A long-term comparative prospective study between reinnervation and injection laryngoplasty

Proposal of integrated clinical pathway in the management of perioperative recurrent laryngeal nerve injury post thyroid and parathyroid surgery

Early intervention is the current paradigm shift in the management of recurrent laryngeal nerve (RLN) injury post thyroidectomy and parathyroidectomy. Thus, an integrated clinical pathway is needed to enable early detection of RLN injury. A prospective longitudinal study was conducted from 2015 until 2021 in a single tertiary centre. A clinical pathway was developed where routine perioperative laryngeal assessments were implemented for all patients who underwent thyroidectomy and parathyroidectomy. Following an RLN injury, early surgical intervention was performed for unilateral vocal fold paralysis (UVFP). Data on patient demographics, risk factors, timing of RLN injury detection and type of intervention received were recorded in a proforma and analysed. 397 patients were included, involving 660 nerves at risk. The incidences of permanent RLN injury following thyroidectomy and parathyroidectomy were 5% and 1.8% respectively. The usage of intraoperative neuromonitoring was the only significant factor that affected the RLN injury according to multivariate analysis. 15% of RLN injuries were detected intraoperatively and 98% within two days. 70% of patients with UVFP received intervention in less than two weeks. The integrated clinical pathway has improved the validity of RLN injury incidence. It allows early detection of RLN injury and facilitates immediate intervention.

A Novel Option for Revision Medialization: Repeat Reinnervation

Nonselective laryngeal reinnervation (NSLR) shows comparable voice results to thyroplasty after one year without permanent implants. In the rare case of a second ipsilateral vocal fold paralysis after NSLR, we present the first recorded revision NSLR. Case report. A 51 year old woman with a history of right NSLR in 2017 for vocal fold paralysis after an anterior cervical diskectomy and fusion (ACDF) presented for re-evaluation prior to a revision of her ACDF. Ipsilateral revision was recommended to reduce the risk of bilateral vocal fold paralysis. Post-operatively, she was noted to have vocal fold immobility. Her maximum phonation time at that time was 9 s. Her voice was moderately breathy and moderately asthenic. Fundamental frequency (F0) was 211 Hz. Jitter was 2.868%, and shimmer 14.429%. Noise to harmonic ratio was 0.366. Cepstral peak prominence was 2.689. After being offered thyroplasty or revision reinnervation, she opted for revision reinnervation due to a strong preference for her reinnervated voice. She underwent a revision cross-neck NSLR with a commercial nerve graft in September 2022. One year later, her MPT was found to be 7.6 s, with mild breathiness and asthenia. F0 was 190 Hz. Jitter decreased to 2.42%, shimmer to 6.478%, and NHR to 0.165. Cepstral peak prominence increased to 4.427. VHI decreased from 35 pre-operatively to 7 post-operatively. We present the first case of a revision NSLR. Notable improvement has been found in objective voice measures and patient-reported outcomes post-operatively, demonstrating feasibility in similar patients. Laryngoscope, 135:239-240, 2025.

Timing of Ansa Cervicalis-to-recurrent Laryngeal Nerve Reinnervation: A Systematic Review

BACKGROUND

Ansa cervicalis-to-recurrent laryngeal nerve anastomosis (ARA) is an established technique for the treatment of recurrent laryngeal nerve (RLN) injury after head and neck surgery. However, the optimal timing of ARA remains unclear, and the evidence bases for ARA performed at each timepoint after RLN injury have not previously been clearly distinguished. We conducted a systematic review of the literature to evaluate the efficacy of ARA performed at different timepoints on postoperative voice outcomes.

METHODS

A review of English-language journal articles published in the last 20 years was undertaken on three electronic databases: Ovid MEDLINE, PubMed and Embase. Studies with a focus on paediatric RLN injury, bilateral RLN injury, ansa cervicalis anatomy and non-ARA techniques alone were excluded.

RESULTS

Twenty eight articles were included in the review. ARA was performed as a delayed surgery in 16/28 studies (57%), while immediate ARA was utilized in 14/28 studies (50%). On qualitative synthesis, delayed ARA was shown to be effective in improving patient-reported, subjective observer-reported and objective observer-reported voice outcomes. Likewise, a substantial body of evidence was identified demonstrating postoperative voice improvement with immediate ARA. On direct comparison of timepoints, some benefit was shown for early delayed ARA relative to late delayed operations, while no comparative data for immediate versus delayed repair were available in the literature.

CONCLUSIONS

ARA at both delayed and immediate timepoints is effective in the treatment of patients with RLN injury after head and neck surgery. The timing of ARA may have some influence on its efficacy, with early delayed repair potentially associated with superior outcomes to late delayed operations, and immediate ARA offering several practical advantages relative to delayed repair. Further comparative studies are required to better characterize the optimal timing of ARA after RLN injury.

Ten-year outcomes of recurrent laryngeal nerve reinnervation for thyroidectomy-related unilateral vocal fold paralysis: A single-surgeon, prospective study

OBJECTIVES

This study evaluated the long-term outcomes of intraoperative recurrent laryngeal nerve (RLN) reinnervation for managing thyroidectomy-related unilateral vocal fold paralysis (UVFP) over a period of 10 years and assessed the long-term efficacy of this technique.

METHODS

This study was conducted between March 2006 and July 2022 at Soonchunhyang University Bucheon Hospital. We enrolled 25 patients who underwent RLN reinnervation via direct neurorrhaphy or ansa cervicalis-to-RLN anastomosis and completed subjective and objective voice measurements over 5 years period. Among these, 10 patients completed voice measurements over 10 years period.

RESULTS

Six months post-RLN reinnervation, most subjective voice parameters and some of objective voice parameters showed significant improvement (p < 0.05). Twelve months after the procedure, most parameters demonstrated significant voice improvements. These improvements remained stable in follow-up examinations 10 years post-RLN reinnervation (p < 0.05).

CONCLUSIONS

With stable voice outcomes over a decade, primary intraoperative RLN reinnervation provides satisfactory voice outcomes for 10 years postoperatively. Concerning the long-term survival of thyroid cancer patients, primary intraoperative RLN reinnervation is the first recommended voice rehabilitation technique for thyroidectomy related permanent UVFP.

Effect of Aging on Vocal Outcomes After Laryngeal Reinnervation Combined With Arytenoid Adduction

OBJECTIVE

To evaluate the impact of aging on vocal function following laryngeal reinnervation combined with arytenoid adduction (AA) in the treatment of paralytic dysphonia.

METHODS

Sixty-eight patients with unilateral vocal fold paralysis who underwent refined nerve-muscle pedicle flap (NMP) implantation and AA were classified into four groups according to age: under 50 years (-50), in their 50s, 60s, and 70 years and older (70+). These groups consisted of 15, 14, 22, and 17 patients, respectively. Their vocal function was followed periodically for 24 months after surgery.

RESULTS

Vocal function in all groups showed significant improvement after surgery. Significant improvements in vocal function were observed during a 24-month follow-up period: maximum phonation time in the -50 and 50 seconds groups; pitch range and voice handicap index-10 in the -50, 50s, and 60s groups; "Grade" in the -50, 50s, and 70+ groups; and "Breathiness" and voice-related quality of life in all groups. There were no significant differences in vocal function among the four groups, except for pitch range, at the 24-month postoperative assessment.

CONCLUSIONS

Although the younger groups tended to exhibit better vocal function compared to the older groups 24 months postoperatively, the refined NMP+AA proved effective in the treatment of breathy dysphonia resulting from unilateral vocal fold paralysis, not only in the younger population but also in the older population.

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.

The Role of Primary Repair of the Recurrent Laryngeal Nerve during Thyroid/Parathyroid Surgery in Vocal Outcomes-A Systematic Review

Recurrent laryngeal nerve (RLN) injury is a well and long-known complication of thyroid and parathyroid surgery that significantly affects the quality of life of patients. Despite the advances in surgical techniques and technology, it still occurs in clinical practice either as temporary paresis or as permanent paralysis of the corresponding vocal cord. The purpose of the current systematic review is to examine the value of intraoperative repair of the RLN in voice restoration. A systematic review of the existing literature was conducted using PubMed, Scopus, Cochrane Library, and Google Scholar databases according to the PRISMA guidelines. The systematic review resulted in 18 studies, which met the inclusion criteria. An improvement in phonatory function and voice quality was observed in all these studies after immediate RLN reconstruction (not always statistically significant). This improvement appears to be comparable to or even higher than that achieved with other methods of repair, and in some cases, the improvement approaches levels found in normal subjects. Intraoperative RLN reconstruction is not widely used in clinical practice, but the evidence so far makes it a viable and safe alternative to traditional techniques with better long-term results, as it prevents the occurrence of atrophy of the vocal cord and should be considered in the operating room if possible.

Tissue Engineering as a Promising Treatment for Glottic Insufficiency: A Review on Biomolecules and Cell-Laden Hydrogel

Glottic insufficiency is widespread in the elderly population and occurs as a result of secondary damage or systemic disease. Tissue engineering is a viable treatment for glottic insufficiency since it aims to restore damaged nerve tissue and revitalize aging muscle. After injection into the biological system, injectable biomaterial delivers cost- and time-effectiveness while acting as a protective shield for cells and biomolecules. This article focuses on injectable biomaterials that transport cells and biomolecules in regenerated tissue, particularly adipose, muscle, and nerve tissue. We propose Wharton's Jelly mesenchymal stem cells (WJMSCs), induced pluripotent stem cells (IP-SCs), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), insulin growth factor-1 (IGF-1) and extracellular vesicle (EV) as potential cells and macromolecules to be included into biomaterials, with some particular testing to support them as a promising translational medicine for vocal fold regeneration.

Care and Management of Voice Change in Thyroid Surgery: Korean Society of Laryngology, Phoniatrics and Logopedics Clinical Practice Guideline

Voice change is a common complaint after thyroid surgery and has a significant impact on quality of life. The Korean Society of Laryngology, Phoniatrics and Logopedics assembled a task force to establish guideline recommendations on education, care, and management related to thyroid surgery. The guideline recommendations encompass preoperative voice education, management of anticipated voice change during surgery, and comprehensive voice care after thyroid surgery, and include in-depth information and up-to-date knowledge based on validated literature. The committee constructed 14 key questions (KQs) in three categories-preoperative (KQ 1-2), intraoperative (KQ 3-8), and postoperative (KQ 9-14) management-and developed 18 evidence-based recommendations. The Delphi survey reached an agreement on each recommendation. A detailed evidence profile is presented for each recommendation. The level of evidence for each recommendation was classified as high-quality, moderate-quality, or low-quality. The strength of each recommendation was designated as strong or weak considering the level of evidence supporting the recommendation. The guidelines are primarily targeted toward physicians who treat thyroid surgery patients and speech-language pathologists participating in patient care. These guidelines will also help primary care physicians, nurses, healthcare policymakers, and patients improve their understanding of voice changes and voice care after thyroid surgery.

Prognostic Indicators of Non-Transection Nerve Injury and Vocal Fold Motion Impairment After Thyroid Surgery - Correlation Between Intraoperative Neuromonitoring Findings and Perioperative Voice Parameters

OBJECTIVES

In patients with recurrent laryngeal nerve (RLN) injury after thyroid surgery, unrecovered vocal fold motion (VFM) and subjective voice impairment cause extreme distress. For surgeons, treating these poor outcomes is extremely challenging. To enable early treatment of VFM impairment, this study evaluated prognostic indicators of non-transection RLN injury and VFM impairment after thyroid surgery and evaluated correlations between intraoperative neuromonitoring (IONM) findings and perioperative voice parameters.

METHODS

82 adult patients had postoperative VFM impairment after thyroidectomy were enrolled. Demographic characteristics, RLN electromyography (EMG), and RLN injury mechanism were compared. Multi-dimensional voice program, voice range profile and Index of voice and swallowing handicap of thyroidectomy (IVST) were administered during I-preoperative; II-immediate, III-short-term and IV-long-term postoperative periods. The patients were divided into R/U Group according to the VFM was recovered/unrecovered 3 months after surgery. The patients in U Group were divided into U1/U2 Group according to total IVST score change was <4 and ≥4 during period-IV.

RESULTS

Compared to R Group (42 patients), U Group (38 patients) had significantly more patients with EMG >90% decrease in the injured RLN (p<0.001) and thermal injury as the RLN injury mechanism (p=0.002). Voice parameter impairments were more severe in U Group compared to R Group. Compared to U1 group (19 patients), U2 Group (19 patients) had a significantly larger proportion of patients with EMG decrease >90% in the injured RLN (p=0.022) and thermal injury as the RLN injury mechanism (p=0.017). A large pitch range decrease in period-II was a prognostic indicator of a moderate/severe long-term postoperative subjective voice impairment.

CONCLUSION

This study is the first to evaluate correlations between IONM findings and voice outcomes in patients with VFM impairment after thyroid surgery. Thyroid surgeons should make every effort to avoid severe type RLN injury (e.g., thermal injury or injury causing EMG decrease >90%), which raises the risk of unrecovered VFM and moderate/severe long-term postoperative subjective voice impairment. Using objective voice parameters (e.g., pitch range) as prognostic indicators not only enables surgeons to earlier identify patients with low voice satisfaction after surgery, and also enable implementation of interventions sufficiently early to maintain quality of life.

Guidelines for the Management of Unilateral Vocal Fold Paralysis From the Korean Society of Laryngology, Phoniatrics and Logopedics

The Korean Society of Laryngology, Phoniatrics and Logopedics appointed a task force to establish clinical practice guidelines for the management of unilateral vocal fold paralysis (UVFP). These guidelines cover a comprehensive range of management-related factors, including the diagnosis and treatment of UVFP, and provide in-depth information based on current, up-to-date knowledge. Detailed evidence profiles are provided for each recommendation. The CORE databases, including OVID Medline, Embase, the Cochrane Library, and KoreaMed, were searched to identify all relevant papers, using a predefined search strategy. When insufficient evidence existed, expert opinions and Delphi questionnaires were used to fill the evidence gap. The committee developed 16 evidence-based recommendations in six categories: initial evaluation (R1–4), spontaneous recovery (R5), medical treatment (R6), surgical treatment (R7–14), voice therapy (R15), and aspiration prevention (R16). The goal of these guidelines is to assist general otolaryngologists and speech-language pathologists who are primarily responsible for treating patients with UVFP. These guidelines are also intended to facilitate understanding of the condition among other health-care providers, including primary care physicians, nurses, and policy-makers.

Does Dysphagia Improve Following Laryngeal Reinnervation for Treatment of Hoarseness in Unilateral Vocal Fold Paralysis?

PURPOSE

There are many reports of the efficacy of laryngeal reinnervation on voice, but there is a paucity of literature regarding its impact on swallowing function. The goal of this study was to explore the impact of laryngeal reinnervation on swallowing outcomes among unilateral vocal fold paralysis (UVFP) patients.

METHODS

We reviewed 22 UVFP cases treated with laryngeal reinnervation at our institution. Ten patients had complete datasets, including Eating Assessment Tool (EAT-10) scores and appropriate follow-up. Wilcoxon signed-rank test was used to compare pre- and postoperative scores.

RESULTS

Over the study period, 10 cases (mean age 45.7 ± 13.3 years; 6/10 men) with UVFP underwent ansa cervicalis to recurrent laryngeal nerve anastomosis (6/10) or nerve-muscle pedicle procedure (4/10). The median time between injury and surgical reinnervation was 12.4 months (range 2.7-88.5 months). Based on EAT-10 scores 6/10 patients were found to have dysphagia. Of these, four improved their score after surgery, one remained stable, and one deteriorated. The median EAT-10 score of these patients improved from 13 to 7 after surgery, but this difference was not statistically significant (P = 0.138).

CONCLUSION

Laryngeal reinnervation procedure has the potential for restoring a near normal voice in UVFP. Laryngeal reinnervation of the vocal fold may be associated with a tendency toward improvement in the EAT-10 score in patients after surgery for hoarseness in the setting of UVFP.

Stroboscopic assessment of unilateral vocal fold paralysis: a systematic review

PURPOSE

To review the relevant basic stroboscopic evaluations in unilateral vocal fold paralysis (UVFP). Our aim was twofold: (1) to determine the frequency of use of stroboscopic parameters in outcome evaluation after surgical treatment of UVFP using a Pareto diagram; and (2) to select the most relevant parameters in terms of a significant difference between pre- and post-surgical intervention for UVFP.

METHODS

A systematic review in PUBMED includes studies on stroboscopic evaluation in combination with UVFP and surgical treatment. The review was limited to English studies published between 1990 and March 2018. The most frequently used stroboscopic parameters were identified using a Pareto diagram. Then, 'the percentage of significance' for the most frequently stroboscopic parameters was identified by comparing the number of studies that showed a statistically significant change in pre- and post-treatment results with the total number of studies using the same parameters.

RESULTS

Seven stroboscopic parameters were nominated using the Pareto diagram. In decreasing order of citation frequency, periodicity, edge bowing, mucosal wave, glottic gap, position of vocal fold, amplitude, and symmetry have respective percentages of significance of 87.5%, 83.3%, 77.7%, 64.5%, 60%, 57.1%, and 50%. Five pertinent scales were selected for the most frequent and significant stroboscopic parameters.

CONCLUSIONS

The results indicate that periodicity, edge bowing, mucosal wave, glottic gap, and position of vocal fold represent the five most frequently used and relevant stroboscopic parameters in UVFP evaluation. The current review outlines a proposal scale of these stroboscopic parameters.

PROSPERO REGISTRATION NUMBER

CRD42019126786.