Retrobulbar Filling for Enophthalmos Treatment in Dogs: Technique, Description and Computed-Tomographic Evaluation....

A new therapeutic approach for enophthalmos may be retrobulbar lipofilling. This study aims to standardize the intraconal filling technique and to evaluate the degree of eyeball displacement by computed tomography (CT). Skull CT was performed on six dog cadavers before and after intraconal injection of two 5% iodinated, viscoelastic solutions, one per eye, using an ultrasound-guided supratemporal approach. The volume to be injected was calculated using formulas for retrobulbar cone anesthesia. After CT, the dogs underwent necropsy and histopathology to evaluate damages that eventually occurred to retrobulbar structures. Eyeball displacement was estimated using two CT-based methods, named M₁ and M₂. The Wilcoxon signed-rank test revealed no significant difference between the two injected materials in both M₁ (p > 0.99), and M₂ (lateral p = 0.84 and rostral p = 0.84 displacement). A statistically significant difference was found between the pre- and post-injection group M₁ (p = 0.002), M₂ (p = 0.004) for the lateral and (p = 0.003) for rostral displacement. Although the slight eyeball displacement, the retrobulbar filling can lead to enophthalmos resolution. Compared to M₁, the M₂ method has better-defined anatomical landmarks. Further, preclinical in vivo studies are necessary to assess retrobulbar filling efficacy and safety.