Results of recession inferior rectus muscle in patients with Thyroid eye disease

Relevance In endocrine ophthalmopathy (EOP), the inferior rectus muscle (IRM) is most often involved in the inflammatory process, which leads to hypotropia, limited upward eye mobility, and constant binocular double vision. IRM recession is the first stage of surgical treatment of restrictive strabismus. However, the lack of standardized techniques and differences in the dosage of the volume of surgical intervention make it difficult to choose the optimal surgical strategy and predict the results. Analysis of changes in the angle of hypotropia in the postoperative period will allow us to evaluate the effectiveness of surgery and reduce the risk of overcorrection or undercorrection of vertical strabismus in patients with EOP [1–3]. Objective To evaluate the results of inferior rectus muscle recession in patients with endocrine ophthalmopathy at different stages of postoperative observation. Material and methods The study included 37 patients with an inactive phase of EOP and IRM damage according to multispiral computed tomography of the orbits. All patients underwent recession with extension of the NPM using "distance" sutures. The hypotropia and excyclotropia angles were measured using the Inami synoptophore (Japan) before surgery, on the 1st and 7th days, 2-3 and 5-6 months after surgery. Results The study showed a significant decrease in the degree of hypotropia and excyclotropia after the surgery. Before surgery, the average hypotropia angle was 18.5 degrees (from 10 to 33 degrees), and the excyclotropia angle was 6.5 degrees (from 2 to 12 degrees). On the 1st day, the average hypotropia angle was 10.6 degrees (from 4.5 to 23 degrees), the average excyclotropia angle was 2 degrees (from 0 to 5 degrees); On the 7th day, the average values ​​of the hypotropia and excyclotropia angles were 7.5 degrees (from 0 to 19 degrees) and 1.5 degrees (from 0 to 4 degrees), respectively. 2–3 months after the operation, the average values ​​of the hypotropia and excyclotropia angles were 5.5 (from 0.5 to 17.5 degrees) and 0.5 degrees (from 0 to 2 degrees), respectively. Further observation at 5–6 months revealed an insignificant change in the degree of hypotropia: the average value was 4.5 degrees (from 0.5 to 15.5 degrees), and the average value of the excyclotropia angle remained the same – 0.5 degrees (from 0 to 2 degrees). Conclusion The data obtained as a result of the study indicate that in patients with restrictive hypotropia associated with EOP, after recession of the inferior rectus muscle with its lengthening by means of “distance” sutures, the angle of hypotropia and excyclotropia decreases gradually, reaching the maximum effect of the intervention by the 3rd month after surgery. Keywords: endocrine ophthalmopathy; strabismus; hypotropia; recession of the inferior rectus muscle