Epididymal microsurgery: current techniques and new horizons.

Surgical treatment for obstructive azoospermia was introduced about 30 years ago with the development of Bayle's vasoepididymal fistula technique (Bayle: Enc Med Chir 41:435, 1966). More recently this has been replaced by single tubule end-to-end microvasoepididymal bypass procedures with improved success rates. We describe the use of animal models in the development and application of a modified end-to-end microanastomosis technique in which the vas deferens is attached to a single surface convolution of the ductus epididymidis. In comparison with other microvasoepididymostomy (micro-VE) procedures, this technique results in less postoperative scarring and allows for easier access to the epididymis in those patients requiring subsequent epididymal surgery. With this procedure 60% of patients produced spermatozoa after operation, and 10% of 102 patients have so far achieved pregnancies. For patients, such as those with congenital absence of the vasa deferentia, whose infertility cannot be corrected by microvasoepididymal surgery, we describe a microaspiration procedure that can be used to collect spermatozoa from the epididymis for use in in vitro fertilization (IVF). This procedure has a low success rate at present, with an 18% fertilization and 3% pregnancy rate per cycle. Improvements in treatment procedures for aspirated sperm samples, such as the use of motility stimulators and in vitro maturation by coculture with epididymal tubule segments before IVF, may enhance the success for this technique. Microinjection of sperm collected by epididymal microaspiration into oocytes may be an alternative method of treatment for these patients in the future. Two procedures (microepididymoepididymostomy and the vas bridge bypass) that are currently being modelled in the rabbit may provide new directions for epididymal microsurgery and for examining epididymal function. Although the two methods are technically more difficult than standard micro-VE procedures, preliminary studies are encouraging and suggest a future role for these techniques in treating obstructive azoospermia. Such techniques make use of the epididymis distal to the obstruction site and may be particularly important in improving the success of surgery for obstructive azoospermic patients with high-level obstructions in whom sperm quality following micro-VE surgery is often poor.