Orbicularis Oculi Muscle morphometry alterations in Hemifacial Spasm

Abstract

Purpose : Despite being phenotypically normal, the nonaffected side of hemifacial spasm patients (HFS) may have characteristic histopathological findings. This study focuses on objectively evaluating orbicularis oculi muscle (OOM) samples from patients with HFS and control subjects who underwent cosmetic blepharoplasty.

Methods : 21 OOM samples were included in this study. 7 samples from 4 normal control subjects and 7 paired eyelids (7 from the affected and 7 from the nonaffected side) from patients with HFS, virgin of treatment, were evaluated. OOM samples were prepared using Hematoxylin and Eosin (H&E) and Gomori staining. High-resolution slide photos (x400) were obtained. Image parameters were quantitatively analyzed using ImageJ by a blind expert operator. Outcomes were area of each fiber (calculated in H&E staining) and percentage of connective tissue (assessed in Gomori staining). T-student tests and paired-t test were used to compare measurements between groups.

Results : Both the nonaffected side (13.46 ± 1.59 mm²) and the affected side (12.64 ± 3.10 mm²) of HFS patients presented greater fiber size than the control group (9.03 ± 1.76 mm²), p<0.01 and p=0.02, respectively. No statistically significant difference was observed between the paired sides of the patients. The affected HFS-OOM revealed increased connective tissue (28.76 ± 8.11%) than both the nonaffected (20.07 ± 9.04%) and control-OOMs (14.12 ± 5.38%), p=0.02 and p<0.01, respectively. No difference was detected between the control and the nonaffected group. Results presented as mean ± SD.

Conclusions : There are interesting and significant morphometric differences in the OOM of both nonaffected and clinically affected sides of patients with HFS that may reflect homeostasis disturbances due to the facial movement disorder.

This is a 2021 ARVO Annual Meeting abstract.

 

Illustrative light microscopy images of orbicularis oculi muscle from controls and patients with hemifacial facial both nonaffected and clinically affected sides. H&E and modified Gomori Trichrome Stains, x400.