Evers J L, Collins J A, Vandekerckhove P
Department of Obstetrics & Gynaecology, Research Institute GROW, Academisch ziekenhuis Maastricht & Maastricht University, P.O. Box 5800, Maastricht, Netherlands, 6202 AZ.
Cochrane Database Syst Rev. 2001(1):CD000479. doi: 10.1002/14651858.CD000479.
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.
To evaluate the effect of varicocele treatment on pregnancy rate in subfertile couples.
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.
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.
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.
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.
精索静脉曲张几乎仅发生于左侧,是精索蔓状静脉丛的静脉曲张,在阴囊内形成一团扩张的血管。尽管精索静脉曲张导致男性生育力低下,因此精索静脉结扎术可治愈男性生育力低下这一概念已存在近五十年,但精索静脉曲张影响生育的机制尚未得到令人满意的解释,精索静脉结扎术解决生育力低下的机制也未明确。此外,有人质疑蔓状静脉丛扩张与生育力受损之间是否存在因果关系。
评估精索静脉曲张治疗对不育夫妇妊娠率的影响。
在Cochrane月经紊乱和不育症小组的对照试验专门登记册中识别相关试验。使用该小组的检索策略,对1966年至2000年期间进行了MEDLINE检索。此外,对该领域的22种专业期刊从创刊号至2000年进行了手工检索。检查了交叉引用和综述文章中的参考文献。
如果随机对照试验与所提出的临床问题相关,将妊娠率作为结局指标报告,并且报告了治疗组(精索内静脉手术结扎或放射栓塞)和未治疗组的数据,则纳入该试验。
六项研究符合本综述的纳入标准。一项研究(Nieschlag 1995/1998)是先前发表研究(Nieschlag 1995/1998)的扩展,因此留下五项研究进行分析(Nilsson 1979;Breznik 1993;Madgar 1995;Yamamoto 1996;Nieschlag 1995/1998)。世界卫生组织一项大型试验的结果有待公布,但目前尚未获得。如果世界卫生组织的数据可用,将予以补充。所有五项研究仅纳入了有生育问题夫妇中的男性,一项研究(Madgar 1995)排除了精子计数<500万/mL的男性,三项研究(Nilsson 1979;Breznik 1993;Yamamoto 1996)还纳入了精液分析正常的男性。一项研究(Yamamoto 1996)专门针对经热成像诊断为亚临床精索静脉曲张的男性。两名作者(JE和JC)独立筛选潜在相关试验。如有任何意见分歧,通过共识会议解决(本综述未出现分歧)。如果研究进行的比较不是上述指定的比较,则排除在荟萃分析之外。
一项试验(Madgar 1995)报告,左侧精索静脉高位结扎后妊娠率有统计学意义的提高。其他四项研究均未单独显示精索静脉曲张治疗对妊娠率的影响显著高于未治疗组(Nilsson 1979;Breznik 1993;Yamamoto 1996),或高于仅咨询组(Nieschlag 1995/1998)。五项研究的合并相对危险度(随机效应法)为1.06(95%可信区间0.57 - 1.94),Peto比值比为1.15(95%可信区间0.73 - 1.83)。
对于其他原因不明的不育夫妇中的男性,治疗精索静脉曲张是否能提高夫妇的自然受孕几率,现有证据不足。