title: Mechanism of action of sacral nerve stimulation using a transdermal amplitude-modulated signal in a spinal cord injury rodent model.
abstract: BACKGROUND
  : Sacral neuromodulation (SNM) is an effective treatment modality for several urological problems, including neurogenic bladder. However, the invasiveness of this technique makes it unsuitable for many patients. We present a novel transdermal amplitude-modulated signal (TAMS) that may provide a non-invasive alternative to implantable SNM to treat neurogenic detrusor overactivity (NDO).
  
  
  METHODS
  : In this study, we investigated the mechanism of action of non-invasive SNM using TAMS on our established spinal cord injury (SCI) animal model. We demonstrated that spinally transected rats develop urinary bladder hyper-reflexia after 3 weeks of SCI, indicated by the presence of uninhibited contractions, increased resting pressure, increased threshold pressure and increased maximum voiding pressure.
  
  
  RESULTS
  : Short-term neurostimulation affected urodynamics parameters by significantly reducing the threshold pressure (p = 0.02). Spinal transection also increased calcitonin gene-related protein (CGRP) concentration in the L6 dorsal root ganglia; whereas, neurostimulation significantly reduced CGRP concentration in L6 (p = 0.03).
  
  
  CONCLUSIONS
  : TAMS caused a reduction in NDO by inhibiting C-fibre activity.
authors.affiliation: Toronto Western Research Institute, Toronto, ON; Institute of Medical Science, University of Toronto and Department of Surgery, Division of Urology, University of Toronto, Toronto, ON.
authors.forename: Mohamed S
authors.initials: MS
authors.lastname: Elkelini
authors.forename: Igor
authors.initials: I
authors.lastname: Pravdivyi
authors.forename: Magdy M
authors.initials: MM
authors.lastname: Hassouna