This fact sheet outlines what is involved in Percutaneous Epididymal Sperm Aspiration (PESA) and Testicular Sperm Aspiration (TESA). These are techniques that can be used to extract sperm if a man does not have sperm in his semen (azoospermia).
Azoospermia is a condition where there are no sperm at all in a man’s ejaculated semen and there can be various reasons for this.
Sperm production and delivery involves a system of tubes within the male reproductive system. Sperm are initially produced in the testis in fine tubes called seminiferous tubules. In each testis these tubules are connected to a larger coiled tube called the epididymis in which sperm are held for a short while after production.
Azoospermia can be caused by an abnormality or blockage in the epididymis or the vas deferens. This is referred to as obstructive azoospermia. In these cases, sperm are being produced in the testes, they just can’t get out.
Sometimes however, sperm production in the seminiferous tubules does not occur at all or is happening at such a low level that sperm are not detectable in the ejaculate. This is referred to as non-obstructive azoospermia.
Using surgical procedures to try and extract sperm from the epididymis (PESA) or to dissect it out of tubules from the testis (TESA) can be an effective way of diagnosing what is causing the azoospermia.
The possible causes of lack of sperm in your ejaculate include:
Testicular problems resulting in poor sperm production. These can be caused by various factors such as genetic issues, previous infection (e.g. mumps), maldescended testes.
An irreversible obstruction of the genital tract (possibly caused by a previous infection, trauma or surgery)
Congenital absence (absence from birth) of the vas deferens, which is common in carriers of cystic fibrosis
A previous vasectomy or an unsuccessful vasectomy reversal.
You are at risk of injury or death (for example, you’re a member of the Armed Forces who is being deployed to a war zone).
The number of sperm retrieved through PESA or TESA is usually very low compared to the number present in an ejaculate, so the sperm usually need to be used in combination with a specific type of IVF called ICSI (Intracytoplasmic sperm injection).
Your partner will undergo an IVF cycle and, once her eggs have been collected (usually the same day as your PESA or TESA), your sperm will be injected directly into her eggs (a process called ICSI). The fertilised eggs are then cultured for a few days in the laboratory before a healthy embryo is transferred into your partner’s uterus.