Research On The Mechanism And System Of Selective Abortion Surgery With Pulsed Laser

The prevalence of multifetal pregnancy has recently shown an exponential increase due to the wide use of ovarian stimulation fertility drugs and assisted reproductive technology. Multifetal pregnancy, especially with more than two embryos, has a high risk of obstetric and perinatal morbidity and mortality. The health status of both the gravida and the embryos should be monitored when more than three intrauterine embryos are present. Multifetal pregnancy reduction is introduced to avoid the increased incidence of abortion and premature labor associated with multiple gestations. However, the main techniques of pregnancy reduction surgery currently in use have many disadvantages, including long operative time, complicated surgeries, and risks of vessel perforation.In this study, we present a novel reduction method that used a1064-nm pulsed laser to overcome these disadvantages of traditional surgery. Laser surgery allows the noncontact cutting and removal of a wide variety of living tissues. Compared to the conventional pregnancy reduction surgery, laser technique can shorten the duration of surgery, avoid the deviation caused by quickening, improve the accuracy of the operation, minimize the surgical trauma, and reduce the patient’s recovery time.Firstly, based on the mechanism of the interaction between laser with biological tissue and optical characteristics of laser act on the biological tissue, the theoretical analysis of the laser-assisted reduction surgery (LARS) and the basic principle of optical breakdown effect which occurred in LARS have been earried out. These theories lay a foundation for the subsequent simulation calculation and experimental study. Secondly, the theoretical model of LARS with the aspects of shock waves, cavitation and thermal effect has been established, and the results have proven the safety of the LARS. Thirdly, using bovine muscle and fat pig to do the biological experiments, it is concluded that the relationship between the damage sizes with the laser parameters. Using high speed camera and hydrophone probe to explore the process of laser pulse act on the tissue organization under water, it has been concluded that the relationship between the lesion and the parameters of pulse energy with water layer. Finally, the practicability of LARS has been verified by using the ICR mouse embryos to simulate clinical surgery.