Distinct Disease and Functional Characteristics of Thyroid Surgery-Related Vocal Fold Palsy

Improvement in swallowing safety after injection laryngoplasty in patients with unilateral vocal paralysis complicated with aspiration

BACKGROUND

The benefit of injection laryngoplasty (IL) on voice for unilateral vocal fold paralysis (UVFP) is supported increasingly in literatures, yet less is known for swallowing. Also, prevalence of patient-reported dysphagia is substantially higher than instrumental studies. This prospective study focused on swallowing outcomes, with predetermined flexible endoscopic evaluation of swallowing (FEES) protocol that simulates daily life situation.

METHODS

Adult patients with UVFP and aspiration receiving IL were recruited. Voice outcome measurements, as well as swallowing outcomes including Eating Assessment Tool (EAT-10) and FEES, which challenged patients with different fluid volumes: 10 mL, 20 mL, and 90 mL cup sipping were evaluated.

RESULTS

Significant improvements were demonstrated in all voice outcomes. Significant changes were also presented inEAT-10 (P < 0.01). Pre-operatively, penetration-aspiration scale (PAS) was 1.5 ± 1.3, 1.9 ± 1.7 and 2.3 ± 1.8 for 10 mL, 20 mL and 90 mL serial sipping, and improved to 1.1 ± 0.3, 1.1 ± 0.4 and 1.4 ± 0.7 post-operatively (P < 0.01). Safe swallowing (PAS ≤ 2) was achieved in all, except for one patient, who presented with a post-injection PAS of 4 (material enters the airway, contacts the vocal folds, and is ejected from the airway) on 90 mL cup sipping, whose pre-injection PAS was 7 (residue in trachea).

CONCLUSION

Maintaining swallowing function suitable for social environment is important. Our results demonstrated the feasibility of the predetermined FEES protocol, and positive effects of IL on both voice and swallowing outcomes.

Selective Electrical Surface Stimulation to Support Functional Recovery in the Early Phase After Unilateral Acute Facial Nerve or Vocal Fold Paralysis

This article addresses the potential clinical value of surface electrical stimulation in the acute phase of denervation after the onset of facial nerve or recurrent laryngeal nerve paralysis. These two nerve lesions are the most frequent head and neck nerve lesions. In this review, we will work out several similarities concerning the pathophysiology features and the clinical scenario between both nerve lesions, which allow to develop some general rules for surface electrical stimulation applicable for both nerve lesions. The focus is on electrical stimulation in the phase between denervation and reinnervation of the target muscles. The aim of electrostimulation in this phase of denervation is to bridge the time until reinnervation is complete and to maintain facial or laryngeal function. In this phase, electrostimulation has to stimulate directly the denervated muscles, i.e. muscle stimulation and not nerve stimulation. There is preliminary data that early electrostimulation might also improve the functional outcome. Because there are still caveats against the use of electrostimulation, the neurophysiology of denervated facial and laryngeal muscles in comparison to innervated muscles is explained in detail. This is necessary to understand why the negative results published in several studies that used stimulation parameters are not suitable for denervated muscle fibers. Juxtaposed are studies using parameters adapted for the stimulation of denervated facial or laryngeal muscles. These studies used standardized outcome measure and show that an effective and tolerable electrostimulation of facial and laryngeal muscles without side effects in the early phase after onset of the lesions is feasible, does not hinder nerve regeneration and might even be able to improve the functional outcome. This has now to be proven in larger controlled trials. In our view, surface electrical stimulation has an unexploited potential to enrich the early therapy concepts for patients with unilateral facial or vocal fold paralysis.

Artificial intelligence-augmented, label-free molecular imaging method for tissue identification, cancer diagnosis, and cancer margin detection

Label-free high-resolution molecular and cellular imaging strategies for intraoperative use are much needed, but not yet available. To fill this void, we developed an artificial intelligence-augmented molecular vibrational imaging method that integrates label-free and subcellular-resolution coherent anti-stokes Raman scattering (CARS) imaging with real-time quantitative image analysis via deep learning (artificial intelligence-augmented CARS or iCARS). The aim of this study was to evaluate the capability of the iCARS system to identify and differentiate the parathyroid gland and recurrent laryngeal nerve (RLN) from surrounding tissues and detect cancer margins. This goal was successfully met.

Two trajectories of functional recovery in thyroid surgery related unilateral vocal cord paralysis

BACKGROUND

Iatrogenic unilateral vocal fold paralysis caused by thyroid surgery induces profound physical and psychosocial distress in patients. The natural course of functional recovery over time differs substantially across subjects, but the mechanisms underlying this difference remain unclear. In this study, we examined whether the anatomic site of the lesion affected the trajectory of recovery.

METHODS

In this prospective case series study in a single medical center, patients with thyroid surgery-related unilateral vocal fold paralysis were evaluated using quantitative laryngeal electromyography, videolaryngostroboscopy, voice acoustic analysis, the Voice Outcome Survey, and the Short Form-36 quality-of-life questionnaire. Patients with and without superior laryngeal nerve injuries were compared.

RESULTS

Forty-two patients were recruited, among whom 15 and 27 were assigned to the with and without superior laryngeal nerve injury groups, respectively. Compared with the group without superior laryngeal nerve injury, the group with superior laryngeal nerve injury group demonstrated less improvement in the recruitment of vocal fold adductors, and the group also had more severe impairment of vocal fold vibration, maximum phonation time, jitter, shimmer, and harmony-to-noise ratio at the first evaluation. This difference was also found in the glottal gap and maximum phonation time 12 months after the injury.

CONCLUSION

Among patients with thyroid surgery-related unilateral vocal fold paralysis, superior laryngeal nerve injury induces a distinctively different recovery trajectory compared with those without superior laryngeal nerve injury characterized by less reinnervation of vocal fold adductors and worse presentation in terms of the glottal gap and maximum phonation time. This study emphasizes the importance of superior laryngeal nerve function and its preservation in thyroid surgery.

Clinical and functional characteristics of lung surgery-related vocal fold palsy

Background

Unilateral vocal fold paralysis (UVFP) caused by lung surgery is associated with prolonged hospital stay and increased postoperative comorbidities. We evaluated lung surgery-related UVFP and compared its characteristics with UVFP caused by esophageal and thyroid surgeries, as the most common surgical causes of UVFP. We also evaluated the outcomes of intracordal hyaluronate injection laryngoplasty in these patients.

Methods

Patients with surgery-related UVFP were evaluated by quantitative laryngeal electromyography, videolaryngostroboscopy, voice acoustic analysis, Voice Outcome Survey (VOS) questionnaire, and Short Form-36 Health Survey (SF-36) quality-of-life questionnaire. Data for the lung, esophageal, and thyroid surgery groups were compared and changes in outcome measurements induced by hyaluronate injection were compared among the three groups.

Results

A total of 141 patients were recruited, including 21, 46, and 74 in the lung, esophageal, and thyroid surgery groups, respectively. Compared with the other two groups, lung surgery patients had predominantly left-sided UVFP, less involvement of the external branch of the superior laryngeal nerve, and higher jitter. Most outcome measurements improved in all three groups after office-based hyaluronate injection, with the greatest improvement in jitter in the lung surgery group.

Conclusions

Lung surgery-related UVFP showed a distinct disease presentation, and patients' voice parameters and quality of life recovered dramatically after office-based hyaluronate injection. We recommend evaluation of lung surgery-related UVFP and early intervention, such as office-based hyaluronate injection, to improve patients' voice function and quality of life.

Risk factors for thyroid surgery-related unilateral vocal fold paralysis

Objectives/Hypothesis

We aimed to identify the risk factors for iatrogenic unilateral vocal fold paralysis (UVFP) caused by thyroid surgery, to allow the identification of patients requiring nerve‐protection procedures and monitoring technologies.

Study Design

Retrospective case study in a medical center.

Methods

Patients who underwent thyroid surgery from April 2011 to February 2016 and who were diagnosed with UVFP by laryngoscopy and laryngeal electromyography were included. Patient demographics, types of surgery, and characteristics of the thyroid lesions were analyzed.

Results

Sixty (2.1%) of 2,815 patients who received thyroid surgery developed UVFP. The risk of UVFP was higher in patients over 60 years old (odds ratio, 1.89; 95% confidence interval, 1.01‐3.26; P = .01). Involvement of the external branch of superior laryngeal nerve (EBSLN) occurred in 19 (31.7%) of the 60 UVFP patients, and was more likely to occurr in patients with diabetes mellitus (odds ratio, 14.19; 95% confidence interval, 3.80‐52.94; P < .001). The incidence of UVFP and involvement of the EBSLN differed among surgery types, and was the highest among patients undergoing total thyroidectomy with neck dissection (TTND) (10/158, 6.3% and 5/158, 3.2%, respectively).

Conclusions

The risk of thyroid surgery–related UVFP is higher in older patients. EBSLN involvement is more likely in patients with diabetes mellitus. TTND is associated with higher risks of UVFP and EBSLN injury than other types of surgery, implying the need of intraoperative nerve monitoring in these high‐risk characteristics.

Level of Evidence

4 Laryngoscope, 129:275–283, 2019

Implications of Synkinesis in Unilateral Vocal Fold Paralysis

Objectives

In patients with unilateral vocal fold paralysis (UVFP), laryngeal electromyography (LEMG) occasionally observes synkinesis in laryngeal muscles, a condition that could impair vocal fold mobility and voice control. This study aims to evaluate the impact of synkinesis on UVFP patients.

Study Design

A retrospective case-control study.

Setting

Medical center.

Subjects and Methods

Patients with UVFP onset >6 months were recruited (N = 104). The outcome measurements included LEMG, quantitative LEMG analysis of thyroarytenoid–lateral cricoarytenoid (TA-LCA) muscle complex, glottal gap measured by videolaryngostroboscopy, voice-related quality of life, and voice acoustic analysis.

Results

According to the LEMG analysis, 8 patients (8%) had synkinesis, and 96 (92%) did not. In the synkinesis group, TA-LCA turn frequency in the lesioned side was comparable to that in the healthy side ( P = .52). Patients in the synkinesis group had higher TA-LCA turn frequency ( P = .001), higher probability of cricothyroid muscle dysfunction ( P = .04), and better voice-related quality of life ( P = .01) but objective voice outcomes comparable to those in the nonsynkinesis group.

Conclusions

Patients with synkinesis will have near-complete restoration in TA-LCA turn frequency but still experience voice impairment, a finding that is compatible with the mechanism of aberrant reinnervation. However, patients with synkinesis have better disease-related quality of life than do those without synkinesis.