Perineal tears

Incidence

• 70% of vaginal childbirth leads to some form of vaginal or perineal injury

Classification

• First-degree: injury to skin and subcutaneous tissue of the perineum and vaginal epithelium only
• Second-degree: laceration extends into fascia and musculature of perineal body, including the deep and superficial transverse perineal muscles and fibres of pubococcygeus and bulbocavernosus. Anal sphincter remains intact.
• Third-degree: laceration involves some or all of the fibres of the anal sphincter complex
  • 3a: <50% external sphincter
  • 3b: >50% external
  • 3c: both external and internal
• Fourth-degree: injury to the perineum involving both anal sphincter complexes and anal mucosa

Repair:

• Choice of suture
  • Synthetic absorbable such as Vicryl or Vicryl Rapide (previously catgut)
• Indications:
  • We would be involved with third and fourth degree tears
• Goals:
  • Restore continuity of both external and internal anal sphincters
    • Create a muscular cylinder >2cm thick and >3cm long
    • Meticulous haemostasis and anatomical re-approximation of all structures
  • Create a thick perineal body and rectovaginal septum
  • Lengthen the anal canal and restore a functional high-pressure zone within it
• Repair
  • Anal mucosa
    • Repair torn anal mucosa with continuous 3/0 Vicryl
  • Sphincter repair
    • Internal sphincter - usually retracts laterally and superiorly - seen as a thickened, pale pink, shiny tissue just above the anal mucosa. Repair continuously.
    • EAS - often retracts laterally. Plicate the severed ends with two or three interrupted figure-of-eight sutures.
  • Rebuild the distal rectovaginal septum and perineal body
    • Interrupted 2/0 Vicryl
  • Repair vagina
    • Reapproximate vaginal epithelium, including the apex of any episiotomy
      • Match landmarks - hymenal ring, vermillion border
      • Loose, continuous, non-locking suture
    • Reapproximate perineal body and bulbocavernosus muscle (use same suture as above, continuing on - 'transitional suture'
      • Need to realign the muscles to allow skin closure with minimal tension

(A) Fourth-degree laceration.

(B) The torn anal mucosa is repaired using a running stitch, but interrupted stitches are also acceptable.

(C) The internal anal sphincter should be properly identified and repaired as a separate layer.

(D) The external sphincter is then identified and repaired. The repair consists of either end-to-end or overlapping plication of the disrupted external anal sphincter and capsule using interrupted or figure-of-eight sutures.