Ureteric calculus

A stone in the ureter nearly always has its birth in the kidney. Most are single small stones which pass spontaneously.

Clinical features

The presence of a stone passing down the ureter often causes intermittent attacks of ureteric colic.

Ureteric colic

A stone in the upper ureter produces symptoms identical with those of a stone blocking the pelviureteric junction. As the stone progresses to the lower ureter, the waves of agonising pain are typically referred more to the groin, external genitalia and the anterior surface of the thigh. In a man, the testis may be retracted by spasm of the cremaster and tenderness may persist for some days after the colic has ceased. When the stone is in the intramural ureter, the pain is referred to the tip of the penis. In both sexes there may be strangury.

Impaction

Most stones pass spontaneously from the ureter but there are five sites of anatomical narrowing where the stone may be arrested (Fig. 64.28). When the stone becomes impacted the attacks of colic give way to a more consistent dull pain, often felt in the iliac fossa. The pain is increased by exercise and lessened by rest. Distension of the renal pelvis due to obstruction may cause pain and discomfort in the loin. As time goes by the stone may become imbedded as the adjacent ureteric wall becomes eroded and oedematous due to pressure ischaemia. Perforation of the ureter and extravasation of urine is a rare complication.

Severe renal pain persisting for 1 or 2 days and then subsiding suggests that the ureter is completely obstructed by the stone. If urography (IVU) or ultrasonography suggests that obstruction persists after 1—2 weeks, the calculus should be removed because prolonged distension of the kidney will lead eventually to atrophy of the renal parenchyma.

Haematuria

Almost every attack of ureteric colic is associated with microscopic haematuria which lasts for a day or so. More profuse bleeding is uncommon and should raise the suspicion that the colic is due to passage of a clot.

Abdominal examination

There is tenderness and some rigidity over some part of the course of the ureter. The principal difficulty on the right side is to distinguish symptoms and signs of ureteric colic from those of acute appendicitis or acute cholecystitis. The pre­sence of haematuria does not rule out appendicitis, because an inflamed appendix lying near the ureter can give rise to a local ureteritis which will result in some red cells in the urine. In practice, the patient with acute renal colic is usually in greater pain and less systemically ill.

Imaging

Most urinary calculi are radiodense and visible on a plain abdominal radiograph. The stone may not be seen along the line of the ureter if it is very small or if it is obscured by contents of the gut or the shadows of nearby bones. An intravenous urogram performed while the patient has pain can confirm the diagnosis. During and for some time after an attack of renal colic there will probably be little or no excre­tion on the affected side. Occasionally, there is an extravasation of contrast from the dilated system. Late radiographs, taken up to 36 hours after the injection of contrast, may show dilatation of the ureter down to an obstructing calcu­lus. A radiolucent uric acid stone may be demonstrated as a filling defect in the contrast.

Analgesic abusers occasionally simulate symptoms to obtain drugs and the urogram is useful in excluding renal colic. If the urogram is normal during an attack, the patient does not have renal colic.

Cystoscopy is not indicated routinely but may reveal oedema and petechiae of the urothelium around the ureteric orifice when the stone is in the lower ureter. The stone may be visible in the orifice as it makes its passage into the bladder.

Retrograde ureterography is usually performed as an immediate preliminary to an endoscopic operation to remove a calculus but it may be of use if doubt remains after the intravenous urogram.

Treatment

Pain

Nonsteroidal anti-inflammatory drugs such as diclofenac and indomethacin have replaced opiates as the first line of treatment for renal colic. The value of smooth muscle relaxants such as propantheline (Pro-Banthine) is debateable.

Removal of the stone (Table 64.5)

Expectant treatment is appropriate for small stones that are likely to pass naturally. This may take many months and, as long as the patient is not disabled by recurrent attacks of colic, the progress of the stone can be followed by radiographs repeated every 6—8 weeks.

Endoscopic stone removal. Dormia basket. The use of wire baskets under image intensifier control has been replaced by ureteroscopic techniques, but may be useful when the necessary instruments and expertise are not available. There is a significant danger of ureteric injury, and basketry under radiographic control should only be used for small stones that are within 5 or 6 cm of the ureteric orifice (Fig. 64.29).

Ureteric meatotomy. Stones often lodge in the intramural part of the ureter. Careful endoscopic incision using a diathermy knife can enlarge the opening and free the stone. The procedure may lead to urinary reflux but it is rare for this to cause problems.

Ureteroscopic stone removal. A ureteroscope is a long endoscope which can be passed transurethrally across the bladder into the ureter (Fig. 64.30). The ureteroscope is used to remove stones which are impacted in the ureter. Stones that cannot be caught in baskets or endoscopic forceps under direct vision are fragmented using an electrohydraulic, percussive or laser lithotriptor.

Push bang. A stone that is lying in the middle or upper part of the ureter can often be flushed back into the kidney using a ureteric catheter. The repositioned calculus is ‘secured’ in the kidney by a J-stent. The patient can then be referred for ESWL

Lithotripsy in situ. Provided the stone is in a part of the ureter that can be identified by the imaging system of the lithotriptor, it can be fragmented in situ. This form of treat­ment is not appropriate if there is complete obstruction or if the stone has been impacted for a long time.

Open surgery

Ureterolithotomy. A radiograph should be taken to confirm the position of the stone immediately before surgery.

The incision must be appropriate for the position of the stone. Calculi in the upper third of the ureter are approached through a loin or upper quadrant transverse incision as used for a stone in the renal pelvis. Access to midureteric stones is through a muscle-cutting iliac fossa incision; lower ureteric stones are best reached through a Pfannenstiel incision.

For stones close to the bladder exposure is improved by ligating and dividing the superior vesicle vascular pedicle. The ureter is exposed in the retroperitoneum and slings are applied above and below the calculus to stop it from migrating from the operative field. The ureter is incised longitudinally, directly on to the stone, which is freed from adhesions by blunt dissection, and removed with stone forceps. Soft catheters are passed upwards and downwards to ensure that the ureter is clear. The ureterotomy is closed with interrupted absorbable sutures and a drain left in place for a day or so to drain urine leakage.

Idiopathic retroperitoneal fibrosis

This is a rare condition in which one or both ureters become bound up in a progressive fibrosis of the retroperitoneal tissues. The cause is unknown although some cases may be drug related. A similar clinical picture occurs in patients with leaking aortic aneurysm and infiltrating retroperitoneal malignancy.

The patient complains of backache which is unremitting for several months. The onset of anuria and renal failure prompts investigation of the renal tract which reveals hydronephrosis. The excretion urogram typically shows displacement of the obstructed ureters towards the midline and the appearances on CT are diagnostic. The sedimentation rate is markedly raised.

Treatment. It may be possible to insert ureteric stents as a temporary measure while renal function recovers. If not, percutaneous nephrostomies will allow the obstructed kidneys to drain. Some patients need renal replacement by dialysis. Some advocate that these patients should be treated conservatively with high-dose steroids. Surgical treatment involves careful dissection of the ureters from their entrapment (ureterolysis). Wrapping omentum around the freed ureters make recurrent obstruction less likely.