Injuries of the birth canal

Primary Mother Care describes the repair of episiotomies and first-degree tears; here we describe the repair of more serious injuries. You can nearly always avoid third- degree tears by ''controlled pushing', and by making an episiotomy when this is needed. They follow instrumental deliveries more often than normal ones. Almost all obstetricians meet them sometimes: so recognize this, and don't blame the midwife. She will be upset anyway, and will be tempted to conceal such a tear if you are harsh.

Suture second- and third-degree tears, either within 24 hours of delivery, or after several months, when a tear has epithelialized and is no longer infected. With a recent third- degree tear: (1) Start by stitching the edges of the patient's rectum together. (2) Cover these stitches with a layer of fascia. (3) Suture her anal sphincter with two or three interrupted sutures. (3) Close her vaginal and perineal skin. If a tear is old, you will first have to incise and reflect the skin which has grown over it.

TEARS OF THE BIRTH CANAL LESSER INJURIES If a patient has a second-degree tear, and it is less than 24 hours old, suture it (M 24.1). If it is more than 24 hours old, wait, and sit her in salt baths. Use a bowl of water containing enough salt to make it into half-strength saline. Sit her in this twice a day for an hour; after 2 or 3 days she can continue baths at home. Her tear will heal itself in a few weeks, with little deformity of her perineum. Don't try to excise it, or her introitus will stenose later.

If her cervix is torn, it may have a single tear, which is large enough to sew, or numerous small ones. The bleeding from small tears is most easily controlled by packing, see Section 19.11a. Blood is more likely to be coming from a poorly contracted uterus, for which she needs ergometrine and oxytocin.

If she has a haematoma of her vulva (unusual), incise it at its lowest point, and evacuate the clot. Insert a drain, and suture this in position. If it bleeds severely, pack the cavity for 24 hours. If you don't see the bleeding vessel immediately, don't waste time looking for it. These haematomas are usually unilateral, and cause great pain, and occasionally retention of urine and shock.

If her clitoris is torn (rare), undersew it with continuous catgut. It may bleed severely. Enquire what happened; a common mistake is to support the perineum too vigorously, so as to force the head against the pubis, and tear the tissues over it.

A RECENT THIRD-DEGREE TEAR Repair her tear as soon as possible. Don't wait to let her recover from her labour. If you have to delay [mt]24 hours or there is infection, leave it, and do an elective repair later when it has healed.

CAUTION ! This is not a minor operation. The best chance of success is the first attempt. If you fail, she is condemned, at best, to some episodes of faecal incontinence.

EQUIPMENT. One pair of tissue forceps, 6 haemostats, needle-holders, and round-bodied curved needles. Use No.1 chromic catgut for all tissues except her skin.

ANAESTHESIA. (1) Repair her tear in the labour ward, using local infiltration with 1% lignocaine. Often, she has already had a pudendal block prior to vacuum extraction or forceps. Or, (2) take her to the theatre. Give her a general anaesthetic. Make sure you have a competent assistant.

METHOD. Put her into the lithotomy position, with her buttocks hanging well over the edge of the table. Shine a good light on the wound. Clean it and the skin round it thoroughly. Put a large gauze pack with a tape attached to it into her vagina. This will keep the tear free from blood, but be careful that bleeding does not occur above it. Ask your assistant to retract her vaginal wall while you survey the tear.

If the tear goes high up her rectum and vagina (fortunately quite rare), you will find that there is nothing between her rectal mucosa and her vaginal skin. These two must be repaired in separate layers, so first dissect them free from one another. Lower down, her perineal body separates them, so that there is no problem.

Suture her rectal mucosa with interrupted or continuous sutures, starting at the apex of the tear, and tying the knots outside the lumen of her rectum. Use a round-bodied curved needle.

If the tear is very extensive, pick up her prerectal fascia with a second row of sutures. These will reinforce the first layer.

To close her external sphincter ani, look for the torn ends of this muscle. You will find them lying in little pits on each side of her anus. Often, one side is deeply retracted, so that you have to fish for it.

Define the muscle on each side by dipping into the pits with artery forceps. Pull the end of the muscle up, and put artery forceps across it. Do the same the other side. Bring the artery forceps on each side together, and put your little finger into her anus. It should just go in, but be held firmly. If it is not tight, you have not defined the sphincter properly on each side, so fish again. Then insert three catgut sutures through the muscle to exclude the forceps. Don't tie them until you have removed the forceps, as in A, Fig. 18-17. Take a deep bite with the needle laterally, so as to include the fascia surrounding the muscle. Tie the knots without too much tension, or they may tear out. Check that you have not inserted too many sutures, and made her vagina too narrow. You should be able to insert 2 fingers comfortably.

To close her vaginal skin use a single layer of continuous catgut sutures.

To close her levator ani muscles, take deep bites with the needle each side, so as to take a good hold of the muscles and the fascia covering both their surfaces. These thick sheets of muscle and fascia lie deep on each side of her rectum. Begin at the anal end and join them together.

Put in three to five stitches like this. Leave them united until they are all in place. Then tie them with care, so as to avoid excessive tension.

Suture the skin of her anal margin with a few interrupted catgut sutures. Close the skin of her perineum with interrupted monofilament. Put a dry dressing on her wound.

CAUTION ! Don't close her skin and vaginal wall too tight; leave room for drainage, in case she becomes infected or oozes.

POSTOPERATIVELY, keep her on a fluid diet until the third day. If she does not open her bowels by the 4th or 5th day (unusual), give her a small enema. Give her a normal diet from Day 1. Give her liquid paraffin twice daily for two weeks, starting on the third day. Start salt baths from Day 1.