Ex vivo study of vagal branches at risk for iatrogenic injury during laryngoplasty in horses.
Authors: Pisano Simone R R, Stoffel Michael H, Bodó Gábor
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Vagal Nerve Risk During Equine Laryngoplasty Laryngoplasty is a common procedure for horses with recurrent laryngeal nerve paralysis, yet the anatomy of vagal branches within the surgical field remains poorly characterised. Pisano and colleagues performed detailed dissections of nine equine specimens to map the location of pharyngeal plexus branches and cranial laryngeal nerve divisions, identifying structures within 5 mm of the surgical workspace as being at risk of iatrogenic injury. The pharyngeal plexus branch to the cricopharyngeal muscle was present in all nine specimens, whilst the external branch of the cranial laryngeal nerve consistently lay near the septum of the caudal constrictors—precisely where surgical incisions are made. Critically, tissue retraction alone compressed multiple vagal branches in the majority of specimens, and dorsolateral pharyngeal dissection or septal incision caused demonstrable damage to the external cranial laryngeal nerve in all nine cases and the cricopharyngeal plexus branch in seven of nine. These findings emphasise the anatomical vulnerability of multiple vagal structures during standard laryngoplasty techniques and suggest that refinements to retraction methods and dissection planes warrant investigation to reduce postoperative complications such as dysphagia, oesophageal dysfunction, or incomplete vocal fold mobilisation that may result from unrecognised nerve injury.
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Practical Takeaways
- •Dorsolateral pharyngeal dissection and septum incision during laryngoplasty carry high risk of damaging the external cranial laryngeal nerve—modify surgical technique or use alternative approaches where possible
- •Gentle retractor placement and minimal retraction force are critical as the retractor blade directly compresses multiple nerve branches in all cases
- •Consider anatomical variation between individuals; some vagal branches were inconsistently present, so intraoperative identification and careful dissection around suspicious structures is essential
Key Findings
- •The external branch of the cranial laryngeal nerve (ebCLN) was identified in 100% of specimens and was harmed during dorsolateral pharyngeal dissection in 9/9 specimens
- •Tissue retractor blade compression affected the internal branch of the cranial laryngeal nerve (ibCLN) in 6/6 specimens and pharyngeal plexus branches in 6/6 specimens where identified
- •Surgical incision of the septum of the caudal constrictors posed risk to ebCLN (9/9), cricopharyngeal branch (7/9), and thyropharyngeal branch (4/8) of the pharyngeal plexus
- •Multiple vagal nerve branches are consistently located within the laryngoplasty surgical field at risk of iatrogenic injury