What is the appropriate management for a postpartum patient with a perineal tear, including grading and treatment options?

Perineal Tear Grading and Management

Classification System

Perineal tears are classified into four degrees based on the depth and structures involved, with accurate identification being critical to prevent long-term morbidity including anal incontinence in up to 60% of women with missed or improperly repaired severe tears. 1, 2

The ACOG standardized classification system defines:

• First-degree: Injury to perineal skin and vaginal mucosa only 3
• Second-degree: Injury involving perineal muscles but not the anal sphincter 3
• Third-degree: Injury involving the anal sphincter complex (external and/or internal anal sphincter) 3
• Fourth-degree: Injury extending through the anal sphincter into the anorectal mucosa 3

Prevalence Context

• First-degree tears occur in 5.5-16.4% of vaginal births 2
• Second-degree tears occur in 29.0-35.1% 2
• Third-degree tears occur in 1.8-7.1% 3, 2
• Fourth-degree tears occur in 0-0.3% 2
• Up to 35% of anal sphincter injuries are missed without proper examination 3, 1

Mandatory Diagnostic Approach

After every vaginal delivery, perform a systematic evaluation including visual inspection under adequate lighting, thorough perineal examination, and mandatory digital rectal examination—failure to perform rectal examination results in missing up to 35% of anal sphincter injuries. 4, 1, 2

Critical examination steps:

• Ensure adequate lighting and proper patient positioning before beginning 4, 1
• Inform the patient about the need and reasoning for examination 1
• Perform visual inspection of the entire perineal area 4
• Conduct digital vaginal examination to assess depth 4
• Perform mandatory digital rectal examination on all patients to detect occult anal sphincter involvement 4, 1, 2
• If concern exists for anal sphincter compromise, obtain endoanal ultrasound 4

Common Pitfall

Do not rely solely on visual inspection—always perform digital rectal examination to detect deeper involvement, as this is the single most common cause of missed OASIS. 4, 1

Management by Tear Degree

First-Degree Tears (Hemostatic)

For hemostatic first-degree tears, use skin adhesive or no suturing rather than traditional suturing—this reduces pain and procedure time with equivalent functional outcomes. 1, 2

• If bleeding is controlled, avoid suturing 1, 2
• Skin adhesive is an acceptable alternative if closure is desired 1, 2

Second-Degree Tears

For second-degree tears, repair deeper perineal muscle layers with sutures, but if the skin is hemostatic, use skin adhesive or no suturing for the perineal skin—this reduces pain, dyspareunia, and improves breastfeeding rates at 3 months. 1, 2

• Repair the perineal body muscles with absorbable suture 4
• Leave skin un-sutured if hemostatic 1, 2
• If suturing skin is necessary, use continuous non-locking subcuticular sutures rather than interrupted transcutaneous sutures to reduce pain 4

Third- and Fourth-Degree Tears (OASIS)

For OASIS, immediate referral to an experienced provider is mandatory—if the primary surgeon is inexperienced, pack the wound and safely delay repair up to 8-12 hours until a specialist is available, as inappropriate repair technique significantly increases the already high baseline complication rates of 19.8% infection and 24.6% dehiscence. 3, 1, 5

Pre-operative preparation:

• Administer prophylactic antibiotics: first-generation or second-generation cephalosporin; for penicillin allergy use gentamicin plus clindamycin or metronidazole 4
• Perform vaginal preparation with povidone-iodine or chlorhexidine gluconate if iodine allergy 4
• Ensure regional or general anesthesia for adequate pain control and muscle relaxation 4, 2
• Place Foley catheter before initiating repair 4

Surgical technique:

• Repair sequentially from deep to superficial: anorectal mucosa (if fourth-degree), internal anal sphincter, external anal sphincter, rectovaginal fascia, perineal body muscles, vaginal mucosa, and skin 4, 1
• For internal anal sphincter: use end-to-end technique with mattress or interrupted sutures using 3-0 delayed absorbable suture 4, 1
• For external anal sphincter: use either end-to-end or overlapping technique based on surgeon familiarity—neither technique shows superiority 5
• Use continuous non-locking subcuticular sutures for skin to minimize nerve damage and pain 4
• Count all surgical instruments, sponges, and sutures pre- and postoperatively 4

Post-operative care:

• Maintain Foley catheter until postoperative day 1, then perform voiding trial 4, 1
• Prescribe stool softeners for at least 2-6 weeks to achieve soft stools and prevent strain 4, 5
• Provide acetaminophen and NSAIDs as first-line pain control; reserve opiates only if needed 4, 6
• For women with labor epidural, consider epidural morphine (≤2 mg) with adequate respiratory monitoring for severe tears 6
• Recommend sitz baths twice daily 4
• Apply ice packs for additional pain relief 4, 6
• Arrange follow-up within two weeks, ideally in a specialized postpartum perineal clinic 4, 1
• Inform patient about impact on subsequent births and possibility of anal incontinence 5

Management of Wound Complications

Infected Dehiscence

If wound infection or dehiscence occurs, administer second- or third-generation cephalosporin, or metronidazone with gentamicin (clindamycin for penicillin allergy) for adequate coverage of vaginal and bowel flora. 4

• Perform thorough visual inspection and digital examination to assess extent of dehiscence, presence of infection, and involvement of deeper structures including anal sphincter 4
• Conduct mandatory digital rectal examination to evaluate for occult anal sphincter involvement 4
• If anal sphincter compromise is suspected, perform endoanal ultrasound 4

OASIS Dehiscence

For OASIS dehiscence, refer to a specialized postpartum perineal clinic for expert evaluation—resuturing should only be performed by experienced providers using the same meticulous technique as primary repair. 4

Critical Morbidity Context

OASIS is associated with 29-53% flatal incontinence and 5-10% fecal incontinence in the first 6 months postpartum, causing embarrassment, social isolation, and significantly affecting quality of life—proper identification and repair technique are essential to minimize these devastating outcomes. 3, 1

• Wound complications after OASIS lead to worsened physical, emotional, and sexual satisfaction persisting up to 9 months postpartum 3, 1
• Risk increases with missed diagnosis, inappropriate repair technique, and lack of surgeon experience 3, 1