Aberrant branches of the subclavian artery and their relationship with the phrenic nerve and the brachial plexus / Ramas aberrantes de la arteria subclavia y su relación con el nervio frénico y el plexo braquial

SUMMARY: Variations in subclavian artery branches are relatively common and may impact surgical procedures and effects. During educational dissection of a male cadaver, we encountered an extremely rare variation of the right subclavian artery branches. The internal thoracic artery, the thyrocervical trunk, and the costocervical trunk arose from the third part of the right subclavian artery. In addition, the phrenic nerve displaced remarkably laterally by the thyrocervical trunk, and the course of the costocervical trunk was between the upper trunk and the middle trunk of the brachial plexus. These variations may pose a potential risk for nerve compression and increase the risk of arterial and nerve puncture. This case report would bring attention to the possibility of other similar cases, and early detection of these variations through diagnostic interventions is helpful to reduce postoperative complications.

RESUMEN: Las variaciones en las ramas de la arteria subclavia son relativamente comunes y pueden afectar los procedimientos y efectos quirúrgicos. Durante la disección educativa de un cadáver masculino, encontramos una variación extremadamente rara de las ramas de la arteria subclavia derecha. La arteria torácica interna, el tronco tirocervical y el tronco costocervical nacían de la tercera parte de la arteria subclavia derecha. Además, el nervio frénico se desplazaba lateralmente por el tronco tirocervical, y el trayecto del tronco costocervical se encontraba entre el tronco superior y el tronco medio del plexo braquial. Estas variaciones pueden suponer un riesgo potencial de compresión nerviosa y aumentar el riesgo de punción arterial y nerviosa. Este reporte de caso llamaría la atención sobre la posibilidad de otros casos similares, y la detección temprana de estas variaciones a través de diagnósticos es útil para reducir las complicaciones postoperatorias.

Pulmonary capacity of patients with total traumatic injury of the brachial plexus submitted to neurotization with the phrenic nerve: a case series / Capacidade pulmonar de pacientes com lesão traumática total do plexo braquial submetidos à neurotização com o nervo frênico: uma série de casos

Total traumatic injury often requires surgical intervention such as neurotization using the phrenic nerve with the aim to recover the elbow function. However, its repercussions on the respiratory kinematics are unknown. Objective: To evaluate the ribcage volume in tricompartments division, kinematics of Duty Cycle, and shortening velocity of the respiratory muscles after nerve phrenic transfer. Methods: Five participants (4 male), aged 18 to 40 years old (32±2), diagnosed with total brachial plexus injury and with nerve phrenic transfer. The optoelectronic plethysmography (OEP) was the instrument to evaluate volume in quiet breathing (QB), inspiratory capacity (IC) and vital capacity (VC) of the rib cage in its tricompartments division (pulmonary rib cage, abdominal rib cage and abdomen rib cage) and in each hemithorax, as well as the shortening velocity of the respiratory muscles, and respiratory rate. Assessments occurred 30 days prior and 30 days after surgery. Results: There was a decrease in the total compartmental distribution in QB with statistical difference only in the abdominal compartment (p <0.05). Four patients showed a reduction in the shortening speed of the left diaphragm muscle. It was not possible to perform a group analysis of respiratory kinematics and volumes in CV, IC due to the variation found in each patient analyzed. Conclusion: There was a reduction in volume in the rib cage as well as a change in the speed of shortening of the respiratory muscles after the transfer of the phrenic nerve one month after surgery.

A lesão traumática total freqüentemente requer intervenção cirúrgica, como neurotização usando o nervo frênico, com o objetivo de recuperar a função do cotovelo. No entanto, suas repercussões na cinemática respiratória são desconhecidas. Objetivo: Avaliar o volume da caixa torácica na divisão dos tricompartimentos, a cinemática do Duty Cycle e a velocidade de encurtamento dos músculos respiratórios após a transferência do nervo frênico. Métodos: Cinco participantes (4 do sexo masculino), com idade entre 18 e 40 anos (32 ± 2), com diagnóstico de lesão total do plexo braquial e transferência do nervo frênico. A pletismografia optoeletrônica (OEP) foi o instrumento para avaliar o volume na respiração silenciosa (QB), a capacidade inspiratória (IC) e a capacidade vital (VC) da caixa torácica em sua divisão tricompartimental (caixa torácica pulmonar, caixa torácica abdominal e caixa torácica do abdômen ) e em cada hemitórax, bem como a velocidade de encurtamento dos músculos respiratórios e a frequência respiratória. As avaliações ocorreram 30 dias antes e 30 dias após a cirurgia. Resultados: Houve diminuição da distribuição compartimental total no QB com diferença estatística apenas no compartimento abdominal (p <0,05). Quatro pacientes apresentaram redução da velocidade de encurtamento do músculo diafragma esquerdo. Não foi possível realizar uma análise de grupo da cinemática respiratória e dos volumes em CV, IC devido à variação encontrada em cada paciente analisado. Conclusão: Houve redução do volume da caixa torácica e também alteração da velocidade de encurtamento dos músculos respiratórios após a transferência do nervo frênico um mês após a cirurgia.

Estudio histopatológico comparativo del nervio frénico proveniente de cadáveres con enfermedad pulmonar obstructiva crónica y sin esta condición / Comparative Histopathological Study Of The Phrenic Nerve From Corpses With Chronic Obstructive Pulmonary Disease And Without This Condition

Introducción: Los cambios funcionales resultantes de la evolución de la enfermedad pulmonar obstructiva crónica (EPOC) son progresivos e irreversibles, lo que provoca un aumento del trabajo del diafragma debido a la hiperinflación. Los nervios frénicos promueven la inervación del diafragma y pueden verse comprometidos en la condición de EPOC.Objetivo: Comparar la morfología de los nervios frénicos de los cadáveres con y sin EPOC, mediante microscopía óptica. Métodos: Estudio descriptivo, transversal y comparativo de muestras, tanto de los pulmones como de los nervios frénicos de 38 cadáveres, con diagnóstico de EPOC y sin esta condición. Las muestras de tejido fueron fijadas y procesadas por histología convencional con láminas histológicas de hematoxilina-eosina. Las muestras fueron compuestas por pacientes con EPOC (EPOC) y sin EPOC (CTR). Esta clasificación se realizó después del análisis histológico. Las láminas histológicas se analizaron mediante microscopía óptica por un patólogo, que fue un evaluador ciego al estudio. Resultados: De acuerdo con los criterios de inclusión, se incluyeron 31 cadáveres en el grupo de EPOC y 7 cadáveres en el grupo CTR. En el análisis de los nervios frénicos, 8 cadáveres, es decir 25,8% del grupo de EPOC, tuvieron cambios histopatológicos como edema perineural (75%, n=6), atrofia nerviosa (12,5%, n=1) e infiltrado eosinofílico perineural (12,5%, n=1). Conclusión: Los nervios frénicos de los cadáveres con EPOC tienen tendencia a alteraciones histopatológicas, siendo el edema perineural la principal modificación encontrada

Introducción: Los cambios funcionales resultantes de la evolución de la enfermedad pulmonar obstructiva crónica (EPOC) son progresivos e irreversibles, lo que provoca un aumento del trabajo del diafragma debido a la hiperinflación. Los nervios frénicos promueven la inervación del diafragma y pueden verse comprometidos en la condición de EPOC.Objetivo: Comparar la morfología de los nervios frénicos de los cadáveres con y sin EPOC, mediante microscopía óptica. Métodos: Estudio descriptivo, transversal y comparativo de muestras, tanto de los pulmones como de los nervios frénicos de 38 cadáveres, con diagnóstico de EPOC y sin esta condición. Las muestras de tejido fueron fijadas y procesadas por histología convencional con láminas histológicas de hematoxilina-eosina. Las muestras fueron compuestas por pacientes con EPOC (EPOC) y sin EPOC (CTR). Esta clasificación se realizó después del análisis histológico. Las láminas histológicas se analizaron mediante microscopía óptica por un patólogo, que fue un evaluador ciego al estudio. Resultados: De acuerdo con los criterios de inclusión, se incluyeron 31 cadáveres en el grupo de EPOC y 7 cadáveres en el grupo CTR. En el análisis de los nervios frénicos, 8 cadáveres, es decir 25,8% del grupo de EPOC, tuvieron cambios histopatológicos como edema perineural (75%, n=6), atrofia nerviosa (12,5%, n=1) e infiltrado eosinofílico perineural (12,5%, n=1). Conclusión: Los nervios frénicos de los cadáveres con EPOC tienen tendencia a alteraciones histopatológicas, siendo el edema perineural la principal modificación encontrada

Hemidiaphragmatic paralysis after ultrasound-guided supraclavicular block: a prospective cohort study / Paralisia hemidiafragmática após bloqueio supraclavicular guiado por ultrassom: um estudo coorte prospectivo

Abstract Background and objectives: The frequent onset of hemidiaphragmatic paralysis during interscalene block restricts its use in patients with respiratory insufficiency. Supraclavicular block could be a safe and effective alternative. Our primary objective was to assess the incidence of hemidiaphragmatic paralysis following ultrasound-guided supraclavicular block and compare it to that of interscalene block. Methods: Adults warranting elective shoulder surgery under regional anesthesia (Toulouse University Hospital) were prospectively enrolled from May 2016 to May 2017 in this observational study. Twenty millilitres of 0.375% Ropivacaine were injected preferentially targeted to the "corner pocket". Diaphragmatic excursion was measured by ultrasonography before and 30 minutes after regional anesthesia. A reduction ≥25% in diaphragmatic excursion during a sniff test defined the hemidiaphragmatic paralysis. Dyspnoea and hypoxaemia were recorded in the recovery room. Predictive factors of hemidiaphragmatic paralysis (gender, age, weight, smoking, functional capacity) were explored. Postoperative pain was also analysed. Results: Forty-two and 43 patients from respectively the supraclavicular block and interscalene block groups were analysed. The incidence of hemidiaphragmatic paralysis was 59.5% in the supraclavicular block group compared to 95.3% in the interscalene block group (p < 0.0001). Paradoxical movement of the diaphragm was more common in the interscalene block group (RR = 2, 95% CI 1.4-3; p = 0.0001). A similar variation in oxygen saturation was recorded between patients with and without hemidiaphragmatic paralysis (p = 0.08). No predictive factor of hemidiaphragmatic paralysis could be identified. Morphine consumption and the highest numerical rating scale numerical rating scale (NRS) at 24 hours did not differ between groups. Conclusions: Given the frequent incidence of hemidiaphragmatic paralysis following supraclavicular block, this technique cannot be recommended for patients with an altered respiratory function.

Resumo Justificativa e objetivos: O aparecimento frequente de paralisia hemidiafragmática durante o bloqueio interescalênico restringe seu uso em pacientes com insuficiência respiratória. O bloqueio supraclavicular pode ser uma opção segura e eficaz. Nosso objetivo primário foi avaliar a incidência de paralisia hemidiafragmática após bloqueio supraclavicular guiado por ultrassom e compará-lo com o bloqueio interescalênico. Métodos: Os adultos agendados para cirurgia eletiva do ombro sob anestesia regional (Hospital Universitário de Toulouse) foram prospectivamente incluídos neste estudo observacional, de maio de 2016 a maio de 2017. Vinte mililitros de ropivacaína a 0,375% foram injetados, preferencialmente objetivando a interseção da primeira costela e da artéria subclávia. A excursão diafragmática foi medida por ultrassonografia antes e 30 minutos após a anestesia regional. Uma redução ≥ 25% na excursão diafragmática durante um sniff test definiu a paralisia hemidiafragmática. Dispneia e hipoxemia foram registradas na sala de recuperação. Fatores preditivos de paralisia hemidiafragmática (sexo, idade, peso, tabagismo, capacidade funcional) foram explorados. A dor pós-operatória também foi avaliada. Resultados: Quarenta e dois e 43 pacientes dos grupos bloqueio supraclavicular e bloqueio interescalênico, respectivamente, foram avaliados. A incidência de paralisia hemidiafragmática foi de 59,5% no grupo bloqueio supraclavicular em comparação com 95,3% no grupo bloqueio interescalênico (p < 0,0001). O movimento paradoxal do diafragma foi mais comum no grupo bloqueio interescalênico (RR = 2, 95% IC 1,4-3; p = 0,0001). Uma variação semelhante na saturação de oxigênio foi registrada entre os pacientes com e sem paralisia hemidiafragmática (p = 0,08). Nenhum fator preditivo de paralisia hemidiafragmática pôde ser identificado. O consumo de morfina e o maior escore na escala numérica (NRS) em 24 horas não diferiram entre os grupos. Conclusão: Devido à frequente incidência de paralisia hemidiafragmática após bloqueio supraclavicular, essa técnica não pode ser recomendada para pacientes com função respiratória alterada.

Post-thoracotomy ipsilateral shoulder pain: What should be preferred to optimize it - phrenic nerve infiltration or paracetamol infusion?

Background: Post thoracotomy ipsilateral shoulder pain (PTISP) is a distressing and highly prevalent problem after thoracic surgery and has not received much attention despite the incidence as high as 85%. Objectives: To study the effect of phrenic nerve infiltration with Ropivacaine compared to paracetamol infusion on PTISP in thoracotomy patients with epidural analgesia as standard mode of incisional analgesia in both the groups. Study Design: Prospective Randomised and Double Blind Study. Methods: 126 adult patients were divided randomly into 2 groups, “Group A (Phrenic Nerve Infiltration Group) received 10 mL of 0.2% Ropivacaine close to the diaphragm into the periphrenic fat pad” and “Group B (Paracetamol Infusion Group) received 20mg/kg paracetamol infusion” 30 minutes prior to chest closure respectively. A blinded observer assessed the patients PTISP using the VAS score at 1, 4, 8, 12 and 24 hours (h) postoperatively. The time and number of any rescue analgesic medication were recorded. Results: PTISP was relieved significantly in Group A (25.4℅) as compared to Group B (61.9℅), with significantly higher mean duration of analgesia in Group A. The mean time for first rescue analgesia was significantly higher in Group A (11.1 ± 7.47 hours) than in Group B (7.40 ± 5.30 hours). The number of rescue analgesic required was less in Group A 1.6 ± 1.16 as compared to Group B 2.9 ± 1.37 (P value <0.5). Conclusions: Phrenic Nerve Infiltration significantly reduced the incidence and delayed the onset of PTISP as compared to paracetamol infusion and was not associated with any adverse effects.

Effect of External Phrenic Nerve Electrical Stimulation on Respiratory Function for Convalescent Stroke Patients / 中国康复理论与实践

Objective:To observe the effect of external phrenic nerve electrical stimulation on respiratory function for convalescent stroke patients. Methods:From October, 2017 to July, 2018, 27 convalescent stroke patients were randomly divided into control group (n = 14) and observation group (n = 13). Both groups received routine rehabilitation, while the observation group accepted external phrenic nerve electrical stimulation additionaly. Their ventilation and respiratory muscle strength were measured before and four weeks after treatment. Results:The forced vital capacity (FVC), forced expiratory volume in 1st second (FEV1), peak expiratory flow (PEF), maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) improved in both groups after treatment (t > 5.075, Z = -3.366, P < 0.001), and improved more in FVC, FEV1, PEF and MIP in the observation group than in the control group (t > 0.921, Z = -2.746, P < 0.05). Conclusion:External phrenic nerve electrical stimulation can improve ventilation and inspiratory muscle strength for convalescent stroke patients.

Effect of External Phrenic Nerve Electrical Stimulation on Respiratory Function for Convalescent Stroke Patients / 中国康复理论与实践

Objective:To observe the effect of external phrenic nerve electrical stimulation on respiratory function for convalescent stroke patients. Methods:From October, 2017 to July, 2018, 27 convalescent stroke patients were randomly divided into control group (n = 14) and observation group (n = 13). Both groups received routine rehabilitation, while the observation group accepted external phrenic nerve electrical stimulation additionaly. Their ventilation and respiratory muscle strength were measured before and four weeks after treatment. Results:The forced vital capacity (FVC), forced expiratory volume in 1st second (FEV1), peak expiratory flow (PEF), maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) improved in both groups after treatment (t > 5.075, Z = -3.366, P < 0.001), and improved more in FVC, FEV1, PEF and MIP in the observation group than in the control group (t > 0.921, Z = -2.746, P < 0.05). Conclusion:External phrenic nerve electrical stimulation can improve ventilation and inspiratory muscle strength for convalescent stroke patients.

Performance and clinical comparison between left ventricular quadripolar and bipolar leads in cardiac resynchronization therapy: Observational research

Aim To evaluate Attain Performa (Medtronic, Dublin, Ireland) quadripolar lead performance in clinical practice and, secondarily, to compare its long term clinical outcomes vs bipolar leads for left ventricular (LV) pacing. Methods and results We retrospectively analyzed clinical, procedural and follow-up data of 215 patients implanted with a quadripolar lead. One hundred and twenty one patients implanted with bipolar lead were selected to compare long-term clinical outcomes. The quadripolar lead was implanted in the target vein in 196 patients (91%) without acute dislodgements. In 50% of patients the chosen final pacing configuration at implant would not have been available with bipolar leads. A dedicated quadripolar pacing vector was chosen more frequently when the LV tip location was apical than otherwise (65.6% vs 42.7%, p = 0.003). After a median follow-up of 14 months, the LV pacing threshold was less than 2.5 V at 0.4 ms in 98 patients (90%) with a safety margin between phrenic nerve and LV pacing threshold >3 V in 97 patients (89%). We observed a slight trend toward a lower risk of heart failure worsening and a lower incidence of ventricular arrhythmias and pulmonary congestion in patients implanted with quadripolar leads compared with the control group. Conclusion Quadripolar leads improve the management of phrenic nerve stimulation at no trade-off with pacing threshold and lead stability. Quadripolar leads seems to be associated with a lower incidence of VT/VF and pulmonary congestion, when compared with bipolar leads, but further investigations are necessary to confirm that this positive effect is associated with better LV reverse remodeling.

Cardiac resynchronization therapy: overcoming anatomical challenges / Terapia de ressincronização cardíaca: superando desafios anatômicos

A anatomia venosa coronária pode dificultar ou impossibilitar o implante com sucesso de um dispositivo de terapia de ressincronização cardíaca. O objetivo desta revisão foi o de apresentar uma abordagem interventiva com muitas técnicas e ferramentas que precisam ser aprendidas e conhecidas para melhorar os resultados desta terapia e a saúde dos pacientes

Coronary venous anatomy can make successful implantation of a cardiac resynchronization therapy device difficult or impossible. The aim of this review is introduce an interventional approach with many techniques and tools that are needed to be learned and known in order to improve the results of this therapy and the health of patients

Is phrenic nerve conduction affected in patients with difficult-to-treat asthma? / A neurocondução do nervo frênico está alterada na asma de difícil controle?

ABSTRACT Objective The aim of this study was to obtain data on phrenic neuroconduction and electromyography of the diaphragm muscle in difficult-to-treat asthmatic patients and compare the results to those obtained in controls. Methods The study consisted of 20 difficult-to-treat asthmatic patients compared with 27 controls. Spirometry, maximal inspiratory and expiratory pressure, chest X-ray, phrenic neuroconduction and diaphragm electromyography data were obtained. Results The phrenic compound motor action potential area was reduced, compared with controls, and all the patients had normal diaphragm electromyography. Conclusion It is possible that a reduced phrenic compound motor action potential area, without electromyography abnormalities, could be related to diaphragm muscle fiber abnormalities due to overload activity.

RESUMO Objetivo O objetivo do presente estudo foi obter dados da neurocondução do frênico e exame com agulha do diafragma em pacientes com asma de difícil controlee comparar com um grupo normal. Métodos O estudo consiste em realizar radiografia de tórax, espirometria, pressão máxima inspiratória e expiratória, neurocondução do nervo frênico e eletromiografia do músculo diafragma em 20 pacientes asmáticos de difícil controle e comparar com 27 controles. Resultados Encontramos redução da área do potencial de ação muscular composto do nervo frênico e a eletromiografia do musculo diafragma estava normal em todos os pacientes. Conclusão É possível que a redução da área do potencial de ação muscular composto do nervo frênico nos pacientes com asma de difícil controle associado a eletromiografia normal do músculo diafragma esteja relacionada as alterações da fibra muscular do mesmo devido à sobrecarga de atividade.

Cervical plexus block / 대한마취과학회지

Cervical plexus blocks (CPBs) have been used in various head and neck surgeries to provide adequate anesthesia and/or analgesia; however, the block is performed in a narrow space in the region of the neck that contains many sensitive structures, multiple fascial layers, and complicated innervation. Since the intermediate CPB was introduced in addition to superficial and deep CPBs in 2004, there has been some confusion regarding the nomenclature and definition of CPBs, particularly the intermediate CPB. Additionally, as the role of ultrasound in the head and neck region has expanded, CPBs can be performed more safely and accurately under ultrasound guidance. In this review, the authors will describe the methods, including ultrasound-guided techniques, and clinical applications of conventional deep and superficial CPBs; in addition, the authors will discuss the controversial issues regarding intermediate CPBs, including nomenclature and associated potential adverse effects that may often be neglected, focusing on the anatomy of the cervical fascial layers and cervical plexus. Finally, the authors will attempt to refine the classification of CPB methods based on the target compartments, which can be easily identified under ultrasound guidance, with consideration of the effects of each method of CPB.

Thoracoscopic Patch Insulation for Phrenic Nerve Stimulation after Permanent Pacemaker Implantation

One of the complications of permanent pacemaker implantation is unintended phrenic nerve stimulation. A 15-year-old boy with a permanent pacemaker presented with chest discomfort due to synchronous chest wall contraction with pacing beats. Even after reprogramming of the pacemaker, diaphragmatic stimulation persisted. Therefore, we performed thoracoscopic phrenic nerve insulation using a Gore-Tex patch to insulate the phrenic nerve from the wire. A minimally invasive approach using a thoracoscope is a feasible option for retractable phrenic nerve stimulation after pacemaker implantation.

The effect of phrenic nerve electrical stimulation combined with respiratory training on lung function and on the trunk stability and balance of stroke survivors / 中华物理医学与康复杂志

Objective To observe the effect of phrenic nerve electrical stimulation combined with respiratory training on the pulmonary function,trunk stability and balance of stroke survivors.Methods Thirty-six stroke survivors were randomly divided into a control group and a training group,each of 28.Both groups were given routine rehabilitation treatment (including physical agent therapy and combined training of the limbs),while the training group was additionally provided with phrenic nerve electrical stimulation combined with respiratory training once a day for six weeks.Before and after the treatment,the forced vital capacity (FVC),forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) of both groups were recorded.The Sheikh trunk control scale (TCT) was used to quantify their trunk stability,and balance was quantified using the Berg balance function scale (BBS).Results After six weeks of treatment the average FVC,FEV1 and PEF values of the training group were significantly higher than before the treatment,and significantly better than those of the control group after the treatment.Moreover,significant improvement was observed in the average TCT and BBS scores of both groups after the intervention,with the training group's average significantly higher than that of the contrcl group.Conclusion Phrenic nerve electrical stimulation combined with respiratory training can further improve the pulmonary function and balance function of stroke survivors as a supplement to routine rehabilitation treatment.Therefore,it is worth popularizing in clinical practice.

Usefulness of phrenic nerve conduction study in early diagnosis of isolated respiratory onset amyotrophic lateral sclerosis

Isolated respiratory onset amyotrophic lateral sclerosis (ALS) is a rare clinical manifestation and the diagnosis can be challenging. A 72-year-old man presented with dyspnea and hypercapnia that had started 11 months earlier. A phrenic nerve study was conducted and he was diagnosed promptly with ALS with no significant time delay. The phrenic nerve study is a noninvasive and useful tool in the diagnosis of respiratory onset ALS that can be applied easily in an emergency department.

Phrenic Nerve Clipping in a Stroke Patient with Intractable Hiccup: a Case Report

Hiccup is an intermittent, involuntary and erratic contraction of the diaphragm, immediately followed by a laryngeal closure. Persistent and intractable hiccups are rare but severe, keeping a person from doing daily activities; these can result in depression, fatigue, impaired sleep, dehydration, weight loss, malnutrition, and aspiration. Therefore, proper treatments are necessary. We present a case with intractable hiccup treated with an unusual treatment. A 61-year-old man presented with intractable hiccups, which started 6 years ago after subarachnoid and intraventricular hemorrhage. Conventional pharmacologic treatments including metoclopramide, gabapentin, and baclofen were unsuccessful. Cooperating with cardiothoracic surgeons, phrenic nerve clipping operation was done under intraoperative electrophysiologic monitoring. This method was successful that the symptoms were relieved. Reversible clipping done under intraoperative electrophysiologic monitoring can be a promising therapeutic method for persistent and intractable hiccups in patients with stroke.

Phrenic nerve conduction studies: normative data and technical aspects / Aspectos técnicos e normatização da neurocondução do nervo frênico

ABSTRACT Objective: The aim of the present study was to define normative data of phrenic nerve conduction parameters of a healthy population. Methods: Phrenic nerve conduction studies were performed in 27 healthy volunteers. Results: The normative limits for expiratory phrenic nerve compound muscle action potential were: amplitude (0.47 mv - 0.83 mv), latency (5.74 ms - 7.10 ms), area (6.20 ms/mv - 7.20 ms/mv) and duration (18.30 ms - 20.96 ms). Inspiratory normative limits were: amplitude (0.67 mv - 1.11 mv), latency (5.90 ms - 6.34 ms), area (5.62 ms/mv - 6.72 ms/mv) and duration (13.77 ms - 15.37 ms). Conclusion: The best point of phrenic nerve stimulus in the neck varies among individuals between the medial and lateral border of the clavicular head of the sternocleidomastoid muscle and stimulation of both sites, then choosing the best phrenic nerve response, seems to be the appropriate procedure.

RESUMO Objetivo: O objetivo do presente estudo foi definir os dados normativos de condução do nervo frênico de uma população saudável. Métodos: Foram realizados estudos de condução do nervo frênico em 27 voluntários saudáveis. Resultados: Os limites normais do potencial de ação muscular composto do nervo frênico durante a expiração foram: amplitude (0.47 mv - 0.83 mv), latência (5.74 ms - 7.10 ms), área (6.20 ms/mv - 7.20 ms/mv) e duração (18.30 ms - 20.96 ms). E durante a inspiração os limites normais foram: amplitude (0.67 mv - 1.11 mv), latência (5.90 ms - 6.34 ms), área (5.62 ms/mv - 6.72 ms/mv) e duração (13.77 ms - 15.37 ms). Conclusão: O melhor ponto de estímulo do nervo frênico no pescoço varia entre a borda medial e lateral da cabeça clavicular do músculo esternocleidomastóideo. Estimular ambos os locais e escolher a melhor resposta do nervo frênico parece ser o procedimento mais adequado.

Treatment of bilateral vocal cord paralysis by hemi-phrenic nerve transfer / 中华耳鼻咽喉头颈外科杂志

Objective@#To investigate the surgical effect of reinnervation of bilateral posterior cricoarytenoid muscles(PCA) with left hemi-phrenic nerve and endoscopic laser arytenoid resection in bilateral vocal cord fold paralysis(BVFP) and to analyze the pros and cons of the two methods.@*Methods@#One hundred and seventeen BVFP patients who underwent reinnervation of bilateral PCA using the left hemi-phrenic nerve approach (nerve group, n=52) or laser arytenoidectomy(laser group, n=65) were enrolled in this study from Jan.2009 to Dec.2015.Vocal perception evaluation, video stroboscopy, pulmonary function test and laryngeal electromyography were preformed in all patients both preoperatively and postoperative1y.Extubution rate was calculated postoperative1y.@*Results@#Most of the vocal function parameters in nerve group were improved postoperatively compared with preoperative parameters, albeit without a significant difference(P>0.05), while laser group showed a significant deterioration in voice quality postoperative1y(P<0.05). The two groups showed significant difference in voice quality postoperative1y(P<0.05). Videostroboscopy showed that vocal fold on the operated side in both groups could abduct to various extent postoperatively, which showed significant difference when compared with preoperative abductive movements (P<0.05). But the amplitude in nerve group was larger than that in laser group (P<0.05). 89% of the patients in nerve group were inhale physiological vocal cord abductions. Postoperative glottal closure showed no significant difference in nerve group (P>0.05), while showed various increment in laser group(P<0.05). Differences between the two groups were statistically significant(P<0.05). The pulmonary function in both groups was better after operation, reaching the reference value. Postoperative laryngeal electromyography confirmed successful reinnervation of the bilateral PCA muscles. The decannulation rate were 88.5% and 81.5% in nerve group and laser group respectively. In both groups, patients presented aspiration symptoms postoperatively, and rdieved soon, except 2 patients in laser group suffered repeated aspiration.@*Conclusions@#Reinnervation of bilateral PCA muscles using left hemi-phrenic nerve can restore inspiratory vocal fold abduction to a satisfactory extent while preserving phonatory function at the preoperative level without evident morbidity, and do not affect swallowing function, greatly improving the quality of life of the patients.

Selective Reinnervation of Posterior Cricoarytenoidmuscles by Upper Root of Unilateral Phrenic Cerve / 听力学及言语疾病杂志

Objective To study the experimental results of selective reinnervation of posterior cricoarytenoid(PCA) muscles by upper root of unilateral phrenic nerve.Methods Eight beagle dogs were used in this experiment.The left recurrent laryngeal nerves (RLNs) were severed and anastomosed with upper root of phrenic nerve, and the intralaryngeal adductor branch was cut and sutured into the belly of the ipsilateral PCA muscle. The right RLNs were kept intact, and were used as control group.Videolaryngoscopy and electromyography (EMG) were performed at preoperative, immediately after surgery and 6 months after surgery.After completion of all physiologic testings,the dogs were sacrificed and bilateral PCA muscles and intralaryngeal part of recurrent laryngeal nerves were harvested, then histological examination was carried out.The laryngeal nerve was stained with toluidine blue and the morphology of the axons was observed under light microscope.Results Preoperatively, the movement of bilateral vocal folds were normal in all dogs.The left vocal folds were fixed immediately after surgery, 6 months after surgery, the left vocal folds in all 8 dogs recovered inspiratory abductive movement.Spontaneous and evoked electrical activities of the reinnervated PCA muscles could be recorded in all cases during inspiration preoperatively.The left PCA muscles were electrical silent during normal inspiration, and evoked activities were not induced immediately after surgery.Spontaneous electrical activities and evoked electrical activities were recorded 6 months after surgery, and had no significant difference when compared with those of postoperative (P>0.05).There was no significant difference in the cross-sectional area of the bilateral posterior cricoarytenoid muscles fibers after the masson staining.Muscle collagen relative cross-sectional area and collagen relative cross-sectional area and muscle/collagen cross-sectional area ratio difference were not statistically significant(P>0.05).Nerve pulp numbers of left and right sides of the recurrent laryngeal nerves had no significant difference (P>0.05).Conclusion Selective reinnervation of posterior cricoarytenoid muscles by the upper root of unilateral phrenic nerve can restore inspiratory vocal fold abduction to a satisfactory extent and avoid aberrant regeneration.

Sonoanatomical Change of Phrenic Nerve According to Posture During Ultrasound-Guided Stellate Ganglion Block

OBJECTIVE: To evaluate the risk of phrenic nerve injury during ultrasound-guided stellate ganglion block (US-SGB) according to sonoanatomy of the phrenic nerve, and determine a safer posture for needle insertion by assessing its relationship with surrounding structure according to positional change. METHODS: Twenty-nine healthy volunteers were recruited and underwent ultrasound in two postures, i.e., supine position with the neck extension and head rotation, and lateral decubitus position. The transducer was placed at the anterior tubercle of the C6 level to identify phrenic nerve. The cross-sectional area (CSA), depth from skin, distance between phrenic nerve and anterior tubercle of C6 transverse process, and the angle formed by anterior tubercle, posterior tubercle and phrenic nerve were measured. RESULTS: The phrenic nerve was clearly identified in the intermuscular fascia layer between the anterior scalene and sternocleidomastoid muscles. The distance between the phrenic nerve and anterior tubercle was 10.33±3.20 mm with the supine position and 9.20±3.31 mm with the lateral decubitus position, respectively. The mean CSA and skin depth of phrenic nerve were not statistically different between the two positions. The angle with the supine position was 48.37°±27.43°, and 58.89°±30.02° with the lateral decubitus position. The difference of angle between the two positions was statistically significant. CONCLUSION: Ultrasound is a useful tool for assessing the phrenic nerve and its anatomical relation with other cervical structures. In addition, lateral decubitus position seems to be safer by providing wider angle for needle insertion than the supine position in US-SGB.

Delayed Onset Transient Diaphragmatic Paralysis after Pacemaker Implantation

A 77-year-old woman presented with exertional dyspnea six days after left pectoral pacemaker implantation. Chest radiography at presentation showed that her left diaphragm was elevated when compared to earlier films. A fluoroscopic sniff test confirmed left diaphragmatic paralysis. Thoracic computed tomography did not reveal any major vascular or lung parenchymal injury; however, phrenic nerve injury on direct needle puncture during the original surgery was suspected. The patient's small body size may have increased the risk of this injury. Delayed-onset unilateral diaphragmatic paralysis appears to be a rare complication of cardiac device implantation.