What is the management and treatment for a laceration due to labor?

Classification and Management of Obstetric Perineal Lacerations

All obstetric perineal lacerations require systematic classification through visual inspection and mandatory digital rectal examination, followed by degree-specific repair using continuous non-locking absorbable sutures, with third- and fourth-degree tears requiring operating room repair, prophylactic antibiotics, and sequential closure from deep to superficial structures. 1, 2

Classification System and Diagnostic Approach

Mandatory Examination Components

• Perform digital rectal examination on every patient after vaginal delivery, as up to 35% of anal sphincter injuries are missed without rectal examination 2
• Ensure adequate lighting and proper patient positioning before examination to prevent misclassification of injury severity 2
• Systematically assess involvement of skin, perineal muscles, anal sphincter complex (external and internal), and rectal mucosa 1, 2

Four-Degree Classification

• First-degree: Skin and vaginal mucosa only, no muscle involvement 3, 4
• Second-degree: Involves perineal muscles but not the anal sphincter 3, 4
• Third-degree: Extends into or through the anal sphincter complex (external anal sphincter ± internal anal sphincter) 1, 5
• Fourth-degree: Complete disruption through anal sphincter and rectal mucosa 1, 6

Management by Laceration Degree

First-Degree Lacerations

• For hemostatic first-degree tears, use skin adhesive or leave unsutured rather than traditional suturing, as this reduces pain and procedure time with equivalent functional outcomes 2, 3
• If suturing is chosen, use continuous non-locking subcuticular technique with absorbable suture material 7
• Conservative care without suturing is appropriate when there is no anatomic distortion 3

Second-Degree Lacerations

• Repair in layers using a single continuous non-locking suture throughout the entire repair 1, 3
• Begin by reapproximating vaginal epithelium, underlying muscularis, and rectovaginal fascia to the hymenal ring 1
• Transition to axial plane and reapproximate bulbocavernosus and transverse perineal muscles in running, continuous, non-locking fashion 1
• Consider leaving perineal skin unsutured or using skin adhesive after repairing deeper layers, as this reduces pain, dyspareunia, and improves breastfeeding rates at 3 months 2
• If closing skin, use running, continuous, non-locking, subcuticular, deep dermal technique 1

Third- and Fourth-Degree Lacerations (OASIS)

Perioperative Setup

• Transfer to operating room for repair with adequate lighting, visualization, and exposure 1, 6
• Administer regional or general anesthesia (local anesthesia insufficient) 1, 6
• Place Foley catheter before initiating repair 1, 6
• Count all surgical instruments, sponges, and sutures pre- and postoperatively 1, 6

Antibiotic Prophylaxis

• Administer prophylactic antibiotics before repair, as this reduces wound complications from 24.1% to 8.2% 1, 6
• First-generation cephalosporin: cefazolin 2g 1
• Second-generation cephalosporin: cefoxitin 2g 1
• Penicillin-allergic: gentamicin 5 mg/kg plus clindamycin 900 mg or metronidazole 500 mg 1

Vaginal Preparation

• Perform surgical-site preparation with povidone-iodine 1, 6
• Use chlorhexidine gluconate if patient is allergic to iodine 1, 6

Sequential Repair Technique (Deep to Superficial)

Fourth-Degree Tears:

1. Anorectal mucosa: Close with interrupted or continuous non-locked 3-0 or 4-0 delayed absorbable sutures (polyglactin or poliglecaprone) 6
2. Internal anal sphincter (IAS): Identify and repair separately using end-to-end technique with mattress or interrupted 3-0 delayed absorbable sutures, as IAS repair improves 1-year anal incontinence rates 2, 6
3. External anal sphincter (EAS): Use overlapping technique rather than end-to-end, as overlapping repair reduces fecal urgency and lowers anal incontinence scores at 1 year 6
4. Proceed with rectovaginal fascia, perineal body, perineal muscles, and vaginal/perineal skin as described for second-degree tears 1, 6

Third-Degree Tears:

• Follow same principles but begin with IAS (if involved) and EAS repair 2
• Use 3-0 delayed absorbable suture for sphincter repairs 2

Critical Pitfalls to Avoid

• Failure to perform digital rectal examination leads to 35% missed anal sphincter injuries 2
• Using locked sutures creates excessive tension causing tissue necrosis 6
• Failure to identify and repair the IAS separately leads to persistent anal incontinence 6
• Inadequate lighting causes misclassification of injury severity 2
• Inappropriate repair technique and lack of surgeon experience increase infection (19.8%) and dehiscence (24.6%) rates 2

Postoperative Management

Pain Control

• First-line: acetaminophen and ibuprofen 1, 6
• Apply ice packs to perineum 1, 6
• Avoid opiates unless absolutely necessary, as need for opiates suggests infection or repair problem 3

Bowel Management

• Prescribe stool softeners (polyethylene glycol 4450 or mineral oil) twice daily for 6 weeks postpartum to achieve toothpaste consistency stools 1, 6
• Osmotic laxatives lead to earlier bowel movements and less pain during first bowel movement 3
• Preventing constipation is critical to avoid wound disruption 6

Bladder Management

• Maintain Foley catheter until postoperative day 1 for OASIS repairs 2, 6
• Perform voiding trial to ensure adequate bladder function 2, 6

Wound Care

• Sitz baths twice daily until first wound check 1, 7
• Keep perineal area clean and dry 7
• Daily cleaning under running water, particularly after bowel movements 7

Follow-Up

• Arrange early follow-up within 2 weeks, ideally in specialized postpartum perineal clinic 1, 6
• Document laceration type and repair technique clearly 1, 6
• Educate patient on degree of injury and importance of close follow-up 1, 6
• If concern for anal sphincter compromise, perform endoanal ultrasound to assess full extent of damage 1

Expected Complications and Monitoring

• OASIS is associated with 29-53% flatal incontinence and 5-10% fecal incontinence in first 6 months postpartum 2
• Overall infection rates after perineal trauma range from 0.1% to 23.6% 2
• Overall dehiscence rates range from 0.21% to 24.6% 2
• Wound complications lead to worsened physical, emotional, and sexual satisfaction persisting up to 9 months postpartum 2