Intra-operative nerve monitoring and recurrent laryngeal nerve injury during thyroid surgery: a network meta-analysis of prospective studies.

PURPOSE: Recurrent laryngeal nerve (RLN) injury is a feared complication of thyroid surgery occurring in 1-5% of cases. The present approaches to RLN preservation include RLN visualization with no nerve monitoring (No-NM), intermittent intra-operative nerve monitoring (I-IONM) and continuous intra-operative nerve monitoring (C-IONM). There is ambiguity as to which of these strategies should be the preferred method of RLN preservation. METHODS: A systematic review of the PubMed, Embase and the Cochrane Collaboration databases was undertaken with network meta-analysis (NMA) performed according to the PRISMA and Cochrane Collaboration guidelines. A Bayesian NMA was conducted using R packages netmeta with outcomes expressed as odds ratios (ORs) with 95% credible intervals (CrI). Only prospective studies were included. RESULTS: Eighteen studies met inclusion criteria, including 22,080 patients and 40,642 nerves at risk (NAR). Overall, 23,364 NARs (57.5%) underwent I-IONM, 17,176 (42.3%) No-NM and 98 (0.2%) underwent C-IONM. There were no significant differences between groups regarding the incidence of permanent RLN injury following thyroid surgery (I-IONM vs.No-NM, OR 0.84, 95% CrI 0.55-1.19; C-IONM vs. No-NM, OR 0.44, 95% CrI 0.02-5.00). Pooled analysis showed that IONM (I-IONM or C-IONM) demonstrated a protective effect versus No-NM in reducing the incidence of transient RLN injury (OR 0.75, 95% CI 0.59-0.97, p = 0.03). CONCLUSIONS: IONM strategies did not significantly reduce the incidence of permanent RLN injury following thyroid surgery. However, the small number of C-IONM NARs limits conclusions that may be drawn. Further well-designed prospective studies will be required to definitively assess the utility of C-IONM.

Surgical Significance of Berry's Posterolateral Ligament and Frequency of Recurrent Laryngeal Nerve Injury into the Last 2 cm of Its Caudal Extralaryngeal Part(P1) during Thyroidectomy.

Background and Objectives: Recurrent laryngeal nerve injury is one of the major complications of thyroidectomy, with the lateral thyroid ligament (Berry's ligament) being the most frequent site of nerve injury. Neuromonitoring during thyroidectomy revealed three possible anatomical regions of the recurrent laryngeal nerve P1, P2, and P3. P1 represents the recurrent laryngeal nerve's caudal extralaryngeal part and is primarily associated with Berry's ligament. The aim of this systematic review is to identify the anatomical region with the highest risk of injury of the recurrent laryngeal nerve (detected via neuromonitoring) during thyroidectomy and to demonstrate the significance of Berry's ligament as an anatomical structure for the perioperative recognition and protection of the nerve. Materials and Methods: This study conducts a systematic review of the literature and adheres to all PRISMA system criteria as well as recommendations for systematic anatomical reviews. Three search engines (PubMed, Scopus, Cochrane) were used, and 18 out of 464 studies from 2003-2018 were finally included in this meta-analysis. All statistical data analyses were performed via SPSS 25 and Microsoft Office XL software. Results: 9191 nerves at risk were identified. In 75% of cases, the recurrent laryngeal nerve is located superficially to the ligament. In 71% of reported cases, the injury occurred in the P1 area, while the P3 zone (below the location where the nerve crosses the inferior thyroid artery) had the lowest risk of injury. Data from P1, P2, and P3 do not present significant heterogeneity. Conclusions: Berry's ligament constitutes a reliable anatomical structure for recognizing and preserving recurrent laryngeal nerves. P1 is the anatomical area with the greatest risk of recurrent laryngeal nerve damage during thyroidectomy, compared to P2 and P3.

Precision treatment of post pneumonectomy unilateral laryngeal paralysis due to cancer.

Aim: The aim of this study is to assess the efficacy of external laryngeal medialization acquired through a Gore-Tex implant in a 45 patients affected by unilateral vocal fold paralysis in abduction after pneumonectomy. Method: The cohort of patients was made up of 30 male (73.1%) and 11 female patients (26.9%) with an average age of 66.7 years in a range between 46 and 78 years. Results: The results were analyzed with the objective and subjective analysis of voicing and swallowing. In 95.2% of cases, voice and swallow improvement with statistically significant evidences. Conclusion: We can conclude that Gore-Tex implantation is a simple, reproducible and minimally invasive procedure for management of selected cases of vocal fold unilateral paralysis in the abductory position.

Selective vagus-recurrent laryngeal nerve anastomosis in thyroidectomy with cancer invasion or iatrogenic transection.

PURPOSE: Immediate recurrent laryngeal nerve (RLN) reconstruction at the time of thyroid cancer extirpation can provide excellent postoperative phonatory function. This study is to present our experience with the methods of RLN reconstruction, and to evaluate the role of selective vagus to RLN anastomosis (SVR) in thyroidectomy. METHODS: Respective review of RLN reconstruction in thyroid surgery from January 2004 to October 2018 was conducted in two tertiary referral academic medical centers. Immediate RLN reconstruction was performed for primary thyroidectomy patients with intraoperative nerve tumor invasion or iatrogenic transection. Laryngofiberoscopic examination, voice evaluation of maximum phonation time, and GRBAS scale were performed preoperatively, on the second day after surgery, and monthly postoperatively for the first year. RESULTS: A total of 37 patients were enrolled. Twenty-nine RLNs were resected caused by tumor-associated trauma; the other nerves were inadvertently transected. Direct anastomosis (DA) was performed in eight patients, free nerve graft (FNG) was performed in four patients, ansa cervicalis to RLN anastomosis (ARA) was performed in eight patients, and SVR was performed in 17 patients. The mean periods from the reinnervation surgery of DA, SVR, ARA, and FNG to the phonation recovery were 46 ± 19 (days), 41 ± 29 (days), 83 ± 21 (days), and 137 ± 32 (days), respectively. There were improvements in the GRBAS scale of perceptual voice quality at 1 month for DA and SVR, 2months for ARA. CONCLUSIONS: Intraoperative SVR reinnervation demonstrated voice improvement postoperatively and might be an effective treatment for thyroidectomy-related permanent unilateral vocal cord paralysis.

A Surgical Mouse Model for Advancing Laryngeal Nerve Regeneration Strategies.

Iatrogenic recurrent laryngeal nerve (RLN) injury is a morbid complication of anterior neck surgical procedures. Existing treatments are predominantly symptomatic, ranging from behavioral therapy to a variety of surgical approaches. Though laryngeal reinnervation strategies often provide muscle tone to the paralyzed vocal fold (VF), which may improve outcomes, there is no clinical intervention that reliably restores true physiologic VF movement. Moreover, existing interventions neglect the full cascade of molecular events that affect the entire neuromuscular pathway after RLN injury, including the intrinsic laryngeal muscles, synaptic connections within the central nervous system, and laryngeal nerve anastomoses. Systematic investigations of this pathway are essential to develop better RLN regenerative strategies. Our aim was to develop a translational mouse model for this purpose, which will permit longitudinal investigations of the pathophysiology of iatrogenic RLN injury and potential therapeutic interventions. C57BL/6J mice were divided into four surgical transection groups (unilateral RLN, n = 10; bilateral RLN, n = 2; unilateral SLN, n = 10; bilateral SLN, n = 10) and a sham surgical group (n = 10). Miniaturized transoral laryngoscopy was used to assess VF mobility over time, and swallowing was assessed using serial videofluoroscopy. Histological assays were conducted 3 months post-surgery for anatomical investigation of the larynx and laryngeal nerves. Eight additional mice underwent unilateral RLN crush injury, half of which received intraoperative vagal nerve stimulation (iVNS). These 8 mice underwent weekly transoral laryngoscopy to investigate VF recovery patterns. Unilateral RLN injury resulted in chronic VF immobility but only acute dysphagia. Bilateral RLN injury caused intraoperative asphyxiation and death. VF mobility was unaffected by SLN transection (unilateral or bilateral), and dysphagia (transient) was evident only after bilateral SLN transection. The sham surgery group retained normal VF mobility and swallow function. Mice that underwent RLN crush injury and iVNS treatment demonstrated accelerated and improved VF recovery. We successfully developed a mouse model of iatrogenic RLN injury with impaired VF mobility and swallowing function that can serve as a clinically relevant platform to develop translational neuroregenerative strategies for RLN injury.

Selective laryngeal reinnervation: can rerouting of the thyrohyoid nerve simplify the procedure by avoiding the use of a nerve graft?

PURPOSE: The objective of this study was to record the descriptive and metric anatomical characteristics of the thyrohyoid nerve with the aim of rerouting it in a selective laryngeal reinnervation procedure. METHODS: An anatomical study was performed on ten formalin-embalmed cadavers. The origin of the thyrohyoid nerve and the superior root of the ansa cervicalis, the location of the thyrohyoid nerve ending in the thyrohyoid muscle, and the recurrent laryngeal nerve were established. Then, a rerouting of the thyrohyoid nerve was performed. We measured the length of thyrohyoid nerve, the distance between the thyrohyoid nerve ending and the recurrent laryngeal nerve at the horizontal level of the cricothyroid joint before and after the rerouting, and the distance between the origin of the thyrohyoid nerve and the superior root of the ansa cervicalis. RESULTS: The thyrohyoid nerve was identified on both sides in all the cases. The average length of the thyrohyoid nerve was 27 mm. The end of the thyrohyoid nerve was found in 100% of the cases at the upper outer quarter of the thyrohyoid muscle. After the rerouting, an average reduction of 30% of the distance between the end of the thyroid nerve and the recurrent laryngeal nerve at the horizontal level of the cricothyroid joint was measured. CONCLUSION: The rerouting of the thyrohyoid nerve provided a reduction in the length of the nerve graft in laryngeal reinnervation. Moreover, the constancy of the thyrohyoid nerve and its characteristics make it a valuable anatomical base for laryngeal reinnervation and laryngeal innervated allotransplantation.

Recovery of Voice After Reconstruction of the Recurrent Laryngeal Nerve and Adjuvant Nimodipine.

BACKGROUND: Transection injury to the recurrent laryngeal nerve (RLN) has been associated with permanent vocal fold palsy, and treatment has been limited to voice therapy or local treatment of vocal folds. Microsurgical repair has been reported to induce a better function. The calcium channel antagonist nimodipine improves functional recovery after experimental nerve injury and also after cranial nerve injury in patients. This study aims to present voice outcome in patients who underwent repair of the RLN and received nimodipine during regeneration. METHODS: From 2002-2016, 19 patients were admitted to our center with complete unilateral injury to the RLN and underwent microsurgical repair of the RLN. After nerve repair, patients received nimodipine for 2-3 months. Laryngoscopy was performed repeatedly up to 14 months postoperatively. The Voice Handicap Index (VHI) was administered, and patients' maximum phonation time (MPT) was recorded during the follow-up. RESULTS: All patients recovered well after surgery, and nimodipine was well tolerated with no dropouts. None of the patients suffered from atrophy of the vocal fold, and some patients even showed a small ab/adduction of the vocal fold on the repaired side with laryngoscopy. During long-term follow-up (>3 years), VHI and MPT normalized, indicating a nearly complete recovery from unilateral RLN injury. CONCLUSIONS: In this cohort study, we report the results of the first 19 consecutive cases at our center subjected to reconstruction of the RLN and adjuvant nimodipine treatment. The outcome of the current strategy is encouraging and should be considered after iatrogenic RLN transection injuries.

A method to repair the recurrent laryngeal nerve during thyroidectomy.

Summary: Vocal cord palsy (VCP) is one of the most frequent complications following thyroidectomy. We evaluated the outcomes of intraoperative reconstruction of the recurrent laryngeal nerve (RLN). Of 917 patients who underwent thyroid surgery in a single high-volume general surgery ward between 2000 and 2015, 12 (1.3%) were diagnosed with RLN injury and were retrospectively categorized into 2 groups: group A (n = 5), with intraoperative evidence of iatrogenic transection or cancer invasion of the RLN, and group B (n = 7), with postoperative confirmation of VCP. In group A, immediate microsurgical primary repair of the RLN was performed. Postoperative assessment included subjective ratings (aspiration and voice quality improvement) and objective ratings (perceptual voice quality according to the grade, roughness, breathiness, asthenia and strain [GRBAS] scale, and direct laryngoscopy). In group A, roughness, breathiness and strain were significantly lower at 9 months than at 3 months (p < 0.05). Although larger, multicentre studies are needed, the results suggest potentially excellent postoperative phonatory function after immediate RLN reconstruction.

Recurrent Laryngeal Nerve Liberations and Reconstructions: A Single Institution Experience.

BACKGROUND: Recurrent laryngeal nerve (RLN) palsy rates vary from 0.5 to 10%, even 20% in thyroid cancer surgery. The aim of this paper was to present our experience with RLN liberations and reconstructions after various mechanisms of injury. METHODS: Patients were treated in our institution from year 2000 to 2015. First group (27 patients) had large benign goiters, locally advanced thyroid/parathyroid carcinomas, or incomplete previous surgery of malignant thyroid disease. Second group (5 patients) had reoperations due to RLN paralysis on laryngoscopy. Liberations and reconstructions of injured RLNs were performed. RESULTS: Surgical exploration of central compartment enabled identification of the RLN injury mechanism. Liberations were performed in 11 patients, 2 months to 16 years after RLN injury, by removing misplaced ligations. Immediate or delayed (18 months to 23 years) RLN reconstructions were performed in 21 patients, by direct suture or ansa cervicalis-to-RLN anastomosis (ARA). RLN liberation provided complete voice recovery within 3 weeks in all patients. Patients with direct sutures had better phonation 1 month after reconstruction. Improved phonation was observed 2-6 months after ARA in 43% of patients. CONCLUSIONS: Vocal cords do not regain normal movement once being paralyzed after RLN transection, but they restore tension during phonation by reconstruction. Nerve liberation is a useful method which enables patients with RLN paresis/paralysis a significant improvement in phonation, even complete voice recovery. Reinnervation of vocal cords, using one of the mentioned techniques, should be a standard in thyroid and parathyroid surgery, with aim to improve quality of patient's life.

Surgical Methods and Experiences of Surgeons did not Significantly Affect the Recovery in Phonation Following Reconstruction of the Recurrent Laryngeal Nerve.

BACKGROUND: We reported phonatory recovery in the majority of 88 patients after recurrent laryngeal nerve (RLN) reconstruction. Here we analyzed factors that might influence the recovery, in a larger patient series. METHODS: At Kuma Hospital, 449 patients (354 females and 95 males) underwent RLN reconstruction with direct anastomosis, ansa cervicalis-to-RLN anastomosis, free nerve grafting, or vagus-to-RLN anastomosis; 47.4 % had vocal cord paralysis (VCP) preoperatively. Maximum phonation time (MPT) and mean airflow rate during phonation (MFR) were measured 1 year post surgery. Forty patients whose unilateral RLNs were resected and not reconstructed and 1257 normal subjects served as controls. RESULTS: Compared to the VCP patients, the RLN reconstruction patients had significantly longer MPTs 1 year after surgery, nearing the normal values. The MFR results were similar but less clear. Detailed analyses of 228 female patients with reconstruction for whom data were available revealed that none of the following factors significantly affected phonatory recovery: age, preoperative VCP, method of reconstruction, site of distal anastomosis, use of magnifier, thickness of suture thread, and experience of surgeon. Of these 228 patients, 24 (10.5 %) had MPTs <9 s 1 year after surgery, indicating insufficient recovery in phonation. This insufficiency was also not associated with the factors mentioned above. CONCLUSIONS: Approximately 90 % of patients who needed resection of the RLN achieved phonatory recovery following RLN reconstruction. The recovery was not associated with gender, age, preoperative VCP, surgical method of reconstruction, or experience of the surgeon. Performing reconstruction during thyroid surgery is essential whenever the RLN is resected.

Thyrocricotracheal separation with bilateral recurrent laryngeal nerve transsection: report of a survivor.

Thyrocricotracheal separation is an extremely fatal injury that has not been reported in the literature. Although timely and proper management of this injury is paramount to preserve the patient's life, airway, and voice, its rarity has resulted in a lack of consensus regarding the best management option. We report a case of thyrocricotracheal separation with bilateral recurrent laryngeal nerve transsection caused by a self-inflicted injury, which was treated with reanastomosis in conjunction with transverse laser cordotomy. The patient could achieve both decannulation and a serviceable voice and could return to a normal social life. The present case is the first report of a survivor with thyrocricotracheal separation with bilateral recurrent laryngeal nerve transsection. This findings show that appropriate management of the airway is the first step to ensure a successful outcome, and a step-by-step approach to detect and manage the associated injuries is paramount in cases showing the most severe form of laryngeal trauma.

Ansa to recurrent laryngeal neurorrhaphy in the setting of laryngeal nerve sacrifice: a cadaveric study to evaluate a reconstructive option.

OBJECTIVE: In certain cases, the recurrent laryngeal nerve (RLN) has to be sacrificed. This often results in an inadequate length of residual RLN to be used in a reinnervation procedure. We investigated the length of the distal stump of the RLN from the inferior border of the inferior pharyngeal constrictor muscle (IPCM), where it is frequently compromised, to its entrance into the larynx. Our objective was to determine whether this residual nerve stock was sufficient for margin clearance and neurorrhaphy. STUDY DESIGN: Cadaveric study METHODS: Recurrent laryngeal nerves were identified in fresh frozen cadavers. The IPCM was divided, revealing the distal stump of the RLN, which was measured. RESULTS: Dissection was performed in 20 cadavers (40 nerves). The average length of the right RLN and the left RLN from the IPCM until it entered the larynx was 15mm and 14mm, respectively. All residual RLN remnants were of sufficient length for neurorrhaphy. CONCLUSION: Concomitant RLN reinnervation procedures in the setting of nerve sacrifice are not well described. A barrier to reinnervation in this setting may be insufficient residual nerve length for a neurorrhaphy. Often, when the RLN is sacrificed intraoperatively either iatrogenically or due to tumor invasion, it is close to the cricoarytenoid joint, at the inferior border of the IPCM. This study demonstrates that by splitting the IPCM, sufficient length can be obtained for neurorrhaphy.

Transition of myosin heavy chain isoforms in human laryngeal abductors following denervation.

The objective of this study was to investigate the myofiber subtype transition of human posterior cricoarytenoid (PCA) muscle after the injury to recurrent laryngeal nerve (RLN). PCA muscle specimens were obtained from 38 bilateral vocal fold paralysis patients underwent arytenoidectomy. According to the duration of RLN injury, all the cases were divided into five denervation groups: 6-12 months, 1-2, 2-3, 3-6, and >6 years. The normal PCA muscles from total laryngectomy patients were chosen as controls. Immunofluorescence was adopted to detect the expression level of myosin heavy chain (MHC)-I and MHC-II in PCA muscle. Quantitative real-time PCR was also used to assess the transcriptional level of MHC subtypes (MHC-I, MHC-IIa, MHC-IIb, MHC-IIx, embryonic-MHC, and peri-natal-MHC). Immunofluorescence showed that MHC-I-positive myofibers in denervation groups were much lower than control group, respectively, while MHC-II-positive myofibers were significantly higher than control group (P < 0.05). With the extension of denervation, the number of MHC-I-positive myofibers gradually decreased, while MHC-II gradually increased and peaked in 1- to 2-year group. Transcriptional level of MHC-I, MHC-IIa, and MHC-IIb in denervation groups significantly down-regulated compared with the control (P < 0.05), respectively. However, MHC-IIx, embryonic-MHC, and peri-natal-MHC significantly up-regulated in all denervation groups, and the highest level was in 1- to 2-year denervation group. Data from the present study demonstrated that the maximum transition of MHC subtypes in human PCA muscles occurred in 1-2 years after denervation, suggesting that laryngeal reinnervation before the occurrence of irreversible transition of MHC subtypes could maintain the structural integrity of laryngeal PCA muscles.

Chronic vocal cord palsy in Thuringia, Germany: a population-based study on epidemiology and outcome.

Although surgical treatment of patients with chronic vocal cord palsy (VCP) is an integral part of clinical routine of otorhinolaryngologists, there is nearly no population-based data published on incidence and efficiency of this surgery country-wide or nation-wide. 1430 patients with chronic VCP were treated in a department of otorhinolaryngology between 2005 and 2010 in Thuringia, Germany. VCP was unilateral and bilateral in 63 and 18%, respectively. The affected side was not documented in 20%. Iatrogenic lesions of the recurrent nerve (42%) and neoplastic infiltration (27%) were the leading etiologies. 192 patients (13%) received surgical treatment. 31% of patient needed more than one surgery. The rate of surgeries was higher for bilateral VCP (p < 0.0001). Vocal cord augmentation was the most frequent surgery for unilateral VCP and posterior cordectomy for bilateral VCP. The complication rate was high (16%), but not different between unilateral and bilateral VCP (p = 0.108). The risk for tracheostomy was higher in the bilateral VCP group (p < 0.0001). Voice improvement was better after treatment of unilateral VCP (p < 0.0001). Breathing improvement was more frequent after bilateral VCP (p = 0.028). Dysphagia did not improve significantly. The rate of better voice, breathing, and swallowing function was higher in patients treated surgically than without surgery (all p < 0.0001). The rate of patients admitted for treatment of vocal fold palsy was 9.9/100,000 habitants. The surgical rate of VCP was 1.38/100,000 habitants. This population-based analysis shows that surgery for VCP is performed with higher incidence than expected effectively, but with relevant risks in daily routine of otorhinolaryngologists.

Tissue-Engineered Implant for Hemilaryngectomy Reconstruction with Recurrent Laryngeal Nerve Injury.

OBJECTIVE: Laryngeal cancer resections often require excision of portions of the larynx along with sacrifice of the ipsilateral recurrent laryngeal nerve (RLN). In such cases, there are no reconstructive options that reliably restore laryngeal function, rendering patients with severe functional impairment. To address this unmet clinical need, we extend our evaluation of a 3-implant mucosal, muscle, cartilage reconstruction approach aimed at promoting functional laryngeal restoration in a porcine hemilaryngectomy model with ipsilateral RLN transection. METHODS: Six Yucatan mini-pigs underwent full-thickness hemilaryngectomies with RLN transection followed by transmural reconstruction using fabricated collagen polymeric mucosal, muscle, and cartilage replacements. To determine the effect of adding therapeutic cell populations, subsets of animals received collagen muscle implants containing motor-endplate-expressing muscle progenitor cells (MEEs) and/or collagen cartilage implants containing adipose stem cell (ASC)-derived chondrocyte-like cells. Acoustic vocalization and laryngeal electromyography (L-EMG) provided functional assessments and histopathological analysis with immunostaining was used to characterize the tissue response. RESULTS: Five of six animals survived the 4-week postoperative period with weight gain, airway maintenance, and audible phonation. No tracheostomy or feeding tube was required. Gross and histological assessments of all animals revealed implant integration and regenerative remodeling of airway mucosa epithelium, muscle, and cartilage in the absence of a material-mediated foreign body reaction or biodegradation. Early voice and L-EMG data were suggestive of positive functional outcomes. CONCLUSION: Laryngeal reconstruction with collagen polymeric mucosa, muscle, and cartilage replacements may provide effective restoration of function after hemilaryngectomy with RLN transection. Future preclinical studies should focus on long-term functional outcomes. LEVEL OF EVIDENCE: NA Laryngoscope, 134:4604-4613, 2024.

Changes in vocal fold gene expression and histology after injection augmentation in a recurrent laryngeal nerve injury model.

OBJECTIVE: To investigate changes in neuroregenerative pathways with vocal fold denervation in response to vocal fold augmentation. METHODS: Eighteen Yorkshire crossbreed swine underwent left recurrent laryngeal nerve transection, followed by observation or augmentation with carboxymethylcellulose or calcium hydroxyapatite at two weeks. Polymerase chain reaction expression of genes regulating muscle growth (MyoD1, MyoG and FoxO1) and atrophy (FBXO32) were analysed at 4 and 12 weeks post-injection. Thyroarytenoid neuromuscular junction density was quantified using immunohistochemistry. RESULTS: Denervated vocal folds demonstrated reduced expression of MyoD1, MyoG, FoxO1 and FBXO32, but overexpression after augmentation. Healthy vocal folds showed increased early and late MyoD1, MyoG, FoxO1 and FBXO32 expression in all animals. Neuromuscular junction density had a slower decline in augmented compared to untreated denervated vocal folds, and was significantly reduced in healthy vocal folds contralateral to augmentation. CONCLUSION: Injection augmentation may slow neuromuscular degeneration pathways in denervated vocal folds and reduce compensatory remodelling in contralateral healthy vocal folds.

Long-Term Outcomes and Revision Rates in Laryngeal Reinnervation.

OBJECTIVES: Nonselective laryngeal reinnervation is an effective procedure to improve voice quality after unilateral vocal fold paralysis. Few studies have captured long-term outcome data, and the revision rate for this operation is currently unknown. The objective of this study is to describe the long-term outcomes and revision rates of unilateral, nonselective reinnervation in pediatric and adult patients. METHODS: Patients who underwent laryngeal reinnervation from 2000 to 2022 with a single surgeon were identified for inclusion. Patients who underwent bilateral, super selective, deinnervation and reinnervation, and/or concurrent arytenoid adduction procedures were excluded. Outcome measures included maximum phonation time [MPT], voice handicap index score [VHI], patient-reported percent normal voice, revision procedures, and complications. Data were compiled and analyzed using paired t-tests, repeated measures analysis of covariance, and binary logistic regression analysis. RESULTS: One hundred thirty-two patients underwent unilateral, nonselective ansa-recurrent laryngeal nerve [RLN] laryngeal reinnervation. Reinnervation significantly improved MPT and patient-reported percentage of normal voice and significantly decreased VHI. Eleven patients underwent revision procedures, corresponding to a revision rate of 8.3%. Additional procedures included medialization laryngoplasty [n = 3], medialization laryngoplasty with arytenoid adduction [n = 3] and injection augmentation greater than 1 year after reinnervation [n = 5]. The only factor associated with the need for additional surgery was time lapse from nerve injury to reinnervation. The overall complication rate was 6.8%; no patient required reintubation or tracheostomy. CONCLUSION: Unilateral, nonselective laryngeal reinnervation can provide reliable improvement in vocal symptoms after recurrent laryngeal nerve injury. The revision rate after laryngeal reinnervation is favorable and comparable to framework surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:3187-3192, 2024.

Recurrent laryngeal nerve transection and anastomosis: rat laryngeal motoneuron survival and effect of the anastomosis site.

OBJECTIVES: We investigated the quantity of recurrent laryngeal nerve motoneurons (RLNMs) that survive after transection and anastomosis of the rat recurrent laryngeal nerve (RLN), as well as the impact of the anastomosis site on RLN regeneration. METHODS: Ten rats underwent right RLN transection and anastomosis. After 16 weeks, Fluoro-Ruby (FR) was applied to the RLN that was transected proximal or distal to the anastomosis site. The brain stems were harvested, and the nucleus ambiguus was evaluated for labeled RLNMs. The RLNM counts were compared to each other and to those from 3 control rats in which FR was applied to an acutely transected RLN. RESULTS: The number of RLNMs that were stained after RLN transection, anastomosis, and regeneration was consistent with the total number of RLNMs in the nucleus ambiguus of control rats. This finding confirms that most RLNMs survived after RLN transection and anastomosis. The quantity of labeled RLNMs was statistically similar whether the FR was applied proximal or distal to the anastomosis, implying that most of the viable axons that were present proximal to the anastomosis crossed into the distal nerve. CONCLUSIONS: Rat RLNMs survive nerve transection, anastomosis, and regeneration. The anastomosis site does not significantly impede axonal regeneration, and most of the axons traverse the anastomosis into the distal nerve.

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.

Microscopic bilateral posterior cordotomy in severe obstructive sleep apnea syndrome with bilateral vocal cord paralysis.

BACKGROUND: Vocal cord paralysis is a rare cause of obstructive sleep apnea syndrome (OSAS). Recurrent laryngeal nerve injury after thyroid gland surgery is one of the leading causes of acquired vocal cord paralysis. REPORT: A 46-year-old woman with OSAS due to bilateral abductor vocal cord paralysis was presented. She had thyroidectomy 30 years ago and had a weak, breathy voice. She had been referred with a history of high-pitched snoring, apnea witnessed by her spouse, and excessive daytime sleepiness for the last 5 years. Full-night polysomnography revealed that her apnea-hypopnea index was 72/h and minimal oxygen saturation level was 81%. There was no REM and deep sleep periods. Ear-nose-throat consultation offered an endoscopic bilateral posterior cordotomy operation via microscopic suspension laryngoscopy (MLS) as a treatment option. CONCLUSIONS: Instead of using a nasal positive airway pressure (nCPAP) device, she was treated surgically. Her OSAS resolved completely within 5 months of the surgery. Her phonation was preserved, and symptoms such as snoring and hypersomnolance disappeared. In OSAS patients with bilateral vocal cord paralysis, MLS-associated bilateral posterior cordotomy can be a choice of treatment as an alternative to nCPAP application.