Two-step osteotomy/discectomy through cannulated screw (TOCS) technique for en bloc resection of spine tumor: surgical technique and preliminary results.

PURPOSE: We have developed a novel technique for osteotomy/discectomy during en bloc resection of spine tumors named two-step osteotomy/discectomy through cannulated screw (TOCS). This study aims at describing the procedure of TOCS technique and assessing its efficiency and safety. METHODS: We retrospectively reviewed fourteen patients who underwent en bloc resection for spine tumors using TOCS technique in our center between August 2018 and September 2022. The technique was based on a specially designed "slotted" cannulated screw which was a cannulated screw with a longitudinal slot to provide the accessibility of T-saw. During osteotomy/discectomy, the "slotted" cannulated screw was inserted obliquely along the plane between the dura and the posterior wall of spine in light of the planned osteotomy/discectomy plane under routine fluoroscopic imaging guidance. The T-saw was introduced through the screw, and the osteotomy/discectomy was performed sequentially in two steps under the guidance of the screw by turning the slot away and toward the dura. The intra-/perioperative complication, neurological function (determined by Frankel grading), surgical margin (determined by a pathologist using AJCC R system), follow-up details were documented. RESULTS: The mean duration of surgery was 599.3 (360-890) min with a mean volume of intra-operative hemorrhage of 2021.4 (800-5000) mL. The intra-/perioperative complications were found in four patients (28.6%). R0 and R1 resections were achieved in nine and five patients, respectively. There was no R2 resection. After a mean follow-up period of 30.6 (10-67) months, all patients were alive except one patient died ten months after surgery due to unrelated cause. No recurrence and implant failure were found. Thirteen patients (92.9%) exhibited completely normal neurological function same as their preoperative neurological status. CONCLUSION: Using TOCS technique can facilitate a precise, complete and safe osteotomy/discectomy procedure during en bloc resection for spine tumor without the aid of intra-operative navigation.

Functional analysis of a rice 12-oxo-phytodienoic acid reductase gene (OsOPR1) involved in Cd stress tolerance.

BACKGROUND: The accumulation of cadmium (Cd) in plants may compromise the growth and development of plants, thereby endangering human health through the food chain. Understanding how plants respond to Cd is important for breeding low-Cd rice cultivars. METHODS: In this study, the functions of 12-oxo-phytodienoic acid reductase 1 (OsOPR1) were predicted through bioinformatics analysis. The expression levels of OsOPR1 under Cd stress were analyzed by using qRT-PCR. Then, the role that OsOPR1 gene plays in Cd tolerance was studied in Cd-sensitive yeast strain (ycf1), and the Cd concentration of transgenic yeast was analyzed using inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: Bioinformatics analysis revealed that OsOPR1 was a protein with an Old yellow enzyme-like FMN (OYE_like_FMN) domain, and the cis-acting elements which regulate hormone synthesis or responding abiotic stress were abundant in the promoter region, which suggested that OsOPR1 may exhibit multifaceted biological functions. The expression pattern analysis showed that the expression levels of OsOPR1 were induced by Cd stress both in roots and roots of rice plants. However, the induced expression of OsOPR1 by Cd was more significant in the roots compared to that in roots. In addition, the overexpression of OsOPR1 improved the Cd tolerance of yeast cells by affecting the expression of antioxidant enzyme related genes and reducing Cd content in yeast cells. CONCLUSION: Overall, these results suggested that OsOPR1 is a Cd-responsive gene and may has a potential for breeding low-Cd or Cd-tolerant rice cultivars and for phytoremediation of Cd-contaminated in farmland.

Expression of OsHARBI1-1 enhances the tolerance of Arabidopsis thaliana to cadmium.

BACKGROUND: As one of the major food crops in the world, rice is vulnerable to cadmium (Cd) pollution. Understanding of the molecular mechanisms of Cd uptake, transport and detoxification in rice is essential for the breeding of low-Cd rice. However, the molecular mechanisms underlying the response of rice to Cd stress remains to be further clarified. RESULTS: In this study, a novel Cd-responsive gene OsHARBI1-1 was identified in the rice genome and its expression pattern and function were characterized. Bioinformatics analysis showed that the promoter region of OsHARBI1-1 had multiple cis-acting elements in response to phytohormones and stress, and the expression of OsHARBI1-1 was induced by phytohormones. OsHARBI1-1 protein was targeted to the nucleus. qRT-PCR analysis results showed that the expression of OsHARBI1-1 in the roots was repressed while the expression in the shoots was increased under Cd stress. Heterologous expression of OsHARBI1-1 in yeast conferred tolerance to Cd and reduced Cd content in the cells. Meanwhile, the expression of OsHARBI1-1 in Arabidopsis thaliana (A. thaliana) enhanced the tolerance of A. thaliana to Cd stress. In addition, compared with the wild type plants, the POD activity of transgenic plants was increased, while the SOD and CAT activities were decreased. Interestingly, the accumulation of Cd in the roots of A. thaliana expressing OsHARBI1-1 was significantly increased, whereas the Cd accumulation in the shoots was slightly decreased. Compared to the WT plants, the expression of genes related to Cd absorption and chelation was upregulated in transgenic A. thaliana under Cd stress, while the expression of genes responsible for the translocation of Cd from the roots to the shoots was downregulated. Moreover, the expression of phytohormone-related genes was significantly influenced by the expression of OsHARBI1-1 with and without Cd treatment. CONCLUSIONS: Findings of this study suggest that OsHARBI1-1 might play a role in the response of plants to Cd response by affecting antioxidant enzyme activities, Cd chelation, absorption and transport, and phytohormone homeostasis and signaling.

OsHIPP17 is involved in regulating the tolerance of rice to copper stress.

Introduction: Heavy metal-associated isoprenylated plant proteins (HIPPs) play vital roles in metal absorption, transport and accumulation in plants. However, so far, only several plant HIPPs have been functionally analyzed. In this study, a novel HIPP member OsHIPP17, which was involved in the tolerance to copper (Cu) was functionally characterized. Methods: In this study, qRT-PCR, Yeast transgenic technology, Plant transgenic technology, ICP-MS and so on were used for research. Results: OsHIPP17 protein was targeted to the nucleus. The Cu concentration reached 0.45 mg/g dry weight due to the overexpression of OsHIPP17 in yeast cells. Meanwhile, the overexpression of OsHIPP17 resulted in the compromised growth of Arabidopsis thaliana (Arabidopsis) under Cu stress. The root length of Oshipp17 mutant lines was also significantly reduced by 16.74- 24.36% under 25 mM Cu stress. The roots of Oshipp17 rice mutant showed increased Cu concentration by 7.25%-23.32%. Meanwhile, knockout of OsHIPP17 decreased the expression levels of OsATX1, OsZIP1, OsCOPT5 or OsHMA5, and increased the expression levels of OsCOPT1 or OsHMA4. Antioxidant enzyme activity was also reduced in rice due to the knockout of OsHIPP17. Moreover, the expression levels of cytokinin-related genes in plants under Cu stress were also affected by overexpression or knockout of OsHIPP17. Discussion: These results implied that OsHIPP17 might play a role in plant Cu toxic response by affecting the expression of Cu transport genes or cytokinin-related genes. Simultaneously, our work may shed light on the underlying mechanism of how heavy metals affect the plant growth and provide a novel rice genetic source for phytoremediation of heavy metal-contaminated soil.

Metallochaperone protein OsHIPP17 regulates the absorption and translocation of cadmium in rice (Oryza sativa L.).

Heavy metal-associated isoprenylated plant proteins (HIPPs) play vital roles in regulating heavy metal responding activities in plants. Yet only a handful of studies have characterized the functions of HIPPs. In this study, a novel HIPP member OsHIPP17 was functionally characterized, which was involved in the tolerance of yeast and plants to cadmium (Cd). The Cd accumulation in yeast cells was increased due to the overexpression of OsHIPP17. Nevertheless, the overexpression of OsHIPP17 in Arabidopsis thaliana resulted in compromised growth under Cd stress. Meanwhile, the mutation of OsHIPP17 resulted in 38.9-40.9 % increase of Cd concentration in rice roots as well as 14.3-20.0 % decrease of Cd translocation factor. Further investigation of the genes responsible for Cd absorption and transporter indicated that the expression levels of these genes were also perturbed. In addition, two OsHIPP17-interacting proteins, OsHIPP24 and OsLOL3 were identified in a yeast two hybrid assay. Further analysis of their functions revealed that OsHIPP24 or OsLOL3 may be involved in the regulation of Cd tolerance by OsHIPP17 in rice. All above results implied that OsHIPP17 may affect Cd resistance by regulating the absorption and translocation of Cd in rice.

Bioinformatic and functional analysis of OsDHN2 under cadmium stress.

As a toxic heavy metal, cadmium (Cd) is one of the principal pollutants influencing rice productivity and food security. Despite several studies, the underlying mechanism of Cd response in plants remains largely unclear. Dehydrins are part of the late embryogenesis abundant (LEA) family which protect plants against abiotic stresses. In this study, a Cd-responsive LEA gene, OsDHN2, was functionally characterized. The chromosome localization results indicated that OsDHN2 was located on chromosome 2 of rice. Meanwhile, cis-acting elements, such as MBS (MYB binding site involved in drought-inducibility), ARE (anaerobic induction), and ABRE (abscisic acid), were present in the OsDHN2 promoter region. Expression pattern analysis also showed that OsDHN2 expression was induced in both roots and shoots under Cd stress. Overexpression of OsDHN2 improved Cd tolerance and reduced Cd concentration in yeast. Moreover, increased expression levels of SOD1, CTA1, GSH1, or CTT1 were found in transgenic yeast under Cd stress, suggesting the increased antioxidant enzymatic activities. These results suggested that OsDHN2 is a Cd-responsive gene that has the potential to improve resistance to Cd in rice.

Distinct genomic features between osteosarcomas firstly metastasing to bone and to lung.

Background: Osteosarcoma initially metastasing to bone only shows distinct biological features compared to osteosarcoma that firstly metastasizes to the lung, which suggests us underlying different genomic pathogenetic mechanism. Methods: We analyzed whole-exome sequencing (WES) data for 38 osteosarcoma with paired samples in different relapse patterns. We also sought to redefine disease subclassifications for osteosarcoma based on genetic alterations and correlate these genetic profiles with clinical treatment courses to elucidate potential evolving cladograms. Results: We investigated WES of 12/38 patients with high-grade osteosarcoma (31.6%) with initial bone metastasis (group A) and 26/38 (68.4%) with initial pulmonary metastasis (group B), of whom 15/38 (39.5%) had paired samples of primary lesions and metastatic lesions. We found that osteosarcoma in group A mainly carries single-nucleotide variations displaying higher tumor mutation burden and neoantigen load and more tertiary lymphoid structures, while those in group B mainly exhibits structural variants. High conservation of reported genetic sequencing over time in their evolving cladograms. Conclusions: Osteosarcoma with mainly single-nucleotide variations other than structural variants might exhibit biological behavior predisposing toward bone metastases as well as better immunogenicity in tumor microenvironment.

Reconstruction With a 3D-Printed Megaprosthesis With Ankle Arthrodesis After Distal Tibial Tumor Resection.

BACKGROUND: Reconstruction after en bloc resection of the distal tibia has remained an unsettled issue despite many attempts with bone grafts or prostheses in the past. Failures of the previous methods have been attributed to inadequate mechanical strength, poor articular stability, failed osseointegration, and poor soft tissue coverage. To overcome these shortcomings, we designed and applied a 3D-printed megaprosthesis with ankle arthrodesis. METHODS: A total of 13 patients underwent resection of a distal tibial tumor and reconstruction with a 3D-printed distal tibial megaprosthesis between January 2017 and November 2020. Mean age was 14.9±6.5 years. Diagnoses included 11 cases of osteosarcoma and 1 case each of low-grade phosphaturic mesenchymal tumor and rhabdomyosarcoma. Baseline characteristics, operative data, complication profiles, and oncologic, and functional outcomes were reviewed and analyzed. RESULTS: All 13 cases attained a wide or marginal resection. During a mean follow-up of 26.8±10.6 months, 1 patient experienced local recurrence and distant metastasis, whereas 3 other patients only developed distant metastasis. Periprosthetic infection subsequent to paronychia occurred in 1 patient 24 months after the operation. No other complications were observed. By the last follow-up, the mean MSTS-93 score was 28.0±1.5. CONCLUSION: In this relatively small cohort with short-term follow-up, reconstruction with the 3D-printed megaprosthesis with ankle arthrodesis was found to be a safe and efficacious method after resection of a distal tibial malignancy.

Elbow hemiarthroplasty with a 3D-printed megaprosthesis for defects of the distal humerus or proximal ulna after tumour resection : a preliminary report.

AIMS: The aim of this study was to investigate the feasibility of application of a 3D-printed megaprosthesis with hemiarthroplasty design for defects of the distal humerus or proximal ulna following tumour resection. METHODS: From June 2018 to January 2020, 13 patients with aggressive or malignant tumours involving the distal humerus (n = 8) or proximal ulna (n = 5) were treated by en bloc resection and reconstruction with a 3D-printed megaprosthesis with hemiarthroplasty, designed in our centre. In this paper, we summarize the baseline and operative data, oncological outcome, complication profiles, and functional status of these patients. RESULTS: Preparation of the prosthesis was a mean of 8.0 days (SD 1.5), during which time no patients experienced tumour progression. The mean operating time and intraoperative blood loss were 158.1 minutes (SD 67.6) and 176.9 ml (SD 187.8), respectively. All of the prostheses were implanted successfully. During a mean follow-up of 25.7 months (SD 7.8), no patients died, but four had complications (two superficial wound problems, one temporary palsy of radial nerve, and one dislocation). No aseptic loosening, structural failure, infection, heterotopic ossification, or degenerative arthritis was seen in this study. The mean flexion of the elbow was 119.6° (SD 15.9°) and the mean extension lag was 11.9° (SD 13.8°). The mean Musculoskeletal Tumor Society 93 score and Mayo Elbow Performance Score were 28.4 (SD 0.9) and 97.7 (SD 4.4), respectively. CONCLUSION: The custom-made, 3D-printed megaprosthesis with hemiarthroplasty is a feasible option for functional reconstruction after resection of a tumour in the distal humerus or proximal ulna. Cite this article: Bone Joint J 2022;104-B(6):747-757.

Ultra-Short Course of Neo-Adjuvant Denosumab for Nerve-Sparing Surgery for Giant Cell Tumor of Bone in Sacrum.

STUDY DEIGN: This was a retrospective study about sacral giant cell tumor of bone (GCTB). OBJECTIVE: This study aimed to investigate whether ultra-short course of neo-adjuvant denosumab treatment for sacral GCTB could (1) induce radiological and histological response? (2) Facilitate nerve-sparing surgery? (3) Achieve satisfactory oncological and functional outcomes? SUMMARY OF BACKGROUND DATA: Previous reports on long course of neo-adjuvant denosumab treatment for GCTB showed significant tumor response and a relatively high recurrent rate after curettage. METHODS: Sixty-six patients with sacral GCTB treated with neoadjuvant denosumab and nerve-sparing surgery were categorized into ultra-short course group (≤3 doses and operation within D21 since 1st dose, 41 patients) or conventional group (>3 doses or operation after D21 since 1st dose, 25 patients). The radiological and histological response, operative data, oncological and functional outcomes were compared. RESULTS: The ultra-short course group demonstrated fewer doses of neo-adjuvant denosumab (mean: 2.1 vs. 4.8, P  < 0.001) and shorter time to surgery (12.2 days vs. 72.3 days, P < 0.001). Similar patterns of radiological and histological response were observed in the two groups with less fibrosis and ossification in the ultra-short course group. The operative duration (199.9 min vs. 187.8 min, P = 0.364) and estimated blood loss (1552.4 mL vs. 1474.0 mL, P = 0.740) were comparable. Most (94.8%) of the patients received adjuvant denosumab. After a mean follow-up of 29.4 months, three cases (8.8%) and five cases (20.8%) showed local recurrence in each group (P = 0.255). The estimated recurrence-free survival (56.2 vs. 51.2 months, P = 0.210) and the functional status [Motor-Urination-Defecation scores: 25.9 vs. 25.7, P = 0.762] did not differ between the two groups. CONCLUSION: Ultra-short course of neo-adjuvant denosumab for sacral GCTB could elicit radiological and histological responses as conventional course did. The less degree of fibrosis and ossification might facilitate nerve-sparing surgery and help to achieve satisfactory local control and functional status.Level of Evidence: 4.

Analysis for clinical feature and outcome of chondroblastoma after surgical treatment: A single center experience of 92 cases.

BACKGROUND: Chondroblastoma is a rare, benign, cartilaginous bone tumor derived from epiphyseal chondrocytes. Although the clinical characteristics and experience of surgical treatment of the smaller number of patients has been reported in the literature, it is difficult to draw conclusions about the clinical and radiographic features and the outcome for surgical treatment of this disease due to the rarity of chondroblastoma. This study was aiming to review the epidemiologic characteristics and outcome of surgical management for patients with chondroblastoma. METHODS: We performed a retrospective analysis of 92 patients with chondroblastoma. Clinical data, radiographic images, surgical treatment and outcome were analyzed. Eighty-two patients received the extensive intralesional curettage and ten cases had the En-block resection. RESULTS: The most common site of disease was proximal femur (20.7%, 19/92), followed by distal femur (18.5%, 17/92) and proximal tibia (16.3%, 15/92). The secondary aneurysmal bone cyst component was most common for chondroblastoma of the small irregular bones, such as patella and foot. Four (4.3%, 4/92) cases receiving the extensive intralesional curettage developed the local recurrence, respectively two at the proximal tibia, one at the pelvis and one at the calcaneus. Time to local recurrence were respectively 14.5, 8.8, 27.0 and 5.6 months, with the average 14 months. Kaplan-Meier estimated survivorship curve of local recurrence-free survival rates of one, two and five years were respectively 97.7%, 96.2% and 93.9%. The mean Musculoskeletal Tumor Society (MSTS) score was 29.4. At the last follow-up, no one had the pulmonary metastasis and death associated with the disease. CONCLUSION: Intralesional curettage plus local adjuvants can obtain satisfactory outcome for chondroblastoma. LEVEL OF EVIDENCE: Level IV.

Analysis of mechanical complications for patients with extremity sarcoma after biological reconstruction.

BACKGROUND: Biological reconstruction after tumor resection is significant for restoration of limb integrality. However, it is unclear what risk factors influence mechanical complications of patients after extremity sarcoma resection and biological reconstruction. The objective of study was (1) to compare complications between patients receiving inactivated autograft and allograft, (2) to analyze influence of graft type, nonunion and fixation method on mechanical complications for patients after biological reconstruction. HYPOTHESIS: We hypothesized allograft, nonunion and fixation method influence occurrence of mechanical complications after biological reconstruction. MATERIALS AND METHODS: We retrospectively reviewed 71 patients with sarcomas at the extremity receiving biological reconstruction from January 1999 to November 2015. Eight patients were lost at last follow-up. Sixty-three patients with complete clinical data were recruited into the present study. There were 32 males and 31 females with a mean age of 20.5±14.9 years (median, 17 years; range, 2-72 years). Sixty-one cases had tumors at lower extremity and two at upper extremity. Histological diagnosis was confirmed as forty-five with osteosarcoma, thirteen with Ewing sarcoma and five with chondrosarcoma. RESULTS: Forty-four patients were free of disease, sixteen died of disease and three lived with pulmonary metastasis at last follow-up. Twenty-one out of 63 patients (33.3%) had local recurrence requiring surgical treatment. Reconstruction choice (mechanical complications rates were 38.9% for allograft (14/36) versus 14.8% for inactivated autograft (4/27)) and nonunion occurrence (yes 58.8% (10/17); no 17.4% (8/46)) had the close relationship with mechanical complication in the univariate analysis. The multivariate analysis revealed fixation method (p=0.041) and nonunion (p=0.008) were prognostic factors for mechanical complication of sarcoma resection and biological reconstruction at the extremity. Fourteen of 36 patients receiving massive allograft had a second surgery due to mechanical complication compared to 4 of 27 patients with massive inactivated autograft (38.9%, 14/36 vs. 14.8%, 4/27 (p=0.05)). Time to union for diaphysis and metaphysis was not significantly different between allograft and inactivated autograft groups. DISCUSSION: Patients receiving massive allograft are prone to suffer from the mechanical complications. Extramedullary plate and nonunion have the tendency of increasing occurrence of mechanical complications of biological reconstruction. LEVEL OF EVIDENCE: IV; retrospective study.

[Formins: the key regulators of plant cell morphology and development].

Formins are widely distributed in eukaryotes such as fungi, plants and animals. They play crucial roles in regulating the polymerization of actin, coordinating the synergistic interactions between actin and microtubules, and determining cell growth and morphology. Unlike formins from fungi and animals, plant formins have been evolved into two plant-specific types. Generally, type Ⅱ formins are believed to regulate the polarized growth of cells, and type Ⅰ formins may regulate the cell expansion and division processes. Recent studies on the function of plant formins suggest it is inappropriate to classify the function of formins purely based on their structures. This review summarizes the domain organization of formins and their corresponding functions, as well as the underpinning mechanisms. Furthermore, the unsolved or unexplored issues along with future perspectives on plant formins are proposed and discussed.

Status and prospects of the application of root exudates in the restoration of polluted or desertated soil.

Ecological and environmental problems including heavy metal pollution have received increasing concerns. Given the shortage of physical and chemical remediation methods in high cost and secondary pollution, using plants and microorganisms for joint remediation of environment has become one of the most important strategies. Root exudates are an important medium for information and nutrient exchange between plants and soil. The roles of plant root exudates in remediation of polluted and degradated soil have been widely studied. In this review, we described the composition, secretion mechanism and functions of root exudates and summarized the functions of root exudate in heavy metal absorption, allelopathy, interaction between roots and rhizosphere microorga-nisms, and changes in soil physical and chemical properties. The progress, challenges and prospect of applying root exdudates and rhizosphere microorganisms in the remediation of ecology and environment have also been discussed. This review could provide theoretical support for the application of plant-microorganism based environmental remediation.

Preliminary Results of a 3D-Printed Modular Vertebral Prosthesis for Anterior Column Reconstruction after Multilevel Thoracolumbar Total En Bloc Spondylectomy.

OBJECTIVE: To evaluate preliminary results of a 3D-printed modular prosthesis for spinal reconstruction after multilevel thoracolumbar total en bloc spondylectomy (TES). METHODS: Patients with thoracolumbar spinal tumors treated surgically between January 2016 and April 2019 were included in this retrospective study. A total of 17 male and 10 female patients with a mean age of 42 (range, 15-72) years comprised the sample. The pathological diagnoses included six chondrosarcomas (one of them was mesenchymal chondrosarcoma), six giant cell tumors, three malignant peripheral nerve sheath tumors, two osteosarcomas, two undifferentiated high-grade pleomorphic sarcomas (UPS), two solitary fibrous tumors, one Ewing's sarcoma, one liposarcoma, and four metastatic tumors. Tumors involved 2 levels in 14 patients, 3 levels in seven patients, 4 levels in four patients, 5 levels in one patient, and 6 levels in one patient. A 3D-printed modular prosthesis was used for anterior column reconstruction after TES. All analyses were performed using SPSS version 18.0 (SPSS, Inc., Chicago, IL). Descriptive statistics were used to analyze the demographic data and clinical outcomes. Data forms included mean, standard deviation and range. RESULTS: Under general anesthesia, all patients received TES with an average operative time of 639 (range, 210-1650) min, and the mean blood loss during operation was 4.1 (range, 0.8-13.3) L. Twenty-two patients have been transferred to ICU for a mean time of 3.2 (range, 0-6) d. All patients had follow-up procedures except for one, who died of perioperative complications. Mean time of follow-up was 22 (range, 12-41) months. Local recurrence (19.2%) occurred in two patients with intralesional margin and three patients with marginal margin, respectively. At the end of follow-up, three patients died of disease, eight patients were alive with disease, and 15 patients had no evidence of disease. Average lengths of resected vertebrae and modular prostheses were 71.4 ± 26.5 mm (range, 40-142 mm) and 68.4 ± 23.9 mm (range, 40-132 mm), respectively. In 26 patients with minimum follow-up of more than 1 year, no evidence of internal fixation failure or dislocation of vertebral prosthesis was found. Asymptomatic prosthetic subsidence into adjacent vertebral bodies occurred in 10 patients with a mean length of 1.8 ± 1.0 mm (range, 1-4 mm). The subsidence was seen at proximal end in two patients, distal end in four patients, and both ends in four patients. Eighteen major complications and 14 minor complications were found in 15 patients. All patients fully recovered at 3 or 6 months after operation. At the latest follow-up, in 23 alive patients, 19 can walk independently and two can achieve outdoor activities by walking aid. CONCLUSION: For spinal reconstruction after multilevel thoracolumbar TES, 3D-printed modular vertebral prosthesis is suitable for different length of anterior column reconstruction with less mechanical complications, and can provide a stable environment to maintain or rehabilitate patients' neurological function in short-term follow-up.

Surgical Strategy of Pediatric Benign Sacral Tumors.

BACKGROUND: Primary benign osseous tumors and tumor-like lesions at the sacrum are rare in the pediatric population and exact surgical strategy is still unclear. In this study, we evaluate the outcome for pediatric patients with benign tumors and tumor-like lesions at the sacrum who were receiving surgical treatment according to our proposed surgical strategy and classification. METHODS: We analyzed 49 pediatric patients with sacral benign tumors or tumor-like lesions aged 18 years and below from 2005 to 2018. There were 23 men and 26 women with a mean age of 14.0±3.8 years. Nineteen patients had giant cell tumors (GCTs), 9 aneurysmal bone cysts, 5 osteoblastomas, 5 neurogenic tumors, 3 hemangiomas, 3 teratomas, 2 Langerhans cell histiocytosis, 1 chondroblastoma, 1 fibrous dysplasia, and 1 GCT of tendon sheath. We proposed our surgical plan and surgical classification for pediatric patients with sacral benign tumors or tumor-like lesions. RESULTS: The mean follow-up duration was 6.2 years (range, 1.0 to 18.9 y). GCTs (39%, 19/49) and primary aneurysmal bone cysts (18%, 9/49) are the top 2 common histologic types. Preoperative selective arterial embolization (SAE) was performed in 12 cases and 24 patients received intraoperative aortic balloon occlusion (ABO) as the preoperative surgical plan. Furthermore, according to tumor location at the sacrum, we classified surgical excision of sacral benign tumors and tumor-like lesions into 3 types. Fourteen cases were classified as type I, 27 as type II, 3 as type III, and 5 patients with neurogenic tumors cannot be classified into this surgical classification. Ten patients had wound complications. Two had femoral artery thrombosis because of ABO application. One had mechanical failure. Rate of local recurrence was 16%. Seven patients with GCTs and 1 with neurogenic tumor had local recurrence. No patient died of disease at the last follow-up. For the assessment of neurological function, the rate of neurological dysfunction was 12% (6/49). Four cases had urinary incontinence, 3 fecal incontinence, and 3 had bowel obstruction. Next, univariate analysis for influence of preoperative SAE and intraoperative ABO on complications demonstrated that both of them exerted no significant influence on the occurrence of oncological and nononcological complications. CONCLUSIONS: The proposed surgical strategy can provide an excellent therapeutic effect for pediatric benign tumors and tumor-like lesions at the sacrum. Preoperative SAE and intraoperative ABO can safeguard pediatric patients with high vascularity of benign tumor at the sacrum during the operation. LEVEL OF EVIDENCE: Level IV.

Preoperative Denosumab may increase the Risk of Local Recurrence of Giant-cell Tumor of Bone Treated with Curettage: A Systematic Review and Meta-analysis.

Objective: This systematic review and meta-analysis aimed to determine the effect of preoperative denosumab on the local recurrence of giant-cell tumor of bone (GCTB) treated with curettage. Methods: PubMed, Embase, Cochrane Library, and Web of Science were comprehensively searched. The following data were analyzed using meta-analysis: local recurrence rate of patients receiving denosumab followed by curettage (denosumab group), local recurrence rate of patients receiving curettage only (control group), and a comparison of the local recurrence rates of the two groups. Results: Nine studies that contained 672 patients with GCTB were included in this review. Patients in the denosumab group (preoperative denosumab followed by curettage) had a higher risk of local recurrence compared with those in the control group (curettage only) (odds ratio = 3.04, 95% confidence interval = 1.48-6.22, P < 0.01). The association between preoperative denosumab and local recurrence remained significant in most of the subgroup analyses, except for those with sample sizes < 59 (P = 0.09), sacral GCTB (P = 0.42), and usage of postoperative denosumab (P = 0.38). Conclusions: Preoperative denosumab may increase the risk of local recurrence of GCTB treated with curettage and should be used with caution in the management of GCTB.

Primary aneurysmal bone cyst of sacrum for adolescent: Eleven cases experience and literature review.

The present study is aiming to describe clinical characteristics, surgical flowchart and treatment results of eleven adolescent patients with primary aneurysmal bone cyst (ABC) of sacrum and review in the literature. We retrospectively reviewed eleven young patients with sacral primary ABC, which had the intact clinical and follow-up information at our bone tumor center from 2001 to 2018. The literature review was based on Google Scholar, Medline, EMBASE and Pubmed databases. The search was performed using terms of "aneurysmal bone cyst", "sacral tumor", "sacrum tumor" "spine tumor" and "spinal tumor" for the literature review from 1998 to 2019. There were six male and five female with a mean age of 13 years old at the presentation. The mean follow-up duration was 6.5 years. No patient died of disease and had the pulmonary metastasis. Two patients had wound complications, including onesurgical site infection and one wound dehiscence. No patient had the local recurrence and neurologic deficit. In the literature review, 11 articles were reviewed and 45 cases with sacral primary ABC were included. The rate of local recurrence may be higher than that in our cohort. We proposed our flow chart for preparation of surgery for patients. Preoperative selective arterial embolization and intraoperative aortic balloon occlusion could provide the clear surgical vision and guarantee complete tumor excision by intralesional curettage. Preoperative selective arterial embolization, intraoperative aortic balloon occlusion and complete tumor excision by intralesional curettage can yield satisfactory results with a low rate of recurrence in adolescent patients with a sacral primary ABC.

Increasing serum alkaline phosphatase is associated with bone deformity progression for patients with polyostotic fibrous dysplasia.

BACKGROUND: Fibrous dysplasia (FD) is a rare bone disorder in which normal intramedullary bone is replaced by fibro-osseous tissue, which is complicated by the progression of Shepherd's crook deformity. How to predict the progression of Shepherd's crook deformity is still a challenging for the orthopedic surgeon. METHODS: A total of 159 cases were reviewed in the retrospective study between January 2000 and September 2016. Clinical and monitoring data were collected. We analyzed the correlationship between the bone turnover markers and other parameters (age, gender, FD type, deformity, BMI, and lesion location). RESULTS: Age, gender, lesion location, lesion type, and shepherd's crook deformity had a close relationship with preoperative ALP level in the univariate analysis, and the multivariate analysis showed age, gender, lesion type, and shepherd's crook deformity had the significant relationship with the preoperative serum ALP level. The surgery could remove the bone lesion and suppressed the abnormal bone metabolism. Furthermore, the preoperative ALP level of FD patients with the shepherd's crook deformity was obviously higher than that without deformity, and the preoperative calcium and phosphorus levels of FD patients with deformity were significantly lower than that without deformity. Notably, for some patients with progression of the shepherd's crook deformity during the follow-up, ALP increased to the high level and at that time X-ray showed the shepherd's crook deformity severely progressing. CONCLUSIONS: PFD with higher serum ALP level has obvious tendency to progress severely, and risk factors of progression to the deformity are the condition of bony metabolism and FD type. The deformity of PFD may be related to high speed of bone turnover, which is exactly reflected by the levels of serum ALP and calcium. Evaluation of patients with FD should include a thorough evaluation of calcium/phosphate metabolism and bone turnover.

Analysis of clinical outcome for adolescent patients undergoing conservative nerve-sparing surgery based on the proposed resection classification for sacral giant cell tumor.

The most common of age distribution ranges from second to fourth decade of life and patients with giant cell tumors (GCT) aged less than 18 years is more uncommon. We are aiming to reveal what the conservative nerve-sparing surgery values for adolescent patients with sacral GCT. We retrospectively reviewed 15 adolescent patients with sacral GCT aged