Visual and electrophysiological identification of the external branch of superior laryngeal nerve in redo thyroid surgery compared with primary thyroid surgery

PURPOSE: Thyroid reoperations are surgically challenging because of significant anatomical variance. Visual and functional identification of the external branch of the superior laryngeal nerve (EBSLN) were studied in 2 groups of patients who underwent primary and redo thyroid surgery. METHODS: This study was conducted on 200 patients: 100 patients with redo and 100 patients with primary thyroid surgery. In addition to visual identification, nerve branches were functionally identified by intraoperative nerve monitoring (IONM). Visual, functional, and total identification rates of the EBSLN in both primary and redo surgery were determined and compared between the 2 groups. RESULTS: We attempted to identify 138 and 170 EBSLNs at risk in redo and primary surgery, respectively. Visual identification rates were 65.3% and 30.4% (P < 0.001) in primary and redo surgery groups, respectively. In total, 164 (96.5%) and 97 EBSLNs (70.3%) were identified in primary and redo surgery, respectively (P < 0.001), including the use of IONM. In primary surgery group, 53 nonvisualized EBSLNs of 164 identified nerves (32.3%) were determined by IONM alone. In redo surgery group, 55 of 97 identified nerves (56.7%) were determined by IONM alone (P < 0.001). CONCLUSION: Both visual and total identification rates of the EBSLN are significantly decreased in reoperative thyroidectomy. IONM increases the total identification rate of the EBSLN in primary and redo thyroid surgery. Electrophysiological monitoring makes a substantial contribution to the identification of the EBSLN both in primary and especially in redo thyroid surgery.

O tubérculo de Zuckerkandl pode auxiliar na localização do nervo laríngeo inferior durante tireoidectomias? / Can the Zuckerkandl tubercle assist in the location of the inferior laryngeal nerve during thyroidectomies?

RESUMO Objetivo: avaliar se a projeção lateral da glândula tireoide, chamada tubérculo de Zuckerkandl (TZ), pode auxiliar o cirurgião na identificação do nervo laríngeo inferior durante a tireoidectomia convencional aberta. Métodos: estudo prospectivo de 51 pacientes submetidos à tireoidectomia, com um total de 100 lobos tireoidianos ressecados, e observação da presença ou não do TZ em dimensões suficientes para ser identificado sem magnificação de imagem, suas dimensões de base e altura, sua localização na glândula e sua relação anatômica com o nervo laríngeo inferior. Resultados: o TZ estava presente em 68 dos 100 lobos de tireoide analisados (68%). A dimensão média da base foi 6,7mm no lado direito e 7,1mm no lado esquerdo, e a altura média foi 5,7mm no lado direito e 6,1mm no lado esquerdo. Na maioria dos lobos estudados, o tubérculo tinha altura mínima de 5mm (55,9%) sem diferença significativa entre o lobo direito e esquerdo da glândula tireoide. Durante a cirurgia, 100% dos TZ identificados estavam anteriores ao nervo laríngeo inferior, imediatamente abaixo da entrada do nervo na laringe. Conclusão: o TZ é bastante frequente e em dimensões suficientes para ser usado como referência anatômica na localização intraoperatória do nervo laríngeo inferior, próximo à sua entrada na laringe, junto com as demais referências anatômicas.

ABSTRACT Objective: to evaluate whether the lateral projection of the thyroid gland, called Zuckerkandl's tubercle (ZT), can assist the surgeon in identifying the inferior laryngeal nerve during conventional open thyroidectomy. Methods: we conducted a prospective study with 51 patients submitted to thyroidectomy, with a total of 100 resected thyroid lobes, and observed the presence or absence of ZT in sufficient dimensions to be identified without image magnification, its base and height, its location in the gland, and its anatomical relationship with the inferior laryngeal nerve. Results: ZT was present in 68 of the 100 thyroid lobes analyzed (68%). The mean base was 6.7mm on the right side and 7.1mm on the left side, and the average height was 5.7mm on the right side and 6.1mm on the left side. In most of the lobes studied, the tubercle had a minimum height of 5mm (55.9%), with no significant difference between the right and left lobes of the thyroid gland. During surgery, 100% of the identified ZTs were anterior to the inferior laryngeal nerve, just below the nerve entry in the larynx. Conclusion: the ZT is a quite frequent entity and large enough to serve as an intraoperative anatomical reference for the inferior laryngeal nerve, next to its entry in the larynx, along with other anatomical references.

Principles and strategies for the prevention and treatment of parathyroid and larynge-al nerve injuries during thyroid surgery / 中国肿瘤临床

Surgery is the major treatment option for malignant tumors and some benign neoplasms of the thyroid, most of which are differentiated thyroid carcinoma. Despite the progresses that have been made in surgical techniques, iatrogenic injuries of the parathy-roid and laryngeal nerves, including superior and recurrent laryngeal nerves, could not be completely avoided in the surgical manage-ment of thyroid tumors. In this review, the causes of intraoperative injuries of parathyroid and laryngeal nerves are systematically ana-lyzed with respect to types and extents of surgical operations, changes in topical anatomy, and secondary thyroid surgeries. The princi-ples and strategies for protecting and restoring injuries of the parathyroid and laryngeal nerves are also elucidated for the effective prevention and adequate treatment of these major complications in the thyroid surgery.

Comparison of Clinical Characteristics Between Patients With Different Causes of Vocal Cord Immobility

OBJECTIVE: To analyze the clinical characteristics between neurogenic and non-neurogenic cause of vocal cord immobility (VCI). METHODS: The researchers retrospectively reviewed clinical data of patients who underwent laryngeal electromyography (LEMG). LEMG was performed in the bilateral cricothyroid and thyroarytenoid muscles. A total of 137 patients were enrolled from 2011 to 2016, and they were assigned to either the neurogenic or non-neurogenic VCI group, according to the LEMG results. The clinical characteristics were compared between the two groups and a subgroup analysis was done in the neurogenic group. RESULTS: Among the 137 subjects, 94 patients had nerve injury. There were no differences between the neurogenic and non-neurogenic group in terms of demographic data, underlying disease except cancer, and premorbid events. In general characteristics, cancer was significantly higher in the neurogenic group than non-neurogenic group (p=0.001). In the clinical findings, the impaired high pitched ‘e’ sound and aspiration symptoms were significantly higher in neurogenic group (p=0.039 for impaired high pitched ‘e’ sound; p=0.021 for aspiration symptoms), and sore throat was more common in the non-neurogenic group (p=0.014). In the subgroup analysis of neurogenic group, hoarseness was more common in recurrent laryngeal neuropathy group than superior laryngeal neuropathy group (p=0.018). CONCLUSION: In patients with suspected vocal cord palsy, impaired high pitched ‘e’ sound and aspiration symptoms were more common in group with neurogenic cause of VCI. Hoarseness was more frequent in subjects with recurrent laryngeal neuropathy. Thorough clinical evaluation and LEMG are important to differentiate underlying cause of VCI.

Oncoplastic Thyroid Surgery Using A Bilateral Axillo-Breast Approach

Since the first use of the robot da Vinci system for thyroid surgery in 2007, robotic thyroidectomy (RT) via a bilateral axillo-breast approach (BABA) has become a popular surgical alternative for patients who wish to avoid scars on the neck. BABA RT provides excellent cosmetic satisfaction with surgical safety and oncologic completeness. Recently, the use of BABA RT has expanded beyond benign thyroid nodules and small-sized papillary thyroid carcinoma (PTC) to Graves' disease, relatively large PTCs, and PTC with lateral neck metastasis. Unfortunately, there are concerns about the use of this procedure for these additional indications. This review article summarizes postoperative outcomes of BABA RT for thyroid carcinoma, including quality of life, as well as expanding indications for BABA RT.

Intraoperative neuromonitoring of the external branch of the superior laryngeal nerve during robotic thyroid surgery: a preliminary prospective study

PURPOSE: The aim of this study was to evaluate the feasibility of monitoring external branch of the superior laryngeal nerve (EBSLN) during robotic thyroid surgery. METHODS: A total of 10 patients undergoing bilateral axillo-breast approach (BABA) robotic thyroid surgery were enrolled. The nerve integrity monitor (NIM Response 2.0 System) was used for EBSLN monitoring. We performed voice assessments preoperatively and at 1 and 3 months postoperatively using Voice Handicap Index-10 (VHI-10), maximal phonation time (MPT), phonation efficient index (PEI), and laryngeal electromyography (EMG). RESULTS: A total of 19 EBSLNs were at risk and 14 EBSLNs (73.7%) were identified using neuromonitoring. VHI-10 showed a change of voice over time (0.1 vs. 3.6 vs. 1.3); however, this was not statistically significant. VHI-10 scores normalized at 3 months postoperatively compared to the preoperative scores. MPT (a) (16.0 vs. 15.6 vs. 15.4), and MPT (e) (20.1 vs. 15.4 vs. 18.5) showed no significant differences preoperatively compared to the values obtained 1 and 3 months postoperatively. There was a significant change of PEI over time (4.8 vs. 1.1 vs. 4.6) (P = 0.036); however, the values normalized at 3 months postoperatively. Laryngeal EMG results showed 4 cases (21.2%) of neuropathy of EBSLNs at 1 month postoperatively, and electrodiagnostic studies revealed nearly complete recovery of the function of EBSLNs in 4 patients at 3 months postoperatively CONCLUSION: It is suggested that neuromonitoring of EBSLNs during BABA robotic thyroid surgery is feasible and might be helpful to preserve voice quality.

Anatomic relation between the external branch of the superior laryngeal nerve and the thyroid gland / Relação anatômica entre o ramo externo do nervo laríngeo superior e a glândula tireoide

AIM: This prospective study investigated the anatomic relations between the external branch of the superior laryngeal nerve (EBSLN), the superior thyroid artery (STA) and the thyroid gland in human cadavers. MATERIAL AND METHODS: Twenty-two human cadavers aged over 18 years old, less than 24 hours after death. RESULTS: The mean distance between the EBSLN and the superior pole of the thyroid gland was 7.68 ±3.07 mm. A tangent to the inferior edge of the thyroid cartilage between the EBSLN and the STA measured 4.24 ±2.67 mm. A line from the intersection of the EBSLN - related to the STA - to the superior pole of the thyroid gland measured 9.53 ±4.65 mm. A line from the EBSLN to the midline of the most caudal point of the thyroid cartilage measured 19.70 ±2.82 mm. A line from the RENLS to the midline on the most cranial point of the cricoid cartilage was 18.35 ±3.66 mm. CONCLUSION: There is a variable proximity relation between the EBSLN and the superior pole of the thyroid gland; this distance ranges from 3.25 to 15.75 mm. There was no evidence of significant variation between the measures in the ethnic groups comprising the sample.

OBJETIVO: Descrever, prospectivamente, a relação anatômica entre o ramo externo do nervo laríngeo superior (RENLS), a artéria tireoidea superior (ATS) e a glândula tireoide em cadáveres humanos. MATERIAL E MÉTODO: Foram dissecados 22 cadáveres humanos com idade superior a 18 anos, com menos de 24 horas de pós-morte. RESULTADOS: A medida entre o RENLS e o polo superior da glândula tireoide foi 7,68 +/- 3,07mm; entre o RENLS e a ATS foi de 4,24 +/- 2,67mm numa linha tangente ao bordo inferior da cartilagem tireoide; entre o cruzamento da ATS com o RENLS e o polo superior tireoidiano foi 9,53 +/- 4,65mm; entre o RENLS e a linha mediana do pescoço no ponto mais caudal da cartilagem tireoide foi 19,70 +/- 2,82mm; e entre o RENLS e a linha mediana do pescoço no ponto mais cranial da cartilagem cricoide foi 18,35 +/- 3,66mm. CONCLUSÕES: Há uma relação de proximidade variável entre o RENLS e o polo superior da glândula tireoide, variando de 3,25 a 15,75mm. Não constatou-se variações significativas entre as medidas para as diferentes etnias que compõem a amostra.

Análise retrospectiva das tireoidectomias realizadas por residentes de cirurgia geral em hospital universitário / Retrospective analysis of the thyroidectomies performed by general surgery resident in a university hospital

Introdução: Com o objetivo de avaliar as complicações das tireoidectomias realizadas no Hospital Geral do Grajaú, da Faculdade de Medicina da UNISA, durante o período de novembro de 2000 a agosto de 2003, foram analisados retrospectivamente 105 prontuários. Métodos: Todas as cirurgias foram realizadas pelo residente do segundo ano de Cirurgia Geral sob a supervisão de um especialista. Os pacientes foram analisados de acordo com o gênero, idade, duração média da cirurgia, tempo de internação pós-operatório e complicações apresentadas. Resultados: Na série estudada, 85,7% dos pacientes (90 casos), era do gênero feminino. A idade média dos pacientes foi de 50,5 anos, tendo um predomínio de doenças benignas (84% dos casos). A tireoidectomia total foi realizada em 77,1% dos pacientes (81 casos) e 96% dos pacientes receberam alta em até 48 horas após a cirurgia. As complicações encontradas foram: hipocalcemia definitiva em 0,95% (um caso); paralisia transitória do nervo laríngeo recorrente em 2,85% (três casos) e definitiva em 1,9% (dois casos); hematoma com posterior necessidade de reabordagem em 1,9% (dois casos) e desenvolvimento de hipotireoidismo em 50% dos casos que foram submetidos à tireoidectomia não total e nenhum óbito. Conclusão: A tireoidectomia é um procedimento com baixa morbimortalidade, sendo segura, mesmo quando realizado por cirurgiões em treinamento, desde que sob a supervisão direta de um especialista.

Introduction: In order to evaluate the thyroidectomies done in Grajaú General Hospital - UNISA - Medical University from November, 2000 to August, 2003, 105 patients were retrospectively analyzed. Methods: All surgeries were performed by the general surgery 2nd year resident under a specialist supervision. The patients were analyzed according to the gender, age, average duration of the surgery, postoperative permanence into the hospital, and diagnosed complication. Results: In the analyzed series, 85.7% of the patients (90 cases), were women. The age average was 50.5 years-old with a predominance of benign pathology (84.4% of the cases). The total thyroidectomy was performed in 77.1% (81 cases) and 96% of the patients were discharged from hospital in 48 hours after surgery. The following complications were found: definitive hypocalcemia in 0.95% (1 case); transitory palsy of the laryngeal nerve in 2.85% (3 cases); definitive palsy of the laryngeal nerve in 1.9% (2 cases); hematoma with posterior need of reoperation in 1.9% (2 cases); development of hypothyroidism in 50% of the cases which underwent to non total thyroidectomy. There was no death. Conclusion: The thyroidectomy is a low morbimotality procedure and it is safe, even when performed by surgeons in training, since under straight specialist supervision.

Análise quantitativa das fibras mielínicas dos nervos laríngeos em humanos de acordo com a idade / Quantitative analysis of myelinic fibers in human laryngeal nerves according to age

INTRODUÇÃO E OBJETIVO: Realizar análise morfométrica das fibras mielínicas dos nervos laríngeos com a finalidade de verificar modificações quantitativas decorrentes do processo de envelhecimento. FORMA DE ESTUDO: Clínico e experimental. Material e Método: Foi coletado fragmento de 1cm dos nervos laríngeos superiores e nervos laríngeos recorrentes de 12 cadáveres do sexo masculino. A amostra foi dividida em dois grupos: idade inferior a 60 anos (Adulto) e idade igual ou superior a 60 anos (Idoso). O material foi avaliado em microscópio de luz acoplado a sistema analisador de imagem. RESULTADOS: O número total de fibras mielínicas do nervo laríngeo superior foi semelhante nos dois grupos etários, mas com tendência para o maior número de fibras de 1µm no grupo adulto (p=0,0744). O grupo adulto apresentou maior número total de fibras mielínicas no nervo laríngeo recorrente (p=0,0006), e esta diferença ocorreu nas fibras com diâmetros de 1-3µm (p<0,007). O grupo adulto apresentou maior número total de fibras mielínicas nos nervos laríngeos (soma das fibras dos nervos laríngeos superiores e dos nervos laríngeos recorrentes) que o grupo idoso (p<0,0091). CONCLUSÃO: O número total de fibras mielínicas dos nervos laríngeos é maior no grupo com idade inferior a 60 anos.

INTRODUCTION AND AIM: To carry out a morphometric analysis of myelinic fibers in laryngeal nerves aiming to identify quantitative changes as a result of aging. Study design: Clinical and experimental. MATERIAL AND METHOD: A 1cm fragment was collected from the superior laryngeal nerves and recurrent laryngeal nerves taken from twelve male cadavers. The sample was divided into two groups: those aged below 60 years (Adult) and those aged 60 years or more (Elderly). The material was evaluated under light microscopy coupled with an image analysis system. RESULTS: The total number of myelinic fibers from the superior laryngeal nerve was similar in both age groups; there was, however, a trend for a higher number of 1ìm fibers in the adult group (p=0.0744). The adult group had a higher total number of myelinic fibers in the recurrent laryngeal nerve (p=0.0006), and this difference was seen in fibers with diameters betwee 1-3ìm (p<0.007). The adult group had a higher total number of myelinic fibers in the laryngeal nerves (sum of superior laryngeal nerves and recurrent laryngeal nerves fibers) compared to the elderly group (p<0.0091). CONCLUSION:The total number of myelinic fibers in laryngeal nerves is higher for the group aged below 60 years.

Protocolo anatômico-cirúrgico das relações entre os nervos laríngeos recorrentes e as artérias tireóideas inferiores: estudo em 79 tireoidectomias / Anatomical-surgical protocol of the relation between recurrent laringeal nerves and inferior thyroidal artery in 79 thyroidectomies

INTRODUÇÃO: Os cuidados com as preservações dos nervos laríngeos recorrentes e das glândulas paratireóides, nas tireoidectomias, continuam desafiando os cirurgiões em razão das graves complicações que podem ocorrer quando são manipulados inadequadamente. O trabalho teve como objetivo, no curso das tireoidectomias totais e parciais, estabelecer protocolo anatômico-cirúrgico das relações anatômicas entre os nervos laríngeos recorrentes com as artérias tireóideas inferiores, identificar-preservar esses nervos e as glândulas partireóides. MÉTODO: Os registros fotográficos durante os trans-operatórios foram obtidos de 79 pacientes submetidos às tireoidectomias totais e parciais (lobectomia total direita ou esquerda e istmectomia), respectivamente, com as identificações dos nervos e artérias bi ou unilateralmente, propondo expor as relações anatômicas entre essas estruturas, operados entre janeiro de 2005 e julho de 2006. RESULTADOS: Os registros fotográficos foram adaptados aos desenhos esquemáticos para estabelecer os principais pontos de referências anatômicas dos nervos laríngeos recorrentes em relação às artérias tireóideas inferiores, totalizando 116 nervos laríngeos recorrentes. CONCLUSÃO: A íntima relação dos nervos laríngeos recorrentes e as artérias tireóideas inferiores podem se apresentar de diversas formas, incluindo as anomalias congênitas, como a do laríngeo não recorrente, as duplicações e triplicações pré-laríngeas do nervo, sem dúvida, algumas vezes, dificultando a identificação dessas estruturas. São imperativas as claras identificações dessas estruturas e das glândulas paratireóides para preservá-las, no curso das tireoidectomias totais e parciais, a fim de evitar as complicações pós-operatórias.

BACKGROUND: Care in preserving the recurrent laryngeal nerves and the parathyroids glands, during thyroidectomies, continue to challenge surgeons because of the serious complications, which can occur when they are inadequately handled. The work aimed at establishing a surgical-anatomical protocol of the relations between the recurrent laryngeal nerves with the lower thyroidal arteries and identify and preserve the nerves and the parathyroids glands, in the course of total and partial thyroidectomies. METHODS: The photographic records during the surgery have been obtained from 79 patients who were submitted to total and partial thyroidectomies (total right or left lobectomy and istmectomy) respectively, with identification of the nerves and arteries, both unilateral and bilateral, proposing to expose the anatomical relations between these structures, operated on between January 2005 and July 2006. RESULTS: The photographic records were adapted to the schematic drawings so as to establish the major anatomical points of reference of the recurrent laryngeal nerves vis-à-vis the inferior thyroidal arteries were completed in a total of 116 recurrent laryngeal nerves. CONCLUSION: The intrinsic relation of the nerves with the arteries can occur in different forms, including the congenital abnormalities, as that of the non-recurrent laryngeal, the prelaryngeal duplications and triplications of the nerve, undoubtedly hindering the identification of such structures. Even under the protection of the anatomic and surgical difficulties, a clear identification of the nerve, artery and the parathyroid glands is imperative to preserve them in the course of total and partial thyroidectomies in order to avoid post-surgical complications.

Intraoperative Study of 1988 Recurrent Laryngeal Nerves / 昆明医科大学学报

Objective To study the anatomical relationship between the recurrent laryngeal nerve(RLN)and the inferior thyroid artery,to investigate the prophylactic measures on how to avoid iatrogenic injures while exposing the RLN during thyroid operation.Methods Retrospectively reviewed the clinical data of 1 345 patients accepted thyroid operation with RLN exposing.Results A total of RLN 1 988 were observed,874 on the left and 1 114 on the right(including 2 non-recurrent laryngeal nerve).On the left side,the nerve passed anterior to the artery in 32.8%,posterior to it in 26.7%,and between the branches of the artery in 41.6%.On the left side,the nerve was found coursing anterior to the artery in 36.2%,posterior to it in 28.2%,and between the branches in 35.3%.6 nerves were iatrogenic injured,4 cases were temporary injured and 2 were permanent.Conclusions Although the anatomical relationship between the RLN and the inferior thyroid artery are variable,iatrogenic injures of the nerve can be avoid by exposing it,and an experienced surgeon with good knowledge of RLN anatomical characteristics and skilled surgical techniques was needed.

Respiratory Difficulty at a Postanesthesia Care Unit after Total Thyroidectomy: A case report / 대한마취과학회지

We had a case of respiratory difficulty following total thyroidectomy due to bilateral vocal cord palsy. The patient was a 49-year-old female undergoing total thyroidectomy for papillary carcinoma of the thyroid. Anesthesia was performed uneventfully. Spontaneous respiration resumed after reversal of the neuromuscular blockade. However, after arriving at the postanesthesia care unit, she developed hypertension, anxiety, tachypnea, and inspiratory stridor during deep inspiration. Because the patient maintained adequate oxygen saturation, we confirmed bilateral vocal cord palsy by fiberoptic laryngoscopy. During the operation, the surgeon experienced difficulty dissecting the bilateral recurrent laryngeal nerves from the surrounded tumor. So we consider that direct nerve injury was responsible for the bilateral vocal cord palsy. Movement of the right vocal cord recovered a week later.

Respiratory Difficulty at a Postanesthesia Care Unit after Total Thyroidectomy: A case report / 대한마취과학회지

We had a case of respiratory difficulty following total thyroidectomy due to bilateral vocal cord palsy. The patient was a 49-year-old female undergoing total thyroidectomy for papillary carcinoma of the thyroid. Anesthesia was performed uneventfully. Spontaneous respiration resumed after reversal of the neuromuscular blockade. However, after arriving at the postanesthesia care unit, she developed hypertension, anxiety, tachypnea, and inspiratory stridor during deep inspiration. Because the patient maintained adequate oxygen saturation, we confirmed bilateral vocal cord palsy by fiberoptic laryngoscopy. During the operation, the surgeon experienced difficulty dissecting the bilateral recurrent laryngeal nerves from the surrounded tumor. So we consider that direct nerve injury was responsible for the bilateral vocal cord palsy. Movement of the right vocal cord recovered a week later.

Comparative analysis of early and mid-stage nerve decompression and nerve anastomosis for traumatic recurrent laryngeal nerve injuries / 中华创伤杂志

Objectives To explore therapeutic effect,indication and timing of nerve decompression for traumatic recurrent laryngeal nerve injury inducing vocal cord paralysis. Methods A total of 42 patients with recurrent laryngeal nerve injury inducing vocal cord paralysis within six months, were divided into nerve decompression group (15 cases), end to end anastomosis of recurrent laryngeal nerve group (six cases) and nonsurgical treatment (21 cases). Nerve decompression was performed in the patients who were operatively found to have compressing sutures or compression due to cicatricial hypertrophy. Results In 13 patients with a course less than four months, nerve decompression restored normal functional adductory and abductory motion of the vocal cord in 11 patients and motionless in two. Although functional motion of vocal cord was not seen in two patients with a course less than four months and two longer than four months, the mass and tension of the reinnervated vocal cord became much the same as the contralateral normal vocal cord, thus resuming symmetric vibration of the vocal cords and physiological phonation. End-to-end anastomosis of recurrent laryngeal nerve failed to restore motion of the glottis. Nevertheless, the procedures enabled adductory muscles to be reinnervated and then restored normal voice. Although nonsurgical treatment improved severe hoarseness, the vocal cord didn't restore normal functional motion of the vocal cord and normal voice. Conclusions Early and mid-stage recurrent laryngeal nerve decompression may restore normal motion of the vocal cord. End-to-end anastomosis of recurrent laryngeal nerve enables adductory muscles to be reinnervated and thus restores normal voice.

Expression and distribution of ciliary neurotrophic factor in peripheral nerve degeneration and regeneration / 第二军医大学学报

Objective:To explore the expression and distribution of ciliary neurotrophic factor (CNTF) in laryngeal nerve degeneration and regeneration. Methods:Transection of the recurrent laryngeal nerves in 8 dogs and suture following transection in 12 cases were performed. Both proximal and distal ends of transected or sutured region were sectioned at various survival times for CNTF immunohistochemistry and CNTF mRNA in situ hybridization. The area and intensity of reactive product were measured by computer image processing system. Results:After nerve transection, reactive product of CNTF mRNA and its protein reduced rapidly in distal stumps, after neurorrhaphy, they were observed in thin Schwann cell processes ensheathing axons and not found in the proliferating Schwann cells which didn′t ensheathe axons. CNTF immunoreactivity was also detected in the regenerated nerve axons. CNTF expression increased with survival time, but even at the longest survival time, it was still significantly less than that in intact nerve. The same change was observed in a short segment proximal to the transected or sutured region. Conclusion:CNTF expression is in the down regulation and is collected with Schwann cell axon in peripheral nerve degeneration and regeneration. The changed distribution of CNFT might provide a supportive environment for axonal regeneration.

Experimental Study on Excitability of Thyroarytenoid Muscle after Reinnervation / 第二军医大学学报

The recurrent laryngeal nerves of 16 dogs were sectioned to paralyze the vocal cord on the left side. The ansa hypoglossi nerve was cut on the same side, its proximal end was implanted into the thyroarytenoid (TA) muscle belly on the left side in six animals. It was anastomosed with the adductor branch of the recurrent larygeal nerve on the left side in five animals and the other five didn't receive reinnervated operations. After a period of five to six months, the operated areas were reexplored. The excitability values of the implanted nerve, anastomosed proximal and distal nerves, right recurrent laryngeal nerve, normal TA muscle, reinnervated TA muscle and denervated TA muscle were tested respectively in 16 dogs. The results indicated that the excitability values of the implanted and anastomosed nerves were equivalent to those of the normal nerves and were significantly higher than those of the reinnervated muscle which were equivalent to those of the normal muscle. The excitability values of the denervated TA muscles were lowest.