ICSI treatment overview
ICSI (intracytoplasmic sperm injection) supports the fertilisation procedure outside the body. An individual sperm is transferred inside an egg cell with a thin glass capillary. In this way, fertilisation is achieved even with a reduced sperm quality. The course of an ICSI treatment is arranged like an IVF treatment with the exception of the sperm injection, ICSI technique.
- Very restricted spermiogram parameters e.g.
- Sperm count: under 10 million.
- Sperm progressive motility: under 15 % (WHO).
- Sperm morphology: under 15 % normal shapes (WHO).
- Failed or very limited fertilisation in a conventional IVF cycle.
- Fertilisation with sperm from testicles or epididymes (TESE/MESA) in the event of azoospermia.
- Fertilisation with cryopreserved sperm.
- Fertilisation in the event of retrograde ejaculation.
- Pre-implantation genetic diagnosis (PGD)
Uncovering of the egg cells
In contrast to conventional IVF, the jacket cells must be removed from all egg cells, so that the injection procedure can be performed. Only after its removal can the degree of maturity of the respective egg cell be assessed. The cumulus cells are removed with the enzyme hyaluronidase. Only egg cells in the stage metaphase II are capable of fertilisation and are used for ICSI.
The sperm preparation happens as for IVF. Sometimes, the few available sperm have to be concentrated in the sediment by multiple centrifugation steps.
Preparation of the culture dishes for ICSI
The egg cells and the sperm are prepared for the procedure in microdroplets from the cell culture fluid, which is protected under a layer of oil. The sperm is pipetted into a drop of PVP (polyvinylpyrrolidone) solution. The viscosity of the PVP solution causes the sperm to slow down and allows it to be easily drawn up by the glass pipette.
The ICSI procedure
At the edge of the PVP drop, a sperm is immobilised by the tip of the glass pipette, drawn up and injected into an egg cell. This procedure is repeated with all the egg cells.