A laryngoscope is a tool to view lesions in the throat. Doctors commonly use an electronic laryngoscope, which is a thin, flexible tube consisting of an electronic endoscope, a cold light source, and a photo-video system to find subtle lesions in hidden areas and to take biopsies. The test is safe and easy and can be done on an outpatient basis without hospitalization.
During the examination, the doctor removes the snot from your nose and sends the endoscope through the anterior nostril to the base of the nasal cavity and then slowly to the throat to look for lesions “along the way.
Patients with thyroid cancer have a laryngoscopy to look for invasion of the recurrent laryngeal nerve.
Preoperative laryngoscopy
About 6% of thyroid malignancies are significantly aggressive, invading surrounding tissues, especially the recurrent laryngeal nerve.
The doctor is doing a laryngoscopy before surgery to see if you have vocal cord paralysis, which is a sign of damage to the recurrent laryngeal nerve, which in turn indicates a highly aggressive and malignant tumor.
You may be thinking, “Isn’t vocal cord paralysis detected by changes in the voice? In fact, one study found that of the more than 300 patients with aggressive thyroid tumors who presented with vocal cord paralysis, only one third had voice changes.
If you already have hoarseness at the time of your visit, your doctor may recommend a preoperative laryngoscopy, not only to see the extent of tumor invasion, but also to help with intraoperative anesthetic intubation.
In addition to laryngoscopy, doctors sometimes use ultrasound and CT to look at the vocal cords. However, one study found that only 25% of patients with vocal cord paralysis were detected by CT. This suggests that CT is much less accurate than laryngoscopy in diagnosing vocal fold paralysis.
Postoperative laryngoscopy
Postoperative laryngoscopy
The chance of damage to the laryngeal recurrent nerve from thyroid cancer surgery is about 0.3% to 3.0%. This results in postoperative hoarseness and choking on water. However, it does not mean that whenever these symptoms are present, it is necessarily a retrolaryngeal nerve injury, but may also be related to intraoperative anesthetic cannula injury. At 6 months postoperatively, vocal cord function can return to normal in approximately half of patients.
So, your doctor may recommend laryngoscopy for some patients to clarify the laryngeal nerve injury.
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Co-written by Dr. Zheng Xiao Ke, Cancer Hospital of Fudan University