Single Human Spermatozoon Freezing Technique For Cryptozoospermia Or Nonobstructive Azoospermia Patients.

Clinical outcome of non-obstructive azoospermia or cryptozoospermia has increased after ICSI when using fresh spermatozoa. When oocyte collection cannot be performed on the same day of the Micro-TESE or in the case of cryptozoospermia, cryopreservation of collected spermatozoa becomes crucial. However, conventional freezing procedures are not appropriate for very low numbers of spermatozoa with poor motility. We performed this study to improve the clinical outcome for single human spermatozoon freezing technique for cryptozoospermia or non-obstructive azoospermia patients. Retrospective analysis of the clinical outcome of 79 ICSI cycles using our novel cryopreservation procedures for single human spermatozoon. This study dealt with 27 men with cryptozoospermia and 20 men with non-obstructive azoospermia from January, 2012 to December, 2014. Moving spermatozoa were carefully aspirated into a pipette one by one and put into a micro-drop of freezing medium (Sucrose-supplemented HTF with SPS) on the vessel (Cryotop®, Kitazato Corporation). About 2μl of freezing medium was put on the tip of the CRYOTOP. 1-10 sperms were aspirated into an injection pipette and inserted into the medium and left in liquid nitrogen vapor for 2 min before being stirred in liquid nitrogen and stored in it. On the day of oocyte retrieval, the vessel was warmed to 37°C and motile sperm were injected into mature oocytes. Zygotes were cultured in a sequential media system (G5 series, Vitrolife) and embryos were transferred into the uterus of the wives. Five healthy babies (5 ongoing) from 47 patients were born following this freezing method. Clinical outcome is listed in the following table.Tabled 1Clinical outcomescryptozoospermiaNon-obstructive azoospermiaNo. of patients2720No. of treatment cycles5227Sperm recovery rate after thawing (%)81.03 (440/543)78.23 (194/248)Motile sperm rate after thawing (%)57.27 (252/440)40.72 (79/194)Fertilization rate (%)33.02 (71/215)37.76 (37/98)Blastocyst rate (%)45.24 (19/42)36.84 (7/19)Clinical pregnancy rate (%)28.57 (8/28)38.46 (5/13)Miscarriage rate (%)25.00 (2/8)20.00 (1/5)No. of ongoing pregnancies23No. of births41 Open table in a new tab This freezing procedure needs a special apparatus (Inverted microscope equipped with a micromanipulator) and requires a high level of technique for gathering and expelling 1-10 spermatozoa correctly and swiftly. So this procedure can only be performed by specialists, precious sperm can easily die with poor technique. Once this procedure is mastered, the clinical outcome of severe male infertility is definitely improved. Especially in the treatment of azoospermia, precious spermatozoa surgically collected from epididymis or testicles can be cryopreserved to avoid repeating a biopsy. This procedure can lessen the patients’ physical, mental and financial burdens.