title: Continuous distraction-induced delayed spinal cord injury on motor-evoked potentials and histological changes of spinal cord in a porcine model.
abstract: METHODS
  Experimental study.
  
  
  OBJECTIVE
  This study evaluated distraction-induced delayed spinal cord injury in a porcine model.
  
  
  METHODS
  Department of Orthopedics, Korea University Guro Hospital, Seoul, Korea.
  
  
  METHODS
  Global osteotomy of three columns was performed on the thirteenth thoracic vertebrae with 13 pigs. The osteotomized vertebrae were distracted to 57-103% of segmental vertebral height (SVH) length, which was less than the distraction length that induces prompt SCI. The vertebral height was maintained until the loss of motor-evoked potential (MEP) signals with continuous distraction. The distraction distance and the time at which SCI occurred were measured, and distraction was then released to observe MEP recovery patterns.
  
  
  RESULTS
  We found delayed SCI in 8 of the 12 pigs, with a mean 20.9 mm (range 19-25 mm) and 10.7 min (range 8-12 min) of continuous spinal distraction, which was equivalent to 74.3% (68-84%) of SVH and 3.63% (3.42-4.31%) of thoracolumbar spinal length. A continuous 74.3% SVH distraction over an average of 10.7 min caused a delayed SCI, which was indicated by mild histologic changes in the spinal cord. Recovery patterns from SCI after distraction release were compatible with the degree of histological change; however, these patterns differed from the previously investigated prompt type of SCI.
  
  
  CONCLUSIONS
  Late onset injury due to continuous spinal distraction, which is comparable to iatrogenic SCI in spinal correction surgery, is important for understanding the impact of corrective surgery.
authors.affiliation: Division of Spinal Surgery, Department of Orthopedics, Korea University Ansan Hospital, Ansan, Korea.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Hong
authors.affiliation: Department of Orthopedics, Scoliosis Research Institute, Korea University Guro Hospital, Guro, Korea.
authors.forename: S-W
authors.initials: SW
authors.lastname: Suh
authors.affiliation: Department of Orthopedic Surgery, Spine Center, Kyung Hee University Hospital at Gangdong, School of Medicine, Seoul, Korea.
authors.forename: S-H
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Division of Spinal Surgery, Department of Orthopedics, Korea University Ansan Hospital, Ansan, Korea.
authors.forename: J-H
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Orthopedics, Spine Center, Korea University Anam Hospital, Anam, Korea.
authors.forename: S-Y
authors.initials: SY
authors.lastname: Park
authors.affiliation: Department of Anatomy, Korea University school of medicine, Seoul, Korea.
authors.forename: I J
authors.initials: IJ
authors.lastname: Rhyu
authors.affiliation: Department of Orthopedics, Scoliosis Research Institute, Korea University Guro Hospital, Guro, Korea.
authors.forename: J-H
authors.initials: JH
authors.lastname: Yang
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D019637:Orthopedic Procedures / Q000009:adverse effects*; D010027:Osteotomy / Q000009:adverse effects; D010812:Physical Stimulation; D013116:Spinal Cord / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000209:etiology* / Q000473:pathology*; D013552:Swine; D013904:Thoracic Vertebrae / Q000601:surgery; D014851:Wakefulness