Effects of different cadaver preservation methods on muscles and tendons: a morphometric, biomechanical and histological study.

No prior publication studying the biomechanical and histological properties of cadavers fixed with Logan or modified Logan solution (MLS) was found in the literature. It was aimed in this study to compare MLS fixation and other cadaver preservation procedures regarding the use in basic histological studies, anatomy education and surgical trainings. This study was placed on 35 male 17-week-old Wistar Albino rats. MLS fixated tissues were systematically compared with 10% formalin (F10), saturated salt solution (SSS), Thiel and frozen/thawed (FT) tissues. Organoleptic (color, appearance, flexibility, odor, etc.), morphometric (e.g. length, width and cross-sectional area), biomechanical (Young's modulus, stiffness, maximum load, etc.) and histological (tendon and muscle fiber integrity, nuclear prominence, blur in microscopy, etc.) analyses were conducted. Organoleptic properties of Thiel and SSS fixated muscles and tendons were better preserved than F10 and MLS. No significant difference was observed in gross morphometric properties (e.g. length, width and cross sectional area) following any of the cadaver and tissue preservation techniques. MLS and F10 was observed to increase the stiffness, Young's modulus and maximum load parameters of the tendons. Thiel and SSS fixated tendons had similar mechanical properties to fresh and FT tendons. No effect of fixation solutions on tendons is observed in the histological analysis regarding fiber integrity, nuclear prominence, blur in microscopy, shrinkage of tissues. Thiel solution was observed to distort fiber integrity, nuclear prominence and blur the microscopy of muscle tissue. Thiel and SSS fixated muscles and tendons were observed to absorb more stain with Masson's trichrome staining and appear as darker red. No muscle and tendon shrinkage due to fixative solutions was observed with our fixation method. Pondering the organoleptic (color, appearance, consistency, odor, etc.) and biomechanical analyses (stiffness, Young's modulus, etc.), Thiel and SSS fixed cadavers are more suitable for purposes as surgical trainings and development of new surgical procedures. However, the change in the micro-anatomical structure of the muscles, especially with the Masson's trichrome staining, caused by these two solutions should not be overlooked.