Paclitaxel inhibits post-traumatic recurrent laryngeal nerve regeneration into the posterior cricoarytenoid muscle in a canine model

Hyperthermal liquid, spray, and smog may be potential risk factors for recurrent laryngeal nerve thermal injury during thyroid surgeries

PURPOSE

The hyperthermal liquid, spray and smog caused by energy-based surgical devices (EBDs) may be the potential risk factors for recurrent laryngeal nerve (RLN) thermal injury, but not been reported previously. We aim to demonstrated it both in thyroid surgeries and animal experiments.

METHODS

321 thyroid patients and 32 rats were divided into two groups respectively. A type of endoscopic gauze was implemented in the protected group to prevent nerve from thermal risks. Electromyography and laryngoscope were recorded to determine nerve's conductive ability. Microstructural morphological damage to nerves and muscles were evaluated by light and electron microscopy in the animal experiments.

RESULTS

After thyroid surgeries, the incidence of transient vocal cord (VC) palsy was decreased in the protected group (1.4%) compared with the conventional group (4.7%) (P = 0.037). In animal experiments, the average nerve conductive velocity was significantly decreased in the conventional group (5.8 ± 2.1 vs. 25.5 ± 4.7 m/s, P < 0.01). Typical acute morphological thermal changes of edema, coagulation and homogenization in nerve tissues were recorded by light microscopy in the conventional group. Four weeks later, the average weight of gastrocnemius muscles in the injured limb was significantly decreased (1.3 ± 0.2 vs. 2.2 ± 0.2 g, P < 0.01), while no significant difference was noted in the protected group (2.0 ± 0.3 vs. 2.3 ± 0.4 g, P = 0.61).

CONCLUSIONS

Hyperthermal liquid, spray or smog may represent risk factors contributing to RLN thermal injury caused by EBDs. Damage to the nerve's conductive ability and morphological changes in nerves and muscles likely represent typical responses to thermal injury. Implementation of endoscopic gauze may be a promising method to protect the RLN from thermal damage especially in endoscopic thyroid surgeries.

Animal Models for Dysphagia Studies: What Have We Learnt So Far

Research using animal models has contributed significantly to realizing the goal of understanding dysfunction and improving the care of patients who suffer from dysphagia. But why should other researchers and the clinicians who see patients day in and day out care about this work? Results from studies of animal models have the potential to change and grow how we think about dysphagia research and practice in general, well beyond applying specific results to human studies. Animal research provides two key contributions to our understanding of dysphagia. The first is a more complete characterization of the physiology of both normal and pathological swallow than is possible in human subjects. The second is suggesting of specific, physiological, targets for development and testing of treatment interventions to improve dysphagia outcomes.