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Simulation

Obstetric Laceration Repair

Module

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Learning Objectives

By the end of this unit, you should be able to do the following:

  • Describe normal perineal anatomy
  • Define fecal continence physiology
  • List risk factors for sphincter injury
  • Correctly identify each level of perineal laceration
  • Adequately perform perineal laceration repair in a simulated setting
  • List complications of obstetrical anal sphincter injury

Normal Anatomy

Normal perineal anatomy.
Image used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management. 2007.
Normal perineal anatomy.
Image used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management. 2007.

Anatomy of the Anal Sphincter

The external anal sphincter is not truly a “donut” in shape, but a bulky longitudinal muscle.

Anal sphincter anatomy.
Image used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management. 2007.
Anal sphincter anatomy.
Image used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management. 2007.

Anal Continence Physiology

  • Solid stool held above the anal canal
  • Internal anal sphincter (IAS) resting tone and external anal sphincter (EAS) tonic activity keep the anal canal closed
  • Distention of the rectum causes a transient relaxation of the IAS
  • Sensory nerves accomplish “sampling”
  • The EAS maintains continence during sudden filling
  • The IAS maintains continence at rest

Predictors of Sphincter Disruption

  • Vacuum delivery (Odds Ratio [OR]: 3.98)*
  • Forceps delivery (OR: 5.50)
  • Midline episiotomy (OR: 3.82)
  • Increased fetal birth rate: Mean difference 192.88 grams
  • Primiparity (OR: 3.24)
  • Asian ethnicity (OR: 2.74)
  • Intraocular lens (IOL) (OR: 1.08)
  • Labor augmentation (OR: 1.95)
  • Persistent occiput posterior (OP) (OR: 3.09)

*1.0 = No operative delivery or no episiotomy

Source: Pergialiotis V, Vlachos, D, Protopapas A, Pappa K, & Vlachos G. Risk factors for severe perineal lacerations during childbirth. Int J Gynaecol Obstet 2014;125:6-14

Prevention of Sphincter Disruption

  • Perineal massage
    • Decreased third-degree and fourth-degree tears when used in the second stage of labor
    • This was compared with a “hands off” technique
  • Perineal support
    • Varying outcomes with support
    • Support techniques not described, thus difficult to recommend a practice
  • Warm compress: Application of warm compresses during pushing reduces the incidence of third- and fourth-degree lacerations
  • Birth position: No clear benefit of any upright position compared with a lying down position in patients with an epidural
  • Delayed pushing
    • Delayed pushing (1–3 hours from full dilatation) compared with immediate pushing (0–1 hours from full dilatation)
    • No differences in rates of perineal laceration

Source: Obstet Gynecol. Practice Bulletin 165. 2016 Jul;128(1):e1-e15

Identification of Laceration

  • First-degree laceration is laceration of the vaginal epithelium or perineal skin only
  • Second-degree laceration is defined as laceration of the perineal muscles, but not the anal sphincter complex. See the traditional interrupted method of perineal repair below.
Continuous stitch to vaginal wall.
Continuous, locking (blanket) stitch to vaginal wall.
Interrupted stitch to perineal muscles.
Interrupted sutures to perineal muscles.
Interrupted stitch to skin.
Interrupted stitches to skin.

Images used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management, 2007.

Identification of Laceration

  • IAS: Internal anal sphincter
  • EAS: Eternal anal sphincter
  • Third-degree laceration is defined as disruption of the anal sphincter muscles
    • 3a: < 50% thickness of EAS
    • 3b: > 50% thickness of EAS
    • 3c: IAS also involved
  • Fourth-degree laceration (4) is defined as disruption of the anal sphincter complex with involvement of the anal epithelium
Anal sphincter anatomy.
Image used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management, 2007.

Approach to Repair

  • Repair as soon as possible after childbirth to decrease blood loss and risk of infection
  • Antibiotics: At the time of repair, given a single dose of a secondgeneration cephalosporin (cefotetan or cefoxitin)
  • Maintain accurate sponge counts
  • Proper lighting
  • Adequate anesthesia
  • Consider postoperative Foley catheter if significant edema
  • Close dead space to decrease hematoma risk
  • Do not overtighten sutures
  • Ensure good anatomic alignment of wound edges
  • Always perform a rectal exam

Instrumentation

  • Needle driver
  • Suture scissors
  • Allis clamps
  • Smooth thumb forceps
  • Single-tooth thumb forceps
  • Suture
  • Self-retaining retractor, such as a Gelpi®

The Sultan anal sphincter trainer with a central replaceable block has been designed for hands-on teaching.

Sultan anal sphincter trainer.
Image used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management, 2007.

Approach to Repair: Suture

  • Plain catgut
    • Mechanism of absorption: Proteolysis and phagocytosis
    • Tensile strength: 7 lb, half-strength in 4-6 days
    • Inflammatory response: Highest
    • Absorption: 70 days
  • Chromic catgut
    • Mechanism of absorption: Proteolysis and phagocytosis
    • Tensile strength: 8 lb, half-strength in 10-14 days
    • Inflammatory response: High
    • Absorption: 90 days
  • Polyglycolic acid and polygalactin 910 (Dexon/Vicryl)
    • Mechanism of absorption: Hydrolysis
    • Tensile strength: 9.6 lb, half-strength in 21 days
    • Inflammatory response: Low
    • Absorption: 60–90 days
  • Polydioxanone (PDO, PDS)
    • Mechanism of absorption: Slow hydrolysis
    • Tensile strength: 70% at 14 days, 25% at 42 days
    • Inflammatory response: Low
    • Absorption: Minimal in first 6 weeks, complete at 6 months
  • Suture material
    • Cochrane review of 18 randomized controlled trials (RCTs) comparing absorbable synthetic polygalactin 910 (Vicryl) or
    • Polyglycolic acid (Dexon) versus catgut suture for perineal repair
  • Absorbable synthetic suture
    • Decreases perineal pain, analgesic use, and dehiscence at 10 days
    • No difference at 3 months
    • Increases need for suture removal up to 3 months

Source: Kettle C. Cochrane Database Syst Rev 2010

Internal Anal Sphincter

A grade 3b tear with an intact internal anal sphincter (IAS). The external sphincter (EAS) is being grasped with Allis forceps. Note the difference in appearance of the paler IAS and darker EAS.

Internal anal sphincter.
Image used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management, 2007.

External Anal Sphincter

External anal sphincter end-to-end posterior, inferior, superior and anterior (PISA) repair.
External anal sphincter end-to-end posterior, inferior, superior and anterior (PISA) repair.
External anal sphincter overlapping repair.
External sphincter overlapping repair.

Images used with permission from the Cine-Med, Inc Image Library ©2016, www.cine-med.com.

  • Cochrane review of six random controlled trials involving 568 women, comparing efficacy of overlap repair versus end-to-end repair for obstetric anal sphincter injuries
  • No difference in perineal pain, dyspareunia, flatal incontinence at 12 months
  • Decreased fecal urgency in overlap group at 12 months
  • No difference in fecal urgency at 36 months

Source: Fernando RJ. Cochrane Database Syst Rev, 2013

  • End-to-end repair of the external sphincter using two mattress sutures.
    • Interrupted sutures
    • Delayed absorbable suture
    • Include the fascial sheath
External anal sphincter end-to-end posterior, inferior, superior and anterior (PISA) repair.
Image used with permission. Springer: Sultan, Thakar, and Fenner (Eds). Perineal and anal sphincter trauma: diagnosis and clinical management, 2007.

Second-Degree Laceration Repair

  • Perineal body
    • Reapproximate vaginal mucosa
    • Reapproximate perineal muscles, including the bulbocavernosus
    • Interrupted or running sutures
    • 2-O or 3-O delayed absorbable
  • Perineal closure
    • Close perineal skin
    • Subcuticular, running
    • 4-O delayed absorbable suture
    • Some health care providers choose to leave the perineal skin open

Complications and Follow-up

  • Complications
    • Bleeding
    • Pain o Infection
    • Wound dehiscence
    • Flatal and fecal incontinence
  • Follow-up
    • Implications for future deliveries

Infection and Wound Dehiscence

  • Infection
    • Vagina heavily colonized by bacteria
    • Fecal contamination at delivery common
    • Liberal use of irrigation with antiseptic
    • Early administration of antibiotics to prevent wound breakdown and sepsis: Consider coverage for Methicillin-resistant Staphylococcus aureus, or MRSA (sulfamethoxazole/trimethoprim)
  • Wound dehiscence
    • Early administration of antibiotics
    • Operation room inspection, irrigation, and debridement
    • Secondary closure once infection is treated

Fecal and Flatal Incontinence

Outcomes after primary repair of third and fourth degree lacerations—35 studies

  • Anal incontinence (flatal and flatal + fecal): 15–61% (N = 35; mean = 39%)
  • Fecal incontinence only: 2–29% (N = 25; mean = 14%)
  • Fecal urgency: 6–28%
  • Sphincter defects noted on ultrasonography, despite repair: 34–91%

Source: Sultan AH, Thakar R, Fennder DE. Perineal and Anal Sphincter Trauma, 2008

Follow Up: Future Deliveries?

  • Limited data, thus limited guidelines
  • Harkin, et al: Anal sphincter injuries occur in 4.4% of women who previously had injury
  • Sangallli, et al: Patients with third-degree lacerations did not have increased anal incontinence (flatal or fecal + flatal incontinence) symptoms after subsequent delivery
  • Poen, et al:
    • AI = 34% in those without subsequent delivery
    • AI = 56% in those with previous injury and 2nd delivery

Source: Harkin. Eur J Obstet Gynecol Reprod Biol 2003 Sangalli. Aust N Z J Obstet Gynaecol 2000 Poen. Br J Surg 1998

Contributing Authors

  • Sarah Appleton, MD Assistant Professor, University of Colorado
  • Tricia Huguelet, MD Assistant Professor, University of Colorado

Produced in collaboration with The Society for Academic Specialists in General Obstetrics and Gynecology.

Version 1.0, posted January 25, 2017

The CREOG Surgical Skills Task Force created this simulation as part of a standardized surgical skills curriculum for use in training residents in obstetrics and gynecology.