title: Effects of pudendal neuromodulation on bladder function in chronic spinal cord-injured rats.
abstract: OBJECTIVE
  Few studies have investigated the feasibility of using pudendal neuromodulation to regulate bladder function in spinal cord-injured (SCI) animals. The present study aimed to determine the effects of electrical activation of the pudendal sensory branch on improving voiding functions in rats 6 weeks after a spinal cord injury and to explore the underlying neuromodulatory mechanisms.
  
  
  METHODS
  Two urodynamic measurements were used to assess the effects of electrical stimulation (ES) on bladder and urethral functions: simultaneous recordings of the intravesical pressure (IVP) during continuous isotonic transvesical infusion (i.e., isotonic IVP) and external urethral sphincter (EUS) electromyography (EUS-EMG), and simultaneous recordings of transvesical pressure under isovolumetric conditions (i.e., isovolumetric IVP) and urethral perfusion pressure (UPP).
  
  
  RESULTS
  Six weeks after the SCI, the rats showed voiding dysfunction, as indicated by abnormal cystometric measurements (e.g., increased volume threshold, increased contraction amplitude, and increased residual volume, and decreased voided volume). The voiding efficiency (VE) decreased to 13% after the SCI, but increased to 22-34% after applying pudendal afferent stimulation. In addition, pudendal stimulation significantly increased the EUS burst period and increased the difference between the UPP and the high-frequency oscillation (HFO) baselines, and changed the time offset between bladder and EUS activities. These findings suggest that pudendal afferent stimulation improved the VE by prolonging the micturition interval, decreased the urethral resistance, and recovered detrusor-sphincter dyssynergia during the voiding phase.
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of using pudendal neuromodulation in chronic SCI rats. These results could aid in developing an advanced neural prosthesis to restore bladder function in clinical settings.
authors.affiliation: Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei, Taiwan; Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.
authors.forename: Yin-Tsong
authors.initials: YT
authors.lastname: Lin
authors.affiliation: Graduate Institute of Neural Regenerative Medicine, Taipei Medical University, Taipei, Taiwan; Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Tsung-Hsun
authors.initials: TH
authors.lastname: Hsieh
authors.affiliation: Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Physical Medicine and Rehabilitation, Taipei Medical University Hospital, Taipei, Taiwan.
authors.forename: Shih-Ching
authors.initials: SC
authors.lastname: Chen
authors.affiliation: Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Physical Medicine and Rehabilitation, Taipei Medical University Hospital, Taipei, Taiwan.
authors.forename: Chien-Hung
authors.initials: CH
authors.lastname: Lai
authors.affiliation: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan; Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Te-Son
authors.initials: TS
authors.lastname: Kuo
authors.affiliation: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Chung-Ping
authors.initials: CP
authors.lastname: Chen
authors.affiliation: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan; Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Chii-Wann
authors.initials: CW
authors.lastname: Lin
authors.affiliation: Holistic Education Center, Mackay Medical College, New Taipei, Taiwan.
authors.forename: Shuenn-Tsong
authors.initials: ST
authors.lastname: Young
authors.affiliation: Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei, Taiwan; Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Physical Medicine and Rehabilitation, Taipei Medical University Hospital, Taipei, Taiwan; School of Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei, Taiwan. Electronic address: cwpeng@tmu.edu.tw.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Peng
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004599:Electric Stimulation Therapy; D004576:Electromyography; D005260:Female; D060525:Pudendal Nerve / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000150:complications*; D014521:Urethra / Q000473:pathology*; D014554:Urination; D014555:Urination Disorders / Q000628:therapy*; D014563:Urodynamics
keywords: electrical stimulation; intravesical pressure; pudendal nerve; spinal cord injury; voiding efficiency