A Surgical Mouse Model for Advancing Laryngeal Nerve Regeneration Strategies.
Alexis Mok, Jakob Allen, Megan M Haney and 12 others
PMID 31388736WHAT IT FOUND
In mice, cutting the recurrent laryngeal nerve caused lasting vocal fold immobility and brief swallowing changes.
Vagus nerve stimulation after nerve crush showed preliminary signs of faster vocal fold recovery.
Key findings
01Unilateral recurrent laryngeal nerve transection in mice caused immediate same-side vocal fold immobility, and that immobility was still present at 1 week and 3 months.
02Swallow function showed only acute differences after surgery; by 3 months no significant differences remained, and all penetration-aspiration scores were 1.
03In the 6-mouse crush feasibility comparison, vagus nerve stimulation was associated with a higher vocal fold mobility score at 12 weeks than no stimulation, but the paper says the sample was too small for rigorous statistics.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The work was done in mice, not in people. It does not test human vocal fold paralysis or swallowing. Six of the 50 mice died during surgery, including both bilateral recurrent laryngeal nerve transection mice, so some groups were very small. The intraoperative vagus nerve stimulation comparison had only 3 treated and 3 untreated mice, and the paper says the small sample precluded rigorous statistical analyses. Videofluoroscopy was not performed in the crush and stimulation group, so swallowing outcomes were not tested there. Vocal fold mobility was scored by eye on a 3-point scale, which can be subjective. The study did not measure voice, breathing, or laryngeal muscle electrical activity, and it did not explore sex differences. Some swallowing measures could not be used because groups differed before surgery. Mice did not show penetration or aspiration. Mouse swallowing anatomy may limit comparison with humans.
Declared interests
The authors declared no potential conflicts of interest. The article is listed as NIH extramural research support.
The easy way to misread this
Do not treat intraoperative vagus nerve stimulation as a proven treatment for vocal fold paralysis. It was tested only in a 6-mouse feasibility study, with 3 treated and 3 untreated mice compared, and the paper says the small sample precluded rigorous statistical analyses.