Silicone Oil Tamponade Hydrostatics and Technology for Additional Mechanical Support of Retina
Silicone oil tamponade is widely used in the surgical treatment of retinal detachments. The article provides analysis of mechanical forces exerted to the retina in various parts of the vitreous cavity. There are areas of tamponade effect insufficiency, in which it may be beneficial to create additional means which would support the retina keeping it attached to the pigment epithelium. The aim of the study was to develop a new technique desired to keep the retina attached in the areas where retina lacks effective tamponade effect of silicone oil. The technology is desired to be implemented in challenging cases of retinal detachments caused by giant retinal breaks, retinodialysis, or in patients with hard-to-remove epiretinal membranes in proliferative vitreoretinopathy. Materials and Methods. The proposed technique - magnetic scleral buckling - is able to exert pressure to the retina by the means of mutual magnetic attraction of the magnetic scleral buckle (outer buckle) sutured to the retina and endovitreal magnetic buckles (inner buckles) made of magnetoactive elastomer and placed onto the retina in the projection of the outer magnetic buckle. A series of ex vivo experiments was performed to elaborate the technique using isolated cadaver donor eyes: we performed magnetic scleral buckling and then subtotal vitrectomy with iatrogenic detaching of retina followed by implantation of endovitreal magnetic buckles (inner buckles) made of magnetoactive elastomers to provide additional mechanical support for the retina. Results. Elastic properties of the magnetic scleral buckles didn’t differ from those of common scleral buckles. Endovitreal magnetic buckles fitted well onto the retina, smoothly, tightly and effectively held it pressing against the pigment epithelium. We tried buckles of various sizes and shapes and chose the best fitted for endovitreal manipulations. Endovitreal buckles securely supported the retina and could be easily removed with 25G vitreotome. Conclusion. The developed technique of magnetic scleral buckling allowed to keep retina securely reattached with magnetic forces as was shown during ex vivo experiments. Further in vivo studies of the technique are required.