Despite reviewing 39 eligible trials, few firm conclusions could be reached because of the multiple comparisons considered, the small size of individual trials, and their low quality. Whether or not to use a particular policy is usually a trade-off between the risks of morbidity (especially infection) and risks of recatheterisation.
A prospective, randomized trial comparing continuous bladder drainage with catheterization at abdominal hysterectomy.
To compare the infection rate and post-operative morbidity between in-dwelling urinary catheterization and 'in-out' catheterization at the time of routine total abdominal hysterectomy.
                The study comprised 100 patients who were blindly randomized to have either an indwelling Foley catheter or an 'in-out' catheterization at the time of surgery. Follow-up data on the retention of urine, urinary symptoms and infection were obtained.
                Of the 95 patients with complete data, 36% of those undergoing in-out catheterization had urinary retention after operation, requiring bladder emptying, compared with 4% of those receiving an indwelling catheter (P < 0.001). In addition, 29% of the catheterized group had urinary tract bacteriuria compared with 13% of the uncatheterized group (P < 0.025).
                This randomized controlled trial showed that in-out urinary catheterization at the time of routine abdominal hysterectomy was associated with a significantly higher incidence of post-operative urinary retention compared with in-dwelling catheterization, and may have implications for long-term bladder function.