Which men should consider microsurgical epididymal sperm aspiration (MESA)?
Candidates for sperm retrieval from the epididymis include men with congenital and acquired reproductive tract obstruction. One of the most frequent types of congenital obstruction (a male is born with this condition) is bilateral absence of the vas deferens (CBAVD), and this occurs in 1-2% of males with infertility. Acquired vasal obstruction may result from prior failed vasectomy reversal, infection, or trauma (including injury during groin, scrotal, pelvic, bladder neck, or abdominal surgery). First attempts should be made to allow the couple to achieve naturally (if possible) with vasectomy reversal for example. If this is not successful or possible, then the retrieval of sperm directly from the epididymis for use with assisted reproductive technology (ART), specifically IVF/ICSI is the treatment of choice. In the situation of epididymal obstruction, more functionally “able” sperm are found closer to the testis than farther away from the testis (this is opposite of what is found in normal non-obstructed system where the most mature and “able” sperm are found further from the testis toward the vas deferens).
Options for sperm retrieval from the epididymis include percutaneous approach (PESA) which is performed without an operating microscope and routinely in the office setting. This procedure yields small amounts of sperm often contaminated with red blood cells. The cause of obstruction with percutaneous sperm retrieval has not been found to affect offspring outcomes with IVF/ICSI. MESA is the most precise method to collect sperm for IVF/ICSI from the epididysmis. If epididymal sperm aspiration attempts fail, the testis may be considered using testicular sperm aspiration (TESA) done percutaneously, or TESE done with incision. For more information about micro-TESE, click here.
How is MESA different?
The epididymis is carefully and meticulously dissected using the operating microscope. Once a single tubule of the epididymis is incised, fluid is collected using glass pipettes via capillary action and sent for cryopreservation or freshly used for IVF/ICSI.