Development of a greenhouse gas - air pollution interactions and synergies model for Korea (GAINS-Korea).

This study aimed to create Greenhouse Gas - Air Pollution Interactions and Synergies (GAINS)-Korea, an integrated model for evaluating climate and air quality policies in Korea, modeled after the international GAINS model. GAINS-Korea incorporates specific Korean data and enhances granularity for enabling local government-level analysis. The model includes source-receptor matrices used to simulate pollutant dispersion in Korea, generated through CAMx air quality modeling. GAINS-Korea's performance was evaluated by examining different scenarios for South Korea. The business as usual scenario projected emissions from 2010 to 2030, while the air quality scenario included policies to reduce air pollutants in line with air quality and greenhouse gas control plans. The maximum feasible reduction scenario incorporated more aggressive reduction technologies along with air quality measures. The developed model enabled the assessment of emission reduction effects by both greenhouse gas and air pollutant emission reduction policies across 17 local governments in Korea, including changes in PM2.5 (particulate matter less than 2.5 µm) concentration and associated benefits, such as reduced premature deaths. The model also provides a range of visualization tools for comparative analysis among different scenarios, making it a valuable resource for policy planning and evaluation, and supporting decision-making processes.

Current status of ultrasonography in national cancer surveillance program for hepatocellular carcinoma in South Korea: a large-scale multicenter study.

Background/Aim: Abdominal ultrasonography (USG) is recommended as a surveillance test for high-risk groups for hepatocellular carcinoma (HCC). This study aimed to analyze the current status of the national cancer surveillance program for HCC in South Korea and investigate the effects of patient-, physician-, and machine-related factors on HCC detection sensitivity. Methods: This multicenter retrospective cohort study collected surveillance USG data from the high-risk group for HCC (liver cirrhosis or chronic hepatitis B or C >40 years of age) at eight South Korean tertiary hospitals in 2017. Results: In 2017, 45 experienced hepatologists or radiologists performed 8,512 USG examinations. The physicians had a mean 15.0±8.3 years of experience; more hepatologists (61.4%) than radiologists (38.6%) participated. Each USG scan took a mean 12.2±3.4 minutes. The HCC detection rate by surveillance USG was 0.3% (n=23). Over 27 months of follow-up, an additional 135 patients (0.7%) developed new HCC. The patients were classified into three groups based on timing of HCC diagnosis since the 1st surveillance USG, and no significant intergroup difference in HCC characteristics was noted. HCC detection was significantly associated with patient-related factors, such as old age and advanced fibrosis, but not with physician- or machine-related factors. Conclusions: This is the first study of the current status of USG as a surveillance method for HCC at tertiary hospitals in South Korea. It is necessary to develop quality indicators and quality assessment procedures for USG to improve the detection rate of HCC.

Effects of intermediate frequency electromagnetic fields: a review of animal studies.

PURPOSE: Many novel devices such as induction cookers or wireless power transfer produce electromagnetic fields (EMFs) in the intermediate frequency (IF) range (300 Hz to 10 MHz) and it is very meaningful for summarizing the bioeffects of IF-EMF research, particularly animal studies. This review takes into account experimental studies that used murine models to study the health effects of exposure to IF-EMF. The analyses included here use data available in the literature published from January 1988 to August 2021 including the animal studies about general adverse effects, tumorigenic effects, and effects on developmental stages. The studies that linked IF-EMF exposure during pregnancy or neonatal stage to behavioral and cognition changes were included. Additionally, this review also covers the effects of IF-EMF on gene expression patterns in the brain, behavior patterns associated with learning and memory, and immune function. CONCLUSIONS: Although most studies have suggested that IF-EMF is harmless, some adverse effects have been reported after exposure at developmental stages and prolonged exposure. Compared to extremely low frequency (ELF) or radiofrequency (RF) EMF bands, studies on health effects with more diverse perspectives of IF-EMF have not been conducted. Therefore, performing more research should be necessary using the latest biomedical tools. From this point of view, a comprehensive review of IF-EMF studies, particularly animal studies, will provide a valuable basis for further risk analysis in humans.

Glossopharyngeal Neuralgia.

Glossopharyngeal neuralgia (GPN) is a rare disease that must be differentiated from trigeminal neuralgia. The purpose of this article is to provide a comprehensive review of anatomy, pathophysiology, diagnostic criteria, and several options of treatment for GPN. Lessons learned through our experience of treating GPN are presented in detail, as well as cases of misdiagnosis and diagnostic pitfalls. Microvascular decompression (MVD) should be primarily considered for medically intractable GPN. Techniques employed in MVD for GPN are categorized and described. Especially, we underscore the advantages of the 'transposition' technique where insulating material is positioned 'off' the root entry zone (REZ), instead of 'on' it. We believe this 'off-the-REZ' technique can fundamentally prevent recurrence, if applicable. In addition, Gamma Knife radiosurgery can be an alternative option when a patient is ineligible for MVD, though it is categorized as a destructive procedure.

Effect of radiofrequency exposure on body temperature: Real-time monitoring in normal rats.

Radiofrequency radiation (RFR) can generate heat in living organisms. In this study, we monitored the body temperature of healthy animals during RFR exposure in real time using an implantable iButton data logger. A reverberation chamber system for small animals was used for this radiofrequency (RF) exposure in vivo study. Healthy male Sprague-Dawley rats were divided into two groups: with versus without iButton implantation (n = 20 per group). Each group was further divided into a sham-exposed and RF-exposed group (n = 10 per subgroup). Rats were exposed to a 1,760-MHz long-term evolution (LTE) signal in the reverberation chamber system at a whole-body average specific absorption rate of 0 W/kg (sham-exposed) or 4 W/kg (RF-exposed) for 6 h. The body temperature of iButton-implanted rats was recorded using an intraperitoneally implanted iButton every minute over 6 h of RF exposure, whereas that of non-implanted rats was measured directly using a rectal thermometer immediately before and after the 6-h RF exposure period. The temperature values measured by the two types of thermometers were significantly positively correlated (r = 0.63, P < 0.01, linear regression), and changes in body temperatures recorded in iButton-implanted and non-implanted rats measured using two thermometers after 6 h of RF exposure were maintained within <1°C (P = 0.87, general linear model, followed by univariate model). Similar results were obtained for rectal thermometer measurements (P = 0.12, paired t-test). These results suggest that RF exposure at a whole-body average specific absorption rate of 4 W/kg does not induce significant changes in body temperature in healthy rats over a 6-h RF exposure period.

An International Collaborative Animal Study of the Carcinogenicity of Mobile Phone Radiofrequency Radiation: Considerations for Preparation of a Global Project.

Radiofrequency radiation (RFR) was classified as a "possible" human carcinogen in 2011, which caused great public concern. A carcinogenicity study by the National Toxicology Program (NTP) found Code Division Multiple Access-and Global System for Mobile Communications-modulated mobile phone RFR to be carcinogenic to the brain and heart of male rats. As part of an investigation of mobile phone carcinogenesis, and to verify the NTP study results, a 5-year collaborative animal project was started in Korea and Japan in 2019. An international animal study of this type has two prerequisites: use of the same study protocol and the same RF-exposure system. This article discusses our experience in the design of this global study on radiofrequency electromagnetic fields (RF-EMFs).© 2022 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society.

Relationship between the dynamics of non-alcoholic fatty liver disease and incident diabetes mellitus.

The aim of the current study was to evaluate the association between changes in non-alcoholic fatty liver disease (NAFLD) over time and risk of incident diabetes mellitus (DM). In total, 3047 subjects without underlying DM were followed up for 14 years from the Anseong-Ansan cohort. NAFLD status was determined biennially using the hepatic steatosis index (HSI), and subjects were clustered into seven groups according to changes in HSI, body mass index (BMI), and homeostatic model assessment of insulin resistance (HOMA-IR): none, persistent, transient, transient resolved, resolved, incident, and recurrent NAFLD (Groups 1-7, respectively). Predictive abilities were compared between the dynamics of HSI and single time points. Regarding the changes in HSI, the risk of incident DM was highest in Group 2 (hazard ratio [HR] 2.710; P < 0.001), followed by Groups 7 (HR 2.062; P < 0.001) and 3 (HR 1.559; P = 0.027). The predictive ability for DM was powerful in order of HOMA-IR, HSI and BMI. The dynamics of NAFLD were less predictive of incident DM than single time-point NAFLD. In conclusion, NAFLD is more useful than BMI in predicting incident DM. However, NAFLD status at single time points can better predict incident DM than dynamic changes in HSI.

Effect of direct-acting antivirals for hepatitis C virus-related hepatocellular carcinoma recurrence and death after curative treatment.

Background/Aim: There has been a long-standing debate about the association of directacting antiviral (DAA) therapy and hepatocellular carcinoma (HCC) recurrence. This study aimed to investigate the association between DAA therapy and HCC recurrence after curative therapy. Methods: We retrospectively enrolled 1,021 patients with HCV-related (hepatitis C virus) HCC who underwent radiofrequency ablation (RFA), liver resection, or both as the first treatment modality from January 2007 to December 2016 and without a history of HCV therapy before HCC treatment from a nationwide database. The effect of HCV treatment on HCC recurrence and all-cause mortality was also investigated. Results: Among the 1,021 patients, 77 (7.5%) were treated with DAA, 14 (1.4%) were treated with interferon-based therapy, and 930 (91.1%) did not receive HCV therapy. DAA therapy was an independent prognostic factor for lower HCC recurrence rate (hazard ratio [HR], 0.04; 95% confidence interval [CI], 0.006-0.289; P=0.001 for landmarks at 6 months after HCC treatment and HR, 0.05; 95% CI, 0.007-0.354; P=0.003 for landmarks at 1 year). Furthermore, DAA therapy was associated with lower all-cause mortality (HR, 0.049; 95% CI, 0.007-0.349; P=0.003 for landmarks at 6 months and HR, 0.063; 95% CI, 0.009-0.451; P=0.006 for landmarks at 1 year). Conclusions: DAA therapy after curative HCC treatment can decrease HCC recurrence and all-cause mortality compared to interferon-based therapy or no antiviral therapy. Therefore, clinicians should consider administering DAA therapy after curative HCC treatment in patients with HCV-related HCC.

Risk Prediction Model Based on Magnetic Resonance Elastography-Assessed Liver Stiffness for Predicting Posthepatectomy Liver Failure in Patients with Hepatocellular Carcinoma.

BACKGROUND/AIMS: Posthepatectomy liver failure (PHLF) is a major complication that increases mortality in patients with hepatocellular carcinoma after surgical resection. The aim of this retrospective study was to evaluate the utility of magnetic resonance elastography-assessed liver stiffness (MRE-LS) for the prediction of PHLF and to develop an MRE-LS-based risk prediction model. METHODS: A total of 160 hepatocellular carcinoma patients who underwent surgical resection with available preoperative MRE-LS data were enrolled. Clinical and laboratory parameters were collected from medical records. Logistic regression analyses were conducted to identify the risk factors for PHLF and develop a risk prediction model. RESULTS: PHLF was present in 24 patients (15%). In the multivariate logistic analysis, high MRE-LS (kPa; odds ratio [OR] 1.49, 95% confidence interval [CI] 1.12 to 1.98, p=0.006), low serum albumin (≤3.8 g/dL; OR 15.89, 95% CI 2.41 to 104.82, p=0.004), major hepatic resection (OR 4.16, 95% CI 1.40 to 12.38, p=0.014), higher albumin-bilirubin score (>-0.55; OR 3.72, 95% CI 1.15 to 12.04, p=0.028), and higher serum α-fetoprotein (>100 ng/mL; OR 3.53, 95% CI 1.20 to 10.40, p=0.022) were identified as independent risk factors for PHLF. A risk prediction model for PHLF was established using the multivariate logistic regression equation. The area under the receiver operating characteristic curve (AUC) of the risk prediction model was 0.877 for predicting PHLF and 0.923 for predicting grade B and C PHLF. In leave-one-out cross-validation, the risk model showed good performance, with AUCs of 0.807 for all-grade PHLF and 0. 871 for grade B and C PHLF. CONCLUSIONS: Our novel MRE-LS-based risk model had excellent performance in predicting PHLF, especially grade B and C PHLF.

Mobile Phone Use and Time Trend of Brain Cancer Incidence Rate in Korea.

This study evaluated the time trends in mobile phone subscriber number by mobile network generation (G) and brain cancer incidence by type in Korea. We obtained data from the Information Technology Statistics of Korea (1984-2017) and Korea Central Cancer Registry (1999-2017). The average annual percent change was estimated using Joinpoint regression analysis. We evaluated 29,721 brain cancer cases with an age-standardized incidence rate (ASR) of 2.89/100,000 persons. The glioma and glioblastoma annual ASR significantly increased in 2.6% and 3.9% of males and 3.0% and 3.8% of females, respectively. The ASR for frontal lobe involvement was the highest. The ASR of gliomas of unspecified grade annually increased by 7.8%; those for unspecified topology and histology decreased. The incidence of glioma, glioblastoma, frontal, temporal, and high-grade glioma increased among those aged ≥60 years. No association was observed between the mobile phone subscriber number and brain cancer incidence in Korea. Furthermore, long-term research is warranted because of the latency period of brain cancer. © 2021 Bioelectromagnetics Society.

Effects of emission trading schemes on corporate carbon productivity and implications for firm-level responses.

Since the South Korean government enacted the Emission Trading Scheme (ETS), companies have been striving to simultaneously improve productivity and reduce carbon emissions, which represent conflicting goals. We used firm-level emissions and corporate variables to investigate how ETS enactment has affected carbon productivity, which is a firm-level revenue created per unit of carbon emission. Results showed that firm-level carbon productivity increased significantly under the ETS, and such a trend was more evident for high-emission industries. We also found that companies with high carbon productivity were (1) profitable, (2) innovative, and (3) managed by CEOs with experience in environmental fields. These findings suggest that to achieve the conflicting goals of increasing corporate profits while reducing emissions, firms have to invest in green technologies, and such decisions are supported by green leadership. Our findings also have implications for corporate leadership; data highlight the importance of managing human resources and deploying investment policies to respond to ETS.

Biological Effects of Exposure to a Radiofrequency Electromagnetic Field on the Placental Barrier in Pregnant Rats.

The placenta protects the fetus against excessive stress-associated maternal cortisol during pregnancy. We studied whether exposure to radiofrequency electromagnetic field (RF-EMF) radiation during pregnancy can cause changes in dams and their placentas. Pregnant Sprague-Dawley rats were divided into cage-control, sham-exposed, and RF-exposed groups. They were exposed to RF-EMF signals at a whole-body specific absorption rate of 4 W/kg for 8 h/day from gestational Day 1 to 19. Levels of cortisol in the blood, adrenal gland, and placenta were measured by enzyme-linked immunosorbent assay. Levels of adrenocorticotropic hormone and corticotropin-releasing hormone were monitored in maternal blood. Expression levels of placental 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2) messenger RNA (mRNA) were measured by reverse transcription polymerase chain reaction. Morphological changes in the placenta were analyzed using hematoxylin and eosin staining. Fetal parts of the placenta were measured using Zen 2.3 blue edition software. Maternal cortisol in circulating blood (RF: 230 ± 24.6 ng/ml and Sham: 156 ± 8.3 ng/ml) and the adrenal gland (RF: 58.3 ± 4.5 ng/ml and Sham: 30 ± 3.8 ng/ml) was significantly increased in the RF-exposed group (P < 0.05). Placental cortisol was stably maintained, and the level of placental 11ß-HSD2 mRNA expression was not changed in the RF-exposed group. RF-EMF exposure during pregnancy caused a significant elevation of cortisol levels in circulating blood; however, no changes in the placental barrier were observed in pregnant rats. Bioelectromagnetics. © 2021 Bioelectromagnetics Society.

Independent Risk Factors for Hepatocellular Carcinoma Recurrence after Direct-Acting Antiviral Therapy in Patients with Chronic Hepatitis C.

Background/Aims: This study was performed to evaluate the efficacy of direct-acting antivirals (DAAs) in Korean patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) and to investigate the risk factors associated with HCC recurrence. Methods: A total of 100 patients with HCV-related HCC, who were treated with DAAs between May 2015 and December 2016, were recruited from seven university hospitals in Korea. Claim data of 526 patients with HCC obtained from the Health Insurance Review and Assessment Service in South Korea were used for external validation of the results. Results: Among the 100 patients, 88% achieved a sustained virological response (SVR) 12 weeks after the end of DAA therapy (SVR12), and 37% experienced HCC recurrence after DAA therapy. Short last HCC treatment durability (<12 months) before DAA commencement was independently associated with HCC recurrence (hazard ratio [HR], 2.89; p=0.011). In the nationwide validation cohort, 20.3% of the patients experienced HCC recurrence. The last HCC treatment with a noncurative method, a short last HCC treatment durability (<12 months), and a longer total duration of HCC treatment (≥18 months) were independently related with HCC recurrence (HR 3.73, p<0.001; HR 3.34, p<0.001; and HR 1.74, p=0.006; respectively). Conclusions: DAA therapy showed an acceptable SVR12 rate in patients with HCV-related HCC. Short last HCC treatment durability (<12 months) was associated with HCC recurrence after DAA therapy. This finding suggests that the last HCC treatment durability is an important predictor of HCC recurrence after DAA therapy.

Influences of exposure to 915-MHz radiofrequency identification signals on serotonin metabolites in rats: a pilot study.

PURPOSE: The influences of radiofrequency electromagnetic exposure on animal health, particularly on serotonin metabolism, are not well-elucidated. In this in vivo study, we studied the influences of exposure to radiofrequency identification (RFID) signals on serotonin metabolism. MATERIALS AND METHODS: Twenty-two male Sprague-Dawley rats were assigned to sham (n = 10) and RFID-exposed (n = 12) groups. Rats in the RFID-exposed group were exposed to RFID signals at an average whole-body specific absorption rate of 2 W/kg for 8 h/day, 5 days/week for 2 weeks. Before and after RFID exposure, 24-h urine was collected from each rat. Urinary tryptophan, 5-hydroxytryptophan, serotonin, 5-hydroxyindoleacetic acid, and 5-methoxyindole-3-acetic acid concentrations were examined using gas chromatography-mass spectrometry, and changes in the patterns of values were compared between the two groups. RESULTS: Urinary levels of serotonin decreased by 20% (p = .041, Student's t-test) and 40% (p = .024, Student's t-test) in both the sham and RFID-exposed groups, respectively. The level of 5-methoxyindole-3-acetic acid decreased by 30% in the RFID-exposed group (p = .039, Student's t-test). CONCLUSION: Our results indicate that exposure to RFID signals at a specific absorption rate of 2 W/kg is sufficient to alter serotonin metabolism in rats regardless of whether the exposure level is considered biohazardous.

Effect of Exposure to a Radiofrequency Electromagnetic Field on Body Temperature in Anesthetized and Non-Anesthetized Rats.

Exposure to a radiofrequency (RF) signal at a specific absorption rate (SAR) of 4 W/kg can increase the body temperature by more than 1 °C. In this study, we investigated the effect of anesthesia on the body temperature of rats after exposure to an RF electromagnetic field at 4 W/kg SAR. We also evaluated the influence of body mass on rats' body temperature. Rats weighing 225 and 339 g were divided into sham- and RF-exposure groups. Each of the resulting four groups was subdivided into anesthetized and non-anesthetized groups. The free-moving rats in the four RF-exposure groups were subjected to a 915 MHz RF identification signal at 4 W/kg whole-body SAR for 8 h. The rectal temperature was measured at 1-h intervals during RF exposure using a small-animal temperature probe. The body temperatures of non-anesthetized, mobile 225 and 339 g rats were not significantly affected by exposure to an RF signal. However, the body temperatures of anesthetized 225 and 339 g rats increased by 1.9 °C and 3.3 °C from baseline at 5 and 6 h of RF exposure, respectively. Three of the five 339 g anesthetized and exposed rats died after 6 h of RF exposure. Thus, anesthesia and body mass influenced RF exposure-induced changes in the body temperature of rats. Bioelectromagnetics. 2020;41:104-112. © 2019 Bioelectromagnetics Society.

Causes of Death among Persons Affected by Leprosy in Korea, 2010-2013.

In addition to the complications of leprosy, people affected by leprosy (PALs) can suffer from chronic diseases. We evaluated the recent pattern of deaths among Korean PALs and compared it with that in the general population. We analyzed the death certificate data of 1,359 PALs from 2010 through 2013. The all-cause and cause-specific standardized mortality ratio (SMR) and standardized mortality with 95% CI were calculated. Malignancy had the highest standardized mortality, with 130.9 deaths per 100,000 persons, followed by cardiovascular diseases (CVDs; 85.5 deaths) and respiratory diseases (38.2 deaths). Of malignancies, liver cancer caused the greatest number of cancer deaths (40.0 deaths). The all-cause mortality of PALs was significantly lower than that in the general population, corresponding to an SMR of 0.84 (95% CI 0.79-0.88). Deaths from malignancy and CVDs were significantly lower, corresponding to SMRs (95% CIs) of 0.88 (0.79-0.98) and 0.75 (0.67-0.84), respectively. The death rates for lung and stomach cancers were lower, whereas mortality due to liver cancer was higher, with an SMR of 1.79 (95% CI 1.43-2.22). Except for liver cancer and infection, the causes of mortality of PALs tend to be lower than that in the general population. The most common underlying cause of death in PALs was stroke, followed by ischemic heart disease, liver cancer, and pneumonia.

Comparison of the Clinical Characteristics and Outcomes between Leprosy-Affected Persons in Sorokdo and the General Population Affected by Chronic Hepatitis C in Korea.

Background/Aims: Patients with Hansen's disease are the most vulnerable to hepatitis C. However, no data on the treatment efficacy of direct-acting antiviral agents (DAAs) are available in this group. Therefore, we elucidated the prevalence and clinical outcomes of hepatitis C in persons affected by leprosy in Sorokdo, Jeollanam-do, Korea. Methods: We retrospectively included 50 leprosy patients with positive hepatitis C virus (HCV) RNA test results (group A) hospitalized at the Sorokdo National Hospital from May 2016 to March 2018 and 73 patients with chronic hepatitis C who were treated with DAAs at the Chonnam National University Hospital (group B) from May 2016 to December 2017. Results: Overall, at the Sorokdo National Hospital, positive HCV antibody and HCV RNA rates were 18.4% and 11.0%, respectively. The mean participant age was 76.5±7 years, and 58% of participants were men. The genotypes were type 1b in 44% (22 out of 50) and type 2 in 56% (28 out of 50). Sustained virologic response was achieved at a rate of 95.5% (21/22) in genotype 1b and 92.9% (26/28) in genotype 2 patients. Ribavirin-induced hemolytic anemia occurred in 57.1% (16/28) of patients with genotype 2. Among these, 28.5% (8/28) received blood transfusions. Conclusions: Treatment efficacy was not different between the leprosy-affected population and the general population. However, severe ribavirin-induced hemolytic anemia requiring transfusion was present in 28.5% of genotype 2 patients. Therefore, we suggest ribavirin-free DAAs for the treatment of genotype 2 hepatitis C in leprosy-affected persons in the future.

Effects of exposure to electromagnetic field from 915 MHz radiofrequency identification system on circulating blood cells in the healthy adult rat.

We investigated whether exposure to the 915 MHz radiofrequency identification (RFID) signal affected circulating blood cells in rats. Sprague-Dawley rats were exposed to RFID at a whole-body specific absorption rate of 2 W/kg for 8 h per day, 5 days per week, for 2 weeks. Complete blood counts were performed after RFID exposure, and the CD4+ /CD8+ ratio was determined by flow cytometry. The number of red blood cells (RBCs) and the values of hemoglobin, hematocrit, and RBC indices were increased in the RFID-exposed group compared with those in the cage-control and sham-exposed groups (P < 0.05). However, the RBCs and platelet numbers were within normal physiologic response ranges. The number of white blood cells, including lymphocytes, was decreased in RFID-exposed rats. However, there was no statistically significant difference between the sham-exposed and RFID-exposed groups in terms of T-cell counts or CD4+ /CD8+ ratio (P > 0.05). Although the number of circulating blood cells was significantly altered by RFID exposure at a whole-body specific absorption rate of 2 W/kg for 2 weeks, these changes do not necessarily indicate that RFID exposure is harmful, as they were within the normal physiological response range. Bioelectromagnetics. 39:68-76, 2018. © 2017 Wiley Periodicals, Inc.

Microvascular Decompression for Glossopharyngeal Neuralgia: Clinical Analyses of 30 Cases.

OBJECTIVE: We present our experience of microvascular decompression (MVD) for glossopharyngeal neuralgia (GPN) and evaluate the postoperative outcomes in accordance with four different operative techniques during MVD. METHODS: In total, 30 patients with intractable primary typical GPN who underwent MVD without rhizotomy and were followed for more than 2 years were included in the analysis. Each MVD was performed using one of four different surgical techniques: interposition of Teflon pieces, transposition of offending vessels using Teflon pieces, transposition of offending vessels using a fibrin-glue-coated Teflon sling, and removal of offending veins. RESULTS: The posterior inferior cerebellar artery was responsible for neurovascular compression in 27 of 30 (90%) patients, either by itself or in combination with other vessels. The location of compression on the glossopharyngeal nerve varied; the root entry zone (REZ) only (63.3%) was most common, followed by both the REZ and distal portion (26.7%) and the distal portion alone (10.0%). In terms of detailed surgical techniques during MVD, the offending vessels were transposed in 24 (80%) patients, either using additional insulation, offered by Teflon pieces (15 patients), or using a fibrin glue-coated Teflon sling (9 patients). Simple insertion of Teflon pieces and removal of a small vein were also performed in five and one patient, respectively. During the 2 years following MVD, 29 of 30 (96.7%) patients were asymptomatic or experienced only occasional pain that did not require medication. Temporary hemodynamic instability occurred in two patients during MVD, and seven patients experienced transient postoperative complications. Neither persistent morbidity nor mortality was reported. CONCLUSION: This study demonstrates that MVD without rhizotomy is a safe and effective treatment option for GPN.

Bioglue-Coated Teflon Sling Technique in Microvascular Decompression for Hemifacial Spasm Involving the Vertebral Artery.

OBJECTIVE: Microvascular decompression (MVD) for hemifacial spasm (HFS) involving the vertebral artery (VA) can be technically challenging. We investigated the therapeutic effects of a bioglue-coated Teflon sling technique on the VA during MVD in 42 cases. METHODS: A bioglue-coated Teflon sling was crafted by the surgeon and applied to patients in whom neurovascular compression was caused by the VA. The radiologic data, intra-operative findings with detailed introduction of the procedure, and the clinical outcomes of each patient were reviewed and analyzed. RESULTS: The 42 patients included in the analysis consisted of 22 females and 20 males, with an average follow-up duration of 76 months (range 24-132 months). Intraoperative investigation revealed that an artery other than the VA was responsible for the neurovascular compression in all cases : posterior inferior cerebellar artery (PICA) in 23 patients (54.7%) and anterior inferior cerebellar artery (AICA) in 11 patients (26.2%). All patients became symptom-free after MVD. Neither recurrence nor postoperative neurological deficit was noted during the 2-year follow-up, except in one patient who developed permanent deafness. Cerebrospinal fluid (CSF) leak occurred in three patients, and one required dural repair. CONCLUSION: Transposition of the VA using a bioglue-coated Teflon sling is a safe and effective surgical technique for HFS involving the VA. A future prospective study to compare clinical outcomes between groups with and without use of this novel technique is required.