What is microdissection testicular sperm extraction (micro-TESE), and why choose to have it?

Microdissection testicular sperm extraction (micro-TESE) is the microsurgical technique utilized to search methodically through the seminiferous tubules of each testis using the surgical microscope to identify and obtain sperm (if present) from the testes of men without sperm in the ejaculate (called non-obstructive azoospermia).  If sperm are identified (as few as just several sperm could be adequate), these may be used for fertilization using in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).  Micro-TESE is the optimal technique for sperm retrieval which results in the least scarring to the testicle is microdissection testicular sperm extraction (micro-TESE).  

Who are candidates for sperm extraction with micro-TESE?

For men who have no sperm in the ejaculate (non-obstructive azoospermia), there are several sperm retrieval techniques that can be used all of which involve obtaining sperm either with a small scrotal and testicular incision (testicular sperm extraction, TESE) or needle placed into the testicle (testicular sperm aspiration, TESA; Fine Needle Aspiration, FNA mapping).  As described, micro-TESE produces optimal outcomes with least scarring of the testis.

What are the predictive factors for micro-TESE?

Men who are older or have smaller testes, higher FSH, or higher BMI levels are do not have worse sperm retrieval rates with microTESE.  Micro-TESE is successful post-chemotherapy as well with varying rates depending on the type of chemotherapy regimen.  However, male BMI is a predictor of successful pregnancy.

Do you need many sperm for ICSI?

With the use of IVF and ICSI since the 1990′s, millions of motile sperm are no longer required to fertilize an egg.  The procedure can be performed with the best sperm available, but can be completed successfully with a single non-motile sperm.  The embryologist selects a specific sperm and the sperm is placed in a small hollow needle.  This needle is used to pierce the outer layer of the egg, and the sperm is injected into the egg cytoplasm (center).  Following this, the egg (now with sperm inside) is placed in the incubator and then checked for signs of fertilization.

What is ICSI and what happens once sperm meets egg?

ICSI is an in vitro fertilization procedure during which a single sperm is directly injected into the egg which have been obtained from the female partner.  Prior to the use of ICSI in the 1990′s, the only option for men with poor semen parameters and male factor infertility was donor sperm or adoption.

Following ICSI, successful fertilization is required for embryos to form. Fertilization is a complicated process during which one sperm unites with an activated egg (oocyte).  The most important steps for successful fertilization include sperm capacitation, sperm binding to the egg’s outer coating (zone pellucida), and fusion with the egg.  After the sperm enters the egg’s cytoplasm, a reaction occurs (the cortical reaction), preventing more sperm from fertilizing the same egg. The oocyte then completes its second (meiotic) division producing the final egg (haploid ovum) and releasing a polar body. The sperm nucleus then fuses with the ovum with fusion of the sperm and egg’s genetic material.  There are many possible reasons for fertilization to be unsuccessful which will be considered in the management by your physicians.

We are pleased to discuss additional aspects of the micro-TESE procedure. Please contact us for additional information.

Matthew Wosnitzer, M.D.