Intracytoplasmic sperm injection: laboratory set-up and injection procedure.

Intracytoplasmic sperm injection (ICSI) as treatment for male-factor infertility has been introduced worldwide in the past few years in many laboratories using assisted reproduction techniques. Some changes in the existing set-up are necessary before implementing this procedure. The equipment can be divided into two groups: that required for preparation of the microtools and that required for the microinjection procedure itself. A pipette puller, grinder and microforge are necessary for preparation of the microtools. The correct settings and use of these instruments are of crucial importance in preparing a good needle, which in turn is crucial to the injection procedure itself. The microscope has to be equipped with a heated stage, correct optics and manipulators and injectors. The correct settings and use of this equipment also influence the injection procedure and may influence the success rate. Retrospective analysis of the evolution of ICSI in our centre clearly shows a marked improvement following the introduction of some modifications into the procedure. These modifications were (i) reducing the concentration of hyaluronidase used for cumulus and corona radiata removal, (ii) selecting a motile spermatozoon that was immobilized prior to the injection and (iii) aspiration of cytoplasm to ensure rupture of the oocyte membrane. The injection procedure itself can also be influenced by oocyte characteristics. It has been reported that the reaction of the oocyte to the penetration by the pipette has an influence on the success rate. The ICSI procedure has about the same success rate as IVF in cases of non-male infertility. However, work can still be done to improve the success rate of this procedure.