Microsurgical Sperm Retrieval (Micro-TESE) – Standard of Care for Non-Obstructive Azoospermia
Male factor infertility is present in more than half of couples with delayed conception, making it the leading cause of subfertility in North America. Between 5 and 10% of these men have a complete lack of sperm due to reduced production (non-obstructive azoospermia). Testicular biopsy reveals that these men have Sertoli cell-only pattern, maturation arrest, or hypospermatogenesis. Until recently, these men with primary testicular failure were considered “sterile”, and donor sperm insemination or adoption recommended as the only means of having a family. Several observations have changed the approach to this condition. Direct evaluation of testis biopsy specimens often demonstrates sperm in men with non-obstructive azoospermia, but not at high enough levels to yield sperm in the ejaculate. It was previously assumed that sperm must traverse the male reproductive tract before acquiring the ability to fertilize an egg. These sperm do have severely impaired motility and function, and are ineffective when used for intrauterine insemination (IUI) or standard in vitro fertilization (IVF) culture. Using the procedure called intracytoplasmic sperm injection (ICSI), eggs can now be fertilized with these sperm by physically injecting them into the cytoplasm of the egg (ooplasm). ICSI was first performed in 1990 and has virtually cured male factor infertility world-wide. The vast majority of infertile men can eventually father a child using this technique.
With advances in sperm retrieval techniques, sperm can be found in nearly half of men with non-obstructive azoospermia. Microsurgical testicular sperm extraction (Micro-TESE) is a procedure that allows for the precise removal of tiny volumes of testicular tissue is areas of active sperm production using a microscope, improving sperm yield compared to traditional biopsy techniques. Seminiferous tubules (structures where sperm is produced and transported) containing sperm can often be identified under an operating microscope after opening the testis. This approach has a number of advantages over other sperm retrieval techniques. It maximizes the yield of spermatozoa while minimizing the amount of testicular tissue required and vascular injury created, by making identification blood vessels easier. Sperm harvested from these patients is very difficult to cryopreserve due to a combination of the limited numbers and quality, so optimal pregnancy rates are achieved using the sperm fresh.
Using fresh sperm requires synchronizing the Micro-TESE procedure with retrieval of the female partner’s eggs. The medical team at The New York Presbyterian Hospital-Weill Medical College of Cornell University, under the direction Dr. Peter Schlegel pioneered the technique and is the major referral centre in the U.S. for difficult azoospermia cases. In 2007, Dr. Schlegel performed the first Micro-TESE procedure at PCRM as a visiting professor. With a fully functional operating theatre on-site, and embryologists with years of TESE experience in an adjoining full-equipped IVF laboratory, PCRM has proven to be well suited for Micro-TESE. Since that day we have provided a consistent volume of Micro-TESE for these severe cases with a cumulative pregnancy rate of 78%.
We are the only centre in Canada capable of fresh Micro-TESE; this urological procedure is done through our Sub-specialty urology staff, Drs. Victor Chow, and Kenneth Poon. Many centres perform this outside the clinic, and freeze sperm, however, the ability to procure fresh sperm is highly linked to better pregnancy outcomes. Many other fertility centres in Canada refer patients to PCRM for this procedure.