Visiting Scholar, Spine Surgeon Virginia Mason Medical Center
Disclosure(s):
Takeshi Fujii, MD: No financial relationships to disclose
Introduction: This study evaluates the effect of anterior lumbar interbody fusion (ALIF) on coronal spinal balance, both alone and combined with posterior spinal fusion (PSF).
Methods: A retrospective review was conducted on 48 patients with adult spinal deformity (ASD) and a main curve Cobb angle ≥20°, all of whom underwent ≥6 levels of thoracolumbar fusion with ALIF. Radiographic parameters, including L4 tilt, L5 tilt, and fractional curve (FC), were measured in the supine position. Preoperative and intraoperative radiographs assessed ALIF alone, while preoperative and postoperative radiographs evaluated ALIF with PSF. ALIF correction was calculated as the ratio of the mean absolute difference between preoperative and intraoperative values to the mean absolute change between preoperative and postoperative values.
Results: In 22 L5-S1 cases, significant differences were found between preoperative and intraoperative measurements for L4 tilt (Δ = 2.26° ± 2.74, P = 0.004) and FC (Δ = 3.84° ± 2.78, P < 0.001), but not for L5 tilt (Δ = 1.65° ± 1.40, P = 0.14). Preoperative to postoperative changes were significant for L4 tilt (Δ = 4.53° ± 3.42, P < 0.001), L5 tilt (Δ = 2.55° ± 2.36, P < 0.001), and FC (Δ = 8.83° ± 5.82, P < 0.001). The ALIF correction proportions were 48.40% for L4 tilt, 64.19% for L5 tilt, and 43.51% for FC. In 26 L4-S1 cases, significant differences were found between preoperative and intraoperative for L4 tilt (Δ = 5.43° ± 3.53, P < 0.001), L5 tilt (Δ = 4.17° ± 3.19, P = 0.005), and FC (Δ = 7.26° ± 6.76, P < 0.001). Preoperative to postoperative changes were significant for L4 tilt (Δ = 3.64° ± 2.67, P < 0.001), L5 tilt (Δ = 3.67° ± 3.11, P < 0.001), and FC (Δ = 4.44° ± 3.64, P < 0.001). The ALIF correction proportions were 58.46% for L4 tilt, 68.93% for L5 tilt, and 57.57% for FC.
Conclusion : As fusion levels increase from L5-S1 to L4-S1, ALIF plays a greater role in coronal correction, with PSF contributing less.
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