Can abdominal aortic calcification detected on lateral lumbar radiography predict instrument-related complications in patients undergoing posterior lumbar fusion?

Objective: Abdominal aortic calcification (AAC) is well known as a useful and simple clinical indicator of the risk of fracture and cardiovascular disease. However, no studies have directly compared the postoperative implications of AAC in spinal surgery. The purpose of this study was thus to examine whether extended AAC (scores ≥5) negatively affected clinical outcomes after posterior lumbar fusion with instrumentation for degenerative lumbar stenosis or degenerative spondylolisthesis.Methods: The subjects comprised 101 consecutive patients with spinal stenosis or degenerative spondylolisthesis who underwent posterior lumbar fusion and instrumentation between January 2016 and January 2019 and were followed for over 2 years. Propensity score matching was employed to assemble patient groups with similar baseline characteristics. Postoperative complications and radiologic outcomes were compared between the groups (33 patients in each) divided by extended AAC score.Results: The incidence rates of junctional failure (6.1% vs. 30.3%, P=0.008) and screw-related complications (12.1% vs. 36.4%, P=0.019) were higher in the extended AAC group than in the mild AAC group. However, the rates of adjacent segment disease (24.2% vs. 36.4%, P=0.283) and revision (6.1% vs. 9.1%, P=0.642) were not significantly different between the 2 groups. In terms of postoperative medical complications, cardiovascular and cerebrovascular diseases were significantly more common in the extended AAC group than in the mild AAC group (0% vs. 15.2%, P=0.020).Conclusion: Extended AAC indicates increased risk for postoperative junctional failure and screw-related complications, regardless of age, osteoporosis, and comorbidities.