Polyetheretherketone (PEEK) as a new type of thermoplastic engineering plastic, has good biological activity, elastic modulus close to human cortical bone and radiation permeability, and has been widely used in medical field. This study aims to explore the safety and clinical efficacy of using 3D printing personalized PEEK materials to repaire scapular bone defects after bone tumor resection. A total of 6 patients who underwent the implantation of 3D printed PEEK scapular prosthesis from January 2020 to December 2021 in Yunnan Cancer Hospital were retrospectively analyzed. There were 3 males and 3 females, with age ranged from 14 to 52 years. There were 1 case of synovial sarcoma, 1 of Ewing's sarcoma, and 4 of chondrosarcoma. PEEK prosthesis was designed and fabricated based on CT data before surgery. Tumor resection and prosthesis replacement were performed under the premise of ensuring safe surgical boundaries, including 2 cases of total scapular prosthesis replacement and 4 cases of partial scapular prosthesis replacement. The operation time was 90-170 min, and the intraoperative blood loss was 100-400 ml. All 6 patients received satisfactory follow-up, with a tumor progression free survival time of 16-28 months. No tumor recurrence or metastasis was observed, and all patients survived tumor free. At last follow-up, the Constant-Murley shoulder joint score was a minimum of 62 points and a maximum of 68 points. The Japanese Orthopaedic Association's shoulder joint score was 63 points minimum and 78 points maximum. Computer-aided design 3D printing PEEK material prosthesis has certain advantages in the treatment of scapular tumor limb salvage. It has light weight, well adapted, relatively simple installation, good histocompatibility, and can obtain a better appearance and function of the shoulder joint after operation. It can become one of the options for limb salvage treatment of scapular tumor.

Objective To investigate the effect of fluid shear(FS)on apoptosis of glomerular epithelial cells(GECs)and the role of Piezo 1 protein in it.Methods GECs(glomerular epithelial cells)of SD rat were cul-tured.Fluid shear stimulation was simulated by a Flexcell-T5000 tensiometer.Apoptosis level was detected by flow cytometry.The expression of Piezo 1 proteins in GECs was detected by immunofluorescence staining.The activating of Piezo 1 channels by fluid shear was observed using Ca2+indicator(Cal-590 AM).The effect of Piezo 1 on apop-tosis in GECs was analyzed after modulating the function or expression of Piezo 1 protein using the chemical activa-tor Yoda1,the inhibitor GsMtx 4 was regulated by lentivirus Lv-shPiezo 1.Results Compared with the blank controlgroup,apoptosis increased in the fluid shear group(P＜0.05).The rate of apoptosis increased with the enhancing of fluid shear strength;Piezo 1 was commonly expressed in GECs.Fluid shear activated Piezo 1 chan-nel and enhanced expression of Piezo 1.The agonist Yoda1 promoted the apoptosis of GECs GsMtx 4 inhibited the apoptosis induced by fluid shear.Lv-shPiezo 1 knocked down the expression of Piezo 1 in GECs and the apoptosis rate of GECs in the knockdown group was reduced as compared to that in the control group and Lv-Ctrl group(P＜0.05).Conclusions Fluid shear may promote apoptosis of GECs by activation of Piezo 1 and by enhancing expression of Piezo 1.