In male-factor infertility, the great challenge is often to extract sperm from the male body. Once sperm has been obtained, it can then be used for IUI, ICSI, or IVF (described below). The various sperm-collection procedures must all overcome the same difficulties:
- 1.Getting enough sperm. Typically, 5-8 million sperm are needed for IUI. If it is not possible to get this number of sperm, it may be necessary to use more difficult techniques like ICSI, so as to make the most of the sperm which have been obtained.
2.The sperm must be functional. If the sperm are dead (necrospermia) or otherwise ineffective, extracting them will be useless.
3.The procedure should involve as little risk and discomfort for the patient as possible.
Now we’ve seen what sperm extraction techniques must achieve, let’s see what the options are. There are three forms of surgery to extract sperm, which are collectively known as ‘sperm aspiration’. These are:
- PESA sperm extraction
MESA (Mirosurgical Epididymal Sperm Extraction)
TESE (Testicular Sperm Extraction)
TESA (Testicular Sperm Aspiration)
PESA and MESA: sperm extraction from the epididymis
PESA and MESA extract sperm from the epididymis, an organ just above the testes which stores sperm. With PESA, this is done by inserting a needle into the epididymis more or less at random. The hope is that the needle will randomly find some sperm. This does work reasonably often, but it rarely succeeds in getting enough sperm for use in insemination. PESA also carries the risk of hitting a blood vessel, which can cause all kinds of complications.
MESA is an alternative to PESA which is more invasive, but generally results in more sperm being collected. In MESA, the epididymis is opened through surgery, and examined under a microscope. The doctor can then cut open one Sf the tiny tubes which store the sperm, and can then extract large quantities of sperm. As MESA requires surgery and specialized equipment, it is more expensive than PESA, and there are less clinics capable of performing it.
TESE and TESA: sperm extraction from the testicles.
The other two procedures, TESE and TESA, take sperm from the testicle itself rather than from the epididymis. This is essential when the sperm never reaches the epididymis (this situation is true in most cases of non-obstructive azoospermia). Otherwise, it is not ideal, since if something goes wrong here it would affect the testicle itself.
The difference between TESE and TESA is similar to that between MESA and PESA. In TESA, a needle is used to remove a small section of the testicle. This section can then be taken off to a laboratory, where the sperm is extracted from it. The problem is that, as with PESA, it is hard to tell exactly what the needle will catch. Again, there is a risk of hitting a blood vessel, something which is made more serious by the risk that this could cut off the blood supply to the testicle.
TESE is also a biopsy of the testicle, but it is an open rather than a needle biopsy. In other words, the doctor will manually cut off a small section of the testicle.
Sperm aspiration is not usually used to deal with a simple inability to ejaculate. As explained above, damage to the spinal cord or to the rest of the nervous system can inhibit ejaculation, even when the genitals themselves are perfectly healthy. In theory, it would be possible to extract sperm with MESA or the other techniques discussed above, but this is not necessary. Instead, mechanical means are used to stimulate ejaculation.
In the simplest case, a mechanical vibrator can be used on the penis. This stimulates the nerves in the region, and can provoke ejaculation as a reflex reaction. The method here is basically the same as that which makes you jerk your leg when you are tapped on the knee: the nervous system for that part of the body works by itself, without needing to deal with the brain.
This simple system will not always work. In particular, it requires a complete reflex arc: the nerves running from the genitals to the spinal cord must be intact. When basic vibratory stimulation fails, the next tool is called Electro-ejaculation. Under general anesthetic, an electrical anal probe is used to stimulate the nerves around the prostate.
There are many cases in which a man can anticipate becoming infertile in the future. A typical example is if you are undergoing cancer treatments which involve chemotherapy. Chemotherapy usually targets fast-dividing cells in the body, because this is the best way to target cancer. A significant side-effect of chemotherapy is therefore damage to other fast growing cells. Chemotherapy patients lose their hair and gut linings and their sperm production grinds to a halt.
Another example is a vasectomy. While it is not advisable to undergo vasectomy unless you are convinced that you will never want to father a child, storing sperm allows at least some room for reconsideration if you change your mind later in life. Many clinics will therefore advise men to store a sperm sample before they undergo vasectomy.
Men who are undergoing one of the artificial sperm extraction techniques described above will often have the extracted sperm stored. This enables them to undergo the extraction procedure only once, but store enough sperm for several attempts at insemination. This is crucial given the relatively low success rates of some infertility treatments, and the risks and hassle involved in sperm extraction procedures.
Finally, sperm which will be used for donor insemination is generally frozen after collection. As well as avoiding the logistical nightmare of trying to procure ‘just-in-time’ sperm for immediate fertility treatments, this allows more time to monitor the health of sperm donors, and so to screen out any donors whose sperm might be carrying defects.
The process of freezing sperm is now well understood, and can be done with very little adverse impact on the quality of the sperm. Frozen sperm can be kept for many years.
Surgery is an option in some cases of obstructive azoospermia that is, in situations where the sperm is being held back by a physical blockage. The most common case of this is vasectomy reversal. The sperm ducts which were tied off during the original vasectomy are repaired or bypassed, and a good number of patients are then able to conceive through normal intercourse.
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