Use of human nail for reconstruction of the orbital floor: an experimental study in rabbits.

The orbital floor is the thinnest part of the orbital wall, and in 20% of all maxillofacial injuries it is fractured. Autografts, allografts, and alloplastic materials are used in reconstruction, but there is no consensus about which material is the most appropriate. Nail is a semirigid material that is easy to reshape and is not antigenic. Alloplastic materials, which are used in reconstructions of the orbital floor, have various complications and are expensive. Autografts have donor-site problems, high rates of resorption, and take a long time to do. We created bilateral 10mm defects in the orbital floors in 18 New Zealand rabbits. We reconstructed the left orbital floors with double-ground human nail while the right orbital floors were left open as controls. The orbital floors were examined macroscopically and microscopically at 4, 8, and 12 weeks postoperatively, and there were no macroscopic signs of infection, inflammation, or extrusion. Forced duction tests showed that it was possible to induce movement of the eyeball for all 18 of the reconstructed sides throughout the observation period, and in 14 of the 18 rabbits on the control sides. Positive forced duction test shows us that orbital muscles are trapped in orbital floor defect and due to this movement of eyeball is restricted. Acute and chronic inflammation, fibrosis, vascularisation, and the presence of foreign body giant cells were evaluated microscopically. Acute inflammation and the presence of foreign body giant cells were recorded as mild, whereas fibrosis, chronic inflammation, and vascularisation were severe, as were epithelialisation on the maxillary sinus side of the nails, calcification, and progression of collagen. We found no signs of resorption of the nails.