Naoto Shiba

Profiles Associated with Sarcopenia in Hepatoma Patients Underwent Transcatheter Arterial Chemoembolization: A Data-Mining Analysis

Sarcopenia is a prognostic factor in patients with hepatocellular carcinoma (HCC). Transcatheter arterial chemoembolization (TACE) may aggravate sarcopenia because of post‐embolization syndrome. The aims of this study are to investigate changes in skeletal muscle mass after TACE and its risk profiles in patients with HCC.

Computer Simulation of Hip Osteotomies for Dysplastic Coxarthroses: Use of a Rigid Body Spring Model

We have used the rigid body spring model (RBSM) or discrete element analysis to investigate the biomechanical effect of hip osteotomies. A two-dimensional (2-D) two-element model was generated by anteroposterior (A-P) radiography. The pelvic and femoral elements were assumed to be rigid and interface springs were placed 1 mm apart along the articular contact area to simulate articular cartilage. Four subjects, who had a normal hip joint, early, advanced, and late stage of coxarthroses, respectively, were analyzed. The coxarthrotic subjects were analyzed preoperatively and at final follow-up. The resultant and modified resultant force of the femoral head, dislocation force, mean and maximum compressive stress on the joint, and X—Y and rotational deviations of the pelvic element were calculated. In the normal hip joint, the stress pattern on the joint surface was similar to the “sourcil” (“eyebrow”), as described by Pauwels [1]. In preoperative coxarthrosis, extreme stress was seen on the joint, especially where the joint space was narrowed. A dislocation force not observed in a normal hip joint was apparent, with the X—Y and rotational deviations being larger than in the normal hip joint. This tendency increased with progressing stages of coxarthrosis. In the final follow-up examination, all the simulated results were in contrast to those obtained preoperatively. A 3-D reconstruction computerized tomographic (CT) scan was used to visualize the hip joint and its operation, but this procedure is not clinically practical for every patient. Surgeons usually use only plane radiograms when planning hip operations, such as osteotomy or total hip arthroplasty. The RBSM is therefore clinically useful because of its simplicity, and 2-D RBSM can easily be utilized by using A-P radiograms for each patient. With this method the patient’s past radiographic data can also be utilized. A comparative study of clinical symptoms and simulated results using 2-D RBSM suggested that the simulated results were well correlated to the clinical symptoms. RBSM is clinically useful not only for evaluating each patient biomechanically but also for planning hip osteotomy.