Proptosis Reduction by Clinical vs Radiological Modalities and Medial vs Inferomedial Approaches Comparison Following Endoscopic Transnasal Orbital Decompression in Patients With Dysthyroid Orbitopathy

IMPORTANCE Dysthyroid orbitopathy is clinically relevant in 30% to 40% of patients with Graves disease and is sight threatening as related to optic neuropathy, corneal breakdown, or both in 3% to 5%. OBJECTIVES To evaluate proptosis reduction using clinical (Hertel exophthalmometry) vs radiological (computed tomography) modalities and using medial vs inferomedial decompressions following the endoscopic orbital sling technique. DESIGN, SETTING, AND PARTICIPANTS Prospective study in an academic research setting between July 1, 2011, and December 31, 2012. Participants included 15 patients diagnosed as having dysthyroid orbitopathy with a Clinical Activity Score of at least 3 of 7 and disfigurement who did not respond to medical therapy or with a Clinical Activity Score of less than 3 of 7 and sight-threatening disease. INTERVENTIONS All patients underwent endoscopic decompression using an orbital sling technique. Preoperative and postoperative proptosis, visual acuity, perimetry, intraocular pressure, visual evoked potential, and fundus findings were measured by both clinical and radiological modalities and followed up to 3 weeks. MAIN OUTCOMES AND MEASURES Trends in proptosis reduction observed using both clinical and radiological modalities and medial and inferomedial approaches. RESULTS The mean Clinical Activity Score improved from 3.37 to 0.47 in 3 weeks. Both the visual acuity (4 of 6) and visual field (2 of 3) improved in 67% of patients, respectively. Intraocular pressure was reduced in all patients, without any observable changes in fundus findings, color vision, or visual evoked potential. The mean (SD) proptosis reduction was 3.41 (0.05) mm. Significant proptosis reduction (P < .005) was observed in the first and third postoperative weeks using clinical and radiological modalities. The paired P values achieved for proptosis reduction using Hertel exophthalmometry and computed tomography were not significant before or after surgery (P > .005). Performed separately, medial and inferomedial decompressions, respectively, achieved 6%(1.4 of 24.8 mm) and 10% (2.6 of 25.4 mm) proptosis reductions during the first week and 7%(1.8 of 24.8 mm) and 19% (4.8 of 24.8 mm) by the end of the third week. The observed paired P values for proptosis reduction by medial and inferomedial approaches were also not significant (P > .005). No postoperative complications were identified. CONCLUSIONS AND RELEVANCE Proptosis measurements by Hertel exophthalmometry vs computed tomography were comparable and equally effective. The inferomedial approach achieved more effective decompression than the medial approach alone. Compared with external and combined approaches, the endoscopic approach is a better and safer technique and is associated with low morbidity.