Testicular sperm extraction: TESE is a procedure to collect sperm directly from testes. It's done if there are no sperm found in semen, the milky white substance where sperm live. This procedure is carried out because:
The testes aren’t making enough sperm in your semen.
A blockage is preventing the sperm from passing out of the penis.
The study was done by M. E. Bakircioglu and team to evaluate the results of microdissection TESE in patients with non-obstructive azoospermia and cryptozoospermia for intracytoplasmic sperm injection (ICSI). Two hundred seven azoospermic and 33 cryptozoospermic patients were attempted 245 cycles for ICSI treatment and underwent microdissection TESE for sperm recovery in between June 2002 - December 2003.

All patients completed an evaluation including volume estimation by orchidometer, karyotype analysis, Y chromosome microdeletions and serum levels determination of FSH and Total Testosterone. On the day of oocyte pick-up semen analyses were repeated and testicular biopsies were collected for histological analysis at the operation.
Testicular sperm was successfully retrieved 136 out of 245 (55,5%) ICSI cycles with microdissection TESE. Within the cryptozoospermic subgroup, 28 out of 33 (85%) TESE attempts were successful for sperm recovery while in the azoospermic group 108 out of 212 (51%) TESE attempts were successful. Karyotype analysis was showed 36 non-mosaic and 3 mosaic Klinefelter’s syndrome. Six azfc microdeletion was diagnosed for Y microdeletion. At the time of the operation, testicular biopsies were taken for histological evaluation in 148 cases. Statistical analysis did not find age, testicular volume, FSH and Total Testosterone levels to have predictive value for the presence of sperm.
For non-obstructive azoospermic patients microdissection TESE is an effective sperm retrieval procedure. Although testicular sperm retrieval rate is high in cryptozoospermic patients, repeated semen analyses and sperm collection for cryopreservation should considered before ICSI treatment. Non-obstructive azoospermic patients should recommend both karyotype analysis and Y chromosome microdeletions.
Source: M. E. Bakircioglu, S. Kahraman, S. Sertyel, N; FERTILITY & STERILITY
doi:10.1016/j.fertnstert.2004.07.221