How Does the Lordosis Apex, Lordosis Arcs, and Inflection Point According to Roussouly Predict Outcomes After Adult...

Area of Science:

• Spine surgery
• Orthopedic surgery
• Deformity correction

Background:

• The impact of lordosis apex, arcs, and inflection point on postoperative outcomes in adult spinal deformity (ASD) surgery is not well understood.
• Restoring spinal alignment and sagittal balance is crucial for successful ASD surgery.

Purpose of the Study:

• To report preoperative and postoperative lordosis apex, number of vertebrae in lordosis arcs, and inflection point in ASD surgery patients.
• To determine the impact of these parameters on postoperative outcomes, including complications and patient-reported measures.

Main Methods:

• Retrospective cohort study of 202 adult spinal deformity patients with ≥5-level fusion and ≥2-year follow-up.
• Analysis of pre/postoperative lordosis apex, vertebrae in upper/lower arcs, and inflection point.
• Multivariable regression controlling for age, BMI, and comorbidities to assess outcomes like mechanical complications, reoperations, and alignment.

Main Results:

• Postoperatively, 61.9% of patients experienced a cranial lordotic apex shift, associated with decreased L4-S1 lordosis and increased 2-year back pain.
• An increase in upper lordotic arc vertebrae correlated with higher back pain.
• Preoperative inflection points outside T12/L1 were linked to more spinopelvic complications (38.8% vs. 22.1%).

Conclusions:

• Post-ASD surgery, cranial lordotic apex shifts are common, with difficulty in restoring caudal lordosis.
• Cranial apex shift and preoperative inflection points outside T12/L1 are associated with poorer outcomes and increased complications.
• Incorporating Roussouly principles may aid surgeons in improving outcomes and mitigating complications in ASD surgery.