title: Performing ICSI using an injection pipette with the smallest possible inner diameter and a long taper increases normal fertilization rate, decreases incidence of degeneration and tripronuclear zygotes, and enhances embryo development.
abstract: OBJECTIVE
  To compare the efficacy of two types of injection pipette used for ICSI, one with a larger (5-7 microns) inner diameter and a shorter taper with that inner diameter, and another with the smallest (3-5 microns) possible inner diameter and a longer taper with that inner diameter.
  
  
  METHODS
  Retrieved oocytes at metaphase II stage were injected using one of two types of injection pipette, in 33 and 94 cycles, respectively, in a total of 127 cycles in 108 patients.
  
  
  RESULTS
  In comparison to the injection pipette with a larger (5-7 microns) inner diameter and a shorter taper with that inner diameter, the injection pipette with the smallest (3-5 microns) possible inner diameter and a longer taper with that inner diameter increased normal fertilization rate ((70 +/- 3.6)% vs. (86 +/- 2.2)%; P = .001; mean +/- SEM); decreased the incidence of degeneration ((14 +/- 2.4)% vs. (5 +/- 1.4)%; P = .001) and tripronuclear zygotes ((1.0 +/- 0.35)% vs. (0.1 +/- 0.21)%; P = .03); increased Day-2 diploid embryos ((69 +/- 3.7)% vs. (85 +/- 2.2)%; P = .001) and good-quality Day-2 diploid embryos ((67 +/- 4.0)% vs. (79 +/- 2.4)%; P = .03), all per injected oocyte; and increased the number of blastomeres per good-quality Day-2 diploid embryo ((3.0 +/- 0.21 vs. 3.8 +/- 0.12; P = .0003).
  
  
  CONCLUSIONS
  Performing ICSI using an injection pipette with the smallest (3-5 microns) possible inner diameter and a longer taper with that inner diameter maximizes normal fertilization rate, minimizes the incidence of postinjection degeneration and tripronuclear zygotes, and enhances embryo development.
authors.affiliation: Toronto Fertility Sterility Institute, Toronto, Ontario, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Yavas
authors.forename: S
authors.initials: S
authors.lastname: Roberge
authors.forename: F
authors.initials: F
authors.lastname: Khamsi
authors.forename: P
authors.initials: P
authors.lastname: Shirazi
authors.forename: M W
authors.initials: MW
authors.lastname: Endman
authors.forename: J C
authors.initials: JC
authors.lastname: Wong
mesh_terms: D000328:Adult; D004622:Embryo, Mammalian / Q000502:physiology*; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000209:etiology / Q000628:therapy; D007248:Infertility, Male / Q000209:etiology / Q000628:therapy; D008297:Male; D008423:Maternal Age; D008845:Microinjections / Q000295:instrumentation*; D008875:Middle Aged; D009865:Oocytes / Q000502:physiology; D011247:Pregnancy; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000295:instrumentation* / Q000379:methods; D015053:Zygote