Sperm are produced inside the testes and they mature and become motile, as they travel through the epididymis. During ejaculation, the mature sperms are carried from the epididymis to the penis along the vas deferens. Normally this ejaculated sperm is used for fertilisation, however in a subgroup of infertile male there is no sperm present in the ejaculate leading to azoospermia. Any anatomical, infectious, traumatic or developmental anomaly like congenital absence of vas deferens in this passage for sperms can lead to obstructive oligospermia/ azoospermia (~40% of all cases of azoospermia). On the other hand, non-obstructive azoospermia can result from absence or very poor sperm production inside testes (~60% cases of azoospermia) and can result from hormonal abnormalities, varicocele or testicular failure.Until very recently there was no effective treatment for men suffering from azoospermia. In obstructive azoospermia the reason for the absence of sperm in the ejaculate is physical and in general, does not involve the process of sperm production. Therefore in most cases surgically retrieved sperm are normal in their function and fertilization rates and pregnancy rates are similar to those obtained using ICSI on ejaculated sperm. Men with congenital absence of vas should be investigated for genetic diseases like cystic fibrosis.
There are three methods of surgically retrieving sperm from the testis
1. Percutaneous Epididymal Sperm Aspiration (PESA)
PESA is a simple technique to obtain sperms for Intra Cytoplasmic Sperm Injection (ICSI) in men with infertility due to obstructive azoospermia. PESA is generally carried out under local anaesthesia and in most of the cases it’s performed only on one side, but sometimes it becomes necessary to do this simultaneously on both the testes.
After taking informed consent from the couple, giving local anaesthesia and cleaning scrotum with antiseptic solution, the doctor locates the vas deferens and then inserts a fine needle into the vas deferens, while an assistant pulls back the plunger to aspirate seminal fluid. The embryologist examines the seminal fluid to locate motile sperms in the sample. The procedure may need to be attempted again until motile sperm have been found. After the procedure the man will be asked to wear a very tight pair of underpants to provide support to the scrotum and avoid pain and swelling of scrotum.
The procedure is usually performed just prior to the ovum retrieval in the female partner. In case, no sperms are found in the aspirate, egg retrieval may be cancelled or donor sperms used for fertilization.
2. Testicular Sperm Extraction (TESE)/ Trans Epididymal Sperm Aspiration (TESA)
This procedure involves giving a small incision over the testes and taking out a small piece of seminiferous tubule tissue to isolate sperms from the tissue sample. This procedure is used for sperm extraction in patients with severe obstructive oligospermia. It can also be used to find some live and motile sperms in patients with non-obstructive azoospermia, in which there may still be some small areas of sperm production in otherwise non-functional testes. The number of viable sperms isolated is generally smaller than with PESA and the sperms are generally not fit for freezing. As with PESA, TESA is also performed just prior to the egg retrieval so that ICSI can be performed simultaneously. In cases, where even TESA/ TESE doesn’t yield live and mobile sperm, egg retrieval can either be cancelled or the retrieved eggs can be frozen.
In some cases, the procedure yields only immature sperms. These immature sperms cannot be used for ICSI because the fertilization rates with immature sperm are very poor and even if fertilization does occur, there is high possibility of miscarriage following transfer of such embryos. Not only this, use of such immature sperms can lead to serious chromosomal disorders in the offspring.
3. Microdissection TESE
This is one of the most advanced techniques of sperm extraction in men with non-obstructive azoospermia that is in men having problem with sperm production. Microdissection TESE is performed in the operating room and under general anaesthesia using an operating microscope. It is based on the principle that in azoospermic men there may be some islands of spermatogenic activity, which are not identifiable with naked eyes but can be identified using a microscope and can be dissected away. The tubules in such islands of normal tissue appear healthier, dilated and more opaque in comparison to adjoining abnormal tubules. Using the magnification of the operating microscope, the surgeon picks only the healthy looking seminiferous tubules thus optimising the chances of sperm retrieval. This process can help in retrieving sperms in men with previously failed testicular biopsies and also reduces the amount of testicular tissue removed during the procedure. The extra sperms retrieved by Microdissection TESE are cryopreserved for future IVF/ICSI also.
Microdissection TESE is carefully coordinated with the female partner’s egg retrieval, and is performed either the day before egg retrieval or on the same day. This allows each partner to be there for the other’s procedure.