1991, The British Journal of Radiology, 64, 467-469 Case reports

Metallic staples refluxing to the upper urinary tract: a source of renal calculi in patients with ileal conduit urinary diversion By P. McCarthy, MRCPI, FRCR, L Cheung, M D , *P. Hanno, M D and H. M. Pollack, M D Departments of Radiology and "Surgery Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA (Received June 1990) Keywords: Ileal conduit, Surgical staples, Calculus, Obstruction, Reflux Surgical stapling devices to close the proximal end of the isolated loop of an ileal urinary conduit have been used since the early 1970s (Assadnia et al, 1972). However, the occasional development of calculi forming around the metal staples has deterred uniform acceptance of this technique in spite of its advantages of speed and decreased post-operative morbidity (Assadnia et al, 1972; Bergman et al, 1978). We describe two patients who presented to this hospital in recent months, in whom surgical staples migrated proximally into the renal pelvis, becoming the nidus for stone formation in one of the patients. Case reports Case 1 A 62-year-old black woman with congenital syringomyelia had had a uretero-ileal diversion for neuropathic bladder 3 years previously. She presented for a routine follow-up intravenous urogram (IVU). Plain abdominal radiographs revealed several metallic surgical staples projected over the right renal outline. Plain tomography confirmed that the sutures were in the kidney (Fig. 1) and they were obscured by contrast during the subsequent IVU, confirming their location within the renal collecting system. The patient was asymptomatic and it was decided to manage her expectantly.

Case 2 A 65-year-old white woman had an ileal loop diversion after symptomatic failure of augmentation cystoplasty for severe interstitial cystitis. She had presented for a routine annual IVU 1 year previously and was discovered to have a single surgical staple probably in a left lower pole caylx. One year later, her plain abdominal radiograph showed a 1 cm calculus around a staple in the renal pelvis and the original lower pole staple had a suggestion of some calcification around it (Fig. 2). In addition, the kidney had shrunk in length from 11 cm to 8 cm and there was delay in the excretion of contrast agent (Fig. 3). The ureter had become markedly distended down to the level of the anastomosis. The larger stone was treated with extracorporeal shock wave lithotripsy (ESWL) and in spite of the narrowed uretero-ileal anastamosis, both the stone fragments and the staples passed satisfactorily. The staple in the lower pole calyx, however, remainded. Analysis of the stone fragments showed that they were primarily made up of triple phosphates. Again, the patient was asymptomatic with respect to the stones. A loopogram was not performed in either case. Address correspondence to Dr P. McCarthy. Vol. 64, No. 761

Figure 1. Case 1. A plain renal tomogram at 13 cm shows staple material to be clearly within the renal outline, which IVU showed to be in the collecting system.

Discussion It has long been known that contract of urine with non-absorbable suture material invites the possibility of stone formation in ileal conduits, as well as in other structures (Assadnia et al, 1972). Because of this some of the original users of stapling devices advised that the instruments had no place in urologic operations (Assadnia et al, 1972; Bergman et al, 1978). More recent evaluations have been more sanguine (Karamcheti et al, 1978; Brenner & Johnson, 1985), but most authors acknowledge an incidence of approximately 3-7% for 467

Case reports

Figure 2. Case 2. Plain film shows a 1 cm calculus around a staple in the left kidney and a small questionable area of calcification around the staple in the lower pole.

Figure 3. Case 2. IVU shows delayed excretion from a shrunken left kidney and the calculi lying in the lower renal pole, and in the region of the uretero-pelvic junction.

calculi forming within urinary conduits where metal staples have been used to close the proximal end of the loop (Brenner & Johnson, 1985). These stones usually form within the first two post-operative years (Brenner & Johnson, 1985). The risk of stone formation can be lessened, if not eliminated by excising the stapled proximal end of the loop and refashioning the anastomosis by hand (Heney et al, 1978; Myers et al, 1982). The recent availability of absorbable staples will probably also prove effective (Wheeless, 1984). Since most uretero-ileal anastomoses are freely refluxing (Koehler & Bowles, 1966) and in view of the well known ability of non-absorbable materials to migrate through tissues (Trevino et al, 1979) it is surprising that more reports of staples and staplerelated calculi in the upper urinary tracts of diverted patients have not appeared. One such case was recorded (Webster et al, 1987) but we are unaware of any others. Metallic staples used for gastrointestinal anastomoses are quite small and while they are radio-opaque, their diminutive nature makes it difficult to detect them when they are located out of their usual positions e.g. projected over the kidneys. Failure to recognize the staples or to appreciate that they are, in an aberrant

location probably accounts for the fact that other similar cases have not been reported; in all likelihood they are simply overlooked. Unfortunately even a tiny piece of metal can serve as a nidus for a urinary calculus or as a source for urinary tract infection. It is therefore important that radiologists be aware of the ability of ileal conduit sutures to reflux in to the upper urinary tract. A concerted search for such foreign bodies in diverted patients with persistent or recurrent urinary tract infection may well be rewarded by the disclosure of such minute, meandering foreign bodies, thus pinpointing the real cause of the symptoms, and perhaps preventing inappropriate diagnostic and therapeutic measures.


References ASSADNIA, A., LEE, O. N., PETRE, J. H. & LYONS, R. C , 1972.

Two cases of stone formation in ileal conduits after using staple gun for closure of proximal end of isolated loop. Journal of Urology, 108, 553. BERGMAN, S., SEARS, E. & JAVADPOUR, N., 1978. Complications

with mechanical stapling device in creation of ileoconduit. Urology, 12, 71-73. The British Journal of Radiology, May 1991

Metallic staples refluxing to the upper urinary tract: a source of renal calculi in patients with ileal conduit urinary diversion.

1991, The British Journal of Radiology, 64, 467-469 Case reports Metallic staples refluxing to the upper urinary tract: a source of renal calculi in...
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