J Korean Ophthalmol Soc.  2014 Sep;55(9):1267-1271. 10.3341/jkos.2014.55.9.1267.

Orbital Morphology for Decompression Surgery in Thyroid Eye Disease Using 2-D Orbital CT and 4 Parameters

• Lee JS
• Lee H
• Chang MW
• Baek S
• Lee TS

• KMID: 2217107
• DOI: http://doi.org/10.3341/jkos.2014.55.9.1267

Abstract

PURPOSE
To present easily measurable 2D orbit computed tomography (CT) reference data that can be used in a preoperative study for orbital decompression and classification of individual orbital morphologies.
METHODS
The study sample was composed of 77 patients with orbital contusion (42 Asian males + 35 Asian females = 154 orbits) who visited the emergency room of the Korea University Guro Hospital from September 2012 to June 2013. Patients with orbital wall fracture, retrobulbar hemorrhage, or eyeball rupture were excluded. Medical records including 2D orbit or facial bone CT were retrospectively reviewed and 4 orbital parameters (orbital length, OL; globe length, GL; GL/OL ratio and 2D cone angle) were measured.
RESULTS
The average OL was 42.53 +/- 2.46 mm (35.63-49.09 mm) and average GL was 24.83 +/- 1.09 mm (22.75-28.13 mm). The average GL/OL ratio using these 2 parameters was 0.59 +/- 0.04 (0.50-0.68). The posterior cone angle was on average, 45.96 +/- 5.91degrees (29.35-60.04degrees).
CONCLUSIONS
Simple measurement of 4 parameters using 2D orbit CT and classification of Asian individual orbital morphology may help in the choice of the most effective surgical technique for decompression surgery in thyroid eye disease patients.

Keyword

2D orbit CT; Orbital decompression surgery; Orbital morphology; Orbital parameter; Thyroid eye disease

MeSH Terms

Asian Continental Ancestry Group
Classification
Contusions
Decompression*
Emergency Service, Hospital
Eye Diseases*
Facial Bones
Female
Humans
Korea
Male
Medical Records
Orbit*
Retrobulbar Hemorrhage
Retrospective Studies
Rupture
Thyroid Gland*

Figure

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  Figure 1. Globe length: antero-posterior globe length measured at the optical lens level.

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  Figure 2. Orbital length: antero-posterior orbital length defined by the distance between orbital apex and the middle of the anterior orbital boundary line. The measurement was performed at the level of the inferior end of the superior orbital fissure.

• 

  Figure 3. Cone angle: cone angle, defined by the angle between the medial and lateral orbital wall. The measurement was performed at the level of the optic canal.

• 

  Figure 4. Distribution of orbital length.

Reference

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