Long lasting effect on testes following methylene blue injection in laparoscopic lymphatic sparing varicocelectomy.

OBJECTIVE: Injection of methylene blue to testis has been shown to have adverse effect in animal studies but it is still being used frequently as lymphatic mapping agent during lymphatic sparing varicocelectomy in adolescent varicoceles. We aim to report postoperative ultrasound changes after subaortic injection of methylene blue in human testes. STUDY DESIGN: A retrospective observational study of consecutive patients under 18 years old undergoing laparoscopic varicocelectomy from August 2017 to August 2021 was performed. Demographics such as age, symptoms, pre-operative testicular volume was collected. Primary outcome was change on testicular ultrasound at 3, 6, 12 months after the operation. Secondary outcome was testicular volume difference between affected and unaffected testes, and growth rate of affected testis at 1 year after the operation. RESULTS: Fifty-eight patients were included, with median age of 15 years old (IQR 11-18 years). Thirty-one patients had non-lymphatic sparing varicocelectomy (Group A) and 27 patients had lymphatic sparing varicocelectomy (Group B). There was no statistical difference between the mean testicular volume difference between the two groups, but hydrocele rate was significantly higher in Group A (16% vs 0%, p = 0.03). In group B, 6 patients (22.2%, p = 0.005) developed testicular change detectable by ultrasound. No statistical difference could be demonstrated for median testicular size difference (between affected and unaffected testes) at 1 year between group with and without ultrasound change (-23% vs 0%, p = 0.36). Median follow up time was 20.4 months (IQR 5-32 months). DISCUSSION: Varicocele treatments improve testicular volume and increase total sperm concentration and lymphatic sparing surgery significantly decreased post-operative hydrocele rates [2]. Different agents have been used to delineate lymphatic vessels and one commonly used agent is methylene blue [10,15-16]. However it has been shown in other animal studies that intraparenchymal injection of methylene blue to rat testis result in degenerative changes [18]. Our study is the first to describe post-operative changes of human testes on imaging after lymphatic sparing varicocelectomy with subdartoic injection of methylene blue. Six patients (22.2%) demonstrated new onset testicular changes on post-operative ultrasound. Although no statistically significant testicular volume reduction was seen in the group with change on imaging, these observations may serve as a surrogate marker for testicular injury or reduced testicular function. It will be desirable for future studies if we can investigate it further with hormonal markers or semen analysis after puberty has been reached. CONCLUSION: Lymphatic sparing procedure reduced post-operative hydrocele in adolescent varicocele, however long-lasting effect on testis is evident with subdartoic injection of methylene blue. This agent must be used with caution and long term follow up of these patients are needed.

Global Prevalence of Helicobacter pylori Infection: Systematic Review and Meta-Analysis.

BACKGROUND & AIMS: The epidemiology of Helicobacter pylori infection has changed with improvements in sanitation and methods of eradication. We performed a systematic review and meta-analysis to evaluate changes in the global prevalence of H pylori infection. METHODS: We performed a systematic search of the MEDLINE and EMBASE databases for studies of the prevalence of H pylori infection published from January 1, 1970 through January 1, 2016. We analyzed data based on United Nations geoscheme regions and individual countries. We used a random effects model to calculate pooled prevalence estimates with 95% confidence intervals (CIs), weighted by study size. We extrapolated 2015 prevalence estimates to obtain the estimated number of individuals with H pylori infection. RESULTS: Among 14,006 reports screened, we identified 263 full-text articles on the prevalence of H pylori infection; 184 were included in the final analysis, comprising data from 62 countries. Africa had the highest pooled prevalence of H pylori infection (70.1%; 95% CI, 62.6-77.7), whereas Oceania had the lowest prevalence (24.4%; 95% CI, 18.5-30.4). Among individual countries, the prevalence of H pylori infection varied from as low as 18.9% in Switzerland (95% CI, 13.1-24.7) to 87.7% in Nigeria (95% CI, 83.1-92.2). Based on regional prevalence estimates, there were approximately 4.4 billion individuals with H pylori infection worldwide in 2015. CONCLUSIONS: In a systematic review and meta-analysis to assess the prevalence of H pylori infection worldwide, we observed large amounts of variation among regions-more than half the world's population is infected. These data can be used in development of customized strategies for the global eradication.