Preserving Duodenal Passage for Bone Mineralization: Billroth I versus Billroth II Reconstruction After Partial Gastrectomy in Growing Minipigs

IntroductionRecent data in morbid obesity surgery have shown that the Roux-en-Y gastric bypass results in a decrease in bone mass. Therefore, we investigated the impact of duodenal exclusion on bone mineralization in respect to newer duodenal preserving operations in morbid obesity surgery.MethodsTwelve female minipigs underwent Billroth I (n = 6) or Billroth II (n = 6) reconstruction. Serum parameters were investigated and bone mineral density of the fourth lumbar vertebra was evaluated by quantitative CT scan at monthly intervals over a 1-y period. Calcium absorption was measured as 47calcium-carbonate at 3-mo intervals.ResultsAt the end of the study, the cancellous volumetric bone mineral density (cancvBMD) and the cortical volumetric bone mineral density (cortvBMD) were significantly more decreased in Billroth II (BII) than in Billroth I (BI) reconstructed minipigs (371.86 ± 1.61 versus 386.96 ± 5.01 mg/cm3; 402.22 ± 1.64 versus 410.7 ± 2.08 mg/cm3; both P < 0.05). Similar distribution was measured for cancellous and cortical bone mineral content (670.0 ± 7.5 versus 712.8 ± 11.3 mg; 682.2 ± 40.5 versus 717.8 ± 43.4 mg; both P < 0.05). Medullary and cortical areas were significantly decreased in BII pigs compared with BI pigs. 47Ca absorption was significantly decreased in BII 3 and 6 mo following the operation, then reached values similar to those in BI animals.ConclusionExclusion of the duodenum from the passage resulted in impaired mineralization of the axial skeleton due to decreased calcium absorption and impaired vertebral bone volume.