Study design:

Retrospective Cohort Study.

Objectives:

To investigate and compare the prevalence of low bone mineral density (BMD) and abnormal laboratory bone metabolism parameters in patients undergoing elective primary discectomy, decompression, and fusion and to outline possible differences in these parameters between patients undergoing revision for skeletal vs non-skeletal complications.

Methods:

We retrospectively evaluated BMD measurements by dual-energy x-ray absorptiometry (DXA) in 389 consecutive patients scheduled for elective lumbar spine surgery. Next to demographic characteristics, laboratory bone metabolism parameters were assessed. Group comparisons were performed between primary discectomy, decompression, and fusion. In patients scheduled for revision surgery after fusion, potential differences in the skeletal status between those with skeletal vs non-skeletal complications were analyzed.

Results:

Osteoporosis by T-score was detected in 6.7%, 11.0% and 14.7% of the patients undergoing discectomy, decompression and fusion, respectively. While vitamin D deficiency (67.6%) and hyperparathyroidism (16.4%) were frequently detected, no differences in laboratory bone metabolism markers could be found between the groups. Female sex (P<.001), higher age (P=.01) and lower BMI (P<.001) were associated with lower BMD. In the cohort of patients undergoing revision surgery due to complications after fusion, those with skeletal complications did not differ in BMD or bone metabolism from those with non-skeletal complications.

Conclusions:

Osteoporosis represents a relevant comorbidity in patients scheduled for elective spine surgery, which is why DXA should be routinely performed in these patients. However, DXA may provide limited information in identifying patients at increased risk for skeletal complications after fusion.