M2 ANATOMY

You are a medical student on an endocrine rotation within your surgical clerkship. Working with an experienced surgeon, you meet a 42-year-old woman. At her most recent yearly history and physical exam, a mass in the area of the thyroid gland was noted and biopsy revealed cancerous cells. The patient’s history reveals previous radiation treatment for throat cancer. The surgeon recommends a total thyroidectomy and explains that this will likely be a more difficult procedure due to the presence of scar tissue. In her preoperative laryngeal exam, her vocal fold function appears normal.

The day of the surgery, you are able to assist in the procedure. The surgeon cuts through and reflects a thin subcutaneous muscle layer then reflects two thin muscles overlying the thyroid gland. The surgeon begins dissecting the left lobe of the thyroid gland and isolates thyroid arteries and veins for ligation. Next, the surgeon moves to the right lobe of the thyroid gland, where scar tissue from the previous radiation is more abundant. To remove the thyroid gland from its attachment to the trachea and to protect nearby nerves, a resident surgeon retracts the large nerve in the tracheo-esophageal junction anteriorly. Through a difficult dissection, the surgeon finally removes the attachments and is able to locate and ligate the inferior thyroid artery in close proximity to the retracted nerve. Finally, the surgeon removes the entire thyroid gland.

The patient comes for post-operative checkup and mentions a slight change in her voice. Upon examination, her vocal folds do not appear symmetrical. Her right vocal fold, while it is moving, does not abduct or adduct fully. The surgeon refers her to a speech pathologist and explains that this is likely a temporary paresis due to traction injury of the nerve that serves laryngeal muscles.