Sperm Retrieval - TESE or MESA
> Definition > MESA or Microepididymal Sperm Aspiration
> TESE or Testicular Sperm Extraction > ICSI or Intracytoplasmic Sperm Injection
This technique is used for men with no sperm in their semen because of a blockage or an absence of the vas deferens (the tube which leads from the testis).
There is a group of men who have no sperm in their semen because of a blockage or an absence of the vas deferens. The vas deferens is a tube, which leads from the testis towards the penis; sperm must travel down this tube to leave the body. Such men may be producing sperm in large numbers, but because there is a blockage or absence of the vas deferens none will be seen in the semen. This is similar to a man who has had a vasectomy.
In these cases sperm can be obtained from the epididymis, which is an organ which is located on top of the testis where sperm collect and mature. If the epididymis itself is blocked or absent sperm can be extracted from the testicles.
Assisted Reproductive Technologies (ART) are techniques which bring the sperm closer to the egg.
In many cases, a treatable cause of male infertility has not been identified or treatment has not resulted in pregnancy. ART or assisted reproductive technologies may be sued to bring and place the sperm closer to the egg with the hope that this will achieve a pregnancy. Procedures that may be performed include:
MESA OR MICROEPIDIDYMAL SPERM ASPIRATION
Although we routinely perform both first time and repeat vasectomy reversals, we are often approached regarding the possibility of combining sperm retrieval procedures with in-vitro fertilization as an alternative to vasectomy reversal or in cases of non-correctable duct obstruction such as congenital absence of the vas deferens.MESA or microsurgical epididymal sperm aspiration has perhaps been the procedure most commonly performed in men with vasal obstruction. A scrotal skin incision is made, and the testis and epididymis are exposed. Using an operating microscope, a single epididymal tubule is located and sperm aspirated. The procedure may be performed with a general or local anesthetic with intravenous sedation. MESA is also the procedure of choice because of the ability to retrieve a large number of sperm that may be cryopreserved (frozen) and used in future cycles. Many men may be candidates for a reconstructive vasoepid dymostomy at the same time of sperm harvest, thus increasing the chances of having sperm appear in the ejaculate. Recovery time form the operative procedure is only a few days and complications are rare. Dr. Elizabeth Houser has had several successful pregnancies after reconstruction.
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TESE OR TESTICULAR SPERM EXTRACTION
In approximately 7% of men undergoing microsurgical epididymal sperm aspiration (MESA) sperm retrieval is not possible. Recent work has shown that whole, motile sperm can be obtained form the testicle itself. Critical to the success of TESE is determination that the testis is making mature sperm. If mature sperm with complete tails are present on this examination TESE is feasible. The urologist previously used testis biopsy for diagnostic purposes only. Now sperm harvesting has become an important addition to the indications for this procedure. Current practice is to perform a small diagnostic testis biopsy prior to proceeding with testicular sperm extraction (TESE). Because of the low number of sperm obtained with TESE, an extracted sperm needs to be combined with the wife's egg which has been retrieved through an IVF (in vitro fertilization) cycle.
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TESE (testicular sperm extraction)
A fine needle is inserted into the testis and samples of tissue are obtained by gentle suction and examined under the microscope. If sperm are not found, a small tissue sample (testicular biopsy) is taken through a small incision in the scrotum and testis, sperm can then be extracted from the tissue. Finding sperm in the testicular tissue can be a laborious process.
Surgically retrieved sperm are immature and incapable of fertilization by conventional means. Fertilization is achieved using Intracytoplasmic Sperm Injection (ICSI), this involve injecting a selected sperm into the cytoplasm of a mature egg.
After the operation, You may feel discomfort, bruising and tenderness of the scrotum for 24-48 hours. There is a small risk of infection and bleeding after the procedure. A firm scrotal support is recommended until the discomfort subsides. The long-term effects of repeated testicular biopsy are poorly understood.
Any spare sperm or testicular tissues may be frozen for later use, thus avoiding a repeat of surgical sperm retrieval procedure.
In case no sperm are found, the couple may either decide to cancel the egg collection and abandon treatment altogether, or proceed with the egg collection and inseminate the eggs with donor sperm if this has been discussed and agreed before hand as a 'backup'.
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ICSI OR INTRACYTOPLASMIC SPERM INJECTION
This is a micromunipulative technique for injecting a single sperm into an egg. This has allowed for pregnancy in specific cases of infertility where in the past success was very unlikely. ICSI has revolutionized the treatment of severe and otherwise untreatable male factor infertility. Success rate with ICSI varies with each IVF center and the skill of the technologist. If ICSI is an acceptable option to the couple, adequate counseling regarding the potential for genetic defects should be provided.
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The early stages of ICSI are the same as for standard IVF. The woman takes fertility drugs to stimulate her ovaries with the aim to grow several mature follicles. The eggs are usually collected by vaginal ultrasound scan into a specially prepared culture medium. Once the eggs are collected, they are examined under the microscope to assess their quality. The eggs are then placed in the incubator for a period of time usually between 3-6 hours. Thereafter the eggs are removed from the incubator and the cells that surround the egg are stripped off to assess the maturity of the egg, because ICSI can only be performed on mature eggs. Immature eggs can be kept in the culture medium and injected the following day if they show signs of maturation.
Sperm collection from ejaculate or aspirate from the epididymis (MESA) or testis (TESA or TESE) is prepared using special cultured medium. Sperm preparation may also be obtained from frozen semen sample or testicular tissues.
Once the eggs have been selected, a chosen sperm is rendered immotile, then sucked into the tip of a very fine glass needle and injected directly into the egg. The egg is held in place by gentle suction on the opposite side using a holding pipette. This is a very delicate procedure and involves using a micromanipulator. This process is repeated for each egg. The elastic nature of the egg membrane means that the tiny hole made by the needle closes very quickly. About 5% of the injected eggs may be damage by the procedure.
The eggs are examined the next morning for signs of fertilization. The developing embryos are allowed to grow and cleave (divide) for a further 24-48 hours. Not all fertilized eggs will divide and some embryos may arrest (stop growing) at an early stage of development. Any excess embryos of suitable quality are then frozen for later transfer.
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