Chapter 10. The surgery of labour

Table of Contents
Obstetric anaesthesia
Delay in labour
Obstructed labour
Managing an obstructed labour
Vacuum extraction
Destructive operations
Which kind of Caesarean section?
Lower segment Caesarean section
Difficulties with Caesarean section
Classical Caesarean section
Extraperitoneal Caesarean section
Which is it to be? Elective section, ''trial of scar', or section early in labour?
Injuries of the birth canal
Old third-degree tears
Rupture of the uterus
Vesicovaginal fistulae (VVFs)
Rectovaginal fistulae (RVFs)

.1 The two worlds of obstetrics If labour does not proceed normally, you will have to intervene and help a mother. How best you should do this, and what methods you should use, depends greatly on where in the scale of advantage and disadvantage she is. This has been beautifully described by John Lawson:

[em]Obstetrically, there are now two worlds, with pockets of one world in the other, and every gradation between the two. In the advantaged industrial world Caesarean section is now so safe that it has done much to change the whole pattern of obstetrics there. In that world obstetric services are good, and theatres and blood banks well organised. If a mother needs a Caesarean section, it is done by a skilled obstetrician and an experienced anaesthetist. Antenatal care is available everywhere, transport is easy, and most mothers are sufficiently educated to understand why they should have a hospital delivery if they need one. Most of them only plan to have two or three children anyway, and are not frightened by the possibility that Caesarean section might reduce their chances of having any more. Just because it is so safe, it is used electively for between 5 and 10% of mothers as a means of anticipating difficulty, rather than dealing with disaster. It is done so efficiently that traumatic vaginal deliveries and perinatal deaths from birth injury have almost disappeared.

Most mothers in the developing world are less fortunate. A really disadvantaged one must have six or seven children, so that three or four will survive. If she has an obstructed labour in a distant village, she may arrive in your hospital after a long journey, dehydrated, ketotic, shocked, anaemic, or infected, or all of these things. If you have to do a Caesarean section, you may have to do it through infected tissues, so that it may be followed by peritonitis, which antibiotics may fail to control.

When she has recovered, she may remember only a frightening operation followed by a difficult puerperium, and deliberately not seek hospital care when she becomes pregnant again. If her baby died, she may blame the hospital for his death, and decide to have her next one at home. Unfortunately, Caesarean section seldom removes the factor which caused it, so that her narrow pelvis, which may have been the reason for her Caesarean section, is probably still there. But the scar in her uterus is now its weakest part, so that the chances of it rupturing are great. How can you help a mother like this? She may have no antenatal care in her next pregnancy, and be unable to reach hospital for her next delivery. How can obstetrics be adapted to her needs, without being dominated by the practice of the industrial world? One answer is to make good use of the alternatives to Caesarean section, and one of the main purposes of this chapter is to describe them.

Unfortunately, in many hospitals the methods used to assist a mother who is delayed or obstructed in labour are unnecessarly limited. If an oxytocin drip and a vacuum extractor fail, Caesarean section is automatic, and other possibilities are not considered. If her CPD (cephalopelvic disproportion) is mild, she can have a symphysiotomy (18.6, M 22.7). If her baby is dead, she can have a destructive operation (18.7).

An alternative, which is not practical, except in the hands of an expert obstetrician, is the standard type of mid-cavity rotational forceps, such as those of Kielland. In the hands of anyone else, these forceps are so dangerous that a mother and her baby will be safer if you do a Caesarean section, which you will have to learn to do anyway. So you will find that the only forceps mentioned here are Wrigley's pattern of outlet forceps (''low forceps', M 22.6). The only acceptable use of the standard mid-cavity forceps by non-experts is their application to the aftercoming head during a breech delivery. For this purpose outlet forceps can however usually be used instead.

Your first priority should be to see that, when a mother is admitted, she is examined by the most experienced person available. She must be carefully observed not less than four-hourly thereafter, and the observations that are made accurately recorded on her partogram. Unless this happens, the whole process of labour management breaks down.

The team will need guidelines to know when to call you. For the most part, they are the same as those for which a health centre refers her to hospital (M 18.11). Make sure you are called too often, rather than not often enough.

Besides the methods described here, you will also find the following useful: an oxytocin drip (M 22.2), vacuum extraction (M 22.3), symphysiotomy (M 22.7), and outlet forceps (M 22.6).

(1) When you start any operative delivery make sure that the midwife who is assisting you knows how to resuscitate the baby, and has the equipment ready for doing this (19.12). In some hospitals, the results of not doing so are seen only too tragically, in the numbers of handicapped children who attend their paediatric clinics. (2) Don't forget to relieve pain when you can, so make proper use of pethidine (M 18.15), pudendal blocks (18.1a), and trichloroethylene (A 11.7).

Lawson J. ''Embryotomy for obstructed labour'. Tropical Doctor. 1974;188[nd]91.

Obstetric anaesthesia

Anaesthesia is often the most dangerous part of a difficult delivery. In most district hospitals general anaesthesia is best avoided in obstetrics, except for Caesarean section, when the patient is bleeding, or is already hypovolaemic, or is very ill. It should be expert, and she must be intubated. It is dangerous in the circumstances of most labour wards, and the theatre may take dangerously long to get ready.

Most Caesarean sections can be done under subarachnoid (spinal) anaesthesia, provided you take the necessary precautions (A 16.6). You can also use local anaesthesia (A 6.9). For a vacuum extraction and outlet forceps, use a pudendal block, with local infiltration anaesthesia for the episiotomy. For a destructive operation, other than a transverse lie, use a pudendal block combined with intravenous pethidine and diazepam (A 8.8). For a transverse lie, she must have a general anaesthetic. For manual removal of the placenta, use intravenous pethidine and diazepam. Epidural anasthesia is excellent, but is probably impractical, except in specialized well-staffed obstetric units. The routine aseptic prcedures in your wards may not be reliable enough to justify its routine use, and you will probably not have the staff to monitor it.

LOCAL ANAESTHESIA [s7]FOR AN OPERATIVE VAGINAL DELIVERY Primary Anaesthesia describes transvaginal pudendal block, but not the alternative perineal pudendal block, nor any method of local infiltration. These are described here. Use a total of 50 ml of 0.5% lignocaine or 1% procaine, both with adrenalin (A 5-1).

Transvaginal pudendal block: see Section A 6.13.

Perineal pudendal block: raise a skin wheal half way between the patient's vaginal opening and her ischial tuberosities, as in C, Fig. 18-1. Use a 12 cm[mu]1 mm needle to reach her ischial spines. Inject about 12.5 ml of solution on each side.

Local infiltration anaesthesia is needed to supplement a pudendal block for most operative vaginal deliveries. For a low forceps delivery or episiotomy local infiltration alone may be enough. Keep the needle moving while you inject 25 ml of solution.

After a perineal pudendal block, use the same needle to puncture and infiltrate, as in D, 18-1. After a transvaginal one make fresh punctures.

For local infiltration alone, inject radially from a single central puncture site (E).

CAUTION ! (1) Premedicate her with pethidine and diazepam. (2) Distinguish her ischial spines from her ischial tuberosities. (3) ALWAYS withdraw the plunger before you inject. If you withdraw blood, move the needle, or you will inject the anaesthetic solution intravenously. (4) Give the anaesthetic enough time to act (at least 3 minutes).

Fig. 18-1 LOCAL ANAESTHESIA FOR AN OPERATIVE VAGINAL DELIVERY. A, feeling for a patient's ischial spine for a transvaginal pudendal block. B, injecting for a transvaginal pudendal block. C, the injection site for doing a pudendal block through her perineal skin. D, local anaesthesia after a pudendal block. E, local infiltration alone from a single central puncture site.

1, her ischial spine. 2, her ischial tuberosity. 3, the site of injection for pudendal block through her perineum and for local infiltration anaesthesia after a pudendal block. After Howie, Beryl. ''High Risk Obstetrics' Fig. 14-6 and 14-7. Macmillan Publishers, with kind permission.