Absolute asthenozoospermia and ICSI: what are the options?

BACKGROUND Complete asthenozoospermia, i.e. 100% immotile spermatozoa in the ejaculate, is reported at a frequency of 1 of 5000 men. Its diagnosis implies a poor fertility prognosis even with ICSI. It is extremely important to distinguish between two different groups of patients with complete asthenozoospermia, i.e. virtual or absolute asthenozoospermia. With the former group having some motile spermatozoa after extensive processing of the semen, absolute asthenozoospermia can be associated with metabolic deficiencies, ultrastructural abnormalities of the sperm flagellum, necrozoospermia otherwise it can be idiopathic. In the management of persistent absolute asthenozoospermia, it is very important to elucidate its nature and whenever possible to correct the potential causes. METHODS We reported data published in the literature on the aetiology of absolute asthenozoospermia and the different techniques to improve ICSI outcome. We propose an algorithm for diagnosis and treatment of this condition. RESULTS Different results regarding fertilization, cleavage and pregnancy rate have been published in patients with absolute asthenozoospermia undergoing ICSI. However, the results vary widely depending on the sperm origin and the technique applied for immotile sperm selection. The percentage of viable spermatozoa varies between 0 and 100%. CONCLUSIONS Absolute immotile spermatozoa is one of the most important causes of reduced fertilization and pregnancy rates after ICSI and different techniques are used to improve ICSI outcomes. However, it still remains unclear which is the best technique to improve the pregnancy outcomes in these couples.