A Novel Cystometric Model of Pelvic Floor Dysfunction After Rabbit Pelvic Floor Noxious Electrical Stimulation.

ABSTRACT

OBJECTIVES: Although a relationship between pelvic floor dysfunction and lower urinary tract symptoms is described in the literature, the mechanism and pathways need further characterization. We developed an animal model of pelvic floor dysfunction after noxious stimulation of the pubococcygeus (PC) muscle. METHODS: Fifteen female adult rabbits were evaluated with cystometry (CMG) and electromyography (EMG) recordings from the PC muscle. Cystometry/EMG was performed before and after treatment animal (n = 11) received noxious pelvic floor electrical stimulation through the PC EMG electrode, and controls (n = 4) underwent sham needle placement. Two animals underwent S3 dorsal rhizotomy to demonstrate that the observed results required afferent innervation. RESULTS: Voiding changes were demonstrated in 9 of 11 rabbits after stimulation. Most of the rabbits (7/9) exhibited a prolonged-dysfunctional voiding pattern with larger capacity (mean, 17 mL [SEM, ±8 mL]), longer intercontractile interval (227% [SEM, ±76%]) and duration (163% [SEM, ±20%]), and increased postvoid residual (24 mL [SEM, ±6 mL]). The remaining dysfunctional rabbits (2/9) exhibited an overactive-dysfunctional voiding pattern with lower capacity (-26 mL [SEM, ±6 mL]), shortened intercontractile interval (16% [SEM, ±9%]) and duration (56% [SEM, ±30%]), and decreased postvoid residual (-27 mL [SEM, ±6 mL]). Nonresponder rabbits (2/11) were relatively unchanged in their micturition cycles after stimulation. Rhizotomy animals were acontractile and filled until overflow incontinence occurred. CONCLUSIONS: Using noxious electrical stimulation of the pelvic musculature, we were able to produce an animal model of pelvic floor dysfunction in most rabbits as hallmarked by a larger bladder capacity, an increased intercontractile interval, and prolonged contraction duration.