Background: Azoospermia, the absence of sperm in ejaculated semen, is the most severe form of male factor infertility and is present in approximately 5% of all investigated infertile couples. The advent of intra-cytoplasmic sperm injection (ICSI), however, has transformed treatment of this type of severe male factor infertility. Sperm can be retrieved for ICSI from either the epididymis or the testis depending on the type of azoospermia.
Objectives: To evaluate the efficacy of the various surgical retrieval techniques for men with obstructive or non obstructive azoospermia prior to ICSI.
Search strategy: We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched 12 Jan 2005), Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2004), MEDLINE (1966 to Nov 2004), EMBASE (1980 to Dec 2004), and Biological Abstracts (1980 to Nov 2004) and reference lists of articles.
Selection criteria: Randomised controlled trials (RCTs) comparing the effectiveness of sperm retrieval techniques in men with azoospermia prior to ICSI. Due to the lack of RCTs, non-randomised trials that used the participants as their own control, were also considered in the review but not included in the meta-analysis.
Data collection and analysis: Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.
Main results: Two trials involving 98 men were included. The first small RCT had 59 participants and compared two epididymal techniques. The trial gave limited evidence that microsurgical epididymal sperm aspiration (MESA) achieved significantly lower pregnancy (One pregnancy in 29 procedures compared with seven pregnancies in 30 procedures, OR 0.19, 95% CI 0.04 to 0.83) and fertilisation rates (OR 0.16, 95% CI 0.05 to 0.48) than the micropuncture with perivascular nerve stimulation technique. The other RCT comparing two testicular techniques in 39 participants gave no statistically significant evidence about the superiority of the ultrasound guided aspiration technique compared to the aspiration technique without ultrasound guidance. TSA with ultrasound resulted in pregnancy in 3 out of 16 participants and TSA without ultrasound in four pregnancies with 23 participants (OR 1.10, 95% CI 0.21 to 5.74)
Authors' conclusions: There is insufficient evidence to recommend any specific sperm retrieval technique for azoospermic men undergoing ICSI. In the absence of evidence to support more invasive or more technically difficult methods the reviewers recommend the least invasive and simplest technique available. Further randomised trials are warranted, preferably multi-centred trials. The classification of azoospermia as obstructive and non-obstructive appears to be relevant to a successful clinical outcome so a distinction according to the cause azoospermia is important for future clinical trials.