Cryopreservation of testicular and epididymal sperm: techniques and clinical outcomes of assisted conception

Abstract

The introduction of the technique of intracytoplasmic sperm injection to achieve fertilization, especially using surgically retrieved testicular or epididymal sperm from men with obstructive or non-obstructive azoospermia, has revolutionized the field of assisted reproduction. The techniques for the retrieval of spermatozoa vary from relatively simple percutaneous sperm aspiration to open excision (testicular biopsy) and the more invasive Micro-TESE. The probability of retrieving spermatozoa can be as high as 100% in men with obstructive azoospermia (congenital bilateral absence of the vas deferens, status post-vasectomy). However, in non-obstructive azoospermia, successful sperm retrieval has been reported in 10-100% of cases by various investigators. The surgical retrieval and cryopreservation of sperm, especially in men with non-obstructive azoospermia, to some extent ensures the availability of sperm at the time of intracytoplasmic sperm injection. In addition, this strategy can avoid unnecessary ovarian stimulation in those patients intending to undergo in vitro fertilization-intracytoplasmic sperm injection with freshly retrieved testicular sperm when an absolute absence of sperm in the testis is identified. Several different methods for the cryopreservation of testicular and epididymal sperm are available. The choice of the container or carrier may be an important consideration and should take into account the number or concentration of the sperm in the final preparation. When the number of sperm in a testicular biopsy sample is extremely low (e.g., 1-20 total sperm available), the use of an evacuated zona pellucida to store the cryopreserved sperm has been shown to be an effective approach.

Effect of sperm storage and selection techniques on sperm parameters

“…But it is indeed influenced by the cause of azoospermia, i.e. whether the patient is having OA/NOA [Gangrade 2013;Verheyen et al 2004].…”

“…In patients with non-obstructive azoospermia, sperm retrieval by micro dissection TESE or open biopsy is preferred, and the success rate is estimated to range from 50 to 60% [Gangrade 2013]. The cause for non-obstructive azoospermia also plays a role in determining the success of sperm retrieval.…”

“…But more invasive techniques like micro-TESE or open biopsy are usually needed in patients with non-obstructive azoospermia (NOA). Micro-TESE has the highest sperm retrieval rate compared to open testicular biopsy, multiple fine needle aspiration, and TESA in that order in patients with NOA [Gangrade 2013]. Epididymal sperm are more mature and therefore more motile than testicular sperm and are available for extraction in patients with obstructive azoospermia.…”

The azoospermic male: current knowledge and future perspectives

“…Cryopreservation of testicular sperm is also advisable, especially for men with NOA who often require multiple ICSI attempts to conceive but may not have an adequate number of sperm available for repeated retrieval attempts. These important aspects are discussed by Dr. Gangrade from Orlando, who also presents laboratory protocols for the cryopreservation of epididymal and testicular sperm and discusses the reproductive outcomes of using frozen-thawed gametes for sperm injections (14). …”

A New Strategy and System for the Ex-Vivo Testicle Perfusion and Cryopreservation

“…Testicular cryopreservation can be performed using the slow freezing technique, where a programmable controlled temperature change can be applied, or the Vitrification technique, where the testicular tissue is equilibrated with suitable concentrations of cryoprotectants and directly plunged into liquid nitrogen [3,4].…”