title: Association between stimulation parameters and loss of efficacy of selective sacral nerve root stimulation.
abstract: OBJECTIVE
  This study sought to determine the association between stimulation parameters at the time of implantation and loss of efficacy on long-term follow-up.
  
  
  METHODS
  Between 2002 and 2007, 143 patients underwent selective sacral nerve root stimulation at our center as a treatment for voiding dysfunction. Nine patients were explanted because of loss of efficacy. The patients' charts were retrospectively reviewed and compared with those of a well-matched group of 12 positive responders. A t-test was used to determine the differences in voiding parameters and stimulation parameters between both groups (at p < 0.05).
  
  
  RESULTS
  The baseline amplitude levels in the loss of efficacy group were significantly higher than those of the control group (2.08 ± 0.35 V vs. 1.27 ± 0.25 V) (p= 0.008). The impedance levels were significantly higher in the loss of efficacy group than the control (1032.4 ± 181 Ω vs. 590 ± 44.6 Ω) (p= 0.025).
  
  
  CONCLUSIONS
  High stimulation parameters at the time of implantation were associated with loss of efficacy at the long-term follow-up.
authors: Surgery Department, Division of Urology, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Toronto, Ontario, Canada. yahia_ghaz@hotmail.com
authors: Yahya Q
authors: YQ
authors: Ghazwani
authors: Mohamed S
authors: MS
authors: Elkelini
authors: Magdy
authors: M
authors: Hassouna
mesh_terms: D000328:Adult; D000368:Aged; D004599:Electric Stimulation Therapy / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D004567:Electrodes, Implanted; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012447:Sacrum / Q000294:innervation*; D013126:Spinal Nerve Roots / Q000502:physiology*; D013997:Time Factors; D016896:Treatment Outcome; D014549:Urinary Incontinence / Q000628:therapy