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

Authors: O'Neill H D, Ballegeer E A, De Feijter-Rupp H L, Stick J A, Derksen F J, Robinson N E

Journal: Equine veterinary journal

DOI: 10.1111/evj.12105 PubMed: 23679063Log in to save

Summary

# Editorial Summary: Ultrasound-guided Biopsy of the Cricoarytenoideus Lateralis Muscle Recurrent laryngeal neuropathy (RLN) remains challenging to diagnose early, with current methods dependent on recognising clinical signs after substantial muscle degeneration has occurred; muscle biopsy could theoretically identify fibre-type changes characteristic of RLN before performance becomes compromised. Researchers developed and validated an ultrasound-guided biopsy technique for the left cricoarytenoideus lateralis muscle (CALM) in six standing horses, using a breast biopsy tool to harvest frozen tissue cores whilst monitoring for complications via endoscopy, ultrasonography and clinical examination over eight weeks post-procedure. Samples averaged 0.043 g and contained approximately 3,400 muscle fibres in cross-section, with no immediate complications, no significant endoscopic changes, and no alteration in muscle echogenicity between pre-biopsy and final assessment. The technique proved safe and well tolerated in healthy horses, establishing a minimally invasive method that could be applied in both research and clinical settings to potentially enable earlier RLN diagnosis through histological analysis of fibre-type composition before overt laryngeal dysfunction manifests. Whilst this proof-of-concept study was limited to healthy animals, the findings suggest this approach warrants further investigation in horses with suspected or confirmed RLN to determine whether early fibre-type changes can indeed be detected and whether such information would usefully inform prognosis or management decisions.

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Practical Takeaways

•A minimally invasive ultrasound-guided biopsy technique for laryngeal muscle is now available to identify fibre-type changes associated with RLN before clinical signs appear
•The technique is safe and well-tolerated in standing horses, making it suitable for both research and clinical diagnostic applications
•Adequate muscle samples (containing thousands of fibres) can be obtained reliably using a breast biopsy tool without causing detectable iatrogenic trauma

Key Findings

•Ultrasound-guided biopsy of the left cricoarytenoideus lateralis muscle was successfully performed in all 6 horses with no immediate complications
•Biopsy samples averaged 0.043 g and contained 3418 muscle fibres in cross-section (range 711-7143)
•No significant changes in laryngeal endoscopic grade occurred between pre-biopsy and 8-week follow-up
•Left CALM echogenicity remained significantly greater than right throughout the study with no difference between pre- and post-biopsy measurements

Conditions Studied

recurrent laryngeal neuropathy (rln)

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