How Much Lumbar Lordosis does a Patient Need to Reach their Age-Adjusted Alignment Target? A Formulated Approach...

Area of Science:

• Spine surgery
• Orthopedic surgery
• Biomechanical analysis

Background:

• Adult spinal deformity correction aims to restore sagittal alignment.
• Achieving age-adjusted targets for spinal alignment is crucial for long-term outcomes.
• Current methods for determining optimal lumbar lordosis can be imprecise.

Purpose of the Study:

• To identify the optimal lumbar lordosis (LL) required for adult spinal deformity correction.
• To establish a predictive formula for achieving age-adjusted spinal alignment targets.
• To improve pre-operative surgical planning for spinal deformity.

Main Methods:

• Retrospective cohort study of 1048 adult spinal deformity patients.
• Multilinear regression analysis to correlate regional curvatures (LL, TK) with global alignment (TPA) based on pelvic incidence (PI).
• Development and internal validation of a predictive formula for LL.

Main Results:

• 347 patients achieved age-adjusted TPA within 5°.
• Significant improvement in sagittal parameters post-surgery (P < .001).
• A predictive formula (LL = PI - 0.3TK - 0.5Age + 10) demonstrated high accuracy (R² = .85) with low error (ME = -0.4°, AE = 5.0°).

Conclusions:

• A simple, validated formula can guide the determination of necessary LL for achieving age-adjusted spinal alignment.
• Pre-operative implementation of this formula may reduce suboptimal post-operative alignment.
• This guideline aids surgeons in optimizing surgical planning for spinal deformity correction.