An Experimental Study Of The Influence On Thoracic Stability By Replanting The Small Blocks Of Autogeneic Cartilage

BackgroundAutologous costal cartilage is oftentimes harvested and used as scaffold in the rehabilitation and cosmetic surgeries. In some cases, like auricular reconstruction, multiple ribs on the both sides are harvested, resulting in reduced thoracic stability and impaired protection to the organs in the chest cage. In order to rehabilitate the abnormalities in the donor site, some scholars have proposed replanting costal cartilage debris back into the perichondrium pocket on the basis that the costal perichondrium and the joinction are reserved. However, there is no definite evidence whether replanting costal cartilage debris could improve the biomechanical properties of chest wall. ObjectiveTo build caprine animal model, which have similar costal cartilage morphology and constituent of human, of costal cartilage defect in thoracic cage. To investigate the mechanical properties of the thorax with autogeneic cartilage replanted back into the perichondrial pocket in situ by biomechanical experiments under standardized national criteria. Methods16 goats(8-12months) were randomly divided into 4 groups with 4 goats per group. The defects were made by removing the 7th, 8th and 9th cartilages while the perichondrium and the CCJ portions were remained intact. The defects were closed by 3 methods : suture perichondria only(negative control group), replanting the small blocks of autogeneic cartilage and suture the perichondria(group I), and filling the defects with bioprotein gel and cartilage debris mix followed by suture of perichondria(group II). The normal cartilages served as the normal control(normal control group). Morphologic observation, HE staining and biomechanical testing were performed on the cartilage samples harvested at 16 weeks postoperatively. ResultsThe overall morphology of the thorax in each group is good, with no collapse or angulation deformity observed in all experiment groups. The borders of costal and replanted cartilage were healed by fibroplasias. HE staining demonstrated that replanted cartilage survived well but without significant proliferation. Data of pressure, tensile, bending and impact tests were compared by one-way ANOVA and SNK test. P <0.05 was considered statistical significant among groups at inspection level α=0.05. Mechanical strength comparison result of 3 groups was group I﹥II﹥control. ConclusionReplanting autogeneic cartilage back into the perichondrial pocket in situ could improve thoracic cage mechanical properties by fibroplasias but not chondrocyte proliferation.