Diagnosis and management of unilateral thyroarytenoid muscle palsy

Abstract

The objective of this study is to assess and propose a method of diagnosis and management of patients with unilateral thyroarytenoid muscle palsy (TAMP). This is a retrospective review of clinical records. The records of seven patients diagnosed as having idiopathic TAMP were reviewed. Despite the adductive and abductive functions of the vocal folds being within normal range, apparent palsy was seen in the unilateral thyroarytenoid muscle of these patients. TAMP was confirmed by laryngeal electromyography, and the adductive and abductive movements of the vocal folds were evaluated as the mobility of the arytenoid cartilages by three-dimensional computed tomography and endoscopy. Most of patients with TAMP had been diagnosed as having other diseases or normal, and in one patient, it took over 6 years to establish a correct diagnosis. Two patients recovered by conservative treatment; however, in five patients, TAMP remained even after 6 months. In 4 of those 5 patients, treatment with hyaluronic acid injections was performed. In the remaining patient, surgical treatment, namely, nerve-muscle pedicle flap implantation was performed, which resulted in a favorable recovery of phonation. The average maximum phonation time (MPT) of all patients was extended from 11.4 (±4.4) s before treatment to 19.9 (±4.3) s after treatment, and the pitch range was also increased from 25.1 (±7.2) to 34.6 (±5.8) semitones following our management course. Our results indicate that there is a possibility that TAMP can be diagnosed and treated sufficiently. Therefore, further research toward establishing the concept of and treatment for TAMP is anticipated.

Isolated Paresis of Laryngeal Adduction: What Are the Laryngoscopic and Stroboscopic Findings?

“…Paresis of the vocal fold is a poorly understood clinical entity . It may result from incomplete paralysis of the vagus, superior, and inferior laryngeal nerves, or paralysis of terminal branches to specific ILMs . Findings on VLS depend on the degree of neurological impairment, the affected muscle or muscles, and the relative compensation from the unaffected muscles .…”

“…Therefore, VLS findings are not specific and may include asymmetries in gross motion, glottal configuration, and mucosal wave formation during phonation . Furthermore, the distinction among neurological impairment, functional or behavioral disorder, and innocent laryngeal asymmetry on VLS is not straightforward …”

“…Most of the correlated literature concerns paralysis of the external branch of the superior laryngeal nerve, affecting the ipsilateral cricothyroid (CT) muscle . Descriptions of selective paralysis of ILMs innervated by the inferior laryngeal nerve are much scarcer …”

“…If both muscles are paralyzed, a condition referred to as vocal fold adductor paralysis develops, leading to impairment of vocal fold adduction, with preserved abduction . However, if the neurological compromise is restricted to the TA muscle or there is limited impairment of other adductors (LCA and arytenoid muscles), the mobility of the glottis may be preserved, whereas vocal fold vibration may be disturbed . This condition, referred as isolated paresis of laryngeal adduction, leads to vocal insufficiency and dysphonia that may be difficult to diagnose.…”

“…Laryngeal electromyography (LEMG) becomes an essential tool in the diagnosis of such patients, but a high index of suspicion is necessary to warrant its correct indication. Unfortunately, findings on VLS in these patients are not described in detail.…”