Introduction

The efficacy of percutaneous (PTNS) and transcutaneous tibial nerve stimulation (TTNS) in idiopathic overactive bladder (OAB) has been established in several studies. However, it may be difficult to perform these techniques in some cases. In such cases, medial plantar nerve (MPN) was identified as a new region for stimulation. Transcutaneous MPN stimulation (T-MPNS) is the electrostimulation of the lumbosacral roots that activate lumbosacral plexus, which controls the visceral organs and pelvic floor muscles, thereby improving bladder control. However, the exact mechanism of T-MPNS has not been studied.

Aim

To evaluate the efficacy of T-MPNS on quality of life (QoL) and clinical parameters associated with incontinence in women with idiopathic OAB.

Method

Study Design

• Prospective single-arm study

  Inclusion criteria

• Women over 18 years old with clinical diagnosis of idiopathic wet-OAB
• Intolerant or unresponsive to antimuscarinics or oral β3 adrenoreceptor agonist and discontinued after atleast 4 weeks

Treatment Strategy

• Cohort comprised 21 women who received T-MPNS
• Two self-adhesive surface electrodes were positioned with the negative electrode near the metatarsal-phalangeal joint of the great toe on the medial aspect of the foot and the positive electrode 2 cm inferior-posterior of the medial malleolus (in front of the medio-malleolar-calcaneal axis)
• T-MPNS sessions were performed twice a week, 30 minutes a day, for 6 weeks
• Women filled in details about voiding, incontinence, number of pads used and nocturia in 3-day bladder diary
• All the outcomes were measured at baseline and at 6 weeks after the treatment

Endpoints

• Improvement in incontinence episodes using 24-hr pad test (women with 50% or greater reduction in incontinence episodes were considered as positive responders)

• Symptom severity using the overactive bladder questionnaire (OAB-V8)
• Quality of life (QoL) using QoL-Incontinence Impact Questionnaire (IIQ-7)
• Cure-improvement rates
• Patient satisfaction

Results

• There were significant improvements in the severity of incontinence, frequency of voiding, incontinence episodes, nocturia, number of pads, symptom severity, and QoL parameters at the 6th week compared with baseline; p<0.001 for all as seen in Table 1

  Table 1. Comparison of endpoints at 6 weeks

  Endpoint

  Baseline

  At 6 weeks

  Severity of incontinence (pad test)

  55

  7

  Frequency

  12

  7

  Nocturia

  3

  1

  Incontinence episodes

  4

  1

  Number of pads

  3

  1

  OAB-V8

  28

  6

  IIQ-7

  11

  2

   

  *Values are presented as median

• Positive response rate and cure and improvement rates were very high (68.4% for both)
• About 73.7% reported that they were very satisfied/satisfied with the treatment

Conclusion

• Transcutaneous medial plantar nerve stimulation (T-MPNS) was defined for the first time as a new neuromodulation method in women with idiopathic overactive bladder.
• Significant improvement in clinical parameters and quality-of-life associated with incontinence was demonstrated with this technique.

Investig Clin Urol.  2023 Jul;64(4):395-403.