Laryngeal electromyographic changes in postthyroidectomy patients with normal vocal cord mobility

Area of Science:

• Otolaryngology
• Neurology
• Surgical Research

Background:

• Thyroidectomy is a common procedure for thyroid disease.
• Laryngeal nerve injury remains a risk despite surgical advancements.
• Subtle nerve damage may occur even with normal vocal cord appearance post-surgery.

Purpose of the Study:

• To investigate partial laryngeal nerve injury using laryngeal electromyographic analysis (LEMG) in post-thyroidectomy patients.
• To identify surgical and disease-related risk factors for these nerve injuries.
• To assess changes in LEMG findings in patients with normal vocal cord function after thyroid surgery.

Main Methods:

• Prospective study enrolling 32 patients undergoing thyroid surgery.
• Laryngeal electromyographic analysis (LEMG) performed preoperatively and at 1 and 3 months post-surgery.
• Evaluation of thyroarytenoid (TA) and cricothyroid (CT) muscles to assess recurrent and superior laryngeal nerves.

Main Results:

• Four patients showed preoperative mild-to-moderate partial LEMG changes.
• A statistically significant worsening of LEMG findings was observed in specific laryngeal nerves at 3 months post-surgery.
• No significant relationship was found between disease/surgery factors and the progression of LEMG findings.

Conclusions:

• This prospective study supports the risk of progressive laryngeal nerve injury after thyroid surgery, even with normal laryngoscopic examinations.
• LEMG can detect subtle nerve changes not apparent on standard vocal cord assessment.
• No reliable risk factors were identified to predict the progression of these LEMG changes.