Surgical Sperm Collection (PESA, TESE, MESA)

This information should be read in conjunction with the sections on intra cytoplasmic sperm microinjection (ICSI) and invitro fertilization (IVF) on this website. This information outlines the broad issues associated with SSC and a patient’s specialist doctor will advise patients of their individual treatment which may differ from the information given here.

Overview of the male reproductive system

The function of the male reproductive system is to produce, store and transport the sperm outside the body. The organs that produce sperm are the testes. Sperm production begins with immature sperm cells that grow and develop within the seminiferous tubules. These tubes are very tiny and the sperm inside them are not fully mature. As a result they are unable to move on their own. As they travel along the length of the epididymis they mature and become motile. During ejaculation they are carried from the epididymis to the penis along the vas deferens (Figure 1).

Until recently there was no treatment available for men who have a complete absence of sperm in the ejaculate (azoospermia), and it has been estimated that about 10–15% of cases of male infertility are due to azoospermia. Azoospermia has many causes; some of the causes are called obstructive meaning that there is a blockage in the sperm delivery system. Other causes are non obstructive meaning that there is an absence or a very marked reduction of sperm production in the testes. It is strongly recommended that all patients with azoospermia are reviewed by a urologist.

Obstructive Azoospermia

Obstructive azoospermia accounts for about 40% of azoospermia cases. Obstruction may result from defects in any of the ducts (passage ways) involved in the sperm delivery system. The obstruction may be either congenital (you were born with it) or acquired (you were not born with it). Vasectomy is a common form of male contraception, and is the most common form of obstruction. With this the vas deferens is cut forming an acquired obstruction. Another cause is infection, which can scar the epididymis.

Congenital obstruction can be due to either a malformation or the absence of a ductal structure. Congenital absence of the vas (CAV) is a genetic disorder associated with cystic fibrosis and with this the vas deferens is either absent or malformed. If CAV has been diagnosed your doctor will advise you on the correct course of action. 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. Also the incidence of birth defects does not appear different to men without congenital obstruction of sperm.

NOTE: If patients have been diagnosed with CAV their doctor will discuss the inheritance of this genetic disorder and the effect on any children born.

Non-obstructive Azoospermia

The three major causes for reduced sperm production are hormonal problems, testicular failure and varicocele (benign testicular cysts). A significant proportion of men with non-obstructive azoospermia have testicular failure caused by chromosomal abnormalities such as Klinefelter’s syndrome or abnormalities of the Y chromosome. The doctor will discuss in detail what the problem is and how best it might be treated. If azoospermia is due to chromosomal abnormalities the concern is that male offspring could inherit the disorder, and therefore the implications of inheritance of the genetic disorder need to be considered.

Surgical Sperm Collection (SSC)

There are two methods of surgically retrieving sperm from the testis, needle biopsy or open biopsy. A needle biopsy (PESA) involves inserting a needle into the testis and pulling (aspirating) fluid or small amounts of tissue from the epididymis out. In contrast, an open biopsy (TESE and MESA) involves cutting the testis and removing the fluid or tissue directly.

PESA is a less invasive procedure in which sperm are collected from the epididymis by needle aspiration. PESA is more commonly used as it can be performed in a fertility clinic without the need for hospital day surgery or a general anaesthetic. If PESA is unsuccessful then the more invasive TESE and MESA procedures may be considered. Both TESE and MESA involve a general anaesthetic administered in operating room conditions.

Percutaneous Epididymal Sperm Aspiration (PESA)

PESA is a simple technique to obtain sperm for intra cytoplasmic sperm injection (ICSI) in men who have an obstruction of the vas deferens, either due to vasectomy or other obstruction. To minimize scarring and damage, PESA usually is attempted on one side only. However, if insufficient sperm are obtained it may be necessary to aspirate from both sides. Sufficient sperm for ICSI is obtained in about 80% of attempts. In about 10% of cases enough suitable sperm is found for cryopreservation.

PESA may be performed at the fertility centre rather than in a hospital operating room.

PESA is performed under local anaesthetic. An anaesthetic is injected into the scrotum by the specialist to make the area numb. When this has been achieved the doctor will swab the scrotum with a warm antiseptic. The doctor will examine the testes to locate the vas deferens by gently feeling the scrotum. A small needle will be inserted into the vas deferens and the doctor will instruct the nurse assisting to draw back on the plunger in order to aspirate seminal fluid. When fluid is obtained it is passed to the andrologist to be examined for motile (moving) sperm. The procedure may need to be attempted again until motile sperm have been found.

PESA is usually performed just prior to the woman’s oocyte collection (on the same day). After the procedure the man will be asked to wear a very tight pair of underpants to provide support to the scrotum. There is no other special preparation for the patient.

Testicular Sperm Extraction (TESE) and Microsurgery Epididymal Sperm Aspiration (MESA)

TESE involves taking a small piece of tissue from the testis and isolating the sperm from the seminiferous tubule (Figure 2). The number of sperm isolated is often very small (usually less than with MESA) and as a general rule these sperm cannot be cryostored. The procedure is thus performed typically about twenty four hours prior to the egg collection procedure.

MESA involves aspiration of sperm from the epididymis with a fine needle (Figure 2). It is a surgical procedure and is carried out under a general anesthetic. Sperm collected using this procedure are often of poor quality but are usually suitable for cryostorage. One aspiration may provide enough sperm for several attempts at IVF using ICSI. MESA can be performed well in advance of any proposed IVF procedure.

In some cases live sperm will not be obtained from a surgical sperm collection. The options are:

1. the IVF oocyte (egg) collection may be cancelled, or

2. any oocytes collected can be frozen,

3. attempt at a another surgical sperm collection at a later date or

4. donor sperm can be used.

It is advisable for patients to discuss these options with their doctor prior to commencing an IVF procedure in case live sperm is not obtained.

If patients decide to use donor sperm for an IVF cycle, they will need to discuss this with the fertility clinic well before the oocyte collection to allow for counselling, a cooling off period and provision of the donor sperm.

Non-use of immature sperm

In some cases of non obstructive azoospermia only immature sperm are obtained. Fertilisation rates with immature sperm are often quite poor and even zero. Even if fertilisation does occur and pregnancy follows an embryo transfer, the rate of miscarriage is two to three times higher than in pregnancies obtained using mature sperm. Recent studies have shown that this result may be linked to an increase in the level of a chromosomal disorder called mosaicism, which is itself linked to sperm immaturity. For this reason most fertility clinics do not inject immature sperm or sperm that are immotile. If mature motile sperm cannot be located then the procedure will usually be abandoned. Please discuss the consequences of this with your doctor before commencing a surgical sperm collection procedure.

Consents

A consent form requesting the above techniques must be signed before commencing a surgical sperm collection.