Overactive bladder (OAB) and its related symptoms as urinary frequency, urgency and urge incontinence are mostly due to detrusor overactivity and seem to be highly prevalent in the general population: it has been estimated that almost 11% of the population worldwide suffer from OAB, of which 49 million people only in Europe. OAB has a great impact on the quality of life, can lead to additional medical problems and represents a social and economic burden1. The first line of therapy is pharmacological; whenever patients with OAB do not respond or not tolerate oral therapy, intradetrusor injection of botulinum toxin A (BTX-A) may be considered as an effective treatment option, both for idiopathic and neurogenic OAB2. Although intradetrusor injection of BTX-A seems to be well tolerated, there is a lack of studies on patients’ satisfaction and on safety and efficacy of BTX-A injections performed in the urology clinic3. The aim of this study is to evaluate the safety and efficacy of this treatment in an office-based setting and performing a cost-benefit comparison with the same procedure administered in the operation theatre.

An observational and descriptive study was conducted on patients affected with dry or wet OAB of idiopathic or neurogenic origin who were undergoing intradetrusor injection of BTX-A in a single urology centre. All the patients enrolled had a previous urodynamic test which confirmed the diagnosis of DO; some of them had had previous BTX-A injections administered in the surgical setting. Pre-treatment evaluation included a complete medical history record and clinical examination, voiding diary, and a recent urine analysis and culture. Patients were counselled and signed the consent form. All patients filled an OAB-q SF form before the treatment and at 3 months follow up. In the clinic, patients underwent a intravesical instillation of local anaesthetic (Lidocaine hydrochloride 2% w/v 10 ml in 50 ml of saline) which stayed in place for 20 minutes and was then removed; in case of spinal cord injury patients with complete loss of bladder sensibility this step was not necessary. BTX-A was prepared diluting 100 UI in 10 ml of saline and then injected in every sector of the detrusor excluding the trigon during a video cystoscopy using a flexible scope. A different volume of BTX-A was administered basing on the OAB aetiology: 100 UI for idiopathic, 200 UI for neurogenic, 300 UI for not responder neurogenic OAB. After treatment, a clinical observation for 30-60 minutes was required and patients who do not perform intermittent catheterization (CIC) had to void. Follow ups were scheduled at 15 days, 3 and 6 months after the treatment: uroflowmetry and post-voiding residual volume (PVR) were performed. A simple numeric rating scale (from 0 to 10) was used to record patient’s satisfaction related to the procedure; data related for the same procedure in the operation theater were also collected, for patients who have previously undergone it. Type and grade of complications were recorded. Primary endpoints were patient’s satisfaction and rate of complications (haematuria, catheterization, urinary infections - UTI); secondary outcome was the clinical efficacy based on the OAB-q SF results. A comparative analysis of costs of the procedure in the office-based setting and in the theater was also performed. Statistical analysis using Student T-test and Chi-squared test were performed.

A total of 25 patients who underwent intradetrusor injections of BTX-A in an office setting were included. The average frequency ± DS of injection/patient was 1.8 ± 0.91; 11 patients underwent 1 single procedure, 10 patients had 2, and 4 patients had >2 sessions, with an average interval of 11.6 ± 6.01. Of this cohort, 8 patients have had previous BTX-A administrations in a surgical setting, whilst 17 patients were at their first BTX-A treatment. As day hospital or elective procedure, all 8 patients underwent at least a sedation and had a catheter inserted; in the office-based setting, 15/25 patients needed local anaesthetic instillation and only 3/25 needed a catheter afterwards. Table 1 reports the primary endpoints’ results comparing the data of the 8 patients who had the previous treatment in the theatre and the 17 who were treated in the specialist clinic: the NRS for the office-based procedure was significantly higher than for the operative setting (8.71 ± 1.05 vs. 6.87 ± 1.8, pvalue<0.025). The hospital staying (hours) was also significantly shorter (1.44 ± 0.73 vs 42 ± 21.27, respectively; pvalue 0.001) and the complications’ rate was lower. Regarding the secondary outcomes and treatment efficacy, the comparison between the two settings did not show any significant difference in terms of absolute OAB-q SF results before and after the injections, nor in terms of relative OAB-q SF reduction, as shown in Table 2. Considering that a single procedure costs, per patient, 700 € in the clinic, 1500 € in day surgery regimen and 2000 € in ordinary surgery, the administration of BTX-A in the specialist clinic allowed to save 800 € compared to the day surgery and up to 1300 € when compared to the ordinary regimen.

According to our data, intradetrusor injection of BTX-A performed in an ambulatory setting with or without local anaesthetic appears to be well tolerated by patients, who report higher rate of satisfaction compared to the same procedure in a surgical setting. The risk of intra- or post-procedural complications is low: the haematuria occurred in 56% of our patients, but it did not required catheterization in most of the cases; no admission were registered after this treatment, and the rate of UTI in the first 60 days after BTX was lower than in the operative setting, even though these data are difficult to interpret since many of the patients were performing CIC. The non-inferiority of the injection in the office-based vs. the theater-based setting was also confirmed by the OAB-q SF results analysis, and it is a fact that the ambulatory setting allows higher financial savings.

This study shows that the intradetrusor injections of BTX-A can be safely administered in an office-based setting and are well tolerated by patients. In terms of efficacy and costs, they are not inferior to the same procedure carried out in theater and permits strong financial savings, therefore they should be regarded as the best treatment option for not respondent OAB patients.

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Seze, M. De et al. Botulinum Toxin A ( Botox W ) Intradetrusor Injections in Adults with Neurogenic Detrusor Overactivity / Neurogenic Overactive Bladder?: A Systematic Literature Review. Eur. Urol. 53, 275–287 (2008).