Adjacent Vertebral BMD Decline After Lateral Lumbar Interbody Fusion

Area of Science:

• Spinal surgery
• Orthopedics
• Radiology

Background:

• Lateral lumbar interbody fusion (LLIF) may protect spinal ligaments, potentially impacting bone mineral density (BMD).
• Limited evidence exists on vertebral bone density changes post-LLIF.
• Altered bone density is linked to mechanical complications like kyphosis and adjacent fractures.

Purpose of the Study:

• To investigate volumetric bone mineral density (vBMD) changes in adjacent cancellous bone and endplates after LLIF.
• To assess the impact of LLIF on vertebral bone density.
• To identify potential risk factors for mechanical complications.

Main Methods:

• Retrospective analysis of 32 patients undergoing LLIF for degenerative lumbar diseases.
• Quantitative CT (QCT) used to measure vBMD of adjacent cancellous bone and endplates (UIV+1, LIV+1, UIV+1e, LIV+1e) pre- and post-operatively.
• Statistical analysis including Shapiro-Wilk test, ANOVA, Mann-Whitney, Fisher exact, and ROC curve analysis.

Main Results:

• Postoperative vBMD was significantly lower than preoperative vBMD in all measured regions (p < 0.001 to p = 0.042).
• Significant decreases in vBMD were observed: 16.1% in UIV+1, 12.2% in LIV+1, 11.4% in UIV+1e, and 7.2% in LIV+1e.
• No significant difference in vBMD changes between upper (UIV+1) and lower (LIV+1) instrumented vertebrae, but endplate vBMD differed significantly at follow-up (p=0.035).

Conclusions:

• LLIF is associated with a reduction in vBMD of adjacent cancellous bone and endplates.
• QCT evaluation of vBMD changes can provide a novel approach to mitigate mechanical complications after vertebral fusion.
• Understanding these bone density changes is crucial for improving patient outcomes post-LLIF.