Se-Jun Park, Jin-Sung Park, Dong-Ho Kang, Tae Soo Shin, Jun-Seok Oh, Joon Young Jung, Jae-Won Hur, Chong-Suh Lee
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引用次数: 0
Abstract
Study design: Retrospective cohort study.
Objective: To determine whether a residual positive T4-L1PA mismatch predicts mechanical failure after lower thoracic fusion, and to identify factors associated with failure to achieve the target.
Summary of background data: The T4-L1-Hip axis defines sagittal alignment using two vertebral pelvic angles that are fixed or directly modifiable in surgery. When fusion stops in the lower thoracic region, T4 remains above the construct and outside the surgeon's control.
Methods: Patients who underwent fusion from T9-L1 to the pelvis between 2015 and 2024 with two-year follow-up were reviewed. Sixteen with a mismatch below -4° were excluded, leaving 357 patients. A mismatch within ±4° was defined as matched and one above +4° as a residual positive mismatch. Proximal junctional kyphosis (PJK), rod fracture, and revision surgery were assessed by Firth penalized logistic regression with covariates specified a priori.
Results: A residual positive mismatch was present in 140 patients (39.2%). PJK occurred in 35.0%, rod fracture in 9.2%, and revision in 15.4%. A residual positive mismatch was associated with PJK (odds ratio [OR] 1.83, P=0.011) and revision (OR 2.40, P=0.004) but not rod fracture (OR 1.19, P=0.639). A hyperlordotic lordosis distribution index (LDI) was its strongest determinant for a residual positive T4-L1PA mismatch (OR 5.40, P<0.001). The L1PA offset showed no association (P=0.150); 14 of 19 patients (73.7%) who met the L1PA target with a hyperlordotic LDI still had a residual mismatch. L1 tilt increased across the LDI categories whereas T4 tilt did not.
Conclusions: A residual positive T4-L1PA mismatch after lower thoracic fusion was associated with PJK and revision surgery, but not with rod fracture. A hyperlordotic distribution of lordosis, rather than the magnitude of correction, was associated with this residual mismatch.
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Recognized internationally as the leading journal in its field, Spine is an international, peer-reviewed, bi-weekly periodical that considers for publication original articles in the field of Spine. It is the leading subspecialty journal for the treatment of spinal disorders. Only original papers are considered for publication with the understanding that they are contributed solely to Spine. The Journal does not publish articles reporting material that has been reported at length elsewhere.
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