| dc.description.abstract | INTRODUCTION Benign and malignant thyroid diseases affect a large population worldwide.
Total Thyroidectomy is one of the most commonly performed intervention in general surgery. The
most feared and dangerous complication of thyroidectomy is the paresis or paralysis of the recurrent
laryngeal nerve (RLN). Therefore, endocrine surgeons have been prompted to include, among the
preoperative examinations, the evaluation of vocal cords function through flexible fiberoptic
laryngoscopy (FFL). RLN injuries have a low incidence in referral center with experienced
surgeons and, a routine FFL could be uncomfortable for patients and leads to unjustifiable increase
of health care costs. Transcutaneous laryngeal ultrasonography (TLUS) has been proposed as a noninvasive
and painless indirect examination of vocal cords function as alternative to direct FFL.
TLUS is an easy and feasible technique and is a non-invasive, inexpensive, rapid, painless,
repeatable and well tolerated by the patient. The aim of this study is to assess TLUS reliability as an
alternative method to direct FFL in the evaluation vocal folds function in patients candidate to
thyroid surgery.
MATHERIAL and METHOD We conducted a prospective observational multicentric cohort
study on 396 consecutive patients diagnosed with benign and malignant thyroid disease referred to
the Thyroid Surgery Division of the University of Campania "Luigi Vanvitelli" and to the General
and Specialistic Surgery Division of the “A. Cardarelli” Hospital. Patients were stratified into 2
groups according to BMI in a non-overweight group (BMI <25) and in an overweight or obese
group (BMI ≥25). Transcutaneous laryngeal ultrasonography was performed for each patients by
and experienced surgeon trained in ultrasound examination and, after TLUS, all patients underwent
routine preoperative FFL by a blinded experienced otolaryngologist. Findings were classified as
normal or impaired vocal cord function.
RESULTS Sensitivity was equal to 100% (98 – 100%), specificity was 99,5% (98 – 99,9%),
positive predictive value 66,7 % (61,8 – 71,3%), negative predictive value 100% (98 – 100%). The
probability of a vocal cord alteration in case of negative TLUS was 0% (0 – 10,4%) and if it
resulted positive was 66,7% (60,7 – 72,3%). In our series, no False Negative have been observed.
The prevalence of VCP in our series was 1% (0,3 – 2,7%). The results showed a concordance
between TLUS and FL of 99,5%, with a Cohen’s K value of 0,798.
DISCUSSION Thanks to the standardization of the ultrasound technique, we registered a high
overall assessability rate was 96.46%, a sensitivity of 100%, a specificity of 99.5%, a positive
predictive value of 66.7% and a negative predictive value of 100% in the identification of vocal
cords alterations. Our results showed a concordance between TLUS and FL of 99.5%, with a
Cohen’s K value of 0.798. These encouraging data allowed us to consider TLUS as part of the
routine preoperative screening, as it is absolutely reliable in identifying healthy patients without
paresis of the vocal cords. In case of doubts on the motility of the vocal cords, however, TLUS
allowed to select patients that should be addressed to FFL. Our study confirmed some difficulty in
identifying the vocal cords in male patients with hypertrophy of the thyroid cartilage without
calcification. This difficulty was solved thanks to adoption of a different acoustic window in lateral
approach, as our investigator had undergone specific training in ultrasound of the cervical region.
CONCLUSION TLUS is a valid non-invasive and painless alternative method in the preoperative
assessment of vocal cords for a selected population, such as pediatric patients, cardiopathic patients,
patients who do not tolerate invasive exams, patients with no diagnosis or suspicion diagnosis of
malignancy and patients who do not have voice changes. It could save a high percentage of patients
from FFL and in the same time could accurately select patients candidate to second level
examinations. [edited by Author] | it_IT |
