common origin. Conclusions: This report demonstrates the challenge that KPC-2-producing KPN with the conjugative resistance plasmid may spread not only in hospitals but also in community, and WGS can help to accurately characterize the outbreak.

The 21-Item and 12-Item Versions of the Depression Anxiety Stress Scales: Psychometric Evaluation in a Korean Population.

PURPOSE: This study aimed to evaluate the psychometric properties of the Depression Anxiety Stress Scales 21 and 12 in a Korean population. METHODS: The Depression Anxiety Stress Scales were translated into Korean using a translation and back-translation technique, and the content validity was assessed by an expert panel. Participants were recruited from six community health centers (n = 431) and two community mental health centers (n = 50). A field test of the psychometric properties of the instruments was conducted using confirmatory factor analysis with bootstrap maximum likelihood estimation involving 1,000 samples, Pearson's analysis, t test, and Cronbach's α coefficient. RESULTS: Confirmatory factor analysis of the Depression Anxiety Stress Scales 21 and 12 supported both three-factor and second-order three-factor models. The Scales 21 and 12 satisfied convergent validity with the Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, and Perceived Stress Scale-10 and discriminant validity with the Rosenberg Self-Esteem Scale. The scores for the Depression Anxiety Stress Scales 21 and 12 were higher for the psychiatric group than for the nonpsychiatric group, confirming the presence of known-groups validity. The Depression Anxiety Stress Scales 21 and 12 exhibited moderate-to-strong correlations with the Negative Affect. Cronbach's α coefficients for the Depression Anxiety Stress Scales 21 and 12 were .93 and .90, respectively. CONCLUSION: The Depression Anxiety Stress Scales 21 and 12 appear to be acceptable, reliable, and valid instruments. However, the shorter Depression Anxiety Stress Scales 12 may be more feasible to use in a busy practice and also be less burdensome to respondents.

A new definition for wide-necked cerebral aneurysms.

BACKGROUND: Endovascular management of wide-necked aneurysms often requires assisted-techniques with adjunctive devices. Wide-necked aneurysm can be defined with a dome-to-neck ratio or aspect ratio; however, clinical definitions of wide-necked aneurysms vary. This study aimed to determine the most useful definition of wide-necked aneurysm to predict the need for an adjunctive device. METHODS: Among 552 cases of aneurysms, 343 (62.1%) and 209 (37.9%) cases of unruptured and ruptured aneurysms, respectively, were treated in a single institution. For each aneurysm, the (1) dome-to-neck ratio, (2) aspect ratio, and (3) K-ratio (defined as [dome height+maximum dome width]/[2×maximum neck width]) were measured. We statistically analyzed patient data to determine which of the three ratios was most predictive of the need for adjunctive devices. RESULTS: Among 552 cases of aneurysms, 277 (50.2%) and 275 (49.8%) cases were treated with and without adjunctive techniques, respectively. The mean dome-to-neck ratio, aspect ratio, and K-ratio were 1.17±0.39, 1.58±0.61, and 1.37±0.47, respectively. The K-ratio was the strongest predictor of the use of adjunctive devices (P<0.001), and 1.3 was the most appropriate K-ratio cut-off value (sensitivity, 72.9%; specificity, 63.6%). CONCLUSIONS: K-ratio was the most useful predictor of the need for adjunctive devices in the treatment of endovascular aneurysms. These results suggest that the K-ratio may be used to define wide-necked aneurysms requiring complicated management via adjunctive devices.

Does Neurosurgical Clipping or Endovascular Coiling Lead to More Cases of Delayed Hydrocephalus in Patients with Subarachnoid Hemorrhage?

OBJECTIVE: We investigated whether clipping or endovascular treatment (EVT) can reduce the incidence of delayed hydrocephalus. We also investigated whether additional procedures, namely lumbar drainage and extra-ventricular drainage (EVD), decrease the incidence of delayed hydrocephalus in patients with subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: One-hundred and fifty-two patients who had undergone an operation for SAH were enrolled in this study. Clinical data, radiological data, and procedural data were investigated. Procedural data included the operating technique (clipping vs. EVT) and the use of additional procedures (no procedure, lumbar drainage, or EVD). Delayed hydrocephalus was defined as a condition in which the Evan's index was 0.3 or higher, as assessed using brain computed tomography more than 2 weeks after surgery, requiring shunt placement due to neurological deterioration. RESULTS: Of the 152 patients, 45 (29.6%) underwent surgical clipping and 107 (70.4%) underwent EVT. Twenty-five (16.4%) patients developed delayed hydrocephalus. Age (p = 0.019), procedure duration (p = 0.004), and acute hydrocephalus (p = 0.030) were significantly correlated with the incidence of delayed hydrocephalus. However, the operation technique (p = 0.593) and use of an additional procedure (p = 0.378) were not significantly correlated with delayed hydrocephalus incidence. CONCLUSION: No significant difference in the incidence of delayed hydrocephalus was associated with operation technique or use of an additional procedure in patients with SAH. However, delayed hydrocephalus was significantly correlated with old age, long procedural duration, and acute hydrocephalus. Therefore, we recommend that additional procedures should be discontinued as soon as possible.

Gamma Knife Radiosurgery for Metastatic Brain Tumors with Exophytic Hemorrhage.

OBJECTIVE: Metastatic brain tumors (MBTs) often present with intracerebral hemorrhage. Although Gamma Knife surgery (GKS) is a valid treatment option for hemorrhagic MBTs, its efficacy is unclear. To achieve oncologic control and reduce radiation toxicity, we used a radiosurgical targeting technique that confines the tumor core within the hematoma when performing GKS in patients with such tumors. We reviewed our experience in this endeavor, focusing on local tumor control and treatment-associated morbidities. METHODS: From 2007 to 2014, 13 patients with hemorrhagic MBTs were treated via GKS using our targeting technique. The median marginal dose prescribed was 23 Gy (range, 20-25). GKS was performed approximately 2 weeks after tumor bleeding to allow the patient's condition to stabilize. RESULTS: The primary sites of the MBTs included the liver (n=7), lung (n=2), kidney (n=1), and stomach (n=1); in two cases, the primary tumor was a melanoma. The mean tumor volume was 4.00 cm3 (range, 0.74-11.0). The mean overall survival duration after GKS was 12.5 months (range, 3-29), and three patients are still alive at the time of the review. The local tumor control rate was 92% (tumor disappearance 23%, tumor regression 46%, and stable disease 23%). There was one (8%) instance of local recurrence, which occurred 11 months after GKS in the solid portion of the tumor. No GKS-related complications were observed. CONCLUSION: Our experience shows that GKS performed in conjunction with our targeting technique safely and effectively treats hemorrhagic MBTs. The success of this technique may reflect the presence of scattered metastatic tumor cells in the hematoma that do not proliferate owing to the inadequate microenvironment of the hematoma. We suggest that GKS can be a useful treatment option for patients with hemorrhagic MBTs that are not amenable to surgery.