[Bladder stone caused by olive oil following TVT operation].

Tension-free vaginal tape (TVT), a less-invasive variation of the suburethral sling, has been rapidly gaining popularity worldwide in the treatment of female stress urinary incontinence. We report on two cases of bladder stones composed of fatty acid calcium following TVT operations. Case 1: A 76-year-old woman with a history of hysterectomy due to cervical cancer was suffering from vault prolapse. The insertion of a ring pessary lead to the development of stress urinary incontinence, and she was referred to our hospital. As she was frail, sexually inactive, and elderly, she underwent partial colpocleisis (Le Fort operation) combined with a TVT operation. One-month postoperative videourodynamics and chain cystourethrography (CUG) using olive oil as the lubricant showed cure of incontinence and mild support of the urethra. Her maximum flow rate was 18.8 ml/s and no residual urine was observed. Six months postoperatively she developed postmiction pain and pyuria that were not improved by antibiotics. Cystoscopy showed a small bladder stone, whose removal cured cystitis. Case 2: A 49-year-old woman, with a history of abdominal hysterectomy due to myoma uteri, visited our hospital complaining of stress urinary incontinence. A periurethral collagen injection was only temporarily effective, and she underwent a TVT operation. A 1-month postoperative evaluation including chain CUG using olive oil as the lubricant showed cure of incontinence, mild support of the urethra, a maximum flow rate of 28.8 ml/s, and no residual urine. Two months postoperatively she developed miction pain and pyuria that were solved by removing a small bladder stone. Anti-incontinence surgery increases the risk of developing bladder stones due to either foreign bodies (bladder erosion) or obstruction. However, neither of our cases had these conditions; instead, both bladder stones were composed of fatty acid calcium that appeared to be related to the olive oil used as the lubricant in chain CUG. Only four cases (including ours) of bladder stones composed of fatty acid calcium have been documented, but they may indicate that care is necessary when using olive oil as a contrast medium or lubricant in the urinary tract. When a woman with a history of anti-incontinence surgery has persisting or recurrent cystitis, cystoscopy should be performed to exclude bladder erosion and stones.