The newest of the aspiration techniques is testicular sperm retrieval (TESA – TESE). In this procedure, a small amount of testis tissue is taken by biopsy under local anesthesia. It is a breakthrough in that it demonstrates that sperm do not have to “mature” and pass through the epididymis in order to fertilize an egg. Because of their immaturity, however, testicular sperm need ICSI.
Testicular sperm extraction is indicated for patients in whom there is a blockage in the epididymis very near the testis (either from prior surgery, infection or from birth), or a blockage within the ducts of the testes (efferent ductules).
It is also used for men with extremely poor sperm production, in which so few sperm are produced that they cannot reach the ejaculate. Pregnancies are now routine in cases of poor sperm production, but there is some concern with the use of this sperm because in most cases the underlying condition causing the poor sperm production is still unknown.
Therefore, in these cases, it must be realized that the condition which may have caused the infertility, may be transmitted to the progeny. Recently, even spermatids (round cells that eventually become a sperm with a tail) have been used to achieve pregnancies with ICSI.
However, this has raised much speculation and concern about the use of genetic material from a still-evolving germ cell for clinical purposes before the system has been appropriately investigated and its genetic stability examined in animal models.
Spermatid injections are currently considered experimental procedures. One drawback of testis sperm is that is does not freeze as readily as epididymal or vasal sperm and thus it is more likely that the male partner will need to undergo repeated procedures for each IVF attempt.
Sperm Extraction Procedures
Intracytoplasmic sperm injection (ICSI) has revolutionized the treatment of male infertility. The sperm requirement for egg fertilization has dropped from hundreds of thousands for in vitro fertilization (IVF), to one viable sperm required for ICSI when combined with IVF. This has led to the recent development of aggressive new surgical techniques to provide viable sperm for egg fertilization from men with low or no sperm count.
This has also pushed urologists beyond the ejaculate and into the male reproductive tract to find sperm for biologic pregnancies. Presently, sources of sperm in otherwise azoospermic (no ejaculated sperm) patients include the vas deferens, epididymis and testicle using sperm aspiration techniques.
Sperm aspiration techniques involve the use of minor surgical procedures to collect sperm from organs within the genital tract. These techniques are indicated for men in whom the transport of sperm is not possible because the ductal system that normally carries sperm to the ejaculate is absent (i.e. congenital absence of the vas deferens) or unable to be reconstructed.
Most recently, sperm has been fairly reliably extracted (60-70% of the time) from the testes of men with sperm production problems of such severity that no sperm is found in the ejaculatory ducts.
It is important to realize, however, that in vitro fertilization (IVF) technology is required to achieve a pregnancy with the vast majority of these extraction procedures, and thus success rates are intimately tied to a complex and complementary program of assisted reproduction for both partners.