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

Abstract

Abstract 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 with 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 needle. Adding animal movement for 20-gauge, 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.(Am J Vet Res 1999;60:292–298)