Ultrasound-guided biopsy of the cricoarytenoideus lateralis muscle: technique and safety in horses.

This study describes the development of an ultrasound-guided biopsy technique to safely test the cricoarytenoideus lateralis muscle (CALM) in horses. The goal is to potentially improve diagnosis of recurrent laryngeal neuropathy (RLN), a disease impacting horses, by identifying changes in the muscle before clinical symptoms show.

Research Goals

• The main objective of the study was to develop an ultrasound-guided biopsy technique for examining the left cricoarytenoideus lateralis muscle (CALM) in horses.
• The team was further aiming to evaluate the efficacy and safety of this method in a live setting. The goal was to potentially identify changes in fibre-type composition that indicate recurrent laryngeal neuropathy (RLN) before clinical signs become apparent.

Methods

• This was a longitudinal descriptive study involving six horses. The animals underwent ultrasound-guided biopsy of their left CALM while standing.
• Core samples of the muscle were obtained using a breast biopsy tool and frozen for analysis. The horses were subjected to serial endoscopic, ultrasonographic and physical examinations prior to and 8 weeks after the biopsy to check for trauma resulting from the procedure.
• The biopsied muscle core sections were analysed under a microscope to count the total number of muscle fibres obtained with each biopsy.

Results

• The data showed that there were no immediate complications from the biopsy procedure and the left CALM could be harvested successfully in all cases.
• The harvested biopsy samples had an average weight of 0.043g and contained an average of 3418 muscle fibres in cross-section.
• The laryngeal endoscopic grade (a measure of the health of the larynx) did not change significantly between the pre-biopsy stage and the end of the 8 week follow-up. This suggests the biopsy did not negatively impact the horses.
• The researchers found the left CALM had higher echogenicity (ability to reflect ultrasound waves) than the right CALM throughout the study. However, there was no difference in echogenicity between the prebiopsy CALM and the end of the study.

Conclusions

• Based on the research results, the authors concluded that ultrasound-guided biopsy of the left CALM is a safe and well-tolerated procedure that can provide a minimally invasive method to obtain muscle samples from healthy horses.
• It was suggested that this technique could have potential applications in both research and clinical settings, offering a new method for studying and identifying RLN in horses before clinical symptoms appear.