If too few or too immobile sperm cells are present in the sperm test ICSI (Intra cytoplasmatic Sperm Injection) is the method to use for fertilisation. Even if some male sperm cells may only be retrieved by aspiration from the testicular tubules from the testis - a method known as TESA.
At ICSI, the oocytes first are liberated from the surrounding so called granulosa cells. These naked oocytes may be evaluated in details by high power microscopy. The mature egg cells may be used for ICSI.
By ICSI one single anatomically normally looking and motile spermatozoa is captured by a tiny pipette (diameter 5 my). The interior of the spermatozoa is reached by introducing a small break of the tail, which activates the spermatozoa prior to fertilisation. The activated spermatozoa is introduced to the oocytes away from the nuclear area of the egg cells.
After this method the scheme for controlling the succeeding steps is similar to those described under the section - IVF.