Tissue digestion in lab finds sperm post-microdissection testicular sperm extraction

October 1, 2011

Analyses of data from a large series of men undergoing microdissection testicular sperm extraction (mTESE) showed that among patients who had no sperm found in the OR, 7% had sperm identified following tissue digestion and extensive searching in the laboratory.

The study, which was presented at the AUA annual meeting in Washington and subsequently published in Fertility and Sterility (2011; 96:299-302), included 1,054 men who underwent mTESE performed by senior author Peter Schlegel, MD, professor and chairman of urology at Weill-Cornell Medical College.

"These data offer valuable information for counseling couples in the immediate postoperative period," he added.

The mTESE protocol involves mechanical mincing of the testicular samples in the OR with several passes through a 24-gauge microangiocatheter followed by intraoperative examination by an embryologist using phase contrast microscopy (200X magnification). If no sperm are seen, the extracted tissue sample is further processed with 1% collagenase digestion for 1 hour at 37°C and then re-analyzed using a series of microdroplets examined with Nomarski optics.

The study also investigated whether there are any preoperative or intraoperative parameters that predict the chance of finding sperm in the lab when no sperm are found in the OR. Men who had sperm discovered in the lab were compared with their counterparts who had no sperm discovered with respect to age, testicular volume, varicocele, serum follicle-stimulating hormone, Klinefelter syndrome, cryptochordism, and testicular histology features (Sertoli cell only, maturation arrest, hypospermatogenesis).

Germ cells predictor of finding sperm

In the multivariable analysis, identification of germ cells in the OR by an embryologist was the only factor that independently predicted finding sperm in the lab; the finding of germ cells increased the likelihood of finding sperm in the lab by nearly fivefold.

"Further stratification by baseline FSH showed that men with FSH >20 U/L and germ cells found in the OR had the best chance of finding sperm in the lab (about 25%)," Dr. Ramasamy reported.