A Preliminary Algorithm Using Spine Measurement Software to Predict Sagittal Alignment Following Pedicle Subtraction...

Area of Science:

• Orthopedic surgery
• Spine deformity correction
• Radiographic analysis

Background:

• Pedicle subtraction osteotomy (PSO) is a complex spinal deformity correction procedure.
• Accurate simulation of postoperative sagittal alignment is crucial for surgical planning and outcomes.
• Existing spine measurement software may have limitations in simulating post-PSO alignment.

Purpose of the Study:

• To evaluate the accuracy of spine measurement software in simulating sagittal alignment after lumbar PSO.
• To compare software-simulated measurements with actual postoperative measurements.
• To develop and validate an algorithm for improving simulation accuracy.

Main Methods:

• Retrospective case series of adult spinal deformity patients undergoing lumbar PSO.
• Preoperative and postoperative lateral standing radiographs were analyzed.
• Sagittal measurements were simulated using dedicated software and compared to actual outcomes.
• A regression equation was developed to adjust for manual film rotation and improve SVA simulation.

Main Results:

• Software accurately simulated lumbar lordosis (LL), pelvic incidence-lumbar lordosis mismatch (PI-LL), and T1 pelvic angle (TPA).
• Simulations were inaccurate for pelvic tilt (PT), sacral slope (SS), thoracolumbar alignment (TL), thoracic kyphosis (TK), T9SPi, T1SPi, and SVA.
• The developed regression algorithm improved accuracy and reduced variability for PT, SS, T9SPi, T1SPi, and SVA.

Conclusions:

• Spine measurement software can reliably simulate LL, PI-LL, and TPA after PSO.
• Simulation of PT, SS, TL, TK, T9SPi, T1SPi, and SVA requires refinement.
• A preliminary algorithm shows promise in enhancing the accuracy of certain sagittal parameters, warranting further prospective validation.