Laryngeal Nerve Protection Devices in Thyroid Surgery: A Systematic Review and Evidence Synthesis.
Daqi Zhang, Francesco Brucchi, Carla Colombo et al.
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In 30 seconds
This systematic review synthesized human studies of intermittent or semi-intermittent nerve-stimulation devices used for intraoperative neuromonitoring during thyroid and parathyroid surgery. Eleven observational studies included 7245 patients and 9186 nerves at risk. Across device categories, stimulation settings and pooled nerve amplitudes were broadly similar; once nerves were exposed, no clinically relevant differences in final recurrent laryngeal or vagus nerve amplitudes or latencies were observed. Evidence for stimulating dissecting instruments and attachable ring stimulators was limited.
Key findings
- Eleven observational studies covered 7245 patients and 9186 nerves at risk.
- Typical settings converged on 4-Hz square-wave pulses, pulse width around 100 μs, thresholds of 0.4-0.6 mA, and supramaximal currents of 1-2 mA.
- Pooled amplitudes were 700-800 μV for recurrent laryngeal nerves, 500-700 μV for vagus nerves, and about 270 μV for external superior laryngeal nerve branches.
- No clinically relevant differences in final recurrent laryngeal or vagus nerve amplitudes or latencies were observed among device categories after nerve exposure.
Why it matters
Intraoperative nerve monitoring devices are used to support nerve identification and assessment during thyroid and parathyroid surgery. This synthesis suggests that several device categories provide broadly comparable electrophysiologic performance once the nerve is exposed, while highlighting that evidence for some newer or alternative instruments remains sparse. These findings help frame device comparisons without establishing differences in clinical outcomes.
What to keep in mind
All included studies were observational, and evidence for stimulating dissecting instruments and attachable ring stimulators was limited.