Laser Assisted Zona Thinning Versus the Conventional Mechanical Method for Intracytoplasmic Sperm Injection in ICSI Programs "A Randomized Controlled Trial"

Abstract

Intracytoplasmic sperm injection (ICSI) is a component of infertility treatment often employed when conventional in vitro fertilization is unlikely to be successful. Despite good clinical results with ICSI, the procedure is typically associated with degeneration of a significant percentage (approximately 10%) of the treated oocytes. The cause of this degeneration remains unclear. Speculation that damage caused by oocyte compression during the injection procedure may be responsible has led to the development of a novel technique known as laser-assisted ICSI. This procedure involves drilling a small hole through the zona pellucida with a laser prior to sperm injection. Preliminary studies have suggested that laser-assisted ICSI may dramatically reduce oocyte degeneration rates. The objective of this study was to examine whether the reported benefits of laser-assisted ICSI could be verified on a larger, less-selected group of patients. Oocytes retrieved from 364 patients scheduled for ICSI in specialized reproductive science centre (Dar El Maraa) were randomly divided into equal treatment (LA ICSI) and control groups (C ICSI). Oocytes in the treatment group were inseminated by laser-assisted ICSI, while oocytes in the control group were inseminated by conventional ICSI. Outcome variables (oocyte fertilization and degeneration, embryo cell numbers and fragmentation on days 3 and blastocyst formation rates and biochemical pregnancy rate) were compared between treatment and control groups. We found no evidence that pre-drilling through the zona pellucida prior to insertion of the ICSI needle improves oocyte survival or embryo quality, contrary to the conclusions of two smaller prior studies .Rates of oocyte degeneration and fertilization, cell numbers and fragmentation rates and blastocyst formation were similar regardless of ICSI treatment. Treatment effect on oocyte degeneration rates suggests that even if degeneration rates are lower with laser-assisted compared to conventional ICSI, the reduction is unlikely to be stastically significant as suggested by the earlier studies.