Abstract
Background/Objectives: Varicocele repair can improve semen parameters and pregnancy rates in appropriately selected men; however, persistence or recurrence remains a common cause of treatment failure with ongoing infertility or scrotal pain. Because mechanisms and definitions vary across studies, counseling and salvage selection can be challenging. This review synthesizes contemporary evidence on why varicocele recur and provides an anatomy-informed approach to evaluation and retreatment. Methods: A narrative evidence synthesis was performed using PubMed/MEDLINE, prioritizing clinical practice guidelines, systematic reviews, meta-analyses, and contemporary adult and adolescent clinical series addressing mechanisms of failure, diagnostic workup, and outcomes of salvage microsurgery and endovascular therapy. Results: Recurrence rates vary by technique and follow-up, with the lowest rates reported in contemporary microsurgical subinguinal series. The dominant drivers of failure are incomplete venous control and complex reflux pathways, including duplicated internal spermatic veins and missed collaterals such as cremasteric, external spermatic, gubernacular, and deferential veins. Clinical examination remains central; Doppler ultrasonography is most useful when pain persists or semen parameters and testicular growth do not improve. Venography can define culprit channels in complex or multiply treated cases and enables targeted embolization. Retreatment achieves high anatomic success with consistent improvements in semen parameters and meaningful pregnancy rates in available series, with modality-specific complication profiles. Conclusions: Recurrent varicocele should be managed with structured reassessment that links venous anatomy and the index procedure to the salvage option. Microsurgical redo is generally favored after non-microscopic repairs, whereas endovascular occlusion is often preferred after prior surgery or when venographic mapping is needed.