Diagnosis of recurrent laryngeal nerve paralysis following esophagectomy by evaluating movement of the vocal cords and arytenoid cartilages using ultrasonography

Abstract
Advancements in thoracoscopic surgery have provided us with a deeper anatomical understanding of recurrent laryngeal nerve paralysis (RLNP), which is likely to occur after lymph node dissection. Taking a novel approach to researching the diagnosis of RLNP, we evaluated movement of the vocal cords and arytenoid cartilages using ultrasonography in patients who underwent thoracoscopic esophagectomy. RLNP occurred in six of the 24 patient cohort. The rate of hoarseness and difficulty in discharging sputum was significantly higher in the paralyzed group than in the non-paralyzed group. The diagnostic accuracy of RLNP by ultrasonography had a sensitivity of 83.3% (5/6), a specificity of 88.8% (16/18), a false positive rate of 5.6% (1/18), and a false negative rate of 0% (0/6). Although it is not completely accurate, our findings indicate that ultrasonography is quite effective for diagnosing RLNP, more so in combination with clinical symptoms. Ultrasonography may also be effective for identifying patients who are amenable to laryngoscopy for diagnosing RLNP, or for evaluating the recovery status of nerve paralysis.