Morphological Facial Changes after Modified Medial Canthoplasty (Saito Method) in Brachycephalic Dog Breeds

Abstract

The medical records of brachycephalic dog breeds that underwent the modified medial canthoplasty (MMC-Saito method) between May 2021 and December 2022 were retrospectively reviewed. The recorded pre- and post-operative distance from the medial palpebral commissure to the inferior lacrimal punctum (DIP), distance from the medial palpebral commissure to the superior lacrimal punctum (DSP), DIP to DSP ratio (DIP/DSP), distance from the medial palpebral commissure to the nasal skin fold (DMNF), distance from the medial palpebral commissure to the nasal alar (DMN), and palpebral fissure width (PFW) were reviewed and compared. Medial entropion was also evaluated pre-operatively and at the post-operative follow-up visits. The study included 54 eyes from 32 dogs. The mean (± standard deviation) pre-operative DIP/DSP, DMNF, DMN, and PFW values were 2.26 ± 0.51, 3.3 ± 1.7 mm, 18.5 ± 4.4 mm, and 22.4 ± 2.0 mm, respectively, and the post-operative values were 1.02 ± 0.10, 6.9 ± 1.3 mm, 21.3 ± 4.8 mm, and 19.6 ± 1.8 mm, respectively. All parameters significantly differed pre- and post-operatively (P <0.01). Medial entropion improved post-operatively in 38 of the 38 eyes (the medial entropion area photographs were available in 38 of 54 eyes, for pre- and post-operative follow-up of over 1 month). These results suggest that the MMC-Saito method may release upper eyelid retraction, reduce the PFW, and extend the DMNF and DMN.