Comparison of modified Thiel formalin-free embalming with traditional Thiel and formalin techniques in a rabbit model for soft cadaver preservation

Cadavers are essential tools for teaching gross anatomy to medical and health science students. Traditional formalin-embalmed cadavers preserve anatomical structures but exhibit rigidity and limited joint mobility, making dissection difficult. While the Thiel embalming method preserves lifelike properties, the presence of formalin/formaldehyde raises occupational health concerns. This study evaluates a modified formalin-free Thiel solution (FF) compared to the original Thiel solution (TS) and conventional formalin solution (CF). Nine rabbits were allocated to three groups and preserved for one month. Unlike CF and TS-preserved specimens, FF-preserved cadavers did not produce an irritating odor. FF and TS specimens retained flexibility, allowing easy dissection, while CF cadavers were more rigid. FF- and TS-preserved tissues exhibited natural skin and organ appearance, contrasting with the distorted appearance of CF-preserved samples. FF and TS groups showed significantly higher joint mobility, skin elasticity, and muscle springiness than CF, while their hardness was lower. Moisture content in FF- and TS-preserved muscles was also significantly higher than those preserved in CF. The findings demonstrate that FF-preserved cadavers are comparable to TS-preserved cadavers in tissue preservation, highlighting FF as a promising formalin-free alternative. This solution offers safe and effective preservation for traditional dissection and is suitable for surgical skills training and medical research, providing real tissue quality without the health risks associated with formalin.