Many of the men seen in our practice for male infertility are azoospermic. This means they have no measurable amount of sperm in their ejaculate. This is a significant issue for these men wanting to have a biological child. Approximately half of these men have Obstructive Azoospermia (OA). Their testes produce enough sperm, but a blockage exists in either the vas deferens or the epididymal tubules that prevents the transport of sperm from the testes to the tip of the penis. Sometimes the vas deferens and epididymal tubules are missing. The remaining half of our azoospermic patients have Non-Obstructive Azoospermia (NOA). Their vas deferens and tubules are clear and open, but the ability of their testes to produce sperm is impaired.
Medical interventions exist that enable many men with azoospermia to father their own biological children. Blockages can be surgically removed, and sperm production can sometimes be improved with pharmacological treatments. However for most men with NOA and many with OA, the only avenue available for achieving a pregnancy with a partner is to have sperm surgically retrieved from the testes and then used in an assisted reproductive technology (ART) treatment protocol involving invitrofertilization (IVF) or intracytoplasmic sperm injection (ICSI).
In conventional testicular sperm retrieval (TESE), a small incision is made in the scrotum exposing the testes. An incision is then made in one of the testes, through the tunica albuginea (protective outer covering of the testis) to expose its parenchymal (working) tissue. Special care is taken to avoid blood vessels. Pressure is applied along the incision until tissue containing seminiferous tubules protrudes through the incision site. This tissue is surgically removed and set aside for cryopreservation and/or immediate use in IVF/ICSI. The procedure is then repeated on the other testis.
Seminiferous tubules are the site of spermatogenesis (sperm production). However, spermatogenesis is not uniform throughout the testes, and so at any given time some seminiferous tubules will have much higher concentrations of sperm than others. It is not possible to evaluate the degree of spermatogenesis in seminiferous tubules with the naked eye. So a surgeon has no way of visually assessing the tissue he intends to extract during a TESE for the presence of sperm. For men with OA this conundrum is usually not problematic. They produce plenty of sperm, so chances are quite good that testis tissue retrieved by conventional TESE will contain sufficient sperm for IVF/ICSI. This is not the case however for men with NOA. Because their ability to produce sperm is impaired, the sperm concentration in their seminiferous tubules can range from adequate in some tubules to non-existent in others. As a result, they run the very real risk of having testis tissue retrieved by conventional TESE that is devoid of sperm and therefore unsuitable for IVF/ICSI despite having sufficient sperm production in another portion of the testicle.
When sperm are not found in conventional TESEs, fertility specialists often counsel patients that no viable option exists to achieve a pregnancy with a partner. Patients are encouraged to start looking at sperm donors. This is outdated advice given by professionals who are unfamiliar with microdissection testicular sperm extraction (micro TESE).
A micro TESE is a very different, far more complex type of surgical sperm retrieval compared to a conventional TESE. It is performed by an experienced urologic surgeon, who is an expert in the use of an operating microscope. The surgeon is assisted by a team of andrologists (specialists in the laboratory techniques required to identify and extract sperm from testicular tissue). An incision is made in the scrotum exposing the testes. Thirty or more microscopic specimens containing seminiferous tubules are taken from several sites on each testis. Individual seminiferous tubules in each of these samples are examined in the operating room by the andrologist to determine the presence of sperm. Seminiferous tubules containing sperm are usually plumper, whiter, and more opaque than tubules with inadequate concentrations. The surgeon is thus able to extract only tissue with the best potential to contain sperm, which is key to the success of the procedure. Once tissue has been extracted, the andrologist will further examine it to assess sperm quality (concentration, maturation, morphology). The andrologist will also prepare the tissue for immediate use or cryopreservation. Using this approach, the operating team can focus on sites that appear to yield the best sperm concentration and quality, ensuring that a sufficient quantity of the most “promising” tissue is extracted. A micro TESE typically takes several hours from first incision to last suture. A conventional TESE is usually completed in under an hour.
Micro TESE offers several advantages over conventional TESE. Studies show that for men with NOA, sperm retrieval rates (SRR) by micro TESE are significantly higher than conventional TESE. “Sperm was recovered from those with hypospermatogenesis in 84% and 92.9% by conventional and microdissection TESE, respectively. In the case of maturation arrest, SRR was 27.3% and 36.4% respectively. In cases of Sertoli-cell-only syndrome (SCOS) the SRR was 6.2% and 26.9% respectively.”1 Use of an operating microscope minimizes the amount of tissue that is removed, as many microscopic specimens are taken rather than larger biopsies. Use of an operating microscope also enables the surgeon to avoid disrupting blood vessels, decreasing the likelihood of damaging vascularized areas of the testes. This minimizes trauma and the resulting loss of functionality, such as a decline in testosterone production. Better retrieval rates enable andrologists to cryopreserve testicular tissue for later use. Using cryopreserved sperm eliminates the need for synchronizing egg and sperm retrievals. It also eliminates the trauma and potential tissue damage caused by multiple sperm retrievals.
There has been some debate over use of fresh versus thawed sperm for ICSI. Many fertility specialists believed better outcomes are achieved with fresh sperm, as cryopreservation damages both cell and acrosome membranes and increases damage caused by sperm oxidative stress. However several recent studies refute this assumption. A recent review of data from 224 studies focusing on men with NOA revealed no difference in fertilization and pregnancy rates with fresh versus cryopreserved sperm used for ICSI.
Microdissection testicular sperm retrieval is offering new hope to men with NOA. However, I am ending this blog on a cautionary note. This is not a procedure that can be done many surgeons. It requires a highly skilled urologic surgeon who has extensive experience using an operating microscope and doing testicular sperm retrievals. The surgeon is key to the success of this procedure, so choose wisely.
Ghalayini IF, A-Ghazo M, et al. Clinical Comparison of Conventional Testicular Sperm Extraction and Microdissection Techniques for Non-Obstructive Azoopsermia. J Clin Med Res. 2011; 3(3): 124-131.
Ravissini PC, Azevedo M, et al. Secuess rate in ICSI treatment of men with non-obstructive azoospermia (NOA): a comparative study between TESE (testicular sperm extraction) and microdissection-TESE. Fertil Steril. 2008; 90: S382-S383.
Ohlander S, Hotaling J, et al. Impact of fresh versus cryopreserved testicular sperm upon intracytoplasmic sperm injection pregnancy outcomes in men with azoospermia due to spermatogenic dysfunction: a meta-analysis. Fertil Steril. 2014; 101(2): 344-349.
Ishikawa T, Nose R, et al. Learning curves of microdissection testicular sperm extraction for nonobstructive azoospermia. Fertil Steril 2010; 94(3): 1008-1011.0