Vocal fold palsy (VFP) is the most common source of claims following thyroidectomy, with no established predictive factors for recovery. We evaluated the prognostic role of intraoperative neuromonitoring (IONM) and post-operative (PO) flexible fiberoptic laryngostroboscopy (FFL) findings.

During 3125 IONM-assisted thyroid procedures (April 2021-April 2023), 5699 nerves at risk (NAR) were evaluated. All losses of signal (LOS) were prospectively registered. After LOS findings, FFL was performed 1,15,45 and 180 days after surgery (POD). Patients were categorized into two groups basing on vocal fold motility (VFM) at POD180: recovery group (RG) and non-recovery group (NRG).

Among 105 included patients (3.36% of all the patients, 1.8% of NAR), 89 recovered VFM within POD180, while 16 (15.2% - 0.5% of all the patients, 0.3% of NAR) did not. Type II LOS and arytenoid motility (AM) at POD15 were significantly more frequent in the RG Vs NRG (61.7%Vs12.5% and 71.9Vs25%, respectively) (p=0.005 and p=0.001, respectively). Conversely, arytenoid inward rotation (AInR) at POD15 was significantly more frequent in NRG (87.5%Vs6.75%) (p=0.001). Type I LOS, arytenoid fixation and AInR at POD15 resulted in no recovery in all the cases, while Type II LOS, AM and no AInR at POD15 resulted in recovery of VFM in all the cases (p=0.001).

Type of LOS and arytenoid characteristics at POD15 significantly influenced VFM recovery. AInR was a strong predictor of non-recovery, while type II LOS and POD15 AM predicted recovery. This information should be included in follow up protocols for clinical and medico-legal purposes.