title: Intraoperative neurophysiologic detection of iatrogenic C5 nerve root injury during laminectomy for cervical compression myelopathy.
abstract: METHODS
  A retrospective and prospective study was conducted to investigate intraoperative neurophysiologic monitoring during cervical laminectomy to detect iatrogenic C5 nerve root palsy.
  
  
  OBJECTIVE
  To evaluate the usefulness of various intraoperative neuromonitoring methods for identifying C5 nerve root palsy.
  
  
  BACKGROUND
  One unsolved complication after laminectomy or laminoplasty for cervical compression myelopathy is C5 nerve root palsy. It can go undetected even in the presence of intraoperative neuromonitoring with conventional upper extremity mixed nerve or dermatomal somatosensory-evoked potentials or transcranial motor-evoked potentials, recording typically from hand muscles.
  
  
  METHODS
  The intraoperative neuromonitoring data of 200 patients who underwent cervical laminectomy for myelopathy between 1998 and 2000 were reviewed for C5 nerve root palsy. Retrospective studies were conducted for the first 132 patients, who were monitored with conventional techniques including ulnar and posterior tibial nerve somatosensory-evoked potentials, C5-C7 dermatomally evoked potentials, and transcranial electrical motor-evoked potentials recorded from hand and leg muscles. Prospective studies then were applied to the remaining 68 patients, for whom transcranial electrical motor-evoked potentials and spontaneous electromyography were monitored from deltoid and biceps muscles in the wake of undetected C5 nerve root palsy from conventional neurophysiologic monitoring methods.
  
  
  RESULTS
  In the retrospective cohort, six patients presented after surgery with C5 nerve root palsy showing unilateral deltoid muscle paralysis despite entirely unremarkable conventional somatosensory-evoked potentials, dermatomally evoked potentials, and transcranial electrical motor-evoked potentials from hand and leg muscles. For the prospective cohort, two patients experienced postoperative iatrogenic C5 motor nerve root palsy. Impending C5 nerve root injuries after laminectomy were successfully identified in both patients showing significant changes in deltoid and biceps transcranial electrical motor-evoked potentials and spontaneous electromyography, thereby averting more serious consequence. There were no false-negative and false-positive results.
  
  
  CONCLUSIONS
  In an effort to reduce postoperative C5 nerve root palsy, the clinician should consider intraoperative deltoid and biceps transcranial electrical motor-evoked potential and spontaneous electromyography monitoring whenever there is potential for iatrogenic C5 nerve root injury.
authors.affiliation: Surgical Monitoring Associates, Inc., Bala Cynwyd, Pennsylvania 19004, USA. fand@surgmon.com
authors.forename: Dapeng
authors.initials: D
authors.lastname: Fan
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Schwartz
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Vaccaro
authors.forename: Alan S
authors.initials: AS
authors.lastname: Hilibrand
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Albert
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D007049:Iatrogenic Disease / Q000517:prevention & control; D007796:Laminectomy / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D009333:Neck; D011183:Postoperative Complications / Q000517:prevention & control; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012189:Retrospective Studies; D013117:Spinal Cord Compression / Q000503:physiopathology* / Q000601:surgery; D013126:Spinal Nerve Roots / Q000293:injuries* / Q000502:physiology / Q000503:physiopathology; D013979:Tibial Nerve / Q000502:physiology / Q000503:physiopathology; D014459:Ulnar Nerve / Q000502:physiology / Q000503:physiopathology