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.

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.

Functional electrical stimulation following nerve injury in a large animal model.

INTRODUCTION: Controversy exists over the effects of functional electrical stimulation (FES) on reinnervation. We hypothesized that intramuscular FES would not delay reinnervation after recurrent laryngeal nerve (RLn) axonotmesis. METHODS: RLn cryo-injury and electrode implantation in ipsilateral posterior cricoarytenoid muscle (PCA) were performed in horses. PCA was stimulated for 20 weeks in eight animals; seven served as controls. Reinnervation was monitored through muscle response to hypercapnia, electrical stimulation and exercise. Ultimately, muscle fiber type proportions and minimum fiber diameters, and RLn axon number and degree of myelination were determined. RESULTS: Laryngeal function returned to normal in both groups within 22 weeks. FES improved muscle strength and geometry, and induced increased type I:II fiber proportion (p = 0.038) in the stimulated PCA. FES showed no deleterious effects on reinnervation. DISCUSSION: Intramuscular electrical stimulation did not delay PCA reinnervation after axonotmesis. FES can represent a supportive treatment to promote laryngeal functional recovery after RLn injury. Muscle Nerve 59:717-725, 2019.

Recurrent Laryngeal Nerve Morbidity: Lessons from Endoscopic via Bilateral Areola and Open Thyroidectomy Technique.

BACKGROUND AND AIM: Elucidating the mechanism of recurrent laryngeal nerve (RLN) injuries through intraoperative electromyographic (EMG) and laryngeal examination approaches may deepen our knowledge regarding its prevention strategies. To date, no studies have been reported on the mechanism of RLN injury caused by endoscopic thyroidectomy via bilateral areola approach (ETBAA). METHODS: Both intraoperative EMG profiles and postoperative laryngeal examination were used to investigate the mechanisms of RLN injury and compare the safety aspects between ETBAA and open thyroidectomy approach (OTA). RESULTS: This study examined 1420 nerves at risk. The mean follow-up period was 17 ± 4 (range 6-48) months. The incidence of vocal cord paralysis was 4.1% (59/1420). The number of cases with decreased EMG signals and vocal cord palsy was higher in ETBAA group than in OTA group (P < 0.05). The left RLNs in ETBAA group were at higher risk compared to the right nerves. CONCLUSIONS: The results of the current study indicate that ETBAA exhibits higher risk of RLN injury. The topic includes a video.

Recurrent laryngeal nerve injury with incomplete loss of electromyography signal during monitored thyroidectomy-evaluation and outcome.

PURPOSE: During monitored thyroidectomy, a partially or completely disrupted point of nerve conduction on the exposed recurrent laryngeal nerve (RLN) indicates true electrophysiologic nerve injury. Complete loss of signal (LOS; absolute threshold value <100 µV) at the end of operation often indicates a postoperative vocal cord (VC) palsy. However, the evaluation for the injured RLN with incomplete LOS and its functional outcome has not been well described. METHODS: Three hundred twenty-three patients with 522 RLNs at risk who underwent standardized monitored thyroidectomy were enrolled. The RLN was routinely stimulated at the most proximal (R2p signal) and distal (R2d signal) ends of exposure after thyroid resection to determine if there was an injured point on the RLN. Pre- and postoperative VC function was routinely examined. RESULTS: Twenty-nine RLNs (5.6 %) were detected with an injury point. Five nerves had complete LOS and other 24 nerves had incomplete LOS where the R2p/R2d reduction (% of amplitude reduction compared with proximal to distal RLN stimulation) ranged from 22 to 79 %. Postoperative temporary VC palsy was noted in those five RLNs with complete LOS (final vagal signal, V2 < 100 µV) and four RLNs with incomplete LOS (R2p/R2d reduction 62-79 %; V2 181-490 µV). In the remaining 20 nerves with R2p/R2d reduction ≤53 % (V2 373-1623 µV), all showed normal VC mobility. Overall, false negative results were found in two RLNs (0.4 %) featuring unchanged V2 and R2p/R2d but developed VC palsy. CONCLUSIONS: Testing and comparing the R2p/R2d signal is a simple and useful procedure to evaluate RLN injury after its dissection and predict functional outcome. When the relative threshold value R2p/R2d reduction reaches over 60 %, surgeon should consider the possibility of postoperative VC palsy.

Adaptation of Continuous Intraoperative Vagus Nerve Stimulation for Monitoring of Recurrent Laryngeal Nerve During Minimally Invasive Esophagectomy.

INTRODUCTION: Esophagectomy has risk of recurrent laryngeal nerve (RLN) injury. Conventional nerve monitoring has been used to help identify and protect the RLN. A new concept of continuous intraoperative nerve monitoring (CIONM) by stimulation of the ipsilateral vagus nerve has been used in thyroidectomy. The current report describes adapting the CIONM method for use in video-assisted thoracoscopic (VATS) esophagectomy. MATERIALS AND METHODS: The nerve monitor employed is NIM 3.0 with automatic periodic stimulation (Medtronics Inc., USA). Patient is intubated with NIM contact-reinforced EMG endotracheal tube (Medtronics Inc., USA). The operation starts with a left lower neck incision, and the stimulating electrode is secured around the left vagus nerve. The patient is then turned to the left lateral position for VATS esophagectomy. CIONM of the left RLN is achieved by regular stimulation of the left vagus nerve, and intact nerve conduction is detected by the electromyography (EMG) of the left vocalis muscle. The alarm is set to activate when EMG amplitude reduces by 50% or latency prolongs by 10%. RESULTS: Initial experience of ten cases showed that a mean time of 35 min was required to complete the electrode insertion in the neck. There was one event in which there was more than 50% reduction of EMG amplitude that persisted but the patient had no vocal cord paralysis after operation. In another patient, the EMG reduced by 75% and persisted. The patient had temporary vocal cord paralysis. CONCLUSION: CIONM is feasible during VATS esophagectomy and can alert the surgeon of imminent injury to the RLNs, thereby preventing permanent injury.

The Overwhelming Majority but not All Motor Fibers of the Bifid Recurrent Laryngeal Nerve are Located in the Anterior Extralaryngeal Branch.

BACKGROUND: Few small studies reported that motor fibers are located exclusively in the anterior branch of the bifid recurrent laryngeal nerve (RLN). The aim of this study was to investigate the location of the motor fibers to the intrinsic muscles of the larynx among the bifid RLNs, and assess the prevalence of RLN injury with respect to nerve branching in a pragmatic trial. METHODS: This was a prospective cohort study of 1250 patients who underwent total thyroidectomy with intraoperative neural monitoring. The primary outcome was the position of the motor fibers in the bifid nerves. Adduction of the vocal folds was detected by the endotracheal tube electromyography and abduction by finger palpation of muscle contraction in the posterior cricoarytenoid. The secondary outcomes were the prevalence of the RLN branching and the prevalence of RLN injury in bifid versus non-bifid nerves. RESULTS: The bifid RLNs were identified in 613/2500 (24.5%) nerves at risk, including 92 (7.4%) patients with bilateral bifurcations. The motor fibers were present exclusively in the anterior branch in 605/613 (98.7%) bifid nerves, and in both the RLN branches in 8/613 (1.3%) bifid nerves. Prevalence of RLN injury was 5.2 versus 1.6% for the bifid versus non-bifid nerves (p < 0.001), odds ratio 2.98 (95% confidence interval 1.79-4.95; p < 0.001). CONCLUSIONS: The motor fibers of the RLN are located in the anterior extralaryngeal branch in the vast majority of but not in all patients. In rare cases, the motor fibers for adduction or abduction are located in the posterior branch of the RLN. As the bifid nerves are more prone to injury than non-branched nerves, meticulous dissection is recommended to assure preservation of all the branches of the RLN during thyroidectomy.

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.

Diaphragmatic Dysfunction after Thoracic Operations.

The perioperative management of diaphragmatic weakness and phrenic nerve dysfunction is complex, due to varied etiologies and clinical presentations. The factors leading to diaphragmatic weakness may culminate after the operation with transient or persistent respiratory failure. This review discusses diaphragmatic disorders and postoperative respiratory failure caused by unilateral or bilateral diaphragmatic impairment. The origins of neuromuscular weakness involving the diaphragm are diverse, and often lie within the domains of different medical specialties, with only a portion of the condition related to surgical intervention. Consideration of underlying etiologies for any individual patient requires thorough multidisciplinary review. The most important clinical scenarios compounding diaphragmatic weakness, including acute myasthenic states, persistent neuromuscular blockade, and surgical injury to the phrenic nerve or diaphragm, are accessible to attentive surgeons. Awareness of the signs and symptoms of undiagnosed weakness, preoperative pursuit of its diagnosis, knowledge of surgical alternatives to phrenic nerve resection, and cooperative skills in the multidisciplinary management of myasthenia all are crucial to improve patient outcomes.

Microarray Analysis Gene Expression Profiles in Laryngeal Muscle After Recurrent Laryngeal Nerve Injury.

OBJECTIVES: The pathophysiology of recurrent laryngeal nerve (RLN) transection injury is rare in that it is characteristically followed by a high degree of spontaneous reinnervation, with reinnervation of the laryngeal adductor complex (AC) preceding that of the abducting posterior cricoarytenoid (PCA) muscle. Here, we aim to elucidate the differentially expressed myogenic factors following RLN injury that may be at least partially responsible for the spontaneous reinnervation. METHODS: F344 male rats underwent RLN injury (n = 12) or sham surgery (n = 12). One week after RLN injury, larynges were harvested following euthanasia. The mRNA was extracted from PCA and AC muscles bilaterally, and microarray analysis was performed using a full rat genome array. RESULTS: Microarray analysis of denervated AC and PCA muscles demonstrated dramatic differences in gene expression profiles, with 205 individual probes that were differentially expressed between the denervated AC and PCA muscles and only 14 genes with similar expression patterns. CONCLUSIONS: The differential expression patterns of the AC and PCA suggest different mechanisms of reinnervation. The PCA showed the gene patterns of Wallerian degeneration, while the AC expressed the gene patterns of reinnervation by adjacent axonal sprouting. This finding may reveal important therapeutic targets applicable to RLN and other peripheral nerve injuries.

Effects of Functional Electrical Stimulation on Denervated Laryngeal Muscle in a Large Animal Model.

Bilateral vocal fold paralysis (BVCP) is a life-threatening condition that follows injury to the Recurrent Laryngeal nerve (RLn) and denervation of the intrinsic laryngeal musculature. Functional electrical stimulation (FES) enables restoration and control of a wide variety of motor functions impaired by lower motor neuron lesions. Here we evaluate the effects of FES on the sole arytenoid abductor, the posterior cricoarytenoid (PCA) muscle in a large animal model of RLn injury. Ten horses were instrumented with two quadripolar intramuscular electrodes in the left PCA muscle. Following a 12-week denervation period, the PCA was stimulated using a once-daily training session for 8 weeks in seven animals. Three animals were used as unstimulated controls. Denervation produced a significant increase in rheobase (P < 0.001). Electrical stimulation produced a 30% increase in fiber diameter in comparison with the unstimulated control group (33.9 ± 2.6 µm FES+, 23.6 ± 4.2 µm FES-, P = 0.04). A trend toward a decrease in the proportion of type 1 (slow) fibers and an increase in type 2a (fast) fibers was also observed. Despite these changes, improvement in PCA function at rest was not observed. These data suggest that electrical stimulation using a relatively conservative set of stimulation parameters can reverse the muscle fiber atrophy produced by complete denervation while avoiding a shift to a slow (type 1) fiber type.

Effect on laryngeal adductor function of vincristine block of posterior cricoarytenoid muscle 3 to 5 months after recurrent laryngeal nerve injury.

OBJECTIVES: It has been shown in a canine model that a single injection of vincristine into the posterior cricoarytenoid (PCA) muscle at the time of recurrent laryngeal nerve (RLN) injury effectively blocks its reinnervation and results in improved adductor strength. But clinically, such injuries are usually diagnosed weeks or months after onset. Vincristine injection does not affect a muscle that is already innervated; thus, there is a limited time frame following RLN injury during which a vincristine injection could effectively improve ultimate laryngeal adductor functional recovery. A series of delayed injections was performed in a canine model and results assessed. STUDY DESIGN: Animal (canine) experiment. METHODS: The RLN was transected and repaired, and vincristine (0.4 mg) was injected into the PCA muscle at the time of injury (n=12) or 3, 4, and 5 months later (n=8 each study group). Six months after RLN injury, laryngeal adductor function was measured. Results of vincristine injection without RLN injury (n=6) and longer-term (12 months) follow-up for time zero injections (n=4) are also reported. RESULTS: The animals injected at time zero had better adductor function than non-injected controls, as reported previously, and this result was further increased at 12 months. The 3-month delay gave results similar to the time zero group. The 5-month delay group showed no vincristine benefit, and the 4-month delay group gave an intermediate result. Vincristine to the PCA had no effect on adductor function when the RLN was left intact. Plasma levels showed 19% of injected vincristine reached systemic circulation, which was cleared within 69 hours. CONCLUSIONS: Vincristine injection of the PCA muscle after RLN injury, which blocks this antagonist muscle from synkinetic reinnervation, leads to improved laryngeal adductor functional recovery. The window of opportunity to apply this treatment closes by 4 months after RLN injury in the canine model. Human RLN recovery follows a similar time course and can reasonably be expected to have a similar therapeutic window.

The Physiologic Impact of Unilateral Recurrent Laryngeal Nerve (RLN) Lesion on Infant Oropharyngeal and Esophageal Performance.

Recurrent laryngeal nerve (RLN) injury in neonates, a complication of patent ductus arteriosus corrective surgery, leads to aspiration and swallowing complications. Severity of symptoms and prognosis for recovery are variable. We transected the RLN unilaterally in an infant mammalian animal model to characterize the degree and variability of dysphagia in a controlled experimental setting. We tested the hypotheses that (1) both airway protection and esophageal function would be compromised by lesion, (2) given our design, variability between multiple post-lesion trials would be minimal, and (3) variability among individuals would be minimal. Individuals' swallowing performance was assessed pre- and post-lesion using high speed VFSS. Aspiration was assessed using the Infant Mammalian Penetration-Aspiration Scale (IMPAS). Esophageal function was assessed using two measures devised for this study. Our results indicate that RLN lesion leads to increased frequency of aspiration, and increased esophageal dysfunction, with significant variation in these basic patterns at all levels. On average, aspiration worsened with time post-lesion. Within a single feeding sequence, the distribution of unsafe swallows varied. Individuals changed post-lesion either by increasing average IMPAS score, or by increasing variation in IMPAS score. Unilateral RLN transection resulted in dysphagia with both compromised airway protection and esophageal function. Despite consistent, experimentally controlled injury, significant variation in response to lesion remained. Aspiration following RLN lesion was due to more than unilateral vocal fold paralysis. We suggest that neurological variation underlies this pattern.

Neuroregeneration in the nucleus ambiguus after recurrent laryngeal nerve avulsion in rats.

OBJECTIVES: The objective was to investigate neuroregeneration, the origins of newborn cells and the proliferation of neuronal and glial cells in the nucleus ambiguus (NA) after ipsilateral recurrent laryngeal nerve (RLN) avulsion. METHODS: All of the animals received a CM-Dil injection in the left lateral ventricle. Forty-five adult rats were subjected to a left RLN avulsion injury, while 9 rats were used as controls. 5-Bromo-2-deoxyuridine (BrdU) was injected intraperitoneally. Neuron quantification and immunohistochemical analysis were performed in the brain stems at different time points after RLN injury. RESULTS: After RLN avulsion, CM-Dil labeled neural progenitor cells (NPCs) migrated to the ipsilateral NA and differentiated into astrocytes but not into neurons. In the NA, the neuronal cells re-expressed nestin. Only a small number of neuronal and glial cells in the NA showed BrdU immunoreactivity. CONCLUSIONS: After RLN avulsion, the NPCs in the ependymal layer of the fourth ventricle or central canal are activated, migrate to the lesion in the NA and differentiate exclusively into astrocytes. The newborn neural stem cells in the NA may arise from the mature region neurons. The presence of both cell types in the NA may play a role in repairing RLN injuries.

Assessment of Voice Quality and Vocal Cord Paralysis After Endarterectomy.

Introduction: Recurrent laryngeal nerve palsy is a rare but important complication after endarterectomy (CEA). The impact on voice quality after this procedure is also important. The aim of the study was to assess voice quality and vocal cord function after CEA. Material and Methods: 200 patients were enrolled in the study. Inclusion criteria were indications for CEA and patient consent to the procedure. Endoscopic examination of the larynx was performed before the procedure, immediately after the procedure, on the 2nd day after the procedure, then 3 month and 6 months after the procedure. Voice was assessed by maximum phonation time (MPT), GRBAS scale, Voice Handicap Index (VHI) and the Voice-Related Quality of Life (V-RQOL) questionnaire. Results: In the study group, the results on the GRBAS scale were significantly worse and the average MPT was shorter compared to the control group. In the V-RQOL assessment, patients rated their voice as fair or good, significantly more often noticed that they had difficulty speaking loudly and being heard, and that they felt short of air when speaking. In VHI-30, the total score was significantly higher in the study group compared to the control group. Voice disorders after the procedure were reported by 68 patients, while a disorder of the recurrent laryngeal nerve was observed immediately after the procedure in 32 patients. Most vocal cord disorders were transient. Ultimately, 3% of patients were diagnosed with vocal cord paralysis. Conclusion: Cranial nerves paralysis, including the recurrent laryngeal nerve, are a common complication after CEA. Majority the paralysis is transient, but requires appropriate diagnostic and therapeutic procedures. Vocal cord evaluation is a non-invasive and widely available examination and should be performed pre- and postoperatively after all neck surgeries. The incidence of voice disorders after CEA significantly affects the quality of life of patients and requires voice rehabilitation and patient care with psychological support.

Evolution of nerve injury with unexpected EMG signal recovery in thyroid surgery using continuous intraoperative neuromonitoring.

BACKGROUND: Intermittent intraoperative neuromonitoring cannot prevent preparative surgical damage or predict imminent recurrent laryngeal nerve (RLN) damage with subsequent development of loss of electromyogram (EMG) signal during thyroid surgery. In case the nerve is stressed, i.e., from traction near the ligament of Berry, the nerve injury is only detected after it has occurred, not allowing the surgeon to correct the mechanical maneuver and salvage nerve function intraoperatively. METHODS: The unusual clinical scenario of sacrifice of a tumor-infiltrated RLN was used to study real-time evolution of RLN injury caused by mechanical distention. The ipsilateral vagus nerve (VN) was continuously stimulated with a new stimulation probe, and changes in EMG response were correlated with the varying levels of stretch and traction. RESULTS: Mechanical traction induced an intermittent depression of EMG amplitudes as a sign of impaired propagation of axon potentials or synaptic transmission. Prolonged mechanical stress caused a long-lasting depression of EMG response. When the mechanical distention was relieved, neurotransmission was gradually restored, with reappearance of singular muscle depolarization of full magnitude interspersed between the barely detectable deflections in the EMG recording. These responses of full amplitude appeared with increasing frequency, until the regular continuous EMG pattern was completely restored. CONCLUSIONS: Only continuous VN stimulation serves to detect early changes in EMG response that indicate imminent danger to RLN functional integrity and alerts the surgeon to immediately correctable surgical actions, thus possibly preventing nerve damage or transforming damage into a reversible event.

Initial experience with S-shaped electrode for continuous vagal nerve stimulation in thyroid surgery.

BACKGROUND: In thyroid surgery, intra-operative neuromonitoring of the recurrent laryngeal nerve (RLN) and vagal nerve (VN) are performed as an adjunct to the gold standard of optical visualisation of the RLN, to avoid injury of the RLN, and subsequently paralysis of the vocal cords. Intermittent RLN neuromonitoring diminished the temporary RLN palsy rate, but continuous neuromonitoring could have to potential of avoiding any damage. Since no study evaluated continuous vagal stimulation before, the objective of this study was to evaluate continuous neuromonitoring in a clinical setting, to assess its' value in predicting vocal cord injury. METHODS: A single centre prospective study was performed from September 2010 till February 2012, including 100 consecutive thyroidectomies with continuous VN stimulation using an S-shaped electrode. RESULTS: In this study, 100 thyroidectomies (80 total thyroidectomies and 20 hemi-thyroidectomies) were analysed. On 180 nerves at risk (NAR), there were four RLN palsies (2.2 %), of which only one definitive. In the cases with temporary palsies, an intra-operative diminution of the amplitude occurred, recovering partially with release of traction. Loss of signal was seen in all four cases, with an abrupt loss of signal in the definitive one. The RLN function remained intact in the other 176 NAR. CONCLUSION: Continuous neuromonitoring of the VN is accurate and precise in predicting vocal cord palsy. It is of tremendous importance that the vagal electrode is a-traumatic and gives a stable signal. The exact parameters regarding "warning signs" have yet to be determined, but amplitude changes seem to play a major role.

Recurrent laryngeal nerve regeneration through a silicone tube produces reinnervation without vocal fold mobility in rats.

OBJECTIVES: We established an animal model of recurrent laryngeal nerve reinnervation with persistent vocal fold immobility following recurrent laryngeal nerve injury. METHODS: In 36 rats, the left recurrent laryngeal nerve was transected and the stumps were abutted in a silicone tube with a 1-mm interspace, facilitating regeneration. The mobility of the vocal folds was examined endoscopically 5, 10, and 15 weeks later. Electromyography of the thyroarytenoid muscle was performed. Reinnervation was assessed by means of a quantitative immunohistologic evaluation with anti-neurofilament antibody in the nerve both proximal and distal to the silicone tube. The atrophy of the thyroarytenoid muscle was assessed histologically. RESULTS: We observed that all animals had a fixed left vocal fold throughout the study. The average neurofilament expression in the nerve both distal and proximal to the silicone tube, the muscle area, and the amplitude of the compound muscle action potential recorded from the thyroarytenoid muscle on the treated side increased significantly (p < 0.05) over time, demonstrating regeneration through the silicone tube. CONCLUSIONS: Recurrent laryngeal nerve regeneration through a silicone tube produced reinnervation without vocal fold mobility in rats. The efficacy of new laryngeal reinnervation treatments can be assessed with this model.

[Hybrid operation for a posttraumatic saccular aneurysm of the aortic arch].

The article deals with a case report of successful hybrid surgical treatment of a patient presenting with a posttraumatic large false saccular aneurysm of the aortic arch with mediastinal displacement and compression of the left recurrent laryngeal nerve and trachea. The patient was subjected to a hybrid operation, i. e., bypass grafting of the brachiocephalic trunk and the left common carotid artery with a bifurcation prosthesis from the ascending aorta through sternotomy, carotid-vertebral and carotid-subclavian bypass grafting on the left in a combination with endoprosthetic repair of the aortic arch with the stent graft Valiant Thoracic 40 × 224 mm (VAMF 4040c200TE) manufactured by the Medtronic Company. The postoperative period was uneventful followed by rather rapid rehabilitation of the patient. One month after the operation, the clinical state improved considerably. His voice restored virtually completely, and breathlessness disappeared. According to the findings of MSCT angiography, the aneurysmatic cavity is thrombosed, with the stent graft showing no evidence of either dislocation or endoleak. The bifurcation bypass graft is functioning. According to the data of duplex scanning, the anastomoses established on the neck are patent.