In vivo performance of decellularized tracheal grafts in the reconstruction of long length tracheal defects: Experimental study.

BACKGROUND: The repair of long-segment tracheal lesions remains an important challenge. Nowdays no predictable and dependable substitute has been found. Decellularized tracheal scaffolds have shown to be a promising graft for tracheal transplantation, since it is non-immunogenic. OBJECTIVE: Evaluate in vivo decellularized tracheal allografts performance to replace long tracheal segment. METHODS: Forty-five swines underwent surgery as follows: Fifteen trachea donors and 30 receptors of decellularized trachea allografts. The receptors were randomly divided in five groups (n = 6). In groups I and II, donor trachea segment was decellularized by 15 cycles with sodium deoxycholate and deoxyribonuclease, in group II, the allograft was reinforced with external surgical steel wire. Groups, III, IV, and V decellularization was reduced to seven cycles, supplemented with cryopreservation in group IV and with glutaraldehyde in group V. A 10 rings segment was excised from the receptor swine and the decellularized trachea graft was implanted to re-establish trachea continuity. RESULTS: Both decellularization cycles caused decreased stiffness. All trachea receptors underwent euthanasia before the third post-implant week due to severe dyspnea and trachea graft stenosis, necrosis, edema, inflammation, hemorrhage, and granulation tissue formation in anastomotic sites. Histologically all showed total loss of epithelium, separation of collagen fibers, and alterations in staining. CONCLUSIONS: Both decellularization techniques severely damaged the structure of the trachea and the extracellular matrix of the cartilage, resulting in a no functional graft, in spite of the use of surgical wire, cryopreservation or glutaraldehyde treatment. An important drawback was the formation of fibrotic stenosis in both anastomosis.

Experimental Tracheal Replacement: Angiogenesis and Null Apoptosis Promote Stenosis.

BACKGROUND: Tracheal replacement is a challenge for thoracic surgeons due to stenosis in the trachea-prosthesis anastomosis. We propose that stenosis occurs due to fibrosis as a result of an abnormal healing process, characterized by an increased expression of wound healing growth factors (vascular endothelial growth factor [VEGF], survivin, and CD31), which promote angiogenesis and decrease apoptosis. We analyzed the immunoreactivity of VEGF, survivin, CD31, and caspase-3 in the development of fibrotic stenosis in prosthetic tracheal replacement. METHODS: Fourteen dogs were operated on: group I (n=7) received a 6-ring cervical tracheal segment autograft, while in group II (n=7), a 6-ring segment of the cervical trachea was resected and tracheal continuity was restored with a Dacron prosthesis. The follow-up was 3 months. Immunoreactivity studies for VEGF, survivin, CD31, and caspase-3 were performed. A statistical analysis was done using the Wilcoxon signed rank test. RESULTS: Four animals in group I were euthanized on the 10th postoperative day due to autograft necrosis. Three animals completed the study without anastomotic stenosis. Moderate expression of VEGF (p=0.038), survivin (p=0.038), and CD31 (p=0.038) was found. All group II animals developed stenosis in the trachea-prosthesis anastomotic sites. Microscopy showed abundant collagen and neovascularization vessels. Statistically significant immunoreactive expression of VEGF (p=0.015), survivin (p=0.017), and CD31 (p=0.011) was observed. No expression of caspase-3 was found. CONCLUSION: We found a strong correlation between fibrosis in trachea-prosthesis anastomoses and excessive angiogenesis, moderate to intense VEGF, CD31, and survivin expression, and null apoptotic activity. These factors led to uncontrolled collagen production.

Fast cyclical-decellularized trachea as a natural 3D scaffold for organ engineering.

Commonly reported decellularization protocols for trachea may take up from several weeks to months in order to remove the cellular materials. Two years ago, we significantly reduced the time of decellularization trachea process using trypsin. Despite the positive outcome, the protocol was useful to produce 5 cm graft length, an unsuitable length graft for most patients with tracheal disorders. In this work we improved the decellularization procedure for longer sections up to 10 cm without considerable extension in the necessary time process (2 weeks). Herein, for the first time, we completely describe and characterize the process for pig tracheal bioactive scaffolds. Histological and molecular biology analysis demonstrated effective removal of cellular components and nuclear material, which was also confirmed by the Immunohistochemical (IHC) analysis of the major histocompatibility complexes (MHCs) and DNA stain by 4'-6-diamidino-2-phenylindole (DAPI). The images and data obtained from scanning electron microscopy (SEM) and thermal analysis showed conservation of the hierarchical structures of the tracheal extracellular matrix (ECM), the biomechanical tests showed that decellularization approach did not lead to a significant alteration on the mechanical properties. In this paper, we demonstrate that the proposed cyclical-decellularization protocol allowed us to obtain a non-immunological 10 cm natural tracheal scaffold according to the in vivo immunological assessment. Furthermore, the recellularization of the matrix was successfully achieved by demonstrating first-stage cellular differentiation from stem cells to chondrocytes expressed by the SOX9 transcription factor; this organ-engineered tracheal matrix has the potential to act as a suitable template for organ regeneration.

Lung necrosectomy in pediatric patients with necrotizing pneumonia.

INTRODUCTION: Necrotizing pneumonia is the consolidation of lung parenchyma with destruction and necrosis, forming solitary or multiloculated radiolucent foci. When antibiotic treatment fails and clinical course does not improve, patients might need lung tissue resection: segmentectomy, lobectomy or bilobectomy. We have performed a more conservative surgical approach in pediatric patients with necrotizing pneumonia, lung necrosectomy: resection of unviable necrotic tissue, to preserve more healthy and potentially recoverable lung parenchyma. The objective of this study is to present the results of our experience with lung necrosectomy. METHODS: Retrospective review of clinical charts of children with necrotizing pneumonia. The diagnosis was based on physical examination, laboratory data and contrast CT scan. Lung necrosectomy technique includes resection of necrotic tissue with careful debridement technique; air leaks were sutured and/or tissue imbrication. RESULTS: Twenty-four children were surgically treated for necrotizing pneumonia (18 girls and 6 boys). The mean age was 31.5 ± 13.5 months. All the patients presented productive cough, fever and dyspnea; chest X-rays showed consolidated areas with intraparenchymal cavities and hypoperfusion on the contrasted CT. Surgical treatment included: Lung necrosectomy 17 (70%); lobectomy 3 (12.5%); wedge resection 2 (8.3%); lobectomy + lung necrosectomy 1 (4.1%), and wedge resection + lung necrosectomy 1 (4.1%). The postoperative course was uneventful in 23 patients; mean postoperative hospital stay was 6.3. One patient died because of sepsis. CONCLUSIONS: Lung necrosectomy is a conservative, effective surgical treatment, which solves lung necrotizing infection avoiding resection of healthy lung parenchyma.

Surgical Skills Training with Cryopreserved Rat Stomachs.

The objective of this study is to present a high-fidelity bench model of cryopreserved stomachs that can be used while learning surgical skills. Thirty stomachs were harvested from Wistar rats at the end of non-abdominal research studies. The stomachs were washed with cold saline solution and filled with hyaluronic acid solution. The organs were then placed into cryovials and cryopreserved at -30 °C for 60 days. The stomachs were thawed to room temperature on the day of the surgical skills practice and two full-thickness incisions were made. Reporting on their experiences, 22 participants (73.33%) felt that the cryopreserved stomach was identical to in vivo rat stomachs, 24 (80.00%) reported that the stomach was easy to handle, and 27 (90%) reported the tissue was non-friable. Moreover, 29 participants (96.6%) finished the suturing without tears and 100% recommended it as a biomaterial for surgical training. The cryopreserved stomach is a practical, reproducible, low-cost, and high-fidelity bench model that allows surgical fellows to learn how to handle a stomach and improve their surgical abilities before performing surgery on patients or laboratory animals.

Comparison of lyophilized glutaraldehyde-preserved bovine pericardium with different vascular prostheses for use as vocal cords implants: experimental study.

This study compared the use of lyophilized glutaraldehyde-preserved bovine pericardium (LGPBP), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and Teflon felt (TF) as implants for vocal cords (VC) medialization and aimed to assess the endoscopic, macroscopic, and microscopic VC changes after medialization in a canine model. In 18 mongrel dogs, the right VC were medialized with LGPBP and the left were implanted as follows: Group I (n = 6): LGPBP and PTFE; Group II (n = 6): LGPBP and PET; Group III (n = 6): LGPBP and TF. Surgical handling of the implants was compared. Three months after surgery, macroscopic and microscopic changes of VC and implants were evaluated. LGPBP offered the best surgical handling (p = 0.005, Kruskal-Wallis). TF implants showed extrusion (p = 0.005, Kruskal-Wallis) and severe inflammation. All VC formed fibrous capsules around the implants; the ones developed by LGPBP implants were thinner (p = 0.001, ANOVA, Tukey). VC implanted with synthetic materials showed eosinophilic infiltration (p = 0.01, Kruskal-Wallis). We concluded that the LGPBP could be used as an implant for VC medialization because it is biocompatible, easy to handle and remove during surgical procedures, and nonabsorbable or extrudable and produces an inflammatory reaction similar to PTFE and PET.

Bench surgical training with lyophilized esophageal segments

PURPOSE: To present lyophilized esophageal segments that can be used to learn surgical skills. METHODS: Four esophagus were harvested from four non-esophagus related research dogs at the moment of euthanasia. Each esophagus was trimmed in 3 cm long segments. They were lyophilized and stored during 30 days. The day programmed for surgical skills practice, they were rehydrated. RESULTS: Sixteen segments have been used. After rehydrating, all the segments kept their normal anatomic shape and structural integrity. One incision was made on every esophageal segment and sutured with running stitches of 3-0 polyglactin 910. There were no complications, such as tissue tears, nor esophageal hardening. CONCLUSIONS: The lyophilized esophagus is a high fidelity, practical, reproducible, portable, low-cost bench model. It allows general surgery apprentices to learn how to handle an esophagus, as well as to perfect their surgical and suture abilities before applying them on real patient's esophagus.

Bench surgical training with lyophilized esophageal segments.

PURPOSE: To present lyophilized esophageal segments that can be used to learn surgical skills. METHODS: Four esophagus were harvested from four non-esophagus related research dogs at the moment of euthanasia. Each esophagus was trimmed in 3 cm long segments. They were lyophilized and stored during 30 days. The day programmed for surgical skills practice, they were rehydrated. RESULTS: Sixteen segments have been used. After rehydrating, all the segments kept their normal anatomic shape and structural integrity. One incision was made on every esophageal segment and sutured with running stitches of 3-0 polyglactin 910. There were no complications, such as tissue tears, nor esophageal hardening. CONCLUSIONS: The lyophilized esophagus is a high fidelity, practical, reproducible, portable, low-cost bench model. It allows general surgery apprentices to learn how to handle an esophagus, as well as to perfect their surgical and suture abilities before applying them on real patient's esophagus.

Pericardio bovino tratado con glutaraldehído y liofilizado como materiales para la medialización de cuerdas vocales en modelo animal / Glutaraldehyde-preserved and lyophilized bovine pericardium as materials for medialization of the vocal folds in an animal model

Introducción: El pericardio bovino tratado con glutaraldehído (PBTG) y el pericardio bovino tratado con glutaraldehído liofilizado (PBTGL)ha sido utilizado exitosamente en la reparación de varios defectos anatómicos, pero su eficacia y seguridad como implantes de cuerdas vocales (CV) no se ha descrito. Objetivo: Evaluar la utilidad del PBTG y PBTGL como material para la medialización tiroplástica y valorar los cambios endoscópicos, macroscópicos y microscópicos de las CV posmedialización en un modelo experimental canino. Material y métodos: En 12 perros mestizos, se medializó la CV derecha con pericardio y la izquierda con politetrafluoroetileno (PTFE). Grupo i (n=6): PBTG, y Grupo ii (n=6): PBTGL. Se comparó el manejo quirúrgico de los implantes. Los animales se valoraron clínica y endoscópicamente. Tres meses poscirugía se evaluaron macroscópica y microscópicamente las laringes. Resultados: El PBTG y PBTGL mostraron mejor manejo quirúrgico (Kruskal-Wallis, p=0,005). No se presentaron granulomas, absorción o extrusión del implante en ningún caso endoscópica ni macroscópicamente. Al final del estudio las CV medializadas con PTFE se observaron más engrosadas. Microscópicamente todas las CV formaron una cápsula fibrosa alrededor del implante y una reacción inflamatoria crónica similar, pero las implantadas con PTFE mostraron infiltrado eosinofílico (Kruskal-Wallis, p<0,05). Conclusión: El PBTG y PBTGL pueden ser utilizados para la medialización de las CV debido a que son biocompatibles, de fácil manejo quirúrgico, no se absorben, no migran, ni extruyen y producen una reacción inflamatoria similar a la del PTFE (AU)

Introduction: Glutaraldehyde-preserved bovine pericardium (GBP) and lyophilized GBP (LGBP) have been used successfully in repairing several anatomical defects, but their effectiveness and safety as implants to vocal cords (VC) have not been reported. Objective: The aim of this study was to evaluate the use of GBP and LGBP as materials for medialization thyroplasty, as well as to assess the endoscopic, macroscopic and microscopic VC changes after medialization in an experimental canine model. Material and methods: In 12 healthy mongrel dogs, the right VC were medialized using pericardium and the left with polytetrafluoroethylene (PTFE). Group 1 (n=6): GBP and Group 2 (n=6): LGBP. The surgical manoeuvrability of the implants was compared. The animals were evaluated clinically and endoscopically. Three months after surgery, the larynges were assessed macro- and microscopically. Results: Both GBP and LGBP implants showed better surgical manoeuvrability (Kruskal-Wallis, P=0.005). Endoscopic and macroscopic studies showed no evidence of granulomas, absorption or extrusion of the implant. At the end of the study, greater thickness was observed in VC implanted with PTFE. Microscopically, all the VC developed fibrous capsules surrounding the implants and similar chronic inflammation reaction. The VC implanted with PTFE presented eosinophilic infiltration (Kruskal-Wallis, P<0.05). Conclusion: Both GBP and LGBP can be used as implants for VC medialization because they are biocompatible, have easy surgical manoeuvrability, do not suffer absorption, migration or extrusion and produce inflammation reactions similar to those of PTFE (AU)

Canine tracheal cartilage cryopreservation: freezing injury is not related to caspase-3 expression.

Currently, there are no surgical strategies to treat tracheal lesions longer than 7 cm. Such patients are not candidates for tracheal resection or end-to-end anastomosis and are thus left with only repeated palliative procedures to relieve their respiratory insufficiency. Experimental studies using cryopreserved trachea have produced contradictory results, limiting the clinical application of this technique. We evaluated caspase-3 expression and the histological integrity of canine tracheal cartilage cryopreserved using two different solutions, two temperatures, and varying lengths of storage time. Thirty canine tracheal segments of 5 rings were studied. Group 1: Control without cryopreservation. Groups 2 and 4: Cryopreserved in F12K media with 20% fetal bovine serum (FBS) at -70°C for 48 hours. Groups 3 and 5: Cryopreserved in 90% FBS at -70°C for 48 hours. Groups 4 and 5 were then stored for 15 days in liquid nitrogen. All of the segments were thawed, fixed in wax, and cut into rings. Three rings were selected for caspase-3 expression and histological evaluation. Staining of cartilage matrices was significantly modified in the tracheal segments of Group 5. The central region of the cartilage ring was more vulnerable to the effects of freezing than the edges. Under the same cryopreservation temperature and storage time, tracheal cartilage integrity is better preserved when F12K media is used. Caspase-3 expression is not related to cartilage injury from the cryopreservation process.

[Glutaraldehyde-preserved and lyophilized bovine pericardium as materials for medialization of the vocal folds in an animal model]. / Pericardio bovino tratado con glutaraldehído y liofilizado como materiales para la medialización de cuerdas vocales en modelo animal.

INTRODUCTION: Glutaraldehyde-preserved bovine pericardium (GBP) and lyophilized GBP (LGBP) have been used successfully in repairing several anatomical defects, but their effectiveness and safety as implants to vocal cords (VC) have not been reported. OBJECTIVE: The aim of this study was to evaluate the use of GBP and LGBP as materials for medialization thyroplasty, as well as to assess the endoscopic, macroscopic and microscopic VC changes after medialization in an experimental canine model. MATERIAL AND METHODS: In 12 healthy mongrel dogs, the right VC were medialized using pericardium and the left with polytetrafluoroethylene (PTFE). Group 1 (n=6): GBP and Group 2 (n=6): LGBP. The surgical manoeuvrability of the implants was compared. The animals were evaluated clinically and endoscopically. Three months after surgery, the larynges were assessed macro- and microscopically. RESULTS: Both GBP and LGBP implants showed better surgical manoeuvrability (Kruskal-Wallis, P=.005). Endoscopic and macroscopic studies showed no evidence of granulomas, absorption or extrusion of the implant. At the end of the study, greater thickness was observed in VC implanted with PTFE. Microscopically, all the VC developed fibrous capsules surrounding the implants and similar chronic inflammation reaction. The VC implanted with PTFE presented eosinophilic infiltration (Kruskal-Wallis, P<.05). CONCLUSION: Both GBP and LGBP can be used as implants for VC medialization because they are biocompatible, have easy surgical manoeuvrability, do not suffer absorption, migration or extrusion and produce inflammation reactions similar to those of PTFE.

Cryopreserved tracheal segments: a new tool for bench surgical training in thoracic surgery.

PURPOSE: To present a new low-cost high fidelity bench model of cryopreserved trachea that can be used to learn surgical skills from medical students to cardiothoracic surgery fellows. METHODS: Ten tracheas were harvested from ten non-trachea related research dogs at the moment of euthanasia. Each trachea was trimmed in six or seven rings segments. They were cryopreserved and stored during 60 days. The day programmed for surgical skills practice, they were thawed to room temperature. RESULTS: Forty segments have been used. After defrosting, all the segments kept their normal anatomic shape and structural integrity. Two incisions were made on every tracheal segment and sutured with running or separate stitches with 5-0 polypropilene. There were no complications such as cartilage ruptures, neither tears on the mucosae, the cartilages nor the membranous posterior membrane. CONCLUSIONS: The cryopreserved trachea is a high fidelity, practical, reproducible, portable, low-cost bench model. It allows cardiothoracic fellows to learn how to handle a trachea, as well as to perfect their surgical and suture abilities before applying them on a real patient's trachea.

Cryopreserved tracheal segments: a new tool for bench surgical training in thoracic surgery / Segmentos criopreservados de traqueia: uma nova ferramenta para auxiliar o treinamento na cirurgia torácica

PURPOSE: To present a new low-cost high fidelity bench model of cryopreserved trachea that can be used to learn surgical skills from medical students to cardiothoracic surgery fellows. METHODS: Ten tracheas were harvested from ten non-trachea related research dogs at the moment of euthanasia. Each trachea was trimmed in six or seven rings segments. They were cryopreserved and stored during 60 days. The day programmed for surgical skills practice, they were thawed to room temperature. RESULTS: Forty segments have been used. After defrosting, all the segments kept their normal anatomic shape and structural integrity. Two incisions were made on every tracheal segment and sutured with running or separate stitches with 5-0 polypropilene. There were no complications such as cartilage ruptures, neither tears on the mucosae, the cartilages nor the membranous posterior membrane. CONCLUSIONS: The cryopreserved trachea is a high fidelity, practical, reproducible, portable, low-cost bench model. It allows cardiothoracic fellows to learn how to handle a trachea, as well as to perfect their surgical and suture abilities before applying them on a real patient's trachea.

OBJETIVO: Apresentar novo modelo de traquéia criopreservada de baixo custo e alta fidelidade que pode ser usado tanto por estudantes de medicina como por cirurgiões cardiotorácicos no aprendizado e desenvolvimento de suas habilidades cirúrgicas. MÉTODOS: Foram coletados amostras de dez traquéias de dez cães utilizados para pesquisa após a eutanásia. Cada segmento de traquéia foi dividida em seis ou sete anéis, criopreservadas e armazenadas durante 60 dias. No dia programado para a prática cirúrgica os segmentos foram descongelados a temperatura ambiente. RESULTADOS: Foram utilizados 40 segmentos no estudo. Após o descongelamento todos os segmentos mantiveram sua forma anatômica e sua integridade estrutural. Foram realizadas duas incisões em cada segmento traqueal que foram suturadas em padrão continuo ou com pontos separados utilizando sutura de polipropileno 5-0. Não houve nenhuma complicação como a ruptura da cartilagem, rasgos na mucosa, cartilagem ou na membrana membranosa posterior. CONCLUSÕES: O modelo de traquéia criopreservada é altamente fidedigno, prático, reproduzível, portátil e de baixo custo. Permite que os cirurgiões cardiotorácicos aprendam como manipular a traquéia, assim como aperfeiçoar suas habilidades cirúrgicas antes de sua aplicação em traquéias de pacientes reais.

[Experimental model of canine oleic acid-induced acute lung injury: establishment of a working model]. / Modelo experimental canino de daño pulmonar agudo producido con ácido oleico: estableciendo un modelo de trabajo.

INTRODUCTION: There are several experimental model of acute lung injury induced by oleic acid (OA); however, there are few studies that show how this injury develops. OBJECTIVE: This study seeks to detail the x-ray, hemodynamic, gasometrical, gravimetrical, macroscopic and microscopic alterations developed in an experimental model of canine OA-induced acute lung injury (ALI). MATERIAL AND METHODS: Twelve dogs were divided in 2 study groups: Group I (n=6): Control group without ALI. Group II (n=6); OA-induced ALI. All dogs were submitted to X-ray, hemodynamic and gasometric evaluation before ALI induction, and later every 15 minutes during 150 minutes. At the end of the study, the animals were euthanatized and were evaluated the changes gravimetric, macroscopic and microscopic in injured lungs. RESULTS: All the animals survived through the study. In group II, 100% of the animals developed x-ray (p < 0.003 Wilcoxon), hemodynamic, gasometrical and gravimetric (p < 0.5 ANOVA, Tukey), macroscopically and microscopically (p < 0.001 Wilcoxon) ALI. CONCLUSIONS: The OA-induced ALI is a model in which dogs develop X-ray, hemodynamic, gasometrical, gravimetrical, macroscopically and microscopically injuries of the exudative phase that lung with ALI injury presents.

Lyophilized glutaraldehyde-preserved bovine pericardium for experimental atrial septal defect closure.

A variety of patch materials has been used to close large atrial septal defects (ASD). Autologous pericardium and glutaraldehyde-preserved bovine pericardium are the most used. Lyophilized bovine pericardium has not been tested inside the cardiovascular system. The aim of this work was to study the behaviour and effectiveness of lyophilized glutaraldehyde-preserved bovine pericardium in ASD closure. Sixteen mongrel dogs were operated on. A 3 cm diameter atrial septal defect was created, and closed with: Group I (n=8): Lyophilized glutaraldehyde preserved bovine pericardium (LGPBP). Group II (n=8): Vascular Dacron patch. The animals were evaluated clinically, by echocardiography, macroscopically, and microscopically. Statistical analysis was done with analysis of variance (ANOVA) and Student's t-test. All the animals survived the surgical procedure and study time (6 months). Clinically all the animals displayed normal physical activity, with normal cardiac sounds. Echocardiography showed that both groups had a normal heart without intracardiac shunts, no thrombus formation, and no vegetations. Macroscopically all the animals showed good integration of the lyophilized bioprosthesis and Dacron patch. All group I animals presented a decrease of the area of the ASD in the left atrium (p<0.001 by ANOVA and Student's t-test). Microscopically, group I presented dense and well-organized collagenous tissue, areas of cartilaginous metaplasia and remnants of the lyophilized bioprosthesis (p<0.001 by ANOVA and Student's t-test). Group II showed encapsulated Dacron patch covered with collagenous tissue and cartilaginous metaplasia. In conclusion, the new lyophilized bioprosthesis is well integrated into the atrial septum, without complications and is effective for ASD closure.

[Middle ear packing with collagen-polyvinylpyrrolidone sponge. Experimental study in guinea pigs]. / Empaquetamiento del oído medio con esponja de colágena polivinil pirrolidona. Estudio experimental en cobayos.

INTRODUCTION: Packing material is mandatory in middle ear (ME) surgery in order to avoid inflammation, adhesions and fibrotic healing. Collagen polivynil-pirrolidone (CPVP) is a healing modulator, which reduces inflammation and fibrosis. Hence we can hypothesize that packing of the ME with CPVP sponge will lead a good ME healing. OBJECTIVE: The aim of this study was to evaluate the otoscopic and microscopic changes induced on the healthy mucosa of the ME and Tympanic membrane (TM) after packing with CPVP sponge in guinea pigs. MATERIAL AND METHODS: Twelve guinea pigs were operated on of right myringotomy. The ME was packed with: Group I (n = 6): Absorbable gelatin sponge (AGS) in SS; Group II (n = 6): CPVP soaked in SS. TM and ME integrity was evaluated otoscopically, as well as residual packing material. Euthanasia was performed on the 4th post-operative week. ME mucosa histologic examination was done. RESULTS: Group I in all the cases showed residual packing material (p < 0.007 Student's test p < 0.001 ANOVA). Histologically both groups presented inflammation with polymorphonuclears, in addition group I showed severe lymphocytosis (p < 0.003 Student's, test p < 0.001, ANOVA). CONCLUSION: The CPVP sponge when it is used as material of packing in the OM of guinea pigs produces less chronic inflammatory changes, but more studies with the injured mucosa are required to validate their utility in the otologic surgery.

Wound healing modulators in a tracheoplasty canine model.

Postsurgical tracheal stenosis results from fibrosis formation due to ischemia. There are healing modulators, hyaluronic acid (HA) and collagen polyvinylpyrrolidone (CPVP), which reduce collagen fibers formation. Thus we can hypothesize that the topical application of one of these modulators can diminish postsurgical tracheal scarring and stenosis. The aim of this work was to evaluate the macroscopic, microscopic, and biochemical changes of tracheal healing after the application of HA or CPVP in a canine tracheoplasty model. The study design was prospective experimental investigation in a canine model. Eighteen mongrel dogs underwent three cervical tracheal rings resection and end-to-end anastomosis. They were randomized into three groups according to treatment: group I (control group) (n = 6), topical application of saline solution on tracheal anastomosis; group II (n = 6), topical application of 15 microg HA on tracheal anastomosis; and group III (n = 6), topical application of 2.5 mg CPVP on tracheal anastomosis. They were evaluated clinical, radiological and tracheoscopically during 4 weeks. They were euthanized at the end of the study time. Macroscopic, microscopic, and biochemical changes of tracheal anastomosis healing were analyzed. Collagen formation was quantified by the Woessner method. All the animals survived the surgical procedure and study period. Macroscopic, radiologic, and endoscopic studies showed that animals in group I developed tracheal stenosis, inflammation, and firm fibrous tissue formation, and histological studies also showed severe inflammatory reaction and fibrosis formation. Groups II (HA) and III (CPVP) showed well-organized thin collagen fibers with minimal inflammatory response. Biochemical evaluation revealed a higher collagen concentration in group I animals (analysis of variance [ANOVA] p < .05 and Tukey p < .01). Thus, hyaluronic acid or collagen polyvinylpyrrolidone administered after tracheal anastomosis diminished the degree of stenosis and inflammatory reaction. Both modulators improved tracheal healing.

[Single-layer colonic anastomoses using polyglyconate (Maxon) vs. two-layer anastomoses using chromic catgut and silk. Experimental study]. / Anastomosis colónicas en una sola capa continua con poligliconato (maxon) vs. anastomosis en dos capas con catgut cró6mico y seda. Estudio experimental.

BACKGROUND: The safety of an intestinal anastomosis is usually measured by its complication rate, especially the incidence of anastomotic leakage. A wide variety of methods have been described to reestablish intestinal continuity including single-layer continuous or two-layer interrupted anastomosis. OBJECTIVES: To evaluate if the single-layer continuous anastomosis using polygluconate is safer and reliable than two-layer interrupted anastomosis with chromic catgut and silk. MATERIAL AND METHODS: A prospective, experimental, randomized and comparative analysis was conducted in 20 dogs. They were divided in two groups; group 1 underwent two-layer interrupted anastomosis and group 2 underwent sigle-layer continuous technique. Anastomoses were timed. Both groups were under observation. Anastomotic leakage, and other complications were evaluated. The animals were sacrified and the anastomosis was taken out together with 10 cm of colon on both sides of the anastomosis. Breaking strength, histologic evaluation and hydroxyproline determination were performed. RESULTS: Ten two-layer anastomosis and ten single-layer anastomosis were performed. A median of 25 minutes (range: 20-30 minutes) was required to construct the anastomoses in group 1 versus 20 minutes (range: 12-25 minutes) in group 2. All animals survived and no leakage was observed. Wound infection ocurred in four dogs (20%). Median breaking strength was 230 mm Hg in group 1 and 210 mm Hg in group 2. Hydroxyproline concentration was 8.94 mg/g in group 1 (range: 5.33-16.71) and 9.94 mg/g in group 2 (range: 2.96-21.87). There was no difference among groups about the inflammatory response evaluated by pathology. There was no statistical significance in any variable evaluated. CONCLUIONS: This study demonstrates that a single-layer continuous is similar in terms of safety to the two-layer technique, but because of its facility to perform, the single-layer technique could be superior.

Trasplante experimental de tráquea cervical combinado con la aplicación de factor de crecimiento de fibroblastos / Experimental cervical trachea transplant combined with application of basic fibroblast growth factor

Antecedentes: El trasplante traqueal de longitudes mayores a 6 cm de longitud ha fallado por complicaciones isquémicas del injerto. Experimenta/mente se han utilizado factores de crecimiento y diferentes técnicas quirúrgicas, como la de trasplante traqueal dividido para favorecer la neoformación de vasos sanguíneos. Objetivo: Evaluar la viabilidad, cambios tráquea cervical, macroscópicos y microscópicos del trasplante de tráquea cervical en perros al utilizar la técnica quirúrgica de trasplante traqueal dividido, combinando la aplicación del factor básico de crecimiento para fibroblastos en los sitios de las anastomosis. Material y métodos: Se operaron 24 perros que fueron divididos en 4 grupos de estudio: Grupo I (n = 6): Trasplante de 9 anillos de tráquea cervical con la técnica convencional (TTCC); Grupo II (n = 6): TTCC e instilación tópica de factor básico de crecimiento de fibroblastos (bFGF) en los sitios de anastomosis; Grupo III (n = 6): Trasplante con la técnica de trasplante dividido (TTCD) y Grupo IV (n = 6): TTCD y aplicación de bFGF. Los animales recibieron triple inmunosupresión (azatioprina, metilprednisolona, ciclos-porína). Se planearon evaluaciones clínica, radiológica y traqueoscópica durante 4 semanas. Al final del estudio los injertos trasplantados se evaluaron macroscópica y microscópicamente. Resultados: Ningún animal concluyó su tiempo de estudio por disnea grave durante la primera semana del estudio. Macroscópicamente todos los injertos desarrollaron fístulas y necrosis. Microscópicamente mostraron necrosis, inflamación, vasculitis, hemorragia y destrucción del cartílago. Conclusión: En este estudio encontramos que el trasplante de tráquea cervical mayor a 6 cm, tiene malos resultados con la técnica quirúrgica convencional o dividida e inmunosupresión, así como con y sin la aplicación de bFGF en los sitios de anastomosis.

Background: Tracheal transplantation of lesions larger than 6 cm fails due to ischemic complications. Growth factors and different surgical techniques, including the divided tracheal graft technique, have been used experimentally to stimulate the neoformation of blood vessels. Objective: Assessment of the viability and macroscopic and microscopic changes of the cervical transplanted trachea in dogs, using the divided tracheal graft technique, combined with the application of basic fibroblast growth factor (bFGF) on the anastomotic site. Material and methods: Twenty four mongrel dogs were divided in 4 study groups: Group I (n = 6): Transplantation of 9 cervical tracheal rings with the conventional surgical technique (TCTC). Group II (n = 6): TCTC combined with topical instillation of bFGF at on the anastomotic line. Group III (n = 6): Transplantation of cervical trachea using the divided tracheal graft technique (TCTD), and Group IV (n = 6): TCTD with topical application of bFGF. The animals received triple immunotherapy (azathioprine, methylprednisolone, cyclosporine) and were to have clinical, radiological and endoscopical evaluation during 4 weeks. At the end of the study, macroscopic and microscopic evaluations of the transplanted grafts were done. Results: No animal completed the study time due to severe dyspnea during the first postoperative week. Macroscopically all grafts showed necrosis and fistulae formation. Microscopically we observed necrosis, inflammation, vasculitis, hemorrhage and destruction of cartilage in all the grafts. Conclusion: In this study, tracheal allotransplanta-tion longer than 6 cm with either surgical technique, with immunosuppression, with or without bFGF, is unsuccessful.

Anastomosis colónicas en una sola capa continua con poligliconato (maxon) vs. anastomosis en dos capas con catgut crómico y seda: Estudio experimental / Single layer colonic anastomoses using maxon vs. two layer anastomoses using chromic catgut and silk: structured abstract

Background. The safety of an intestinal anastomosis is usually measured by its complication rate, especially the incidence of anastomotic leakage. A wide variety of methods have been described to reestablish intestinal continuity including single-layer continuous or two-layer interrupted anastomosis. Objectives. To evaluate if the single-layer continuous anastomosis using polygluconate is safer and reliable than two-layer interrupted anastomosis with chromic catgut and silk. Material and methods. A prospective, experimental, randomized and comparative analysis was conducted in 20 dogs. They were divided in two groups; group 1 underwent two-layer interrupted anastomosis and group 2 underwent sigle-layer continuous technique. Anastomoses were timed. Both groups were under observation. Anastomotic leakage, and other complications were evaluated. The animals were sacrified and the anastomosis was taken out together with 10 cm of colon on both sides of the anastomosis. Breaking strength, histologic evaluation and hydroxyproline determination were performed. Results. Ten two-layer anastomosis and ten single-layer anastomosis were performed. A median of 25 minutes (range: 20-30 minutes) was required to construct the anastomoses in group 1 versus 20 minutes (range: 12-25 minutes) in group 2. All animals survived and no leakage was observed. Wound infection ocurred in four dogs (20%). Median breaking strength was 230 mm Hg in group 1 and 210 mm Hg in group 2. Hydroxyproline concentration was 8.94 mg/g in group 1 (range: 5.33-16.71) and 9.94 mg/g in group 2 (range: 2.96-21.87). There was no difference among groups about the inflammatory response evaluated by pathology. There was no statistical significance in any variable evaluated. Conclusions. This study demonstrates that a single-layer continuous is similar in terms of safety to the two-layer technique, but because of its facility to perform, the single-layer technique could be superior.

Antecedentes. Una de las preocupaciones más importantes en cirugía colorrectal es la presencia de dehiscencia o fístula de la anastomosis. Múltiples técnicas han sido descritas para realizar anastomosis, entre las que se incluyen las anastomosis en una sola capa o en dos capas. Objetivos. Evaluar si la anastomosis colonica en una capa con poligliconato es más segura y efectiva que la anastomosis colonica en dos capas con catgut crómico y seda. Material y métodos. Se llevó a cabo un estudio prospectivo, experimental, aleatorio y comparativo en 20 perros. Se dividieron a los animales en dos grupos; grupo 1: anastomosis en dos capas y grupo 2: anastomosis en una sola capa. Se evaluó el tiempo de duración de la anastomosis. Todos los animales se mantuvieron en observación evaluando datos de complicaciones como fístulas colocutáneas o dehiscencia de la anastomosis. En el día diez del postoperatorio se sacrificaron. Se resecó el segmento de la anastomosis abarcando 10 cm proximales y 10 cm distales. Se midió la presión de ruptura, se realizó análisis histopatológico y se determinó la cantidad de hidroxiprolina de la línea de la anastomosis. Resultados. Se incluyeron diez perros en el grupo 1 y diez perros en el grupo 2. La mediana del tiempo de duración de la anastomosis en el grupo 1 fue de 25 minutos (rango: 20-30 minutos) y en el grupo 2 de 20 minutos (rango: 12-25 minutos) (p = NS). No se presentaron datos de fístula, dehiscencia o estenosis de la anastomosis. Cuatro perros presentaron infección en la herida. La presión de ruptura del grupo 1 fue de 230 mm Hg (115-360) y del grupo 2 fue de 210 mm Hg (100-300). La concentración de hidroxiprolina en el grupo 1 fue de 8.94 mg/gramo (rango: 5.33-16.71), y en el grupo 2 fue de 9.94 mg/gramo (rango: 2.96-21.87). No se encontró diferencia significativa en las variables analizadas. Se comparó el grado de reacción inflamatoria en ambos grupos, no hubo diferencia estadística. Conclusiones. Los dos procedimientos son seguros y confiables de realizar, aunque por su mayor facilidad, estos datos apoyan la utilización del método de una sola capa.