Operating for a neonatal acute abdomen

Anastomosing neonatal gut is no easy task, but if you are surgically nimble, are well-experienced with adult gut, and have the right sutures and devoted nurses, you may succeed. You have one advantage[md]the contents of a neonate's gut are sterile, so that contamination of his abdominal cavity is less of a hazard than it is later on. Anaesthesia is a major problem, but you can use local anaesthesia, although the absence of relaxation does make the operation more difficult. Whatever the difficulties, you may be sure that if you cannot refer him, and don't operate, he will surely die.

An abdominal wound easily breaks down in an infant. It is least likely to do so if you make a transverse muscle-cutting incision. A muscle splitting paramedian incision is next best for healing, and gives good exposure. A child grows, so suture his gut and his wound with interrupted sutures to allow him to do so. Suture his fascia meticulously, with good bites on each side.

You will find that that distal end of an obstructed neonatal gut is so collapsed, and small, that an end-to-end anastomosis is difficult. So make an end-to-side or a side-to- side one. The disadvantage of doing this is that, later, the cul-de-sac that you make may become a refuge for bacteria, and cause the malabsorption syndrome, especially in the small gut. These anastomoses can however be revised later, if necessary.

NEONATAL ACUTE ABDOMENS ANAESTHESIA AND PREPARATION. See Section 28.1. If you cannot refer a child, operate at 24 hours, or as soon afterwards as possible.

INCISION. Make a right muscle-splitting paramedian, or supraumbilical transverse incision. Examine his whole gut, because there may be more than one obstruction.

DUODENAL ATRESIA takes various forms, including one in which the pancreas is all round the duodenum (annular pancreas, very rare). Anastomose the first part of his duodenum to the first loop of his jejunum behind his colon. If this is difficult, make the anastomosis in front of his colon. Do a side-to-side anastomosis in one ''all coats' layer, or in two layers with interrupted sutures. One of the difficulties is that you cannot see his pancreatic or bile ducts, and if you injure them he will certainly die. Bring up a loop of his proximal jejunum through his gastrocolic omentum, and anastomose it to his distended duodenum. Anastomosing collapsed jejunum is difficult.

JEJUNAL ATRESIA. You may find a variety of lesions, perhaps combined with malrotation, volvulus, meconium ileus, and meconium peritonitis (uncommon). Most often, there is a short segment, or segments, of atresia, or marked stenosis.

Anastomose his dilated jejunum above the stenosed segment to his collapsed jejunum below it. They will be very different in size, so do a side-to-side anastomosis. Unfortunately, a cul-de- sac will form, which will tend to grow.

Alternatively, if there is enough gut, resect the proximal loop to a point where it is about 1 to 1.5 cm in diameter. Cut it off at at 90[de], and the distal one at 45[de]. If there is still a difference in size, make a short incision in the antemesenteric border of the distal segment, as in F, Fig. 28- 2.

VOLVULUS OF THE MIDGUT. When you open his abdomen, you see distended coils of small gut, which may be cyanotic and congested, and obscure his right colon. Deliver his small gut to the surface, and protect it with warm moist packs. Examine the base of his mesentery to see which way it has twisted (usually anticlockwise). Untwist it, and hope that its normal colour will return. If it is viable, lay it back in place. If it is not viable, resect the gangrenous part, and anastomose viable gut. If you have to resect much gut, his outlook is poor. Before you close his abdomen make sure that: (1) there is no band of tissue obstructing his duodenum (band of Ladd, see below), and (2) his duodenum is patent. Do this by manipulating his stomach contents through into his small gut.

OBSTRUCTION BY BANDS (arrested rotation). If you find that his duodenum is obstructed by a band of tissue (band of Ladd) running from his caecum or ascending colon towards the right of his abdomen, this is the result of arrested rotation of his gut. These bands are often present but cause no problem.

If a band does appear to be causing obstruction, divide it. Divide the attachment of the band to his parietal peritoneum on the right side of the second part of his duodenum. Displace the right half of his colon to the left. If you see a second band extending from the midline to the start of his jejunum, divide that also. There may be a third band running from his ileum to his ascending colon. His caecum will now be free; leave it on the left side of his abdomen, and don't try to put it back it in its normal place.

OBSTRUCTION BY A REMNANT OF MECKEL'S DIVERTICULUM. Sometimes a cord of tissue runs from his ileum to his umbilicus, causing his gut to strangulate round it (28-4). If so, check its viability, resect it if it is strangulated, and remove the ''cord'.

ANASTOMOSING AN INFANT'S GUT [s7]see also Section 9.3 Use the finest haemostats, and handle his gut with the greatest care. Hold it with stay sutures, and don't use clamps[md]its contents are sterile, so contamination is unimportant. Tailor its ends so that their sizes are a little more equal (see above). If you cannot do this, make a side to side anastomosis. Use a catheter to suck the proximal end clear of any inspissated meconium that would otherwise block the anastomosis. Make a single layer of instrument-tied interrupted sutures, using atraumatic 3/0 chromic catgut, or, better, 4/0 polyglycolic acid (''Dexon'), or 5/0 silk. If you have none of these sutures, don't operate. In most situations there is no room for a second layer.

Gently invert the posterior wall of his gut, as you insert the first sutures. If you can do this satisfactorily, inverting the anterior wall should not be difficult. As you go round the corner from the posterior wall of the anastomosis, to the anterior one, continue to invert the sutures.

POSTOPERATIVELY, see also Section 28.1. Give him 80 to 100 ml/kg/day of fluid. Either give him 0.18% saline in 5% dextrose to which you have added 2 mmol/kg/day of potassium (A 15.1). Or, give him half-strength Darrow's solution in 2.5% dextrose, which will contain the necessary potassium. Replace clear gastric losses with 0.45% saline in 5% dextrose. Replace greenish gastric aspirate with 5% dextrose in Ringer's lactate.

Start oral feeding as soon as possible[md]when signs of bowel function return. Start with 5 ml of expressed breast milk 2-hourly, and increase this gradually as he tolerates it. This should be possible on the 2nd or 3rd day. Either give it by nasogastric tube, or better, through a tube passed down his gut beyond the anastomosis (making an enterostomy beyond the anastomosis is difficult, because his gut is so small).

DIFFICULTIES [s7]WITH NEONATAL GUT OBSTRUCTION If you find part of his TERMINAL ILEUM IS FILLED WITH THICK FLUID, and that distal to this is some putty-like material, and distal to that again, some meconium pellets just above his caecum, he has meconium ileus (rare). Emptying his gut operatively is difficult, and is not sufficiently rewarding to be described here.

If you find that his SMALL GUT IS DUPLICATED, anastomose the parallel parts to one another at either end.

If you find extensive GANGRENOUS GUT, he has: (1) a volvulus, or (2) twisting round a band or cord (see above), or (3) neonatal necrotizing enterocolitis (rare). Exteriorize the gangrenous part, and close his abdomen. His chances are poor.

Fig. 28-3 RAMSTEDT'S OPERATION for hypertrophic pyloric stenosis. A, waves of visible peristalsis passing across the abdomen. B, the wrinkled forehead and pitiable expression of a child with pyloric stenosis. C, the child anaesthetized in a Dennis Browne crucifix; use this for all neonatal operations. Note the nasogastric tube. Cover his chest loosely and expose his abdomen (not as shown). D, the thickened muscle of the pylorus, showing the site of the incision. E, intact mucosa pouting out of the incision. F, incising the pylorus. G, opening the incision in the muscle to reveal the mucosa. H, a longitudinal section of the pylorus. Partly after Harlow W, ''An Atlas of Surgery', (1958) Figs. 50 and 51, Heinemann Medical, with Kind permission.