Background: A varicocele is an, almost exclusively left-sided, varicosity of the pampiniform plexus of the spermatic cord, forming a tangle of distended blood vessels in the scrotum. Although the concept that varicocele causes male subfertility and therefore varicocelectomy cures male subfertility has been around for almost fifty years now, the mechanisms by which varicocele would affect fertility have not yet been satisfactorily explained, and neither have the mechanisms by which varicocelectomy would resolve subfertility. Furthermore, it has been questioned whether a causal relation exists at all between the distension of the pampiniform plexus and impairment of fertility.
Objectives: To evaluate the effect of varicocele treatment on pregnancy rate in subfertile couples.
Search strategy: Relevant trials were identified in the Cochrane Menstrual Disorders and Subfertility Group's specialised register of controlled trials. A MEDLINE search, using the group's search strategy, was performed for the period 1966-2000. Also, hand searching was performed of 22 specialist journals in the field from their first issue till 2000. Cross references and references from review articles were checked.
Selection criteria: RCTs were included if they were relevant to the clinical question posed, if they reported pregnancy rates as an outcome measure, and if they reported data in treated (surgical ligation or radiological embolization of the internal spermatic vein) and untreated groups.
Data collection and analysis: Six studies met the inclusion criteria for this review. One (Nieschlag 1995/1998) was an extension of a previously published study (Nieschlag 1995/1998), which left five studies for analysis (Nilsson 1979; Breznik 1993; Madgar 1995; Yamamoto 1996; Nieschlag 1995/1998). The results of a WHO megatrial are awaited but as yet are unavailable. The WHO data will be added if and when they will have become available. All five only included men from couples with subfertility problems, one (Madgar 1995) excluded men with sperm counts <5 mill/mL, three (Nilsson 1979; Breznik 1993; Yamamoto 1996) also included men with normal semen analysis. One study (Yamamoto 1996) specifically addressed only men with subclinical varicoceles as diagnosed by thermography. Potentially relevant trials were screened independently by two authors (JE and JC). Any differences of opinion were resolved by consensus meeting (none occurred for this review). Studies were excluded from meta-analysis if they made comparisons other than those specified above.
Main results: One trial (Madgar 1995) reported a statistically significant improvement in pregnancy rate following high ligation of the left spermatic vein. None of the other four studies showed individually a significant effect on pregnancy rates of varicocele treatment over no-treatment (Nilsson 1979; Breznik 1993; Yamamoto 1996), or over counseling only (Nieschlag 1995/1998). The combined RR (Relative Risk; random effects method) of the five studies is 1.06 (95%CI 0.57-1.94), the Peto OR (Odds Ratio) is 1.15 (95%CI 0.73-1.83).
Reviewer's conclusions: Insufficient evidence exists that treatment of varicocele in men from couples with otherwise unexplained subfertility does improve the couple's spontaneous pregnancy chances.