Injuries of the birth canal

Vulva

Lacerations of the vulval skin posteriorly and the para urethral tear on the inner aspect of the labia minora are the common sites. Para-urethral tear may be associated with brisk hemorrhage and should be repaired by interrupted catgut sutures, preferably after introduction of a rubber catheter into the bladder to prevent injury of the urethra.

Perineum

While minor injury is quite common specially during first birth, gross injury is invariably a result of mismanaged  2^nd stage of labour.

Causes

• Over stretching of the perineum- large baby, face to pubis or face delivery, outlet contraction with narrow pubic arch, shoulder delivery (posterior) and forceps delivery
• Rapid stretching of the perineum- rapid delivery of the head during uterine contraction, precipitate labour and delivery of the after coming head in breech
• Inelastic perineum- rigid perineum in elderly primi-gravida, scar of the perineum following previous operations (episiotomy, perineorrhaphy).

Prevention

Proper conduct in the 2^nd stage of labour taking due care of the perineum when it is likely to be damaged, in conditions as mentioned earlier in the chapter is the effective step to prevent undue laceration. The prevention of the perineal injuries in normal delivery has been outline.

Degrees

1^{st degree}– lacerations of the fourchette, lower part of the vagina and the perineal skin but the perineal body remains intact.

2^nd degree- lacerations of the posterior vaginal wall and varying degrees of tear of the perineal body excluding the anal sphincter

3^{rd degree}– injury to the perineum involving posterior vaginal wall and tear of the perineal body including the anal sphincter complex without involvement of the anal canal or even the rectum.

4^th degree- injury to the perineum involving the anal sphincter complex with anal and rectal mucosa.

Prevention

Proper conduct in the 2^nd stage of labour taking due care of the perineum when it is likely to be damaged, in conditions as mentioned earlier in the chapter is the effective step to prevent undue laceration. The prevention of the perineal injuries in normal delivery has been outline.

Management

oRecent tear should be repaired immediately following the delivery of the placenta. This reduces the chance of infection and minimizes the blood loss. In cases of delay beyond 24 hours, the repair is to be withheld.

• Antibiotics should be started to prevent infection.
• The complete tear, should be repaired after 3 months if delayed beyond 24 hours.

Repair of complete perineal tear

Steps – 1: Put patient in lithotomy position. Antiseptic cleaning of the local area. Repair with local infiltration of 1% lignocaine hydrochloride 10-15 ml or with pudendal block or preferably under General anesthesia.

Steps –II: dissection is not required as in an old complete perineal tear.

a.The rectal and anal mucous is first sutured from above downwards. No 00 vicryl or PDS, atraumatic needle, interrupted stitches with knots inside the lumen is used.

b.The rectal muscles including the para-rectal fascia sutured by interrupted sutures using same suture material.

c.The torn ends of the sphincter ani externus are then exposed by Allies tissue forceps. The sphincter is then reconstructed with a figure of eight stitch, and it is supported by another layer of interrupted sutures. End to end sphincter approximation (not overlapping) is done.

Steps- III: repair of perineal muscle is done by interrupted sutures using No 0 PDS or dexons or chromic catgut

Steps-  IV: vaginal wall and the perineal skin are apposed by interrupted sutures

Suture material: polydioxanone suture (PDS) is preferred to catgut or polyglactin as it is associated with less infection and better long term function of the anal sphincter complex.

After care: repaired perineal injuries is similar to that following episiotomy.

Special care following repair of complete tear

1. A low residual diet consisting of milk, bread, egg, biscuits, fish, sweets etc. is given from 2^nd day onwards
2. Lactulose 8 ml twice daily beginning on the 2^nd  day and increasing the dose to 15 ml on the 3^rd  day is a satisfactory  regime to soften the stool.
3. Any one of the broad spectrum antibiotics is used during the intraoperative and the post- operative period. Metronidazole 400 mg thrice daily is to be continued for 5-7 days to cover the anaerobic contamination of the fetal matter.

Vagina

Isolated vaginal tears or lacerations without involvement of the perineum or cervix are not uncommon. These are usually seen following instrumental or manipulative delivery.  In such cases, the tears are extensive and often associated with brisk hemorrhage

Treatment

Tears associated with brisk hemorrhage, require exploration under GA with a good light. The tears are repaired by interrupted or continuous sutures using chromic catgut. No O. in case of extensive lacerations in addition to sutures, hemostasis may be achieved by intravaginal plugging by roller gauze, soaked with glycerine and acriflavine. The plug should be removed after 24 hours.

Colporrhexis: rupture of the vault of the vagina. It may be primary where only the vault is involved or secondary when associated with cervical tear (common). It is said to be complete when the peritoneum is opened up. Posterior fornix usually ruptures, however cervical tear is usually associated with tear of the lateral fornix. The tear may be traumatic or spontaneous specially in multiparae.

 Treatment

If the tear is limited to the vault including accessible part of the cervix, the repair is done from below. If however the cervix tear extends high up into the lower segment or major branches of uterine vessels are damaged, laparotomy is to be done simultaneously with resuscitative measures.

Cervix

Minor degree of cervical tear is invariable during 1^st delivery and requires no treatment. Extensive cervical tear is rare. It is the commonest cause of traumatic PPH. Left lateral tear is the commonest.

Causes

Iatrogenic– attempted forceps delivery or breech extraction through incompletely dilated cervix

Rigid cervix- may be congenital or more commonly scar from pervious operations on the cervix like amputation, presence of a lesion like carcinoma cervix

Strong uterine contractions- precipitate labour/extremely vascular cervix (placenta previa)

Detachment- cervix may be annular which involved the entire circumference of the cervix. This occurs following prolonged labour in primary cervical dystocia.

Diagnosis: excessive vaginal bleeding immediately following delivery in presence of a hard and contracted uterus.- raises the suspicion of a traumatic bleeding. Exploration of the uterovaginal canal under good light not only confirms the diagnosis but also helps to know the extent of the tear.

Dangers

Early

• Deep cervical tears involving the major vessels lead to severe PPH
• Broad ligament hematoma
• Pelvic cellulitis
• Thrombophlebitis

Late

• Ectropion
• Cervical incompetence with mid trimester abortion.

Treatment

Only deep cervical tear associated with bleeding should be repaired soon after delivery of the placenta. Repair should be done under GA in lithotomy position with a good light. The prerequisites are- Sims’ posterior vaginal speculum, vaginal wall retractors, at least two sponge holding forceps and an assistant.

Procedures

1. The anterior and posterior margins of the torn cervix are grasped by the sponge holding forceps. Instead of giving traction to the forceps, it is better to push down the fundus gently by the assistant. This makes the tear more accessible for effective suturing.
2. The apex is to be identified first and the first vertical mattress suture is placed just above the apex using a curved round bodied needle and chromic catgut taking whole thickness of the cervix.
3. The bleeding stops immediately.
4. The rest of the tear is repaired by similar mattress sutures. Mattress suture is preferable as it prevents rolling in the edges.
5. The cervical tears extending to the lower segment or vault with broad ligament hematoma, are managed as outlined in rupture uterus.

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