Cystoscopy at the time of benign hysterectomy: a decision analysis

Gynecologists debate the optimal use for intraoperative cystoscopy at the time of benign hysterectomy. Although adding cystoscopy leads to additional up-front cost, it may also enable intraoperative detection of a urinary tract injury that may otherwise go unnoticed. Prompt injury detection and intraoperative repair decreases morbidity and is less costly than postoperative diagnosis and treatment. Because urinary tract injury is rare and not easily studied in a prospective fashion, decision analysis provides a method for evaluating the cost associated with varying strategies for use of cystoscopy.

The objective of the study was to quantify costs of routine cystoscopy, selective cystoscopy, or no cystoscopy with benign hysterectomy.

We created a decision analysis model using TreeAge Pro. Separate models evaluated cystoscopy following abdominal, laparoscopic/robotic, and vaginal hysterectomy from the perspective of a third-party payer. We modeled bladder and ureteral injuries detected intraoperatively and postoperatively. Ureteral injury detection included false-positive and false-negative results. Potential costs included diagnostics (imaging, repeat cystoscopy) and treatment (office/emergency room visits, readmission, ureteral stenting, cystotomy closure, ureteral reimplantation). Our model included costs of peritonitis, urinoma, and vesicovaginal/ureterovaginal fistula. Complication rates were determined from published literature. Costs were gathered from Medicare reimbursement as well as published literature when procedure codes could not accurately capture additional length of stay or work-up related to complications.

From prior studies, bladder injury incidence was 1.75%, 0.93%, and 2.91% for abdominal, laparoscopic/robotic, and vaginal hysterectomy, respectively. Ureteral injury incidence was 1.61%, 0.46%, and 0.46%, respectively. Hysterectomy costs without cystoscopy varied from $884.89 to $1121.91. Selective cystoscopy added $13.20-26.13 compared with no cystoscopy. Routine cystoscopy added $51.39-57.86 compared with selective cystoscopy. With the increasing risk of injury, selective cystoscopy becomes cost saving. When bladder injury exceeds 4.48-11.44% (based on surgical route) or ureteral injury exceeds 3.96-8.95%, selective cystoscopy costs less than no cystoscopy. Therefore, if surgeons estimate the risk of injury has exceeded these thresholds, cystoscopy may be cost saving. However, for routine cystoscopy to be cost saving, the risk of bladder injury would need to exceed 20.59-47.24% and ureteral injury 27.22-37.72%. Model robustness was checked with multiple 1-way sensitivity analyses, and no relevant thresholds for model variables other than injury rates were identified.

While routine cystoscopy increased the cost $64.59-83.99, selective cystoscopy had lower increases ($13.20-26.13). These costs are reduced/eliminated with increasing risk of injury. Even a modest increase in suspicion for injury should prompt selective cystoscopy with benign hysterectomy.