[Transcutaneous stimulation of the posterior tibial nerve modifies the sympathetic skin response and improves overactive bladder syndrome: Case series and possible diagnostic test]

Objective: (a) To assess the effect of transcutaneous neuromodulation (TNM) of the posterior tibial nerve plus biofeedback on the sympathetic skin response (SSR). (b) Evaluate its effect on clinical symptoms. (c) Consider SSR as a probable neurophysiological test useful both for diagnosis and for follow-up in patients with overactive bladder (OAB). (d) Evaluate its cost compared to other techniques.

Material and methods: A prospective quasi-experimental before and after study in 10 OAB patients.

Outcome variables: daytime (DUF) and nighttime (NUF) urinary frequency, strength of the pelvic floor muscles measured by manometry (maximum and mean pressure) and sympathetic skin response (SSR).

Results: DUF improved from 10.3±5.45 to 5.9±2.42 episodes (P=.0050). The NUF improved from 2.4±1.5 to 0.6±0.69 episodes (P=.0012). The maximum pressure ranged from 34.7±16.51 to 39.7±3.65mmHg (P=.0195). The mean pressure of the pelvic floor muscles improved from 6.6±3.65 to 9.3±5.43mmHg (P=.0333). SSR changed from 100% hyperexcitability prior to treatment to 50±14.14% (P=.0000).

Conclusion: TNM plus biofeedback could modify SSR and improve clinical and manometry variables in a series of patients with OAB. The probable diagnostic and prognostic utility of this neurophysiological test in OAB and detrusor hyperactivity is reported for the first time. A larger sample study is needed to confirm the promising findings seen in this preliminary study.