Many men without sperm in the seminal fluid may have sperm in the testis or in a region next to the testicles called epididymis.
The reasons why sperm may not be present in the seminal fluid are:
- There may be clogging in the production system so that, while sperm is produced cannot go out and fertilize the egg. This is known as obstructive azoospermia.
In the case of obstructive azoospermia, sperm may be collected from the epididymis by applying a mild surgical procedure called microsurgical epididymis for sperm collection (MBA). If the urologist applying the method does not find sperm in the epididymis, during the same procedure, he can try to find sperm in the testicles. This procedure is called transdermal aspiration of testicular sperm (TESA).
- Very few sperm can be produced in the testicles. This is known as azoospermia of non-obstructive etiology.
In the case of men who have non-obstructive azoospermia, the TESA procedure is required. The TESE process is similar, i.e. the collection of testicular sperm with testicle biopsy.
Sperm collected from aspiration, by any method, is always of a lower quality than that of ejaculation, and requires the use of ICSI or IMSI methods for higher rates of fertility.