Episiotomy

A brief history of episiotomy

Episiotomy, also known as perineotomy, is a surgical incision of the perineum and the posterior vaginal wall to enlarge the vulval outlet for the baby to pass through.

Indications of episiotomy

Although episiotomy was designed to reduce the risk of an uncon­trolled perineal tear, it is not without side effects such as postpartum wound pain, sexual dysfunction, and even major perineal tear and incontinence. Current studies have suggested that a restricted ap­proach would be more beneficial when compared to a routine policy. Episiotomy may be considered when:

• tight perineum: as judged by the birth attendant that the risk of perineal tear is higher without an episiotomy

• instrumental delivery: in which the risk of perineal injury is often high

• shoulder dystocia: episiotomy itself does not relieve shoulder dys­tocia but may allow more room for the insertion of the operator’s hand for internal rotation or delivery of the posterior arm.

Types of episiotomy

Among various types of episiotomy, mediolateral and median are the two most commonly used types.

• Mediolateral: oblique incision downwards and outwards from the midpoint of the fourchette to either the right or left. Ideally it is 45 degrees from the vertical line. However, when the fetal head is stretching the perineal skin, an incision line that deviates from vertical by 60 degrees would be more appropriate.

• Median: midline vertical incision commences from the centre of the fourchette and extends downwards towards but not reaching the anus.

When compared to a median incision, a mediolateral incision has the advantages of avoiding bisecting the perineal body, which is es­sential for the integrity of the pelvic floor, and reducing the risk of anal tear (12).

Procedure of mediolateral episiotomy

• Timing: the incision should not be made too early when the fetal head has not distended the perineum, or too late when the fetal head is starting to tear the perineum.

• It should begin in the midline at the fourchette.

• It must be made in one single cut.

• Direction: between 45 degrees from the vertical line (when the fetal head is not stretching the perineum) and 60 degrees (when the fetal head is stretching the perineum) (14).

• Length: it is about 2.5-3 cm. A too-small cut will not increase the vulval outlet sufficiently to facilitate delivery, but may itself form a weak point in the perineal tissues from which a tear could ex­tend. On the other hand, a too-large cut may damage the ipsilat­eral Bartholin’s gland.

Risks and complications of episiotomy

Episiotomy is associated with wound pain, bleeding, and infection. Extension of a perineal or vaginal tear, as well as anal sphincter in­jury may occur. In rare circumstances, an anovaginal fistula may occur if the episiotomy is not repaired properly.

Repair of episiotomy

The aim of episiotomy repair is to achieve haemostasis and tissue reapproximation.

Repair can be done in the labour room provided lighting and ex­posure is adequate. Local anaesthesia can be given for pain control. Prior to repair, a thorough examination should be performed to look for additional cervical or vaginal tears, and whether the anal sphinc­ters are involved. A digital rectal examination would be useful to assess the rectum and anal sphincters.

Absorbable sutures are used such as Vicryl and Polysorb. Repair begins at approximately 1 cm above the apex of the vaginal wound. The vagina is repaired with continuous sutures around 1 cm apart until the hymenal ring is reached. The suture is then brought for­ward to the perineal body where the muscular layer of the peri­neal body is closed with the continuous suture until the posterior apex of the perineal body is reached. Subsequently, the perineal skin is approximated by continuous subcuticular sutures running anteriorly to the introitus and finally, the knot is tied inside the hymenal ring.