Methods: Preoperatively, all 115 patients underwent BMD assessments using both CT-derived HUs and dual-energy X-ray absorptiometry and were administered multiple questionnaires, including the Pain Catastrophizing Scale (PCS), Beck Anxiety Inventory (BAI), and Beck Depression Index (BDI). Both pain intensity and pain-related disability were assessed before and after lumbar fusion surgery. Results: Postoperatively, 14 patients (14/115, 12.2%) experienced FBSS. Multivariate logistic regression was used to examine all preoperative covariates with significant differences between the patients with and without FBSS. The numeric rating pain scale score at rest, BAI score, PCS score, and HU value were found to be independently associated with FBSS (p<0.05). Conclusions This study revealed that preoperative BMD, as quantified by CT-derived HU values, may be associated with FBSS. Preoperative assessments of CT-derived HU values might provide additional details for identifying patients susceptible to FBSS, which could help prevent this complication.