A METHOD FOR SHORTENING OF THE RAT SPINE AND ITS NEUROLOGIC CONSEQUENCES

Large laboratory animals are the usual choice for complex surgical pro cedures on the spine and spinal cord, such as shortening of the spine. It would, however, be advantageous to be able to use a small inexpens ive mammal like the rat. We describe a procedure which allows thoracic spondylectomy (T8-T9) to be performed in the rat with a satisfactory survival rate (69%). Functional consequences of the procedure on anima ls with uninjured spinal cord were monitored over a period of six mont hs, at which time histologic examination was performed. There was a go od correlation between operative trauma, consisting of mechanical inju ry to the cord assessed from the surgical notes, and the duration of p ostoperative spinal shock. Animals for which the cord appeared laminat ed or deformed at the time of sacrifice tended to show incomplete func tional recovery. Cord cavitation developed in most surviving animals ( 78%) but did not have a measurable adverse effect on functional outcom e. In the present study, the cord was not intentionally injured; howev er, availability of this procedure may facilitate the future developme nt of methods to implement recovery of function following spinal cord injury.