title: Influence of difficulty of instrumentation with vacuum on the rate of levator ani muscle avulsion identified by 3-4 d transperineal ultrasound.
abstract: OBJECTIVE
  Evaluation of the influence of difficulty of instrumentation with vacuum on the rate of levator ani muscle (LAM) avulsions.
  
  
  METHODS
  Prospective observational study with 86 nulliparous women with at term gestation who required instrumentation with vacuum to complete fetal extraction. After every delivery, each explorer reported the number of vacuum tractions needed to complete fetal extraction, as well as the subjective complexity of the instrumentation. LAM avulsion rate was assessed by 3D-4D transperineal ultrasound evaluation 6 months after delivery.
  
  
  RESULTS
  Seventy nine cases were evaluated and classified as either "easy" delivery (below three vacuum tractions; n = 49) or "difficult" delivery (three or more vacuum tractions; n = 30). No differences in obstetric characteristics were observed between study groups, with the following exceptions: fetal head circumference (34.8 ± 2.7 versus 35.2 ± 1.1; p = .013) and fetal weight at birth (3260 ± 421 versus 3500 ± 421; p = .016). No statistically significant differences between study groups were observed in LAM avulsion rate (36.7 versus 30%) and levator hiatus area (cm2) at rest (18.44 ± 3.95 versus 17.75 ± 3.90).
  
  
  CONCLUSIONS
  The number of vacuum tractions needed to complete fetal extraction is not associated to a higher LAM avulsion rate nor with differences in levator hiatus area.
authors.affiliation: a Hospital Universitario de Valme, Obstetrica y Ginecología , Sevilla , España.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: García Mejido
authors.affiliation: a Hospital Universitario de Valme, Obstetrica y Ginecología , Sevilla , España.
authors.forename: Paloma
authors.initials: P
authors.lastname: De la Fuente Vaquero
authors.affiliation: b Universidad de Sevilla , Sevilla , Andalucía , España.
authors.forename: Ana
authors.initials: A
authors.lastname: Fernández Palacín
authors.affiliation: a Hospital Universitario de Valme, Obstetrica y Ginecología , Sevilla , España.
authors.forename: Adriana
authors.initials: A
authors.lastname: Aquise Pino
authors.affiliation: a Hospital Universitario de Valme, Obstetrica y Ginecología , Sevilla , España.
authors.forename: María José
authors.initials: MJ
authors.lastname: Bonomi Barby
authors.affiliation: a Hospital Universitario de Valme, Obstetrica y Ginecología , Sevilla , España.|b Universidad de Sevilla , Sevilla , Andalucía , España.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Sainz Bueno
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D017063:Outcome Assessment, Health Care; D017773:Pelvic Floor / Q000000981:diagnostic imaging / Q000293:injuries*; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D014463:Ultrasonography; D014620:Vacuum Extraction, Obstetrical / Q000009:adverse effects*
keywords: Pelvic floor; levator ani muscle; transperineal ultrasound; vacuum