Extended Sperm Search and Microfreeze (ESSM) is a revolutionary procedure that can detect sperm in previously diagnosed azoospermic men. The procedure is non-invasive, painless, and has found sperm in up to 44% of cases. Here’s a break down of the process and equipment we use in our lab to perform this procedure.
THE INVERTED MICROSCOPE
A standard upright microscope used for semen analysis has a light source below the stage and objectives- the magnifying lenses- above the stage. This is a good setup for looking at slides. An inverted, or live tissue microscope, has the light source above and the objectives beneath the stage. This allows us to look into a petri dish with live cells without lowering the objectives into the dish. It also leaves room for the installation of a micromanipulator.
The micromanipulator is made up of 3 parts: the manipulator, the injector and the pipette. It allows for the handling of cells too small to be manipulated with a manual pipette. The micropipette used for sperm measures 5-10 micrometers in diameter. For comparison, a human hair is between 17-180 micrometers. The average width of a sperm head is 3 micrometers. The tip of the micropipette can’t even be seen without the microscope! The micropipette is connected to the manipulator, which allows for movement up, down, left, right in the petri dish. It is also connected to the injector, essentially a syringe that can aspirate and expel small cells. This setup is used to isolate single sperm for cryopreservation.
THE SPERM VITRICATION DEVICE
The SpermVD is the device used to cryopreserve small quantities of sperm. This device is roughly the size of your fingertip, from tip to first knuckle. A droplet of cryomedia is placed on the surface of each ring, and 3-5 sperm can be placed in each droplet with a micromanipulator. The device is then placed in a standard cryovial and plunged directly into liquid nitrogen. Because of the tiny volume of the droplet, it freezes instantaneously. This process has been shown to have better survival than conventional slow freezing.