title: Electrophysiologic monitoring for placement of laminectomy leads for spinal cord stimulation under general anesthesia.
abstract: OBJECTIVE
  Spinal cord stimulation (SCS) is a valid option for intractable neuropathic pain syndromes, yet some patients cannot undergo the standard awake procedure. Our retrospective study chronicles laminectomy-electrode placement for SCS under general anesthesia and use of compound muscle action potentials (CMAPs) to guide placement in the absence of patient verbal feedback.
  
  
  METHODS
  After nonsurgical measures proved ineffective for relief of neuropathic pain, 8 men and 11 women underwent SCS lead placement under general rather than local anesthesia because of deafness, language barriers, lidocaine allergy, or extensive scar tissue. A midline thoracic laminectomy was performed, and paddle SCS leads were placed. CMAPs of the rectus abdominis, quadriceps, gastrocnemius, anterior tibialis, abductor hallicus, and intercostal muscles were analyzed. Final lead placement was determined by the right-to-left symmetry of the CMAPs in conjunction with fluoroscopic imaging. Stimulation coverage was evaluated postoperatively.
  
  
  RESULTS
  Inconsistencies were found in lower-extremity CMAPs in the first two procedures. Thereafter, intercostal and rectus abdominis muscle CMAPs obtained in the remaining 17 procedures were consistent, more predictive of final results. Immediately postoperatively, 16 (84.2%) of 19 patients had adequate stimulation coverage and good pain relief with appropriate programming. Of three (15.8%) patients with minimal or no short-term pain relief, lack of response was not attributable to inadequate distribution of stimulation.
  
  
  CONCLUSIONS
  With electrophysiologic monitoring and fluoroscopy guidance, placement of SCS laminectomy leads in select patients under general anesthesia may result in appropriate stimulation coverage and pain relief in most.
authors.affiliation: Department of Neurosurgery, University of Cincinnati (UC) Neuroscience Institute and UC College of Medicine, Cincinnati, OH, USA.
authors.forename: Ellen L
authors.initials: EL
authors.lastname: Air
authors.forename: Greg R
authors.initials: GR
authors.lastname: Toczyl
authors.forename: George T
authors.initials: GT
authors.lastname: Mandybur
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General / Q000379:methods*; D004567:Electrodes, Implanted; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D018482:Muscle, Skeletal / Q000503:physiopathology; D009437:Neuralgia / Q000628:therapy*; D012189:Retrospective Studies; D013116:Spinal Cord / Q000502:physiology*; D062187:Spinal Cord Stimulation / Q000379:methods*