Lijing Deng, Xingyi Zhou, Zhifang Lan, Kairui Tang, Xiaoxu Zhu, Xiaowei Mo, Zongyao Zhao, Zhiqiang Zhao, and Mansi Wu. J. Microbiol. Biotechnol. 2022;32:405-18. https://doi.org/10.4014/jmb.2110.10018

Objective: Treating pediatric osteosarcoma in long bones is challenging due to skeletal immaturity, which restricts the generalizability of insights derived from adult patients. Are there disparities in outcomes? How should surgical protocols be tailored for children of varying ages? What are the specific postoperative complications? A large single-center retrospective cohort study of 345 patients under 14 years old with lower-limb osteosarcoma treated in our department since 2000 was conducted to address these inquiries. Methods: A retrospective analysis of 345 pediatric patients with lower-limb osteosarcoma admitted to our department between 2000 and 2019 was conducted. Clinical and functional outcomes were compared based on age groups, surgical methods, type of prosthesis, and primary tumor location. Patients were divided into the low-age group (≤10 y old) and the high-age group (>10 y old). Overall survival rate (OS), progressionfree survival rate (PFS), and prosthesis survival rate were assessed using Kaplan–Meier curves, nonparametric survival analysis (log-rank test), and Univariate cox regression were used for comparison. The incidence of complications, local relapse rate (LRR), metastasis rate, final limb-salvage, and amputation rate, and Musculoskeletal Tumor Society (MSTS) score of different independent groups were further evaluated using χ ² test or Fisher’s exact test, and t-test was employed to evaluate the measurement data. Results: The average age of the patients was 11.10±2.32 years ranging from 4 to 14 y, with an average follow-up duration of 48.17 months. The 5, 10, and 15-year OS rates were 50.3%, 43.8%, and 37.9%, respectively. The progression-free survival rate was 44.8% at 5 years and 41.1% at 10 years. The final limb salvage rate was 61.45%, while the final amputation rate was 38.55%. The low-age group had a higher amputation rate compared with the high-age group (48.00% vs. 33.18%, P=0.009). The overall LRR was 9.28%, and the incidence of metastasis was 28.99%. The LRR of the limb-salvage group was higher than the amputation group (P=0.004). The low-age group experienced more prosthesis-related complications than the high-age group (P=0.001). The most common prosthesis-related complication in the low-age group was soft-tissue failure, while the periprosthetic infection was most frequent in the high-age group. The high-age group had a higher cumulative prosthesis survival compared with the low-age group (P=0.0097). Modular prosthesis showed better MSTS scores and higher cumulative prosthetic survival than expandable prosthesis in pediatric patients (P<0.05). Conclusion: Limb preservation in pediatric patients becomes increasingly efficacious with advancing age, while consideration of amputation is warranted for younger patients. The prevailing postoperative complications associated with prosthesis encompass soft tissue failure and periprosthetic infection. Younger patients diagnosed with lower limb osteosarcoma exhibit a heightened amputation rate and a greater incidence of prosthesis-related complications.

Objectives: Over the past three decades, orthopedic surgical robots have experienced rapid advancements. This study, a case series, aimed to investigate the effectiveness, limitations, and technical improvements associated with the application of robots in the surgical treatment of bone tumors. Methods: From November 2021 to October 2023, 54 patients with bone tumors who provided consent for robot‐assisted surgery were included. Patients were divided into three groups based on specific objectives: robot‐assisted path planning, pedicle screw insertion, and intraoperative real‐time navigation‐assisted tumor resection. Perioperative conditions were meticulously recorded for all patients, including intraoperative blood loss, operation duration, postoperative complications, and tumor diameter. Results: Nineteen patients underwent robot‐assisted tissue biopsies, and pathological examinations confirmed a positive rate of 84.21%. Among the 21 patients undergoing robot‐assisted pedicle screw placement, surgical planning was executed with high accuracy. Twenty patients undergoing robot‐assisted lesion excision achieved precise resection of the tumor‐affected bone segments as planned preoperatively, and no secondary osteotomies were required. No perioperative complications related to the use of robots were observed in the 54 patients. To address the limitation of orthopedic robots in differentiating soft tissues, we integrated ultrasound technology and the da Vinci robot. Additionally, patient‐specific cutting guides were utilized to compensate for the prolonged operation time associated with planar planning using orthopedic robots. Conclusions: Robot‐assisted technology facilitates the precise planning of the surgical path and determination of the osteotomy plane. The integration of orthopedic robots with intraoperative ultrasound or Da Vinci robots can potentially further ensure the safety of bone tumor surgery while maintaining its accuracy, thereby minimizing the risk of complications associated with surgical procedures. Furthermore, this technology combined with patient‐specific cutting guides may be conducive to reducing operation time.

Background: At present, amputation was widely adopted for young patients when limb salvage was deemed risky with several surgical strategy such as rotationplasty. However, leg length discrepancies and unfavorable cosmetic results were indispensable complication of this strategy. The purpose of this study was to propose a novel reconstruction strategy and evaluate the early clinical and functional outcomes of the strategy. Methods: Plastic lengthening amputation (PLA) has been developed by lengthening the stump to preserve one additional distal joint for fixing the artificial limb well. The surgical technique and postoperative management were documented, and the functional outcomes were compared with those of traditional amputation (TA). Six pairs of patients matched for age, sex, location, pathological type, and final prosthesis underwent individually designed plastic lengthening amputation with vascularized autografts or traditional amputation between January 2005 and December 2007. All patients were followed, and the locomotor index and the musculoskeletal tumor society score (MSTS) were used to describe and quantitatively grade limb functional outcomes after amputation. The complications and functional outcomes of the patients taken two kinds of procedures were compared. Results: Twelve patients with osteosarcoma or Ewing’s sarcoma of either the femur or tibia were included in the study. Six patients underwent plastic lengthening amputations, three of whom also underwent vascular anastomosis. Patients were followed for an average of 48.17 months; bone healing required an average of 3.3 months. No local recurrence was found. The average postoperative locomotor index functional score of the affected limb was 32.67 ± 5.89 in the plastic lengthening amputation group while was 19.50 ± 7.87 in the traditional amputation group. The MSTS functional scores were 22.67 ± 1.33 and 24.17 ± 1.45 at 6 and 12 months for patients in PLA group while 17.00 ± 1.549 and 17.83 ± 1.64 at 6 and 12 months for patients in TA group. Conclusions: Plastic lengthening amputations with vascularized autografts could preserve the knee joint to improve the function of the amputated limb in selected bone sarcoma patients.

Background: To review and study 14 cases of phosphaturic mesenchymal tumor (PMT) patients, integrating previous literature to expand understanding of this disease, improve diagnosis rates, and enhance treatment efficacy. Methods: This study included 14 patients with PMT who were treated and pathologically confirmed at our bone tumor center between December 2016 and September 2023. Clinical data, including imaging, pathological findings, and laboratory results, were collected and analyzed. All patients underwent preoperative PET/CT scanning, followed by surgery, and were monitored during an average postoperative follow-up period of 28.86 ± 21.72 months. The surgical procedures included tumor resection, curettage, and ablation. Results: The study cohort comprised 10 males and 4 females. Tumor locations included the femur (6 cases), tibia (3 cases), humerus (1 case), fibula (2 cases), ilium (1 case), and the posterior edge of the right deltoid muscle (1 case). The average tumor size was 3.6 ± 1.3 cm. Most patients exhibited systemic osteomalacia, with 11 patients experiencing multiple rib fractures and an average preoperative disease duration of 29.04 ± 22.83 months. All patients demonstrated varying degrees of hypophosphatemia and elevated alkaline phosphatase levels, with PET/CT scans revealing increased FDG/DOTANOC uptake in the lesions. Postoperative follow-up indicated that patients who underwent tumor resection showed superior improvements in blood phosphorus levels and bone density compared to those who underwent curettage or ablation. The Musculoskeletal Tumor Society (MSTS) scores of all patients significantly improved postoperatively, increasing from a preoperative mean of 20.22 ± 3.44 to a postoperative mean of 28.38 ± 1.05 ( P < 0.05). Conclusion: PMT is a rare and challenging mesenchymal tumor to diagnose due to its nonspecific symptoms and low incidence. The combination of DOTANOC-PET/CT imaging and postoperative pathological examination provides a reliable diagnostic approach. Among the surgical options, tumor resection has demonstrated superior efficacy in improving both biochemical markers and clinical outcomes, making it the preferred treatment method over tumor curettage or ablation. Level of evidence: Level IV, therapeutic study.