Fiber-reinforced silicone for tracheobronchial stents: An experimental study.

A trachea is a tubular structure composed of smooth muscle that is reinforced with cartilage rings. Some diseases can cause sagging in smooth muscle and cartilaginous tissue. The end result is reduction (narrowing) of the trachea diameter. A solution to this problem is the use of tracheal stents, which are small tubular devices made of silicone. One is inserted into the trachea to prevent or correct its constriction. The purpose of tracheal stent use is to maintain cartilage support that would otherwise be lost in the airway. Current tracheal stent models present limitations in terms of shape and characteristics of the silicone used in their production. One of the most important is the large thickness of the wall, which makes its placement difficult; this mainly applies to pediatric patients. The wall thickness of the stent is closely related to the mechanical properties of the material. This study aims to test the reinforcement of silicone with three kinds of fibers, and then stents that were produced using fiber with the best compressive strength characteristics. Silicone samples were reinforced with polypropylene (PP), polyamide (PA), and carbon fiber (CF) at concentrations of 2% and 4% (vol%), which then underwent tensile strength and Shore A hardness testing. Samples with fiber showed good characteristics; surface analyses were carried out and they were used to produce stents with an internal diameter of 11 or 13mm and a length of 50mm. Stents underwent compression tests for qualitative evaluation. Samples with 2% and 4% CF blends showed the best mechanical performance, and they were used to produce stents. These samples presented similar compressive strengths at low deformation, but stents with a 4% CF blend exhibited improved compressive strength at deformations greater than 30-50% of their diameter (P ≤ 0.05). The addition of 2% and 4% CF blends conferred greater mechanical strength and resistance to the silicone matrix. This is particularly true at low deformation, which is the condition where the stent is used when implanted. In the finite element compression strength tests, the stent composite showed greater compression strength with the addition of fiber, and the results were in accordance with mechanical compression tests performed on the stents. In vivo tests showed that, after 30 days of post-implantation in sheep trachea, an inflammatory process occurred in the region of the trachea in contact with the stent composite and with the stent without fiber (WF). This response is a common process during the first few days of implantation.

Chylothorax after surgical treatment of right-sided thoracic outlet syndrome.

Chylothorax as a complication of the surgical treatment of thoracic outlet syndrome is a quite rare event. We report a case of right-sided chylothorax and present a brief review on the treatment of postoperative chylothorax.

Fístula linfática após tratamento cirúrgico de síndrome do desfiladeiro torácico à direita / Chylothorax after surgical treatment of right-sided thoracic outlet syndrome

A fístula linfática como complicação de correção de síndrome do desfiladeiro torácico é um evento muito raro. Relatamos um caso de fístula linfática à direita e apresentamos uma breve revisão do tratamento de quilotórax pós-cirúrgico.

Chylothorax as a complication of the surgical treatment of thoracic outlet syndrome is a quite rare event. We report a case of right-sided chylothorax and present a brief review on the treatment of postoperative chylothorax.

Aggressive treatment using muscle flaps or omentopexy in infections of the sternum and anterior mediastinum following sternotomy.

OBJECTIVE: To evaluate the impact of an aggressive treatment approach using muscle flaps or omentopexy in infections of the sternum and anterior mediastinum following sternotomy on mortality, as compared to that of a conservative treatment approach. METHODS: Data were collected prior to, during and after the surgical procedures. Group A (n = 44) included patients submitted to conservative treatment-debridement together with resuture or continuous irrigation with polyvinylpyrrolidone-iodine solutions, or even with second-intention wound healing (retrospective data). Group B (n = 9) included patients in whom infection was not resolved with conservative treatment, and who therefore underwent aggressive treatment (intermediate phase). Group C (n = 28) included patients primarily submitted to aggressive treatment (prospective data). RESULTS: Postoperative hospital stays were shorter in the patients submitted to aggressive treatment (p < 0.046). There were 7 deaths in group A, 1 in group B, and 2 in group C. However, the classical level of significance of alpha = 0.05 was not reached. CONCLUSION: Aggressive treatment also proved to be effective when the infection was not resolved with conservative treatment. These findings demonstrate that the proposed treatment provides excellent results.

Tratamento agressivo com retalho muscular e/ou omentopexia nas infecções do esterno e mediastino anterior em pós-operatório de esternotomia / Aggressive treatment using muscle flaps or omentopexy in infections of the sternum and anterior mediastinum following sternotomy

OBJETIVO: Avaliar o impacto do tratamento agressivo com retalho muscular e/ou omentopexia nas infecções do esterno e mediastino anterior em pós-operatório de esternotomia sobre a mortalidade, comparando-o ao do tratamento conservador. MÉTODOS: Foram coletados dados pré-, trans- e pós-operatórios. O grupo A (n = 44) incluiu pacientes submetidos ao tratamento conservador-desbridamento associado a ressutura e/ou a irrigação contínua com solução de polivinilpirrolidona-iodo, ou ainda a cicatrização por segunda intenção (dados retrospectivos). O grupo B (n = 9) incluiu pacientes nos quais não houve resolução da infecção com o tratamento conservador e que, por isso, foram submetidos ao tratamento agressivo (fase intermediária). O grupo C (n = 28) incluiu pacientes submetidos primariamente ao tratamento agressivo (dados prospectivos). RESULTADOS: Identificou-se menor tempo de internação pós-operatória nos pacientes submetidos ao tratamento agressivo (p < 0,046). Houve 7 óbitos no grupo A, 1 no grupo B e 2 no grupo C. Entretanto, o nível de significância clássico de α = 0,05 não foi atingido. CONCLUSÕES: O tratamento agressivo mostrou-se também adequado para aquelas infecções em que o tratamento conservador não foi resolutivo. Esses achados demonstram que o tratamento proposto tem excelentes resultados.

OBJECTIVE: To evaluate the impact of an aggressive treatment approach using muscle flaps or omentopexy in infections of the sternum and anterior mediastinum following sternotomy on mortality, as compared to that of a conservative treatment approach. METHODS: Data were collected prior to, during and after the surgical procedures. Group A (n = 44) included patients submitted to conservative treatment-debridement together with resuture or continuous irrigation with polyvinylpyrrolidone-iodine solutions, or even with second-intention wound healing (retrospective data). Group B (n = 9) included patients in whom infection was not resolved with conservative treatment, and who therefore underwent aggressive treatment (intermediate phase). Group C (n = 28) included patients primarily submitted to aggressive treatment (prospective data). RESULTS: Postoperative hospital stays were shorter in the patients submitted to aggressive treatment (p < 0.046). There were 7 deaths in group A, 1 in group B, and 2 in group C. However, the classical level of significance of α = 0.05 was not reached. CONCLUSION: Aggressive treatment also proved to be effective when the infection was not resolved with conservative treatment. These findings demonstrate that the proposed treatment provides excellent results.

A correção das estenoses traqueobrônquicas mediante o emprego de órteses / Therapeutic management of tracheobronchial stenosis with stent application

O tratamento cirúrgico do paciente com estenose traqueobrônquica exige uma avaliação individualizada em razão da complexidade de sua origem, sendo a traqueoplastia considerada a modalidade ideal. As causas mais comuns de estenose são devidas à intubação traqueal e ao desenvolvimento de neoplasias e estas condições são justamente as que mais se beneficiam com o tratamento endoscópico quando a correção cirúrgica não está indicada. Na atualidade, os meios endoscópicos incluem a aplicação de diversos tipos de laser e sondas de dilatação, habitualmente com o uso de broncoscópio rígido, e emprego de radioterapia e órteses, separadamente ou em associação. Basicamente, as órteses são de dois tipos: metálicas e de silicone. As metálicas têm sua indicação mais freqüente para os casos de traqueomalacia e estenoses por compressão neoplásica extrínseca. Nos casos de obstrução da via aérea por inflamação aguda, restrita à sua luz ou sem envolvimento mais profundo da parede traqueobrônquica, ou em presença de neoplasia endoluminal, é recomendável a órtese de silicone. Embora em algumas situações essas diversas formas de tratamento possam ser intercambiáveis, não costumam ser a regra. Portanto, a estratégia terapêutica visando à resolução mais eficaz da estenose traqueobrônquica baseia-se na seleção dos métodos empregados desde o primeiro tratamento