RESUMEN
Objective To study the application value of direct digital X‐ray radiography system in the degenerative lumbar insta‐bility .Methods 100 patients with degenerative lumbar instability disease were collected in our hospital ,in which there were L4 ,L5 (80 cases) and L5 ,S1 (20 cases) with degenerative lumbar instability disease .Carestream DRX‐Evolution system was used ,which included conventional horizontal lumbar function photography (control group) and physiological load of lumbar function photography (observation group) .Changes of the displacement or the angle of the lumbar segment on two groups were measured ,and the statisti‐cal software was used to carry on the comparative analysis .Results In 100 patients ,the position and the physiological load position were showed on the sagittal position which were as following :For the lumbar segment of L4 and L5 ,flexion [position (4 .50 ± 0 .25) mm , load position (4 .78 ± 0 .30) mm] ,extension [position (4 .87 ± 0 .22) mm ,load position (5 .18 ± 0 .30) mm] ,and for the lumbar segment of L5 and S1 ,flexion [position (4 .64 ± 0 .24) mm ,load position (4 .91 ± 0 .24) mm] ,extension [position (4 .95 ± 0 .30) mm , load position (5 .30 ± 0 .29) mm];For the intervertebral angle degree of L4 and L5 ,flexion (position 10 .64° ± 0 .29° ,load position 12 .12°± 0 .57°) ,extension (position 11 .57°± 0 .24° ,load position 12 .61°± 0 .28°);For the intervertebral angle degree of L5 and S1 , flexion (position 11 .63° ± 0 .26° ,load position 12 .72° ± 0 .27°) ,extension (position 13 .55° ± 0 .30° ,load position 14 .58° ± 0 .33°) , respectively .The difference between two groups was statistically significant (P< 0 .05) .Conclusion Compared with traditional method ,DR lumbar physiological weight‐bearing functional can more accurately understand the lumbar instability degree ,grading and lumbar positive rate ,which provides the basis for clinical diagnosis and treatment plan .