Laser in assisted reproduction and genetics.

Journal of Assisted Reproduction and Genetics, Vol. 9, No. 4, 1992 LASER Laser in Assisted Reproduction and Genetics 1 Laser beams were introduced to the field of as- sisted reproduction in the late seventies and early eighties, when the carbon dioxide laser (operating at a 10,600 nm wavelength) was coupled to oper- ative microscopes (1) and laparoscopes (2,3) for reconstructive pelvic surgery. Later, specially de- signed rigid (4) and flexible (5) delivery systems for this laser, as well as other lasers [argon 540 nm (6); Nd:YAG 1064 nm (7); and frequency doubled YAG 532 nm (8)] were developed and clinically evalu- ated. Numerous publications described conflicting data on the potential superiority of each of these laser wavelengths for specific applications and compared them to conventional operating acces- sories (9,10). Different criteria for patient selection as well as personal skill and bias could affect the analysis of these data. There is no doubt that for certain applications, laser light may selectively in- teract with tissue (i.e., pigmented endometriotic im- plants), cause minimal effect to surrounding tissue, and thus offer significant advantages over other techniques. Another important characteristic of the lasers in endoscopic surgery (mainly the CO2 laser) is the what you see is what you get effect (WYSIWYG). However, most indications can be handled without the use of the laser (10). Some surgeons claim that the laser is cumbersome for endoscopic application. The experienced laser endoscopist can take ad- vantage of the laser's special effects if properly handled, i.e., alternate quickly between a small- spot size cutting beam and a superficial vaporiza- tion using a large spot, combining maneuvers of cutting and blood vessel sealing at the same time, and using contact fibers with different tip profiles to obtain different effects (11). Controversies on the place of the laser in operative laparoscopy are ex- pected, and one has to view its existence as an additional tool to other accessories. In experienced hands it can offer significant advantages in prop- erly selected indications. Future developments in delivery systems, imaging technologies, and pho- todynamic therapy might offer significant advan- tages for the use of lasers in minimally invasive sur- gery. Progress in the treatment of infertility, in which oocytes were fertilized outside the human body, has contributed significantly to the understanding of reproductive mechanisms. The first decade of this new era was dedicated mainly to trial-and- error studies, followed by controlled trials and the definition of guidelines for proper patient selection. The term in vitro fertilization (IVF) was broadened to assisted reproductive technologies (ART), and the need for more accurate equipment became self- evident. The main goals of ART today are (a) im- proving the implantation rate following embryo transfer, (b) improving the fertilization rate in the presence of poor sperm quality, and (c) serving as a platform for molecular genetic studies at the pre- embryo stage. Extensive basic research and clini- cal trials with micromanipulation techniques are be- ing developed to achieve these goals. Procedures such as subzonal sperm insemination (12), various methods of zona opening (13,14), assisted hatch- ing (15), and preembryo biopsy are being perfected. The high precision of laser beams and the pos- sibility of reducing the beam spot size from 500- 1000 i~m [used for tissue microsurgery (16)] to 0.5-3 #m (needed for cell and subcellular or- ganelle microsurgery) stimulated its adaptation for ART. Using a laser-generated optical trap, sperm could be manipulated in two (17,18) and three (19) dimensions. Initially, a Nd:YAG laser was used, at powers as low as 10-40 mW. Recent experiments in our laboratories revealed that similar effects are The opinions presented in this column are those of its author(s) and do not necessarily reflect those of the journal and its editors, publisher, and advertisers. 1 With this article, we are welcoming Yona Tadir, M.D., to the Editorial Board of this journal. Dr. Tadir, who is internationally known as a pioneer of laser applications in reproductive med- icine, has agreed to assure the constant update of our readers in this very rapidly developing field. N.G. © 1992 Plenum Publishing Corporation