Intradetrusor Botulinum toxin A (BTX-A) is a fourth-line treatment for management of interstitial cystitis (IC). Previous research describes intradetrusor BTX-A administration under general anesthesia using rigid cystoscopy. To our knowledge, there is no literature describing intradetrusor BTX-A administration using flexible cystoscopy in patients with IC. Our objective was to determine if intradetrusor BTX-A can be administered to patients with IC using flexible cystoscopy in an outpatient clinical setting with subjective improvement of patient symptoms.

A retrospective chart review was completed using patients from a private practice urology group diagnosed with IC, who had undergone intradetrusor BTX-A injection between 2015-2019. Of the 989 patients with the diagnosis code for IC, 21 had undergone BTX-A injection, and 18 met inclusion criteria. All patients included in the study had previously reported incomplete response to first, second, and third-line treatments for IC. Patient demographics are displayed in Table 1. Following informed consent, patients underwent intradetrusor BTX-A injection with flexible cystoscopy. This was done with either local anesthesia with transurethral instillation of lidocaine jelly or monitored anesthesia care (MAC). First-time injection consisted of 100 units of BTX-A administered in 20 injections, 1/2 cc per injection at 3 mm deep with a 27-gauge disposable needle. Injections were performed in an outpatient urology office by multiple urologists. The injection amount for subsequent treatments was determined by the urologist based on the patient’s previous response to 100 units. Additional treatments were determined based on the patient’s response to first injection. Timing interval between injections was based on patient’s return of symptoms. Primary endpoint was successful intradetrusor BTX-A administration using flexible cystoscopy with subjective patient-reported improvement of IC symptoms. Secondary endpoints included type of anesthesia, time interval between injections, and amount of BTX-A injected.

Of the patients diagnosed with interstitial cystitis, 18 underwent intradetrusor BTX-A administration via in-office flexible cystoscopy. 100% of patients were able to tolerate the procedure. MAC was used in 13 (72.2%) patients, while 5 (27.8%) were completed with local anesthesia (Figure 1.2). Of the 18 patients, 12 (66.7%, p=0.0010), reported symptom improvement following their first injection. Of the 18 patients, 15 (83.3%) underwent second injection with 78.6% improvement. Symptom improvement was based on patient-reported symptoms documented by the urologist. In the patient’s that underwent second injection, 11 (73.3%) continued at 100 units, three (20.0%) received 150 units, and one (6.7%) received 200 units. Improvement in IC symptoms was 80%, 66.7%, and 100%, respectively. 100% of the patients tolerated the second injection. Injection intervals were determined by patient’s return of subjective symptoms and request for repeat treatment.

Average time between first and second injection was 8.36 months. Of the 18 patients, 7 continued to receive 3 or more treatments. Of the 11 which discontinued treatment, three stopped after the first treatment and 5 after the second. Reasons for discontinuation included lack of efficacy in 4 (36%), urinary retention in 2 (18%), 2 (18%) were lost to follow-up, 1 (9%) with urinary tract infection, and 1 (9%) due to cost. (Table 2). Average follow-up was 27 +/- 22.5 months.

This study is the first to confirm intradetrusor BTX-A can be successfully administered in the outpatient setting using flexible cystoscopy in patients with IC and provide symptom improvement of their IC symptoms. This finding may be surprising, given that patients with IC can have increased sensitivity to bladder distention, which is required to adequately perform the procedure. The knowledge that IC patients can tolerate such a procedure without needing general anesthesia may lead to increased patient access to BTX-A injection, such as those who do not want general anesthesia or are too high-risk to receive general anesthesia. Patient comfort may be increased with MAC in those who cannot tolerate pure local anesthesia. There are many limitations of this study, which include the small sample size, lack of validated questionnaires, and retrospective nature. This small study provides a basis for continuing research on the subject. Further placebo controlled, randomized studies are needed to confirm the data.