Comparative analysis of biomechanical properties of grafts and intact tunica albuginea in experiment

Kotov S.V., Sokolov N.M., Yapina A.A., Yusufov A.G., Titkova S.M., Klimenko E.I., Raksha A.P., Anurov M.V.

1) Pirogov Russian National Research Medical University, Moscow, Russia; 2) Moscow Multidisciplinary Clinical Center «Kommunarka» of the Moscow Department of Health, Moscow, Russia; 3) Pirogov City Clinical Hospital No. 1, Moscow, Russia

Introduction. Existing treatment methods for Peyronies Disease (PD) aim to restore the normal biomechanical functions of the tunica albuginea (TA); however, current data on biomechanical changes in PD, as well as on the biomechanical properties of native human TA, are extremely limited. The aim of our study was to evaluate the biomechanical properties of intact TA and the materials most commonly used for its replacement. Materials and Methods. Samples of the TA were collected from 9 male cadavers aged 20 to 65 years. Rectangular sections of the TA were excised from the dorsal surface of the corpora cavernosa. Fixation of the specimens in formalin was not performed, as this could affect the biomechanical properties of the tissue. Prepared samples were divided into longitudinal and transverse fragments. Pericardial grafts (allograft from cadaveric pericardium; xenograft from bovine pericardium) were prepared similarly. The obtained tissue fragments were subjected to mechanical testing. All tensile tests were conducted using a single-column universal material testing machine, the TA.XTplus Texture Analyzer (Stable Micro Systems Ltd., UK). Interactive stress-strain curves were used for result analysis. The following parameters were determined: stress, strength, strain, sample thickness. The obtained data were subjected to statistical analysis. Results. Analysis of the obtained data revealed that the stress and strength of longitudinal fragments of TA were statistically significantly higher (p=0,0004 and p=0,0008; Tukey’s test) than those for the transverse fragments. This indicates that human TA is anisotropic. Correlation analysis showed a negative correlation between the patient age and the strength (r=-0,49; p<0,05; Spearman’s rank correlation). Additionally, a negative correlation was found between the patient’s age and the thickness of their tunica albuginea (r=-0,56; p<0,05 according to Spearman’s test). When comparing human TA with grafts from bovine and human pericardium, it was found that the strength and thickness calculated for human tunica albuginea were statistically significantly higher (p=0,0001; Tukey’s test) than those for the grafts. Conclusions. Human and bovine pericardium grafts significantly differ from healthy TA in terms of stress, elastic modulus, strength, and thickness, which may impact the outcomes of surgical treatment for patients with PD.

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About the Authors

Corresponding author: N.M. Sokolov – postgraduate of department of Urology and Andrology, Institution of Surgery, Pirogov Russian National Research Medical University; urologist of Urology Division of Moscow Multifield Clinical Center «Kommunarka» of the Moscow Healthcare Department, Moscow, Russia; e-mail: 4eaman@gmail.com