Abstract
Purpose: :
Surgical rehabilitation of thyroid orbitopathy patients involves reducing proptosis, treating strabismus and lengthening the lids. Not all are necessary in each patient, however they often are. The current investigation intends to describe post decompression changes that may influence the staging of these procedures, and/or their possible combination into single operative events.
Methods: :
In this retrospective cohort study, records of 169 patients who underwent orbital decompression were reviewed. All measurements were made by a single orbital specialist (JR). Time to follow up was defined as the most recent follow up after decompression and prior to any secondary procedures. No strabismus or lid surgery was performed at the time of decompression. Strabismus was measured with alternating prism cover test. Ductions were estimated utilizing Hirschberg's method. Exophthalmometry was measured with Hertel. Lid positions were defined relative to the pupillary light reflex. Strabismus data was analyzed within eye pairs. Ductions, exophthalmometry and lid position were analyzed by eye. T-test for paired data was utilized to compare means pre and postoperatively.
Results: :
Study population was on average 45 years old and 73.4% female. Average length of follow up was 1.3 years. Esotropia was significantly increased after decompression by an average of 8.1 prism diopters (PD) (p<0.001). Worsening of esotropia by greater than 10 PD was found in 36.5 % of patients. Exotropia and vertical deviations were not significantly altered. No ductions were significantly altered post decompression surgery. Similarly, upper lid retraction remained unchanged. Exophthalmometry improved by a mean (SD) of 3.8mm (2.8) (p<0.001) and this result was correlated with the number of walls removed (Pearson’s r=-0.302, p<0.001) and lower lid retraction also improved by 50% from 1.4mm to 0.7mm (p<0.001). Improvement in lower lid retraction was found in 51.0% of patients.
Conclusions: :
On average, esotropia tends to worsen with decompression surgery, while ductions are unaffected. This result supports the clinical dictum to avoid strabismus surgery until after decompression. The improvement in lower lid retraction suggests that at least lower lid lengthening surgery should be reserved for after decompression, as there may be significant spontaneous improvement.
Keywords: orbit • eye movements • strabismus