Intradetrusor onabotulinumtoxinA (BTX) chemodenervation injection via cystoscopy is FDA approved for the third line treatment of overactive bladder. The office setting using intravesical lidocaine instillation avoids risk of anesthesia, reduces patient time burden, avoids operating room costs, and improves physician productivity. However, pain reported during BTX injection in the office setting has not been fully reported in the literature. Our aim was to compare patient reported pain without general anesthesia during cystoscopy with and without BTX injection in the office setting using a novel pain questionnaire.

IRB approval was obtained for investigating a prospective four question pain questionnaire, administered immediately following routine cystoscopy (CYS) with and without BTX injection from November 2018 to June 2019. All procedures were performed by a single physician and patients received lidocaine intravesical analgesia prior to instrumentation instilled for 5-10 minutes dwell time. Patients undergoing BTX injection received 10-20 injections in the posterior-lateral bladder wall with or without sparing of the trigone. Within 1 minute following completion of the procedure, patients were asked to fill out the questionnaire. Questions on this questionnaire (Figure 1) determined the following: (i) Degree of discomfort/pain on a 10 point Likert face grimace scale), (ii) The part of the procedure that was most, (iii) Need to terminate the procedure due to discomfort and (iv) If the patient would you be willing to undergo the same procedure again. Patient demographic, comorbidity and procedure characteristics were recorded. Data are presented for mean, standard deviation, and Student t-test.

There were 40 cystoscopy procedures with questionnaires completed during the study period. Patients who underwent cystoscopy with ureteral stent removal (n=4) or urethral dilation (n=1) were excluded from analysis. For the remaining 35 procedures, data is shown in Table 1. CYS was performed for hematuria in 16 (55%), obstructive symptoms in 6 (21%) and recurrent urinary tract infection in 7 (24%) patients. Six patients underwent BTX injections for refractory overactive bladder.

There was no difference in overall pain on the Likert scale, for both procedures the pain levels were mild. The portion of procedure which patients reported as the most uncomfortable during CYS was: cystoscope entry (51.7%); cystoscopic examination (13.8%); not relevant (34.5%). During BTX, entry of the cystoscope was most painful in one patient (16.7%), with 2 out of 10 pain reported on the Likert pain scale. The remaining patients (83.3%) reported that injection was the most painful part of the procedure. No procedures were stopped early due to discomfort. All patients in each group reported that if the procedure was beneficial, they would undergo the same procedure again.

There was no difference in pain scores for patients undergoing cystoscopy alone compared to cystoscopy with BTX injection and overall the pain was mild based on a Likert score of 2-3. This suggests that the pain of the procedure is primarily associated with insertion of the cystoscope even though the patients who had BTX did indicate that the injections were more painful than insertion off the cystoscope. This was a small pilot study and should be repeated with larger number of patients. The utility of the questionnaire shows promise so should be further validated.

Future research on pain during BTX injection should be directed at identifying pain during different sites of injection (trigone, posterior wall, lateral wall) as well as routes of injection comparing cystoscopic versus transvaginal routes of administration.