GastroplastyObesity, MorbidJejunoileal BypassGastric BypassAnastomosis, Roux-en-YPirinitramideSurgical StaplersStomachHernia, HiatalWeight LossEsophageal StenosisFundoplicationEsophagusBariatric SurgeryLaparoscopyPostoperative ComplicationsGastroesophageal RefluxPostoperative PeriodReoperationObesityMethodsFollow-Up Studies