Experimental study of free fat grafts in temporomandibular joint disc anchor

This study aims to evaluate the effect of using free fat grafts in preventing adhesion in the temporomandibular joint (TMJ) disc anchor and to observe the outcomes of free fat. Six 3-month-old mini-pigs were included in our study. The left joints were the experimental sides which had undergone releasing the anterior attachments, and free fat from the front of the ear lobe was grafted to the anterior gap. The right joints were the control group, where only the anterior attachments were released. MRIs were carried out and the maximal passive mouth openings were measured before operation, 3 months, and 6 months after operation. The joint tissues and fat specimens were excised after 3 and 6 months. The volume of fat was measured and hematoxylin and eosin (HE) staining was performed. Maximal passive mouth openings were analyzed with SPSS software package by Wilcoxon signed rank test. Maximal passive mouth openings were reduced gradually after 3 and 6 months, accompanied with the deviation of the mandible to the right side. There were significant differences between the 3 groups (P < 0.01). HE staining showed that the surface of the experimental joints was smooth while there was adhesion formation in the control joints. The volume of fat reduced respectively to 67.7% and to 42.6% after 3 and 6 months. HE staining showed new fat lobules were formed after 6 months with obvious fibrosis among the lobules. This study suggested that free fat can survive steadily 6 months after operation, with a surviving volume about 42.6% and it can also prevent adhesion formation in the TMJ disc anchor.