[Clinical evidence for metabolic surgery]. / Klinische Evidenz der metabolischen Chirurgie.

The metabolic effect of bariatric surgery is well-established and is considered to be self-evident in morbidly obese patients with a body mass index (BMI) > 40 kg/m(2). Metabolic surgery performed on patients with obesity grades II (BMI 35-40 kg/m(2)) and I (BMI 30-35 kg/m(2)) according to the World Health Organization (WHO) has increased in recent years; however, the indications for metabolic surgery in obesity grades I and II are currently under debate due to insufficient evidence. In the last 5 years several highly qualified randomized clinical trials have been published which evaluated the effect of metabolic surgery in patients with obesity grades I and II in comparison to conservative therapy. Based on these data the efficacy of metabolic surgery in short-term follow-up (12-36 months) is unquestionable when compared to conservative therapy according to the current guidelines. Besides improved glycemic control and remission of diabetes, metabolic surgery has the potential to have a positive influence on diabetic complications, such as diabetic retinopathy, nephropathy and polyneuropathy, as well as on comorbidities, such as arterial hypertension and dyslipidemia. Future clinical trials should address the long-term (> 36 months) effects of metabolic surgery, patient selection criteria and choice of procedure.

Polypropylene, polyester or polytetrafluoroethylene-is there an ideal material for mesh augmentation at the esophageal hiatus? Results from an experimental study in a porcine model.

PURPOSE: Knowledge about the influence of underlying biomaterial on behavior of surgical meshes at the esophageal hiatus is rare, but essential for safe and effective hiatal hernia surgery. This study aimed to characterize the influence of polymer material on mesh behavior at the hiatus. METHODS: 24 pigs in three groups of eight underwent implantation of either polypropylene (PP), polyester (PET) or polytetrafluoroethylene (PTFE) mesh placed circularly at the esophageal hiatus. After 8 weeks, necropsy and measurements were performed evaluating mesh deformation, adhesion formation, fixation of the esophagogastric junction and mesh position. Foreign body reaction was assessed by mononuclear cell count and immunostaining of Ki-67. Tissue integration was evaluated by immunostaining of type I and type III collagen fibers. RESULTS: Mesh shrinkage was the highest for PTFE, lower for PP and the lowest for PET (34.9 vs. 19.8 vs. 12.1 %; p = 0.002). Mesh aperture for the esophagus showed an enlargement within all groups, which was highest for PTFE compared to PP and PET (100.8 vs. 47.0 vs. 35.9 %; p = 0.001). The adhesion score was highest for PP, lower for PTFE and the lowest for PET (11.0 vs. 9.5 vs. 5.0; p = 0.001) and correlated positively with the score of esophagogastric fixation (r s = 0.784, p < 0.001). No mesh migration, erosion or stenosis of the esophagus occurred. Evaluation of foreign body reaction and tissue integration showed no significant differences. CONCLUSIONS: In this experimental setting, PP-meshes showed the most appropriate characteristics for augmentation at the hiatus. Due to solid fixation of the esophagogastric junction and low shrinkage tendency, PP-meshes may be effective in preventing hiatal hernia recurrence. The use of PTFE-mesh at the hiatus may be disadvantageous due to high shrinkage rates and correlating enlargement of the aperture for the esophagus.