Urinary diversion via an ileal conduit is a frequently performed procedure following cystectomy. However, patients with ileal conduits are at an increased risk for developing urinary tract calculi. Nephrolithiasis develops in up to 12% of patients with ileal conduits and the overall incidence of stones after any urinary diversion approaches 32% when upper-tract calculi are included (1, 2). Potential contributing factors include metabolic disturbances, recurrent urinary tract infections, urinary stasis due to anatomical alterations, and the presence of foreign bodies within the conduit. We present a case of urinary stone formation within an ileal conduit, with the calculus developing around a migrated surgical staple.

An 81-year-old male with a history of invasive urothelial carcinoma underwent radical cystectomy with ileal conduit formation in 2020. He has been followed by nephrology since 2022 for chronic kidney disease, without known history of nephrolithiasis. The patient presented with a several-month history of flank pain, leading to the diagnosis of a urinary tract infection and initiation of empiric antibiotic therapy. During a subsequent nephrology evaluation, he brought two expelled urinary stones collected from the drainage bag.

Morphological examination of the calculi at our department, performed in accordance with established guidelines (3), revealed that both stones were classified as Type IVc, formed around a nucleus of surgical staples (Fig. 1). Further analysis using Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of struvite 80%, along with 20% sodium hydrogenurate.

Surgical staples are designed for permanent fixation, but in some cases, they may become dislodged or migrate due to tissue remodeling, local inflammation, or mechanical forces (4). In the setting of urinary diversions such as ileal conduits, this phenomenon can lead to unexpected and clinically significant complications. Migration of metallic clips or staples into the urinary tract—though rare—has been documented and may serve as a nidus for renal stone formation. Clinicians should maintain a high index of suspicion in post-cystectomy patients presenting with acute flank pain (5).

Surgical staples that become dislodged within ileal conduits can act as a core around which urinary stones form, accounting for approximately 86% of conduit calculi associated with foreign material (6). In some instances, these staples become completely encapsulated by stone material, making them undetectable on gross visual inspection. Recurrent urinary tract infections—particularly those involving urea-splitting bacteria—can further predispose patients to the formation of such calculi.

While stones under 3 cm pass spontaneously in approximately half of cases, larger or symptomatic calculi often require intervention. In patients with complex urinary diversions, antegrade ureterorenoscopy with laser lithotripsy is effective, especially when retrograde access is limited, and preserves the ureteroneovesical anastomosis (2, 7).

Management of this complication must extend beyond stone extraction. Comprehensive preventive strategies include aggressive hydration, correction of metabolic acidosis, routine conduit irrigation to minimize mucus accumulation, and targeted antibiotic prophylaxis for recurrent bacteriuria (1). Early identification and risk factor modification are key to reducing recurrence.

In our case, the first presentation of conduit stone occurred 48 months after diversion, falling within the reported range of 3 to 72 months. The stone was predominantly composed of struvite, indicating that its formation was driven by a urinary tract infection with urea-splitting bacteria. Notably, staple-associated stones have been shown to form earlier, with a mean latency of 22.5 months (6), emphasizing the need for early vigilance in this patient population.

Urinary stone formation in ileal conduits remains a clinically significant complication, often driven by a combination of metabolic derangements, chronic infection, and structural factors. This case underscores the potential for surgical staples to act as a nidus for struvite-based calculi, even several years after cystectomy. Clinicians managing patients with urinary diversions should maintain vigilance for signs of urolithiasis and consider the possibility of retained foreign bodies, particularly in the context of recurrent infections or spontaneous stone passage. Preventive strategies—including meticulous surgical technique, regular follow-up, infection control, and metabolic management—are essential to reducing the long-term burden of stone disease in this high-risk population.