Polypropylene mesh inhibits post-laminectomy compressive scar formation in rabbits: Histopathological and computational morphometric evaluation.

We evaluated the effect of polypropylene mesh placement on post-laminectomy compressive scar formation in rabbits. Twenty-two white male New Zealand rabbits were distributed into two groups (n = 11). In the control group, the animals underwent lumbosacral laminectomy, whereas in the mesh group, the rabbits were submitted to lumbosacral laminectomy followed by the attachment of a polypropylene mesh to the vertebrae by the application of N-butyl cyanoacrylate. After eight weeks, the rabbits were euthanized, and the laminectomy area was collected for macro- and microscopic analyses. Macroscopically, we evaluated the (1) vertebral canal height; (2) laminectomy width and (3) length; and (4) fibrosis width, (5) height, and (6) length. Microscopically, we evaluated (7) fibroblasts; (8) the thickness of the dura-mater; and (9) the distance between the dura-mater and the laminectomy area. Macroscopically, there were no differences between the groups regarding vertebral canal height; width and length of the laminectomy; and fibrosis width. However, the height, and length of fibrosis were smaller in the mesh group. Microscopically, there were no differences in dura mater thickness and the distance between the dura mater and laminectomy area, but fewer fibroblasts were observed in the mesh group. This indicated that the polypropylene mesh improved tissue repair, with greater tissue organization. The results demonstrate that the use of a polypropylene mesh in the treatment of post-laminectomy wounds in rabbits reduces the severity of compressive fibrous scar formation. Polypropylene mesh is presented as a good alternative to reduce complications associated with laminectomy surgeries.

EFFECTS OF DIFFERENT PERIODS OF GASTRIC ISCHAEMIA IN THE VIABILITY OF THE TISSUE OF BODY, FUNDUS AND ANTRUM REGION OF RABBIT STOMACH / EFEITOS DE DIFERENTES TEMPOS DE ISQUEMIA GÁSTRICA SOBRE A VIABILIDADE DOS TECIDOS DO CORPO, FUNDO E ANTRO DO ESTÔMAGO DE COELHOS

BACKGROUND: Despite the rich vascular arcade of the stomach, gastric ischemia represents an important medical challenge and can be the consequence of obstructive or non-obstructive vascular processes of pathological or iatrogenic origin.AIM: To assess the effects of acute gastric ischaemia on the different regions of the stomach.METHOD: Fifteen New Zeland rabbits were divided into three groups: group 1, animals were observed during 3 h; group 2, during 6 h; group 3, during 12 h. Rabbit stomachs were subjected to devascularization of the greater and lesser curvatures. After predetermined time, the stomachs were removed for macro and microscopic studies.RESULTS: Haemorrhagic necrosis was more marked in the gastric fundus and body. In contrast, the antropylorus remained preserved in 80% of the animals. Necrosis of the gastric body and fundus mucosa were observed in all animals after 6 h and 12 h of ischaemia.CONCLUSION: Acute gastric ischaemia in rabbits produces haemorrhagic necrosis of the gastric fundus and body even in a short period of time. Beside this, the antropyloric region was significantly more resistant to ischaemia.

RACIONAL: Isquemia gástrica representa importante desafio médico e geralmente é decorrente de processos vasculares obstrutivos ou não-obstrutivos. Apesar da rica arcada vascular do estômago, lesões de isquemia gástrica têm sido observadas. Quando a isquemia progride, pode culminar em necrose do órgão.OBJETIVO: Avaliar os efeitos dos diferentes tempos de isquemia gástrica sobre os tecidos da parede do estômago de coelhos mediante desvascularização total de ambas as curvaturas gástricas.MÉTODO: Foram utilizados 15 coelhos machos da raça Nova Zelândia. Os animais foram distribuídos nos seguintes grupos: grupo 1, observados por 3 h; grupo 2, por 6 h; grupo 3, por 12 h. A técnica cirúrgica foi a mesma em todos os animais e consistiu na ligadura e secção de todas as veias e artérias da parede gástrica. Após o período pré-determinado de observação, o estômago foi removido por completo para estudo macro e microscópico.RESULTADOS: As alterações macroscópicas e histológicas tornaram-se mais intensas com o aumento do tempo de isquemia e foram mais evidentes nas regiões do fundo e do corpo. Por outro lado, o antro manteve-se preservado na maioria dos animais operados. Necrose de mucosa do corpo e do fundo foi observada em todos os animais estudados, e foi acompanhada por hemorragia em 60% dos coelhos dos grupos 2 e 3.CONCLUSÃO: O modelo experimental de isquemia gástrica foi eficaz para produzir necrose hemorrágica de fundo e corpo do estômago de coelhos mesmo em curto tempo. Por outro lado, a região do antro pilórico desses animais mostrou-se significativamente mais resistente à isquemia do que as demais regiões.

Effects of different periods of gastric ischaemia in the viability of the tissue of body, fundus and antrum region of rabbit stomach.

BACKGROUND: Despite the rich vascular arcade of the stomach, gastric ischemia represents an important medical challenge and can be the consequence of obstructive or non-obstructive vascular processes of pathological or iatrogenic origin. AIM: To assess the effects of acute gastric ischaemia on the different regions of the stomach. METHOD: Fifteen New Zeland rabbits were divided into three groups: group 1, animals were observed during 3 h; group 2, during 6 h; group 3, during 12 h. Rabbit stomachs were subjected to devascularization of the greater and lesser curvatures. After predetermined time, the stomachs were removed for macro and microscopic studies. RESULTS: Haemorrhagic necrosis was more marked in the gastric fundus and body. In contrast, the antropylorus remained preserved in 80% of the animals. Necrosis of the gastric body and fundus mucosa were observed in all animals after 6 h and 12 h of ischaemia. CONCLUSION: Acute gastric ischaemia in rabbits produces haemorrhagic necrosis of the gastric fundus and body even in a short period of time. Beside this, the antropyloric region was significantly more resistant to ischaemia.

Greater resistance of the rabbit antropyloric region to experimental acute gastric ischemia / Maior resistência da região antropilórica de coelhos à isquemia gástrica aguda experimental

INTRODUCTION: Gastric ischemia represents an important medical challenge in pathology and surgical practice. OBJECTIVE: The purpose of this study was to assess the effects of acute gastric ischemia on different regions of the stomach. METHOD: Rabbit stomachs were subjected to devascularization of the greater and lesser curvatures for 3, 6 and 12 hours. After these periods, the stomachs were removed for macro and microscopic analysis. RESULTS: Hemorrhagic necrosis was more marked in the gastric fundus and body. In contrast, the antropylorus remained preserved in 100% of the rabbits after 3 hours of ischemia (group I), and in 80% of the rabbits after 6 and 12 hours of ischemia (groups II and III). Necrosis of the gastric body and fundus mucosa were observed in all animals after 6 and 12 hours of ischemia. CONCLUSION: We concluded that this experimental model of acute gastric ischemia was effective in producing hemorrhagic necrosis of the gastric fundus and body in rabbits even within a short period of time. Furthermore, the antropyloric region was preserved in most animals.

INTRODUÇÃO: Isquemia gástrica representa um importante desafio médico nas áreas de Patologia e Cirurgia. O objetivo do presente trabalho foi avaliar os efeitos da isquemia gástrica aguda nas diferentes regiões do estômago. MÉTODO: Estômagos de coelhos foram submetidos à completa desvascularização das curvaturas maior e menor durante 3, 6 e 12 horas. Após esses períodos de tempo, os órgãos foram removidos para análise macro e microscópica. RESULTADOS: Necrose hemorrágica foi mais evidente nas regiões de corpo e fundo. Por outro lado, a região antropilórica manteve-se preservada em 100% dos coelhos após 3 horas de isquemia (grupo I), e em 80% dos coelhos após 6 e 12 horas de isquemia (grupos II e III). Necrose da camada mucosa do corpo e do fundo gástricos foi observada em todos os animais após 6 e 12 horas de isquemia. CONCLUSÃO: Conclui-se que esse modelo de isquemia gástrica aguda foi eficaz para produzir necrose hemorrágica do corpo e fundo de coelhos mesmo por um curto período de tempo. Além disso, a região antropilórica manteve-se preservada na maioria dos animais.