OBJECTIVES: The objective of this study was to evaluate the ability of a muscular index (Barrett's Index), calculated with multidetector computed tomography, to detect dysthyroid optic neuropathy in patients with Graves' orbitopathy. METHODS: Thirty-six patients with Graves' orbitopathy were prospectively studied and submitted to neuro-ophthalmic evaluation and multidetector computed tomography scans of the orbits. Orbits were divided into two groups: those with and without dysthyroid optic neuropathy. Barrett's index was calculated as the percentage of the orbit occupied by muscles. Sensitivity and specificity were determined for several index values. RESULTS: Sixty-four orbits (19 with and 45 without dysthyroid optic neuropathy) met the inclusion criteria for the study. The mean Barrett's index values (± SD) were 64.47% ± 6.06% and 49.44% ± 10.94%in the groups with and without dysthyroid optic neuropathy, respectively (p<0.001). Barrett's index sensitivity ranged from 32% to 100%, and Barrett's index specificity ranged from 24% to 100%. The best combination of sensitivity and specificity was 79%/72% for BI=60% (odds ratio: 9.2). CONCLUSIONS: Barrett's Index is a useful indicator of dysthyroid optic neuropathy and may contribute to early diagnosis and treatment. Patients with a Barrett's index >60% should be carefully examined and followed for the development of dysthyroid optic neuropathy.

OBJETIVO: Comparar os resultados da descompressão orbitária antro-etmoidal isolada àqueles da mesma cirurgia associada à remoção de tecido orbitário em paciente com orbitopatia distiroidiana seqüelar. MÉTODOS: Foram analisadas 2 modalidades de descompressão orbitária. Ambas tiveram como indicação apenas a correção estética e do desconforto ocular dos pacientes. Todos pacientes se apresentavam na fase inativa da orbitopatia distiroidiana. Em um grupo de 12 pacientes (grupo 2) foram realizadas 19 cirurgias de descompressão orbitária antro-etmoidal isolada. No outro grupo (grupo 1) composto por 8 pacientes foram realizadas 10 cirurgias de descompressão óssea antro-etmoidal associada à remoção de aproximadamente 1 centímetro cúbico de tecido adiposo da órbita. Os resultados das cirurgias nos dois grupos foram comparados entre si. RESULTADOS: No grupo 2 a redução da proptose oscilou entre 1 e 5 mm (média 3,68±1,10 mm) e no grupo 1 variou de 1 a 5 mm (média 3,25±1,36 mm). CONCLUSÕES: Tanto a descompressão óssea isolada como aquela associada à remoção de tecido adiposo orbitário apresentam redução semelhante na proptose, não havendo diferença significativa entre elas. A remoção de gordura temporal inferior, em torno de 1 centímetro cúbico parece não aumentar a redução da proptose quando comparada com a cirurgia descompressiva óssea isolada. Porém fatores como a complacência de tecidos moles, a quantidade de gordura retirada e as janelas ósseas realizadas em cada grupo devem ser considerados na conclusão deste trabalho retrospectivo de comparação entre técnicas.

PURPOSE: To compare the results of isolated antral-ethmoidal orbital decompression and that associated with orbital fat removal in patients with dysthyroid orbitopathy. METHODS: Nineteen isolated antral-ethmoidal orbital decompressions were performed in a group of 12 patients (19 orbits) with the diagnosis of dysthyroid ophthalmopathy in the quiescent stage. The same procedure, but in association with orbital fat removal, were performed in another group of 8 patients (10 orbits) also with the diagnosis of dysthyroid ophthalmopathy in the quiescent stage. The results of both groups were compared. RESULTS: In the first group the amount of retroplacement of the globe achieved 1-5 mm (mean 3.68±1.10 mm) and in the second group it achieved 1-5 mm (mean 3.25±1.36 mm). CONCLUSIONS: There was no significant difference between the results of the isolated antral-ethmoidal orbital decompression and that associated with orbital fat removal. The removal of 1ml of seems not to improve the retroplacement of the globe as an association with a 2-wall orbital decompression. However, many conditions must be considered to conclude any comparison between the two orbital decompression techniques, such as orbital soft tissue compliance, amount of fat removal and size of bone opening.