# Comparative Evaluation of Compression Testing Methods for Murine Lumbar Vertebral Bodies: Identifying Most Reliable and Reproducible Techniques for Assessing Compressive Strength

## TL;DR

This study compares four methods for testing the compressive strength of mouse vertebrae and finds that one method provides the most reliable and consistent results.

## Contribution

The paper identifies the most reproducible compression testing method for murine lumbar vertebral bodies.

## Key findings

- Method 1 showed the highest load-to-failure and yield-to-failure with the least variation.
- Method 3 had higher stiffness and Young’s modulus but inconsistent results.
- Method 2 is recommended if spinal processes must be excluded due to acceptable data quality.

## Abstract

This study evaluates four compression testing methods to determine the most reliable and reproducible technique for assessing the compression strength of murine lumbar vertebral bodies. Twenty female C57BL/6 mice (12 weeks old) were randomized into four groups: Group 1, compression of the complete lumbar vertebral body (LVB) with dorsal spinal processes; Group 2, compression at the vertebral body surface; Group 3, compression at the vertebral body surface after vertebral arch resection; Group 4, resection of the vertebral arch with straightening of the intervertebral joint surface. A mono-axial static testing machine applied compression, measuring load to failure, stiffness, yield load, and elasticity modulus. Method 1 resulted in significantly higher load-to-failure and yield-to-failure (25.9 N compared to 18.2 N, and twice 12 N for Methods 2–4), with the least variation in relative values. Method 3 had increased stiffness and a significantly higher Young’s modulus (232 N/mm, in contrast to 101, 130, and 145 N/mm for Methods 1, 2, and 4, respectively) but yielded inconsistent results. Method 4 showed the greatest variability across specimens. Method 2 yields suitable data quality as well, albeit with a slightly higher variation, and is the recommended procedure if the spinal processes have to be excluded from the measurement. Based on these findings, Method 1 produced the most consistent and reproducible data and is recommended for future studies evaluating vertebral biomechanics in mice.