Two novel graft techniques for rhinoplasty: Experimental study in A rabbit model

Introduction: Dorsum augmentation is one of the most challenging stages of rhinoplasty. Diced cartilage grafts used to correct nasal irregularities and augment the dorsum, have become quite popular recently. Many wrapping materials have been described in order to hold the diced cartilages together, to give the desired shape to the nose, to reduce the visibility and to increase the cartilage quality. Recent studies have shown that highly successful results can be achieved if the diced cartilages are wrapped in fascia. Dermis grafts can be an alternative to fascia because they can be taken in a shorter time and cause much less morbidity in the donor area. Despite a detailed literature review, we could not find any data on the diced cartilage wrapped in dermis. On the other hand although many autogenic tissues have been used as graft material in rhinoplasty, there is no study on the use of tendons. In this study, it was aimed to evaluate the viability and longevity of two new graft techniques defined by us for rhinoplasty; tendon graft as an alternative to cartilage graft and dermis graft to wrap the diced cartilages. Material and Method: Two lumbosacral fascias, a dermis graft, and a Achilles tendon were obtained from sixteen New Zealand white rabbits. After the right ear of the rabbits was amputated, the skin and perichondrium were removed. Ear cartilage and Achilles tendon were diced into 1 mm pieces. Four experimental groups were formed. In the first group, the diced cartilage grafts were not wrapped in any material (group A); in the second group, the diced cartilage grafts were wrapped in fascia (group B); in the third group, the diced cartilage grafts were wrapped in dermis (group C); in the fourth group, the diced tendon grafts were wrapped in fascia. Four subcutaneous pockets were created on the back of each rabbit and the grafts were placed in the pockets. After 16 weeks of observation, the rabbits were sacrificed and the grafts were removed. Since three rabbits died during the experiment, they were not included in the study (n=13). Macroscopically volume changes were measured and grafts' regularity were inspected. Then grafts were stained with Hematoxylin-Eosin, Masson trichrome and Van Gieson for histological examination. Results were evaluated at a P<0.05 significance level. Results: It was observed that all the grafts remained in the pockets where they were placed in 13 surviving rabbits and there was no total resorption in any of the grafts. A volume increase was detected in the groups of diced cartilage, diced cartilage wrapped in fascia, and diced cartilage wrapped in dermis, and there was no statistically significant difference when the volume changes of these three groups were compared. There was a little volume reduction in the diced tendon grafts wrapped in fascia, but this change was not statistically significant. Peripheral proliferation was higher in diced cartilage groups wrapped in fascia and dermis. Our histological analysis demonstrated that the amount of fibrosis, fragmentation and collagen fiber was higher, however the amount of elastic fiber content was less in the diced tendon grafts wrapped in fascia. There was no statistically significant difference between the groups in terms of other histological parameters. Conclusion: The result of our experimental study suggest that diced cartilage grafts wrapped in dermis and diced tendon grafts may be good alternatives for rhinoplasty operations particularly in the respect of dorsum augmentation. Further studies are required for clinical use of these techniques in human beings.