European Spine Journal - 2026-03-19 - Journal Article
Factors associated with favorable outcomes of floating fusion or lumbosacral spinal fusion in adult spinal deformity surgery: an analysis of the incidence of mechanical complications from a multicenter study.
Kagami Y, Nakashima H, Segi N, Ito S, Ouchida J, Yamauchi I, Ode Y, Nagatani Y, Okada Y, Takeichi Y, Shinjo R, Ohara T, Tsuji T, Kanemura T, Imagama S
Topics
Key Takeaway
In floating fusion for ASD, mechanical complications were associated with significantly less lumbar lordosis correction (2.1° vs 9.3°, p=0.04) and less PI-LL correction (-2.1° vs -10.6°, p=0.02) compared to complication-free cases.
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Summary
This multicenter retrospective study compared floating fusion (FF) versus lumbosacral fusion (LSF) in ASD patients, identifying predictors of surgical approach selection and mechanical complication (MC) risk within each group. Fewer fusion levels (OR 0.50), greater thoracic kyphosis (OR 1.03), and preserved lower lumbar lordosis (OR 1.07) independently predicted FF selection. Within FF, inadequate LL and PI-LL correction drove MCs; within LSF, higher preoperative SVA (103.1 vs 82.5 mm, p=0.049) was the primary MC predictor.
Key Limitation
The total sample size is unreported in the abstract, making it impossible to determine whether the MC subgroup comparisons are adequately powered, particularly for the LSF SVA finding that reached only marginal significance (p=0.049).
Original Abstract
PURPOSE
Lumbosacral fusion (LSF) is the standard approach in adult spinal deformity (ASD) surgery but is frequently associated with proximal junctional kyphosis. Floating fusion (FF) has been proposed as an alternative approach. This study examined factors influencing the selection of FF and identified postoperative adverse factors associated with each surgical approach.
METHODS
This multicenter study retrospectively reviewed the records of patients who underwent surgery for ASD. They were divided into FF and LSF groups and compared by baseline patient characteristics and radiological parameters. Each group was further divided and compared according to mechanical complications (MC).
RESULTS
The number of fusion levels (odds ratio [OR] = 0.50, 95% confidence interval [CI]: 0.41-0.61, P < 0.01), thoracic kyphosis (OR = 1.03, 95% CI: 1.00-1.06, P = 0.045), and lower lumbar lordosis (LL) (OR = 1.07, 95% CI: 1.03-1.10, P < 0.01) were independently associated with FF. In FF, the correction amounts for LL and PI - LL were lower in the MC subgroup (LL: no MC, 9.3 ± 12.5; MC, 2.1 ± 16.1, P = 0.04 and
PI - LL
no MC, - 10.6 ± 12.3; MC, - 2.1 ± 14.1, P = 0.02). In LSF, the preoperative SVA was higher in the MC subgroup (no MC, 82.5 ± 55.4; MC, 103.1 ± 46.7; P = 0.049).
CONCLUSION
FF outcomes were more favorable in patients undergoing short-segment fusion who retained TK or lower lumbar lordosis. Various procedural demands influenced postoperative MC: FF requires LL proportional to the PI, whereas LSF focuses on global alignment correction.