title: Significant change or loss of intraoperative monitoring data: a 25-year experience in 12,375 spinal surgeries.
abstract: METHODS
  Retrospective.
  
  
  OBJECTIVE
  The purpose of this study was to report the spectrum of intraoperative events responsible for a loss or significant change in intraoperative monitoring (IOM) data.
  
  
  BACKGROUND
  The efficacy of spinal cord/nerve root monitoring is demonstrated in a large, single institution series of patients, involving all levels of the spinal column (occiput to sacrum) and all spinal surgical procedures.
  
  
  METHODS
  Multimodality IOM included somatosensory-evoked potentials, descending neurogenic-evoked potentials, neurogenic motor-evoked potentials, and spontaneous and triggered electromyography. A total of 12,375 patients who underwent surgery for spinal pathology between January 1985 and December 2010 were reviewed. There were 59.3% female patients (7178) and 40.7% male patients (5197). Procedures by spinal level were as follows: cervical 29.7% (3671), thoracic/thoracolumbar 45.4% (5624), and lumbosacral 24.9% (3080). Age at the time of surgery was as follows: older than 18 years, 72.7% (242/8993) and younger than 18 years, 27.3% (144/3382). A total of 77.8% (9633) patients underwent primary surgical procedures and 22.2% (2742) patients underwent revision surgical procedures.
  
  
  RESULTS
  A total of 406 instances of IOM data change/loss occurred in 386 of 12,375 (3.1%) patients. Causes for data degradation/loss included the following: instrumentation (n = 131), positioning (n = 85), correction (n = 56), systemic (n = 49), unknown (n = 24), and focal spinal cord compression (n = 15). Data loss/change was seen in revision (6.1%/167 patients) surgical procedures more commonly than in primary procedures (2.3%/219 patients; P < 0.0001). Data improvement was demonstrated by 88.7% (n = 360) after intervention versus 11.3% (n = 46) with no improvement in IOM data. One patient with improved data after intervention versus 14 with no improvement despite intervention had a permanent neurological deficit (P < 0.0001).
  
  
  CONCLUSIONS
  IOM data identified 386 (3.1%) patients with loss/degradation of data in 12,375 spinal surgical procedures. Fortunately, in 93.3% of patients, intervention led to data recovery and no neurological deficits. Reduction from a potential (worst-case scenario) 3.1% (386) of patients with significant change/loss of IOM data to a permanent neurological deficit rate of 0.12% (15) patients was achieved (P < 0.0001), thus confirming efficacy of IOM.
authors.affiliation: Barnes-Jewish Hospital, St. Louis, MO 63110, USA.
authors.forename: Barry L
authors.initials: BL
authors.lastname: Raynor
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Bright
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lenke
authors.forename: Raʼkerry K
authors.initials: RK
authors.lastname: Rahman
authors.forename: Keith H
authors.initials: KH
authors.lastname: Bridwell
authors.forename: K Daniel
authors.initials: KD
authors.lastname: Riew
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Buchowski
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Luhmann
authors.forename: Anne M
authors.initials: AM
authors.lastname: Padberg
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016247:Information Storage and Retrieval; D007431:Intraoperative Complications; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D019635:Neurosurgical Procedures; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D013116:Spinal Cord / Q000502:physiology / Q000601:surgery*; D013119:Spinal Cord Injuries / Q000517:prevention & control; D013122:Spinal Diseases / Q000503:physiopathology / Q000601:surgery*