Postoperative laryngoscopy in thyroid surgery: proper timing to detect recurrent laryngeal nerve injury

There is currently a lack of consensus to support the proper timing for postoperative laryngoscopy that is reliable to diagnose recurrent laryngeal nerve palsy (RLNP) after thyroid surgery. The purpose of this study was to investigate the impact of different time intervals of fiber-optic nasolaryngoscopy (FNL) on the diagnosis of RLNP. FNL was performed postoperatively at day 0 (T1), at second day post-op (T2), and +2 weeks (T3). For patients with RLNP, repeated examinations were performed at +2 (T4), +6 (T5), and +12 months (T6). Four hundred thirty-four patients appear for postoperative FNL, providing 825 nerves at risk. Permanent RLNP occurred in 0.7%, temporary RLNP in 6.7%. RLNP rate was 6.4% at T1, 6.7% at T2, 4.8% at T3, 2.5% at T4, 0.8% at T5, and 0.7% at T6. Full recovery of vocal cord function was confirmed after rehabilitation in 87.5% of cases at T5 and 89% in T6. T2 was significantly superior to T3 in terms of diagnosis of RLNP (P < 0.05). Of patients at T2, 10.7% did not see any reason to FNL because of their normal voice register. FNL is essential for the detection of vocal cord paralysis after thyroidectomy. We report different time evaluation criteria of vocal cord motility with great and significant variability of results. Second day post-op inspection of the larynx (T2) is suggested. Symptomatic voice assessment is insufficient.