Stent placed by endoscopy for the treatment of tracheal obstruction caused by a tumor in a domestic cat

Background: Tracheal tumors are rare and may cause obstruction of the trachea. The neoplasms most commonly diagnosed in cats are lymphosarcoma, squamous cell carcinomas and adenocarcinomas. Surgical resection may provide a clinical cure for small, benign and localized tumors. For malignant neoplasia, surgery is usually palliative. Tracheal segment excision is an invasive procedure, particularly when the intrathoracic trachea is involved, and this increases the risk of stenosis, surgical suture dehiscence, necrosis and pneumothorax. Intraluminal tracheal stents have been used in dogs with tracheobronchomalacia, presenting a feasible alternative to surgery for the treatment of tracheal lumen obstruction. Case: A 11-year-old male mixed-breed cat was referred to the Veterinary Hospital of the Federal University of Rio Grande do Sul (HCV-UFRGS) with a history of appetite loss, wasting and progressive inspiratory dyspnea, for the last 30 days. The cat presenting with oral breathing. Radiography of the lateral thorax shown a radiopaque area, 1cm in diameter, superimposed in the tracheal region, close to the carina cartilage, at the fourth intercostal space. A tracheoscopy confirmed the diagnosis of tracheal neoplasia, which was identified as an adenocarcinoma by biopsy and histopathology. Given that surgical resection may result in significant morbidity and consequent mortality, the owner chose a palliative treatment without adjuvant therapy for adenocarcinoma until acquisition of the stent, with partial resection of the tumor performed during tracheoscopy. This procedure was performed twice at an interval of three months. After the first endoscopic examination, the patient regained weight and normal behavior. Three months after the second tracheoscopy, signs of labored breathing recurred. At this point, the obstruction was treated with implantation of an intratracheal stent. A nitinol biliary stent, 35 mm in length, 8 mm in diameter, was applied during tracheoscopy without fluoroscopy aid. The cat received postoperative treatment with dexamethasone 0.25 mg.kg­¹ SID for seven days. The patient showed immediate clinical improvement in dyspnea, but retained an episodic cough. After six months, the cat suffered a relapse of dyspnea. Radiographic examination revealed a large area of radiopacity in the region of the tracheal stent, suggesting an increase in size of the tumor, and possible metastasis in the lung parenchyma. The patient underwent repeat tracheoscopy, and almost complete obstruction of the tracheal lumen was found. The cat died during this procedure. Post-mortem examination was requested, which confirmed tracheal obstruction resulting from growth of the tumor, and pulmonary metastasis. Discussion: There are few reports of tracheal neoplasms in cats, because they are uncommon. The diagnosis was based on radiography, tracheoscopy and incisional biopsy. Treatment with surgery involves high morbidity and mortality. For this reason we chose the use of a tracheal stent, although palliative in cases of cancer. Stents are frequently used in humans with malignant tracheal obstruction, but the few reports in the veterinary literature, are focused on dogs presenting with tracheobronchomalacia. In cats, a few cases of tracheal stenosis and tumors have been treated experimentally with stents, which have shown success in reestablishing an airway. In previous reports, the technique has always been carried out with the aid of fluoroscopy. The application of the stent using tracheoscopy alone was efficient. The patient in this report suvived for one year since it diagnosed before near-total obstruction of the trachea occurred. Therefore this was a palliative measure, which allowed the patient a good quality of life while receiving adjuvant therapy when possible or necessary.

Microplacas de titânio em fraturas de tibiotarso em pombos domésticos / Titanium microplates for treatment of tibiotarsus fractures in pigeons

Entre os problemas cirúrgicos das aves, as fraturas são os de maior prevalência. Em virtude das variações no tamanho, peso, anatomia óssea peculiar, alta incidência de fraturas complicadas e das diferentes demandas funcionais entre espécies e indivíduos, não foi possível estabelecer ainda um método ideal de osteossíntese para os ossos longos das aves. Microplacas de titânio comumente utilizadas em cirurgias maxilofaciais de humanos foram empregadas recentemente na osteossíntese de aves, porém com poucos resultados disponíveis. O objetivo do presente estudo foi avaliar a utilização das microplacas de titânio no tratamento de fraturas experimentais de tibiotarso em pombos domésticos (Columba livia). Foram utilizadas 30 aves adultas, machos e fêmeas, com 7 meses de idade, pesando entre 400 a 500 gramas. Os animais foram separados em três grupos de dez, sendo que no grupo 1 foi utilizado uma microplaca de titânio com 6 furos e espaçador central; no grupo 2, com oito furos sem espaçador central; e, no grupo 3, com oito furos com espaçador central. Após avaliação clínica, as aves foram submetidas à osteotomia médio-diafisária no tibiotarso direito para colocação das diferentes configurações de microplaca de titânio, sendo fixadas com microparafusos de titânio com 7mm de comprimento. Os animais foram avaliados clínica e radiograficamente até os 90 dias de pós-operatório. Após esse período, foi realizada eutanásia em duas aves de cada grupo. Em todas elas, foi observada a consolidação óssea, sendo que, no grupo 1, o tempo médio e o desvio padrão foram 32,9±9,9; no grupo 2, 30,8±6,7 e, no grupo 3, 26,6±6,4 dias, não havendo diferença estatística entre os grupos. O envergamento do implante foi a complicação mais frequente. A configuração da microplaca resultou em diferença estatisticamente significativa em relação à deambulação e ao grau de envergamento nos diferentes grupos, sendo que, no grupo 3, houve maior precocidade no apoio do membro e menor grau de envergamento em relação aos outros grupos. Histologicamente, foi verificada a formação de calo ósseo em todos os animais e presença de tecido ósseo ao redor da microplaca e dos microparafusos. Apesar das complicações observadas, as microplacas de titânio são uma opção para osteossíntese de tibiotarso em aves de médio porte.

Among the surgical problems in birds, the fractures are the most prevalent. Due to variations in size, weight, peculiar bone anatomy, high incidence of complicated fractures and functional demands of different species and individuals, it is still not possible to establish an ideal method for osteosynthesis of long bones in birds. Titanium microplates commonly used in human maxillofacial surgery have been recently employed in osteosynthesis of birds, but with few results available. The aim of this study was to evaluate the use of titanium microplates in the treatment of tibiotarsus fractures in 30 pigeons (Columba livia) , adult males and females, with 7 months old, weighing from 400 to 500. The animals were divided into 3 groups with ten animals each. In group 1, a titanium microplate with 6 holes and a central spacer was used; in group 2, a titanium microplate with 8 holes without a spacer in the center was used; in group 3, a titanium microplate with 8 holes with central spacer was used. After clinical evaluation, the birds were submitted to mid-diaphyseal osteotomy in the right bone for placement of different configurations of the titanium plate, and fixed with titanium microscrews 7mm long. The animals were evaluated clinically and radiographically until 90 days postoperatively. After this period, euthanasia was performed in 2 animals from each group. In all animals was observed bone healing and in group 1 the mean and standard deviation were 32.9±9.9 days, in group 2, 30.8±6.7 days in group 3, 26.6±6.4 days. There was no statistical difference in healing time between groups. The bending of the implant was the most common complication. The configuration of the plate resulted in a statistically significant difference in relation to walking and to the degree of bending in the different groups. Moreover, in group 3 there was higher precocity in the member suppor and a lower degree of bending in relation to other groups. Histologically, it was verified formation of the callus in all animals and presence of bone tissue around the plate and microscrews. Despite the complications of titanium microplates, they are an option for tibiotarsus osteosynthesis in birds of medium size.