Effect of Preoperative Single-dose Tamsulosin on Postoperative Urinary Retention After Mid-urethral Sling Placement: a Randomized, Double-blinded, Placebo-controlled Trial

Postoperative urinary retention has been defined as the inability to void despite having fluid in the bladder during the postoperative period. Urinary retention after pelvic reconstructive surgery requiring indwelling catheter or self-catheterization usage occurs in approximately 30-60% of patients postoperatively.

During a retro-fill voiding trial, the bladder is back-filled with a set amount of sterile water (often 300mL), the catheter is removed, the patient is permitted to void and the voided volume is compared with a bladder scan post void residual volume. "Passing" a voiding trial has previously been defined as voiding equal or greater than ⅔ the residual volume, whereas others characterize "passing" as voiding at least 200mL and voiding a greater volume than the post-void residual volume. If the patient does not "pass" the voiding trial, the patient is characterized as having postoperative urinary retention and is discharged home with an indwelling catheter to prevent detrusor injury from bladder over-distention, pain and urinary tract infection.

Many women consider being discharged home with a foley catheter to be a surgical complication and describe catheter use as the worst aspect of their surgery. Indwelling catheters are the leading cause of hospital-acquired urinary tract infections (UTIs), are often a source of embarrassment and inconvenience for patients, and often require additional office visits and healthcare utilization.

Tamsulosin is an alpha-adrenergic receptor blocker which is thought to increase smooth muscle relaxation and improve urinary flow. Current literature has been primarily focused on the effect of tamsulosin in men with benign prostatic hyperplasia, however may be beneficial in women as well with limited studies for postoperative urinary retention. Chapman, et al published a randomized control trial evaluating postoperative urinary retention after female pelvic reconstructive surgery. These patients underwent 10 days of tamsulosin (3 days preoperative and 7 days postoperative) and were found to have a 65% decrease in the urinary retention rate from 25.8% to 8.8%. Livne, et al published a study evaluating postoperative urinary retention decrease of 79.2% after postoperative administration of dibenzyline (an alpha-adrenergic receptor blocker) in women undergoing hysterectomy (post-operative urinary retention rate of 18.75% in controls and 3.9% in the treatment group). Additional studies have also been published evaluating postoperative urinary retention in men and women undergoing various surgeries and have demonstrated a decrease in postoperative urinary retention after tamsulosin administration from 72-88% compared with controls. These studies vary in tamsulosin administration from multiple days preoperative and postoperative to multiple doses preoperative and postoperative to a single postoperative dose, however no studies have been published in evaluating a single preoperative dose of tamsulosin and the effect on postoperative urinary retention. This has previously been studied as tamsulosin reaches a steady state in approximately 5 days, however when tamsulosin is given in a fasting patient, it can reach the maximum blood concentration in approximately 4-5 hours. As the majority of female pelvic reconstructive surgeries performed by our department are same-day surgeries, with patients being discharged the day of surgery, the investigators would like to investigate the effect of a single preoperative dose of tamsulosin on postoperative urinary retention and, by effect, home catheter usage after surgery. Tamsulosin is cost-effective at approximately $2 per tablet. Despite primarily being prescribed for benign prostatic hyperplasia, tamsulosin has been found to be a safe and well-tolerated treatment for voiding dysfunction in women.

Postoperative urinary retention is common after pelvic reconstructive surgery with mid-urethral sling placement and is extremely bothersome to patients. Tamsulosin is a low-risk, well tolerated, cost-effective medication that studies have suggested may decrease the rate of postoperative urinary retention. No study to date has evaluated preoperative administration of single- dose tamsulosin for postoperative urinary retention in a randomized placebo-controlled trial.