title: Curved versus straight scissors to avoid 3rd and 4th degree perineal tears: a randomised feasibility study.
abstract: BACKGROUND
  Severe perineal tears sustained during childbirth cause significant distress and morbidity amongst women. The objective of this study was to compare the use of straight scissors for cutting an episiotomy with the use of curved scissors, which are designed to curve away from the anal sphincter.
  
  
  METHODS
  We used a single-centre, randomised feasibility trial. The intervention was the use of curved scissors. Women were recruited during a prenatal visit and randomised in the delivery suite, when it became clear that an episiotomy was required. The feasibility outcomes were the proportion of women able to be recruited, randomised and followed up. We also calculated the incidence of obstetric anal sphincter injury when either straight or curved scissors were used to cut an episiotomy. Other outcomes assessed were pain, length of hospital stay, perineal infection and perineal dehiscence.
  
  
  RESULTS
  Of the 155 patients recruited in the prenatal period, only 20 (12.9%) were eventually randomised at birth. The main reasons for the high loss were that women either did not have a vaginal delivery (38, 24.5%), or they did not need an episiotomy (72, 46.5%). Rates of obstetric anal sphincter injury and other outcomes were similar between groups.
  
  
  CONCLUSIONS
  Anal sphincter injury during childbirth remains an important problem. Although the use of curved scissors provides a theoretical solution, we found that the high attrition rate made feasibility of conducting a suitably powered, randomised trial using the current design untenable. Alternative strategies have been suggested to make any future study more viable.
authors: Royal Brisbane and Women's Hospital, Australia.
authors: Angela
authors: A
authors: Swift
authors: Royal Brisbane and Women's Hospital, Australia. Electronic address: joan.webster@health.qld.gov.au.
authors: Joan
authors: J
authors: Webster
authors: Royal Brisbane and Women's Hospital, Australia.
authors: Annette Mary
authors: AM
authors: Conroy
authors: Royal Brisbane and Women's Hospital, Australia.
authors: Sue
authors: S
authors: Hampton
authors: Royal Brisbane and Women's Hospital, Australia.
authors: Sarah Jane
authors: SJ
authors: Kirby
authors: Royal Brisbane and Women's Hospital, Australia.
authors: Lee
authors: L
authors: Minuzzo
authors: Royal Brisbane and Women's Hospital, Australia.
authors: Rebecca
authors: R
authors: Kimble
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000293:injuries*; D004841:Episiotomy / Q000009:adverse effects* / Q000295:instrumentation* / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D022125:Lacerations / Q000209:etiology / Q000517:prevention & control; D007902:Length of Stay; D007744:Obstetric Labor Complications / Q000601:surgery; D010502:Perineum / Q000293:injuries*; D011247:Pregnancy
keywords: 3rd degree tear; 4th degree tear; Episiotomy; Obstetric anal sphincter injury; Scissors