During thyroid surgery, doctors often face a silent risk: recurrent laryngeal nerve damage. This nerve, only about 2mm thick, affects our voice and respiratory function. Damage can lead to hoarseness or even suffocation. The advent of recurrent laryngeal nerve monitors, like a "detector" during surgery, significantly reduces these risks. Let's learn more about recurrent laryngeal nerve monitors today.
Ⅰ. What is recurrent laryngeal nerve monitoring?
A recurrent laryngeal nerve monitor is an electronic device that tracks nerve function in real time. Its core principle is "nerve electrical signal transmission":
How it works:
The recurrent laryngeal nerve monitor consists of a probe, electrodes, a monitor, and wires. Before surgery, the electrodes are placed near the patient's vocal cords, ensuring full contact with them. During surgery, the probe sends a weak current (usually 0.5-1 mA) to the nerve.
If the current stimulates the nerve, it triggers muscle contraction, generating electromyographic signals.
The electrodes capture the signal from the vocal cords and convert it into an audible beep (a "beep"), while a waveform is displayed on the monitor, alerting the doctor, "Here's the nerve!"
Ⅱ. How to Use a Recurrent Laryngeal Nerve Monitor?
Nerve monitoring is accomplished in four steps, using a standard thyroid surgery as an example:
1. Preoperative Preparation
After general anesthesia, an endotracheal tube with electrodes is inserted into the trachea, ensuring good contact between the electrodes and the vocal cords.
2. Initial Testing
Before surgery begins, the nerve is stimulated and a baseline signal is recorded (to confirm proper function of the device and intact nerve function).
3. Intraoperative Monitoring
With each step, the physician gently touches the suspected tissue with a probe. If a beep is heard, the recurrent laryngeal nerve is likely nearby. Caution is required, and careful dissection is performed to promptly identify the nerve and avoid damage.
4. Completion Verification
At the end of surgery, another test is performed to confirm intact nerve function.
Ⅲ. What are the advantages of using a recurrent laryngeal nerve monitor?
Reducing the risk of recurrent laryngeal nerve injury: In previous thyroid surgeries, the surgeon relied on experience to visually identify the nerve (only 2-3 mm in diameter), resulting in an injury rate of approximately 3%-8%. With the use of a monitor, this injury rate has been reduced to less than 1%. (A 2024 study from Peking Union Medical College Hospital showed that the rate of postoperative vocal cord paralysis in patients undergoing thyroid cancer surgery who used a recurrent laryngeal nerve monitor was only 0.6%, compared to approximately 5.2% in the group without a monitor.)
The use of a recurrent laryngeal nerve monitor also plays an important role in safeguarding laparoscopic thyroid surgery.
Locates varicose recurrent laryngeal nerve: Approximately 15% of patients have varicose recurrent laryngeal nerves (such as those that pass through the thyroid gland or enter the larynx directly from outside the thyroid gland), which are difficult to detect with the naked eye. The monitor can detect these varicose nerves in real time, reducing the difficulty of dissection and the risk of injury.
Shortening surgical time: The surgeon no longer needs to repeatedly dissect the nerve to locate it, shortening the surgical time and making it particularly suitable for complex secondary surgeries.
The recurrent laryngeal nerve monitor is more than just a tool; it revolutionizes surgical philosophy-it shifts surgery from one based on experience to one based on objective quantification, prioritizing both protective function and lesion removal. As the technology becomes more widespread and device prices decrease, it may become standard equipment for thyroid surgery, protecting the voices and breathing of even more patients and making thyroid surgery more precise and safer.