Surgical effects of various orbital decompression methods in thyroid-associated orbitopathy: Computed tomography-based comparative analysis

Objectives: To evaluate the surgical effects of orbital fat decompression and bony decompression in each orbital wall using computed tomography (CT) in thyroid-associated orbitopathy (TAO). Methods: In 27 TAO patients (48 orbits) with exophthalmos who underwent orbital wall decompression combined with fatty decompression, we recorded the resected orbital fat volume intraoperatively and estimated the decompression volume of the orbital wall in the deep lateral, medial and inferior walls using postoperative orbit CT images. Then, the correlation between exophthalmos reduction by Hertel reading and decompression volume in each area was analyzed to validate the surgical predictability, surgical efficiency and contribution level to total exophthalmos reduction. Results: The decompression volume in orbital fat and the deep lateral wall showed relatively high correlation with exophthalmos reduction (surgical predictability) compared to medial and inferior wall. The surgical efficiency was highest at deep lateral wall (2.704 +/- 0.835 mm/cm(3)), followed by medial wall (0.892 +/- 0.527 mm/cm(3)), orbital fat (0.638 +/- 0.178 mm/cm(3)) and inferior wall (0.405 +/- 0.996 mm/cm(3)). The actual contribution level to total exophthalmos reduction was highest in fatty decompression, followed by deep lateral decompression. Conclusion: In TAO patients with exophthalmos, orbital fat and deep lateral orbital wall are more predictable and contributory surgical targets for postsurgical exophthalmos reduction. (C) 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.