A biomechanical, radiologic, and clinical comparison of outcome after multilevel cervical laminectomy or laminoplasty in the rabbit

Study Design. A rabbit model was used to compare clinical outcome, radiogra phic changes, and biomechanical flexibility after cervical laminectomy and open-door laminoplasty. Objective, This study tested the hypothesis that radiographic changes and b iomechanical flexibility could explain the differences in clinical outcome after cervical laminectomy and laminoplasty. Summary of Background Data. Although multilevel cervical laminoplasty is th ought to have advantages over cervical laminectomy, clinical outcome studie s have been contradictory, and no experimental study has examined the possi ble mechanisms for the differences after healing. Methods. Twenty-four New Zealand White rabbits were randomized into four gr oups: normal, sham, C3-C6 wide laminectomy, and C3-C6 open-door laminoplast y. Clinical, radiographic, and biomechanical data were collected and compar ed up to 3 months after surgery. Results. Laminectomy had a statistically significant poorer clinical outcom e when compared with laminoplasty after 3 months of healing. Radiologic ana lysis showed statistically significant angular deformity in the laminectomy group compared with laminoplasty and control groups at 3 months; in contra st, biomechanical measures of flexibility, neutral zone, and range of motio n showed only small differences between any of the groups at any time. Conclusions. The presence of deformity, and not a change in flexibility, is responsible for the differences in clinical outcome observed after laminec tomy compared with laminoplasty in this model.