Other sections in this chapter deal with obstruction to the outflow of urine down the urethra by strictures or enlargement of the prostate. Here we are concerned with the obstruction of his upper urinary tract: his ureters or the pelves of his kidneys. Because these are bilateral, his life is only in danger if both sides are obstructed simultaneously, or he has obstruction in a solitary kidney. When this happens he passes no urine and soon dies of uraemia, unless something is done quickly. Obstruction can be the result of: (1) Schistosoma haematobium causing strictures at the junctions of his ureters and his bladder, so producing hydronephroses. (2) Stones obstructing his renal pelves (or a staghorn calculus on one side, and no function on the other). (3) Mistakenly tying both a woman's ureters, while removing her uterus (22.12) or doing a Caesarean section (18.10).
A chronically obstructed kidney is usually large, so whenever you diagnose renal failure, always feel for enlarged kidneys. Permanent relief of the obstruction requires expert surgery, so you will have to refer the patient for this. Meanwhile, with luck, you may be able to keep a patient alive long enough to refer him (or her) to an expert, if you put a tube into one of the patient's obstructed ]]kidneys to decompress it, and remove the risk of uraemia. Chronic obstruction of this kind is not uncommon in areas where stones or S. haematobium are endemic.
Nephrostomy is not an easy operation, because the kidney is deep and difficult to get at. It is easier for schistosomal hydronephrosis of slow onset, than it is for stones, because the kidney is always large. Having exposed his kidney, you can either push a catheter through a dilated calyx, if you can find one, or you can open his renal pelvis and pull a catheter through his kidney into it. If a stone is the cause, and you can easily remove it, and his condition is good, consider doing so.
Fig. 23-17 NEPHROSTOMY TWO[md]DRAINING THE KIDNEY. G, to drain a kidney through its cortex, push a Malecot catheter into a tense fluctuant area. H, to drain a kidney through its pelvis, make a short incision in the posterior of the patient's renal pelvis, well away from its junction with his ureter. I, pass a probe through this incision out through the cortex of his kidney, and tie a Malecot catheter to it. J, the catheter in place. K, the wound closed with the nephrostomy tube in place.
NEPHROSTOMY If a patient has stones on both sides, decompress the side on which he has had recent pain or discomfort, because this is the side which is most likely to regain its function.
ANAESTHESIA. Give him a general anaesthetic, intubate him, and give him a relaxant (A 14.3).
POSITION. Place him on his side with the kidney to be operated on uppermost, as in B, Fig. 23-16. If your table has a kidney bridge, place his 12th rib on the underside over it. Then raise it, so as to open up the space between his rib cage and his pelvis. If you don't have a kidney bridge, place him on 3 or 4 sandbags or folded pillows. If you have a table that can be broken (the head or foot end can be lowered separately), use it to give you more room.
Flex his lower knee, straighten his upper knee, and put a pillow between them. Support his upper arm on a cushioned Mayo table, to prevent his trunk rotating. Take a wide strap, or a long piece of wide adhesive strapping, and wrap this round his pelvis and trochanters, so that his pelvis will not rotate. Have him leaning forwards a little, rather than strictly on his side.
INCISION. Here we assume that you are going to remove his 12th rib. You can, if you wish, approach his kidney just below and parallel to it, without excising it, especially when his kidney is large, as with a hydronephros. If necessary, make a short incision forwards from his 12th rib.
Mark his 12th rib with a felt pen, A, in Fig. 23-16. Then prepare and drape him, so as to leave an area about 20 cm wide over his 12th rib, from the midline of his back to his umbilicus.
Stand at his back, and make a skin incision starting at the lateral margin of his sacrospinalis. Cut along the line you have drawn over his 12th rib. Proceed anteriorly, and stop 5 cm short of his umbilicus, at the lateral margin of his rectus sheath. A shorter incision will do if he has a marked hydronephros.
You will have to cut much muscle. If possible, use a cutting diathermy, turned down low enough to cut through muscle and coagulate the vessels in it at the same time. Or, use a scalpel, and carefully control the bleeding points as you meet them.
Start by cutting his latissimus dorsi over his 12th rib, until you can see it (C). Then remove his 12th rib subperiosteally with a scalpel, or cutting diathermy. Cut the periosteum down the middle of his rib as far as its tip. Using a periosteal elevator, push the periosteum off its raw surface down its entire length. Reflect the flaps of periosteum. Take a curved periosteal stripper, and gently insert it under the distal part of the rib. Slide it up and down, until the rib is completely clear of periosteum (D, and E,). Cut the narrow strand of external oblique muscle attached to the tip of the rib. Use rib shears, or bone cutters, to cut off the rib as close to its neck as is convenient. Don't punch towards the neck of the rib, it is too close to his pleura! Smooth its stump so that it will not tear your gloves.
Cut the three muscles of his anterior abdominal wall in line with the skin incision. The first two, his external oblique and internal oblique, can be cut boldly. When you get down to his transversus, stop temporarily. His peritoneum is under it, and you don't want to risk opening it and flooding it with urine.
Return to the bed of his rib, and use the tip of a scalpel to cut its lowermost half. Carry the incision down on to the remaining fibres of his transversus muscle. Split this in the direction of its fibres.
You will now see his peritoneum, with his liver and part of his colon under it (F). Using a sponge on a holder, gently push the peritoneum down and away from you forwards and upwards. Use a self retaining retractor to separate his rib cage above, from the crest of his ilium below, and so open up the whole area.
Feel for his kidney up against his posterior abdominal wall. If you are not sure if it is his kidney, try moving it up and down. Use a scalpel to make a short incision in the fascia over it. Insert your fingers, separate his perirenal fat, which may be extensive if he is obese; and feel the shape, size, and consistency of his kidney. The tissues around it will probably be engorged and oedematous.
If his kidney is enlarged and soft and feels cystic, it is probably hydronephrotic, but it may be polycystic, in which case nephrostomy does not help. If it is hydronephrotic, it is probably safe to drain it through a dilated calyx, without exposing his renal pelvis (nephrostomy through the cortex).
If his kidney looks and feels fairly normal, expose its pelvis, and drain that (nephrostomy through the renal pelvis).
CAUTION ! (1) Be careful not to damage his fragile and often flattened renal vein, which enters his renal hilum anteriorly, and may cover part of his renal pelvis[md]which is why you should approach it from behind. (2) The end of the catheter must go into the drainage system, and not into the kidney itself.
NEPHROSTOMY THROUGH THE CORTEX is easier, but does not provide such good drainage. Choose an area on the convex surface of his kidney, where his renal parenchyma is thinly stretched over a tense fluctuant area, and which feels as if there is probably urine under pressure close below it. To confirm that you have found a dilated calyx or pelvis, aspirate it with a fine needle and syringe. Be sure that you are not dealing with an isolated renal cyst.
Take a fine haemostat and plunge this into the fluctuant area. If urine pours out, you are in the right place. Suck it out. Take a small Malecot catheter, flatten out its tip with a haemostat, and push this far enough into his kidney to get a good flow of urine (G, in Fig. 23-17). Remove the haemostat and leave the catheter in. If blood oozes around it, insert a haemostatic suture of fine plain catgut. Bring the nephrostomy tube to the surface.
NEPHROSTOMY THROUGH THE RENAL PELVIS drains a kidney better, but is more difficult, because you have to mobilize it. His renal pelvis lies posteriorly, so to get at it you have to turn his kidney forwards and medially, using finger dissection. When his perirenal tissues are oedematous and thickened, separating his kidney from the fat around it is not difficult. You will see his tense distended renal pelvis, which is the most posterior of the structures at the hilum.
Holding his kidney so as to expose his renal pelvis, confirm that urine is present by aspirating with a syringe and fine needle. Make a short incision in his renal pelvis, well away from its junction with his ureter. Urine should gush out (H).
Pass a curved probe through this incision. With your other hand, feel for an area on the convex surface of his kidney, where its cortex feels thin. Carefully (to minimize bleeding) push the tip of the probe out through this point (I). Tie the probe to a Malecot catheter, and draw it back and out through his kidney (J). Close the pyelostomy opening with two fine catgut sutures. If his kidney bleeds where the catheter emerges, apply a purse string catgut suture. Bring the catheter straight to the surface in a position in which he will not occlude it when he lies down (K).
If there is no area of thinned cortex, as may happen with a stone, consider removing the stone through an incision in his renal pelvis, and let the nephrostomy catheter drain from there.
Irrigate the tisses round his kidney, and close all the muscles over it together in one layer. Close his skin, and suture the nephrostomy tube to it. Finally, as an extra precaution, tape the nephrostomy tube to his skin. Connect it to a bedside collecting bottle.
If at any time you open his pleura, see Section 9.2D.
POSTOPERATIVELY, if urine drains freely, you have succeeded, and his uraemia should improve. Watch for the nephrostomy tube kinking or blocking. If it blocks, try irrigating it. He may develop a massive recovery diuresis, so make sure that he gets enough oral or parenteral fluid. See Section 23.5.
Refer him for definitive surgery, when his general condition permits.
Fig. 23-18 REMOVING A STONE FROM THE LOWER TWO-THIRDS OF THE URETER. A, centre the incision on McBurney's point; for the middle third carry it laterally in the line of the inguinal ligament, for the lower third carry it medially in the line of this ligament. Alternatively, for the lower third use a midline incision. B, divide the external oblique in the direction of its fibres. Cut the internal oblique muscle to expose the transversalis fascia. C, sweep the peritoneum medially to the bifurcation of the common iliac artery. Find the ureter and the stone. Pass catheters, or tapes, round the ureter above and below the stone. Cut on to it with a small knife. D, carefully remove it with Desjardin's forceps. E, pass a thin rubber catheter upwards and downwards to ensure patency. Kindly contributed by Samiran Nundy.