RESUMEN
AIM: To evaluate the clinical effects of personalized customized gluteus maximus myocutaneous flaps (GMMF) for reconstruction of extensive sacrococcygeal soft tissue defects in complex tumor patients. METHODS: A retrospective chart review was conducted on 8 patients who underwent personalized customized GMMF reconstruction for large sacrococcygeal defect from December 2021 to August 2023. The personalized customized GMMF were designed based on the variations of tissue defect in location, shape and volume of different dead spaces. The principle of the personalized GMMF is to ensure that the rotation point of the flap can reach the farthest end of the defect. Patient demographics, operative characteristics, and perioperative risk factors were analyzed. Clinical outcomes were assessed, focusing on complications such as flap necrosis, wound dehiscence, infection, seroma, and hematoma. RESULTS: Six patients with rectal cancer and two with sacral tumors underwent personalized customized GMMF reconstruction for extensive sacrococcygeal defects. The average volume of the wound cavity was 104 mL, with a mean vertical depth was 10.8 cm. Six patients had low serum albumin (<35 g/L). After a mean follow-up of 15.5 months, no major complications occurred, except for one seroma that resolved within 2 weeks. CONCLUSION: The personalized customized GMMF described in this study is an effective method for reconstructing large sacrococcygeal wounds with significant depth in complex tumor patients. It allows for greater rotation of the muscle flap into the sacrococcygeal wound defect and provides adequate blood supply by utilizing the bulk of muscle tissue to obliterate dead space.
RESUMEN
A hybrid girder bridge adopts a steel segment at the mid-span of the main span of a continuous concrete girder bridge. The critical point of the hybrid solution is the transition zone, connecting the steel and concrete segments of the beam. Although many girder tests revealing the structural behavior of hybrid girders have been conducted by previous studies, few specimens took the full section of a steel-concrete joint due to the large size of prototype hybrid bridges. In this study, a static load test on a composite segment to bridge the joint between the concrete and steel parts of a hybrid bridge with full section was conducted. A finite element model replicating the tested specimen results was established through Abaqus, while parametric studies were also conducted. The test and numerical results revealed that the concrete filling in the composite solution prevented the steel flange from extensive buckling, which significantly improved the load-carrying capacity of the steel-concrete joint. Meanwhile, strengthening the interaction between the steel and concrete helps to prevent the interlayer slip and simultaneously contributes to a higher flexural stiffness. These results are an important basis for establishing a rational design scheme for the steel-concrete joint of hybrid girder bridges.