title: Spinal cord stimulation in treatment of chronic benign pain: challenges in treatment planning and present status, a 22-year experience.
abstract: OBJECTIVE
  To present an in-depth analysis of clinical predictors of outcome including age, sex, etiology of pain, type of electrodes used, duration of pain, duration of treatment, development of tolerance, employment status, activities of daily living, psychological status, and quality of life. Suggestions for treatment of low back pain with a predominant axial component are addressed. We analyzed the complications and proposed remedial measures to improve the effectiveness of this modality.
  
  
  METHODS
  Study group consists of 410 patients (252 men, 58 women) with a mean age of 54 years and a mean follow-up period of 97.6 months. All patients were gated through a multidisciplinary pain clinic. The study was conducted over 22 years.
  
  
  RESULTS
  The early success rate was 80% (328 patients), whereas the long-term success rate of internalized patients was 74.1% (243 patients) after the mean follow-up period of 97.6 months. Hardware-related complications included displaced or fractured electrodes, infection, and hardware malfunction. Etiologies demonstrating efficacy included failed back syndrome, peripheral vascular disease, angina pain, complex regional pain syndrome I and II, peripheral neuropathy, lower limb pain caused by multiple sclerosis. Age, sex, laterality of pain or number of surgeries before implant did not play a role in predicting outcome. The percentage of pain relief was inversely related to the time interval between pain onset and time of implantation. Radicular pain with axial component responded better to dual Pisces electrode or Specify-Lead implantation.
  
  
  CONCLUSIONS
  Spinal cord stimulation can provide significant long-term pain relief with improved quality of life and employment. Results of this study will be effective in better defining prognostic factors and reducing complications leading to higher success rates with spinal cord stimulation.
authors.affiliation: Section of Neurosurgery, Department of Surgery, University of Saskatchewan, Regina General Hospital, Regina, Canada. krishna.kumar@rqhealth.ca
authors.forename: Krishna
authors.initials: K
authors.lastname: Kumar
authors.forename: Gary
authors.initials: G
authors.lastname: Hunter
authors.forename: Denny
authors.initials: D
authors.lastname: Demeria
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D004599:Electric Stimulation Therapy / Q000379:methods / Q000523:psychology / Q000639:trends*; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000453:epidemiology / Q000523:psychology; D059408:Pain Management; D010147:Pain Measurement / Q000523:psychology / Q000639:trends; D012189:Retrospective Studies; D013116:Spinal Cord / Q000502:physiology*; D016019:Survival Analysis; D016896:Treatment Outcome