MDCT-Based Finite Element Analysis for the Prediction of Functional Spine Unit Strength-An In Vitro Study

(1) Objective: This study aimed to analyze the effect of ligaments on the strength of functional spine unit (FSU) assessed by finite element (FE) analysis of anatomical models developed from multi-detector computed tomography (MDCT) data. (2) Methods: MDCT scans for cadaveric specimens were acquired from 16 donors (7 males, mean age of 84.29 & PLUSMN; 6.06 years and 9 females, mean age of 81.00 +/- 11.52 years). Two sets of FSU models (three vertebrae + two disks), one with and another without (w/o) ligaments, were generated. The vertebrae were segmented semi-automatically, intervertebral disks (IVD) were generated manually, and ligaments were modeled based on the anatomical location. FE-predicted failure loads of FSU models (with and w/o ligaments) were compared with the experimental failure loads obtained from the uniaxial biomechanical test of specimens. (3) Results: The mean and standard deviation of the experimental failure load of FSU specimens was 3513 +/- 1029 N, whereas of FE-based failure loads were 2942 +/- 943 N and 2537 +/- 929 N for FSU models with ligaments and without ligament attachments, respectively. A good correlation (rho = 0.79, and rho = 0.75) was observed between the experimental and FE-based failure loads for the FSU model with and with ligaments, respectively. (4) Conclusions: The FE-based FSU model can be used to determine bone strength, and the ligaments seem to have an effect on the model accuracy for the failure load calculation; further studies are needed to understand the contribution of ligaments.

Automated summary

The study aimed to analyze the effect of ligaments on the strength of the functional spine unit (FSU) using finite element analysis. Results showed that ligaments have an impact on the accuracy of the model for failure load calculation, and further studies are needed to fully understand their contribution.