A Prototype Implantable Artificial Bronchus Reduces Lung Hyperinflation in Recently Deceased Patients with Emphysema.

BACKGROUND: Several minimally invasive treatments have been offered to patients with severe emphysema over the last two decades. Currently, endobronchial valves (EBVs) are the only approved therapeutic option, but this method has drawbacks: only a few can undergo this therapy and the incidence of pneumothorax remains high. A minimally invasive technique, appropriate for a broader patient population and posing fewer risks, would represent a desirable alternative to improve lung function in these patients. OBJECTIVE: The objective of this study was to demonstrate whether a new prototype implantable artificial bronchus (IAB) releases trapped air from the lungs of recently deceased patients with emphysema. METHOD: Seven recently deceased patients with emphysema were mechanically ventilated and the respiratory rate increased from 12 bpm (resting) to 30 bpm (exercise), inducing air trapping and dynamic hyperinflation. This protocol was performed twice, before and after IAB placement. Ventilation parameters and the fraction of inspired oxygen were similar in all patients. Respiratory system plateau pressure (Pplat,rs) and intrinsic positive end-expiratory pressure (iPEEP) were measured. RESULTS: IAB implantation significantly reduced Pplat,rs (p = 0.017) in 6 of 7 deceased patients with emphysema and iPEEP (p = 0.03) in 5 of 7 patients. CONCLUSIONS: Placement of one or two IABs in segmental bronchi (up to 15th generation) proved to be feasible and improved lung function. These findings should provide a basis for subsequent clinical studies to assess the safety and efficacy of IAB in patients with emphysema, as well as identify short- and long-term effects of this innovative procedure.

Fissure Integrity and Volume Reduction in Emphysema: A Retrospective Study.

BACKGROUND: One-way endobronchial valves (EBVs) relieve symptoms of emphysema, particularly in patients without collateral ventilation between the target and adjacent lobes. Pretreatment knowledge of fissure integrity could serve as an aid in indicating EBV interventions. OBJECTIVE: This study aimed to investigate the relationship between software-measured lung fissure integrity and clinically relevant lung volume reduction (≥350 ml) in emphysema patients treated with one-way EBVs using a lobar exclusion strategy. METHODS: Of 108 patients treated between March 2008 and July 2014, 38 had both baseline and follow-up computed tomography (CT) scans acquired following a specific protocol for quantitative CT analysis and were included in the study (total of 39 treatments, two lungs treated in 1 patient). Outcome measures were fissure integrity measured on baseline CT scans, difference between pre- and postoperative lung volume (considering the lowest measured postoperative volume), and correlation between fissure integrity and volume change. RESULTS: Fissure integrity ≥75% correlated with volume reduction ≥350 ml (Spearman coefficient: -0.65; p < 0.01). The mean and median volume reductions were 1,223.96 ± 907.5 ml and 663 ml, respectively, for lungs with fissure integrity ≥75% (n = 31). The accuracy of fissure integrity ≥75% in predicting a volume reduction was 87.2%. The positive predictive value of fissure integrity ≥75% to predict a volume reduction ≥350 ml was 83.9%, and it was 70% for fissure integrity 75-90% and 90.5% for fissure integrity >90%. CONCLUSIONS: A target lobe volume reduction using EBVs is possible with lung fissure integrity ≥75%. For patients with fissure integrity between 75 and 90%, a further evaluation of interlobar ventilation should be performed. A clinically relevant volume reduction following treatment with EBVs is likely with any level of fissure integrity >90%.

Polydimethylsiloxane/nano calcium phosphate composite tracheal stents: Mechanical and physiological properties.

In this study, we report the production and characterization of tracheal stents composed of polydimethylsiloxane/nanostructured calcium phosphate composites obtained by reactive synthesis. Tracheal stents were produced by transfer molding, and in vivo tests were carried out. PDMS was combined with H3 PO4 and Ca(OH)2 via an in situ reaction to obtain nanoparticles of calcium phosphate dispersed within the polymeric matrix. The incorporation of bioactive inorganic substances, such as calcium phosphates, improved biological properties, and the in situ reaction allowed tight coupling of particles to the matrix. Results showed the presence of the nanoparticles of DCPA and CDHA. The porosity generated during mixing decreased the tensile strength and tear properties. Composites presented higher values of cell viability compared with those for PDMS. In vivo tests indicated the presence of inflammatory tissue 30 days after implantation in both cases. Thus, the present biomaterial shows potential for application in tracheal disease, however further evaluation is needed. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 545-553, 2019.

Combined Bone Marrow-Derived Mesenchymal Stromal Cell Therapy and One-Way Endobronchial Valve Placement in Patients with Pulmonary Emphysema: A Phase I Clinical Trial.

One-way endobronchial valves (EBV) insertion to reduce pulmonary air trapping has been used as therapy for chronic obstructive pulmonary disease (COPD) patients. However, local inflammation may result and can contribute to worsening of clinical status in these patients. We hypothesized that combined EBV insertion and intrabronchial administration of mesenchymal stromal cells (MSCs) would decrease the inflammatory process, thus mitigating EBV complications in severe COPD patients. This initial study sought to investigate the safety of this approach. For this purpose, a phase I, prospective, patient-blinded, randomized, placebo-controlled design was used. Heterogeneous advanced emphysema (Global Initiative for Chronic Lung Disease [GOLD] III or IV) patients randomly received either allogeneic bone marrow-derived MSCs (108 cells, EBV+MSC) or 0.9% saline solution (EBV) (n = 5 per group), bronchoscopically, just before insertion of one-way EBVs. Patients were evaluated 1, 7, 30, and 90 days after therapy. All patients completed the study protocol and 90-day follow-up. MSC delivery did not result in acute administration-related toxicity, serious adverse events, or death. No significant between-group differences were observed in overall number of adverse events, frequency of COPD exacerbations, or worsening of disease. Additionally, there were no significant differences in blood tests, lung function, or radiological outcomes. However, quality-of-life indicators were higher in EBV + MSC compared with EBV. EBV + MSC patients presented decreased levels of circulating C-reactive protein at 30 and 90 days, as well as BODE (Body mass index, airway Obstruction, Dyspnea, and Exercise index) and MMRC (Modified Medical Research Council) scores. Thus, combined use of EBV and MSCs appears to be safe in patients with severe COPD, providing a basis for subsequent investigations using MSCs as concomitant therapy. Stem Cells Translational Medicine 2017;6:962-969.

Transbronchoscopic pulmonary emphysema treatment: 1-month to 24-month endoscopic follow-up.

OBJECTIVE: Describe the results of a 1- to 24-month follow-up of individuals undergoing transbronchoscopic placement of one-way valves. DESIGN: Longitudinal, noncomparative study. SETTING: University hospital. PATIENTS: Nineteen heterogeneous emphysema patients. MEASUREMENTS AND RESULTS: Pulmonary function testing, imaging examination, and videobronchoscopy were performed at 1, 3, 6, 12, and 24 months after the insertion of one-way valves. Mean age was 67.63 +/- 8.71 years, mean body mass index (BMI) was 24.02 +/- 2.65, and mean exposure to smoking was 65.32 +/- 27.46 pack-years (+/- SD). Baseline BODE index (BMI, degree of airflow obstruction and dyspnea, exercise capacity as measured by the 6-min walk test [6MWT]) was 7 to 10 in 10 patients (estimated 4-year mortality, 80%) and 5 to 6 in 9 patients (estimated 4-year mortality, 40%). Sixty-four valves were inserted. There was no procedure-related mortality. Nonsustained atelectasis was observed within 48 h in 2 of 12 patients with right upper lobe occlusion. Fifty-six bronchoscopic examinations were performed in 24 months. Granulomas not requiring treatment were the main complication. Mucus clogging the valve, mainly at 1 month, was easily cleaned. Eighteen patients completed the 1- and 3-month follow-ups, 14 patients completed the 6-month follow-up, 11 patients completed the 12-month follow-up, and 5 patients completed the 24-month follow-up. Improvement was observed in the 6MWT after 1 month (p = 0.028) and in the BODE index at 3 months (p = 0.002). FEV1 or FVC improvement > or = 12% or > or = 150 mL was observed, respectively, in 4 of 18 patients and 8 of 18 patients at 1 month, 4 of 18 patients and 7 of 18 patients at 3 months, and in 3 of 14 patients and 5 of 14 patients at 6 months. After 24 months, one of five patients and three of five patients, respectively, retained an FEV1 and FVC change > or = 12% or > or = 150 mL. Significant improvement (decrease > or = 4%) in the St. George Respiratory Questionnaire was observed at 3 months and 6 months in three of four domains. CONCLUSION: Endobronchial valves are safe, but the criteria to measure improvement and to select patients should be refined. Atelectasis should be reconsidered as primary treatment goal.

Rejection and indirect revascularization of glycerin-preserved tracheal implant.

The objective of the following study was to evaluate antigenicity, malacia and revascularization in glycerin-preserved canine tracheal allografts. Trachea with six cartilage rings (2.4 to 3.1 cm) were distributed in three study groups: autograft (21), allograft (18) and glycerin-preserved (22). We implanted two segments from different groups in the greater omentum of dogs. After 28 days, latex was injected in the canine aorta before the segments were harvested. We evaluated number of sectors with functional vessels, number of vessels dyed in the submucosa, acute arteritis score, incidence of acute rejection, cartilage lesion score, and malacia. The autograft group had a larger number of dyed vessels than the glycerin-preserved group. The autograft group also had a higher average number of quadrants with functional vessels than the allograft group and the glycerin-preserved group. The allograft group had a higher mean score for acute arteritis than the autograft group and more acute rejection than the glycerin-preserved group. The cartilage lesion score did not show any significant difference between groups. Malacia was not observed in any tracheal segment. Overall, the glycerin-preserved tracheal implant had low antigenicity and good rigidity, but showed incomplete revascularization.

Experimental model of tracheal stenosis with submucosal resection of cartilaginous rings combined with sodium hydroxide instillations.

OBJECTIVE: To experimentally develop tracheal stenosis and malacia to test new models of tracheal stents. METHODS: We resected three cartilaginous rings from the cervical trachea of dogs in group A (n = 5) and six rings in group B (n = 4) to produce malacia. The mucosa of the region with malacia then received applications of a solution of sodium hydroxide (NaOH) at 23%, and the animals were accompanied with bronchoscopic examinations to observe the development of luminal narrowing of the airway. When the stenosis was of more than 50% or there were minimal signs of ventilatory failure, the animals were sacrificed. The segment of narrowed airway was then collected for histological analysis and calculation of the area of residual lumen in the tracheal segment with stenosis and malacia. RESULTS: In histological analysis, fibrosis was found in the submucosa and adventitia, associated with granulomas in the mucosa. The average residual lumen of the segments with stenosis was 9% and 12% in groups A and B, respectively (p> 0.05). CONCLUSION: The combination of resection of the cartilaginous rings and the application of 23% NaOH in the respiratory mucosa promoted severe tracheal stenosis, but was associated with loss of animals. Further studies are needed to verify that the isolated use of one of the techniques would be safer and more effective to develop tracheal stenosis.

Novel silicone stent to treat tracheobronchial lesions: results of 35 patients.

We describe a case series of 35 patients with either benign (14) or malignant (21) tracheal stenosis who were treated using a novel silicone stent, the HCPA-1, designed to prevent migration. Between March 2001 and September 2008, 13 women and 22 men received 41 HCPA-1 stents. The median duration of stenting in benign cases was 457 days (range, 4-2,961 days). Successful stent removal with curative results was accomplished in 2 patients with tracheomalacia and 1 with post-intubation stenosis. In malignant cases, the median duration of stenting was 162 days (range, 1-1,279 days). Five patients had tumor progression with obstruction requiring repeated laser resection, dilatation, or additional stents. Two patients died due to airway obstruction despite bronchoscopic intervention. Twelve patients with malignant lesions died with the stent in place. At the end of the study, 3 patients with malignant disease remained alive; 2 were lost to follow-up. The HCPA-1 stent proved to be safe, with no severe complications during the study period, and effective in improving quality of life with relief of dyspnea.

Development of different degrees of elastase-induced emphysema in mice: a randomized controlled experimental study

Introduction: Mouse models of emphysema are important tools for testing different therapeutic strategies. The aim of this study was to develop a mouse model of emphysema induced by different doses of elastase in order to produce different degrees of severity. Methods: Thirty female mice (C57BL/6) were used in this study. Different doses of porcine pancreatic elastase were administered intratracheally once a week for four weeks, as follows: 0.1 U (n=8), 0.15 U (n=7), and 0.2 U (n=7). Control mice (n=8) received 50 microL of sterile saline solution intratracheally. Lung mechanics were analyzed by plethysmography. Mean linear intercept and volume fraction occupied by collagen and elastic fibers were determined. Results: An increase in lung resistance was observed with 0.2 U of elastase [median (P-25-P75): 2.02 (1.67; 2.34) cmH2O.s/mL], as well as a decrease in tidal volume and minute ventilation. Peak expiratory flow increased significantly in the groups treated with 0.15 U and 0.2 U of elastase. Mean linear intercept was higher with 0.15 U and 0.2 U of elastase, with destruction of alveolar walls [median (P-25-P75): 30.31 (26.65-43.13) microm and 49.49 (31.67-57.71) microm respectively]. The volume fraction occupied by collagen and elastic fibers was lower in the group receiving 0.2 U of elastase. Conclusion: Four intratracheal instillations of 0.2 U of elastase once a week induced changes in lung function and histology, producing an experimental model of severe pulmonary emphysema, whereas 0.15 U resulted in only histological changes.

Tratamento endoscópico do Enfisema: uma atualização / Bronchoscopic Treatment of Emphysema: an Update

O objetivo desta revisão foi apresentar uma atualização das alternativas endoscópicas utilizadas no tratamento do enfisema pulmonar. Os mecanismos bloqueadores de fluxo (válvulas) permanecem como os únicos dispositivos aprovados para uso clínico no tratamento do enfisema pulmonar na América do Sul. A válvula endobrônquica Zephyr® representa o método broncoscópico para o tratamento do enfisema mais bem estudado até o momento, e seu uso clínico está autorizado em diversos países da Europa, Ásia e América do Sul. A válvula IBV® obteve aprovação para uso no tratamento de fuga aérea prolongada nos EUA. Os critérios mais frequentemente analisados na indicação de tratamento endoscópico, além dos aspectos clínicos, incluem o aprisionamento dinâmico, a heterogeneidade e a ventilação colateral, em especial, a passagem de ar através das cissuras interlobares. Atualmente, há softwares que permitem a medida precisa da heterogeneidade e da integridade da cissura.Os resultados obtidos em diversas séries de casos e alguns ensaios randomizados têm trazido nova luz ao entendimento da fisiopatologia dessa doença. No entanto, ainda há necessidade de mais estudos randomizados utilizando o conhecimento adquirido até o momento

The objective of this review is to present an update on endoscopic alternatives for the treatment of emphysema.One-way endobronchial valves continue to be the only devices approved for clinical use in the treatment of emphysema inSouth America. The use of the Zephyr® endobronchial valve is currently the most widely studied bronchoscopic method fortreatment of emphysema and has been approved for clinical use in several countries in Europe, Asia, and South America. Another valve, the IBV® valve, has been approved for use in the treatment of persistent air leaks in the United States. In additionto clinical features, the criteria most often analyzed for indicating endoscopic treatment are dynamic hyperinflation, heterogeneity, and collateral ventilation, especially the passage of air through the interlobar fissures. Currently, there is softwarecapable of accurately measuring heterogeneity and fissure integrity.The results obtained in various case series and certain randomized trials have shed new light on the pathophysiology of emphysema. However, additional randomized trials using the knowledge gained thus far are warranted in order to furtherevaluate this procedure

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.

[Development of a modified Dumon stent for tracheal applications: an experimental study in dogs]. / Desenvolvimento de uma órtese de Dumon modificada para aplicações traqueais: um estudo experimental em cães.

OBJECTIVE: To describe the development of a silicone stent and perform in vivo testing for biocompatibility/applicability in the normal canine trachea. METHODS: Four different densities were tested in order to obtain the silicone prototypes. The pressure required for compression considering a contact area of 1 cm(2), and a 30% reduction in diameter was calculated for each density. The best density was 70-75 Shore A hardness. Powdered barium sulfate was added to the silicone to make the stent radiopaque and easily identifiable in radiological imaging. This novel stent presents a corrugated external surface with discontinuous and protruding arcs resembling the tracheobronchial rings (for intercalation and fixation in the lumen of the lower airways), a highly polished inner surface and smooth extremities (to prevent friction-related damage). The prototype considered most appropriate in terms of rigidity and flexibility was bronchoscopically implanted in normal canine tracheas. After eight weeks, the animals were euthanized, and the tracheas were removed for anatomopathological analysis. RESULTS: There were no postimplantation complications, and none had to be removed. After eight weeks, the devices were found to be well-positioned. Histopathology revealed a well-preserved epithelial basal membrane, foci of denuded epithelium, mild submucosal inflammatory infiltrate with scattered granulation tissue, vascular neoformation, and no microorganisms. CONCLUSIONS: The stent developed proved resistant to mechanical stress, biocompatible in the canine trachea and well-preserved at the study endpoint.

Tratamento endoscópico do enfisema / Bronchoscopic treatment of emphysema

O objetivo do presente estudo foi apresentar as alternativas endoscópicas para o tratamento do enfisema pulmonar. Os tratamentos incluem o remodelamento com cola biológica e vapor, mecanismos bloqueadores do fluxo aéreo (válvulas) e mecanismos não bloqueadores (coils). A principal diferença entre o remodelamento e os dispositivos (bloqueadores ou não) é que o remodelamento é definitivo, enquanto válvulas e coils podem ser retirados e substituídos. Até o momento, somente válvulas foram aprovadas para uso clínico na América do Sul. Os fatores mais significativos para selecionar pacientes para os diversos tratamentos não cirúrgicos, além dos aspectos clínicos, são o aprisionamento dinâmico, a heterogeneidade e a ventilação colateral. A broncoscopia virtual tem um papel importante no planejamento do tratamento endoscópico do enfisema, diminuindo o tempo do procedimento. Tendo em vista as dúvidas que permanecem acerca dos mecanismos fisiopatológicos de melhora dos pacientes e dos critérios de seleção dos mesmos, é fundamental estabelecer protocolos para o emprego dessas técnicas. Também são necessárias meta-análises para interpretar os resultados já descritos na literatura, assim como estudos randomizados de grande porte que levem em conta os conhecimentos adquiridos até o momento.

The objective of this review is to present endoscopic alternatives for the treatment of emphysema. Treatments include tissue remodeling with biological glue or thermal vapor; airflow blocking mechanisms (valves); and nonblockingmechanisms (coils). The main difference between the remodeling technique and the use of (blocking or non-blocking)devices is that remodeling is definitive, whereas valves and coils can be removed and replaced. In South America, only valve implants have been approved for clinical use. In addition to clinical features, the major criteria for selecting patients for nonsurgical treatment are dynamic hyperinflation, heterogeneity, and collateral ventilation. Virtual bronchoscopy, which reduces the procedure time, plays an important role in the planning of endoscopic treatment for emphysema. Questions remain regarding patient selection criteria and the pathophysiological mechanisms leading to improvement. It is therefore essential to establish guidelines for the use of this technology. Meta-analyses interpreting the results described inthe literature, as well as large randomized trials of the various techniques, should also be conducted to further evaluate this procedure.

Tratamento endoscopico das estenoses funcionais das vias aereas / Bronchoscopic management of functional airway obstruction

O objetivo do presente estudo foi caracterizar a traqueobroncomalacia (TBM) e excessive dynamic airway collapse (EDAC, colapso dinâmico excessivo das vias aereas). Embora a TBM e o EDAC, caracterizados por uma redução de 50% ou mais da luz, sejam descritos com frequencia crescente na forma de relatos de casos clinicos, faltam dados sistematizados que permitam o pronto diagnostico e a distinção entre TBM e EDAC. As tecnicas endoscopicas tem papel fundamental no diagnostico e podem ser uma alternativa para o tratamento de TBM e EDAC. É evidente a necessidade de estudos mais aprofundados acerca de TBM e EDAC que permitam o pronto reconhecimento e o tratamento adequado dessas entidades e das doenças subjacentes, contribuindo para uma melhora na qualidade de vida dos pacientes.

The objective of this review was to characterize tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC). There have been clinical case reports of TBM and EDAC, both of which are characterized by a ¡Ý 50% reduction in the crosssectional area of the tracheobronchial lumen, and the number of such reports is increasing. However, there are no systematicdata that would facilitate prompt diagnosis and allow distinctions to be drawn between TBM and EDAC. Endoscopic techniques play a key role in the diagnosis of both conditions and might represent an alternative means of treating patients with TBM or EDAC.There is a clear need for further studies of TBM and EDAC in order to develop strategies for the prompt recognition andproper treatment of these entities, as well as of the underlying diseases. The use of such strategies could lead to an improvement in the quality of life of patients within this population.

Transplante pulmonar na fibrose cística / Lung transplantation in cystic fibrosis

A progressão do acometimento pulmonar e a evolução para insuficiência respiratória são responsáveis por importante morbimortalidade em pacientes com fibrose cística. O transplante pulmonar está consolidado como tratamento de escolha para diversas pneumopatias em estágios terminais e vem sendo realizado em pacientes com fibrose cística avançada desde a década de 1980. A seleção de pacientes candidatos ao transplante envolve a análise cuidadosa de parâmetros clínicos,fisiológicos e laboratoriais, com atenção a fatores conhecidos de mau prognóstico como: piora acentuada e acelerada dafunção pulmonar, aumento da frequência e gravidade das exacerbações, desnutrição, diabetes melito, hemoptise volumosa,pneumotórax, hipoxemia e hipercapnia em ar ambiente, hipertensão pulmonar e distância reduzida no teste de caminhada de seis minutos. Embora o tema ainda gere controvérsias, a maioria dos centros transplantadores contraindica o transplantepara portadores de Burkholdelia cepacia. A presença de outros germes colonizantes no escarro, ainda que com perfil adverso de sensibilidade aos antibióticos, não costuma impedir a realização do transplante em pacientes com fibrose cística. A avaliação pré-transplante nesta população segue os mesmos padrões das demais indicações, com atenção especial ao suporte nutricional, ao perfil microbiológico e à evolução recente do contexto clínico global e da função pulmonar. Os resultados do transplante pulmonar bilateral na fibrose cística são em regra superiores aos das demais indicações.

Progressive involvement of the lungs and the development of respiratory failure are major causes of morbidity and mortalityin patients with cystic fibrosis. Lung transplantation is a well-established treatment for several end-stage respiratory diseases and it has been successfully performed in cystic fibrosis patients since the 1980’s. Patient selection involves careful analysisof clinical, physiologic and laboratorial parameters, with special consideration of well-known adverse prognostic factors suchas: accelerated loss of lung function, increase in frequency and severity of exacerbations, poor nutritional status, diabetes mellitus, massive hemoptysis, pneumothorax, hypoxemia and hypercapnia while breathing room air, pulmonary hypertension,and reduced distance in the 6-minute walk test. Despite some controversy, most transplant centers refuse patients with Burkholderia cepacia for transplantation. Other colonizing pathogens, even with extensive antibiotic resistant patterns, donot, in general, preclude the procedure in patients with cystic fibrosis. Pre-transplant evaluation of this population is similarfor other indications, with special attention to nutritional support, microbiological profile analysis and recent changes of theclinical context and lung function. The results of bilateral lung transplantation for cystic fibrosis are generally better than forother indications.

Modelo experimental de estenose traqueal mediante ressecção cirúrgica submucosa de anéis traqueais combinada com instilações de hidróxido de sódio / Experimental model of tracheal stenosis with submucosal resection of cartilaginous rings combined with sodium hydroxide instillations

OBJETIVO: Desenvolver, experimentalmente, malácia e estenose traqueal para testar novos modelos de órteses traqueais. MÉTODOS: Ressecamos três anéis cartilaginosos da traqueia cervical de cães no grupo A (n=5) e seis anéis no grupo B (n=4) para produzir malácia. Logo após, a mucosa da região com malácia recebeu aplicações de uma solução de hidróxido de sódio (NaOH) a 23 por cento, e os animais eram acompanhados com exames broncoscópicos para observar o desenvolvimento de estreitamento da luz da via aérea. Quando a estenose era de mais de 50 por cento da luz, ou havia sinais mínimos de insuficiência ventilatória, os animais eram sacrificados. O segmento de via aérea estreitada foi então coletado para análise histológica e era calculada a área de luz residual do segmento traqueal com estenose e malácia. RESULTADOS: Na análise histológica, foi constatada fibrose na submucosa e adventícia, associada a granulomas na mucosa. A luz residual média dos segmentos com estenose foi de 9 por cento e 12 por cento nos grupos A e B, respectivamente, (p>0,05). CONCLUSÃO: A combinação da ressecção de anéis cartilaginosos e da aplicação de NaOH 23 por cento na mucosa respiratória promoveu uma estenose traqueal intensa, porém esteve associada à perda de animais. Novos estudos são necessários para verificar se o emprego isolado de uma das técnicas seria mais seguro e eficaz para desenvolver estenose traqueal.

OBJECTIVE: To experimentally develop tracheal stenosis and malacia to test new models of tracheal stents. METHODS: We resected three cartilaginous rings from the cervical trachea of dogs in group A (n = 5) and six rings in group B (n = 4) to produce malacia. The mucosa of the region with malacia then received applications of a solution of sodium hydroxide (NaOH) at 23 percent, and the animals were accompanied with bronchoscopic examinations to observe the development of luminal narrowing of the airway. When the stenosis was of more than 50 percent or there were minimal signs of ventilatory failure, the animals were sacrificed. The segment of narrowed airway was then collected for histological analysis and calculation of the area of residual lumen in the tracheal segment with stenosis and malacia. RESULTS: In histological analysis, fibrosis was found in the submucosa and adventitia, associated with granulomas in the mucosa. The average residual lumen of the segments with stenosis was 9 percent and 12 percent in groups A and B, respectively (p> 0.05). CONCLUSION: The combination of resection of the cartilaginous rings and the application of 23 percent NaOH in the respiratory mucosa promoted severe tracheal stenosis, but was associated with loss of animals. Further studies are needed to verify that the isolated use of one of the techniques would be safer and more effective to develop tracheal stenosis.

Liga com memória de forma: estudo preliminar do grampo de judet de nitinol e sua possível aplicação em tórax instável / Shape memory alloy: a preliminary study of nitinol judet staples for future application in flail chest

Este artigo sucintamente descreve a evolução da liga metálica “inteligente”, com memória de forma na área de Saúde. A confecção de grampos de Judet em nitinol ocorreu no Laboratório de Transformação Mecânica da UFRGS (LdTM) e a simples verificação das qualidades superelásticas e de memória de forma foram contempladas no LdTM e no HCPA pela equipe envolvida no projeto. A título de ilustração, demonstramos com um caso clínico a aplicabilidade do grampo de Judet no cenário de instabilidade da parede torácica, a qual, além de prejudicar a mecânica respiratória, apresenta uma alta taxa de mortalidade. Os resultados preliminares evidenciaram a transformação provocada pelo calor, ocasionando o fechamento das garras dos grampos de Judet, que se manteve firme e sem alteração da consistência com o tempo, permitindo antever sua aplicabilidade num modelo experimental. Grampos de Judet em Nitinol são apresentados teoricamente como vantajosos em relação aos já existentes em aço inoxidável 316L, especialmente pela facilidade de manuseio e possível simplificação do procedimento cirúrgico. Detalhes no acabamento permitem a biocompatibilidade e o engenheiro projetista de materiais deve compatibilizar as ligas de níquel e titânio (NiTi) utilizadas nos grampos. O nitinol possui amplo emprego no cenário médico-odontológico e há normas técnicas bem definidas. A epidemiologia do trauma e a gravidade das lesões associadas à instabilidade da parede torácica evidenciam a oportunidade de estudos nessa direção. Concluímos sobre a necessidade de prosseguir para uma avaliação experimental, agregando a mensuração de parâmetros viscosos e viscoelásticos da mecânica respiratória, especialmente em seu componente de parede torácica (cw).

The aim of this article is to briefly describe the incorporation of nitinol (NiTi) – an intelligent nickel-titanium alloy presenting shape memory – for use in medical applications. Nitinol Judet staples were developed at the Mechanical Processing Laboratory (LdTM) at Universidade Federal do Rio Grande do Sul. Simple confirmation assays of superelasticity and shape memory were performed at the LdTM and Hospital de Clínicas de Porto Alegre by the project team. A clinical case was used to demonstrate the applicability of nitinol Judet staples in the treatment of flail chest, a condition characterized by respiratory mechanics associated with fairly high mortality. The initial observation revealed a transformation resulting from heat exposure causing the closure of staple prongs. With time, the consistency of the Judet staples remained unchanged, indicating the feasibility of an experimental model employing these staples. The advantages of NiTi-made Judet staples in relation to 316L stainless steel staples are outlined, with emphasis on the ease of use and possible simplification of the surgical procedure. Finishing details ensure biocompatibility, with a focus on specific adaptations in the NiTi alloy employed to manufacture the staples; nevertheless, nitinol is widely employed in medicine and dentistry, with well-defined standards. The epidemiology of trauma and the severity of lesions associated with flail chest provide an opportunity for the proposed studies. The experimental assessment of nitinol Judet staples must now address viscosity and viscoelastic parameters of respiratory mechanics, especially concerning the chest wall.

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.