Tissue sealants for the prevention of lymphoceles after radical inguinal lymph node dissection in patients with melanoma: A systematic review and individual patient data meta-analysis.

BACKGROUND AND OBJECTIVES: Postoperative lymphoceles and further wound complications occur frequently after radical inguinal lymph node dissection (ILND). In various studies, tissue sealants have shown to reduce the incidence of postoperative morbidity. METHODS: A systematic review and meta-analysis of randomized controlled trials (RCTs) investigating the effectiveness of tissue sealants in reducing the incidence of postoperative lymphoceles following ILND in patients with melanoma was conducted. Individual patient data was requested to pool the data for meta-analysis appropriately. RESULTS: Thousand seven hundred twenty-nine manuscripts were screened for eligibility. Six RCTs published between 1986 and 2012 were identified including 194 patients for ILND. Only four RCTs were included in the meta-analysis. No study properly defined the term "lymphocele." Tissue sealants failed to influence the duration of drain placement (mean difference [MD] = -3.05 days; z = 1.18; P = 0.24), total drainage volume (MD = 598.39 mL; z = 1.49; P = 0.14), the incidence of postoperative seroma, wound infection and skin necrosis. CONCLUSIONS: No improvement was identified with the use of tissue sealants, however, a valid comparison of the results of included trials was difficult owing to the lack of a definition of the term "lymphocele." Other surgical techniques and trials using validated endpoint definitions are required to reevaluate these findings.

Mechanical properties of mesh materials used for hernia repair and soft tissue augmentation.

BACKGROUND: Hernia repair is the most common surgical procedure in the world. Augmentation with synthetic meshes has gained importance in recent decades. Most of the published work about hernia meshes focuses on the surgical technique, outcome in terms of mortality and morbidity and the recurrence rate. Appropriate biomechanical and engineering terminology is frequently absent. Meshes are under continuous development but there is little knowledge in the public domain about their mechanical properties. In the presented experimental study we investigated the mechanical properties of several widely available meshes according to German Industrial Standards (DIN ISO). METHODOLOGY/PRINCIPAL FINDINGS: Six different meshes were assessed considering longitudinal and transverse direction in a uni-axial tensile test. Based on the force/displacement curve, the maximum force, breaking strain, and stiffness were computed. According to the maximum force the values were assigned to the groups weak and strong to determine a base for comparison. We discovered differences in the maximum force (11.1±6.4 to 100.9±9.4 N/cm), stiffness (0.3±0.1 to 4.6±0.5 N/mm), and breaking strain (150±6% to 340±20%) considering the direction of tension. CONCLUSIONS/SIGNIFICANCE: The measured stiffness and breaking strength vary widely among available mesh materials for hernia repair, and most of the materials show significant anisotropy in their mechanical behavior. Considering the forces present in the abdominal wall, our results suggest that some meshes should be implanted in an appropriate orientation, and that information regarding the directionality of their mechanical properties should be provided by the manufacturers.

Acellular dermal matrix seeded with autologous fibroblasts improves wound breaking strength in a rodent soft tissue damage model in neoadjuvant settings.

Soft tissue defects following resectional surgery or trauma often result in deadspaces and require free or pedicled flaps. A programmed formation of filling tissue with enhanced biomechanical properties could be helpful. This study examined the effects on wound healing of acellular dermal matrix (ADM) seeded with autologous fibroblasts in a standardized rodent model. As pre- or postoperative radiotherapy is standard in many treatments of malignancies, we also investigated the effects of additional radiotherapy. Fischer rats were randomised and received a standardized unilateral soft tissue defect at the buttock. The defect was filled with ADM+fibroblasts or ADM alone. Controls received no filling. Either no radiation, adjuvant (postoperative) or neoadjuvant (preoperative) radiation was applied to the defect site. Six weeks later the defect volume was measured by MR-tomography. Wound breaking strength was examined by tensiometry according to German Industrial Standards. Filling of the defect side was significantly larger in ADM and ADM+fibroblast treated groups compared to the control group in all settings. Wound breaking strength in the unimodal setting was significantly improved in the ADM+fibroblasts group compared to the ADM group. In the neoadjuvant setting there was no significant difference between control and ADM group. However, the ADM+fibroblasts groups showed a significantly increased wound breaking strength compared to the control and the ADM-alone group. Seeded or unseeded ADM is able to fill deadspace in this rodent model in all settings. Implanting non-irradiated, vital, proliferating autologous fibroblasts on ADM results in significantly increased wound breaking strength.