title: The effect of pulse width and contact configuration on paresthesia coverage in spinal cord stimulation.
abstract: BACKGROUND
  In spinal cord stimulation for the management of chronic, intractable pain, a satisfactory analgesic effect can be obtained only when the stimulation-induced paresthesias cover all painful body areas completely or partially.
  
  
  OBJECTIVE
  To investigate the effect of stimulus pulse width (PW) and contact configuration (CC) on the area of paresthesia (PA), perception threshold (VPT), discomfort threshold (VDT), and usage range (UR) in spinal cord stimulation.
  
  
  METHODS
  Chronic pain patients were tested during a follow-up visit. They were stimulated monopolarly and with the CC giving each patient the best analgesia. VPT, VDT, and UR were determined for PWs of 90, 210, and 450 microseconds. The paresthesia contours at VDT were drawn on a body map and digitized; PA was calculated; and its anatomic composition was described. The effects of PW and CC on PA, VPT, VDT, and UR were tested statistically.
  
  
  RESULTS
  Twenty-four of 31 tests with low thoracic stimulation and 8 of 9 tests with cervical stimulation gave a significant extension of PA at increasing PW. In 14 of 18 tests (low thoracic), a caudal extension was obtained (primarily in L5-S2). In cervical stimulation the extension was predominantly caudal as well. In contrast to VPT and VDT, UR is not significantly different when stimulating with any CC.
  
  
  CONCLUSIONS
  PA extends caudally with increasing PW. The mechanism includes that the larger and smaller dorsal column fibers have a different mediolateral distribution and that smaller dorsal column fibers have a smaller UR and can be activated only when PW is sufficiently large. A similar effect of CC on PA is unlikely as long as electrodes with a large intercontact distance are applied.
authors.affiliation: Institute for Biomedical Technology, University of Twente, Enschede, The Netherlands. jan@holsheimer.nl
authors.forename: Jan
authors.initials: J
authors.lastname: Holsheimer
authors.forename: Jan R
authors.initials: JR
authors.lastname: Buitenweg
authors.forename: John
authors.initials: J
authors.lastname: Das
authors.forename: Paul
authors.initials: P
authors.lastname: de Sutter
authors.forename: Ljubomir
authors.initials: L
authors.lastname: Manola
authors.forename: Bart
authors.initials: B
authors.lastname: Nuttin
mesh_terms: D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D010292:Paresthesia / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D013116:Spinal Cord / Q000502:physiology*; D004561:Transcutaneous Electric Nerve Stimulation / Q000295:instrumentation / Q000379:methods*