Findings from a recent study support the use of a deeper incision in microdissection testicular sperm extraction when no sperm-containing tubules are found on the initial wide incision.
Clinicians should also search the contralateral testis when no sperm is discovered initially, according to the study's results, which were presented at the AUA annual meeting in Atlanta.
"A number of the urologists who do this procedure may stop when no sperm is found following initial wide incision," first author Ranjith Ramasamy, MD, a urology resident at Weill Cornell Medical College, New York, told Urology Times. He cited a number of reasons why some surgeons may terminate their exploration of the testis, such as limited experience with the procedure and a belief that when the initial wide incision reveals no sperm, the chances of finding sperm on the more challenging deeper incision or on the contralateral side are small to non-existent.
"This study adds a lot of information to preoperative counseling for both patient and surgeon. The doctor should understand that if he or she does not explore the initial testis thoroughly, there is up to a 35% chance of missing sperm-containing tubules in one of the poles of that testis. And if they do not operate on both testes, there is a 7% chance of missing sperm on the contralateral side," said Dr. Ramasamy, who worked on the study with Peter Schlegel, MD, and colleagues.
Dr. Ramasamy said the study was conducted because up until its completion, there were no data showing which anatomic regions offered the greatest opportunity for sperm recovery, nor were there any data distinguishing patients who might present with sperm on an initial incision from those who might be more likely to require a deeper incision or a contralateral exploration.
The study looked at 900 men undergoing mTESE between 2000 and 2010. Microdissection TESE was initiated in the larger testis and advanced in a stepwise fashion during which tissue samples were removed and analyzed intraoperatively by an embryologist. If no sperm-containing tubules were found, more extensive exploration of the testis to include upper and lower poles was pursued. The pattern was repeated in the contralateral (usually smaller) testis if no sperm was identified during operation on the initial testis.
Of the 900 men with nonobstructive azoospermia in the study, surgeons and embryologists were able to identify sperm in 474 (52.6%) during the first microdissection and retrieve sperm from 245 of these men during the initial wide incision. This latter number is 27.2% of the total cohort. Of the 374 men overall who had successful sperm retrieval, 245 (65%) had sperm identified during the initial wide incision. More extensive dissection found sperm in the remainder of this cohort.
Some 566 men (62.8% of the total) underwent bilateral microdissection and 40 (7%) of these presented with sperm on the contralateral side when no sperm was identified during incision of the initial, larger testis.
Data analysis showed that men with lower preoperative follicle-stimulating hormone levels, larger testes, a history of varicocele, and evidence of hypospermatogenesis on preoperative biopsy had a better chance of presenting with sperm on the initial wide incision. The chances of retrieving sperm in the contralateral testis were slightly higher in men with Klinefelter's syndrome and smaller testes.
These findings demonstrate that a thorough exploration of all regions of both the testes is necessary to offer patients the best chance of successful sperm identification, added Dr. Schlegel.