In this review, we tried to systematize all the evidence (from PubMed [MEDLINE], Scopus, Cochrane Library, EBSCO, Embase, and Google Scholar) from 1993 to 2021 on the predictors of microsurgical varicocelectomy efficacy in male infertility treatment. Regarding the outcomes of varicocele repair, we considered semen improvement and pregnancy and analyzed them separately. Based on the 2011 Oxford CEBM Levels of Evidence, we assigned a score to each trial that studied the role of the predictor. We systematized the studied predictors based on the total points, which were, in turn, calculated based on the number and quality of studies that confirmed or rejected the studied predictor as significant, into three levels of significance: predictors of high, moderate, and low clinical significance. Preoperative total motile sperm count (TMSC) coupled with sperm concentration can be a significant predictor of semen improvement and pregnancy after varicocelectomy. In addition, for semen improvement alone, scrotal Doppler ultrasound (DUS) parameters, sperm DNA fragmentation index (DFI), and bilateral varicocelectomy are reliable predictors of microsurgical varicocelectomy efficacy.
Keywords: male infertility; microsurgical varicocelectomy; predictor; pregnancy; semen; varicocele.