Biomechanical comparison after in vitro laminar vertebral stabilization and vertebral body plating of the first and second lumbar vertebrae in specimens obtained from canine cadavers

OBJECTIVE: To compare biomechanical characteristics of vertebral segments after vertebral body plating or laminar stabilization following complete incision of the annulus fibrosus. SAMPLE: Vertebral segments from T13 through L3 obtained from 18 canine cadavers. PROCEDURES: A 4-point bending moment was applied in flexion and extension to the intact vertebral segments to determine a baseline range of motion (ROM) and neutral zone (NZ). Vertebral columns were then destabilized by creating a defect in the intervertebral disk via complete incision of the ventral aspect of the annulus fibrosus. The bending moment was applied again after stabilization was accomplished via vertebral body plating or with laminar stabilization (n = 9 vertebral segments/stabilization technique). The ROM and NZ were compared with their baseline values and among treatment groups. Finally, load-to-failure testing was performed in flexion. RESULTS: Mean relative ROM and NZ for segments treated with laminar stabilization were significantly lower than those for segments treated with vertebral plates. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of in vitro results suggested that laminar stabilization of vertebral segments provided greater stiffness than did vertebral body plating