Answer from: Andrew Thomson, FRCPath
TESE is where you are essentially a testicular biopsy where you cut with a scalpel cut directly into the testicles and remove tissue directly from it. Sometimes it’s done with the use of a microscope so they look for what look to be the best tubules in the testicles. PESA is where you put the needle directly into the epididymis and aspirate and the epididymis is where the sperm is stored normally, so if you produce sperm it’s just an access issue you’ll in most cases get sperm directly that way.
Answer from: Tomas Frgala, PhD
The TESE method – the testicular sperm extraction where actually small biopsies of the tissue, small pieces of the tissue from the testes are collected during the surgery and then they’re worked with in the lab to provide actually the sperm cells. These sperm cells are looked for and extracted from this tissue so sometimes even in a situation where the ejaculate itself carries no sperm cells, we are able to get these directly from the testes and fertilize the eggs of the partner of the woman with the man’s sperm cells successfully.
How is a TESE done?
Increasing awareness of fertility troubles being proportionally caused by male factors led towards improving techniques involving semen preparation for the IVF. There are no longer simple IUI treatments available for male factor but procedures like TESA, TESE, micro-TESE to name a few.