title: Laser-assisted ICSI: a novel approach to obtain higher oocyte survival and embryo quality rates.
abstract: BACKGROUND
  Degeneration of oocytes occurs even when maximum care is exercised during ICSI, especially when the oolemma is very fragile and/or the zona pellucida is resistant. In order to be able to minimize the risk of degeneration associated with microinjection this study applied a new method: a microhole on the zona pellucida of the oocyte was drilled by laser beam just prior to ICSI to permit the penetration of the microneedle without any trauma.
  
  
  METHODS
  A total of 32 patients (32 cycles) who had one or more previously failed ICSI cycles with a high degeneration rate of oocytes (>20%) were included in the study. Oocytes of the same patients were randomly divided into the study group [laser-assisted ICSI (LA-ICSI)] and the control group [conventional ICSI (C-ICSI)]. The outcomes of the cycles were compared and analysed.
  
  
  RESULTS
  After LA-ICSI compared with C-ICSI, survival rates of oocytes were 99.6 and 84% (P < 0.0001), fertilization rates were 76.6 and 68.6% (not significant) and embryo development rates ( vertical line 6 cells on day 3) were 76.5 and 57.3% (P = 0.0024) respectively.
  
  
  CONCLUSIONS
  Creating a microhole on the zona pellucida of the oocyte by laser beam prior to ICSI provides a less traumatic penetration of the injection needle into the ooplasm and results in lower degeneration and higher embryo development rates than C-ICSI in patients with fragile oocytes.
mesh_terms: D000328:Adult; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000502:physiology*; D005314:Embryonic and Fetal Development; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage; D006801:Humans; D007834:Lasers; D016729:Leuprolide / Q000008:administration & dosage; D008297:Male; D008845:Microinjections / Q000379:methods; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure; D011247:Pregnancy; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D020858:Tissue and Organ Harvesting; D016896:Treatment Outcome; D015044:Zona Pellucida / Q000648:ultrastructure
chemical_list: D005640:Follicle Stimulating Hormone; D016729:Leuprolide