Neurourology and Urodynamics 26:208^212 (2007) Increased Proximal Urethral Sensory Threshold After Radical Pelvic Surgery in Women Thomas M. Kessler, Urs E. Studer, and Fiona C. Burkhard* Department of Urology, University of Bern, Bern, Switzerland Aim: To identify factors that potentially in£uence urethral sensitivity in women. Patients and Methods: The current perception threshold was measured by double ring electrodes in the proximal and distal urethra in 120 women. Univariate analysis using Kaplan^Meier models and multivariate analysis applying Cox regressions were performed to identify factors in£uencing urethral sensitivity in women. Results: In univariate and multivariate analysis, women who had undergone radical pelvic surgery (radical cystectomy n ¼ 12, radical rectal surgery n ¼ 4) showed a signi¢cantly (log rank test P < 0.0001) increased proximal urethral sensory threshold compared to those without prior surgery (hazard ratio (HR) 4.17, 95% con¢dence interval (CI) 2.04^8.51), following vaginal hyster- ectomy (HR 4.95, 95% CI 2.07^11.85), abdominal hysterectomy (HR 5.96, 95% CI 2.68^13.23), or other non-pelvic surgery (HR 4.86, 95% CI 2.24^10.52). However, distal urethral sensitivity was una¡ected by any form of prior surgery. Also other variables assessed, including age, concomitant diseases, urodynamic diagnoses, functional urethral length, and maximum urethral closure pressure at rest had no in£uence on urethral sensitivity in univariate as well as in multivariate analysis. Conclusions: Increased proximal but una¡ected distal urethral sensory threshold after radical pel- vic surgery in women suggests that the a¡erent nerve ¢bers from the proximal urethra mainly pass through the pelvic plexus which is prone to damage during radical pelvic surgery, whereas the a¡er- ent innervation of the distal urethra is provided by the pudendal nerve. Better understanding the innervation of the proximal and distal urethra may help to improve surgical procedures, especially nerve sparing techniques. Neurourol. Urodynam. 26:208 ^212, 2007. ß 2006 Wiley-Liss, Inc. Key words: current perception threshold; lower urinary tract; radical pelvic surgery; urethral sensory threshold INTRODUCTION Lower urinary tract function depends on a complex neural circuit, which is still not completely understood. Animal data have shown that a¡erent neural pathways play an important role in regulating lower urinary tract function: Sensory nerve ¢bers in the urethral wall are activated by £uid £ow during voiding [Talaat, 1936; Todd, 1964; Le Feber et al., 1998], thus triggering a re£ex that augments ongoing bladder contractions [Barrington, 1931, 1941; Jung et al., 1999].This indicates that impaired urethral sensation contributes to lower urinary tract dysfunction. We hypothesize that various factors such as age, concomi- tant diseases, prior surgery, urodynamic diagnoses, and ure- thral pressure measurements may have an in£uence on urethral a¡erents. To test this hypothesis, the current percep- tion threshold of the proximal and distal urethra was deter- mined in women and compared regarding various factors potentially in£uencing urethral sensitivity. PATIENTS AND METHODS Patients The current perception threshold of the urethra was measured in 120 consecutive women referred for urodynamic evaluation for urinary tract symptoms. All patients were informed of the exact procedure and study purpose and gave informed consent. MeasurementTechnique Patients were placed in a dorsal lithotomy position. Before testing started, the bladder was emptied by a disposable cathe- ter in an aseptic technique. Urethral sensitivity was assessed by the mucosal electrosensitivity method as described by Kiesswetter [1977]. A double ring electrode was mounted just distal to the balloon on a12 French Foley catheter and inserted using lubricant without local anesthesia. The electrode was positioned in the proximal urethra by gently pulling the cathe- ter with the in£ated balloon backwards (Fig. 1A). Following TMK and FCB have a consultancy agreement with Medtronic, Inc. Abbreviations: HR, hazard ratio; CI, con¢dence interval; IQR, interquar- tile range Part of this work was presented as poster during the XIXth EAU congress in Vienna 2004 and was selected as the best poster presentation in the session ‘‘Poster session 35: Female urology, from bench to bedside.’’ *Correspondence to: Fiona C. Burkhard, MD, Department of Urology, Uni- versity of Bern, 3010 Bern, Switzerland. E-mail: ¢ona.burkhard@insel.ch Received 1 July 2005; Accepted 29 August 2006 Published online 9 November 2006 inWiley InterScience (www.interscience.wiley.com) DOI 10.1002/nau.20356 ß 2006Wiley-Liss,Inc.