RESUMO
Purpose@#This study aimed to assess the outcomes of revisional procedures, namely Roux-en-Y gastric bypass (RYGB) and one anastomosis gastric bypass (OAGB) following unsuccessful laparoscopic sleeve gastrectomy. @*Materials and Methods@#This systematic review and meta-analysis included 817 patients (404 in OAGB group, 413 in RYGB group) from seven retrospective comparative studies. Data on sample size, demographics, perioperative complications, operative time, pre- and post-revisional body mass index, total weight loss, and global weight loss over follow-up were extracted. @*Results@#The mean operative time was 98.2–201 minutes for RYGB versus 78.7–168 minutes for OAGB. Despite classical RYGB gastric bypass taking longer, mini gastric bypass resulted in greater weight loss than RYGB, with a mean difference of −5.84 (95% confidence interval [CI], −6.74 to −4.94; P<0.00001; I 2 =0%), greater total weight loss, and a higher diabetes remission rate (odds ratio [OR], 0.32; 95% CI, 0.14 to 0.71). However, OAGB was associated with a significantly higher incidence of postoperative gastroesophageal reflux than RYGB (52 vs. 31: OR, 0.40; 95% CI, 0.24 to 0.67; P=0.0005; I 2 =0%). @*Conclusion@#OAGB was performed more quickly and boasted greater total weight loss and higher diabetes remission rates compared to RYGB after failed sleeve gastrectomy. However, OAGB also demonstrated a higher incidence of postoperative gastroesophageal reflux disease. Thus, careful patient selection is essential when considering OAGB.
RESUMO
An elastic cloak is a coating material that can be applied to an arbitrary inclusion to make it indistinguishable from the background medium. Cloaking against elastic disturbances, in particular, has been demonstrated using several designs and gauges. None, however, tolerate the coexistence of normal and shear stresses due to a shortage of physical realization of transformation-invariant elastic materials. Here, we overcome this limitation to design and fabricate a new class of polar materials with a distribution of body torque that exhibits asymmetric stresses. A static cloak for full two-dimensional elasticity is thus constructed based on the transformation method. The proposed cloak is made of a functionally graded multilayered lattice embedded in an isotropic continuum background. While one layer is tailored to produce a target elastic behavior, the other layers impose a set of kinematic constraints equivalent to a distribution of body torque that breaks the stress symmetry. Experimental testing under static compressive and shear loads demonstrates encouraging cloaking performance in good agreement with our theoretical prediction. The work sets a precedent in the field of transformation elasticity and should find applications in mechanical stress shielding and stealth technologies.