Surgical Methods and Experiences of Surgeons did not Significantly Affect the Recovery in Phonation Following Reconstruction of the Recurrent Laryngeal Nerve

Abstract

Background: We reported phonatory recovery in the majority of 88 patients after recurrent laryngeal nerve (RLN) reconstruction. Here we analyzed factors that might influence the recovery, in a larger patient series.

Methods: At Kuma Hospital, 449 patients (354 females and 95 males) underwent RLN reconstruction with direct anastomosis, ansa cervicalis-to-RLN anastomosis, free nerve grafting, or vagus-to-RLN anastomosis; 47.4 % had vocal cord paralysis (VCP) preoperatively. Maximum phonation time (MPT) and mean airflow rate during phonation (MFR) were measured 1 year post surgery. Forty patients whose unilateral RLNs were resected and not reconstructed and 1257 normal subjects served as controls.

Results: Compared to the VCP patients, the RLN reconstruction patients had significantly longer MPTs 1 year after surgery, nearing the normal values. The MFR results were similar but less clear. Detailed analyses of 228 female patients with reconstruction for whom data were available revealed that none of the following factors significantly affected phonatory recovery: age, preoperative VCP, method of reconstruction, site of distal anastomosis, use of magnifier, thickness of suture thread, and experience of surgeon. Of these 228 patients, 24 (10.5 %) had MPTs <9 s 1 year after surgery, indicating insufficient recovery in phonation. This insufficiency was also not associated with the factors mentioned above.

Conclusions: Approximately 90 % of patients who needed resection of the RLN achieved phonatory recovery following RLN reconstruction. The recovery was not associated with gender, age, preoperative VCP, surgical method of reconstruction, or experience of the surgeon. Performing reconstruction during thyroid surgery is essential whenever the RLN is resected.

Fig. 1

Ansa cervicalis-to-recurrent laryngeal nerve anastomosis. Arrow indicates the anastomosis. CC the cricoid cartilage, Tr trachea, CCA common carotid artery, and IJV internal jugular vein. Head to the left

Fig. 2

Free nerve grafting. Arrows indicate two anastomoses. Head to the left

Fig. 3

Thyroid cancer invading the RLN at Berry’s ligament. Silicon rubber tubes are holding the central portion of the nerve (the left) and the distal portion of the nerve (the right) that was found through the laryngeal approach dividing the inferior pharyngeal muscle. Thy the thyroid, Es esophagus. Head to the right

Fig. 4

An ansa cervicalis-to-recurrent laryngeal nerve anastomosis was made following total thyroidectomy with central node dissection. Arrow indicates the anastomosis. The same patient shown in Fig. 3. Head to the right

Fig. 5

The MPTs of normal subjects, patients who had resection of the RLN without reconstruction, and patients who underwent reconstruction of the RLN. For the patients with RLN reconstruction, the MPT values 1 year after surgery are shown

Fig. 6

MFR values during phonation in normal subjects, patients who had resection of the RLN without reconstruction, and patients who underwent reconstruction of the RLN. For the patients with RLN reconstruction, the MFR values 1 year after surgery are shown

Fig. 7

MPT values at 1 year after surgery in the female patients according to the methods of the reconstruction of the RLN. DA direct anastomosis, ARA ansa cervicalis-RLN anastomosis, FNG free nerve grafting, VRA vagus-RLN anastomosis

Fig. 8

MPT values at 1 year after surgery according to the distal site of the anastomosis. Outside: the distal anastomosis was made outside of the thyroid cartilage; Inside: the distal anastomosis was made inside of the thyroid cartilage. The data are from female patients only

Fig. 9

MPT values at 1 year after surgery according to the surgeon who performed the reconstruction. ‘A’ to ‘K’ indicate the 11 experienced surgeons who had performed 10 or more RLN reconstructions, and ‘O’ indicates the group of 10 less-experienced surgeons who had performed less than 10 reconstructions