Approach to diagnosis of vocal fold immobility: a literature review

Primary Nonselective Laryngeal Reinnervation in Iatrogenic Acute Recurrent Laryngeal Nerve Injury: Case Series and Literature Review

Treating an acutely injured recurrent laryngeal nerve by primary nonselective laryngeal reinnervation (LR) during thyroidectomy is encouraged to minimize postoperative morbidity. Performing a concurrent transoral temporary injection laryngoplasty (IL) may improve the patient's voice while waiting for the effect of successful reinnervation. Chronological multidimensional voice outcomes (qualitative and quantitative) and combination of the primary nonselective LR with concurrent transoral IL were not explicitly demonstrated in previous cases that published the literature. In this study, the authors presented the multidimensional voice parameters of 3 patients undergoing primary nonselective LR with concurrent IL during thyroidectomy. The parameters were measured at different time points (2 weeks and 1, 3, 6, and 12 months) following the surgery. Laryngeal electromyography was done at 1 to 2 months and 12 months postsurgery. The results showed that the voices, qualitatively and quantitatively, were within normal range at within 3 months postintervention. The parameters were slightly beyond the normal limit at 3 months and returned to normal at 6 months postintervention and beyond. The LEMG depicted evidence of successful reinnervation in which the motor unit was normal comparable to the opposite normal vocal fold.

Ultrasonography diagnostic validity in structural and functional laryngeal disorders

Background

The diagnostic approach for patients with laryngeal lesions differs among otolaryngologists. Indirect laryngoscopy, flexible fibrooptic laryngoscopy, CT, and MRI are all modalities used for diagnosis. Ultrasonography is noninvasive, non-irradiating, and safe. The availability, affordability, and usability of portable ultrasound units have undergone dramatic improvements. It is well tolerated by patients, dynamic technique that can be performed easily in phonation, quickly performed, and allows for photo-documentation. Our objective is to evaluate the laryngeal ultrasound as a diagnostic tool to evaluate different laryngeal structure as regard laryngeal dynamics (range and abnormality), and anatomic structures. This prospective study was carried out on individuals in “blinded for peer review” hospitals. They were divided into group I (healthy volunteers), group II (unilateral vocal fold paralysis), and group III (patients underwent vertical hemilaryngectomies). All patients were subjected to full history taking, detailed head and neck examination, and fibrooptic nasopharyngolaryngoscopy then all patients underwent laryngeal sonographic examination. The photos were analyzed to identify various laryngeal structures and to measure glottic areas and inter-arytenoid distances.

Results

After recognition of laryngeal anatomic details and different measurements, we found that the percent of change in length and area were much less in group III than group I or II. Another important finding is that glottic area during respiration is related significantly to interarytenoid length during respiration with a statistically significant regression coefficient.

Conclusion

Laryngeal ultrasound is a valid diagnostic tool for imaging laryngeal structures and measuring various distances and areas inside the larynx. It is recommended to consider ultrasonography as a reliable imaging modality, and at least a useful adjunct to endoscopy when identification of airway patency, vocal fold mobility, or structural alterations is suspected. To our best knowledge, this study may contain a hitherto undescribed correlation between inter-arytenoid length and glottic area.

Functional analysis of vocal folds by transcutaneous laryngeal ultrasonography in patients undergoing thyroidectomy

BACKGROUND

Transcutaneous laryngeal ultrasound (TCLUS) can assess Vocal folds (VF) by subjectively identifying mobility or objectively by calculating vocal fold displacement velocity (VFDV). Optimal diagnostic approach (subjective assessment, VFDV estimation or a combination of both) is unresolved; hence, we conducted this prospective study in patients undergoing thyroidectomy.

METHOD

Two anaesthetists performed TCLUS pre- and post-operatively for functional assessment of 200 VFs on 100 patients. Their findings were compared with pre-operative flexible laryngoscope (FL) performed by surgeons and with post-operative C-Mac video laryngoscope (C-Mac VL) by another independent anaesthetist. Correlation between FL and TCLUS findings and inter-rater agreement between TCLUS findings of both anaesthetists was analysed. Decision curve analysis (DCA) was performed to compare clinical benefit of hoarseness, subjective VF movement, VFDV, and combined assessment for detecting disabled VFs.

RESULTS

We found good correlation between VF mobility on TCLUS and FL (Spearman's r = 0.93, P < 0.0001) as well as C-Mac VL (Spearman's r = 0.83, P < 0.0001) with excellent inter-rater agreement between both anaesthetists. DCA showed combined assessment to have marginally higher clinical benefit than other diagnostic approaches at intermediate threshold probabilities while its benefit was similar to subjective evaluation at higher threshold probabilities.

CONCLUSION

Provided achievement of optimal acoustic window, TCLUS can reliably assess disabled VFs with FL reserved for their confirmation or doubtful cases. Subjective assessment of VF mobility should suffice in most cases with additional VFDV estimation reserved pre-operatively for situations with higher risk of VFs disability, and post-operatively when subjective VF assessment findings are discordant from pre-operative status.