Facial Paralysis Management: comparison among available surgical procedure for upper lid loading and proposal of customized 3D implant.

In case of facial palsy with long standing lagophtalmos and chronic corneal exposure,upper lid implant (“lid loading”) represents an effective and helpful procedure. The aim of the study was to plan an innovative lid loading”, developing a technical refinement both of the shape and material of the lid implant, as well as of the surgical technique.
To address these issues, the use of a direct CAD/CAM procedure with the manufacture of a custom-made implant through direct metal laser sintering has been introduced (DMLS). This technology is able to reproduce carefully the spherical curvature conforms to the shape of the ocular globe fitting on the 3D customized model based on contralateral upper lid CT based anatomy. The ideal anatomical eyelid implant should have a curved shape fitting perfectly to the anatomical curvature and to the eyeball size, respecting the patient’s proper morphology and a calibrated weight distribution, to avoid rotation, migration or inversion of the implant. Regarding innovation in the material, our choice was addressed on CobaltChrome SP2 (Super Metal Alloy); this metal alloy has many advantages in comparison to the traditional gold and platinum. It is biocompatible, amagnetic, stainless, white shiny color, (similar to platinum and for that not visible under the eyelid), without impurities, cost saving in comparison to gold and even more to platinum. The bio-model of the actual upper eyelid was manufactured directly using a 3D soluble support technology rapid-prototyping machine. Moreover, to avoid the most common complications of the traditional surgical approach, we modified also the surgical technique in the respect of anterior levator muscle fibers. 
 The results of our primary applications in vivo have shown that the development of new biocompatible materials and a customized planning, led to satisfactory results (in term of compliance, tolerability, complications, costs) compared with traditional and standardized devices.