Introduction

A variety of bladder stones has been reported in women with previous hysterectomy or colposuspension [1, 2]. Though vesicovaginal fistula is not a rare complication of hysterectomy [3], primary vesical calculi are uncommon in women with vesicovaginal fistula and are associated with urinary contamination [4]. We report a rare case of iatrogenic bladder stone after hysterectomy and subsequent vesicovaginal fistula formation.

Case report

A 49-year-old, gravida 3, para 2 woman was referred to our urogynecology clinic because of frequency and urgency for the previous 2 years with unsuccessful anticholinergic drug treatment. She had had an abdominal hysterectomy because of a large uterine myoma 2 years previously, and intermittent small amounts of watery vaginal discharge developed 2 months after the operation. Her lower urinary tract symptoms had also been noted since that time.

Urinalysis was normal, and a urodynamic study showed a small maximum cystometric capacity. Cystoscopy disclosed a canary-yellow stone embedded in the bladder mucosa above the trigone, and a small hole was seen after we removed the stone (Fig. 1a). We performed vaginal ultrasound to evaluate the lower urinary tract and found a fistulous tract between the bladder wall and the upper vagina (Fig. 1b). The methylene blue test confirmed a patent vesicovaginal fistula. We performed a delayed Latzko procedure to repair the fistula, and the result was satisfactory.

Fig. 1
figure 1

a The bladder stone (arrow) embedded firmly in the bladder mucosa. b Vaginal ultrasound revealed a fistulous tract (arrow). (BL bladder, VVF vesicovaginal fistula, VAG vagina)

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Discussion

Both animal and clinical investigations have revealed that intravesical foreign bodies, including all suture materials and even olive oil, might become an origin of stone formation [5, 6], and vesical stones can even erode through the endopelvic fascia into the vagina and form a vesicovaginal fistula [7]. Based on our patient’s normal urinalysis, she had no urinary tract infection, and the etiology of the bladder stone was not similar to the case that Dalela et al. described [4]. In our patient, we considered that an inadvertent intravesical suture during hysterectomy had resulted in stone formation. Although the suture material was absorbed, the stone prevented the healing of the bladder mucosa and eroded through the bladder to the mucosa to form the vesicovaginal fistula.

Despite the fact that any intravesical suture could result in stone formation, we still suggest using quick-absorbable suture materials, such as chromic, during pelvic surgery, especially in the bladder base during hysterectomy to lower the risk of this complication. In patients with lower urinary tract symptoms after hysterectomy, cystoscopy is helpful in diagnosis, and vaginal ultrasound might detect overlooked lesions such as a second fistula or small stones. Once the fistula occurs, repair should be undertaken after resolving stone-induced edema and friability of the vesical wall [8].