PASSIVE REDUCTION OF SPONDYLOLISTHESIS ON THE OPERATING-ROOM TABLE - A PROSPECTIVE-STUDY

Translational motion of low-grade spondylolisthesis is traditionally a ssessed with lateral flexion and extension radiographs. Maximum motion in an unanesthetized patient may be limited by patient cooperation, p ain, or muscle spasm. Twenty-four patients with degenerative or isthmi c spondylolisthesis were assessed with preoperative lateral flexion an d extension radiographs. A lateral radiograph was obtained on the oper ating room table after administering an anesthetic, exposing the spine , and performing a laminectomy. The percentage slip decreased from 24 to 15 to 6% on flexion, extension, and intraoperative lateral radiogra phs, respectively (p < 0.001). The amount of reduction did not correla te with disc height, slip angle, slip level, or type of spondylolisthe sis. Many low-grade spondylolisthesis deformities reduce almost comple tely on the operating table. Translational motion of spondylolisthesis is greater than preoperative flexion and extension radiographs indica te.