Influence of Recurrent Laryngeal Nerve Transient Unilateral Palsy on Objective Voice Parameters and on Voice Handicap Index after Total Thyroidectomy (Including Thyroid Carcinoma).

Introduction: Total thyroidectomy (TT) is one of the most common surgical endocrine surgeries. Voice impairment after TT can occur not only in patients with recurrent laryngeal nerve (RLN) transient paralysis, but also in cases of normal vocal cord mobility. Aim: To compare voice limits using a speech range profile (SRP) in patients before and 14 days after TT and to investigate the influence of the early results of voice quality after TT on the personal lives of patients. We focused on the perception of voice change before and shortly after TT. Materials and methods: A retrospective study, in the period 2018-2020, included 65 patients aged 22-75 years. We compared two groups of patients: group I (n = 45) (without RLN paresis) and group II (n = 20) (with early transient postoperative RLN paresis). Patients underwent video flexible laryngocopy, SRP, and Voice Handicap Index-30 (VHI-30). Results: In group I, the mean values of Fmax (maximum frequency) and Imax (maximum intensity) decreased in women (both p = 0.001), and VHI-30 increased (p = 0.001). In group II after TT in women, the mean Fmax and Imax values decreased (p = 0.005 and p = 0.034), and the frequency range of the voice was reduced from 5 to 2 semitones. The dynamic range of the voice was reduced by 3.4 dB in women and 5.1 dB in men.VHI-30 increased (p = 0.001). Conclusion: The study documented a worsening of the mean values of SRP, VHI-30, and voice parameters of patients in group II. Voice disorders also occurred in group I without RLN paresis. Non-paretic causes can also contribute to voice damage after TT. SRP and VHI-30 are suitable tools for comparing voice status in two groups of patients, including those with dysphonia. Our data support the claim that the diagnosis of a thyroid cancer does not necessarily imply a higher postoperative risk of impaired voice quality for the patient.