Is it meaningful to preserve a palsied recurrent laryngeal nerve?

Surgeons may assume intuitively that preservation of a palsied recurrent laryngeal nerve (RLN) in patients with preoperative vocal cord paralysis is not meaningful. Here we present our experience in four cases with preoperative vocal cord paralysis, and show that preservation of a palsied RLN may be important in maintaining patients' voice.

Case 1 is a 54-year-old woman who suffered from a recurrent thyroid cancer disease and right vocal cord paralysis. She was subjected to resection of a locoregional lymph node metastasis on the right paratracheal groove. The right RLN was infiltrated by tumor and was sacrificed during surgery. Surprisingly, her voice weakened postoperatively. Evaluation of the patient showed immobility and mild atrophy of right vocal cord. Cases 2, 3, and 4 are patients with preoperative unilateral vocal cord paralysis and undergoing thyroid or parathyroid surgery. In these three patients, the palsied RLNs were identified and carefully preserved during surgery. These palsied RLNs and ipsilateral vagus nerves were tested with intraoperative neuromonitoring, and an evoked electromyographic activity was elicited. Postoperative evaluation of these three patients showed a steady state of voice and immobility without atrophy of vocal cords.

Even on a palsied RLN, a positive electrophysiological response may still be yielded by intraoperative neuromonitoring. This means that there may retain residual innervations in laryngeal muscles. To prevent atrophy of a paralyzed vocal cord, further injury to a palsied RLN should be avoided. Even the palsied nerve should be saved whenever possible.