Temporal biomechanics of posterior cervical spine injuries in vivo in a rabbit model.
There are numerous clinical and biomechanical criteria for determination of acute spinal instability. No data, however, exist on the biomechanical behavior of the injured, untreated spine during the healing period. Using a rabbit model, this study was designed to quantify changes in the mechanical properties of the injured spine over time. Sixteen rabbits were assigned to four injury groups: Injury 1 (C4-5 supra/intraspinous ligament transection), Injury 2 (C4 laminectomy), or Injury 3 (C4 laminectomy, plus bilateral facet capsular ligament transection). The fourth injury group was Sham (posterior exposure of C4-5, no spinal injury). Preinjury range of motion was determined by standardized flexion-extension radiographs on all animals. Postinjury flexion-extension radiographs were taken at 4, 8, and 12 weeks. At the end of 12 weeks, animals were killed. Mean range of motion at C4-5 for all injury groups decreased from preinjury values. The greatest decrease was for the most severe injury. At 8 weeks, the range of motion for this injury was less than half of the preinjury level and increased to 62% of the preinjury level at 12 weeks.
Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut 06510.
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Wetzel
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Panjabi
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Pelker
D000818:Animals; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000293:injuries* / Q000503:physiopathology; D004195:Disease Models, Animal; D009068:Movement; D011817:Rabbits; D013997:Time Factors