ICSI including MESA/TESE

ICSI (pronounced "ick-see") is the most innovative method of fertility medicine. ICSI is always the right approach if the fusion of egg and sperm cells is impaired or the sperm quality does not permit test-tube fertilisation without any assistance. A minimum of 50,000 to 100,000 functioning and fast-moving sperm per egg cell are needed if in vitro fertilisation is to succeed. If these numbers are not reached, ICSI is the therapy of choice.

In terms of treatment for the patient, ICSI is no different to in vitro fertilisation. The differences are in the laboratory. Thereby, each egg is injected with a single sperm. The egg is held in place with a thick glass pipette, while a very fine pipette is used to inject one sperm directly into the egg under the microscope. The actual fusion of the genetic material is a natural process, without any manipulation, and is usually successful. Here also, it is not possible for fertility medicine to force the fusion at any price.

MESA and TESE

Using this method, sperm are taken from the epididymis (MESA: Microsurgical Epididymal Sperm Aspiration) or testicular tissue (TESE: Testicular Sperm Extraction). This is necessary if the quantity or quality of viable sperm in the ejaculate is inadequate or if no sperm whatsoever are found in the ejaculate. Since the tissue can be frozen and used for several treatment sessions, one single procedure is usually sufficient in most cases. After collecting sperm with the MESA or TESE methods, the ICSI procedure is then carried out.

Potential risks and prospects of success

Because ICSI is a relatively new method, it was not clear at first whether there may be an increased risk of deformities in the child. Research findings have shown that the risk of deformity from ICSI is only minimally increased as compared to "normally" produced children, yet in consideration of negative factors on the part of the parents (often older, obesity in the woman, genetic changes) the risk is only about 0.5 percent greater. All other risks from ICSI are identical to those from in vitro fertilisation.

The chances of pregnancy are also roughly the same as with IVF. Since the couples are often younger, then the prospects of success are naturally also better.

What happens in the laboratory?

An important element of ICSI – i.e. the fertilisation of the egg – takes part in the laboratory. To make you feel more comfortable, let us tell you about what goes on in there.

To start, you need to know that not every fertilised egg can actually become a viable embryo. This is perfectly normal and also occurs during "natural" reproduction. Nowadays it is possible to identify viable embryos and return them to their mothers, however. In this respect there is no disadvantage in Germany as compared to treatments abroad.

As already described, the mature eggs are removed through the vagina using ultrasound guidance (follicular puncture) and transferred immediately to the laboratory. The harvested eggs are first incubated in a culture dish (test tube) for about 3 hours, where they have the chance to "recover" and ultimately continue to mature.

While this is happening, the sperm are being prepared. They are cleaned, and then their concentration and motility are analysed. On this basis, only appropriate sperm with high motility and density are selected for use.
Now the eggs are removed from the incubator. To start with, the cells surrounding the egg are removed so that the sperm can penetrate the egg. The eggs are then placed in special culture vessels for microinjection and their maturity level examined. The cleaned sperm are then added and injected into the fertilisable eggs. Once treatment is completed, the injected eggs are placed in a new culture dish with fresh nutrient solution.

The cells are examined under a microscope after 18 to 20 hours for signs of fertilisation. This procedure is known as pronuclear screening. In the egg, a female pronucleus develops from the genetic material of the egg cell, and a male pronucleus develops from the genetic material of the sperm head. If the egg reveals pronuclei, it can be assumed that there has been a fusion of the pronuclei and thus the egg has been fertilised.

During pronuclear screening the cells are separated into fertilised and unfertilised cells, meaning that the eggs to be selected ultimately for transfer will be taken from those with pronuclei. At this point cells are also selected for cryopreservation. Cryopreservation is the method of freezing eggs for later fertilisation.
After a further 24 hours, the initial stages of embryonic division are monitored and documented. Now, the cells are monitored daily until transfer of the embryos. In agreement with the patient, the embryos are returned to her between the second and fifth day of harvesting the eggs. If the embryos are not returned until the fifth day, this is known as blastocyst transfer.