Visualization Versus Neuromonitoring of the External Branch of the Superior Laryngeal Nerve During Thyroidectomy.
Visualization Versus Neuromonitoring of the External Branch of the Superior Laryngeal Nerve During Thyroidectomy.
Injury to the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy
 results in lowered fundamental frequency of the voice and worsened voice performance in
 producing high-frequency sounds. It remains unclear if use of intraoperative nerve monitoring
 (IONM) can improve clinical outcome of thyroidectomy in terms of preserved individual voice
 performance. This study was designed to test that hypothesis.
Phonation changes following thyroidectomy have been reported in many investigations. They are
 considered to be multifactorial in origin and can be a consequence of laryngeal nerve injury
 or other events during thyroidectomy including arytenoids trauma after endotracheal
 intubation, cricothyroid dysfunction, strap muscle malfunction or lesion of the perithyroidal
 neural plexus, laryngotracheal fixation with impairment of vertical movement and
 psychological reaction to the operation. Injury to the external branch of the superior
 laryngeal nerve (EBSLN) can occur during the dissection and clamping of the superior thyroid
 vessels and the prevalence of this complication has been reported from 0.5% to 58%. This
 injury causes a complete paralysis of the cricothyroid muscle which results in lowered
 fundamental frequency of the voice and worsened voice performance in producing high-frequency
 sounds. Intraoperative nerve monitoring (IONM) has gained widespread acceptance as an adjunct
 to the gold standard of visual nerve identification and this technique can be used to
 identify both the recurrent laryngeal nerve (RLN) and the EBSLN. However, it remains unclear
 if there is any IONM added-value to the clinical outcome of thyroidectomy in terms of
 preserved individual voice performance. This study was designed to test that hypothesis.
Inclusion Criteria:

 -  thyroid pathology qualified for first-time bilateral neck surgery in a female patient
 with small to moderate sized goiter (below 100 ml in volume).

 Exclusion Criteria:

 -  male gender,

 -  previous neck surgery,

 -  unilateral thyroid pathology eligible for unilateral lobectomy,

 -  goiter volume above 100 ml,

 -  preoperatively diagnosed RLN palsy,

 -  abnormal preoperative voice assessment on GRBAS scale,

 -  pregnancy or lactation,

 -  age below 18 years,

 -  high-risk patients ASA 4 grade (American Society of Anesthesiology),

 -  inability to comply with the scheduled follow-up protocol.