Does Bone Mineral Density Testing Predict Early Fixation Failure Following Reconstruction for Adult Scoliosis?: A Matched Cohort Analysis

Purpose: To compare preop BMD test scores between two matched cohorts with and without fixation failure in order to determine whether low scores are predictive of early fixation failure.

Methods: 243 patients with spinal reconstruction for adult scoliosis and preop BMD testing using DEXA were evaluated. Patients with fixation failure within one year postop were identified. Fixation failure was defined by eight radiographic criteria. This failure cohort was matched with a second cohort of patients without fixation failure (success cohort) by age, race, gender, curve magnitude, fusion levels, type of procedure, and fusion to pelvis. Preop BMD testing scores were then evaluated to determine if there was a significant difference between the two groups.

Results: 36 patients were identified in the failure cohort. The success cohort of 36 patients was matched to the failure cohort (failure v. success) by age (64+1 v. 63+3y), gender (32 v. 32 females), race (32 v. 33 Caucasian/Asian), total fusion levels (16.6 v. 15.8), preop curve magnitude (61.0 v. 61.1°), and fusion to the pelvis (17 vs. 17 cases). Mean fem neck BMD score was 0.740 in the failure cohort and 0.767 in the success cohort. Mean fem neck T-score was -1.66 in the failure cohort and -1.40 in the "success" cohort. Mean total hip BMD score was 0.848 in the failure cohort and 0.847 in the success cohort. Mean total hip T-score was -1.06 in the failure cohort and -1.10 in the success cohort. No values reached statistical significance.

Conclusions: There was no significant difference in femoral neck and total hip BMD testing between two matched cohorts with and without fixation failure. This study suggests that the utility of preop BMD testing in predicting fixation failure in patients with adult scoliosis undergoing spinal reconstruction may be limited.