Early and Long-Term Changes in Adjacent Vertebral Body Bone Mineral Density Determined by DEXA After Posterolateral Fusion with Transpedicular Screw Fixation in Elderly Patients: A Retrospective Study.

Abstract

To quantitatively investigate adjacent vertebral bone mineral density (BMD) changes in elderly patients after lumbar posterolateral fusion with transpedicular screw fixation in short and long terms via dual-energy X-ray absorptiometry (DEXA). A retrospective study was performed to investigate adjacent vertebral body BMD changes in 82 patients who underwent posterolateral fusion with transpedicular screw fixation at the lumbar spine. Patients were divided into 5 groups based on the follow-up period: group A (3 months), group B (6 months), group C (12 months), group D (24 months), and group E (36 months) postoperatively. BMD values were measured from L1 to L4 using quantitative DEXA. Comparisons were assessed using appropriate statistical methods. Baseline characteristics were comparable across groups in 82 patients (mean age 61 years; male: female 1:1.28; BMI 24 kg/m²; BMD 0.91 g/cm²). Compared with preoperative BMD, mean BMD significantly decreased in Groups A (P < 0.001), B (P < 0.001), and C (P = 0.033), but no significant changes were observed in Groups D (P = 0.139) and E (P = 0.906). According to adjacent vertebral level, significant BMD declines were noted in 1-level to 3-level in Groups A and B, in 1-level and 2-level in Group C, only in 1-level in Group D, and in no vertebrae in Group E. BMD of vertebrae adjacent to the fused segment showed a marked decline at 3-12 months postoperatively, with recovery evident after 1 year. This pattern highlights the clinical relevance of postoperative anti-osteoporosis strategies to mitigate fracture risk in elderly patients.