RESUMEN

PURPOSE: The aim of this systematic review and meta-analysis was to systematically review and perform a meta-analysis on the anatomical variations of the RLN. METHODS: We performed online research for studies that addressed anatomical variations of the RLN and laterality, published between 2015 and 2021. We found 230 articles, and nine were included. RESULTS: Eight variations were found, with Type I prevailing (41.17%; 95% CI 19.44-64.88), extra laryngeal divergence of the RLN. The other types were: II-fan shape; III-distance greater than 5 mm to the cricothyroid joint; IV-thickening and adipopexy in the elderly; V-non-recurrent laryngeal nerve; VI-intracranial branch; VII-tortuous ascending RLN; and VIII-combination between the inferior branch of the NV and the ascending trunk of the RLN. Types I (p = 0) and III (p < 0.01) prevailed on the left and types II (p < 0.01) and V (p < 0.01) on the right. CONCLUSIONS: It was observed that variations occurred due to the path of the RLN to the entrance to the larynx, its shape, and the age of the evaluated individual. The most frequent variation and side were, respectively, Type I, extra laryngeal divergence and left.

Asunto(s)

RESUMEN

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.

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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

PURPOSE: To describe the anatomical course of the intralaryngeal portion of the inferior laryngeal nerve (ILN) and to standardize the surgical access to its thyroarytenoid branch (TAb) through the thyroid cartilage. METHODS: Under surgical microscopy, 33 adult human excised larynges were dissected, to expose the intralaryngeal portion of ILN. The point of entry of TAb, ILN's terminal branch, in the thyroarytenoid (TA) muscle was determined and correlated with thyroid cartilage dimensions. RESULTS: After entering the larynx, the ILN consistently traveled between the thyroid cartilage and the lateral cricoarytenoid muscle in an anterior and slightly cranial course. The distance from the point of entry of the TAb in the TA muscle to the midline (TAb-H) and to the inferior border (TAb-V) of the thyroid cartilage differed according to gender. In females, mean distances of TAb-H and TAb-V were 20.5mm and 5.2mm and in males, 22.3mm and 5.9mm, respectively. CONCLUSION: The intralaryngeal course of the inferior laryngeal nerve presents low variability and measures from landmarks in the thyroid cartilage help to estimate the point of entry of thyroarytenoid branch in thyroarytenoid muscle.

Asunto(s)

RESUMEN

ABSTRACT PURPOSE: To describe the anatomical course of the intralaryngeal portion of the inferior laryngeal nerve (ILN) and to standardize the surgical access to its thyroarytenoid branch (TAb) through the thyroid cartilage. METHODS: Under surgical microscopy, 33 adult human excised larynges were dissected, to expose the intralaryngeal portion of ILN. The point of entry of TAb, ILN's terminal branch, in the thyroarytenoid (TA) muscle was determined and correlated with thyroid cartilage dimensions. RESULTS: After entering the larynx, the ILN consistently traveled between the thyroid cartilage and the lateral cricoarytenoid muscle in an anterior and slightly cranial course. The distance from the point of entry of the TAb in the TA muscle to the midline (TAb-H) and to the inferior border (TAb-V) of the thyroid cartilage differed according to gender. In females, mean distances of TAb-H and TAb-V were 20.5mm and 5.2mm and in males, 22.3mm and 5.9mm, respectively. CONCLUSION: The intralaryngeal course of the inferior laryngeal nerve presents low variability and measures from landmarks in the thyroid cartilage help to estimate the point of entry of thyroarytenoid branch in thyroarytenoid muscle.

Asunto(s)

RESUMEN

The recurrent laryngeal nerve has been reported to supply cardiac branches to the cardiac plexus. A review of anatomical literature on the existing term used to describe these branches revealed that varying interpretations and descriptions exist among various authors. Therefore, this study aimed to investigate the origin and incidence of branches from the recurrent laryngeal nerves to the cardiac plexus and their connections with sympathetic cardiac nerves. The sample comprised 40 cadaveric fetuses (n=80) (gestational ages: 16-30 weeks). The recurrent laryngeal cardiac nerve was described as the cardiac branch that originated directly from the recurrent laryngeal nerve and reached the superficial or deep parts of the cardiac plexus. This study found the recurrent laryngeal cardiac nerve in 76% of the cases contributing direct and indirect branches in 75% and 25% of the cases, respectively. This study recorded only two (2%) of these branches contributing to the superficial cardiac plexus while the rest (74%) of these branches contributed to the deep cardiac plexuses. The remaining 24% had no contributions from the recurrent laryngeal nerve to either the superficial or deep part of the cardiac plexus. The most common point of origin for the recurrent laryngeal cardiac nerve was at the lower distal part in 59% of the specimens. In the remaining 41% of branches, this nerve originated from the point of curvature, upper proximal part and both the point of curvature and lower distal part in 26%, 10% and 5% of the specimens.

El nervio laríngeo recurrente suministra las ramas cardiacas para el plexo cardíaco. Una revisión de la literatura anatómica nos muestra que existen diferentes interpretaciones y descripciones de estas ramas por parte de los distintos autores consultados. En consecuencia este estudio tuvo como objetivo investigar el origen, además de la incidencia de las ramas de los nervios laríngeos recurrentes al plexo cardíaco y sus conexiones con los nervios cardiacos simpáticos. La muestra incluyó 40 fetos (n=80) (edades gestacionales: 16-30 semanas). El nervio laríngeo recurrente cardiaco fue descrito como la rama cardíaca que se originó directamente del nervio laríngeo recurrente, que llega a las partes superficiales o profundas del plexo cardíaco. En este estudio observamos que el nervio laríngeo recurrente cardiaco en el 76% de los casos contribuye a las ramas directas e indirectas, en el 75% y el 25% de los casos, respectivamente. Se observó en este estudio que solamente dos (2%) de estas ramas contribuían en la formación del plexo cardíaco superficial, mientras que el resto (74%) de estas ramas contribuía a los plexos cardíacos profundos. El 24% restante no tenía contribuciones del nervio laríngeo recurrente ya sea para la parte superficial o profunda del plexo cardíaco. El punto de origen más común del nervio laríngeo recurrente cardiaco se observó en la parte distal inferior en un 59% de las muestras. En el 41% restante de las ramas este nervio se originó desde el punto de curvatura, la parte proximal superior y tanto en el punto de curvatura inferior como la parte distal en 26%, 10% y 5% de los especímenes.

Asunto(s)

RESUMEN

This study investigated the sexual dimorphism in the recurrent laryngeal nerve (RLN) and thyroarytenoid (TA) muscle, which control the vocal fold. The RLN and TA were bilaterally studied in human specimens obtained from necropsies (seven men and seven women). Analysis of the morphometric parameters showed that the RLN of the men were significantly larger, as shown by the intraperineural area (42.5%) (P=0.006), total number of fibers (38.0%) (P=0.0002), axonal area (34.3%) (P=0.0001), axonal diameter (19.0%) (P=0.0001), and the area of the nerve occupied by myelinated fibers (34.9%) (P=0.001). By contrast, in women, our results showed that the area of the RLN occupied by endoneurial connective tissue was larger (5.7%) (P=0.001). Estimation of the fiber area and shape coefficient showed that the histologic organization of TA is similar in men and women. These results may contribute toward enhancing our understanding about the voice neurobiology.

Asunto(s)

RESUMEN

OBJECTIVE: To study the anatomical relations of the recurrent laryngeal nerve (RLN) with the ligament of Berry (LB), and point out the different ways of presenting the relationship between these two structures. METHODS: We conducted a study with anterior cervical dissection of 22 corpses, in the years 2009 and 2010, with attention towards the frequency of presentation of anatomical relations between the NLR and Berry ligament, with the following classification: Type I or intraligamentary: the nerve and / or its branches were visualized in the ligament substance conjunctiva; Type IIA or lateral: nerve and / or its branches lateral to the ligament; Type IIB or lateral paraligamentary: nerve and / or its side branches and in contact with the ligament without penetrating it; Type III or medial: nerve and / or its branches visualized after complete dissection of the ligament, in lateral-medial position. RESULTS: The study analyzed 41 RLNs, which comprised eight (19.5%) of type I, 20 (48.8%) Type II, five (12.2%) Type IIB and eight (19.5%) type III. Of the 19 (86.3%) RLNs dissected bilaterally in the same cadaver, 11 (57.8%) displayed a classification in one side of the neck different from the one of the other side. CONCLUSION: Due to its proximity to the RLN and the anatomical variability, the Berry ligament should not be considered a reliable parameter for repair and preservation of the recurrent laryngeal nerve. Hence, the indiscriminate latero-medial dissection of the ligament is not recommended without direct visualization of the nerve.

Asunto(s)

RESUMEN

OBJETIVO: Estudar as relações anatômicas do nervo laríngeo recorrente (NLR) com o ligamento de Berry (LB), e assinalar as diferentes formas de apresentação das relações entre essas duas estruturas. MÉTODOS: Estudo realizado a partir da dissecção cervical anterior de 22 cadáveres, nos anos de 2009 e 2010, com estabelecimento das frequências de apresentações anatômicas das relações entre o NLR e o ligamento de Berry, na seguinte categorização: Tipo I ou intraligamentar: o nervo e/ou seus ramos eram visualizados na substância conjuntiva do ligamento; Tipo IIA ou lateral: nervo e/ou seus ramos apresentavam-se laterais ao ligamento; Tipo IIB ou lateral justaligamentar: nervo e/ou seus ramos estavam laterais e em contato com o ligamento, sem penetrá-lo; Tipo III ou medial: nervo e/ou seus ramos eram visualizados após a dissecção completa do ligamento em direção látero-medial. RESULTADOS: O estudo analisou 41 NLR, sendo: oito (19,5%) do Tipo I; 20 (48,8%) do Tipo IIA; cinco (12,2%) Tipo IIB e oito (19,5%) do Tipo III. Dos 19 (86,3%) NLR dissecados bilateralmente no mesmo cadáver, 11 (57,8%) eram discordantes em relação ao outro lado do pescoço quanto à classificação. CONCLUSÃO: Pela sua proximidade com o NLR e pelas variáveis anatômicas dessa topografia, o ligamento de Berry não deve ser considerado um parâmetro seguro para reparo e preservação do nervo laríngeo recorrente, não sendo recomendada a dissecção indiscriminada látero-medial do ligamento, sem a visualização direta do nervo.

OBJECTIVE: To study the anatomical relations of the recurrent laryngeal nerve (RLN) with the ligament of Berry (LB), and point out the different ways of presenting the relationship between these two structures. METHODS: We conducted a study with anterior cervical dissection of 22 corpses, in the years 2009 and 2010, with attention towards the frequency of presentation of anatomical relations between the NLR and Berry ligament, with the following classification: Type I or intraligamentary: the nerve and / or its branches were visualized in the ligament substance conjunctiva; Type IIA or lateral: nerve and / or its branches lateral to the ligament; Type IIB or lateral paraligamentary: nerve and / or its side branches and in contact with the ligament without penetrating it; Type III or medial: nerve and / or its branches visualized after complete dissection of the ligament, in lateral-medial position. RESULTS: The study analyzed 41 RLNs, which comprised eight (19.5%) of type I, 20 (48.8%) Type II, five (12.2%) Type IIB and eight (19.5%) type III. Of the 19 (86.3%) RLNs dissected bilaterally in the same cadaver, 11 (57.8%) displayed a classification in one side of the neck different from the one of the other side. CONCLUSION: Due to its proximity to the RLN and the anatomical variability, the Berry ligament should not be considered a reliable parameter for repair and preservation of the recurrent laryngeal nerve. Hence, the indiscriminate latero-medial dissection of the ligament is not recommended without direct visualization of the nerve.

Asunto(s)

RESUMEN

One of the most exciting questions about the human voice is how the vocal fold produces and modulates different sounds. One hypothesis to explain the wide range of movements found in the vocal fold is based on the variety of muscle fiber orientations in the thyroarytenoid (TA) muscle. The tongue (TO) muscle is considered the most complex structure in the body in terms of muscle fiber orientation and movements. Thus, possible similarities between these two muscles and their innervations, the recurrent laryngeal nerve (RLN) and hypoglossal nerve (XII), could explain the complex movements executed by the focal fold. Moreover, such studies help us to understand some microanatomical aspects of vocal fold reinnervation, based on XII-to-RLN anastomosis. Therefore, this study investigates the histological organization of TA and TO muscles and their innervations (n=12 subjects). The muscle fibers were classified into three categories according to their orientation (transverse, undefined, and longitudinal). To quantify the percentage of fibers in each category in the TA and TO, the shape coefficient (shape Z) was estimated. Qualitative analysis and estimation of fiber area and shape Z show that the histological organization of TA and TO muscle is similar. Both muscles present the same percentage of transversal (~72%), undefined (~15%), and longitudinal fibers (~10%). By contrast, the authors' analysis of the morphometric parameters of the RLN and XII shows that there is no correlation between these nerves. In conclusion, in humans, TA and TO muscles present similar histological organization and this finding could help to explain interesting questions about human phonation.

Asunto(s)

RESUMEN

Parathyroid glands play an important role in controlling calcium levels, which influence muscular contraction and neurotransmission. The number of variants, localization and ectopic positions make these glands tricky during surgical exploration. Detailed anatomical knowledge of these glands is fundamental to avoid postsurgical hypoparathyroidism, such as failures during thyroidectomy and parathyroid procedures. The purposes of this work were to study and report practical knowledge for surgeons in order to localize the glands. Dissections were performed on 56 cadavers. Gland identity was confirmed by histological study. Also, mediastinal tissue and the carotid sheath were treated with Carnoy's solution to identify ectopic glands. The thyroid gland was divided and sliced to identify parathyroid glands in the parenchymal and subcapsular space. Four or more parathyroid glands were found in 89.3% of the studied specimens. Mean gland weight was 33.1 mg, and its mean measurements were 6.7 × 3.9 × 2.0 mm. In more than 90% of the cases there was a correlation with the inferior laryngeal nerve and the parathyroid glands: the upper glands were located in medial positions, and the lower ones were found to be located laterally. In 42.8% of cases at least one ectopic gland was observed. The main ectopic regions were the mediastinum and thymus (19.6%), thyroid subcapsular space (12.5%) and thyroid parenchyma (5.4%). Quantity, gland characteristics and location were not influenced by anthropometric and demographic parameters. Here we show the high incidence of parathyroid glands positioned at "abnormal" locations, and as a controversial topic in endocrine surgery, this matter must be continuously studied and reported in the literature.

Asunto(s)

RESUMEN

Histological studies of the human recurrent laryngeal nerves (RLNs) have described differences in fiber length and thickness between the right and left RLNs. This asymmetry is probably involved in the different times of arrival of the stimuli to the laryngeal musculature controlled by each nerve. Histological and structural differences between the right and left RLNs could explain the synchronicity of laryngeal musculature contraction despite the differing nerve lengths. The purpose of this investigation was to shed some light on this paradigm by obtaining estimates of some morphometric parameters, such as intraperineural area, intraperineural perimeter, fiber area, fiber perimeter, fiber density (number of fibers/mm(2)), and total number of fibers in the right and left RLN of humans. Thus, the right and left RLNs were studied in a total sample of eight human specimens obtained from necropsies. The nerves were analyzed using histology, and the morphometric parameters were measured using Image Pro Plus Software 4.1 (Media Cybernetics, Silver Spring, MD, USA). No statistical differences between the two RLNs were observed in the intraperineural area, intraperineural perimeter, density (number of fibers/mm(2)), and total number of fibers. However, the area and perimeter of fibers of the right RLN were statistically larger when compared with those of the left RLN--21% and 11%, respectively. In conclusion, we show that in humans, the area and perimeter of the right RLN are larger than those of the left RLN. This morphological finding is probably related to the different time of arrival of the stimulus to the laryngeal musculature.

Asunto(s)

RESUMEN

OBJECTIVES: To analyze the frequency of extralaryngeal branching (ELB) of the recurrent laryngeal nerve (RLN) in a consecutive series of patients undergoing thyroidectomy by the same group of surgeons during an extended period and to compare our findings with the data available in the literature. DESIGN: Retrospective medical record study. SETTING: Academic research. PATIENTS: From March 1, 1983, to September 30, 2008, 2677 patients underwent thyroidectomy. Of these, 1638 patients had surgical information about at least 1 RLN. A total of 1081 patients underwent bilateral operations. During the last 5 years of the study, intraoperative laryngeal nerve monitoring was performed in selected patients using a commercially available system. MAIN OUTCOME MEASURES: Information was obtained regarding 2154 RLNs. RESULTS: A total of 1390 RLNs (64.53%) had ELB. Among 447 patients in whom intraoperative laryngeal nerve monitoring was used, the anterior branches usually exhibited more electrophysiologic activity. CONCLUSIONS: Extralaryngeal branching was found in 64.53% of RLNs in this case series. In recent patients with intraoperative laryngeal nerve monitoring, electrophysiologic activity was observed in the branches, particularly the anteriorly situated ones. Recognition of this frequent anatomical configuration and meticulous preservation of all branches are of paramount importance to decrease postoperative morbidity associated with thyroidectomy.

Asunto(s)

RESUMEN

Studies on the normal pattern of development and post-natal maturation of the recurrent laryngeal nerve in rats are scanty. The aim of the present study was to investigate the normal microscopic aspects of the recurrent laryngeal nerve myelinated fibers in the post-natal developing rat, with special attention to longitudinal morphology and lateral symmetry. Fifteen male rats were divided into experimental groups according to age 20, 55, 76, 150 and 250 days. A female group aged between 76 and 150 days was also used. Right and left RLN were studied by light microscopy at proximal, medium and distal segments and morphometric data comparisons were made between sides, segments, ages and gender. Our results showed that the left recurrent laryngeal nerves were significantly longer than the right in all ages studied and this difference increased with ageing. There was a slight decrease in the myelinated fiber number, according to proximal to distal gradient, but a significant decrease was observed only on older animals (ages 55 (both sides), 76 (left side), and 150 (left side) days). This difference was also observed for female rats (left side). No differences between ages were observed. There was an age-dependent difference on ranges and histograms form (younger animals showed a unimodal histogram while older animals showed a bimodal one), with no significant differences between segments or sides, in all groups studied. Also, no differences between males and females of the same age were observed. In conclusion, the RLN alters its morphology due to development and ageing and the present study describe normal patterns of the recurrent laryngeal nerve development in rats that can be useful for a better understanding of pathological alterations on experimental neuropathies involving the laryngeal nerves.

Asunto(s)

RESUMEN

Objetivo: O objetivo foi realizar análise morfométrica das fibras mielínicas dos nervos laríngeos e do nervo hipoglosso direito com a finalidade de verificar modificações quantitativas decorrentes do processo de envelhecimento. Método: Foi coletado fragmento de 1 cm do nervo laríngeo superior (lados direito e esquerdo), nervo laríngeo recorrente (lados direito e esquerdo) e nervo hipoglosso do lado direito de 12 cadáveres do sexo masculino, sem antecedentes para doenças como: diabetes, alcoolismo, e neoplasia maligna. A amostra foi dividida em dois grupos: grupo com idade inferior a 60 anos, composto por seis cadáveres; grupo com idade igual ou superior a 60 anos, composto por seis cadáveres. O material foi fixado em solução de glutaraldeído 2,5 por cento e paraformaldeído 2 por cento; pós-fixado em tetróxido de ósmio; desidratado em concentrações crescentes de etanol e incluído em resina epóxi. Os blocos foram cortados em ultramicrótomo com navalhas de vidro, para obtenção de cortes semifinos de 0,3 μm de espessura, que foram colocados em lâmina de vidro, corados com azul de toluidina a 1 por cento e avaliados em microscópio de luz acoplado a sistema analisador de imagens. Os seguintes dados morfométricos foram quantificados: área de secção transversal intraperineural, número e o diâmetro das fibras mielínicas. Resultados: Para todos os parâmetros avaliados dos nervos laríngeos (área intraperineural, densidade de fibras mielínicas por mm2 e número total de fibras), não houve diferença entre os lados direito e esquerdo, nos dois grupos etários. A área intraperineural dos nervos laríngeos foi semelhante nos dois grupos etários; entretanto, a área intraperineural dos nervos laríngeos superiores foi maior que dos nervos laríngeos recorrentes (p<0,0001). O número total de fibras mielínicas do nervo laríngeo superior foi semelhante nos dois grupos etários (p=0,1188), mas com tendência para o maior número de fibras de 1 μm no grupo com idade inferior a 60 anos (p=0,0744). O grupo com idade inferior a 60 anos apresentou maior número total de fibras mielínicas no nervo laríngeo recorrente que o grupo idoso (p=0,0006), e esta diferença ocorreu nas fibras mielínicas com diâmetros de 1, 2 e 3 μm (p<0,007)...

Asunto(s)

RESUMEN

Objetivo: o objetivo foi realizar análise morfométrica das fibras mielínicas dos nervos laríngeos e do nervo hipoglosso direito, em 2 grupos etários distintos, com a finalidade de verificar modificações quantitativas decorrentes do processo de envelhecimento. Método: foi coletado fragmento de 1 cm do nervo laríngeo superior (lados direito e esquerdo), nervo laríngeo recorrente (lados direito e esquerdo) e nervo hipoglosso do lado direito de 12 cadáveres do sexo masculino, sem antecedentes para doenças como: diabetes, alcoolismo, e neoplasia maligna. A amostra foi dividida em 2 grupos: grupo com idade inferior a 60 anos, composto por 6 cadáveres; grupo com idade igual ou superior a 60 anos, composto por 6 cadáveres. O material foi fixado em solução de glutaraldeído 2,5% e paraformaldeído 2%; pós-fixado em tetróxido de ósmio; desidratado em concentrações crescentes de etanol e incluído em resina epóxi. Os blocos foram cortados em ultramicrótomo com navalhas de vidro, para obtenção de cortes semifinos de 0,3 µm de espessura, que foram colocados em Lãmina de vidro, corados com azul de toluídina a 1% e avaliados em microscópio de luz acoplado a sistema analisador de imagens. Os seguintes dados morfométricos foram quantificados: área de secção transversal intraperineural, número e o diâmetro das fibras mielínicas. Conclusões: o número total de fibras mielínicas do nervo laríngeo recorrente é maior no grupo com idade inferior a 60 anos, e esta diferença ocorre nas fibras mielínicas de 1 μm a 3 μm de diâmetro. O grupo com idade inferior a 60 anos apresenta maior número total de fibras mielínicas nos nervos laríngeos. O número total de fibras mielínicas do nervo hipoglosso direito è semelhante nos dois grupos etários

Asunto(s)

RESUMEN

OBJETIVO: Descrever a anatomia do nervo laríngeo recorrente (NLR) bilateralmente, correlacionando-a com os prováveis mecanismos de lesão na abordagem cervical anterior. MÉTODO: Foram examinados 12 cadáveres de adultos provenientes do Laboratório de Microcirurgia da Faculdade de Medicina da UFMG. Os dados foram analisados em termos de freqüência, média e desvio-padrão. RESULTADOS: O NLR esquerdo teve comprimento total médio de 9,4 ± 1,6 cm. Penetra na laringe em 36,3 por cento dos casos na altura de C5, 18,2 por cento de C4, 18,2 por cento de C5-C6, 18,2 por cento de C6 e 9,1 por cento de C4-C5. Recorre em 45,4 por cento dos casos na altura de T3, 18,2 por cento de T3-T4, 18,2 por cento de T4 e 18,2 por cento de T5. O NLR direito teve comprimento total médio de 5 ± 0,3 cm. Penetra na laringe em 44,4 por cento dos casos na altura de C5, em 44,4 por cento de C6 e 11,1 por cento de C3-C4. Recorre em 60 por cento dos casos na altura de T1, 30 por cento de C7 e 10 por cento de T2. CONCLUSAO: O NLR direito encontra-se mais vulnerável a lesões operatórias por dois aspectos diferentes e complementares: trajetória e comprimento. Devido ao fato de apresentar trajetória mais oblíqua e desprotegida, não se relacionando de forma íntima com o sulco traqueoesofágico, existe maior possibilidade de ocorrerem traumas diretos, como a compressão por retratores ou a secção acidental, principalmente nas abordagens envolvendo níveis vertebrais mais baixos. Da mesma forma, o seu menor comprimento favorece o estiramento de suas fibras durante a tração per-operatória.

Asunto(s)

RESUMEN

OBJECTIVE: To present an anatomical description of the recurrent laryngeal nerve (RLN) on both sides of the larynx as it relates to the possible lesion mechanisms in anterior cervical spine surgery. METHOD: Twelve adult cadavers were examined from the microsurgical laboratory at the School of Medicine at UFMG, MG, Brazil. The data collected were analyzed in terms of frequency, average and standard deviation. RESULTS: The left RLN had a total average length of 9.4 +/- 1.6 cm entering the larynx in 36.3% of the cases at the approximate height of C5, 18.2% at C4, 18.2% at C5-C6, 18.2% at C6 and 9.1% at C4-C5. Recurrence appeared in 45.4% of the cases at the approximate height of T3, 18.2% at T3-T4, 18.2% at T4 and 18.2% at T5. The right RLN had a total average length of 5 +/- 0.3 cm entering the larynx in 44.4% of the cases at the approximate height of C5, 44.4% at C6, and 11.1% at C3-C4. Recurrence appeared in 60% of the cases at the approximate height of T1, 30% at C7 and 10% at T2. CONCLUSION: The right RLN was found to be more vulnerable to operational lesions due to two complimentary yet different reasons, trajectory and length. Owing to the fact that a more oblique and unprotected trajectory is not related directly with the tracheoesphageal groove, there is a strong possibility of direct traumas occurring as with the resulting compression from the employ of surgical retractors or an accidental cut, principally in surgeries involving lower vertebral levels. In the same way, the smallest RNL length favors the stretching of fibers during the per-operative traction.

Asunto(s)

RESUMEN

An anatomical study of 50 fresh adult human cadavers was performed in order to verify prevalence of Galen's anastomosis (GA) and to evaluate whether factors such as gender, ethnicity, side of the neck, and individual stature may interfere with GA prevalence. The results were analysed using the Chi-square test, Student t-test, and F-Snedecor test. GA was observed in 87 of 100 dissections. There was no statistically significant difference regarding GA prevalence between groups separated by ethnicity (p = 0.853), gender (p = 0.198), side of the neck (p = 0.766), or individual height (p = 0.199). Therefore, the GA was a frequent anatomical finding, and this result was not influenced by any studied factor. Comparing our data with previous studies, we also concluded that the GA seems to play an important role in the innervation of the larynx, even though its function remains unclear. Also, it is reasonable to consider GA a constant anatomical constituent.

Asunto(s)

RESUMEN

The anatomical relationship between the recurrent laryngeal nerve (RLN) and the inferior thyroid artery (ITA) was studied in 76 embalmed corpses, 8 females and 68 males. In both sexes, the RLN lay more frequently between branches of the ITA.; it was found in this position in 47.3 percent of male corpses and 42.8 percent of female ones. On the right, RLN was found between branches of the ITA in 49.3 percent of the cases, anterior to it in 38.04 percent, and posterior in 11.26 percent. On the left, the RLN lay between branches of the ITA in 44.45 percent, posterior to the ITA in 37.05 percent, and anterior to it in 18.05 percent of the cases. In 62.68 percent of the cases, the relationship found on one side did not occur again on the opposite side. There was a significant difference (p<0.05) in the distribution of the 3 types of relationships between the RLN and the ITA, on the right and on the left. Racial variations could contribute to an explanation of the differences observed by authors of different countries in the relationship between the RLN and the ITA

Asunto(s)