Temporal Shape Changes of Pedicle Screw-rod Constructs After Lumbar Interbody Fusion

• Published in: Spine (Philadelphia, Pa. 1976) Pa. 1976), 2024-11, Vol.49 (21), p.1504-1511
• Main Authors: Ikezawa, Munenari, Tanioka, Satoru, Nishikawa, Hirofumi, Aydin, Orhun Utku, Hilbert, Adam, Miyazaki, Takahiro, Fujimoto, Masashi, Ishida, Fujimaro, Kamei, Yusuke, Suzuki, Hidenori, Mizuno, Masaki, Frey, Dietmar
• Format: Article
• Language: English
• Subjects: Adult; Aged; Female; Humans; Imaging, Three-Dimensional - methods; Lumbar Vertebrae - diagnostic imaging; Lumbar Vertebrae - surgery; Male; Middle Aged; Pedicle Screws; Retrospective Studies; Spinal Fusion - instrumentation; Spinal Fusion - methods; Time Factors; Tomography, X-Ray Computed; Treatment Outcome
• ISSN: 0362-2436; 1528-1159; 1528-1159
• DOI: 10.1097/BRS.0000000000005051

Retrospective multicenter study. To examine the shape change of screw-rod constructs over time after short-segment lumbar interbody fusion and to clarify its relationship to clinical characteristics. No study has focused on the shape change of screw-rod constructs after short-segment fusion and its clinical implications. One hundred eight patients who had single-level lumbar interbody fusion with pedicle screws and cages were enrolled. Three-dimensional (3D) images of screw-rod constructs were generated from baseline CT on the day after surgery and follow-up CT and were superposed on the right and left side, respectively, using the iterative closest point algorithm. The shape change was quantitatively assessed by computing the median distance between the 3D images, which was defined as the shape change value. Among the 5 time-course categories of follow-up CT (≤1, 2-3, 4-6, 7-12, and ≥13 months), the shape change values were compared. The relationships between the shape change values and clinical characteristics, such as age, CT-derived vertebral bone mineral density, screw and rod materials, and postoperative interbody fusion status, cage subsidence, and screw loosening, were evaluated. A total of 237 follow-up CTs were included (≤1 [34 scans], 2-3 [33 scans], 4-6 [80 scans], 7-12 [48 scans], and ≥13 months [42 scans]) because many patients underwent multiple follow-up CTs. There were significant differences in shape change values among the time-course categories ( P