Computed Tomographic Appearance of the Temporomandibular Joint in 1018 Asymptomatic Horses: A Multi-Institution Study.

The research article is based on a study conducted across multiple institutions, aiming to explore the variations in the temporomandibular joint (TMJ) in healthy horses, examine any associations with the patient’s age, breed, sex etc., and establish the common alterations in the TMJ using CT imaging.

Study Design and Objectives

• The researchers carried out a cross-sectional, retrospective study across eight separate veterinary hospitals, utilizing medical records of horses that had undergone head/neck CT scans but had shown no clinical indications of TMJ disease.
• The objectives were two-fold: First, to document anatomic variations of the TMJ found on CT scans in horses showing no symptoms of TMJ related diseases. Second, this study aimed to determine if these variations had any links to the horse’s age, breed, sex, the reason for CT examination, or the CT slice width.

Methodology and Results

• Various parameters like age, breed, sex, the reason for CT scan, and CT slice width data were recorded. Details like alterations in the shape and density of mandibular condyles, fossae, and intra-articular discs were taken note of for each horse.
• A sample size of 1018 horses was used for the investigation and modifications in the TMJ structures were found on CT scans in approximately 40% of these horses, and in 29% of the individual TMJ joints.
• The researchers utilized generalized logistic regression to analyze how these anatomical variations correlated with the age of the horses. Two age-related issues were identified. The horses that were under one year of age exhibited changes in the shape and density of the mandibular condyle. In contrast, elder horses were found to have certain spherical hypodensities within their mandibular condyles, implying the presence of bone cysts, as well as hyperdense areas within the intra-articular disc suggesting dystrophic mineralization.

Conclusions and Future Directions

• The findings brought forth by this study indicate that anatomic variations in the temporomandibular joints of horses are a common occurrence, even in the absence of any TMJ related disease symptoms. This observation held true for both younger and older horses.
• However, this study serves as an initial empirical investigation into these anatomical variations. For a more comprehensive understanding of the nature of these CT variations, additional studies incorporating techniques like gross pathology and histopathology are essential.