RESUMEN
Background: The open abdomen with mesh implantation, followed by early reoperation with fascial closure, is a modern surgical approach in difficult clinical situations such as severe abdominal sepsis. As early fascial closure is not possible in many cases, mesh-mediated fascial traction is helpful for conditioning of a minimized ventral hernia after open abdomen. The aim of this study was to evaluate the clinical utilization of an innovative elastic thermoplastic polyurethane mesh (TPU) as an abdominal wall inlay in a minipig model. Methods: Ten minipigs were divided in two groups, either receiving an elastic TPU mesh or a nonelastic polyvinylidene fluoride (PVDF) mesh in inlay position of the abdominal wall. After 8 weeks, mesh expansion and abdominal wall defect size were measured. Finally, pigs were euthanized and abdominal walls were explanted for histological and immunohistochemical assessment. Results: Eight weeks after abdominal wall replacement, transversal diameter of the fascial defect in the TPU group was significantly smaller than in the PVDF group (4.5 cm vs. 7.4 cm; p = 0.047). Immunhistochemical analysis showed increased Ki67 positive cells (p = 0.003) and a higher number of apoptotic cells (p = 0.047) after abdominal wall replacement with a TPU mesh. Collagen type I/III ratio was increased in the PVDF group (p = 0.011). Conclusion: Implantation of an elastic TPU mesh as abdominal wall inlay is a promising approach to reduce the size of the ventral hernia after open abdomen by mesh-mediated traction. However, this effect was associated with a slightly increased foreign body reaction in comparison to the nonelastic PVDF.
Asunto(s)
Técnicas de Cierre de Herida Abdominal/instrumentación , Hernia Ventral/prevención & control , Complicaciones Posoperatorias/prevención & control , Mallas Quirúrgicas , Herida Quirúrgica/complicaciones , Pared Abdominal/cirugía , Animales , Modelos Animales de Enfermedad , Elasticidad , Femenino , Hernia Ventral/etiología , Humanos , Poliuretanos , Polivinilos , Complicaciones Posoperatorias/etiología , Porcinos , Porcinos EnanosRESUMEN
BACKGROUND: The frequency of laparoscopic approaches increased in hernia surgery over the past years. After mesh placement in IPOM position, the real extent of the meshes configurational changes after termination of pneumoperitoneum is still largely unknown. To prevent a later mesh folding it might be useful to place the mesh while it is kept under tension. Conventionally used meshes may lose their Effective Porosity under these conditions due to poor elastic properties. The aim of this study was to evaluate a newly developed elastic thermoplastic polyurethane (TPU) containing mesh that retains its Effective Porosity under mechanical strain in IPOM position in a porcine model. It was visualized under pneumoperitoneum using MRI in comparison to polyvinylidenefluoride (PVDF) meshes with similar structure. METHODS: In each of ten minipigs, a mesh (TPU containing or native PVDF, 10 × 20 cm) was randomly placed in IPOM position at the center of the abdominal wall. After 8 weeks, six pigs underwent MRI evaluation with and without pneumoperitoneum to assess the visibility and elasticity of the mesh. Finally, pigs were euthanized and abdominal walls were explanted for histological and immunohistochemical assessment. The degree of adhesion formation was documented. RESULTS: Laparoscopic implantation of elastic TPU meshes in IPOM position was feasible and safe in a minipig model. Mesh position could be precisely visualized and assessed with and without pneumoperitoneum using MRI after 8 weeks. Elastic TPU meshes showed a significantly higher surface increase under pneumoperitoneum in comparison to PVDF. Immunohistochemically, the amount of CD45-positive cells was significantly lower and the Collagen I/III ratio was significantly higher in TPU meshes after 8 weeks. There were no differences regarding adhesion formation between study groups. CONCLUSIONS: The TPU mesh preserves its elastic properties in IPOM position in a porcine model after 8 weeks. Immunohistochemistry indicates superior biocompatibility regarding CD45-positive cells and Collagen I/III ratio in comparison to PVDF meshes with a similar structure.
Asunto(s)
Pared Abdominal/cirugía , Hernia Abdominal/cirugía , Laparoscopía/métodos , Poliuretanos/química , Mallas Quirúrgicas , Animales , Elasticidad , Femenino , Imagen por Resonancia Magnética , Ensayo de Materiales/métodos , Modelos Animales , Neumoperitoneo Artificial , Porosidad , Prótesis e Implantes , Estrés Mecánico , Porcinos , Porcinos EnanosRESUMEN
BACKGROUND: Postsurgical adhesions severely affect the patients' quality of life causing various complications like bowel obstruction or chronic pain. Especially the implantation of alloplastic prostheses in IPOM position for hernia repair carries a high risk of adhesion formation due to the close contact between mesh and viscera. The extent of adhesions mainly depends on the type and textile characteristics of the implanted mesh. The aim of this study was to examine the degree of adhesion formation of a newly developed, elastic thermoplastic polyurethane (TPU) mesh in comparison to polypropylene (PP) meshes in IPOM position in a rabbit model. METHODS: Sixteen female chinchilla rabbits were laparoscopically operated. Two different meshes were placed to the left and the right lower abdominal wall in IPOM position in each rabbit. After 7 or 21 days, midline laparotomy was performed, the degree of adhesion formation was examined by the Diamond score and mesh elongation was measured under a force of 3N. Finally, the abdominal walls were explanted for immunohistochemical and histopathological investigations. RESULTS: TPU meshes showed significantly lower Diamond scores than PP meshes. After explantation, mesh elongation of the TPU mesh was significantly larger than expansion of PP under a force of 3N. Thus, the TPU mesh preserved its elastic properties after 7 and 21 days. The amount of CD68 positive, Ki67 positive and apoptotic cells within the granuloma around the fibers did not show significant differences between the study groups. CONCLUSIONS: The newly developed TPU mesh seems to reduce peritoneal adhesion formation in IPOM position in a rabbit model compared to PP meshes after 7 and 21 days. Immunohistochemistry did not reveal differences in biocompatibility of the two meshes used.