Complete failure of fertilization is very rare in ICSI. ICSI gives hope in cases of severe oligospermia and even azoospermia. It bypasses the ovolemma and zona pellucida of eggs. In azoospermia spermatids are obtained from epididymus ( MESA , PESA) or testes (TESE). In MESA or TESE, elongated spermatid is better. Results from mechanical immobilized sperms are better. It also helped to understand better some key steps of fertilization process.
Unfortunately there were, and are, no effective treatments to increase sperm quantity & quality unless there is a specific, responsive cause such as a blockage or severe hormone imbalance.
Higher fertilization and pregnancy rates regardless of sperm characteristics make ICSI the best procedure yet to treat male factor infertility. It is independent of basic sperm factors, i.e. concentration, morphology and motility. ICSI is a laboratory procedure adopted when: