Breakage and deformation characteristics of hypodermic devices under static and dynamic loading

Objective-To characterize the strength and limitations of hypodermic needles to reduce the risk of leaving broken needles in the flesh of animals. Sample Population-Skin of porcine cadavers. Procedure-Stainless steel needles of various gauges combined wit aluminum and plastic hubs were subjected to standard test-stand conditions to compare strength under various loading regimens. A device that simulated animal motion was constructed to test breakage characteristics during animal movement. Results-Needles and needle/hub assemblies were resilient to needle breakage, except when bent needles were straightened and a load reapplied. Needle gauge and length drastically affected strength. For 16- and 20-gauge needles, a 1.0-in needle was 1.6 times stronger than a 1.5-in needles resulted in a 40% increase in hub failures for plastic, compared to aluminum hub needles. Conclusions and Clinical Relevance-Findings of this study are important considerations for meat packers to address in their Hazard Analysis and Critical Control Points plans.