Discussion
Patients with urgency incontinence often have an inadequate response to conservative (non-invasive) treatment, and poor adherence is common (7). Cystoscopic injection of botulinum toxin into the bladder wall could represent a viable alternative.
A total of 403 injections of botulinum toxin into the bladder wall were administered to 167 women during the study period. At the routine six-month follow-up, the women reported satisfaction with treatment after 76 % of injections and regained continence following 71 % of injections. This is consistent with international reports (1, 3, 4). One or more complications occurred after 20 % of injections.
Women with urgency incontinence are at increased risk of urinary tract infection (8), and the manufacturer of Botox® recommends antibiotic prophylaxis for the procedure (9). Most guidelines do not take a clear position on antibiotic prophylaxis (8), but it is commonly used in clinical practice (1). The actual benefit of antibiotic prophylaxis, as well as the choice of agent and treatment duration, remains a matter of discussion (1, 8), but a recent review supports the use of antibiotic prophylaxis (5). Our patients provide their general practitioner with a urine sample for culture two weeks before the procedure and any significant bacteriuria is treated preoperatively. In addition, all patients receive antibiotics starting the evening before the injection. Despite these measures, antibiotics were given for suspected or confirmed urinary tract infection following 12 % of injections.
Impaired bladder emptying after botulinum toxin treatment is an inherent risk since the purpose of the injections is to weaken the bladder musculature. In our study, catheterisation was required after 6 % of injections, ranging from once only to three months of catheterisation. Incomplete bladder emptying with residual urine can predispose to urinary tract infection, making postoperative follow-up important. Patients should be prepared for the possibility of postoperative voiding difficulties and the potential need for catheterisation. Urgency incontinence is a chronic condition, and repeated treatment may be necessary.
Limitations of the study are its retrospective design and reliance on data extracted as yes/no responses from unstructured medical records, largely based on self-reporting from patients of treatment effect and complications. Accordingly, the findings are associated with some uncertainty and should be interpreted with caution. Furthermore, the study was conducted at only one hospital and primarily reports results per treatment (n=403) rather than per patient (n=167). External validity may therefore be limited. Nevertheless, the treatment outcomes appear to be consistent with those reported to date in international literature.
Cystoscopic injection of botulinum toxin for urgency incontinence appears to be a useful alternative when conservative treatment has proved inadequate, although some complications must be expected.