Abstract
Background: Bone health has emerged as a critical modifiable risk factor for complications following adult spinal deformity correction. Among these complications, mechanical issues and proximal junctional kyphosis/failure remain particularly challenging, affecting up to 61% and 44% of patients, respectively. We hypothesized that osteoporotic patients undergoing deformity correction experience higher rates of instrumentation failure and proximal junctional kyphosis/failure.
Purpose: To evaluate and compare the complication profiles of osteoporotic and non-osteoporotic patients undergoing long thoracolumbar fusion for adult spinal deformity.
Study Design: Retrospective comparative study
Patient Sample: adult spinal deformity patients who underwent long thoracolumbar spinal fusion (>7 levels) at two large academic medical centers between 2010 and 2019.
Outcome Measures: The primary outcome was all-cause revision surgery. Secondary outcomes included pseudarthrosis with or without implant failure, proximal junctional kyphosis/failure rates, infection rates, and time to complication occurrence.
Methods: This retrospective, multicenter study analyzed deformity patients undergoing long-segment instrumentation (≥7 levels) with a minimum two-year follow-up. Exclusion criteria included spinal deformity secondary to tumor, infection, trauma, or neuromuscular disorders. Preoperative osteoporosis status was determined using dual-energy X-ray absorptiometry (DXA) T-scores at the hip and femoral neck. The complication profiles of osteoporotic and non-osteoporotic deformity patients were compared using Chi-squared or Fisher’s exact tests for categorical variables and two-tailed t-tests for continuous variables.
Results: Among 399 adult spinal deformity patients, 131 (32.8%) were osteoporotic. Osteoporotic patients were significantly older than their non-osteoporotic counterparts [66.43 (SD: 8.9) vs. 63.51 (SD: 8.9), P = 0.0018]. The overall complication rate was significantly higher in osteoporotic patients compared to non-osteoporotic patients [40.5% (n = 53) vs. 28.0% (n = 75), P = 0.0122]. Incidences of PJK [35.1% (n = 46) vs. 21.6% (n = 58), P = 0.0040] and PJF [19.8% (n = 26) vs. 6.7% (n = 18), P = 0.0001] were also higher in the osteoporotic group, while rates of construct failure/pseudarthrosis [11.5% vs. 15.7%, P = 0.2578] and infection [4.6% vs. 3.7%, P = 0.6849] showed no significant differences. Time to pseudarthrosis (8.1 vs. 8.3 months, P = 0.4582), infection (4.7 vs. 1.5 months, P = 0.0773), PJF (9.3 vs. 10.1 months, P = 0.7300), and overall time to first complication (8.4 vs. 7.6 months, P = 0.5119) were similar between the groups.
Conclusions: Osteoporotic patients have increased risk of proximal junctional kyphosis and failure compared to non-osteoporotic patients, highlighting the need for preoperative osteoporosis surveillance, optimization, and postoperative monitoring to mitigate complications.