EFFECT OF OPERATIVE POSITION ON SAGITTAL ALIGNMENT OF THE LUMBAR SPINE

A variety of techniques and frames are used for positioning patients d uring posterior lumbar spinal instrumentation and fusion. Little infor mation is available on the relationship of lumbar lordosis and the var ious positioning options, so it was felt that further investigation wa s warranted. Ten volunteers with no history of back pain were position ed and radiographed in the standing position followed by four lateral radiographs with the patient positioned on chest rolls, Andrew's frame , the Hasting's frame, and a four-poster spinal frame. Total lumbar lo rdosis from L1 to S1 as well as intervertebral body angles at each of the lumbar interspaces using standardized techniques were computed, No significant difference was found in lumbar lordosis between the stand ing and chest roll position. However, there was approximately a 50% re duction in lumbar lordosis when using the Hasting's, Andrew's, and fou r-poster frame as compared to the standing and chest roll configuratio n. The clinical implications are discussed.