Optimal Anesthesia for Polyacrylamide Hydrogel Injection: A Randomized Trial

Despite the popularity of urethral bulking with polyacrylamide hydrogel (PAHG) for stress urinary incontinence (SUI)/intrinsic sphincter deficiency (ISD), no studies have assessed optimal anesthetic protocols.

To compare pain scores between 2 anesthetic protocols in women undergoing in-office PAHG injection: (1) combined anesthetic [external lidocaine-plus-prilocaine (EMLA) cream, intraurethral lidocaine gel, and lidocaine periurethral block] or (2) topical-only (external EMLA cream and intraurethral lidocaine gel).

This single-blinded trial randomized women to 1 of 2 anesthetic protocols. The primary outcome was pain reported via a 10-point visual analog scale (VAS). Secondary outcomes included International Consultation on Incontinence Questionnaire-Urinary Incontinence (ICIQ-UI) and Patient Global Impression of Improvement (PGI-I) scores. A safety endpoint of 3 subjects in the topical-only arm requiring unplanned periurethral block to complete the PAHG procedure, and an a priori sample size of 52 subjects was set.

Recruitment stopped at 23 subjects (N=11 combined anesthetic vs. N=12 topical-only) upon meeting the safety endpoint. Mean procedural VAS pain scores were lower with concomitant periurethral block (4.5±2.7 combined anesthetic vs. 7.4±2.3 topical-only; P <0.01). For 3 subjects in the topical-only arm requiring additional anesthesia, VAS pain scores were reduced following periurethral block (10.0±0.0 preblock to 4.0±2.6 postblock; P =0.04). There was no difference between arms in procedure duration, reinjection, or questionnaire scores. Subjects in the combined anesthetic arm were less likely to require post-procedure straight catheterization (0% vs. 33% topical-only; P =0.04).

Use of a periurethral block with topical anesthetics reduced pain scores and improved postprocedure voiding. These findings support using a combined anesthetic protocol for women undergoing in-office PAHG injection.