To investigate the shortsegment pedicle screw in treating degenerative L4 spondylolisthesis and the relationship of the preliminarily bending degree of the titanium rod with the lumbar lordosisangle, the slipping angle and the slipping percentage and to evaluate the clinical coincidence and curative effects of the preliminarilybent rod. MethodsFrom September 2005 to March 2007, 31 female patients (age, 40-70 years; average, 58.3 years) were admitted for surgical treatment of their L4 degenerative spondylolisthesis (MeyerdingⅠ°, Ⅱ°)． Their lumbar lordosis angle （x1）, slipping angle (x2), and slipping percentage (x3) were measured in the L4,5 segment before operation. During the operation, the titanium rod bent beforehand according to the corresponding standards was inserted. The angle of the bent rod (Y) was measured, and then the multiple linear regression equation was established. The regression equation was applied to the surgical treatment of the 30 patients.Results According to the criteria in the JOA scoring system, the 31 patients had scores of 8.300± 1.080 and 26.916±1.859 before operation and after operation, respectively. There was a significant difference between before operation and after operation（P lt;0.05）. The established multiple linear regression equation was as follows:Y=0.1390-0.327logx1+0.463x2+0.288x32．The operating time was 51.290±3.408 min in the 30 patients who underwent an insertion of the preliminarilybent rod during the operation; however, the operating time was 102.360±5.004 min in the 31 patients who underwent an insertion of the bent rod that was made based on experience during the previous operations. There was a significant difference in the operating time between the two kinds of the rods （P lt;0.05）. Estimated according to 90%, 95% and 99% of the areas under the normalcurve, the clinical coincidence rates in the preliminarily bending degrees of the titanium rod in the 30 patients were 80.00％，90.00％ and 96.67％, respectively.Conclusion The titanium rod that has been bent into a certain angle before operation according to the established criteria can definitely diminish its strain during operation and efficiently shorten the operating time．Thiskind of the titanium rod has a good coincidence in clinical application and can be effectively used in clinical practice.It is worth reference during the clinical operation.

Citation： CHU Ge,BAI Jingping,XILINBaoleri,et al.. CLINICAL APPLICATION OF SHORT SEGMENT PEDICLE SCREW IN TREATING DEGE NERATIVEL4 SPONDYLOLISTHESIS. Chinese Journal of Reparative and Reconstructive Surgery, 2007, 21(12): 1295-1298. doi: Copy