Retinal Coverage of Combined Intravitreal Tamponade Agents after Pars Plana Vitrectomy Visualized with Orbital Magnetic Resonance Imaging

PURPOSE: To characterize the behavior of single and combined intravitreal tamponade agents using magnetic resonance imaging (MRI), with emphasis on identifying the most effective materials and postoperative positioning strategies for complex retinal detachments involving both superior and inferior breaks. METHODS: Prospective observational study of adult patients undergoing pars plana vitrectomy. Following standard vitrectomy, patients received one of several tamponade agents: 24% or 25% sulfur hexafluoride (SF6), 18% perfluoropropane (C3F8), Siluron 2000, Densiron Xtra, or a Siluron/PFO combination. Postoperatively, MRI was performed in supine, prone, left lateral decubitus (LLD), and right lateral decubitus (RLD) positions to assess fluid-retina contact at anterior, mid-globe, and posterior slices. RESULTS: Six patients (mean age 62±5.6 years; 50% female) were included. Tamponade performance varied by both agent and head position. Pure Densiron achieved complete (360°) tamponade in supine position but showed residual fluid laterally and posteriorly. Gas tamponades (SF6/C3F8) demonstrated full 360° coverage in prone position but incomplete supine tamponade. Pure Siluron achieved stable anterior and mid-globe coverage but poor posterior tamponade. The Siluron/PFO combination provided complementary coverage patterns, achieving both superior and inferior tamponade in supine and prone orientations. No single material achieved uniform contact across all orientations. CONCLUSION: This MRI-based analysis reveals that tamponade effectiveness depends on both physical properties and patient positioning. Combined Siluron/PFO offered the most balanced coverage for complex detachments involving both superior and inferior pathology. These results support tailored tamponade selection and individualized postoperative positioning to optimize anatomic outcomes and potentially reduce the number of patients who may require adjunctive procedures such as scleral buckling.