Vertebral Reinforcement Research Articles

Spatiotemporal Regulation of Injectable Heterogeneous Silk Gel Scaffolds for Accelerating Guided Vertebral Repair.

Osteoporotic vertebral fracture is jeopardizing the health of the aged population around the world, while the hypoxia microenvironment and oxidative damage of bone defect make it difficult to perform effective tissue regeneration. The balance of oxidative stress and the coupling of vessel and bone ingrowth are critical for bone regeneration. In this study, an injectable heterogeneous silk gel scaffold which can spatiotemporally and sustainedly release bone mesenchymal stem cell-derived small extracellular vesicles, HIF-1α pathway activator, and inhibitor is developed for bone repair and vertebral reinforcement. The initial enhancement of HIF-1α upregulates the expression of VEGF to promote angiogenesis, and the balance of reactive oxygen species level is regulated to effectively eliminate oxidative damage and abnormal microenvironment. The subsequent inhibition of HIF-1α avoids the overexpression of VEGF and vascular overgrowth. Meanwhile, complex macroporous structures and suitable mechanical support can be obtained within the silk gel scaffolds, which will promote in situ bone regeneration. These findings provide a new clinical translation strategy for osteoporotic vertebral augmentation on basis of hypoxia microenvironment improvement.

Management of Spinal Bone Metastases With Radiofrequency Ablation, Vertebral Reinforcement and Transpedicular Fixation: A Retrospective Single-Center Case Series.

Spine is a frequent site of bone metastases, with a 8.5 months median survival time after diagnosis. In most cases treatment is only palliative. Several advanced techniques can ensure a better Quality of Life (QoL) and increase life expectancy. Radiofrequency ablation (RFA) uses alternating current to produce local heating and necrosis of the spinal lesion, preserving the healthy bone. RFA is supported by vertebral reinforcement through kyphoplasty and vertebroplasty in order to stabilize the fracture with polymethylmethacrylate (PMMA) injection, restoring vertebral body height and reducing the weakness of healthy bone. The aim of this study is to demonstrate the efficacy and advantages of RFA plus vertebral reinforcement through PMMA vertebroplasty and fixation in patients affected by bone spinal metastases. We retrospectively analyzed 54 patients with thoraco-lumbar metastatic vertebral fractures admitted to our Unit between January 2014 and June 2020. Each patient underwent RFA followed by PMMA vertebroplasty and transpedicle fixation. We evaluated pain relief through the Visual Analogue Scale (VAS) Score and PMMA vertebral filling based on the mean Saliou filling score. Analysis of variance (ANOVA) was used to test pain relief with statistical significance for p<0.05. A total of 54 patients (median age 63,44 years; range 34-86 years), with a total of 63 infiltrated vertebrae, were treated with RFA, PMMA vertebroplasty and transpedicular screw fixation; average operative time was 60.4 min (range 51–72). The preoperative average VAS score decreased significantly from 7.81 to 2.50 (p < 0.05) after 12 months. Based on Saliou filling score, filling was satisfactory (12–18) in 20 vertebrae (31,7%), mediocre (6–11) in 33 vertebrae (52,4%), inadequate (0–5) in 10 vertebrae (15,9%). A consistent PMMA filling of vertebral bodies was successfully achieved with significant pain relief. Concomitant RFA, PMMA vertebroplasty and pedicle screw fixation represent a safe and effective technique for the management of spinal metastases, improving clinical outcome and pain control.

Management of spinal bone metastases with radiofrequency ablation, vertebral reinforcement and transpedicular fixation: a retrospective single-center case series

Management of spinal bone metastases with radiofrequency ablation, vertebral reinforcement and transpedicular fixation: a retrospective single-center case series

Management of spinal bone metastases with radiofrequency ablation, vertebral reinforcement and transpedicular fixation: A retrospective single-center case series

Management of spinal bone metastases with radiofrequency ablation, vertebral reinforcement and transpedicular fixation: A retrospective single-center case series

Prophylactic vertebroplasty procedure applied with a resorbable bone cement can decrease the fracture risk of sandwich vertebrae: long-term evaluation of clinical outcomes.

A sandwich vertebra is formed after multiple osteoporotic vertebral fractures treated by percutaneous vertebroplasty, which has a risk of developing new fractures. The purpose of our study was to (i) investigate the occurrence of new fractures in sandwich vertebra after cement augmentation procedures and to (ii) evaluate the clinical outcomes after prophylactic vertebral reinforcement applied with resorbable bone cement.From June 2011 to 2014, we analysed 55 patients with at least one sandwich vertebrae and treated with percutaneous vertebroplasty. Eighteen patients were treated by prophylactic vertebroplasty with a resorbable bone cement to strengthen the sandwich vertebrae as the prevention group. The others were the non-prevention group. All patients were examined by spinal radiographs within 1 day, 6 months, 12 months, 24 months and thereafter.The incidence of sandwich vertebra is 8.25% (55/667) in our study. Most sandwich vertebrae (69.01%, 49/71) are distributed in the thoracic–lumbar junction. There are 24 sandwich vertebrae (18 patients) and 47 sandwich vertebrae (37 patients) in either prevention group or non-prevention group, respectively. No significant difference is found between age, sex, body mass index, bone mineral density, cement disk leakage, sandwich vertebrae distribution or Cobb angle in the two groups. In the follow-up, 8 out of 37 (21.6%) patients (with eight sandwich vertebrae) developed new fractures in non-prevention’ group, whereas no new fractures were detected in the prevention group. Neither Cobb angle nor vertebral compression rate showed significant change in the prevention group during the follow-up. However, in the non-prevention group, we found that Cobb angle increased and vertebral height lost significantly (P < 0.05).Prophylactic vertebroplasty procedure applied with resorbable bone cement could decrease the rate of new fractures of sandwich vertebrae.

Anestesia subaracnoidea hipobárica metamérica para las técnicas de refuerzo vertebral. Experiencia en 6 casos

Vertebral reinforcement techniques, such as percutaneous vertebroplasty and kyphoplasty, are minimally invasive procedures used in the treatment of fractured or collapsed vertebras. The anaesthetic techniques employed during these procedures are diverse and with variable results. We report 6 cases, vertebroplasty and kyphoplasty using subarachnoid metameric anaesthesia with a hypobaric technique. Haemodynamic stability and analgesia were satisfactory in all of them.

Cement embolism during a kyphoplasty

Figure 1: Postoperative lateral chest X-ray showing the excellent alignment following short fixation, a chest tube to drain a pleural effusion, the cement leakage (arrow) and the vertebral reinforcement material (asterisk). The mechanism of the embolism was probably a vascular entry of cement during high pressure inflation to get the compressed vertebral separated. Figure 2: CT image: we can observe a right pleural effusion with a filiform foreign body into the azygos vein, pulmonary artery and its segmentary branch. The vascular course of the embolized material was azygos vein, superior vena cava, right atrium, right ventricle and right pulmonary artery.

Biomechanical, histological and histomorphometric analyses of calcium phosphate cement compared to PMMA for vertebral augmentation in a validated animal model

Calcium phosphate cements (biocements) are alternative materials for use in vertebral augmentation procedures, and are a potential solution to problems associated with polymethylmethacrylate (PMMA) cements. The aim of this study is to demonstrate the utility of percutaneously injected biocements compared with PMMA in a validated animal model of osteoporosis. Fortyseven augmentation procedures were performed on 11 osteoporotic sheep. 9 vertebrae were augmented with PMMA and 38 with a biocement. The animals were killed in four groups: at 7 days, 3 months, 6 months, and 1 year after intervention. Radiological study and TC of the pieces were obtained to evaluate for leakage, cement diffusion, and integration. In total, 26 biomechanic studies and 27 histomorphometry analyses were performed, included control vertebrae. In 20.9% of the vertebrae, the hole was empty at sacrifice. The pattern of fracture was heterogeneous, and cement augmentation did not increase vertebral strength or decrease vertebral stiffness compared to control vertebrae, with neither PMMA or biocement. The rate of remodeling of the biocement was not predictable. In the single majority, there is peripheral remodeling, staying the volume of injected biocement stable. Even though this animal model may not be useful to analyze the biomechanical pattern of treated vertebrae, it demonstrates that the percutaneous use of biocements in vertebral augmentation techniques is not predictable. This is one reason not to recommend its use presently as a substitute for PMMA in vertebral reinforcement procedures.

A Biomechanical Investigation of Vertebroplasty in Osteoporotic Compression Fractures and in Prophylactic Vertebral Reinforcement

Cadaveric single vertebrae were used to evaluate vertebroplasty as a prophylactic treatment and as an intervention for vertebral compression fractures. To investigate the biomechanical characteristics of prophylactic reinforcement and postfracture augmentation of cadaveric vertebrae. Percutaneous vertebroplasty is a treatment option for osteoporotic vertebral compression fractures. Short-term results are promising, but longer-term studies have suggested a possible accelerated failure rate in the adjacent vertebral body. Limited research has been conducted into the effects of prophylactic vertebroplasty in osteoporotic vertebrae. This study aims to elucidate the biomechanical differences between the 2 treatment groups. Human vertebrae were assigned to 2 scenarios: Scenario 1 simulated a wedge fracture followed by cement augmentation; Scenario 2 involved prophylactic augmentation using vertebroplasty. Micro-CT imaging was performed to assess the bone mineral density, vertebral dimensions, fracture pattern, and cement volume. All augmented specimens were then compressed under an eccentric flexion load to failure. Product of bone mineral density and endplate surface area gave a good prediction of failure strength when compared with actual failure strength of specimens in Scenario 1. Augmented vertebral bodies showed an average cement fill of 23.9% +/- 8.07%. There was a significant postvertebroplasty increase in failure strength by a factor of 1.72 and 1.38 in Scenarios 1 and 2, respectively. There was a significant reduction in stiffness following augmentation for Scenario 1 (t = 3.5, P = 0.005). Stiffness of the vertebral body in Scenario 2 was significantly greater than observed in Scenario 1 (t = 4.4, P = 0.0002). Results suggest that augmentation of the vertebrae postfracture significantly increases failure load, while stiffness is not restored. Prophylactic augmentation was seen to increase failure strength in comparison to the predicted failure load. Stiffness appears to be maintained suggesting that prophylactic vertebroplasty maintains stiffness better than vertebroplasty postfracture.

Évaluation biomécanique d’une instrumentation rachidienne postérieure dans une fracture lombaire de type « burst »: Comparaison de deux montages

Purpose of the study Burst fractures generally occur due to trauma to the thoracolumbar spine. Surgery is indicated for unstable fractures. Posterior instrumentation with pedicular screws is generally proposed. In certain circumstances, hooks may be preferred due to excessive risk of insertion of the pedicular screw. The purpose of this study was to compare two posterior instrumentations, one using pedicular screws on either side of the fracture each protected by hoods and a second composed of the same pedicular screws inserted under the fracture hooks above. Material and methods Twelve spinal specimens from human cadavers composed of segments T10 to L2 were used. Range of flexion, extension, lateral inclination, and rotation were noted on T10 up to application of 7 Nm. Spinal segments were tested first intact, then in four configurations: 1) instrumented without lesion, 2) lesion simulating burst fracture of L1 without section of the interspinous ligament, 3) and with section of the interspinous ligament, and 4) with L1 corporectomy. Finally a test to rupture was performed by applying a flexion moment up to fracture. Results Mean flexion-extension of the instrumented spine was limited compared with the intact spine for both instrumentation configurations and irrespective of the lesion. The same behavior was observed for lateral inclination with less pronounced motion with the first instrumentation. For rotation, the range of motion increased clearly with the second instrumentation and this with the first lesion while with the first instrumentation, rotation amplitude remained below that of the intact spine. There was however an increase in the vertical displacement during flexion-extension for both instrumentations. For the rupture test, the mean flexion moment at rupture was 14.4 Nm (10.6-22 Nm) with no difference between the two instrumentations. Discussion This mode simulating burst fractures of the spine appears to be reproducible and more realistic than corporectomy. Attention should be taken concerning the limits of this type of study since fractures can occur for forces as small as 10.6 Nm. Thus we observed that pedicle screw configurations and also fractures produced mean ranges of motion greater than intact segments irrespective of the type of lesion simulated. However, the net increase in motion was observed during rotation movements when hooks were used, even when they were placed only below the fracture. Putting pressure on the hooks does not prevent them from slipping along the lamina. But neither of these two configurations controls the fracture gap. A vertebral reinforcement might be necessary.

Biomechanics of prophylactic vertebral reinforcement.

The effects of bone cement placement, volume, and bone density on the degree of biomechanical reinforcement on cadaveric vertebral bodies were studied using experimentally calibrated detailed finite element models. To investigate the efficacy of prophylactic vertebroplasty on intact vertebral bodies with respect to biomechanical recovery and fracture risk reduction. Vertebroplasty is a potentially effective fracture prevention treatment, but the risk of complications due to cement leakage must be minimized. Therefore, the least amount of bone cement required to improve vertebral strengths to low fracture risk levels need to be determined. Six different polymethyl methacrylate volumes--1, 2.5, 3.5, 5, 7.5 and 9 cm--were virtually implanted into previously validated vertebral body finite element models, following bipedicular and posterolateral vertebroplasty approaches. Stiffness and fracture load of the treated and untreated vertebral body models under uniaxial compression were determined. Greater augmentation effects were observed for vertebral bodies with average quantitative computed tomography densities below 0.1 g/cm injected with polymethyl methacrylate volumes higher than 20% compared to lower injection volumes and higher bone densities, as well as for the bipedicular approach versus posterolateral. Vertebral bodies at high risk of fracture required at least 20% fill of polymethyl methacrylate to improve the mechanical integrity of vertebral bodies to low fracture risk levels, whereas 5% to 15% polymethyl methacrylate volumes were needed for the medium-risk vertebral bodies. Prophylactic vertebroplasty can be effective in reducing fracture risk. However, for the polymethyl methacrylate volume (20%) required for the successful reinforcement of high-risk vertebral bodies, the risk of complications will be as high as that for current vertebroplasty procedure for fracture repair. Therefore, alternative materials have to be investigated for prophylactic vertebroplasty. Furthermore, bipedicular vertebroplasty is the recommended approach due to its higher strengthening effect and easier surgical access than the posterolateral case.