INDICATIONS FOR A SUCCESSFUL ICSI

IVF success depends on a certain number of spermatozoa present in the ejaculated, having good motiliy and morphology. Riedel et al. the minimum andrological requirements for a conventional IVF; 5 x 106/ml concentration, 30% progressive motility and 30% normal morphology. Men having parameters lower than the appointed values had bad prognostics. Nowadays, howevver, the best approach to this kind of male infertility is ICSI: only one living spermatozoon is needed for each M II oocyte (oocyte in the metaphase II cell stage – that means – mature).

Before the ICSI era, various attempts were made to modify and refine conventional IVF in order to enhance pregnancy rates in cases of male infertility. The use of high sperm concentration showed good results in oligospermy and oligoasthenospermy. However, sperm morphology plays an importat role in the success of this type of IVF. Oehninger et al. reported better fertilization and pregnancy rates using high concentration insemination in the cases when spermatozoa were few but morphologically normal. On the other hand, significantly lower implantation and pregnancy rates were observed in patients with severe teratozoospermy. Ombelet et al. indicated that while normal fertilization rates were recovered in cases of moderated teratozoospermy, using high sperm concentration insemination didn’t recover fertilization rates if sperm morphology was below 5% normal form (Kruger’s stict morphology criteria).

More recently, when ICSI was already available, comparative studies have been made between high sperm concentration IVF and ICSI, in the cases of severe teratozoospermy. Higher fertilization rates and better embryo quality were obtained through ICSI when compared to high sperm concentration IVF. A clear tendency for better pregnancy and implantation rates was observed in the ICSI group. Nowadays ICSI clearly surpassed of modified conventional IVF techniques, including high sperm concentration insemination, for the treatment of severe male factor infertility.

ICSI is not strictly indicated for morphological alterations of spermatozoa, but also for low sperm motility and concentration. A summary of four years of ICSI practice indicated that similar results are obtained by ICSI using abnormal semen and conventional IVF using normal semen.

ICSI with ejaculated sperm can be successfully used in patients with fertilization failure after conventional IVF and also in patients who cannot be accepted for these procedure due to na ejaculated having less than 500.000 progressive mobile spermatozoa. High fertilization and pregnancy rates can be obtained when a mobile spermatozoon is injected. The injection of na immobile or dead spermatozoon results in low fertilization rates. Absolute asthenospermy is a sporadic condition except for sperm ultra-structural defects. Therefore, if immobile sperm injection in na initial cycle leads to bad results, subsequent ICSI cycles are justified. Not seldomly do we find mobile spermatozoa in repeated ejaculations.

In case we find only immobile spermatozoa for microinjection, it is important to select the living ones, and this can be achieved by using the hypo-osmotic swelling test (to look for a swelling in the spermatozoon tail): living spermatozoa having na intact cell membrane show a typical swelling when placed inside a hypo-osmotic saline solution. Only these spermatozoa must be selected for the ICSI procedure. Of course the hypo-osmotic test must be preceded by the eosine Y coloration, to exclude complete necrozoospermy. When only dead spermatic cells are present in the ejaculated, using testicular sperm is indicated. Other seminal parameters, like concentration, morphology (except for globozoospermy) and high anti-sperm antibody rates do not influence ICSI success rates. Success with ICSI has been described for patients with acrosome absence.

Any infertility form associated to excretion duct obstruction can be treated by ICSI, by microsurgically removing sperm from the epidydim or testicle. Obstructive azoospermy can result from congenital bilateral absence of vas deferens (CBAVD), vasectomy or vasoepidydimostomy reversion failure. Epidydim sperm is obtained mainly by microsurgery of epidydim and sperm aspiration (MESA), under general anethesia. Other used method is percutaneous epididym sperm aspiration (PESA) preceded by local anesthesia. When immobile sperm is removed from the epidydim, due to na epididymary fibrosis, we can try to remove sperm from the testicles through a biopsy. Two techniques are used to obtain testicular tissue: A biopsy or a thin needle aspiration. Testicular biopsy has also been used in some non obstructive azoospermy cases. In patients having severe testicular deteriorization and germ cell aplasia (Sertoly cell syndrome only), hypospermatogenesis or incomplete maturation, sometimes sperm can be found after multiple biopsies. Sperm removal may not always be successful in all azoospermic patients. However, there is no precise indicator for testicular sperm removal except testicular histopathology. Optimal spermatozoa removed by testicular biopsy can be obtained by a delicate tissue wash. Very frequently can we find living spermatozoa after enzymatic treatment of testicular samples, for red cell removal.

Cryopreservation of supranumerary spermatozoa removed from the epidydim or testicle has na important function, because frozen or unfrozen sperm microinjection may be used, avoiding surgery in future ICSI cycles. Successful ICSI using frozen epidydimal sperm has been described. This also holds true for pregnancy resulting therefrom. Testicular sperm cryopreservation is less frequently used and more difficult, because only a limited number of spermatozoa is present for good results. Cohen et al. have recently described a cryopreservation method with reduced spermatozoon number inside the empty oocyte zona pellucida; although adapting this method for testicular biopsy may take excessive time.

It must be added that ICSI method may not be used in approximately 3% of the cycles. This may result from the fact that the cumulus-corona complex or Metaphase II oocytes are not available, or there couldn’t be found any sperm in testicular biopsies in patients with non obstructive azoospermy.

Due to excellent fertilization rates and good embryo development, ICSI has been indicated for practically all infertility cases, even in the absence of a male infertility factor.

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