[Effectiveness evaluation of three-dimensional printed customized hemi-pelvic prosthesis for pelvic reconstruction after resection of massive pelvic tumor].

OBJECTIVE: To investigate the effectiveness of three-dimensional (3D) printed customized hemi-pelvic prosthesis for pelvic reconstruction after resection of massive pelvic tumors.

METHODS: A retrospective analysis was conducted on 26 patients with massive pelvic tumors who met the selection criteria and were treated between November 2021 and May 2024. The cohort included 11 males and 15 females, with a mean age of 52.65 years (range, 17-73 years). Histopathological diagnoses were as follows: 9 cases of chondrosarcoma, 2 of undifferentiated pleomorphic sarcoma, 4 of spindle cell sarcoma, 2 of osteosarcoma, 1 of solitary fibrous tumor, 1 of myxoid chondroma, 1 of malignant peripheral nerve sheath tumor, 1 of chondromyxoid epithelioma, and 5 of metastatic malignant tumors. According to the Enneking classification, tumor involvement was distributed as 4 cases in zones Ⅰ+Ⅱ, 9 in zones Ⅱ+Ⅲ, 3 in zones Ⅰ+Ⅳ, 8 in zones Ⅰ+Ⅱ+Ⅲ, and 2 in zones Ⅰ+Ⅱ+Ⅳ. The disease duration ranged from 3 to 40 months, with a mean of 9.85 months. All patients underwent reconstruction with customized 3D-printed hemi-pelvic prostheses. The effectiveness was evaluated by Musculoskeletal Tumor Society (MSTS) score and Harris hip score before operation and at last follow-up, and pain levels were evaluated by visual analogue scale (VAS) score before operation, at 3 months after operation, and at last follow-up.

RESULTS: The operation time ranged from 186 to 528 minutes, with a mean of 334.58 minutes. The intraoperative blood loss ranged from 1 400 to 4 000 mL, with a mean of 2173.08 mL, and the transfusion volume ranged from 750 to 3 500 mL, with a mean of 1 659.62 mL. All 26 patients were followed up 10-42 months (mean, 18.5 months). Postoperative complications included prosthetic dislocation in 2 cases, which were attributed to improper positioning during home care and an accidental fall, respectively. One patient developed a vesicocutaneous fistula and poor wound healing due to pre-existing tumor invasion into the bladder. One patient experienced failure and loosening of the internal fixation at 8 months after operation caused by local tumor recurrence, and subsequently died at 14 months postoperatively due to progression of brain metastases. Postoperative complications such as poor healing of incisions, prosthetic dislocation, or failure of internal fixation was not observed in the remaining patients. At last follow-up, the walking ability of most patients recovered to varying degrees. The VAS scores at 3 months and at last follow-up significantly improved when compared with those before operation, and the scores at last follow-up further improved when compared with 3 months after operation, all showing significant differences ( P<0.05). The MSTS scores and Harris scores at last follow-up were significantly higher than those before operation ( P<0.05).

CONCLUSION: 3D printed customized hemi-pelvic prosthesis is effective for reconstruction of massive pelvic tumors after resection, but there are still some limitations, and soft tissue reconstruction should be paid attention to.