A Case of a 4-cm Calculi Formed on Eroded Mersilene Cervical Cerclage Tape and Robotic-Assisted Laparoscopic Removal via Minimally Invasive Approach to Cystolithotomy

INTRODUCTION: Bladder calculi account for 5% of urinary calculi and 1.5% of urologic hospitalizations in the western world. The risk of bladder stone formation and the difficulty of its removal increases when a foreign body is present to act as a nidus for stone formation. Multiple cases of bladder stone formation have been reported following urogynecologic and gynecologic procedures, such as midurethral sling procedures, Burch colposuspension, and even cerclage placement. The true incidence of bladder stone formation following cerclage placement is not known; however, a systematic review of complications associated with transvaginal cerclage placement found that 1 out of 11 patients with fistula formation following cerclage placement developed a bladder stone. Stone formation tends to be a late complication of cerclage placement if it develops. Four case studies written between 2011 and 2025 on bladder stone formation on exposed cerclage suture within the bladder all describe delayed presentation between 3 and 10 years after cerclage placement. Open cystolithotomy has traditionally been the approach for removal of large bladder calculi. With the introduction of laparoscopic and robotic surgery, minimally invasive techniques have become alternative approaches. We present a case of a 59-year-old female with a history of cervical insufficiency and permanent Shirodkar cerclage placement in 2000 who was referred to our clinic for symptoms of vaginal pressure, deep pelvic burning, and urinary frequency that started in 2024 and were refractory to treatment with estradiol cream, phenazopyridine, and ibuprofen. Two previous urine cultures showed no growth of pathologic organisms. Pelvic ultrasound showed a large hyperechoic mass within the bladder cavity measuring 4.0 x 4.2 x 2.2 cm, and a subsequent in-office cystoscopy revealed a large, approximately 4 cm, bladder stone attached to Mersilene tape, which was suspected to have eroded into the bladder. The patient elected for surgical removal of the bladder stone and resection of the cerclage material. OBJECTIVE: The aim of this video is to demonstrate a minimally invasive surgical approach to the dissection and removal of a 4-cm calculus from eroded foreign body via cystotomy. METHODS: A minimally invasive robotic-assisted approach was chosen for cystotomy, dissection, and removal of the 4-cm calculus from the eroded foreign body. RESULTS: A 17.459-g calculus, measuring 4 cm in greatest dimension and composed of 100% carbonate apatite (Dahllite), was removed through a 4-cm cystotomy incision and a supraumbilical port site incision extended to 3cm in an Omega-shaped fashion. CONCLUSIONS: We conclude that robotic-assisted cystotomy can be considered a viable approach to the dissection and removal of bladder calculi despite erosion of foreign bodies into the bladder epithelium and large stone burden.Figure 1Figure 2