Perineal Lacerations

INTRODUCTION:

• A perineal tear is a laceration of the skin and other soft tissue structures (innervated by Pudendal nerve)which, in women, separate the vagina from the anus.
• Perineal tears mainly occur in women as a result of vaginal childbirth, which strains the perineum.
• Tears vary widely in severity.
• The majority are superficial and require no treatment, but severe tears can cause significant bleeding, long-term pain or dysfunction.
• A perineal tear is distinct from an episiotomy, in which the perineum is intentionally incised to facilitate delivery.
• An occult injury to the perineum without noticeable injury occurs in 0.5–2% women following vaginal delivery.
• Perineal hematoma after trauma is due to Rupture of bulbar urethra
• During childbirth, Pubococcygeus is most often injured by a tear of the perineum
• As much as 35% primipara women have shown to have sustained occult sphincter injury as seen on anoendosonogram.

• First-degree tear: laceration is limited to the fourchette and superficial perineal skin or vaginal mucosa
• Second-degree tear: laceration extends beyond fourchette, perineal skin and vaginal mucosa to perineal muscles and fascia, but not the anal sphincter
• Third-degree tear: fourchette, perineal skin, vaginal mucosa, muscles, and anal sphincter are torn; third-degree tears may be further subdivided into three subcategories:
• 3a: partial tear of the external anal sphincter involving less than 50% thickness
• 3b: greater than 50% tear of the external anal sphincter
• 3c: internal sphincter is torn
• Fourth-degree tear: fourchette, perineal skin, vaginal mucosa, muscles, anal sphincter, and rectal mucosa are torn

ETIOLOGY:

• During delivery As the head passes through the pelvis, the soft tissues are stretched and compressed. 
• The risk of severe tear is greatly increased if
• The fetal head is oriented occiput posterior (face forward),
• The mother has not given birth before
• The fetus is large.

PREVENTION:

•  Antenatal digital perineal massage 
• ‘Hands on’ techniques
• Waterbirth and labouring in water 

COMPLICATIONS:

• First and second degree tears rarely cause long-term problems
• Third or fourth degree tear, 60-80% are asymptomatic after 12 months
• Faecal incontinence, faecal urgency,flatus ,chronic perineal pain and dyspareunia 
• Recto vaginal fistula(Improper repair)
• Symptoms associated with perineal tear are not always due to the tear itself, since there are often other injuries, such as avulsion of pelvic floor muscles, that are not evident on examination
• Over-zealous repair after childbirth, using a so-called “husband stitch” to increase vaginal tightness, can exacerbate pain during intercourse