Resecting and anastomosing gut, end-to-end anastomoses

When you do a laparotomy it will often be because you need to resect and anastomose a patient's gut. This is one of the most critical procedures you will have to undertake, and if you are inexperienced, one which will give you much anxiety. It is one of the few surgical methods which you can usefully practise before you operate on a living human patient. So go to the butcher's, get some animal gut, and practise anastomosing that. The penalty for failure will be peritonitis or a fistula.

Gut is most often anastomosed end-to-end, but there will be occasions when you will have to do it end-to-side, or side-to- side. You may also have to anastomose a patient's stomach to his small gut in a gastroenterostomy.

Don't be worried by the complexity of the methods which follow. The really important points are to: (1) Make sure that you start with two nice viable pink bleeding ends. (2) Get their serosal surfaces together. If you do this, they will soon unite. If only the mucosal surfaces touch one another they are less likely to unite, and more often leak. (3) Close the gut in two layers. You have got to be much more neat and accurate if you only use one. Don't worry about mucosa pouting out after the first layer, it can easily do this at the mesenteric border. Everted mucosa leaks. So if it everts as ''dog ears', push these back when you do the second layer. (3) Do the suturing outside the abdominal cavity on a towel. Contamination will then be less likely and clamps less important. (4) Wash the gut with tetracycline solution after you have done the anastomosis.

If you follow the four points above you won't go far wrong. Now for some of the others: Any sutures which go right through the wall of the gut (and so might leak) are usually infolded by a second layer of sutures which go through serosa and muscle only[md]these are called Lembert sutures. So close gut in two layers. Put the first layer through all its coats[md]this is the ''all-coats' layer. Make the Lembert sutures of the second layer bring the serosa of one loop into contact with the serosa of the other loop. Only put them through the peritoneum, the muscle, and the submucosa (the strongest layer of the gut), and don't go through the mucosa into the lumen of either loop.

You will need to hold the gut with stay sutures or clamps while you work on it. It is also desirable to hold it shut so that its contents don't leak out. Clamps do this best but you can use a tape. There are two kinds of clamp: non-crushing ones and crushing ones.

Non-crushing clamps, such as Lane's or Kocher's have thin, wide, flexible blades, and a ratchet with several teeth, so that you can adjust the way you close them to the thickness of the gut. Use non-crushing clamps to hold gut without injuring it; hold them between your fingers and ''milk' the gut contents away from the area you are working on. Apply only as many ''clicks of the ratchet' as you need to stop the contents of the gut from escaping, and blood from flowing from the cut ends.

Crushing clamps have narrower, stiffer blades, a ratchet with fewer teeth, and sometimes interlocking ridges on the blades to grip the gut more firmly. Crushing clamps prevent leaking completely. ''Milk' the contents of the gut away from the area to be crushed, and then apply a crushing clamp with its jaws protruding well beyond the edge of the gut, because gut widens as you crush it. Close the jaws tightly. Crushed gut dies, so cut the crushed gut away with the clamp. As you do this, be sure there is a non-crushing clamp nearby to stop the contents of the gut spilling out. Crushing clamps are thus always used with non-crushing ones. You can use crushing clamps in pairs or in sets of four as in Fig. 9-9.

You can use what we describe here as ''the closed method' or you can use ''the open method'. The closed method is usually done with clamps, but it can if necessary be done without them. The open method is usually done without clamps, but it can be done with them. Both the descriptions here assume you are doing an end-to-end anastomosis.

The ''closed method' with clamps is shown in Fig. 9-9 and is the standard one, because it causes the least contamination of the peritoneal cavity. You have first to join the back of the patient's gut (as it lies in front of you) and then the front. The important places for leaks are where the back and the front parts of the anastomosis join one another, at the mesenteric and the antemesenteric borders of the gut. If serosa of one loop is to be in contact with serosa of the other loop at these critical points, the gut here must be inverted. The stitch which does this best is the Connell stitch. You can use Connell stitches all along the front of the gut (A, in Fig, 9-6), but this is not the easiest way of stitching gut. You should however make three Connell stitches where leaks are most likely. Make the first one at the antemesenteric border where you start the anastomosis (B, in this figure). Make the second one at the mesenteric border, as you turn over the edge of the gut from suturing its back to suturing its front (C). Make the third one at the antemesenteric border again when you are about to complete the first layer (D).

The principle of the Connell stitch is that the catgut comes out into the mucosa and then goes back into it again, and it comes out of the serosa and goes back into the serosa again. It makes a ''loop on the mucosa'. It is this loop which makes the mucosa invert.

The ''open method' without clamps is shown in Fig. 9- 10. The important feature about this is less that it is open without clamps, than that it uses a single layer of mattress sutures (a second Lembert layer is optional, and this method can, if appropriate, be done with clamps). The open method is indicated: (1) In infants and small children, because all clamps crush their delicate gut to some extent. (2) If the two ends of the gut are of widely differing size, as when you need to join large and small gut end-to-end. (3) When you don't have any clamps. (4) When you cannot get clamps on to the gut, as when joining large gut to rectum after a Hartmann's procedure (10.10). The open method does however increase the risk of contaminating the peritoneal cavity. Pick up the gut in stay sutures. Use interrupted mattress sutures for the posterior layer (A, in Fig. 9-10) and continuous ones which pick up the mucosa in a second bite for the anterior layer (B, in this figure). These pick up a tiny bite of mucosa only after going through the whole gut wall. The last two stitches cannot be made too neatly, and have usually to go through all layers.

Some surgeons don't like this method. It is really a single layer method, which is not so safe. Even if you add a second Lembert layer, you cannot cannot continue this across the mesenteric border. Some say it is more difficult.

Which parts of the gut can you safely anastomose to which and when? (1) You can also safely anastomose small gut to small gut, and small gut to stomach. (2) You can safely anastomose the ileum to the colon, because it has a good blood supply, few bacteria, and its diameter matches that of the colon. Both these anastomoses are safe with obstructed gut. Anastomosing large gut to large gut is more dangerous, because it has a poorer blood supply and many bacteria. You cannot safely anastomose large gut to large gut when it is obstructed, and instead you have to let its contents escape through an ostomy (see Sections 9.6 and 32.27). When large gut is to be anastomosed, it has to be carefully prepared first with enemas and antibiotics, and even then it is safer if it is protected by a proximal colostomy.

Some other points. If you are not happy that you have made a satisfactory anastomosis (no anastomosis is ever quite ''watertight'), you can bring up a loop of omentum and stitch this loosely over the place which you think will leak. This is optional, and is not even desirable if you think an anastomosis is sound; but there are certain occasions when it is essential[md]notably the repair of a perforated peptic ulcer, as in Fig. 11-2.

Interrupted sutures use more suture material and take longer, so use continuous ones where you can: (1) In an adult you can use continuous or interrupted sutures for either layer, but, if you use non-absorbable sutures in an infant, they must be interrupted, because continuous sutures will not grow with him, and will eventually constrict his gut. (2) If the cut edges of the gut are not perfectly healthy, the patient very ill, and the risk of peritonitis great, use interrupted non-absorbable Lembert sutures.

In the small gut use whatever suture material you find convenient for either layer. In the stomach use catgut on an atraumatic needle for the first layer[md]if you use a non- absorbable suture material for this layer, it may be the site of ulcers later. Use whatever you find most convenient for the second (Lembert) layer[md]catgut, silk, cotton, or monofilament. In the large gut there may be an advantage in using non- absorbable sutures for all layers.

FORCEPS, intestinal, non-crushing, flexible blades, Kocher's, Doyen's or Lane's, 75 mm, two only. Use these to hold the gut while you anastomose it. Non-crushing clamps have been designed to exert the right pressure without being covered with rubber tubes. If you fit them with rubber, they may crush too tightly.

CLAMP, Payr's, intestinal crushing, lever action, medium size, 110 mm, two preferably four only. These are the standard crushing clamps.

CLAMP, Payr, intestinal crushing, lever action, small size for pylorus, 60 mm, two only.

THE ENDS TO BE JOINED MUST BE NICE AND PINK MINIMIZE CONTAMINATION Fig. 9-7 SOME GUT METHODS. If the gut that you want to anastomose end-to-end is unequal in size (A), you can make a nick in the antemesenteric border of the smaller piece (B), so that it enlarges (C). D, and E, the mattress sutures used for the posterior layer of the open method (A, in Fig. 9-10). After Turnbull RB. From a publication by Messrs Ethicon, permission requested.

METHODS FOR GUT TEN IMPORTANT POINTS. (1) Do the anastomosis on a towel outside the abdomen. (2) Don't contaminate the patient's peritoneal cavity; if you do, wash it out with tetracycline solution (1 g in 1000 ml of saline, 6.2). Be safe and wash any anastomosis with tetracycline solution when you have completed it. (3) Pick up gut with your fingers or Dennis Browne or Babcock's forceps, don't damage it with other forceps. (4) Cut the mesentery square with the gut, and don't undermine it. (5) Don't apply clamps so as to leave the antemesenteric border longer than the mesenteric one, or the tip of the loop will necrose (J, in Fig. 9-6). (6) Don't anastomose gut from which you have removed the mesentery (K, in that figure). (7) Don't occlude blood vessels when you suture the mesentery (L). (8) Don't use a crushing clamp when you should use a non-crushing one. If you do, you will leave crushed gut in the body (M)[md]excise it (N). (9) Don't use diathermy close to the gut: you may injure it so that it becomes nonviable. (10) If, when you have completed the anastomosis, the gut is not viable (''purplish'), resect its ends and start again!

THE CHOICE OF THE METHOD depends on the nature of the operation, your skill, and the equipment you have. Commonly, you will need to anastomose small gut end-to-end.

If the loops of gut are equal or only slightly unequal in size, you can use either method. If you use the closed one, apply the clamp on the smaller loop of gut obliquely, but without depriving a tongue of gut of its blood supply. Don't do what has been done in J, Fig. 9-6!

If the loops are very unequal in size (as when anastomosing small to large gut), you will have to use the open method of end-to-end anastomosis, and make a small cut in the antemesenteric border of the smaller loop, as in A, to C Fig. 9-7. Or, you can do an end-to-side or a side-to-side anastomosis.

Fig. 9-8 IS THE GUT VIABLE? A, it is viable if: (1) its surface is glistening, (2) its colour is pinkish, or only slightly blue, (3) it feels resilient like normal gut, (4) it contracts sluggishly (like a worm) when you pinch it, and (5) you can see pulsations in the vessels which run over the junction between it and its mesentery.

B, it is dead and not viable if: (1) it tends to dry out and its surface is no longer glistening, (2) it is greyish purple, or a dark purplish red (or even black), (3) it feels like blotting paper, (4) it does not contract when you pinch it, (5) the blood vessels over it are not pulsating or are filled with black clot.

C, if you are in doubt, remove the cause of the strangulation, apply a warm, moist pack to it, and wait 10 minutes. If it is viable, its colour will change from dusky to its normal pink.

IS HIS GUT VIABLE? [s7]TO RESECT, OR NOT TO RESECT? CAUTION ! For any method of anastomosis the gut must be viable, which also means that its blood supply must be good enough (see below).

Wait to decide if a patient's gut is viable or not until you have removed the cause[md]divided an obstructing band, or untwisted gut which has twisted on its mesentery. You can usually tell if gut is going to survive or not. Base your decision on several of these signs, not on one only.

Gut is viable if: (1) its surface is glistening, (2) its colour is pinkish, or only slightly blue, (3) it feels resilient like normal gut, (4) it contracts sluggishly (like a worm) when you pinch it, and (5) you can see pulsations in the vessels which run over the junction between it and its mesentery.

Gut is not viable if: (1) it tends to dry out and its surface is no longer glistening, (2) it is greyish purple, or a dark purplish red (or even black), (3) it feels like blotting paper, (4) it does not contract when you pinch it, (5) the blood vessels over it are not pulsating or are filled with black clot.

If you are in doubt, remove the cause of the strangulation, apply a warm, moist pack to it, and wait 10 minutes. If it is viable, its colour will change from dusky to its normal pink. If this happens it is alive, even if you cannot feel the pulsations of the mesenteric vessels. It may be alive if some areas remain purplish because of bruising. But if these areas are large, or do not improve in colour, consider all the discoloured gut nonviable.

If a piece of gut is obviously nonviable, resect it and do an end-to-end anastomosis.

If only part of the wall of the gut is nonviable, as with a Richter's hernia in Fig. 14-1, you may be able to invaginate it. If you are going to do this, the nonviable gut must: (1) not be perforated, (2) not extend over more than 30% of the circumference of the gut, (3) not extend to the mesenteric border, because suturing here may interfere with its blood supply, (4) be surrounded by a border of healthy gut. Use two layers of catgut to bring the serosal surfaces of the healthy margins together in the transverse axis, so as to invaginate the nonviable segment into the lumen of the gut where it can safely necrose (E, and F, 14-1). If it does not satisfy these criteria, resect it. One contributor considers that oversewing with Lembert sutures like this is more difficult and more dangerous than resecting the the damaged loop. If this is so, resect it.

If there is a completely encircling narrow band of greyish white necrosis, resect it and do an end-to-end anastomosis: it may turn into a stricture of the gut later (Garr[ac]e stricture).

If you release a loop of gut from a constriction ring, be especially careful. The loop of gut itself may be viable, but there may be a narrow band of necrosis at both the afferent and the efferent ends. It may slough at these narrow areas. Experts would resect the gut. But, if you are not expert at gut resection, oversewing the necrotic areas with Lembert sutures may be safer. If so, make a note of what you have found and done. A Garr[ac]e stricture may form, and the obstruction may recur.

IS THE BLOOD SUPPLY GOOD ENOUGH? If the mesenteric vessels of the gut you are going to anastomose are not pulsating, trim it back boldly until its edge bleeds with healthy red blood. If this does not happen immediately, try waiting a few minutes. If the flow is not pulsatile, it may become so if you wait a few minutes. Pick up the bleeding vessels with 4/0 chromic catgut, and don't rely on your anastomotic sutures to control bleeding.

PURSE STRING SUTURES A purse string suture is an invaginating suture around a circular opening, and is most often used to bury the stump of a patient's appendix.

Place a continuous Lembert suture through the serosa and muscle only, all round the appendix, as in F, Fig. 9-6. Tie the first hitch of a reef knot, pull the ends of the suture upwards, and push the stump of the appendix downwards. If necessary, ask your assistant to pull up the opposite side of the purse string as you do so. If you happen to penetrate all layers of the gut, reinforce the purse string with some more inverting sutures.

ENTEROTOMY An enterotomy is an opening in the gut. You may have to make one to make an ostomy (9.5), to inspect the gut to see where bleeding is coming from (11.3), or to remove Ascaris worms (10.6) or a foreign body (10.14).

Make an opening in the antemesenteric border of the gut and close it transversely in two layers as if you were anastomosing gut. In this way you will not narrow its lumen.

Fig. 9-9 END-TO-END ANASTOMOSIS BY THE ''CLOSED' METHOD. This method uses 4 crushing clamps. Clamps ''X' and ''Y' in Step B are optional, and it can be done without any clamps using stay sutures or tapes instead. The first pair of crushing clamps are removed with the loop of gut in Step E. The second pair are cut off in Step I. Non-crushing clamps are applied in Step B and remain on until Step N, although they are not shown after Step E. The critical parts of this anastomosis are the inverting Connell sutures in steps J, L, and N.

END-TO-END ANASTOMOSIS [s7]BY THE ''CLOSED' METHOD INDICATIONS. Anastomosing small gut, and large gut when there is not too much difference between the sizes of the lumen.

METHOD. This is the method in Figure 9-9. As shown it uses four crushing clamps and two non-crushing ones. You can readily leave out crushing clamps ''X' and ''Y' in B in this figure, and you can use no clamps at all.

Decide the length of gut you want to resect (A). Apply 4 crushing clamps in pairs close together at each end of the gut to be resected, and non-crushing ones on the gut to be anastomosed about 2 cm from the crushing ones (B).

If the mesentery is too thick for you to see the vessels clearly through it (as in the sigmoid colon, and the small gut mesentery in moderately fat patients, especially distally), divide the peritoneal layer nearest to you to outline the vessels (C).

Dissect the vessels one by one, pass a suture under each and tie it. Use 2/0 silk or chromic catgut on a mounted atraumatic needle (as shown in D), or an aneurysm needle, or a haemostat.

Divide the gut between each pair of crushing clamps (E).

(Note. From step F until step N each end of the gut is also held by a non-crushing clamp where this is convenient, although these are not always shown.)

Bring the crushing clamps together (F) and evert them (G).

Insert continuous Lembert sutures through the seromuscular coat of the posterior layer of the gut (the one which is furthest from you) starting at the antemesenteric border (H). Leave the ends long to act as stay sutures (I).

Cut the crushing clamps off by dividing the gut flush with them (I).

Start the all coats continuous inner layer at the antemesenteric border as a single all coats inverting Connell stitch (J). This is also shown in B, in Fig. 9-6. Use 2/0 chromic catgut. Continue as a simple over and over suture until you reach the mesenteric end K.

Insert the second all coats inverting Connell stitch on the mesenteric border (L) (also C, Fig. 9-6). Complete the anterior layer as simple over and over sutures (M) (or if you prefer as a continuous Connell suture A, Fig. 9-6). Insert the third Connell inverting stitch as you reach the antemesenteric end again (N) (also D, Fig. 9-6). Tie the two ends of the inner continuous suture together and cut them, leaving 5 mm ends. Now remove the non-crushing clamps.

Insert a continuous layer of Lembert sutures into the anterior seromuscular layer, starting at the mesenteric border and ending at the antemesenteric one. Tie each end to the free ends of the sutures that you have already inserted into the posterior layer and so complete the circle (O, and P). Test the patency of the lumen with your fingers (Q). Push some of the gut contents past the anastomosis to test for leaks. Close the defect in the mesentery with continuous 2/0 catgut or monofilament[md]taking great care not to occlude the vessels.

Fig. 9-10 THE END-TO-END ANASTOMOSIS OF UNEQUAL LOOPS OF GUT BY THE OPEN METHOD. Use this method if the ends of of the gut are of very unequal size, or if you don't have clamps. A, the interrupted mattress sutures of the posterior layer. B, the continuous sutures of the anterior layer, which take an extra bite of the mucosa. C, the gut occluded with an umbilical tape, the mesentery united and the ends of the gut held open with stay sutures. D, the first mattress sutures. E, more mattress sutures. F, a nick being made in the smaller loop of gut. G, insert some widely placed sutures to make sure that the circumferences of the two ends of the gut are exactly approximated. H, the final layer of Lembert sutures. After Turnbull RB. From a publication by Messrs Ethicon, permission requested.

END-TO-END ANASTOMOSIS [s7]BY THE OPEN METHOD INDICATIONS. (1) Anastomosing small gut to large gut. Or small gut to small gut when there is much difference between the sizes of the gut. (2) The absence of clamps. (3) Children.

METHOD. You can do this in two ways:

(1) You can follow Steps A to E and then J to R in Fig. 9-9, using stay sutures and tapes instead of clamps.

Or, (2) you can use the one-layer mattress suture method in Fig. 9-10. Pack off the peritoneal cavity. Prevent the gut contents from flooding into it by applying umbilical tapes around the gut. Cut the mesentery off square without undermining its cut ends. Apply stay sutures to open the ends of the gut.

To make the posterior layer use interrupted vertical through-and-through mattress sutures of 4/0 chromic catgut as in A, Fig. 9-10, and D, and E, Fig. 9-7.

To make the anterior layer, work from both sides towards the antemesenteric edge, and insert 4/0 chromic catgut sutures through all layers except the mucosa. Make a cut in the antemesenteric border of the smaller loop of gut. Don't trim the corners of the slit. Use continuous sutures which pick up the mucosa in a second bite for the anterior layer (B, Fig. 9-10). If the suture line is snug and inverted, stop at this stage. If not, complete the anastomosis with a final layer of Lembert 4/0 monofilament seromuscular sutures. You should be able to get most of the way round the gut, but you will not be able to suture its mesenteric border. This converts a one-layer method into a partial two-layer method.