Chapter 11 Episiotomy and tears

David T Y. Liu

CHAPTER CONTENTS

Types of incision 85

Medial incision 85

Mediolateral Incision 85

J-shaped incision 85

Technique 86

Timing 86

Do 87

Do not 87

Repair of an episiotomy 88

Resuturing episiotomies 88

Tears in the perineum 89

Consequences of perineal trauma for women 90

Episiotomy is the term used for an incision in the perineum. Not all women require an episiotomy for delivery but considerable experience is necessary to determine when it is not needed. This incision is made:

• when a perineal tear is imminent, thus avoiding uncontrolled damage

• to relieve pressure on the soft preterm fetal head

• to expedite delivery when birth is delayed by an unyielding perineum

• to provide adequate room for assisted delivery.

TYPES OF INCISION

Medial incision

Medial incisions are made in the anatomical plane and are comfortable. There is less bleeding, and they are easy to repair. However, access is limited and the incision carries the risk of extension into the rectum, hence it is only used by someone experienced (Figure 11.1a).

Figure 11.1 (a) Medial incision, (b) mediolateral and (c) J-shaped incision.

Mediolateral Incision

This incision is safe, easy to perform, and thus the most commonly used. It is associated with least risk of anal sphincter damage. The cut must begin at the mid-point of the fourchette and is directed towards the ischial tuberosity into the ischiorectal pad of fat (Figure 11.1b).

J-shaped incision

This type of incision has the advantage of the medial incision and provides better access than the mediolateral approach. The lateral incision is made tangential to the brown of the anus (Figure 11.1c). It is excellent for the experienced surgeon.

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TECHNIQUE

• An existing epidural can provide adequate anaesthesia; if not infiltrate with a local anaesthetic. The fingers are placed inside the introitus to protect the presenting parts of the fetus (Figures 11.2 and 11.3).

• The index and middle fingers are placed in the introitus along the direction of intended cut. The thumb is apposed to stabilise the perineum. A single cut 3 cm long starting from the mid-point of the fourchette is made with scissors.

• In the J-shaped incision, the thumb, middle and index fingers are apposed in the midline of the fourchette. The tip of the thumb is placed 0.5–1 cm above the brown of the anus. A midline incision to the tip of the thumb is made. The thumb and fingers are kept firmly apposed. The scissors are then rotated to align transgentially to the brown perianal area and another incision is then made (Figure 11.4).

Figure 11.2 Using the fingers the fourchette is drawn away from the presenting part of the fetus before infiltration.

Figure 11.3 Infiltration of local anaesthetic in fan formation starting either at (a) the middle of the fourchette, or (b) near the ischial tuberosity to cover the area of the incision.

Figure 11.4 Performing a J-shaped episiotomy.

TIMING

Episiotomy should be performed:

• when tearing of the vagina becomes obvious. This is indicated by a show of fresh blood when the presenting part of the fetus distends the perineum as the mother pushes

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• when the overstretched perineum may be seen to tear

• electively with a thick unyielding perineum

• electively before traction on the forceps or before proceeding to breech delivery (when a breech is on the perineum).

DO

• Place women in the lithotomy position.

• Unless in an emergency, ensure there is adequate anaesthesia. Epidural anaesthesia may not be sufficient. Pudendal block anaesthetises only S2–S4 hence perineal infiltration with additional local anaesthetic is required to cover S5 of the perianal area (Figure 11.5).

• Remember the total amount of local anaesthetic used should not exceed 200 mg of lidocaine. This is especially important in women who have been given an epidural block.

• The pudendal nerve enters the pudendal canal approximately 1 cm below and 1 cm cephalad to the ischial spine when the woman is supine. The pudendal vessels are beside the nerves (Figure 11.6), therefore aspirate back before infiltration to prevent intravascular injection.

• Perform episiotomy with one or two strokes and not with multiple bites.

• In repeat episiotomy follow the previous properly made incisions.

• If an episiotomy must be made before the perineum is fully stretched by the presenting part of the fetus, simulate that situation by applying gentle traction on the perineum before making the incision. This will reduce the bulk of tissue incised, hence minimising bleeding and trauma.

• Tie off or place a clip on any spurting vessels to reduce blood loss. For the same reason repair episiotomies as soon as possible.

• Ensure the apex of the incision is identified before repair. If there is extension into the fornices a general anaesthetic or epidural block will aid proper exploration of damage and subsequent repair.

• Check the vaginal incision for any gaps in the suturing. Finally examine the rectal aspect of the incision. Any stitch through into the rectum should be cut to prevent infection and fistula formation. Ensure haemostasis is achieved.

• Consider subcutaneous sutures for the skin.

Figure 11.5 Dermatomes of the perineum. Perianal area is supplied by S5.

Figure 11.6 The pudendal nerve crosses the ischial spine medial to the pudendal artery.

DO NOT

• Perform an episiotomy as a routine.

• Perform the episiotomy too early because vaginal delivery may not be possible, and blood loss and discomfort are increased when women receive both a perineal and an abdominal incision.

• Incise beyond an obstruction to ready delivery due to a thick or unyielding posterior fourchette (Figure 11.7).

• Incise beyond the bony ischial tuberosities. Outlet obstruction due to bony structures is not relieved by an episiotomy. A generous episiotomy is not generous for the woman.

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• Make an episiotomy before rotation with Kjelland’s forceps. Vaginal delivery may not be achieved and rotation can extend the episiotomy.

• Leave any vaginal pack behind.

• Pull stitches too tight. This only increases discomfort and oedema.

Figure 11.7 Obstruction caused by unyielding posterior fourchette (shaded) area

REPAIR OF AN EPISIOTOMY

• The mother should be in the lithotomy position. Cleanse the surgical field, drape and maintain aseptic technique. Commence suturing from above the apex and appose the vaginal mucosa with continuous loose locking stitches placed 1 cm apart and 1 cm from the edge of the wound. Tie off at the vaginal mucocutaneous junction of the fourchette (Figure 11.8). Ensure anatomical apposition especially at hymenal remnants and mucocutaneous junction.

• This is followed by interrupted sutures placed perpendicular to the skin (Figure 11.8b). These sutures occlude any dead space and appose the subcutaneous tissue and the levator ani and perineal muscles. Avoid putting sutures through the rectal mucosa.

• The subcutaneous sutures are placed 1 cm deep and 1 cm apart to close the cutaneous wound. Polyglactin 910 sutures, which produce less tissue reaction and less pain during suture removal are recommended (Figure 11.8c, d).

• Check the vagina to ensure no gaps are present in the suture line and haemostasis is achieved. Perform a rectal examination to exclude any stitch which may have come through the rectal mucosa or the presence of a haematoma. Any rectal stitch must be cut. A haematoma must be evacuated.

Figure 11.8 Repair of an episiotomy: (a) episiotomy, (b) continuous locking vaginal stitches and interrupted sutures, (c) subcutaneous sutures and (d) repair complete. Steps (c) and (d) can be replaced by interrupted sutures.

RESUTURING EPISIOTOMIES

Breakdown of an episiotomy often follows infection of a haematoma. The following procedure should be adopted:

• Take swabs from the infected wound and vagina for bacterial culture.

• Epidural or general anaesthesia facilitates proper repair.

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• The old episiotomy must be opened up in total, any haematoma if present evacuated, the wound edges freshened and the repair effected by interrupted sutures to allow drainage.

• Superficial dehiscence of the wound edges need not be resutured. Keeping the wound clean by regular bathing will promote rapid healing by secondary intention.

• Prescribe approximate broad-spectrum antibiotics.

TEARS IN THE PERINEUM

Eighty-five per cent of vaginal deliveries are associated with some perineal trauma. These are graded as:

• First degree – superficial lacerations, skin only, underlying muscles not damaged.

• Second degree – lacerations involving tearing of perineal muscles.

• Third degree – damage involving partial or complete disruption of the anal sphincter. These have an incidence of 2%, and are subdivided into:

• less than 50% external sphincter injured

• more than 50% external sphincter affected

• torn internal anal sphincter.

• Fourth degree – there is complete disruption of the external and internal sphincters and the rectal mucosa.

Tearing is associated with:

• the woman’s tissue type, ethnicity, age and health

• primiparous delivery

• prolonged second stage of labour

• narrow suprapubic arch

• poorly flexed head and occipitoposterior position

• precipitate labour

• big baby (more than 4000 g)

• shoulder dystocia

• assisted vaginal delivery (e.g. forceps, but much less with ventouse extractions).

Superficial grazes and tears, if they are not bleeding, can be left. Second degree tears are repaired as for episiotomies. Skin edges, because they are ragged, may need interrupted rather than subcutaneous sutures.

Third and fourth degree tears are associated with 4% of vaginal deliveries with mediolateral episiotomy. Severe tears are more common in the nullipara (4%) birthweight over 4 kg (2%), occipitoposterior position (3%), long second stage (4%) and forceps delivery (7%).

Repair of a third degree tear requires:

• Epidural or general anaesthesia (allow anal sphincter to relax and facilitate adequate repair).

• Continuous suture to repair the rectal mucosa. Commence above the apex of the tear; the mucosa is everted into the rectum. Tie-off at the mucocutaneous junction (Figure 11.9a). Use monofilament suture if available, e.g. polyglactin 910.

• The vaginal mucosa is repaired as for an episiotomy (Figure 11.9b).

• The severed ends of the rectal sphincter, which usually retract, are identified and apposed by interrupted sutures (Figure 11.9c). End-to-end repair of the sphincter may result in poorer subsequent function if the ends retract. Overlapping the ends of the sphincter provides more perineal bulk and better function. The anus should accommodate a finger after the sphincter muscles are approximated. The skin is apposed by subcutaneous and interrupted sutures (Figure 11.9d). Ensure that the vaginal introitus accepts two fingers at the end of the repair.

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• Avoid constipation. A low-fibre diet and faecal softeners are advised, e.g. lactulose and Fybogel for 10 days. Do not use oil-based aperients. They inhibit healing of wound edges and encourage recto-vaginal fistula formation.

• Prophylactic antibiotics reduce infection and wound dehiscence. Use metronidazole and broad-spectrum antibiotics.

• Prescribe adequate postoperative analgesia.

• Advise elective caesarean section for subsequent births since further vaginal delivery increases risk of anal incontinence.

• Clear documentation of findings and management is essential.

• Ensure follow-up and review.

Figure 11.9 Repair of third-degree tear. Repair of (a) rectal mucosa, (b) vaginal mucosa and (c) rectal sphincter. (d) Subcuticular sutures.

CONSEQUENCES OF PERINEAL TRAUMA FOR WOMEN

• In 10% pain and discomfort will last 3–18 months after delivery.

• 20% will experience superficial dyspareunia for about 3 months.

• 3–10% report faecal incontinence (30% flatus incontinence).

• 20% experience urinary incontinence.

• Occult anal sphincter damage occurs in 36% after vaginal delivery and is evident in 70% (range 54–88%) despite repair of third and fourth degree tears.

Review women with severe tears 6 months or a year after delivery. Box 11.1 gives further information on third degree tears.

Box 11.1 Third degree tears: faecal incontinence

• About 13% of women experience a degree of incontinence, usually flatus, or rectal urgency after vaginal delivery.

• Faecal incontinence is due to nerve and external and internal anal sphincter injury. Both nerve and muscle are damaged when injury is severe.

• Mediolateral episiotomy may not prevent third degree tears. Two-thirds of third degree tears occur in women with an episiotomy.

• Poor repair will result in subsequent sphincter defect with 50% of women having a degree of incontinence (flatus, faecal).

• About 10% of women may experience wound disruption necessitating further surgery.

• All women with third degree tears should be reviewed 3 months after surgery.

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