P-070 The effect of surgical interventions in sperm DNA fragmentation: a systematic review and meta-analysis

Abstract

Abstract Study question Do surgical interventions improve sperm DNA fragmentation? Summary answer Orchiectomy, bariatric surgery and varicocelectomy improve sperm DNA fragmentation. What is known already Sperm DNA fragmentation, which is known to be one of the functional alterations that harms men’s fertile potential, is caused by several factors, and one of the most important is oxidative stress, caused by accumulation of reactive oxygen species (ROS) beyond the physiological limits of the organism. Some examples of diseases that cause this increase in ROS are testicular tumors, obesity and varicocele. Once they all have surgical corrections, the aim of this study was to observe if orchiectomy, bariatric surgery and varicocelectomy had a positive impact in sperm DNA fragmentation. Study design, size, duration A systematic review was developed, including 33 articles: 1 about orchiectomy, 4 about bariatric surgery, and the remaining ones about varicocelectomy. After the review was finished, a meta-analysis was conducted with all the numeric information extracted from the articles. The study was registered on PROSPERO database and was performed based on PRISMA guideline. Participants/materials, setting, methods Data extraction was made by two reviewers independently, and all the information was tabulated in a systematic spreadsheet. 7 articles were excluded, because they did not meet the inclusion criteria: they either included analysis of adolescent spermatogenesis or did not include analysis of sperm DNA fragmentation, and 5 articles were excluded from statistical analysis due to the studies’ designs and lack of essential statistical data. The statistical analysis was conducted by dmetar, metafor e meta. Main results and the role of chance The studies were carried out with men whose seminal samples were analysed before and after surgical intervention. The type of intervention (orchiectomy, bariatric surgery or varicocelectomy) and the way sperm DNA fragmentation was analysed (Terminal deoxynucleotidyl transferase dUTP nick end labeling – TUNEL, Cometa Assay or The Sperm Chromatin Structure Assay – SCSA) were not moderators of the estimated effect. However, the effect estimated increased according to the duration of the follow-up. When duration of follow-up was short (up to six months), there was no effect of interventions on sperm DNA fragmentation. The effect was greater when the duration was average (between six and nine months) and long (more than nine months). There was a reduction in sperm DNA fragmentation with interventions (effect estimated [confidence range 95%] = -1.22 [-1.65; -0.78]; p < 0.001). Despite different techniques were used to analyse sperm DNA fragmentation, the present study showed an improvement in this functional alteration after surgical interventions. Limitations, reasons for caution The small number of participants included in each article analysed, the heterogeneity between the follow-up time and the lack of quality numeric information in literature are possible limitations of this study. Besides, the fact that varicocelectomy had a bigger weight in this study must be analysed critically. Wider implications of the findings Therefore, this study is considered an important source for consistent and reliable information about sperm DNA fragmentation and the effect of surgical interventions on it. It is necessary to expand the studies on this topic, mostly due to the lack of randomized clinical trials. Trial registration number not applicable