Development and validation of a nomogram for predicting new vertebral compression fractures after percutaneous kyphoplasty in postmenopausal patients.

BACKGROUND: Postmenopausal women face a heightened risk of developing new vertebral compression fractures (NVCFs) following percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fractures (OVCFs). This study aimed to develop and validate a visual nomogram model capable of accurately predicting NVCF occurrence post-PKP to optimize treatment strategies and minimize occurrence. METHODS: This retrospective study included postmenopausal women diagnosed with OVCF who underwent PKP at the Affiliated Hospital of Shandong University of Traditional Chinese Medicine between January 2016 and January 2021. Patient data, including basic information, surgical details, imaging records, and laboratory findings, were collected. The patients were categorized into two groups based on NVCF occurrence within 2 years post-PKP: the NVCF group and the non-NVCF group. Following the utilization of least absolute shrinkage and selection operator (LASSO) regression for feature selection, a nomogram was constructed. Model differentiation, calibration, and clinical applicability were evaluated using receiver operating characteristic (ROC), calibration, and decision (DCA) curve analyses. RESULTS: In total, 357 patients were included in the study. LASSO regression analysis indicated that cement leakage, poor cement diffusion, and endplate fracture were independent predictors of NVCF. The nomogram demonstrated excellent predictive accuracy and clinical applicability. CONCLUSIONS: This study used LASSO regression to identify three independent predictors of NVCF and developed a predictive model that could effectively predict NVCF occurrence in postmenopausal women. This simple prediction model can support medical decision-making and is feasible for clinical practice.

[Research progress of new multifunctional bone cement in bone tumor therapy].

Objective: The research progress of new multifunctional bone cement in bone tumor therapy in recent years was reviewed, in order to provide help for the future research of anti-tumor bone cement. Methods: The related literature on the treatment of bone tumors with new multifunctional bone cement at home and abroad in recent years was extensively reviewed and summarized. Results: The new multifunctional bone cements include those with the functions of photothermotherapy, magnetic thermotherapy, chemoradiotherapy, and antibacterial after operation, which are discussed from the aspects of anti-tumor, drug controlled release, and cytotoxicity. Controlled drug release has been achieved in multifunctional bone cements by adjusting heat and pH or incorporating particles such as chitosan oligosaccharides and γ-cyclodextrin. At present, multifunctional bone cement with hyperthermia, radiotherapy, and chemotherapy has effectively inhibited the local recurrence and distant metastasis of bone tumors. Broadening the application of bone cement for photothermal and magnetic thermal therapy to deeper bone tumors, investigating more precise controlled release of drug-loaded bone cement, and introducing nanoparticles with both thermal conversion and intrinsic enzymatic activities into bone cement for synergistic anti-tumor therapy are promising research directions. Conclusion: The new multifunctional bone cement inhibits bone tumor cells, promotes new bone formation in bone defects, and prevents incision infection after tumor resection. Certain progress has been made in anti-tumor, antibacterial, drug-controlled release, and reduction of cytotoxicity. Expanding the deeper application range of the new multifunctional bone cement, verifying the safety in clinical application, and focusing on the individualized treatment of the new multifunctional bone cement are the problems that need to be solved in the future.

[Effect of acrylic bone cement mixed with calcium sulfate combined with percutaneous kyphoplasty in the treatment of osteoporotic fractures].

OBJECTIVE: To investigate the clinical efficacy of acrylic cement (PMMA) mixed with calcium sulfate combined with percutaneous kyphoplasty (PKP) in the treatment of osteoporotic fracture (OVCF). METHODS: The clinical data of 191 patients with OVCF treated with PKP from January 2020 to March 2021 were retrospectively analyzed. Among them, 82 patients with 94 vertebral bodies were treated with PMMA mixed with calcium sulfate as the observation group, and 109 patients with 125 vertebral bodies were treated with pure PMMA as the control group. Among the 82 patients in the observation group, there were 16 males and 66 females, with a mean age of (75.35±11.22) years old, including 36 thoracic vertebrae and 58 lumbar vertebrae. In the control group, there were 109 patients, 22 males and 87 females, with an average age of (74.51±9.21) years old, including 63 thoracic vertebrae and 62 lumbar vertebrae. The visual analog scale (VAS) before operation and 1 day, 3 months and 1 year after operation were calculated. The Oswestry disability index (ODI), Cobb's angle, vertebral body height and the probability of postoperative bone cement leakage were used to analyze the efficacy of the two groups. RESULTS: All the patients were followed up for more than one year. Compared with the control group, there was no significant difference in operation time, bleeding volume and bone cement injection volume between the two groups(P>0.05), while the leakage rate of bone cement was significantly lower in the observation group (P<0.05). In addition, there was no significant difference in VAS, ODI, Cobb angle, and vertebral body height between the two groups before operation, and 1 day, 3 months, and 1 year after operation (P>0.05), but each index was improved compared with that before operation (P<0.05). CONCLUSION: PMMA mixed with calcium sulfate has equivalent efficacy in treating OVCF than PMMA alone, but can effectively reduce the probability of cement leakage.

Establishment of a novel risk prediction model for recompression of augmented vertebrae at the thoracolumbar junction and modified puncture technique for prevention: a multicenter retrospective study.

OBJECTIVE: Recompression of augmented vertebrae (RCAV) is often seen after percutaneous kyphoplasty (PKP), especially at the thoracolumbar junction. The authors aimed to develop and validate a risk prediction model (nomogram) for RCAV and to evaluate the efficacy of a modified puncture technique for RCAV prevention after PKP for thoracolumbar osteoporotic vertebral fractures (OVFs). METHODS: Patients who underwent PKP for single thoracolumbar OVFs (T10-L2) between January 2016 and October 2020 were reviewed and followed up for at least 2 years. All patients were randomly divided into a training group (70%) and a validation group (30%). Relevant potential data affecting recompression were collected. Predictors were screened by using binary logistic regression analysis to construct the nomogram. Calibration and receiver operating characteristic curves were used to evaluate the consistency of the prediction models. Finally, the efficacy of the modified puncture technique for prevention of RCAV in OVF patients with a preoperative intravertebral cleft (IVC) was further demonstrated through binary logistic regression analysis. RESULTS: Overall, 394 patients were included and 116 of them (29.4%) sustained RCAV. The independent risk factors included decreased bone mineral density, lower level of serum 25-hydroxy vitamin D3, larger C7-S1 sagittal vertical axis (SVA), preoperative IVC, and solid-lump cement distribution. The area under the curve (AUC) of the prediction model was 0.824 in the training group and 0.875 in the validation group patients. The calibration curve indicated the predictive power of this nomogram, with the preoperative IVC having the highest prediction accuracy (AUC 0.705). The modified puncture technique significantly reduced the incidence of RCAV by enhancing bone cement distribution into a sufficiently diffused distribution in OVF patients with preoperative IVC. CONCLUSIONS: The nomogram prediction model had satisfactory accuracy and clinical utility for identification of patients at low and high risk of postoperative RCAV. Patients at high risk of postoperative RCAV might benefit from the target puncture technique and vitamin D supplementation as well as effective antiosteoporotic therapies.

Optimization of an Injectable, Resorbable, Bioactive Cement Able to Release the Anti-Osteoclastogenic Biomolecule ICOS-Fc for the Treatment of Osteoporotic Vertebral Compression Fractures.

Vertebral compression fractures are typical of osteoporosis and their treatment can require the injection of a cement through a minimally invasive procedure to restore vertebral body height. This study reports the development of an injectable calcium sulphate-based composite cement able to stimulate bone regeneration while inhibiting osteoclast bone resorption. To this aim, different types of strontium-containing mesoporous glass particles (Sr-MBG) were added to calcium sulphate powder to impart a pro-osteogenic effect, and the influence of their size and textural features on the cement properties was investigated. Anti-osteoclastogenic properties were conferred by incorporating into poly(lactic-co-glycolic)acid (PLGA) nanoparticles, a recombinant protein able to inhibit osteoclast activity (i.e., ICOS-Fc). Radiopaque zirconia nanoparticles (ZrO2) were also added to the formulation to visualize the cement injection under fluoroscopy. The measured cement setting times were suitable for the clinical practice, and static mechanical testing determined a compressive strength of ca. 8 MPa, comparable to that of human vertebral bodies. In vitro release experiments indicated a sustained release of ICOS-Fc and Sr2+ ions up to 28 days. Overall, the developed cement is promising for the treatment of vertebral compression fractures and has the potential to stimulate bone regeneration while releasing a biomolecule able to limit bone resorption.

[Bone transplantation or biomaterials? : An analysis of 99,863 surgical procedures in orthopedic and trauma surgery in Germany from 2018]. / Knochentransplantation oder Biomaterial? : Eine Analyse von 99.863 Operationen in Orthopädie und Unfallchirurgie aus dem Jahr 2018 in Deutschland.

BACKGROUND: The aims of this study were (1) to analyze the total number of interventions with autologous or allogeneic bone transplantation as well as biomaterials, (2) to investigate the different types of biomaterials, autologous and allogeneic bone transplantations and (3) to analyze the additional use of an antibiotic additive in biomaterials. METHODS: Data were obtained from the Federal Statistical Office for the year 2018. The surgery and procedure codes 5­784 "bone transplantation and transposition" and 5­785 "implantation of alloplastic bone substitutes" were used to analyze the procedure frequency of implantation of biomaterials, such as calcium phosphate ceramics, calcium sulphate, calcium phosphate cements and polymethyl methacrylate as well as autologous and allogeneic bone for defect reconstruction of the extremities and pelvis. RESULTS: In 2018 a total of 99,863 procedures were performed using autografts (54,784, 55%), biomaterials (23,838, 24%) and allografts (21,241, 21%). For both autografts and allografts cancellous bone grafting was used most frequently (77% and 79%, respectively). For biomaterials, ceramics (42%) were used more frequently than bone cements (37%, other biomaterials 21%). In 16,027 cases (67%) with biomaterials no antibiotic supplement was used. Antibiotic supplementation was mainly used for bone cements (6612 cases, 75%). CONCLUSION: In 2018 bone transplants or biomaterials were used in a considerable number of the 99,863 bone defect reconstruction procedures. Autologous bone was used in more than half of the cases (55%), biomaterials in approximately one quarter (24%) and allogenic bone in approximately one fifth (21%). Ceramics (42%) were more often used as biomaterials than cements (37%). The addition of antibiotics was mainly used with cements (75%).

Interventional radiology for treatment of bone metastases.

Therapeutic advances in oncology have led to longer survival in many forms of cancer, including those complicated by bone metastases. When a bone metastasis is painful or when there is a risk of fracture, interventional radiology procedures can be carried out for pain control and/or stabilisation. All of these techniques can be performed under local anaesthesia. Cementoplasty and vertebroplasty are stabilisation procedures consisting in the percutaneous injection of acrylic cement into a lytic bone lesion. The effect on pain can be explained by the consolidation of weakened, fractured or pre-fractured bone, but also to a lesser extent by the toxic, chemical and thermal effect of the cement. Tumour ablation techniques include alcoholisation or thermal ablation (by heat with radiofrequency and microwave or cold by cryoablation). Percutaneous thermal ablation of bone tumours is most often performed as a palliative measure resulting in a significant and lasting reduction in symptoms. Radiofrequency ablation consists in placing needles through which an electrical current passes. Microwave ablation acts by causing very high frequency vibrations of water molecules. Cryoablation releases argon gas at the tip of the needle, forming an "ice ball" effectively destroying tumour cells. Any of these techniques can be combined to radiation therapy, performed before or after radiation. Finally, tumour embolisation can have a goal of pain control, or preparation of surgery to reduce the risk of peroperative haemorrhage.

Autologous Iliac Bone Graft Compared with Biphasic Hydroxyapatite and Calcium Sulfate Cement for the Treatment of Bone Defects in Tibial Plateau Fractures: A Prospective, Randomized, Open-Label, Multicenter Study.

BACKGROUND: Bone-graft substitutes are commonly used for the augmentation of traumatic bone defects in tibial plateau fractures. However, their clinical performance compared with that of autologous bone-grafting, the gold standard in bone defect reconstruction, still remains under debate. This study investigates the differences in quality of life, pain, and radiographic outcomes in the treatment of tibial plateau fracture-associated bone defects with either autologous bone grafts or a bioresorbable hydroxyapatite and calcium sulfate cement (CERAMENT BONE VOID FILLER [CBVF]; BONESUPPORT). METHODS: In this study, 135 patients with acute depression and split-depression fractures of the proximal part of the tibia (OTA/AO types 41-B2 and 41-B3) were enrolled in a prospective, controlled, randomized, multicenter trial including 20 hospitals in Germany. Patients were randomized to receive either autologous iliac bone graft or CBVF for reconstruction of the bone defect. The primary outcome measures were the Short Form (SF)-12 version 2 Physical Component Summary (PCS) score at week 26 (the study was designed to show noninferiority of the CBVF with regard to the PCS with a prespecified margin of -5 points) and the pain level at 26 weeks postoperatively measured by a visual analog scale (VAS). The secondary outcomes were the SF-12 version 2 Mental Component Summary (MCS) and SF-12 PCS scores at weeks 1, 6, and 12 and bone-healing on radiographs. RESULTS: Age, sex, fixation methods, and fracture pattern were comparable in both groups. There were no significant differences (p > 0.05) in the SF-12 PCS or VAS scores at postoperative week 26. There was a significant reduction of blood loss (p = 0.007) and pain levels (p = 0.008) at postoperative day 1 in the CBVF group. The rates of fracture-healing, defect remodeling, and articular subsidence were not significantly different (p > 0.05) in both groups. CONCLUSIONS: Bioresorbable CBVF was noninferior to autologous bone graft with regard to both patient-reported and radiographic outcomes in tibial plateau fractures of OTA/AO types 41-B2 and 41-B3. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Causes of Residual Back Pain at Early Stage After Percutaneous Vertebroplasty: A Retrospective Analysis of 1,316 Cases.

BACKGROUND: Percutaneous vertebroplasty (PVP) is now well accepted in the treatment of painful osteopathic vertebral compression fractures (OVCF), providing early pain relief and strengthening of the bone of the vertebrae. However, some patients still experienced severe back pain after PVP. OBJECTIVES: To analyze the possible reason for unsatisfactory back pain relief (UBPR) after PVP at early stage. STUDY DESIGN: Retrospective analysis. SETTING: Hong-Hui Hospital in Xi'an. METHODS: Between March 2013 and January 2015, a total of 1,316 patients with OVCF were treated by PVP at our Hospital. Demographics, clinical data, and surgical data were collected to analyze the factors associated with UBPR after PVP. RESULTS: Sixty cases complained of UBPR, and the prevalence was 4.6%. Univariate analyses showed that preoperative bone mineral density (BMD), number of fractures, cement distribution and volume injected per level, lumbodorsal fascia contusion, and depression were associated with UBPR after PVP (P < 0.001). Multivariate analysis revealed that preoperative BMD (odds ratio [OR], 3.577; P = 0.029), lumbodorsal fascia contusion (OR, 3.805; P = 0.002), number of fractures (OR, 3.440; P < 0.001), cement volume injected per level (OR, 0.079; P < 0.001), cement distribution (OR, 3.009; P = 0.013), and depression (OR, 3.426; P = 0.028) were independently associated with UBPR after PVP at the early postoperative stage. LIMITATIONS: A further prospective controlled study is needed to explore the association between the different degrees of the aforementioned factors and UBPR after PVP. CONCLUSIONS: Preoperative low BMD, lumbodorsal fascial injury, multiple segment PVP, insufficient cement injected volume, unsatisfactory cement distribution, and depression were strong risk factors associated with UBPR after PVP in patients with OVCF. KEY WORDS: Unsatisfactory back pain relief, residual back pain, percutaneous vertebroplasty.

Biomechanical evaluation of calcium phosphate-based nanocomposite versus polymethylmethacrylate cement for percutaneous kyphoplasty.

BACKGROUND CONTEXT: Polymethylmethacrylate (PMMA) is the most commonly used filling material when performing percutaneous kyphoplasty (PKP) for the treatment of osteoporotic vertebral compression fractures. However, there are some inherent and unavoidable drawbacks with the clinical use of PMMA. PMMA bone cement tends to leak during injection, which can lead to injury of the spinal nerves and spinal cord. Moreover, the mechanical strength of PMMA-augmented vertebral bodies is extraordinary and this high level of mechanical strength might predispose to adjacent vertebral fractures. A novel biodegradable calcium phosphate-based nanocomposite (CPN) for PKP augmentation has recently been developed to potentially avoid these issues. PURPOSE: By comparison with PMMA, the leakage characteristics, biomechanical properties, and dispersion of CPN were evaluated when used for PKP. STUDY DESIGN: Biomechanical evaluation and studies on the dispersion and anti-leakage properties of CPN and PMMA cements were performed and compared using cadaveric vertebral fracture model, sheep vertebral fracture model, and simulated rigid foam model. METHODS: Sheep vertebral bodies were decalcified by ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) to simulate osteoporosis in vitro. After compression to create wedge-shaped fractures using a self-designed fracture creation tool, human cadaveric vertebrae and decalcified sheep vertebrae were augmented by PKP. In addition, three L5 vertebral bodies from human cadavers were used in a contrast vertebroplasty (VP) augmentation experiment. Occurrence of cement leakage was observed and compared between CPN and PMMA during the process of vertebral augmentation. Open-cell rigid foam model (Sawbones#1522-507) was used to create a simulated leakage model for the evaluation of the leakage characteristics of CPN and PMMA with different viscosities. The augmentation effects of CPN and PMMA were evaluated in human cadaveric and decalcified sheep vertebral models and then compared to the results from solid rigid foam model (Sawbones#1522-23). The dispersion abilities of CPN and PMMA were evaluated via three methods as follows. The dispersion volume and dispersion ratio were calculated by three-dimensional reconstruction using human vertebral body CT scans; the ratio of cement area to injection volume was calculated from three-dimensional sections of micro-CT scans of a sheep vertebra; and the micro-CT images of cement dispersion in open-cell rigid foam model (Sawbones#1522-507) were compared between CPN and PMMA. This study was funded by the National Natural Science Foundation of China (No. 81622032, 190,000 dollars and No. 51672184, 90,600 dollars), Principal Project of Natural Science Research of Jiangsu Higher Education Institutions (No. 17KJA180011, 22,000 dollars), and Jiangsu Innovation and Entrepreneurship Program (146,000 dollars). RESULTS: There was no significant difference in vertebral height between CPN and PMMA during PKP augmentation and both cements restored the vertebral height after augmentation. In PKP augmentation experiment, posterior wall cement leakage occurred in 75% of human vertebrae augmented with PMMA; however, no leakage occurred in human vertebrae augmented with CPN. Anterior leakage occurred in all vertebrae augmented by PMMA, while in only 75% of vertebra augmented by CPN. Furthermore, CPN and PMMA had completely different leakage patterns in the simulated rigid foam model whether administered at the same injection speed or under the same injection force, suggesting that CPN has anti-leakage characteristics. The augmentation in human cadaveric vertebrae was lower with CPN compared to PMMA (1,668±816 N vs. 2,212±813 N, p=.459, respectively), but this difference was not significant. The augmentation force in sheep vertebral bodies reached 1,393±433 N when augmented with PMMA, but 1,108±284 N when augmented with CPN. The dispersion of CPN was better, and the dispersion volume and ratio were greater, with CPN than with PMMA. Imaging of the open-cell rigid foam model showed completely different dispersion modes for CPN and PMMA. After injection, the PMMA cement formed a contracted clump in the open-cell rigid foam model. However, the CPN cement extended many antennae outward, appearing to spread to the surrounding area. The surface areas of the CPN cement blocks with different liquid-to-solid ratios were significantly larger than the surface area of the PMMA cement in the open-cell rigid foam model (p<.05). CONCLUSIONS: CPN has anti-leakage properties, which might be related to its high viscosity and viscoplasticity. CPN had a slightly lower augmentation force than PMMA when used in cadaveric vertebrae, decalcified sheep vertebrae, and in the standard rigid foam model. However, CPN diffused more easily into cancellous bone than did PMMA and encapsulated bone tissue during the dispersion process. The excellent dispersion of CPN generated better interdigitation with cancellous bone, which may be why the augmentation effect of CPN is similar to that of PMMA. CLINICAL SIGNIFICANCE: Biodegradable CPN is a potential alternative to PMMA cement in PKP surgery, in which CPN is likely to reduce the cement leakage during the surgery and avoid the post-surgery complications caused by excessive strengths and nondegradability of PMMA cement.

Is bone-cement augmentation of screw-anchor fixation systems superior in unstable femoral neck fractures? A biomechanical cadaveric study.

OBJECTIVES: Improved fixation techniques with optional use of bone cements for implant augmentation have been developed to enhance stability and reduce complication rates after osteosynthesis of femoral neck fractures. This biomechanical study aimed to evaluate the effect of cement augmentation on implant anchorage and overall performance of screw-anchor fixation systems in unstable femoral neck fractures. METHODS: Ten pairs of human cadaveric femora were used to create standardized femoral neck fractures (Pauwels type 3 fractures; AO/OTA 31-B2) with comminution and were fixed by means of a rotationally stable screw-anchor (RoSA) system. The specimens were assigned pairwise to two groups and either augmented with PMMA-based cement (Group 1, augmented) or left without such augmentation (Group 2, control). Biomechanical testing, simulating physiological loading at four distinct load levels, was performed over 10.000 cycles for each level with the use of a multidimensional force-transducer system. Data was analysed by means of motion tracking. RESULTS: Stiffness, femoral head rotation, implant migration, femoral neck shortening, and failure load did not differ significantly between the two groups (p ≥ .10). For both groups, the main failure type was dislocation in the frontal plane with consecutive varus collapse). In the cement-augmented specimens, implant migration and femoral neck shortening were significantly dependent on bone mineral density (BMD), with higher values in osteoporotic bones. There was a correlation between failure load and BMD in cement-augmented specimens. CONCLUSION: In screw-anchor fixation of unstable femoral neck fractures, bone-cement augmentation seems to show no additional advantages in regard to stiffness, rotational stability, implant migration, resistance to fracture displacement, femoral neck shortening or failure load.

Analysis of the long-term efficacy of core decompression with synthetic calcium-sulfate bone grafting on non-traumatic osteonecrosis of the femoral head.

OBJECTIVE: to investigate the safety and long-term efficacy of core decompression with synthetic calcium-sulfate bone grafting on non-traumatic osteonecrosis of the femoral head. METHOD: a total of 76 patients with non-traumatic osteonecrosis of the femoral head were admitted to our hospital from February 2012 to November 2014 and included in the study. All the patients were treated by core decompression with synthetic calcium-sulfate bone grafting. After treatment, the patients were followed-up for 12 months. The operation time, intraoperative blood loss, and perioperative complications were also recorded intraoperatively to evaluate the clinical efficacy and safety. The preoperative and postoperative pain scores measured by visual analogy score (VAS) were also recorded and compared. RESULTS: all of the 76 patients were successfully operated and included in the study. The mean operation time was 34.6±14.2 min, and the intraoperative blood loss was 23.6±8.9 mL. The patients hip functions were assessed on the basis of the Harris hip score, 3 and 12 months after operation. The excellent rates 3 and 12 months after operation were significantly higher than those before operation (P<0.05). The imaging stabilities of the hip joints 3 and 12 months after operation were significantly higher than those before operation (P<0.05). The patient postoperative pain scores (VAS score) gradually decreased. The VAS scores 12 months after operation were significantly lower than those before operation (P<0.05). CONCLUSION: the long-term efficacy of core decompression with synthetic calcium-sulfate bone grafting on non-traumatic osteonecrosis of the femoral head is good and accompanied with significantly improved postoperative joint functions.

Calcium Phosphate Cement Paste Injection as a Fiducial Marker of Cervical Cancer.

BACKGROUND/AIM: Calcium phosphate cement (CPC) is used to fill bone voids in dental, orthopedic, and craniofacial applications. This study evaluated CPC marker as an injectable non-metallic fiducial marker. MATERIALS AND METHODS: Six patients received 3-5 injections of CPC paste placed at a depth of 10 mm into tumors of the cervix before treatment planning CT (TPCT). Patients were treated with external-beam radiotherapy (EBRT) and high-dose rate brachytherapy (BT). We investigated marker visibility on cone-beam CT (CBCT), T2-weighted MRI, and interfraction of the marker motion for cervical cancer patients. RESULTS: Of a total of 22 visible CPC markers at TPCT, 17 CPC markers were visible on the first CBCT. Excluding one patient, all markers were visible on CBCT during EBRT. Of 16 visible CPC markers on CBCT, 13 CPC markers were visible on the magnetic resonance imaging (MRI) obtained before BT. For CPC marker centroid movement, the mean-of-means/systematic variation/random variation were 0.2/0.4/1.4, -1.6/5.1/4.1, and -3.4/2.1/2.8 mm for the left-right, dorsal-ventral, and cranial-caudal directions, respectively. CONCLUSION: This is the first report of a CPC marker injected into tumors of the cervix. It can be visualized on CBCT and MRI with reductions in marker loss and artifacts.

Is vertebral body stenting in combination with CaP cement superior to kyphoplasty?

PURPOSE: In the evolution of the minimally invasive treatment of vertebral compression fractures, vertebral body stenting (VBS) was developed to reduce intraoperative and secondary loss of vertebral height. Particularly in combination with the usage of biodegradable cement, the influence of VBS on the rate of intraoperative complications and long-term outcome is unclear. The purpose of this study was to investigate the differences between balloon kyphoplasty (BKP) and VBS regarding their long-term clinical and radiological outcome in combination with calcium phosphate (CaP) application instead of polymethyl methacrylate (PMMA). METHODS: This retrospective study included 49 patients with fresh mono-segmental thoracolumbar fractures without neurological signs treated with VBS or BKP and CaP cement (Calcibone). The outcome was evaluated with the visual analogue pain scale (VAS), the Oswestry disability score (ODI), and radiologically assessed. RESULTS: In the course of the radiological follow-up, the VBS group showed statistically significant less vertebral height loss than the BKP group. However, with respect to VAS and ODI scores there were no statistically significant differences between the VBS and BKP group in the clinical follow-up. The rate of cement leakage was comparable in both groups. CONCLUSIONS: Both techniques facilitated good clinical results in combination with absorbable cement augmentation. In particular, the VBS enabled us to benefit from the advantages of the resorbable isothermic CaP cement with an improved radiological outcome in the long term compared to BKP. However, there was a mentionable loss of reduction in the follow-up in both groups compared to previously published data with PMMA cement. These slides can be retrieved under Electronic Supplementary Material.

Time to augment?! Impact of cement augmentation on pedicle screw fixation strength depending on bone mineral density.

PURPOSE: Cement augmentation of pedicle screws is known to increase their mechanical strength. Aim was to evaluate the impact of cement augmentation on pedicle screw fatigue strength in dependence of the bone mineral density (BMD). METHODS: Twenty-one human L2 vertebral bodies from donors between 19 and 96 years of age were used for in vitro experiments. BMD was measured using quantitative computed tomography (QCT). Two pedicle screws were inserted in each specimen and unilaterally augmented with bone cement. Fatigue testing was performed using a cranio-caudal sinusoidal, cyclic load (0.5 Hz) with increasing compression force (100 N + 0.1 N/cycles). Results were evaluated for the BMD groups: normal: BMD > 120 mg/cm3, osteopenic: BMD 80-120 mg/cm3, and osteoporotic: BMD < 80 mg/cm3 bone mass. RESULTS: There was a significant correlation between fatigue force and BMD for the non-augmented and augmented screws (non-augmented R2 = 0.839, p < 0.001; augmented R2 = 0.551, p < 0.001). There was a significantly increased fatigue strength of the augmented screws over the non-augmented screws in the osteoporotic group (p = 0.001), while the differences in the other groups were not significant (normal p = 0.818/osteopenic p = 0.132). CONCLUSIONS: The benefit of pedicle screw cement augmentation significantly depends on the bone mineral density and has the greatest extent of increased fatigue strength in osteoporotic vertebrae. Preoperative measurement of the BMD is strongly recommended to predict the benefit of augmentation and reinforce the decision for cement augmentation. These slides can be retrieved under Electronic Supplementary Material.

Calcium Phosphate Cement in the Surgical Management of Benign Bone Tumors.

BACKGROUND/AIM: This study assessed the mid- to long-term outcomes of calcium phosphate cement (CPC) implantation in benign bone tumor surgery. PATIENTS AND METHODS: Between 2000 and 2015, 130 patients underwent CPC implantation in benign bone tumor surgery. Radiographic findings and clinical outcomes were retrospectively evaluated. RESULTS: The mean follow-up period was 52 months. CPC filling immediately after surgery was sufficient, regardless of the amount of CPC used and the usage of adjuvant substances, which resulted in 92% of the patients' radiological results being classified as good or excellent. Significantly more patients had better CPC filling among patients with less hemorrhage and patients with tourniquet. The number of patients with good or excellent CPC filling had significantly increased by the final follow-up. CONCLUSION: CPC is a useful bone substitute for benign bone tumor surgery providing excellent osteoconductivity and long-lasting stability without internal fixation.

Improvement of physical properties of calcium phosphate cement by elastin-like polypeptide supplementation.

Calcium phosphate cements (CPCs) are synthetic bioactive cements widely used as hard tissue substitutes. Critical limitations of use include their poor mechanical properties and poor anti-washout behaviour. To address those limitations, we combined CPC with genetically engineered elastin-like polypeptides (ELPs). We investigated the effect of the ELPs on the physical properties and biocompatibility of CPC by testing ELP/CPC composites with various liquid/powder ratios. Our results show that the addition of ELPs improved the mechanical properties of the CPC, including the microhardness, compressive strength, and washout resistance. The biocompatibility of ELP/CPC composites was also comparable to that of the CPC alone. However, supplementing CPC with ELPs functionalized with octaglutamate as a hydroxyapatite binding peptide increased the setting time of the cement. With further design and modification of our biomolecules and composites, our research will lead to products with diverse applications in biology and medicine.

Feasibility of percutaneous cryoablation of vertebral metastases under local anaesthesia in ASAIII patients.

PURPOSE: spine metastases are common concern from several primary neoplasms, modern management include percutaneous techniques such as ablation and cementoplasty. This research aims to evaluate the treatment under local anaesthesia in high-risk patients (ASA III). METHODS AND MATERIAL: from January 2013 up to September 2016 we treated via percutaneous cryoablation 11 advanced oncological patients classified as ASA III, then retrospectively a review of their clinical history has been performed. Interventions were managed under local anaesthesia, injecting low doses of bupivacaine 2,5mg/ml (from10 to 30ml). Cryoprobes of 17G were introduced under CT guidance. VAS scores were evaluated pre, intra and post operative up to the 3rd month and further, statistical analyses were obtained using T student test. RESULTS: thirteen spinal metastases were cryoablated in 11 patients (6W, 5M; mean age of 53 years, range 52-81). Tumour location was: sacrum (n=6), lumbar spine (n=3), thoracic spine (n=2). The average VAS value during the procedure was 5,27 (standard deviation 0,90). There were statistically significant decreases in the median numeric VAS scale score at 1-week, 1-month, and 3-month time points (P<.001 for all). Technical success was achieved in all cases. Among patients with neurological deficit, some clinical improvement was assessed. CONCLUSION: cryoablation with or without subsequent cement injection can be safely performed with local anaesthesia for pain relief also in patients with high ASA score with higher risk of complications, in the absence of any other suitable treatment.

Preparation and in vivo evaluation of a silicate-based composite bone cement.

Silicate-based cements have been developed as a class of bioactive and biodegradable bone cements owing to their good in vitro bioactivity and ability to dissolve in a simulated body fluid. Until recently, however, the in vivo evidence of their ability to support bone regeneration is still scarce. In the present study, a pilot in vivo evaluation of a silicate-based composite bone cement (CSC) was carried out in a rabbit femur defect model. The cement was composed of tricalcium silicate, 45S5 bioglass and calcium sulfate, and the self-setting properties of the material were established. The in vivo bone integration and biodegradability of CSC were investigated and compared with those of bioactive glass particulates, and a calcium phosphate cement. The results showed that CSC underwent a relatively slower in vivo degradation as compared with bioactive glass and calcium phosphate cement. Histological observation demonstrated that bone contact area at the interface between the surrounding bone and CSC gradually increased with time proceeding. CSC kept its structural integrity during implantation in vivo because of its acceptable mechanical strength. These results provide evidence of effectiveness in vivo and suggest potential clinical applications of the silicate-based composite bone cements.

Percutaneous vertebroplasty under local anaesthesia: feasibility regarding patients' experience.

OBJECTIVE: Evaluate patients' intraoperative experience of percutaneous vertebroplasty (PV) performed without general anaesthesia in order to assess the feasibility of local anaesthesia and simple analgesic medication as pain control protocol. METHODS: Ninety-five patients who underwent single-site PV were consecutively included in the study between 2011 and 2013. Each procedure was achieved under local anaesthesia and perfusion of paracetamol, tramadol and dolasetron, with combined CT and fluoroscopy guidance. Numeric pain scale (NPS) was collected before, during and after intervention. After intervention, patients were asked to evaluate their experience as "very bad", "bad", "fair", "good" or "very good", independently of the pain. RESULTS: Indications for vertebroplasty were osteopenic fractures (78 %), aggressive angiomas (13 %) and somatic tumours (9 %). In 76 % of cases, patients' experience was described as "very good" (44 %) or "good" (32 %), whereas 19 % described it as "fair" and 5 % as "very bad". Mean operative NPS was 5.5. After intervention, NPS was significantly lower with a decrease of 4.5 points. No differences were found according to the localization, type of lesion, age or sex either in terms of experience or NPS. CONCLUSION: Percutaneous vertebroplasty is feasible under local anaesthesia alone, with a very good or good experience in 76 % of the patients. KEY POINTS: • Vertebroplasty is a first-line therapy for consolidation and pain control of vertebral lesions. • This procedure is commonly performed under general anaesthesia or conscious sedation. • We perform vertebroplasty under local anaesthesia and simple analgesic protocol with acceptable experience. • Percutaneous vertebroplasty can safely be proposed in a fragile population.