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Updated: May 27, 2026
Evaluation of Patients' Posture and Gait Profile After Lumbar Fusion Surgery by Video Rasterstereography and Treadmill Gait Analysis
Published on: March 23, 2019
Instrumented vs Non-Instrumented Fusion for Elderly Patients with Lumbar Spondylotic Conditions: A Causal Inference
Brendan M Striano1, Kaitlyn E Holly, Tino Mukorombindo
1Department of Orthopaedic Surgery, Mass General Brigham, Harvard Medical School, 75 Francis Street, Boston, MA 02115.
Study Design:
Retrospective study using causal inference techniques.
Objective:
To apply causal inference techniques and a single-surgeon study design to more effectively address confounding by indication inherent to prior research on instrumented vs non-instrumented fusion in elderly patients. We hypothesized that non-instrumented fusion would be associated with lower rates of reoperation at two years.
Summary Of Background Data:
There has been renewed interest in non-instrumented approaches in the context of payment reform and increased sensitivity to the impact of high intensity surgery on elderly patients and those with frailty. Previously published randomized trials on instrumented vs non-instrumented procedures are not informative for elderly individuals and those with frailty.
Methods:
We identified individuals 65 and older who received instrumented, or non-instrumented, decompression and fusion for degenerative lumbar indications in a single surgeon practice. The primary outcome was reoperation within two years of surgery. The primary predictor was instrumented versus non-instrumented fusion. To account for confounding by indication in the decision to use instrumentation, we used propensity-score weighting that accounted for age, biologic sex, body mass index, co-morbidities, the number of levels decompressed and the number of levels fused.
Results:
This study included 248 patients; 181 who underwent instrumented fusion and 67 who received non-instrumented fusion. Following propensity-score weighting, non-instrumented fusion was significantly associated with increased odds of reoperation (OR 1.83; 95% CI 1.05, 3.25; P=0.04). When limiting consideration to reoperations performed for mechanical failure, adjacent segment degeneration or symptom recurrence/incomplete resolution there was no significant difference in reoperation (OR 0.86; 95% CI 0.39, 1.84; P=0.69).
Conclusions:
When accounting for selection and indication bias, instrumented fusion results in a significantly lower rate of reoperation even in those with more advanced age and frailty. We believe that the use of instrumentation represents the preferred approach when fusion is indicated except in rare situations.
Level Of Evidence:
III.
