Restoration of the spinal canal by the internal fixator and remodeling.

It has been observed that after reduction of an unstable vertebral fracture, treated either conservatively or operatively, the encroachment of the spinal canal remaining after reduction can decrease considerably with time. A series of 31 cases, each with a set of CT scans taken preoperatively, immediately after surgery and after implant removal respectively, was assessed using computer-aided planimetry. The mean initial narrowing of the spinal canal was 44.6%. Through surgery this was decreased by 20.4%, leaving a remaining deficit of 24.2%. After implant removal, 15 months after trauma and surgery, the area of the spinal canal increased a further 17.4%, leaving a remaining deficit of only 6.8%. Comparing the values of the spinal canal for T12-L5 directly after surgery and after implant removal, an almost identical degree of restoration for each level can be seen. This additional and gradual restoration of the spinal canal is termed remodeling. This study demonstrates that a residual postoperative narrowing of the spinal canal of up to 25% can be ignored, provided there is no initial neurologic damage.