Objective To evaluate the surgical procedure of reinforced acetabular cage with caudal flange in reconstruction of pelvic defect after acetabular tumor resection. Methods Between June 2003 and December 2009, 25 patients with Harrington class III pelvic defect underwent reconstruction with a reinforced acetabular cage with caudal flange and total hip arthroplasty (THA). There were 13 males and 12 females with an average age of 51.2 years (range，13-73 years). The main cl inical manifestations included hip pain and buttock pain, with a median disease duration of 6 months (range, 1-96 months). Pathological findings showed 18 cases of metastasis, 3 cases of multiple myeloma, 1 case of non-Hodgkin’s lymphoma, 1 case of grade I chondrosarcoma, 1 case of giant cell tumor, and 1 case of chondroblastoma. For the patient with chondroblastoma, THA with LINK RIBBED system was used. An artificial total hip system made in China was used in 6 patients and LINK SP II system was used in the other 18 patients. Results No patients died perioperatively. Deep infection and hip dislocations occurred in 1 and 2 patients, respectively. At last follow-up, 8 of 18 patients with metastasis died of cancer and the average survival time was 11 months. The other 10 who were al ive were followed up 15 months on average. One patient with multiple myeloma died of pulmonary infection at 21 months after operation and the other 2 with multiple myeloma and 1 with lymphoma were al ive with an average follow-up of 17 months. The patient with grade I chondrosarcoma and patient with chondroblastoma were followed up 58 and 12 months, respectively, without recurrence. Recurrence occurred in the patient with giant cell tumor at 19 months afteroperation. Loosening of implant occurred in 3 patients because of local tumor recurrence. For the 23 patients at 6 months after operation, the mean Musculoskeletal Tumor Society (MSTS) 93 score was 81% (range, 57%-93%). Conclusion Reinforced acetabular cage with caudal flange could be used together with THA for reconstruction of Harrington class III pelvic defects after acetabular tumor resection, and low incidence of postoperative compl ication and good functional outcome could be expected.
ObjectiveTo summarize the research progress of surgical treatment for primary sacrum tumor. MethodThe domestic and foreign related literature about surgical treatment of primary sacrum tumor, and many aspects of its surgical procedures, intraoperative hemostasis, pelvic reconstruction, protection of sacral nerve, complications, and prognosis was summarized and analyzed. ResultsThe operation is the major therapy for primary sacrum tumor. However, surgical procedures, protection of sacral nerve, and the way of intraoperative hemostasis remain controversial. Meanwhile, the complexity of pelvic reconstruction, the diversity of complications, and prognosis related with many factors bring difficulties and challenges to the surgical treatment. ConclusionsIt is urgent need to develop an effective unified standard to conduct diagnosis and treatment of primary sacrum tumor.
ObjectiveTo analyze the biomechanical properties of the rod-screw prosthesis based on a pelvic three-dimensional finite element model including muscle and ligament, and evaluate the effectiveness of zoneⅠ+Ⅱ+Ⅲ reconstruction of hemipelvis with rod-screw prosthesis in combination with clinical applications. Methods A total of 21 patients who underwent hemipelvic tumor resection (zoneⅠ+Ⅱ+Ⅲ) and rod-screw prosthesis reconstruction between January 2015 and December 2020 were selected as the research subjects. Among them, there were 11 males and 10 females; the age ranged from 16 to 64 years, with an average age of 39.2 years. There were 9 cases of chondrosarcoma, 7 cases of osteosarcoma, 3 cases of Ewing sarcoma, and 2 cases of undifferentiated pleomorphic sarcoma. According to the Musculoskeletal Tumor Society Score (MSTS) staging, there were 19 cases of stage ⅡB and 2 cases of stage Ⅲ. Preoperative Harris Hip Score (HHS) and MSTS score were 54.4±3.1 and 14.1±2.0, respectively. Intraoperative 15 cases underwent extensive resection, 5 cases underwent marginal resection, and 1 case underwent intralesional resection. The CT image of 1 patient after reconstruction was used to establish a three-dimensional solid model of the pelvis via Mimics23Suite and 3-matic softwares. At the same time, a mirror operation was used to obtain a normal pelvis model, then the two solid models were imported into the finite element analysis software Workbench 2020R1 to establish three-dimensional finite element models, and the biomechanical properties of the standing position were analyzed. The operation time, intraoperative blood loss, and operation-related complications were recorded, and the postoperative evaluation was carried out with HHS and MSTS scores. Finally, the local recurrence and metastasis were reviewed. ResultsFinite element analysis showed that the peak stress of the reconstructed pelvis appeared at the fixed S1, 2 rod-screw connections; the peak stress without muscles was higher than that after muscle construction, but much smaller than the yield strength of titanium alloy. The operation time was 250-370 minutes, with an average of 297 minutes; the amount of intraoperative blood loss was 3 200-5 500 mL, with an average of 4 009 mL. All patients were followed up 8-72 months, with an average of 42 months. There were 7 cases of pulmonary metastasis, of which 2 cases were preoperative metastasis; 5 cases died, 16 cases survived, and the 5-year survival rate was 72.1%. There were 3 cases of local recurrence, all of whom did not achieve extensive resection during operation. The function of the affected limbs significantly improved, and the walking function was restored. The HHS and MSTS scores were 75.2±3.0 and 20.4±2.0 at last follow-up, respectively, and the differences were significant when compared with those before operation (t=22.205, P<0.001; t=11.915, P<0.001). During follow-up, 2 cases of delayed incision healing, 2 cases of deep infection, 1 case of screw loosening, and 1 case of prosthesis dislocation occurred, and no other complication such as prosthesis or screw fracture occurred. Conclusion The stress and deformation distribution of the reconstructed pelvis are basically the same as normal pelvis. The rod-screw prosthesis is an effective reconstruction method for pelvic malignant tumors.