title: Pulse width programming in spinal cord stimulation: a clinical study.
abstract: BACKGROUND
  With advances in spinal cord stimulation (SCS) technology, particularly rechargeable implantable, patients are now being offered a wider range of parameters to treat their pain. In particular, pulse width (PW) programming ranges of rechargeable implantable pulse generators now match that of radiofrequency systems (with programmability up to 1000 microseconds. The intent of the present study was to investigate the effects of varying PW in SCS.
  
  
  OBJECTIVE
  To understand the effects of PW programming in spinal cord stimulation (SCS).
  
  
  METHODS
  Single-center, prospective, randomized, single-blind evaluation of the technical and clinical outcomes of PW programming.
  
  
  METHODS
  Acute, outpatient follow-up.
  
  
  METHODS
  Subjects using fully-implanted SCS for > 3 months to treat chronic intractable low back and/or leg pain. Programming of a wide range (50-1000 microseconds) of programmed PW settings using each patient's otherwise unchanged 'walk-in' program.
  
  
  METHODS
  Paresthesia thresholds (perception, maximum comfortable, discomfort), paresthesia coverage and patient choice of tested programs.
  
  
  RESULTS
  We found strength-duration parameters of chronaxie and rheobase to be 295 (242 - 326) microseconds and 2.5 (1.3 - 3.3) mA, respectively. The median PW of all patients' 'walk-out' programs was 400 microseconds, approximately 48% higher than median chronaxie (p = 0.01), suggesting that chronaxie may not relate to patient-preferred stimulation settings. We found that 7/19 patients selected new PW programs, which significantly increased their paresthesia-pain overlap by 56% on average (p = 0.047). We estimated that 10/19 patients appeared to have greater paresthesia coverage, and 8/19 patients appeared to display a 'caudal shift' of paresthesia coverage with increased PW.
  
  
  CONCLUSIONS
  Small number of patients.
  
  
  CONCLUSIONS
  Variable PW programming in SCS appears to have clinical value, demonstrated by some patients improving their paresthesia-pain overlap, as well as the ability to increase and even 'steer' paresthesia coverage.
authors.affiliation: Comprehensive Pain and Rehabilitation, Pascagoula, MS 39581, USA. nopaindr@mac.com
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Yearwood
authors.forename: Brad
authors.initials: B
authors.lastname: Hershey
authors.forename: Kerry
authors.initials: K
authors.lastname: Bradley
authors.forename: Dongchul
authors.initials: D
authors.lastname: Lee
mesh_terms: D004599:Electric Stimulation Therapy / Q000009:adverse effects / Q000379:methods*; D004567:Electrodes, Implanted / Q000592:standards; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D010147:Pain Measurement / Q000379:methods; D010292:Paresthesia / Q000209:etiology / Q000517:prevention & control; D011446:Prospective Studies; D019919:Prosthesis Implantation / Q000295:instrumentation / Q000379:methods*; D012585:Sciatica / Q000628:therapy*; D016037:Single-Blind Method; D012984:Software / Q000592:standards; D013116:Spinal Cord / Q000601:surgery*; D016896:Treatment Outcome