Quantitative Assessment of Orbital Decompression Surgery Using Photogrammetric Stereoimaging

Area of Science:

• Ophthalmology
• Plastic Surgery
• Medical Imaging

Background:

• Thyroid eye disease (TED) can cause proptosis and eyelid abnormalities.
• Bony orbital decompression is a surgical option to address these issues.
• Accurate volumetric assessment of periorbital changes is crucial for treatment planning.

Purpose of the Study:

• To quantify periorbital volume changes after bony orbital decompression in TED patients using stereoimaging.
• To compare these volumetric changes with Hertel exophthalmometry measurements.
• To independently assess upper and lower eyelid tissue volume changes.

Main Methods:

• Prospective study of adult patients with inactive TED undergoing bony orbital decompression.
• Quantitative photogrammetric stereoimaging (VECTRA M3 system) performed preoperatively and postoperatively (≥3 months).
• Calculation of periorbital, upper, and lower eyelid volumes; proptosis measured by Hertel exophthalmometry; correlation analysis performed.

Main Results:

• Bony orbital decompression led to significant reductions in periorbital volume (average 1.74-4.52 ml) and proptosis (average 3.6-9 mm) depending on decompression extent.
• A strong positive correlation was found between periorbital volume changes and Hertel exophthalmometry reduction (r = 0.713, p < 0.0001).
• Lower eyelid volume reduction did not significantly increase beyond two-wall decompression.

Conclusions:

• Graded bony orbital decompression effectively reduces both proptosis and eyelid tissue volumes in TED.
• Observed eyelid volume changes are important considerations for planning subsequent reconstructive eyelid surgery.
• These findings support the established sequence of thyroid periocular rehabilitation: decompression, strabismus surgery, then eyelid surgery.