Session: Poster session A

Surgical correlation proposal adapted for patients with graves orbitopathy submitted to strabismus surgery

Galton VASCONCELOS^1,2,3, Bárbara Guimarães LISBOA LIMA^1,2, Sebastián Enrique MENDOZA CARDOZO², Ana Rosa PIMENTEL FIGUEIREDO^1,2

¹Faculdade de Medicina da Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
²Hospital São Geraldo/HC - UFMG, Belo Horizonte, Brazil
³Instituto de Olhos de Belo Horizonte (IOBH) , Belo Horizonte, Brazil

Introduction: Graves' orbitopathy (GO) is a multifaceted disease, whose pathogenesis is not fully understood. Predicting results for strabismus surgery is challenging when conventional tables are used. The literature is scarce and there is no consensus on the techniques used.

Objectives: To verify a correlation between the deviation in prism diopters (PD) before and after surgery, on the first day and 6 months postoperatively and for each extraocular muscle (EOM).

Methods: This is an observational, retrospective study of patients diagnosed with GO submitted to strabismus surgery from 1990 to 2021 at a public university strabismus setting (P1) and in a strabismus sector from a private hospital (P2).

Results: 28 patients were included in the present study, 18 from P1 with ages between 24.0 - 86.0 yo (mean: 50.9 ± 13.0), and 10 from P2 aged 30.0 – 53.0 yo (mean: 43.8 ± 7.6). 66.7% were female and 33.3% male in P1, and 80% were female and 20% male in P2. The average of the medial rectus (RM) recess in the first surgery was 6.0 ± 6.8mm, of the lateral rectus (RL), was 0.5 ± 1.9mm, of the inferior rectus (RI) was 7.3 ± 3.6mm and of the superior rectus (RS) was 0.4 ± 1.5mm.

Statistically significant correlations (p < 0.05) were observed between mm of surgery for the medial rectus and the magnitude of the deviation in PD before and after the first surgical approach, on the first-day postop and 6 months postoperatively. In both situations, the correlation occurred directly (r > 0).

A measure that quantifies the accuracy and model quality of a linear regression is the Coefficient of Determination (R2). An R2 of 62.0% was observed. No statistically significant correlation (p ≥ 0.05) was observed in the study of the other EOM

Conclusions:

There was a correlation between the amount of strabismus surgery on the medial rectus in mm and the magnitude of the deviation in patients with GO. We could not find a correlation between the amount of surgery performed for other EOMs.