RESUMO
BACKGROUND: Advanced bipolar and ultrasonic energy have demonstrated reduction of operating time and blood loss in thyroidectomy. However, these devices generate heat and thermal dispersion that may damage adjacent structures such as the recurrent laryngeal nerve (RLN). This study was designed to evaluate the safety profile of the Harmonic Focus+® (HF+) device through the evaluation of thermal injury to the RLN using different algorithms of distance and time with state of the art technology. METHODS: 25 Vietnamese pigs underwent activation of HF+ in the proximity of their RLN. They were divided into 4 groups according to activation distance (3 mm, 2 mm, 1 mm and on the RLN). Time of activation, time between tones of the ultrasonic generator, changes in the electromyographic signal using continuous nerve neuromonitoring, vocal fold mobility assessed by direct laryngoscopy and histological thermal damaged were evaluated. RESULTS: None of the pigs had loss of signal in the electromyography during the procedure; only one pig had isolated transient decrease in amplitude and one increase in latency. One pig had transient vocal fold paresis in the group with activation on the nerve. Evaluation of the nerves by histology and immunohistochemistry did not show significant changes attributed to thermal injury. CONCLUSIONS: The use of ultrasonic energy close to the RLN is safe, provided that activation time does not exceed the necessary time to safely transect the tissue.
Assuntos
Hemostasia Cirúrgica/instrumentação , Complicações Intraoperatórias/prevenção & controle , Traumatismos do Nervo Laríngeo Recorrente/prevenção & controle , Procedimentos Cirúrgicos Ultrassônicos/instrumentação , Animais , Eletromiografia , Hemostasia Cirúrgica/efeitos adversos , Temperatura Alta/efeitos adversos , Complicações Intraoperatórias/diagnóstico , Complicações Intraoperatórias/etiologia , Complicações Intraoperatórias/patologia , Monitorização Intraoperatória , Traumatismos do Nervo Laríngeo Recorrente/diagnóstico , Traumatismos do Nervo Laríngeo Recorrente/etiologia , Traumatismos do Nervo Laríngeo Recorrente/patologia , Suínos , Tireoidectomia/efeitos adversos , Tireoidectomia/instrumentação , Tireoidectomia/métodos , Fatores de Tempo , Procedimentos Cirúrgicos Ultrassônicos/efeitos adversosRESUMO
BACKGROUND: Recurrent nerve injury is 1 of the most important complications of thyroidectomy. During the last decade, nerve monitoring has gained increasing acceptance in several centers as a method to predict and to document nerve function at the end of the operation. We evaluated the efficacy of a nerve monitoring system in a series of patients who underwent thyroidectomy and critically analyzed the negative predictive value (NPV) and positive predictive value (PPV) of the method. METHODS: NIM System efficacy was prospectively analyzed in 447 patients who underwent thyroidectomy between 2001 and 2008 (366 female/81 male; 420 white/47 nonwhite; 11 to 82 years of age; median, 43 years old). There were 421 total thyroidectomies and 26 partial thyroidectomies, leading to 868 nerves at risk. The gold standard to evaluate inferior laryngeal nerve function was early postoperative videolaryngoscopy, which was repeated after 4 to 6 months in all patients with abnormal endoscopic findings. RESULTS: At the early evaluation, 858 nerves (98.8%) presented normal videolaryngoscopic features after surgery. Ten paretic/paralyzed nerves (1.2%) were detected (2 unexpected unilateral paresis, 2 unexpected bilateral paresis, 1 unexpected unilateral paralysis, 1 unexpected bilateral paralyses, and 1 expected unilateral paralysis). At the late videolaryngoscopy, only 2 permanent nerve paralyses were noted (0.2%), with an ultimate result of 99.8% functioning nerves. Nerve monitoring showed absent or markedly reduced electrical activity at the end of the operations in 25/868 nerves (2.9%), including all 10 endoscopically compromised nerves, with 15 false-positive results. There were no false-negative results. Therefore, the PPV was 40.0%, and the NPV was 100%. CONCLUSIONS: In the present series, nerve monitoring had a very high PPV but a low NPV for the detection of recurrent nerve injury.
Assuntos
Estimulação Elétrica/métodos , Traumatismos do Nervo Laríngeo Recorrente/diagnóstico , Tireoidectomia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Humanos , Laringoscopia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico , Valor Preditivo dos Testes , Tireoidectomia/efeitos adversos , Paralisia das Pregas Vocais/prevenção & controle , Adulto JovemRESUMO
Paralisia das pregas vocais é causa frequente de rouquidão, podendo ser secundária a várias lesões ao longo do trajeto do X par craniano e seus ramos, particularmente os nervos laríngeos recorrentes. Apesar de grande parte dos casos ser idiopática, os métodos de imagem são muito importantes na pesquisa de fatores etiológicos, tais como lesões neoplásicas da tireoide e esôfago com invasão secundária dos nervos laríngeos recorrentes. Além destas, outras anormalidades como aneurismas do arco aórtico e da artéria subclávia direita podem ser encontradas. É fundamental que o radiologista conheça a anatomia pertinente a esta região e as principais afecções que podem ocorrer, para que o estudo seja corretamente planejado, auxiliando o diagnóstico e o planejamento terapêutico. Além disso, como até 35 por cento dos casos de paralisia da prega vocal são assintomáticos, o conhecimento dos sinais radiológicos que indicam esta condição é indispensável, cabendo ao radiologista alertar o médico assistente sobre os achados do exame. Neste trabalho realizamos uma revisão da anatomia e das principais doenças responsáveis pela paralisia de cordas vocais, demonstrando-as por meio de estudos de tomografia computadorizada e ressonância magnética de casos típicos. Mostramos, também, as alterações radiológicas próprias da laringe que indicam a presença de paralisia das pregas vocais.
Vocal cord paralysis is a common cause of hoarseness. It may be secondary to many types of lesions along the cranial nerve X pathway and its branches, particularly the laryngeal recurrent nerves. Despite the idiopathic nature of a great number of cases, imaging methods play a very significant role in the investigation of etiologic factors, such as thyroid and esophagus neoplasias with secondary invasion of the laryngeal recurrent nerves. Other conditions such as aortic and right subclavian artery aneurysms also may be found. The knowledge of local anatomy and related diseases is of great importance for the radiologist, so that he can tailor the examination properly to allow an appropriate diagnosis and therapy planning. Additionally, considering that up to 35 percent of patients with vocal cord paralysis are asymptomatic, the recognition of radiological findings indicative of this condition is essential for the radiologist who must warn the referring physician on the imaging findings. In the present study, the authors review the anatomy and main diseases related to vocal cord paralysis, demonstrating them through typical cases evaluated by computed tomography and magnetic resonance imaging, besides describing radiological findings of laryngeal abnormalities indicative of this condition.