Radiolucent Zones Surrounding Transpedicular Screws After Lumbar Spinal Instrumented Fusion / 대한척추외과학회지

ABSTRACT

STUDY DESIGNS A retrospective study for radiographic and clinical assessment. OBJECTIVES: To clarify the clinical significance of the radiolucent zones surrounding transpedicular screws that occasionally appears following lumbar spinal instrumented fusion. SUMMARY OF LITERATURE REVIEW that the formation of radiolucent zones surrounding pedicular screws are significantly frequent after transpedicular fixation. MATERIALS AND METHOD: 88 cases, age 50 or older, which underwent lumbar spinal fusion with transpedicular screws, between January 1999 and December 2002, were included in this investigation. The postoperative radiographs of all patients were analyzed for radiolucent zones around the transpedicular screws. These radiolucent zones were evaluated in relation the number of fusion levels, the existence of osteoporosis, and the fusion status and satisfaction rates. RESULTS: Radiolucent zones were observed in 30 cases (34%, 30/88), 13 (43%, 13/30) of which disappeared during the follow-up period. The average number of fixation levels in the cases with and without radiolucent zones were 2.33 (range 1-4, SD 0.94) and 1.74 (range 1-4, SD 0.82), respectively. Osteoporosis was found to accompany 43.3 and 20.7% of the cases with and without radiolucent zones, with the latter cases showing a statistically significant higher fusion rate and greater patient satisfaction. CONCLUSION: Radiolucent zones, a frequent finding following pedicle screw fixation, resulted in less favorable outcomes. Surgeons should be alert to radiolucent zones and their transformation during follow-up. Methods for improving the stability of the interface between the pedicle screw and vertebral bone will require further research.