Robotic intracytoplasmic sperm injection (RICSI)

International Journal of Reproductive BioMedicine

Volume 9 - Number Suppl.2

Article Type: Original Article
Abstract:

Before the introduction of micromanipulation, the majority of cases of severe male infertility were generally not treatable. In-vitro fertilization (IVF) cycles were cancelled in about one-third of these cases due to failed fertilization. The introduction of micromanipulation techniques such as zona drilling, partial zona dissection, and subzonal insemination reduced the incidence of failed fertilization and salvaged many IVF cycles. However, there was little improvement on fertilization and pregnancy outcome because these procedures required a relatively high number of progressive motile sperm, which in turn frequently resulted in a high incidence of polyspermy in inseminated eggs. To overcome these limitations, microinjection of a single sperm into the ooplasm (intracytoplasmic sperm injection, ICSI) was developed. ICSI resulted in a dramatic improvement in fertilization rates and revolutionized the treatment of infertile couples with severe male factor. ICSI however, is a labor intensive procedure where a highly trained embryologist uses a hydraulic micromanipulation system to pick up a single sperm and inject it under high power magnification into a human oocyte in order to fertilize the oocyte. This process is technically challenging, and consequently there is a long learning curve of up to 6 months for a trained embryologist to be able to become skillful with this procedure. We developed a robotic ICSI system featuring fast oocyte positioning, automated sperm tracking and immobilization, and adaptive oocyte injection with minimal human involvement. A cell holding device is developed to hold many oocytes into a regular pattern. A sperm tail tracking algorithm robust to the low-contrast appearance and the nonlinear fast movement of the sperm tail is developed. In addition a computer vision algorithm is developed to recognize oocyte structures for adapting injection parameters. The robotic system is able to inject 6-9 oocytes at a time markedly reducing the time the oocytes are out of the incubator and exposed to cooling or changes in PH of the culture medium that can be detrimental to embryo development. Finally, the system performs the injection the same way for each oocyte resulting in more uniform results and fewer damaged oocytes. Different from conventional ICSI setups that consist of two micromanipulators and use both a holding micropipette and an injection micropipette, our system contains only one micromanipulator and uses a single injection micropipette for the complete ICSI task.