The Long-term Efficacy of Electrical Pudendal Nerve Stimulation for the Urgency-Frequency Syndrome in Women
Condition: Urgency-frequency Syndrome
MeSH terms: Urinary Bladder, Overactive; Syndrome
Study type: Observational

Summary: 
      The purpose of this study is to determine whether electrical pudendal nerve stimulation with
      acupuncture needles as electrodes has a good long-term therapeutic effect on the
      urgency-frequency syndrome in women.
    

Detailed description: 
      Urgency-frequency syndrome (UFS) is often refractory to pharmacotherapy. Electrical
      neuromodulation has proved to be valuable in this situation. The electrical neuromodulation
      therapies include transvaginal electrical stimulation (TES), percutaneous tibial nerve
      stimulation (PTNS), sacral nerve stimulation (SNS) and pudendal nerve stimulation (PNS).
      Their effects can be explained by modulation of reflex pathways at spinal and supraspinal
      levels.

      TES is easily applicable but it is sometimes intolerable for many patients due to discomfort,
      mucosal injury and high intensity stimulation for acceptable outcome. SNS differs from TES by
      its continuous stimulation and close nerve contact. It has a high rate of success, but
      symptoms appear to recur almost immediately after discontinuation of the stimulation and at
      least 20% of the patients initially tested do not respond to a test procedure. Its
      disadvantages included invasiveness of the procedure, the high cost of treatment, the high
      surgical revision rate, device replacement and adverse events. Because pudendal nerve (PN)
      afferents are particularly important for the inhibitory effect on the voiding reflex and SNS
      only excites part of PN afferents, direct PN stimulation may be more effective. PNS can be
      used to treat UFS refractory to SNS, but this therapy also has the disadvantages similar to
      those of SNS. PTNS is minimally invasive, demonstrates efficacy, and is easily applicable and
      well tolerated, but the results of chronic PTNS treatment are unknown in initially successful
      patients and PTNS effects diminish over time.

      By combining the advantages of PNS and PTNS and incorporating the technique of deep insertion
      of long acupuncture needles, we developed electrical pudendal nerve stimulation (EPNS). In
      EPNS, long acupuncture needles of 0.40 Х 100 or 125 mm were deeply inserted into four sacral
      points and electrified to stimulate the pudendal nerves. CT transverse plane at the coccygeal
      apex has showed that the position of the lower needle tip is similar to where (adjacent to PN
      at Alcock's canal) the Bion device is implanted for chronic PN stimulation. Besides the
      radiographic evidence, simultaneous records of perineal ultrasonographic PFM contraction,
      vaginal pressure and pelvic floor surface electromyogram in our previous study have proved
      that EPNS can exactly excite PN. Our previous study has also proved that EPNS has a good
      post-treatment effect on UFS in women. The purpose of the present study is to show the
      long-term efficacy of EPNS for UFS in women.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        female UFS patients with ≥50% symptom improvement at the end of EPNS treatment
      
Keywords: Electrical Pudendal Nerve Stimulation; Urgency-Frequency Syndrome; long-term efficacy