Botulinum toxin: An emerging therapy in female bladder outlet obstruction

We evaluated the utility of botulinum toxin in functional female bladder outlet obstruction.

A total of 7 consecutive female patients with bladder outlet obstruction were included. Patients with neurogenic bladder were excluded. All were previously treated with periodic dilations. Diagnosis was based on symptomatology, cystometry, and micturating cystograms. A total of 2 patients had been in chronic retention with residual volumes more than 400 ml. All were managed with an injection of botulinum toxin, 100 units in 2 ml of saline injected with a flexible cystoscopic needle. The site of the injection was deep submucosally, 0.5 ml in each quadrant at the level of the most prominent narrowing seen endoscopically. All the procedures were done as day care procedures under local anaesthesia. After the procedure, no catheter was placed. Patients were followed up for changes in IPSS scores and post void residual urine measurements. In all cases, multiple injections were used.

The follow-up period ranged from 48-52 weeks. The IPSS reduced by an average of 12 points. Post void residual urine reduced by 62%. Improvements commenced 4.85 days (average) after the procedure and lasted for an average of 16.8 weeks (range: 10.8-28 weeks).

There is a gradual improvement in symptoms over time and the maximal effect occurred at 10-14 days. The duration of improvement was approximately 16.8 weeks. All patients were satisfied by the degree of improvement felt.

Botulinum toxin proved successful in improving the voiding characteristics. It possibly acts at the zone of hypertonicity at the bladder neck or midurethra. The only disadvantage is the high cost of the drug.