mL Of Cement Research Articles

Percutaneous Kyphoplasty via Transverse Process-Rib-Pedicle Approach for Upper and Middle Thoracic Osteoporosis Fracture with Pedicle Stenosis

ObjectiveTo explore the clinical effect of percutaneous kyphoplasty via Process-Rib-Pedicle approach for upper and middle thoracic osteoporosis fracture with Pedicle Stenosis. MethodsThis study is a retrospective observational study. In this study, we retrospectively analyzed the data of 62 patients with upper thoracic vertebral bone loss compression fracture (OVCF) treated via the Process-Rib-Pedicle pathway PKP at the First Affiliated Hospital of Soochow University from January 2020 to December 2022. The patients were divided into group A(Unilateral PKP, 38 cases) and group B(Bilateral PKP, 24 cases) . The aspects of surgical safety, clinical efficacy and radio-logical outcome were investigated. ResultsAll 62 patients successfully completed the surgery without any spinal cord, nerve, or vascular injury, and there were no complications such as infection and vascular embolism. The differences in VAS scores（P<0.05）, ODI functional index（P<0.05）, and Cobb angle（P<0.05） were significant when comparing preoperative and postoperative periods, and the differences were not significant when comparing the postoperative periods (P>0.05); There were no statistically significant differences in days of hospital stay(P=0.653), and the rate of bone cement leakage (P=0.537 )between the two groups. ConclusionFor upper middle osteoporotic thoracic vertebral fractures with pedicle stenosis, puncture via the Process-Rib-Pedicle path is a safe and reliable puncture route, and more than 2.5 ml of cement can achieve good clinical outcomes, regardless of bilateral or unilateral PKP.

Analysis of injected cement volume and clinical outcomes following balloon-assisted kyphoplasty in a series of 368 patients

ObjectiveBalloon-assisted kyphoplasty (BAK) is a modified vertebroplasty technique developed to treat vertebral compression fractures (VCFs) secondary to osteoporosis. This study investigates the association between injected cement volume and the development of subsequent VCFs after BAK. MethodsA retrospective analysis of 368 patients who underwent BAK at a single institution was performed from 2001 to 2021. Inclusion was defined by at least 2 years of follow-up. Clinical characteristics and outcomes following BAK, including subsequent fractures at adjacent and remote levels, were identified. Patients that underwent a thoracic BAK were stratified by injected cement volume: below or equal to the median (≤ 6.0 mL, 265 vertebrae) or above the median (> 6.0 mL, 144 vertebrae). Patients that underwent a lumbar BAK were similarly stratified: below or equal to the median (≤ 8.0 mL, 233 vertebrae) or above the median (>8.0 mL, 160 vertebrae). ResultsA total of 802 vertebrae were treated. The average volume of cement was recorded in the thoracic (6.2 ± 1.9 mL) and lumbar (7.8 ± 1.8 mL) vertebrae. In the thoracic spine, vertebrae that were injected with > 6.0 mL of cement underwent a greater change in local kyphotic angle (P = 0.0001) and were more likely to develop adjacent-level VCFs (P = 0.032) after kyphoplasty. Univariate analysis did not elucidate any additional risk factors. There were no statistical differences in clinical outcomes between the three groups of lumbar vertebrae. ConclusionsLarger volumes of injected cement were associated with a greater change in local kyphosis and subsequent adjacent-level fractures after BAK in the thoracic spine. This association was not found in the lumbar spine. Close attention to injected cement volumes must be made in the thoracic spine and patients who undergo significant kyphotic correction should be carefully observed postoperatively.

Static study and numerical simulation of the influence of cement distribution in the upper and lower adjacent vertebrae on sandwich vertebrae in osteoporotic patients: Finite element analysis.

We analyzed the influence of the location of the upper and lower cement on the sandwich vertebrae (SV) by computer finite element analysis. A finite element model of the spinal segment of T11-L1 was constructed and 6 mL of cement was built into T11 and L1 simultaneously. According to the various distributions of bone cement at T11 and L1, the following four groups were formed: (i) Group B-B: bilateral bone cement reinforcement in both T11 and L1 vertebral bodies; (ii) Group L-B: left unilateral reinforcement in T11 and bilateral reinforcement in L1; (iii) Group L-R: unilateral cement reinforcement in both T11 and L1 (cross); (iv) Group L-L: unilateral cement reinforcement in both T11 and L1 (ipsilateral side). The maximum von Mises stress (VMS) and maximum displacement of the SV and intervertebral discs were compared and analyzed. The maximum VMS of T12 was in the order of size: group B-B < L-B < L-R < L-L. Group B-B showed the lowest maximum VMS values for T12: 19.13, 18.86, 25.17, 25.01, 19.24, and 20.08 MPa in six directions of load flexion, extension, left and right lateral bending, and left and right rotation, respectively, while group L-L was the largest VMS in each group, with the maximum VMS in six directions of 21.55, 21.54, 30.17, 28.33, 19.88, and 25.27 MPa, respectively. Compared with the uneven distribution of bone cement in the upper and lower adjacent vertebrae (ULAV), the uniform distribution of bone cement in the ULAV reduced and uniformed the stress load on the SV and intervertebral disc. Theoretically, it can lead to the lowest incidence of sandwich vertebral fracture and the slowest rate of intervertebral disc degeneration.

Which head element is more effective for cement augmentation of TFNA? Helical blade versus lag screw

BackgroundEarly fixation and rehabilitation is the gold standard treatment for intertrochanteric femur fractures. Cement augmentation through perforated head elements has been developed to avoid postoperative complications such as cut-out or cut-through. The purpose of this study was to compare two head elements in terms of cement distribution using computed tomography (CT) and to examine their initial fixation and clinical outcomes.MethodsElderly patients who had intertrochanteric fractures were treated with a trochanteric fixation nail advanced (TFNA) helical blade (Blade group) or a TFNA lag screw (Screw group). In both groups, 4.2 mL of cement was injected under an image intensifier (1.8 mL of cement was directed cranially and 0.8 mL each caudally, anteriorly, and posteriorly). Patient demographics and clinical outcome were investigated post-operatively. Cement distribution from the center of the head element was evaluated with CT. Maximum penetration depth (MPD) were measured in the coronal and sagittal planes. On each axial plane, the cross-sectional areas in the cranial, caudal, anterior and posterior directions were calculated. The sum of cross-sectional areas (successive 36 slices) was defined as the volume of the head element.ResultsThe Blade group included 14 patients, and the Screw group included 15 patients. In the Blade group, MPD in the anterior and caudal direction was significantly greater than that in the posterior direction (p < 0.01). In the Screw group, volume in the cranial and posterior direction was significantly greater than that in the Blade group (p = 0.03). Subsequently, the total volume in the Screw group was significantly larger than that in the Blade group (p < 0.01). No significant correlation was detected between bone mineral density, T score, young adult mean, and total cement volume. Change in radiographic parameters and clinical outcome such as Parker score and visual analog scale were similar in both groups. No patients suffered from cut-out / cut through or non-union.ConclusionsThe position of cement distribution through the lag screw is different from that through the helical blade, and the total volume of the head element is significantly larger in the lag screw. Both groups had similarly effective results in terms of mechanical stability after surgery, postoperative pain and early phase of rehabilitation.Trial registrationCurrent Controlled Trials ISRCTN45341843, 24/12/2022, Retrospectively registered.

Cement distribution and initial fixability of trochanteric fixation nail advanced (TFNA) helical blades

IntroductionEarly fixation and rehabilitation is the gold standard treatment for intertrochanteric femur fractures. To avoid postoperative complications such as cut-out or cut-through, cement augmentation with perforated helical blades has been developed. The purpose of this study was to evaluate the distribution of injected cement at the head–neck portion of proximal femur using computed tomography (CT) and to examine its initial fixability and clinical outcomes. Patients and methodsElderly patients who had intertrochanteric fractures were treated with a helical blade only (BO group) or with a helical blade and cement augmentation (CA group). After fracture reduction, trochanteric fixation nail advanced (TFNA) helical blades were inserted, aiming at the center/center position with 20 mm of tip-apex distance. In the CA group, 4.2 mL of cement was injected under an image intensifier (1.8 mL of cement was directed cranially and 0.8 mL each was directed to the caudally, anteriorly, and posteriorly). Patient demographics, radiographic parameters with CT, and post-operative clinical outcome were examined. ResultsEach group included nine patients with similar demographics. Maximum penetration depth (MPD) in the CA group was significantly greater than those in the BO group for all four directions (p < 0.01). In the CA group, the anterior MPD was significantly greater than the posterior (p < 0.01) and the cranial (p = 0.02) MPD. Surface area and volume in the CA group were two-times and three-times larger than that in the BO group, respectively. Among radiographic parameters, ΔRotation angle in the CA group was significantly smaller than that of the BO group (p = 0.03). For the ΔParker score, the CA group showed less of a decrease than in the BO group (p < 0.01). Visual analog scale (VAS) for the passive range of motion (ROM) and for full-load walking in the CA group was significantly lower than those in the BO group (p < 0.01). ConclusionsThe initial fixability of the TFNA helical blade with cement augmentation demonstrated double the surface area and triple the volume. This suppressed implant micro-motion, reduced postoperative pain, and accelerated rehabilitation in the acute phase.

Selections of Bone Cement Viscosity and Volume in Percutaneous Vertebroplasty: A Retrospective Cohort Study

We sought to evaluate the efficacy and complications of percutaneous vertebroplasty with different viscosities and volumes of bone cement in treating osteoporotic vertebral compression fractures (OVCFs). We conducted a retrospective cohort study of 307 patients treated for a single thoracolumbar level (T12-L2) OVCF in our hospital between January 2014 and December 2019. The patients were divided into 6 groups according to different viscosities (I: low-viscosity bone cement, II: high-viscosity bone cement) and injection volumes (A, 2-4 mL; B, 4-6 mL; C, 6-8 mL) of bone cement. Clinical and radiologic characteristics including visual analog scale, local kyphotic angle, anterior vertebral height ratio, cement leakage, and vertebral body recollapse rate were collected preoperatively, 2 days postoperation, and at the last follow-up to assess the efficacy and complications of each group. Regarding efficacy, there was no significant difference between the 2 kinds of bone cement. Injecting >4 mL of cement can provide patients with good improvements of clinical indicators and a low vertebral body recollapse rate. Injecting 6-8 mL of bone cement slightly improved the radiologic indicators. However, the leakage rate of low-viscosity bone cement increased significantly when the volume exceeded 6 mL. The leakage rate of high-viscosity bone cement did not increase significantly at the volume of 6-8 mL. In summary, when treating single thoracolumbar level OVCFs, the recommended volume of low-viscosity bone cement is 4-6 mL while the optimal volume of high-viscosity bone cement is 6-8 mL.

Cement augmentation of odontoid peg fractures: the effect of cement volume and distribution on construct stiffness.

The cement augmentation of a conventional anterior screw fixation in type II odontoid process fractures for elderly patients significantly increased stiffness and load to failure under anterior-posterior load in comparison with non-augmented fixation. The amount and quality of bone cement are usually taken ad hoc in clinical practise. In this study, we wanted to clarify the role of bone cement amount and its quality to the stiffness of odontoid and vertebrae body junction. Finite-element method was used to achieve different scenarios of cement augmentation. For all models, an initial stiffness was calculated. Model (1) the intact vertebrae were virtually potted into a polymethylmethacrylate base via the posterior vertebral arches. A V-shaped punch was used for loading the odontoid in an anterior-posterior direction. (2) The odontoid fracture type IIa (Anderson-D'Alonzo classification) was achieved by virtual transverse osteotomy. Anterior screw fixation was virtually performed by putting self-drilling titanium alloy 3.5mm diameter anterior cannulated lag screw with a 12mm thread into the inspected vertebrae. A V-shaped punch was used for loading the odontoid in an anterior-posterior direction. The vertebrae body was assumed to be non-cemented and cemented with different volume. The mean cement volume was lowest for body base filling with 0.47 ± 0.03ml. The standard body filling corresponds to 0.95 ± 0.15ml. The largest volume corresponds to 1.62 ± 0.12ml in the presence of cement leakage. The initial stiffness of the intact C2 vertebrae was taken as the reference value. The mean initial stiffness for non-porous cement (E = 3000MPa) increased linearly (R2 = 0.98). The lowest stiffness (123.3 ± 5.8N/mm) was measured in the intact C2 vertebrae. However, the highest stiffness (165.2 ± 5.2N/mm) was measured when cement leakage out of the odontoid peg occurred. The mean initial stiffness of the base-only cemented group was 147.2 ± 8.4N/mm compared with 157.9 ± 6.6N/mm for the base and body cemented group. This difference was statistically significant (p < 0.0061). The mean initial stiffness for porous cement (E = 500MPa) remains constant. Therefore, there is no difference between cemented and non-cemented junction. This difference was not statistically significant (p < 0.18). The present study showed that the low porous cement was able to significantly influence the stiffness of the augmented odontoid screw fixation in vitro, although further in vivo clinical studies should be undertaken. Our results suggest that only a small amount of non-porous cement is needed to restore stiffness at least to its pre-fracture level and this can be achieved with the injection of 0.7-1.2ml of cement. These slides can be retrieved under Electronic Supplementary Material.

Evaluation of physico-chemical properties, time of hardening and draining of an endodontic sealer added to mta in different proportions

Objetivo: o objetivo desta pesquisa foi avaliar o tempo e o fluxo de endurecimento do cimento AH-PLUS e MTA nas proporções de 10%, 20% e 30%, a fim de adicionar a capacidade de estimular a deposição de tecido duro. Material e Métodos: Para o teste de fluxo, 0,5 ml de cimento foram depositados em uma placa de vidro e outra placa foi adicionada com uma carga adicional, após 10 minutos a carga foi removida e o diâmetro do círculo formado pelo cimento foi medido com um Bússola digital. Para o tempo de endurecimento, foram utilizados moldes cilíndricos preenchidos com o cimento testado, mantidos dentro de um forno e os testes de agulha de Gillmore foram realizados no material em intervalos de 60 segundos até que as marcas não fossem visíveis na superfície do cimento testado. Resultados: Na vazão, os valores obtidos foram: 41,1 mm (10% MTA), 32,86 mm (20% MTA), 21,91 mm (30% MTA), 24,41 mm AHPlus® e 26,47 mm MTA Fillapex®. O tempo de endurecimento encontrado nesta pesquisa foi de 1631 'em proporção (10% MTA), 628,4 em proporção (20% MTA), 567' em proporção (30% MTA), 767 em AH Plus e Fillapex MTA não. presou dentro de 6 semanas. Conclusão: concluiu-se que a adição de 10%, 20% e 30% de MTA ao AH Plus não alterou as propriedades do fluxo e o tempo estabelecido.

New approaches for cement-based prophylactic augmentation of the osteoporotic proximal femur provide enhanced reinforcement as predicted by non-linear finite element simulations

BackgroundHigh incidence and increased mortality related to secondary, contralateral proximal femoral fractures may justify invasive prophylactic augmentation that reinforces the osteoporotic proximal femur to reduce fracture risk. Bone cement-based approaches (femoroplasty) may deliver the required strengthening effect; however, the significant variation in the results of previous studies calls for a systematic analysis and optimization of this method. Our hypothesis was that efficient generalized augmentation strategies can be identified via computational optimization. MethodsThis study investigated, by means of finite element analysis, the effect of cement location and volume on the biomechanical properties of fifteen proximal femora in sideways fall. Novel cement cloud locations were developed using the principles of bone remodeling and compared to the “single central” location that was previously reported to be optimal. FindingsThe new augmentation strategies provided significantly greater biomechanical benefits compared to the “single central” cement location. Augmenting with approximately 12ml of cement in the newly identified location achieved increases of 11% in stiffness, 64% in yield force, 156% in yield energy and 59% in maximum force, on average, compared to the non-augmented state. The weaker bones experienced a greater biomechanical benefit from augmentation than stronger bones. The effect of cement volume on the biomechanical properties was approximately linear. Results of the “single central” model showed good agreement with previous experimental studies. InterpretationThese findings indicate enhanced potential of cement-based prophylactic augmentation using the newly developed cementing strategy. Future studies should determine the required level of strengthening and confirm these numerical results experimentally.

A Novel Implant for the Prophylactic Treatment of Impending Pathological Fractures of the Proximal Femur: Results from a Prospective, First-in-Man Study.

To prospectively evaluate a novel implant, Y-STRUT® (Hyprevention, Pessac, France), designed to provide prophylactic reinforcement of the proximal femur in metastatic patients. Ten patients presenting lytic lesions of the proximal femur were to be treated. The device consisted of two components implanted in the proximal femur, combined with bone cement. Patients were followed at 2, 6 and 12months to record technical feasibility, safety and efficacy parameters of the procedure. All patients (62years, 67% male) presented a pertrochanteric lesion shown on imaging with an average Mirels' score of 9.42 (range 8-11). Procedures were performed by interventional radiologists, under general anesthesia in 97±28min, with 9.2±3.1ml of cement injected. Hospitalization duration was 2.3±1.4days. A median follow-up of 237days (range 24-411) was reported. Wound healing was achieved in all patients, with no case of wound infection, bleeding, leakage or inflammation. Among the patients evaluated, 86% could resume walking at hospital discharge. Visual Analogue Scale decreased from 3.6±2.9 before treatment to 1.3±0.8 at 1year. OHS-12 score increased from 30±10 at baseline to 37±6 at 1year. Results from this first-in-man study conducted in patients with metastatic bone disease show the feasibility and the safety of the intervention, with a short hospitalization, when performed following the operating instructions. Initial data showing pain-level diminution and increase in OHS-12 score indicate that both symptomatic and functional conditions of the patients were improved 1year after the implantation of this novel implant. Level 4, Case Series.

Biomechanical Analysis of Intervertebral Cement Extravasation in Vertebral Motion Segments.

Kyphoplasty is a therapeutic option for pain relief in the setting of compression fractures. Cement extravasation into adjacent disks is a common occurrence. The biomechanical and clinical consequences of cement in the disks currently are unknown. This study investigated the biomechanical effects of cement extravasation into the intervertebral disk in a human cadaveric model. Seven thoracolumbar and lumbar embalmed human cadaveric motion segments were evaluated in axial rotation, right and left lateral bending, and flexion and extension. Stiffness was calculated at baseline and following injection of 1 mL of cement into the intervertebral disk. There was a 13.4% (P=.041) increase in stiffness in axial rotation compared with preinjection motion segments. No significant difference was observed in lateral bending or flexion and extension. In this model, cement extravasation into the disk space increased stiffness in axial rotation. [Orthopedics. 2017; 40(2):e300-e304.].

Percutaneous Vertebroplasty: A New Technique Minimizing Cement Leak

Introduction Since the introduction of vertebroplasty to clinical practice, the cement leak is considered the most frequent and hazardous complication. In literature, the cement extravasation ranged from 26 to 97% of the time. This study discussed a new technique for injecting cement in the affected vertebra. Patients and Methods A total of 123 patients were treated by vertebroplasty using the current technique. The package of the cement powder and the solvent was divided into five equal parts. Each part of the powder and the solvent was mixed as a single dose and injected to the affected vertebra. The duration between subsequent injections was 10 minutes. Each injection is formed of 1 to 1.5 mL of cement. Results This new technique gives the surgeon enough time to make multiple separate injections with the same package. The time interval between injections makes cement harden enough and makes it not pushed by the next cement injection. This technique of injection gives time to the injected cement to seal off the cracks and cavities in the vertebra and subsequently leads to a highly significant decreased in cement leak ( p &lt; 0.001) compared with the literature. Conclusion This study demonstrates a previously unreported technique for vertebroplasty that adds more safety to the procedure by significantly decreasing cement leak. It also gives the surgeon much more relaxation time and self-confidence during performing the procedure.

Minimum cement volume for vertebroplasty.

Percutaneous vertebroplasty is a widely used vertebral augmentation technique. It is a minimally invasive and low-risk procedure, but has some disadvantages with a relatively high number of bone cement leaks and adjacent vertebral fractures. The aim of this cadaveric study was to determine the minimum percentage of cement fill volume in vertebroplasty needed to restore vertebral stiffness and adjacent intradiscal pressure. Thirteen thoracolumbar spine mobile segments were loaded to induce a vertebral fracture. After fracture vertebroplasty was performed, four times in the same fractured vertebra. The injected cement volume was 5 % of the fractured vertebral volume to reach 5, 10, 15 and 20 % of cement fill. Biomechanical testing was performed before the fracture, after the fracture and after each cement injection. After vertebral fracture compressive stiffness was reduced to 47 % of the pre-fracture value and was partially restored to 61 % after 10 % cement fill. With vertebroplasty intradiscal pressure gradually increased, depending on specimen position, from 48 to a total of 71 % at 15 % of cement fill. Compressive stiffness and intradiscal pressure increase with the percentage of cement fill. Fifteen per cent of cement fill was the limit beyond which no substantial increase in compressive stiffness or intradiscal pressure could be detected and is the minimum volume of cement we recommend for vertebroplasty. In the average thoracolumbar vertebra this means 4-6 ml of cement.

Subject-specific planning of femoroplasty: An experimental verification study

The risk of osteoporotic hip fractures may be reduced by augmenting susceptible femora with acrylic polymethylmethacrylate (PMMA) bone cement. Grossly filling the proximal femur with PMMA has shown promise, but the augmented bones can suffer from thermal necrosis or cement leakage, among other side effects. We hypothesized that, using subject-specific planning and computer-assisted augmentation, we can minimize cement volume while increasing bone strength and reducing the risk of fracture. We mechanically tested eight pairs of osteoporotic femora, after augmenting one from each pair following patient-specific planning reported earlier, which optimized cement distribution and strength increase. An average of 9.5(±1.7) ml of cement was injected in the augmented set. Augmentation significantly (P<0.05) increased the yield load by 33%, maximum load by 30%, yield energy by 118%, and maximum energy by 94% relative to the non-augmented controls. Also predicted yield loads correlated well (R2=0.74) with the experiments and, for augmented specimens, cement profiles were predicted with an average surface error of <2mm, further validating our simulation techniques. Results of the current study suggest that subject-specific planning of femoroplasty reduces the risk of hip fracture while minimizing the amount of cement required.

Radiofrequency sacroplasty (RFS) for the treatment of osteoporotic insufficiency fractures

In elderly patients with reduced bone quality, insufficiency fractures of the sacrum are relatively common and are typically accompanied by severe, disabling pain. The objective of this study was to evaluate the feasibility of cement augmentation by RFS, as well as to determine postinterventional leakages and present the patients' outcomes. In 20 patients (18 women, 2 men) with an average age of 80.4 (65-92) years, a fracture of the sacrum was detected by CT and MRI. Clinically manifest osteoporosis with QCT values of below 50 mg/ml was found in all patients. An initially performed conservative treatment over a period of 3 weeks did not achieve a satisfactory reduction in the severe, disabling pain. The cement augmentation was performed under CT guidance by means of RFS under intubation anaesthesia. A Jamshidi needle was advanced into the respective fracture zone in the sacrum from dorsal to ventral (short axis) or from lateral to medial transiliac (transiliac axis). After removing the inner needle, a flexible osteotome was inserted through the positioned hollow needle and used to extend the spongious space in the fracture zone and thus prepare a cavity for the cement filling. The highly viscous polymethyl methacrylate (PMMA) cement, activated by radiofrequency, was then inserted into the prepared fracture zone through a substituted screw cannula. Cement filling was performed discontinuously under instrumental guidance at 1.3 ml/min under CT guidance. Cement leakages were determined in CT images and conventional X-rays on the day after the intervention. Pain was documented on a visual analogue scale (VAS) on the day before the intervention, on the second day, and after 6 and 12 months after the intervention. Additionally occurring complications were recorded, and the patients were asked to state how satisfied they were after 12 months. RFS was technically feasible in all patients. In the control CT scans and X-rays, sufficient cement distribution and interlocking with vital bone was found along the course of the fracture in the sacrum. 7.2 (4-9) ml of cement were inserted per fracture. Leakage could be ruled out. The mean pain score on the VAS was 8.8 ± 1.2 before the intervention, and a significant reduction in pain (p < 0.001) was seen on the second postoperative day, with an average value of 2.3 ± 0.7, which was stable at 2.2 ± 1.3 after 6 months and 2.1 ± 1.1 after 12 months. All of the patients could be fully re-mobilised and discharged back home. A high level of patient satisfaction was found after 12 months, with 18 of the 20 patients stating that they would undergo the intervention again. One patient died of a stroke, another of cancer over the course. As a minimally invasive procedure, RFS is an effective and safe method of treatment for rapid, significant and sustained pain reduction.

Subject-specific planning of femoroplasty: A combined evolutionary optimization and particle diffusion model approach

A potential effective treatment for prevention of osteoporotic hip fractures is augmentation of the mechanical properties of the femur by injecting it with agents such as (PMMA) bone cement – femoroplasty. The operation, however, is only in research stage and can benefit substantially from computer planning and optimization. We report the results of computational planning and optimization of the procedure for biomechanical evaluation. An evolutionary optimization method was used to optimally place the cement in finite element (FE) models of seven osteoporotic bone specimens. The optimization, with some inter-specimen variations, suggested that areas close to the cortex in the superior and inferior of the neck and supero-lateral aspect of the greater trochanter will benefit from augmentation. We then used a particle-based model for bone cement diffusion simulation to match the optimized pattern, taking into account the limitations of the actual surgery, including limited volume of injection to prevent thermal necrosis. Simulations showed that the yield load can be significantly increased by more than 30%, using only 9ml of bone cement. This increase is comparable to previous literature reports where gross filling of the bone was employed instead, using more than 40ml of cement. These findings, along with the differences in the optimized plans between specimens, emphasize the need for subject-specific models for effective planning of femoral augmentation.

Safety and Efficacy of Percutaneous Vertebroplasty and Interventional Tumor Removal for Metastatic Spinal Tumors and Malignant Vertebral Compression Fractures

The purpose of this study was to determine the safety and efficacy of percutaneous vertebroplasty and interventional tumor removal in the management of metastatic spinal tumors and malignant vertebral compression fractures. Thirty-one patients with metastatic spinal tumors and malignant vertebral compression fractures were treated with percutaneous vertebroplasty and interventional tumor removal. Insertion of a 14-gauge needle and guidewire into the vertebral body was followed by sequential dilation of the track with working cannulae until the last cannula reached the anterior portions of the pedicle. Interventional tumor removal was performed with marrow nucleus rongeurs, and 5-10 mL of cement was injected into the treated vertebra. Outcome data (visual analog scale score, Oswestry disability index score, and Karnofsky performance scale score) were collected preoperatively; 1 week and 1, 3, and 6 months after the procedure; and every 6 months thereafter until death. The overall clinical assessment at the last follow-up evaluation showed that pain was completely resolved in 23 patients, decreased in six patients, and unimproved in two patients, yielding a pain relief rate of 94%. The average preoperative visual analog scale score was 7.2, which decreased to 2.4 at 1 month, 1.9 at 6 months, and 1.6 at 1 year and was maintained at 1.3 at the follow-up evaluations performed after more than 1 year. Statistically significant improvement in Oswestry disability index and Karnofsky performance scale scores was also seen between the preoperative evaluation and every follow-up assessment postoperatively (p<0.001). Percutaneous vertebroplasty and interventional tumor removal are safe, effective, and minimally invasive palliative therapies for reducing pain and improving function in patients with metastatic spinal tumors and malignant vertebral compression fractures.

Long-term results of the augmented PFNA: a prospective multicenter trial

Pertrochanteric fractures are increasing and their operative treatment remains under discussion. Failures needing reoperations such as a cut-out are reported to be high and are associated with multiple factors including poor bone quality, poor fracture reduction and improper implant placement. The PFNA(®) with perforated blade offers an option for standardized cement augmentation with a PMMA cement to provide more stability to the fracture fixation. It remains unclear if the augmentation of this implant does any harm in a longer time span. This prospective multicenter study shows clinical and radiological results with this implant with a mean follow-up time of 15 months. In 5 European clinics, 62 patients (79 % female, mean age 85.3 years) suffering from an osteoporotic pertrochanteric fracture (AO 31) were treated with the augmented PFNA(®). The primary objectives were assessment of activities of daily living, pain and mobility. Furthermore, the X-rays were analyzed for the cortical thickness index, changes of the trabecular structure around the cement and the hip joint space. The mean follow-up time was 15.3 months. We observed callus healing in all cases. The surgical complication rate was 3.2 % with no complication related to the cement augmentation. A mean volume of 3.8 ml of cement was injected and no complication was reported due to this procedure. 59.9 % reached their prefracture mobility level until follow-up. The mean hip joint space did not change significantly until follow-up and there were no signs of osteonecrosis in the follow-up X-rays. Furthermore, no blade migration was assessed. This study makes us believe that the standardized augmentation of the PFNA with a perforated blade is a safe method to treat pertrochanteric femoral fractures. It leads to good functional results and is not associated with cartilage or bone necrosis.

Percutaneous vertebroplasty at C7 for the treatment of painful metastases -A case report-

The cervical spine is a less common site for metastatic disease than is the thoracolumbar spine. Percutaneous vertebroplasty (PVP) in the cervical spine can be performed using an anteromedial or lateral approach. A 51-year-old woman with breast cancer had been experiencing severe weight-bearing neck pain for 2 months, even after undergoing radiation therapy. Imaging studies revealed an osteolytic compression fracture in the C7 vertebra. For performing PVP at C7 using the anteromedial approach, a needle was inserted from the left side of the patient's neck. The needle was advanced to the anterior 1/3 anterior 1/3 or 1/2 of the vertebral body by hammering, and approximately 2 ml of cement was injected. Immediately after the operation, the patient could move her neck without pain. In conclusion, PVP using an anterolateral approach may be an option for treating metastatic osteolytic vertebral lesions in the cervical spine for alleviating intractable axial neck pain.

Evaluation of Radiopacity, pH, Release of Calcium Ions, and Flow of a Bioceramic Root Canal Sealer

IntroductionThe aim of the present study was to evaluate the physicochemical properties of a bioceramic root canal sealer, Endosequence BC Sealer. Radiopacity, pH, release of calcium ions (Ca2+), and flow were analyzed, and the results were compared with AH Plus cement. MethodsRadiopacity and flow were evaluated according to ISO 6876/2001 standards. For the radiopacity analysis, metallic rings with 10-mm diameter and 1-mm thickness were filled with cements. The radiopacity value was determined according to radiographic density (mm Al). The flow test was performed with 0.05 mL of cement placed on a glass plate. A 120-g weight was carefully placed over the cement. The largest and smallest diameters of the disks formed were measured by using a digital caliper. The release of Ca2+ and pH were measured at periods of 3, 24, 72, 168, and 240 hours with spectrophotometer and pH meter, respectively. Data were analyzed by analysis of variance and Tukey test (P < .05). ResultsThe bioceramic endodontic cement showed radiopacity (3.84 mm Al) significantly lower than that of AH Plus (6.90 mm Al). The pH analysis showed that Endosequence BC Sealer showed pH and release of Ca2+ greater than those of AH Plus (P < .05) during the experimental periods. The flow test revealed that BC Sealer and AH Plus presented flow of 26.96 mm and 21.17 mm, respectively (P < .05). ConclusionsEndosequence BC Sealer showed radiopacity and flow according to ISO 6876/2001 recommendations. The other physicochemical properties analyzed demonstrated favorable values for a root canal sealer.