FEMALE UROLOGY

Percutaneous tibial nerve stimulation in the treatment of overactive bladder: urodynamic data
Vandoninck V, van Balken MR, Agrò EF, Petta F, Micali F, Heesakkers JPFA, Debruyne FMJ, Kiemeney LALM, Bemelmans BLH
Department of Urology, University Medical Center Nijmegen, PO Box 9101, NL-6500 HB Nijmegen, The Netherlands
Neurourol Urodyn. 2004; 23: 246-51

• Aim: The aim of this study was to evaluate urodynamic changes after percutaneous tibial nerve stimulation (PTNS) for the treatment of complaints related to overactive bladder syndrome and to search for urodynamic-based predictive factors.
• Methods: Ninety consecutive patients with symptoms related to overactive bladder syndrome were enrolled in this study. Patients underwent 12 PTNS sessions. For evaluating objective success, the primary outcome measure was a reduction in number of urinary leakage episodes of 50% or more per 24 hours. Patients’ request for continuation of therapy was considered subjective success. This study focused on urodynamic features at baseline and on changes found after 12 PTNS treatments.
• Results: The objective success rate was 56% (leakages/24 hours). Subjective success rate was 64%. Frequency/volume chart data and quality of life scores improved significantly (P < 0.01). Pre- and posturodynamic data were available from 46 participants. Detrusor instabilities (DI) could be abolished in a few cases only. Increments in cystometric bladder capacity and in volume at DI were significant (P = 0.043 and 0.012, respectively). Subjects without detrusor instabilities at baseline were 1.7 times more prone to respond to PTNS (odds ratio, 1.75; 95% confidence interval [CI], 0.67-4.6). The more the bladder overactivity was pronounced, the less these patients were found to respond to PTNS, the area under the receiver operating curve was 0.644 (95% CI, 0.48-0.804).
• Conclusion: PTNS could not abolish DI. PTNS increased cystometric capacity and delayed the onset of DI. Cystometry seemed useful to select good candidates: patients without DI or with late DI onset proved to be the best candidates for PTNS.
  
  
• Editorial Comment
  The authors studied 90 patients with symptoms of OAB and performed 12 percutaneous tibial nerve stimulation (PTNS) on them. Their goal in obtaining objective success was a diminution of urinary leaking episodes by 50% or more per 24 hours. When available, the authors examined urodynamic features at baseline and after the course of therapy were completed. They found that patients without any evidence of detrusor overactivity had a 1.7 times more chance of responding to this therapy than patients with detrusor overactivity. In addition, the more pronounced the detrusor activity, the less chance of success would be obtained through this modality.
  Sacral nerve stimulation has now established itself as an option of therapy in patients with severe OAB, especially those who have failed pharmacologic therapy. Some urologists are somewhat reticent to become involved in sacral nerve stimulation secondary to the methods of preliminary testing or application of the technology. Into this niche, there may a position for PTNS. Percutaneous tibial nerve stimulation should be reviewed by all urologists for a potential addition for an office therapy, especially if they treat a significant number of patients with voiding dysfunction secondary to detrusor overactivity. The great value of this paper is both as an introduction to percutaneous nerve stimulation as well as helping to identify the sub-populations of patients with voiding dysfunction who this therapy may assist. Long term questions to be answered include its success in the different populations of male vs. female, detrusor activity and voiding dysfunction as well as the durability of the therapy after the multi week course of therapy has been completed. I advise all physicians who are interested in developing or introducing nerve stimulation in their practice to read this article and consider trying this therapy.

Dr. Steven P. Petrou
Associate Professor of Urology
Mayo Clinic College of Medicine
Jacksonville, Florida, USA