Mechanical Analysis of Needles Used in Ultrasound-Guided Musculoskeletal Interventions.

We performed a mechanical analysis of the commonly used needles for ultrasound-guided interventions in the musculoskeletal system. Specifically, focusing on the ability to absorb potential physical loads and the degree of deformation during the procedure, the needle gauge best suited for those procedures is evaluated. A customized tensile-compression device was used for an experimental buckling strength test on three commonly used needle types with specific gauge sizes. The loss of structural integrity, loss of needle stability, and buckling load were modeled also theoretically using finite element analysis software. Theoretical software needle buckling analysis detected the load for the first buckling mode of the needle, when the highest value was reached for the G20 needle with the load 18.8 N. The load for G21 needle was 9.7 N and for G23 8 N. Experimental data with customized tensile-compression device aligned theoretical data when the highest value was reached for the G20 needle with the load 19.7±1.9 N. The load for G21 needle was 10.6+/-2.7 N and for G23 7.9+/-0.7 N. Theoretical and practical experiments have shown that the standard G20 needle model exhibits the highest mechanical tolerance for potential interventions in the musculoskeletal system. Key words Interventional ultrasound " Needle " Buckling strength.