Recurrent Laryngeal Nerve Resection Research Articles

Intracordal Injections With Allogenic Cartilage in a Canine Paralyzed Vocal Fold Model: Long-Term Results

To determine whether detergent treated allogenic cartilage can be used as a substitute for autologous cartilage in a canine paralyzed vocal fold model. Twelve canines underwent a right recurrent laryngeal nerve resection with injections of allogenic auricular cartilage (harvested 7 days prior, treated with detergent, and minced), with a hyaluronic acid hydrogel (0.2 mL) into the right thyroarytenoid muscle, and with a pressure syringe under direct laryngoscopy. Two animals were sacrificed and larynges removed at each time point: 1-, 3-, 6-, 12-, 18-, and 24-months post injection. Hematoxylin-eosin and immunohistochemistry for expression of major histocompatibility complex-II (MHC-II) antigen was measured to assess histomorphology and gross volume and loss of antigenicity of the injected allogenic cartilage. Injected allogenic cartilage maintained its position and volume in the vocalis muscle throughout 24 months. Cartilage was characterized with empty lacunae indicating possible loss of viability. Fibrotic changes were noted in the surrounding cartilage. MCH-II antigen was not identified in the perichondrium and/or cartilage. Inflammatory reaction, granuloma, or foreign body reaction was not observed at any time point. These preliminary results suggest that allogenic auricular cartilage grafts treated with detergent are well tolerated and may be an effective material for volumetric augmentation in the paralyzed vocal fold.

Voice Quality after Recurrent Laryngeal Nerve Resection and Primary Reconstruction

Objective: Evaluate clinician and patient perception of voice quality in patients who have undergone resection of the recurrent laryngeal nerve (RLN) and primary operative reconstruction with anastomosis or nerve graft during thyroid surgery. Method: Prospective observational study of 9 patients who underwent primary operative reconstruction of the RLN by the senior author from 2002 to present. Outcome measures included: 1) speech pathologist perception of voice scored using the GRBAS scale, 2) patient perception of voice assessed by the Voice Handicap Index (VHI) questionnaire, and 3) visual laryngeal analysis from videostroboscopy examinations. Results: The RLN was reconstructed with primary anastomosis (4), free nerve graft (3), or vagus-RLN anastomosis (2). Seven patients had voice samples and videostroboscopy examinations obtained at a minimum of nine months from surgery. Six were judged to have slight disturbance of voice based on overall Grade scoring (G = 1). Five rated their voice normal or with a mild degree of severity on the VHI questionnaire (score range, 8-29). Laryngeal analysis revealed the immobile vocal fold in the median, physiologic phonating position with preserved bulk, recovered tension, and glottic closure during phonation. Two patients less than 9 months from surgery had expected severe self perceived voice quality. Conclusion: Primary anastomosis, free nerve grafting, and vagus-RLN anastomosis are viable options for RLN reconstruction. VHI scores are comparable to VHI scores of patients who have undergone silastic medialization laryngoplasty. Patients who undergo resection and immediate reconstruction of the RLN are able to regain self-perceived functional and pleasing voices.

Novel Model to Assess Laryngeal Function, Innervation, and Reinnervation

Laryngeal paralysis remains an unsolved problem, and the behavior of the laryngeal muscles following injury to the native innervation appears to be a function of denervation and reinnervation. The aim of the present study was to develop a reliable, accurate, and multifaceted animal model for study of laryngeal function, innervation, and reinnervation. A spontaneous-breathing anesthesia technique, suspension laryngoscopy, endoscopic evaluation of the rat larynx, and transoral injection of a retrograde neuronal tracer, hydroxystilbamidine (FluoroGold), were developed. We submitted 14 rats to the developed technique to map the brain stem projections of the superior laryngeal nerve and the recurrent laryngeal nerve and to determine the feasibility and accuracy of the endoscopic injection technique. This endoscopic technique provided full evaluation of the rat larynx. We performed transoral endoscopic injection of FluoroGold and transcervical application of the tracer to transected superior laryngeal and recurrent laryngeal nerves in 14 different rats and successfully created a neural projection map for the superior laryngeal nerve, the recurrent laryngeal nerve, and the cervical ganglia. A reliable, accurate model for the characterization of laryngeal function, routes of innervation, and sources of spontaneous reinnervation following recurrent laryngeal nerve resection has been developed. This stable and reproducible model can serve as a dependable tool in future investigations of laryngeal nerve injury and recovery.

Prevention and treatment of recurrent laryngeal nerve injury during operation in patients with thyroid cancer

Objective To investigate the causes, prevention and treatment of recurrent laryngeal nerve (RLN) injury during operation in patients with thyroid cancer. Methods Clinical data of 192 patients undergone thyroidectomy operation were reviewed. Results RLN was exposed during operation in 192 patients. There were 3 cases of RLN injury, then RLN anastomosis was happened immediately during operation. It was significantiy improved in pronunciation after operation. 2 ～ 3 d after surgery, transitory hoarseness was observed in 3 patients. Unilateral RLN resection performed in 1 case with cancer involving RLN. Conclusions There were some causes of RLN injury. Exposure of RLN selectively,delicate operation and thyroid gland surgery specialist were the key point for prevention of the injury of RLN. Once RLN injury occured ,repairing should be performed as soon as possible. Key words: Thyroid neoplasms; Recurrent laryngeal nerve/injury ; Thyroidectomy

Diagnosis and treatment of congenital fourth branchial anomaly

To discuss the anatomic features, clinical presentations, diagnosis, differentiations and treatments of congenital fourth branchial anomaly(CFBA). The clinical data of 8 patients with CFBA were retrospectively analyzed. Of the 8 patients aging from 27 to 300 months (median age: 114 months), 4 male and 4 female; 3 untreated previously and 5 recurrent. All lesions, including 1 cyst, 3 sinus (with internal opening) and 4 fistula, located in the left necks. Three patients presented acute suppurative thyroiditis, 4 deep neck abscesses, and 1 neck lump. Preoperative examinations included barium esophagogram, direct laryngoscopy, ultrasonography, CT, MRI, and so on. The principles of managements were adequate drainage, infection control during acute period and radical surgery during quiescent period. Classic surgical approach consisted of complete excision of branchial lesions, dissection of recurrent laryngeal nerve and partial thyroidectomy. Selective neck dissection was applied in recurrent cases to extirpate branchial lesions, scarrings and inflammatory granuloma. Postoperatively, 1 case was with local incision infection which healed by wound care; 1 case was with temporary vocal cord paralysis which completely recovered 1 month after operation. No recurrence was found in all of 8 cases with follow-up of 13 to 42 months (median: 21 months). CFBA relates closely anatomically with recurrent laryngeal nerve and thyroid grand. The barium esophagogram and direct laryngoscopy are the most useful diagnostic tools. CT and MRI are all beneficial to the diagnosis of CFBA. The treatment key to CFBA is the complete excision of lesion during a quiescent period after inflammatory control, together with the dissection of recurrent laryngeal nerve, partial thyroidectomy and partial resection of lamina of thyroid cartilage (if necessary), which all can decrease the risk of complications and recurrence. For recurrent cases, selective neck dissection is a safe and effective surgical procedure.

The Role of Immediate Recurrent Laryngeal Nerve Reconstruction for Thyroid Cancer Surgery

Unilateral vocal fold paralysis (UVFP) is one of the most serious problems in conducting surgery for thyroid cancer. Different treatments are available for the management of UVFP including intracordal injection, type I thyroplasty, arytenoid adduction, and laryngeal reinnervations. The effects of immediate recurrent laryngeal nerve (RLN) reconstruction during thyroid cancer surgery with or without UVFP before the surgery were evaluated with videostroboscopic, aerodynamic, and perceptual analyses. All subjects experienced postoperative improvements in voice quality. Particularly, aerodynamic analysis showed that the values for all patients entered normal ranges in both patients with and without UVFP before surgery. Immediate RLN reconstruction has the potential to restore a normal or near-normal voice by returning thyroarytenoid muscle tone and bulk seen with vocal fold denervation. Immediate RLN reconstruction is an efficient and effective approach to the management of RLN resection during surgery for thyroid cancer.

Improvement in phonation after reconstruction of the recurrent laryngeal nerve in patients with thyroid cancer invading the nerve

We report vocal improvement after reconstruction of the recurrent laryngeal nerve (RLN) in patients with nerve resection, although vocal cord movement was not restored. These methods are not widely recognized. Direct anastomosis, free nerve grafting, or anastomosis to the ansa cervicalis or the vagus nerves with the RLN were performed in 7, 14, 65, and 2 patients with thyroid cancer invading the RLN, respectively. A total of 51 patients had vocal cord paralysis (VCP) pre-operatively. Maximum phonation time (MPT) and vital capacity (VC) were measured before and 1 year after reconstruction. A total of 34 normal subjects and 27 patients with VCP served as controls. Patients with VCP had significantly shorter MPT values than normal subjects. At 1 year after operation, patients with reconstruction had values of MPT similar to those of normal subjects. Men had significantly longer MPT values than women, but the phonation efficiency index (PEI), defined as the MPT/VC ratio, did not differ by sex. The PEI was significantly less in VCP patients than in normal subjects. Patients with reconstruction achieved PEI values similar to those in normal subjects. Phonation efficiency index values at 1 year after operation was significantly greater than pre-operative PEI and was not affected by the presence or absence of VCP pre-operatively, age, reconstruction method, thickness of suture thread, or use of magnification during the operation. In patients with thyroid cancer requiring RLN resection, RLN reconstruction achieved recovery in phonatory function.

反回神経切除症例に対する音声再建の有用性

Our treatment of choice in voice reconstruction for recurrent laryngeal nerve (RLN) resection is concurrent nerve reconstruction. If this is not possible, we secondarily inject fat. We studied postoperative voice function and the feasibility of this voice reconstruction treatment strategy. Subjects were 39 patients with advanced thyroid cancer having the primary lesion resected together with RLN between 2001 and 2007. Of these 39, 9 underwent concurrent reconstruction by directly anastomosing the ansa cervicalis to the peripheral RLN. Fat was secondarily injected in 25 and 5 did not undergo any reconstruction. We found that: 1) Postoperative maximum phonation time (MPT), mean flow rate (MFR) and pitch perturbation quotient (PPQ) in the direct anastomosis group were significantly better than in the nonreconstruction group (p < 0.05). 2) Postoperative MPT, MFR, and PPQ in the fat injection group were significantly better than in the nonreconstruction group (p < 0.05). 3) MPT in the fat injection group was significantly better than in the direct anastomosis group one month postoperatively (p = 0.007), although this finding was reversed six months postoperatively (p = 0.08). 4) MFR in the fat injection group tended to be better than the direct anastomosis group one month postoperatively (p = 0.1), although this finding was reversed six months postoperatively (p = 0.1). We thus recommend concurrent voice reconstruction by direct anastomosis in conjuction with nerve resection.

Effects of Long‐Term Denervation on the Rat Thyroarytenoid Muscle

To determine the effects of long-term denervation on the rat thyroarytenoid (TA) muscle and neuromuscular junctions. A quantitative histologic assessment of the TA muscle after long-term denervation. Thirty Wistar rats were euthanized 10, 18, 26, 42, and 58 weeks after left recurrent laryngeal nerve resection. The areas of the entire muscle and individual muscle fibers were evaluated using hematoxylin-eosin staining, and neuromuscular junctions were detected by immunohistochemistry. Changes after denervation were evaluated by comparing the treated (T) and untreated (U) sides (T/U ratio). The ratio of the number of nerve terminals (NTs) to that of acetylcholine receptors (AChRs) (NT/AChR ratio) was also assessed. The average T/U ratio for the entire muscle area of the denervation groups ranged between 61.1% and 72.5% and did not differ significantly. Similarly, the T/U ratios for the individual muscle fiber area ranged between 45.0% and 51.9%, and the differences were not significant. The T/U ratio of AChRs at 58 weeks (35.3 +/- 20.2%) was significantly lower than that at 10 weeks (76.3 +/- 9.0%; P < .01). The NT/AChR ratios ranged between 30.3% and 35.6% and did not differ significantly among the denervation groups. The entire TA muscle area, individual muscle fiber area, and NT/AChR ratio did not decrease with long-term denervation. Thus, the TA muscle may retain an ability to receive regenerating nerve axons. However, the ability of the TA muscle to receive nerve axons may deteriorate after an excessively long denervation period because the T/U ratio of AChRs decreased with long-term denervation.

Thymoma appearing 10 years after an extended thymectomy for myasthenia gravis

Occurrence of thymoma after an extended thymectomy through a full median sternotomy for nonthymomatous thymectomy has been very rarely reported. A 60-year-old male patient who had myasthenia gravis (MG) for 11 years had an extended thymectomy operation with a pathology of thymic hyperplasia and developed a mass in the aortopulmonary window. We resected the mass via anterior left thoracotomy by dividing the ductus arteriosus and mobilizing the aorta. Cord vocal augmentation procedure was done due to the resection of the left recurrent laryngeal nerve.

Histologic Study of an Autologous Fat Graft in the Larynx of Dogs With Unilateral Vocal Fold Paralysis

To determine the histologic finds of autologous fat graft (AFG) in 24 paralyzed canine left vocal folds 12 weeks after introduction. Animal model. Experimental prospective study. Twenty-four mongrel dogs of both genders weighing 15 to 20 kg were divided into three study groups (SGs) of eight dogs each, whose larynges were grafted by vocal fold lipoinjection (VFL-SGA), vocal fold lipoinjection plus insulin (VFLI-SGB), and by fat graft medialization laryngoplasty (FGML-SGC), respectively, and observed for 12 weeks, followed by immediate sacrifice. All 24 dogs were submitted to left vagal and recurrent laryngeal nerve resection. All animals were confirmed to have a left vocal fold paralysis four weeks later, when 2 mL of autologous fat graft were placed inside the left paraglottic space. The larynges were removed at pre-established times and, after they were studied for remaining fat graft volume by magnetic resonance imaging, they were studied histologically to evaluate the influence of the different techniques on the histologic behavior of the graft. Each of the three study groups had its specific finds for fat graft detection and fat absorption, and its characteristics identified and compared statistically. The groups were not statistically different. The histologic findings for the AFG applied to a vocal fold were similar in groups VFL-SGA, VFLI-SGB and FGML-SGC 12 weeks after grafting, with no statistically significant differences between groups, and revealed an almost total loss of the grafted fat.

Autologous Fat Graft Absorption in Unilateral Paralyzed Canine Vocal Folds

The objective of this experimental prospective study on an animal model was to determine the rate of autologous fat graft absorption in 24 paralyzed canine left vocal folds 12 weeks after introduction. Forty mongrel dogs of both sexes weighing 15 to 20 kg were divided into three study groups (SGs) of eight dogs each whose larynges were grafted by vocal fold lipoinjection (VFL-SGA), vocal fold lipoinjection plus insulin (VFLi-SGB), and by fat graft medialization laryngoplasty (FGML-SGC) and observed for 12 weeks. Two control groups (CGs) of eight dogs each were submitted to fat graft medialization laryngoplasty (FGML-CG1) and by vocal fold lipoinjection (VFL-CG2), respectively, followed by immediate killing. All 40 dogs were submitted to left vagal and recurrent laryngeal nerve resection. All animals were confirmed to have a left vocal fold paralysis 4 weeks later when 2 mL of autologous fat graft was placed inside the left paraglottic space. The larynges were removed at preestablished times and studied for remaining fat graft volume by magnetic resonance imaging. The mean volume obtained by imaging were 1.9388 mL for CG1, 1.0476 mL for CG2, 0.1924 mL for VFL, 0.336 mL for VFLi, and 0.565 mL for FGML. CG1 and CG2 did not differ significantly from one another but differed from the SGs, with statistical analysis suggesting a lower absorption of the fat graft in FGML. The absorption rate was 82% in SGA, 68% in the SGB, and 71% in SGC.

Spontaneous Laryngeal Reinnervation after Recurrent Laryngeal or Vagus Nerve Injury

The status of innervation in patients with laryngeal paralysis is somewhat controversial. Electromyographic activity has been frequently documented in the laryngeal muscles of patients with laryngeal paralysis, and animal experiments report a strong propensity for reinnervation after laryngeal nerve injury. However, a study of intraoperative electromyography performed in patients during reinnervation surgery failed to document activity with stimulation of the recurrent laryngeal nerve (RLN). Noting the long-observed differences in the symptoms of patients with vagus nerve injury and those with RLN injury, I hypothesized that reinnervation is influenced by the site of nerve injury. Cats were sacrificed at various intervals after resection of 1 cm of either the RLN or the vagus nerve, without any attempt to repair the nerve. Four months after RLN resection, distal nerve biopsy revealed unmyelinated axons scattered through fibrous tissue. By 6 months, myelinated axons were organized, and electromyographic and histologic examination showed preferential reinnervation of the thyroarytenoid muscle. After vagotomy, the RLN was fibrotic and no axons were present. Both the thyroarytenoid and posterior cricoarytenoid muscles were fibrotic and had no electromyographic activity. The results confirm the strong propensity for laryngeal reinnervation after RLN injury, but not after vagus nerve injury. Preferential reinnervation of adductor muscles may account for a medial position of the paralyzed vocal fold.

ポリープ様声帯に片側反回神経麻痺が合併したことで呼吸困難を来した1例

We reported on a case of Reinke's edema with dyspnea following resection of the right recurrent laryngeal nerve during surgery for thyroid papillary carcinoma. A 55-year-old female, who was a smoker, presented with a greater than 20-year-history of hoarseness of the voice, without dyspnea. She was diagnosed as having type III Reinke's edema according to Yonekawa's classification of Reinke's edema.She had undergone total thyroidectomy with modified selective neck dissection for thyroid papillary carcinoma involving right vocal cord, at the Department of Surgery, Kitasato University Hospital. The right vocal cord was fixed at the paramedian position. The patient had developed dyspnea transiently for a few days. Subsequently, she began to suffer from dyspnea upon exertion or when she developed a cold. The patient was diagnosed as having Reinke's edema. The dyspnea disappeared after endolaryngeal microsurgery. The right vocal cord was fixed at the median position, the mean air flow rate improved, and the fundamental frequency of her voice was higher than before the operation.

Nimodipine and Microsurgery Induced Recovery of the Vocal Cord after Recurrent Laryngeal Nerve Resection

Transection of the recurrent laryngeal nerve leads to permanent palsy of the vocal cord. Experimental studies have confirmed that nimodipine increases the pace of axonal regeneration. We present a case of a 19-year-old male, suffering a thyroid cancer disease, who was subjected to unilateral resection of the recurrent laryngeal nerve during surgery. The nerve was repaired with a nerve graft and the patient further treated with nimodipine for 3 months. Evaluation of the patient showed normalization of voice, movement of the vocal cord on the injured side, and electromyography evidence of reinnervation of the larynx muscles at 15 months after surgery.

Neuronal Survival and Glial Reactions after Recurrent Laryngeal Nerve Resection in the Rat

Complete axonal injury to the recurrent laryngeal nerve (RLN) leads to permanent loss of coordinated function of the intrinsic muscles of the larynx. The aim of the present study was to investigate retrograde reactions, neuronal survival, and glial reactions in the nucleus ambiguus after a distal resection of the RLN to evaluate the potential need for neuroprotective substances. A segment of the left RLN was resected in 31 adult rats. Before sacrifice of the animals at 2 to 28 days postlesion, the motor neurons in the nucleus ambiguus were retrogradely traced by the use of Fluorogold. Brainstems were isolated and processed for neuron quantification and immunohistochemical analysis. Neuron counts were performed in the nucleus ambiguus on serial sections. Glial reactions were investigated in the nucleus ambiguus using immunohistochemistry. No decrease in the number of motor neurons in the nucleus ambiguus could be demonstrated up to 1 month postlesion. Astroglia and microglia showed increased immunoreactivity at 7 to 14 days postinjury, followed by a slight decline in glial reaction. Microglia revealed no signs of transformation into macrophages during the study period, further indicating the absence of neuronal loss. Neuronal death does not occur within 1 month postlesion as a result of resection of the RLN in the adult rat, and neuroprotective substances should therefore be of minor value after RLN injury. Glial reactions appear in a similar fashion as after other peripheral nerve lesions not causing neuronal loss.

Nerve-muscle transplantation to the paraglottic space after resection of recurrent laryngeal nerve.

To evaluate a new method of nerve-muscle transplantation (NMT) to the paraglottic space after resection of the recurrent laryngeal nerve (RLN) during surgery for thyroid cancer. Review of nine consecutive patients with RLN paralysis caused by the thyroid cancer before surgery. After the usual extirpation of the thyroid cancer with concomitant removal of the RLN, the lower part of the sternohyoid muscle approximately 1 cm in width and 2 cm in length with the ansa cervicalis nerve connected was inserted into the paraglottic space by way of anterior retraction of the thyroid ala with the inferior horn cut off. When the muscle or the nerve was adhesive to the cancer, the nerve-muscle on the opposite side was used with transfer through the space under the thyrohyoid muscles and the superior horn of thyroid ala. The voice quality was good or fair after surgery. In most patients, the maximum phonation time was 10 seconds or longer, and the mean flow rate was lower than 200 mL/s. The vocal functions were good immediately after surgery and maintained good values for 2 years or more after surgery. Vocal fold atrophy was not found in any patient. When the RLN is resected during surgery for thyroid cancer end-to-end anastomosis of the nerve is impossible, NMT to the paraglottic space is a useful method for preserving good voice and preventing atrophy of the vocal fold.

The role of ansa-to-recurrent-laryngeal nerve anastomosis in operations for thyroid cancer.

To study the recovery in phonation after reconstruction of the recurrent laryngeal nerve (RLN) in patients whose thyroid cancer was invading the nerve, and to evaluate the role of ansa cervicalis to RLN anastomosis (ARA) in operations for thyroid cancer. Retrospective study. University hospital and private thyroid clinic hospital, Japan. 34 patients with thyroid cancer who underwent reconstruction of unilateral RLN and 331 consecutive patients operated on for thyroid cancer. Reconstruction was direct anastomosis (DA), free nerve grafting (FNG), vagus-RLN anastomosis (VRA) or ARA, including anastomosis behind the thyroid cartilage. Maximum phonation time (34 normal subjects and 26 patients with vocal cord paralysis served as controls), laryngoscopic examination, and the ratio of reconstruction in patients who needed resection of the RLN. The maximum phonation time started to increase rapidly 2-5 months postoperatively in most cases as the patients' voices recovered, and 12 months after reconstruction was significantly longer than in those patients with vocal cord paralysis (P < 0.0001). It was comparable to that of the normal subjects, although the reinnervated cords were fixed in the median. The number of reconstructions in the series of 331 patients increased from 18% to 82% after we started doing ARA with the meticulous technique of anastomosis inside the thyroid cartilage. ARA is as effective as DA or FNG in improving phonation in patients who need resection of a unilateral RLN. As ARA has several advantages over FNG it has a definite place in operations for thyroid cancer.

＜音声からみた反回神経麻ひ治療法の評価＞神経筋移植術

＜音声からみた反回神経麻ひ治療法の評価＞神経筋移植術

Lung surgery: identifying the subgroup at risk for sputum retention.

Sputum retention after lung surgery is a potentially lethal condition, which can progress to atelectasis, pneumonia and respiratory failure requiring ventilatory support. Previous studies have concentrated on the treatment of postoperative respiratory complications but few have studied the risk factors for sputum retention. This prospective study was designed to identify the risk factors which may lead to the development of sputum retention after lung surgery. Three hundred sixty-one patients underwent lung surgery between January 1997 and December 1999 in a specialist Thoracic Surgery Unit (pneumonectomy, lobectomy, wedge or segmental resection, bullectomy, etc). Preoperative and intraoperative data collected prospectively included potential risk factors: chronic obstructive airway disease (COAD), forced expiratory volume in 1 s (FEV1)<50%, current smokers, ischaemic heart disease (IHD), cerebrovascular disease (CVA), resection of phrenic or recurrent laryngeal nerve, or absence of regional analgesia. Univariate and multivariate analysis was performed. Sputum related complications occurred in 108 patients (30%). There were 17 deaths of which nine were due to complications related to sputum retention. Univariate analysis confirmed current smokers (n=128), COAD (n=103), IHD (n=41), prior history of CVA (n=16), FEV1<50% (n=48), and absence of regional anaesthesia as significant risk factors (P<0.01). The multivariate analysis confirmed current smokers, IHD and absence of regional anaesthesia as risk factors. A subgroup of lung surgery patients at high risk for postoperative sputum retention can be predicted by the presence of one of the following criteria: current smokers, history of COAD, CVA, or IHD, and absence of regional analgesia. Prophylactic measures should be considered in this group to reduce the incidence of sputum retention.