Viscosity Bone Cement Research Articles

Randomized controlled trial comparing traditional versus enhanced-fixation designs of a novel cemented total knee arthroplasty tibial component.

A novel enhanced cement fixation (EF) tibial implant with deeper cement pockets and a more roughened bonding surface was released to market for an existing total knee arthroplasty (TKA) system.This randomized controlled trial assessed fixation of the both the EF (ATTUNE S+) and standard (Std; ATTUNE S) using radiostereometric analysis. Overall, 50 subjects were randomized (21 EF-TKA and 23 Std-TKA in the final analysis), and had follow-up visits at six weeks, and six, 12, and 24 months to assess migration of the tibial component. Low viscosity bone cement with tobramycin was used in a standardized fashion for all subjects. Patient-reported outcome measure data was captured at preoperative and all postoperative visits. The patient cohort mean age was 66 years (SD seven years), 59% were female, and the mean BMI was 32 kg/m2 (SD 6 kg/m2). Mean two-year subsidence of the EF-TKA was 0.056 mm (95% confidence interval (CI) 0.025 to 0.086) versus 0.006 mm (95% CI -0.029 to 0.040) for the Std-TKA, and the two-year maximum total point motion (MTPM) was 0.285 mm (95% upper confidence limit (UCL) ≤ 0.363) versus 0.346 mm (95% UCL ≤ 0.432), respectively, for a mean difference of -0.061 mm (95% CI -0.196 to 0.074). Inducible displacement also did not differ between groups. The MTPMs between 12 and 24 months for each group was below the published threshold of 0.2 mm for predicting early aseptic loosening (p < 0.001 and p = 0.001, respectively). Both the enhanced fixation and the standard tibial implant design showed fixation with a predicted low risk of long-term aseptic loosening.

A new mathematical model of compressive stress-strain behaviour of low viscosity and high viscosity bone cement with different strain rates

A new mathematical model of compressive stress-strain behaviour of low viscosity (LV) and high viscosity (HV) bone cement has been proposed to capture large uniaxial deformation under constant applied strain rate by incorporating three-term power law. The modeling capacity of the proposed model has been validated using uniaxial compressive test under eight different low strain rates ranging from 1.39 × 10-4 s-1 to 3.53 × 10-2 s-1 for low viscosity and high viscosity bone cement. The well agreement between the model and experimental response suggests that the proposed model can successfully predict rate dependent deformation behavior for Poly(methyl methacrylate) (PMMA) bone cement. Additionally, the proposed model was compared with the generalized Maxwell viscoelastic model and found to be in good agreement. The comparison of compressive responses over low strain rates for LV and HV bone cement reveals their rate-dependent compressive yield stress behaviour along with a higher value of compressive yield stress of LV bone cement compared to HV bone cement. For example, at the strain rate of 1.39 × 10-4 s-1 the mean value of compressive yield stress of LV bone cement was found to be 64.46 MPa, whereas for HV bone cement it was 54.00 MPa. Moreover, the modeling of experimental compressive yield stress with the Ree-Eyring molecular theory suggests that the variation of yield stress of PMMA bone cement can be predicted using two processes Ree-Eyring theory. The proposed constitutive model might be useful to characterize large deformation behaviour with high accuracy for PMMA bone cement. Finally, both variants of PMMA bone cement also exhibit ductile-like compressive behaviour below the strain rate of 2.1 × 10-2 s-1, whereas above this threshold strain rate, brittle-like compressive failure behavior is observed.

Clinical application of targeted sealing with high viscosity bone cement and secondary injection of low viscosity bone cement in vertebroplasty

To observe the clinical efficacy of targeted sealing with high viscosity bone cement and secondary injection of low viscosity bone cement in the treatment of OVCFs patients with the fracture lines involved vertebral body margin. The elderly patients who underwent vertebroplasty for osteoporotic vertebral compression fractures from January 2019 to September 2021 were selected as the screening objects. Through relevant standards and further CT examination, 56 patients with fracture lines involving the anterior wall or upper and lower endplates of the vertebral body were selected for the study. There were 21 males and 35 females, aged from 67 to 89 years old with an average of (76.58±9.68) years. All 56 patients underwent secondary injection of bone cement during operation. Only a small amount of high viscosity cement was targeted to seal the edge of the vertebral body for the first time, and low viscosity cement was injected to the vertebral bodies during second bolus with well-distributed. The operation time, bone cement volume and bone cement leakage were recorded, and the pain relief was evaluated by visual analogue scale (VAS). All patients were followed up for more than 3 months and the surgeries were successfully complete. The operation time was (50.41±10.30) min and the bone cement volume was (3.64±1.29) ml. The preoperative VAS was (7.21±2.41) points, which decreased significantly to (2.81±0.97) points 3 days after operation(P<0.05). Among the 56 patients, 2 cases(3.57%) had bone cement leakage, 1 case leaked to the paravertebral vein, and 1 case slightly bulged to the paravertebral through the crack when plugging the vertebral crack. Both patients had no obvious clinical symptoms. In vertebroplasty surgery, targeted sealing of high viscosity bone cement and secondary injection of low viscosity bone cement can reduce intraoperative bone cement leakage and improve the safety of operation.

Risk factors for bone cement displacement after percutaneous vertebral augmentation for osteoporotic vertebral compression fractures.

PurposeTo explore the risk factors of bone cement displacement after percutaneous vertebral augmentation (PVA) in patients with osteoporotic vertebral compression fracture (OVCF).MethodsWe retrospectively reviewed the records of 1,538 patients with OVCF treated with percutaneous vertebroplasty (PVP) or percutaneous vertebroplasty (PKP) from January 2016 to June 2021. Patients were divided into bone cement displacement group (n = 78) and bone cement non-displacement group (n = 1,460) according to the radiographic images. Possible risk factors for bone cement displacement were noted, including age, gender, body mass index (BMI), bone mineral density (BMD), underlying disease, number of fractured vertebrae, involved vertebral segment, surgical method, surgical approach, vertebral height, Cobb angle, cement leakage, the viscosity of bone cement, bone cement diffuse ratio, degree of bone cement interweaving, sagittal bone cement placement, targeted location of bone cement, the distance between the bone cement and the upper and lower endplates, the time of wearing brace and postoperative osteoporosis treatment. Risk factors were identified with univariate and multivariate logistic regressions and the discrimination ability of the predictive indicators was evaluated using area under the curve (AUC) of the receiver operating characteristic (ROC).ResultsIn multivariate regression, independent risk factors for bone cement displacement included: high restoration of Cobb angle (OR = 2.019, 95%[CI] 1.545–4.852, P < 0.001), cement leakage (anterior edge) (OR = 1.727, 95%[CI] 1.05–2.20, P < 0.001), small degree of bone cement interweaving (OR = 1.917, 95%[CI] 1.129–2.747, P < 0.001), non-targeted location of bone cement (OR = 2.323, 95%[CI] 1.645–4.134, P < 0.001), short duration of brace wearing (OR = 3.207, 95%[CI] 2.036–4.348, P < 0.001) and postoperative osteoporosis treatment (OR = 0.422, 95% CI = 0.323–0.547, P < 0.001). The AUCs for the high restoration of Cobb angle, cement leakage (anterior edge), small degree of bone cement interweaving, non-targeted location of bone cement, short duration of brace wearing and non-postoperative osteoporosis treatment were 0.784 (95% CI, 0.747–0.821), 0.811 (95% CI 0.764–0.859), 0.917 (95%CI 0.864–0.970), 0.610 (95%CI 0.552–0.669), 0.854 (95%CI 0.816–0.892) and 0.756 (95% CI, 0.712–0.800), respectively.ConclusionHigh restoration of Cobb angle, cement leakage (anterior edge), small degree of bone cement interweaving, non-targeted location of bone cement, short duration of brace wearing and non-postoperative osteoporosis treatment were the independent risk factors of bone cement displacement after PVA.

Effects of high viscosity bone cement percutaneous vertebroplasty on pain, bone specific alkaline phosphatase, Type-I collage cross-linked-telopeptide and Boneglaprotein levels in patients with osteoporotic vertebral compression fractures.

Objectives:To investigate the effects of percutaneous vertebroplasty with high viscosity bone cement on pain and the levels of bone specific alkaline phosphatase (BALP), Type-I collagen cross-linked telopeptide (CTX) and serum osteocalcin (BGP) in patients with osteoporotic vertebral compression fractures.Methods:The medical records of patients with osteoporotic vertebral compression fractures treated in our hospital from February 2020 to February 2021 were selected after retrospective analysis. Patients (43) who received low viscosity bone cement percutaneous vertebroplasty comprised Group-I, and patients (56) who received high viscosity bone cement percutaneous vertebroplasty, comprised Group-II of the study. The occurrence of bone cement leakage, pain (VAS scores), BALP, CTX and BGP were compared and analyzed between the two groups.Results:The incidence of bone cement leakage in Group-II was 16.28%, lower than 3.57% in Group-I (P<0.05). The visual analogue scale (VAS) scores of patients in Group-II were lower than those in Group-I at one and three months after the surgery (P<0.05). The levels of BALP and BGP in Group-II were higher than those in Group-I three months after the surgery (P<0.05), and CTX was lower than those in Group-I (P<0.05).Conclusions:Percutaneous vertebroplasty with high viscosity bone cement in the treatment of osteoporotic vertebral compression fractures can reduce the incidence of bone cement leakage and help to further reduce pain and improve bone metabolism.

Kyphoplasty with high viscosity bone cement for the treatment of stage III Kümmell disease without neurological symptoms: restoration of vertebral body height, reduction of kyphoplasty and restoration of column sagittal sequence.

BACKGROUND: Percutaneous kyphoplasty is widely used in the treatment of stage I and II Kummell disease, which can rapidly relieve pain, stabilize vertebral body and correct kyphosis;however, the treatment of stage III Kummell disease is still controversial. OBJECTIVE: To evaluate the clinical outcome of kyphoplasty with high-viscosity bone cement for treatment of stage III Kummell disease without neurologic symptoms. METHODS: Twenty-eight patients (11 males and 17 females, aged 57-82 years) with stage III Kummell disease without neurologic symptoms were admitted to Jiangyin People’s Hospital from May 2016 to May 2019, in which T11 vertebral body in 6 cases and T12 vertebral body in 14 cases, L1 vertebral body in 5 cases and L2 vertebral body in 3 cases were treated by kyphoplasty with high viscosity bone cement. At 1 day after operation and 1 year after follow up, postoperative pain and improvement of life ability were evaluated by the Visual Analogue Scale and Oswestry Disability Index. The recovery of vertebral height and correction of kyphosis were measured with X-ray films. The study was approved by the Ethics Committee of Jiangyin People’s Hospital, approval No. [2017](021). RESULTS AND CONCLUSION: (1) Totally 28 patients were followed up for 12-22 months. No serious complications such as wound infection or pulmonary embolism were found during treatment. Asymptomatic cement leakage occurred in three patients. Adjacent vertebral fracture was encountered in 1 patient at 3 months after operation, and healed after kyphoplasty. (2) Visual Analogue Scale, Oswestry Disability Index, and kyphotic angle were lower at 1 day and 1 year after operation than those before operation in 28 patients (P < 0.05). The height of anterior, middle and posterior edges of vertebral body at 1 day and 1 year after operation was higher than that before operation (P < 0.05). (3) The results showed that kyphoplasty with high-viscosity bone cement can relieve back pain, improve viability, retain the vertebral body height, reduce kyphosis, and restore spinal alignment, and is an effective method for treatment of stage III Kummell disease. (English) [ABSTRACT FROM AUTHOR] 背景：经皮球囊扩张椎体后凸成形能够快速缓解疼痛、稳定椎体、矫正脊柱后凸畸形，被广泛用于Ⅰ期、Ⅱ期Kummell病的治疗，但对于 Ⅲ期Kummell病的治疗方法目前尚存在争议。 目的：探讨高黏度骨水泥椎体后凸成形治疗无神经症状Ⅲ期Kummell病的疗效。 方法：选择2016年5月至2019年5月江阴市人民医院收治的无神经症状Ⅲ期Kummell病患者28例，其中男11例，女17例，年龄57-82岁；病 变椎体集中于胸腰段，其中T11椎体6例，T12椎体 14例，L1椎体5例，L2椎体3例，均接受高黏度骨水泥椎体后凸成形治疗。术后1 d及1年随 访时，采用目测类比评分和Oswestry功能障碍指数评价患者术后疼痛和生活能力改善情况，拍摄正、侧位X射线片测量椎体高度恢复和后 凸畸形矫正情况。研究获得江阴市人民医院伦理委员会批准，批件号：[2017]伦审研第(021)号。 结果与结论：①28例患者均顺利完成手术并完成随访，随访12-22个月，治疗过程中未出现伤口感染、肺栓塞等严重并发症，3例发生骨 水泥椎间隙渗漏，未引起临床症状；1例术后3个月出现邻近椎体骨折，行椎体后凸成形治疗后治愈；②28例患者术后1 d、术后1年时的目 测类比评分、Oswestry功能障碍指数评分与局部后凸角均低于术前(P < 0.05)，术后1 d、术后1年时的椎体前缘、中间及后缘高度均高于术 前(P < 0.05)；③结果表明，高黏度骨水泥椎体后凸成形可有效缓解患者腰背痛、改善患者生活能力、恢复椎体高度、减小后凸畸形、恢复 脊柱矢状序列，是治疗无神经症状Ⅲ期Kummell病的有效方法之一. (Chinese) [ABSTRACT FROM AUTHOR] Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo zu zhi gong cheng yan jiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High viscosity bone cement vertebroplasty versus low viscosity bone cement vertebroplasty in the treatment of mid-high thoracic vertebral compression fractures

BACKGROUND CONTEXTAs science and technology have advanced, novel bone cements with numerous formulated ingredients have greatly evolved and been commercialized for vertebroplasty. Recently, viscosity has been a focus to achieve better clinical outcomes and fewer complications. Meanwhile, the experience in the treatment of mid (T7–9) to high (T4–6) thoracic vertebral compression fractures is limited. PURPOSEThe objective of this study was to identify the different outcomes between high-viscosity bone cement (HVBC) and low-viscosity bone cement (LVBC) used to repair mid (T7–9)- and high (T4–6)- thoracic vertebral compression fractures. STUDY DESIGN/SETTINGThis study was a single-center, retrospective cohort study PATIENT SAMPLEA consecutive series of 107 patients with a total of 144 vertebrae was included. OUTCOME MEASURESThe anterior vertebral height (AVH), middle vertebral height (MVH), posterior vertebral height (PVH), local kyphotic angle (KA), Cobb angle (CA), and other associated parameters were evaluated radiologically at several time points—preoperative, surgery day 0, postoperative day 1, and 6-month follow-up. Pain evaluation was assessed by using a visual analog scale (VAS) before and 6 months after the procedure. METHODSThe patients were divided into two groups according to the viscosity of the bone cement used, and plain film and magnetic resonance imaging (MRI) of the vertebrae were used to calculate parameters. The patient characteristics; bone cement brand; changes in AVH, MVH, PVH, KA, CA, and VAS; and complications of each patient were recorded and then analyzed. RESULTSBoth groups showed increased vertebral body height, corrected KA, and CA after vertebroplasty. There were no significant differences between the HVBC and LVBC groups (ΔAVH: 2.19±2.60 vs. 2.48±3.09, p=.555; ΔMVH: 1.25±3.15 vs. 1.89±2.58, p=.192; ΔKA: -5.46±4.58 vs -5.37±4.47, p=.908; and ΔCA: -4.22±4.23 vs. -4.56±5.17, p=.679). There were significant preoperative to postoperative and preoperative to follow-up changes in AVH (HVBC, p=.012 and .046, respectively; LVBC, p=.001 and .015, respectively); a significant preoperative to postoperative change in MVH (HVBC, p=.045; LVBC, p=.001); and significant preoperative to postoperative and preoperative to follow-up changes in KA and CA (KA: HVBC, p=0.000 and .003, respectively; LVBC, p=.000 and .000, respectively; CA: HVBC, p=.017 and .047, respectively; LVBC, p=.006 and .034, respectively). The volume of cement injected was significantly higher with HVBC (3.66±1.36 vs. 3.11±1.53, p=.024), and the use of HVBC was associated fewer cases with cement leakage (26 vs. 45, p=.002). Furthermore, there was no difference between the groups in the incidence of adjacent fracture. Both groups showed an improved VAS score at follow-up, with statistically greater improvement in the HVBC group (2.40±1.53 vs. 3.07±1.69, p=.014). Moreover, significantly fewer patients with a VAS score ≥ 3 were found in the HVBC group (22 vs. 39, p=.004) CONCLUSIONSHVBC and LVBC are safe and effective to treat mid-to-high level thoracic vertebral compression fractures. Compared with LVBC, HVBC shows less cement leakage, a greater injection volume, and better postoperative pain relief.

Overview of research work of Prof. Chu on two medical devices

Surgical procedures are relatively common and procedures for broken bones often involve intramedullary nailing to repair the bone and keep it stable. However, there are challenges associated with the process and Professor Woeichyn Chu, who is a distinguished professor based within the Department of Biomedical Engineering at the National Yang Ming Chiao Tung University in Taiwan, is developing a medical device to help surgeons overcome these challenges, benefiting patients and clinicians. The device is called iMET (intra-medullary endo-transilluminating) and came about after Woeichyn Chu spoke with his brother, Dr William Chu, General Orthopedic Department, Cheng Hsin General Hospital, Taiwan, about some of the challenges relating to intramedullary nailing which led the brothers to begin working together to develop a medical device to help target distal locking holes in intramedullary nailing procedures. The iMET device that the brothers are developing is designed to improve target aiming accuracy and reduce dose absorption concerns. In the process, it will save significant time, effort and money. As well as benefiting patients and clinicians, iMET also reduces X-ray fluoroscopy time, which has health benefits for all involved. Woeichyn Chu and his brother are also developing a device called iKypho, which applies negative pressure during bone cement injection in percutaneous vertebroplasty surgeries. iKypho reduces bone cment leakage risks when using low viscosity cement and reducing the costs associated with high viscosity bone cement.

The effect of bone cement on the curative effect of percutaneous kyphoplasty in the treatment of osteoporotic vertebral compression fracture.

To investigate the effect of bone cement on the curative effect of percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fracture (OVCF). A total of 323 patients with OVCF who underwent PKP in our hospital between January 2018 and June 2020 were enrolled. According to the viscosity and distribution of the bone cement, the patients were divided into a high viscosity (HV) group and a low viscosity (LV) group, and into a central distribution (central) group and a lateral distribution (lateral) group, and their baseline characteristics, perioperative parameters, efficacy indicators, and complications indicators were compared. In the HV group, the amount of bone cement injected and the number of patients with centrally distributed bone cement were significantly higher than those in the LV group, while the operation time and the number of patients with laterally distributed bone cement were significantly lower. Further, the bone cement viscosity in the central group was significantly higher than that in the lateral group. Before surgery, there were no significant differences between the groups in terms of the posterior back visual analog scale (VAS) score, Oswestry dysfunction index (ODI), Cobb angle, vertebral height, or anterior vertebral height (AVH) of the fractured vertebral body. However, after surgery, both the ODI and the Cobb angle were notably reduced and the AVH was increased in the HV group. Meanwhile, in the central group, the VAS, Cobb angle, and ODI were all dramatically reduced. Centrally distributed high-viscosity bone cement can reduce the Cobb angle and the incidence of bone cement leakage in patients with OVCF who undergo PKP, thereby improving the curative effect.

Relationship between the Surface Roughness of Material and Bone Cement: An Increased “Polished” Stem May Result in the Excessive Taper-Slip

Although some reports suggest that taper-slip cemented stems may be associated with a higher periprosthetic femoral fractures rate than composite-beam cemented stems, few studies have focused on the biomaterial effect of the polished material on the stem–cement interface. The purpose of this study was to investigate the relationship between surface roughness of materials and bone cement. Four types of metal discs—cobalt-chromium-molybdenum alloy (CoCr), stainless steel alloy 316 (SUS), and two titanium alloys (Ti-6Al-4V and Ti-15Mo-5Zr-3Al)—were prepared. Five discs of each material were produced with varying degrees of surface roughness. In order to evaluate surface wettability, the contact angle was measured using the sessile drop method. A pin was made using two bone cements and the frictional coefficient was assessed with a pin-on-disc test. The contact angle of each metal increased with decreasing surface roughness and the surface wettability of metal decreased with higher degrees of polishing. With a surface roughness of Ra = 0.06 μm and moderate viscosity bone cement, the frictional coefficient was significantly lower in CoCr than in SUS (p = 0.0073). In CoCr, the low adhesion effect with low frictional coefficient may result in excessive taper-slip, especially with the use of moderate viscosity bone cement.

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.

不同粘度骨水泥治疗老年性骨质疏松椎体压缩骨折的疗效比较

不同粘度骨水泥治疗老年性骨质疏松椎体压缩骨折的疗效比较

Efficacy and safety of high-viscosity cement in percutaneous vertebroplasty for treatment of Osteoporotic vertebral compression fractures: A retrospective cohort study.

To evaluate the efficacy and safety of high viscosity bone cement in the percutaneous vertebroplasty (PVP) for treatment of single-level osteoporotic vertebral compression fractures.Eighty patients were enrolled in this study. All patients were received PVP, and they were divided into 2 groups according to the viscosity of bone cement, either high viscosity bone cement (HV group) or low viscosity cement (LV group). Oswestry Disability Index questionnaire and visual analog scale as clinical assessments were quantified. The operative time and injected bone cement volume were recorded. The anterior vertebral height (AVH) and bone cement leakage were evaluated in the radiograph.No significant difference was observed in the operative time. Both groups showed significant improvements in pain relief and functional capacity status (visual analog scale and Oswestry disability index scores) after surgery. Less bone cement volume was injected into the the injured vertebra in the HV group and statistical significance was found between both groups. In the HV group, there was lower leakage rate and less patients of severe leakage compared with the LV group. However, the correction of AVH showed no significant differences between the 2 groups and no significant loss of AVH was observed in 2 groups.High-viscosity and low-viscosity PVP have the similar effects in improving quality of life and relieving pain. There were lower cement leakage rate and less patients of severe leakage in the PVP with high-viscosity bone cement.

A Comparative Study on the Treatment of Osteoporotic Vertebral Compression Fracture with Different Injection Volumes of High Viscosity Bone Cement in Percutaneous Vertebroplasty

This study was to compare the clinical effect of different injection volumes of high viscosity bone cement in percutaneous vertebroplasty on the treatment of osteoporotic vertebral compression fractures. One hundred and fifty cases of patients with osteoporotic vertebral compression fractures treated in the Third Affiliated Hospital of Soochow University from January 2017 to October 2018 were enrolled and randomly divided into the high dose group (50 cases), the middle dose group (50 cases) and the low dose group (50 cases) according to the injection volumes of high viscosity bone cement in percutaneous vertebroplasty. There were no significant differences on single vertebral operation time and bleeding volume among the 3 groups. After percutaneous vertebroplasty treatment, the visual analogue score and Oswestry disability index were significantly improved 5 days and 12 months later in all 3 groups. However, no significant differences were found on the visual analogue score and Oswestry disability index among these 3 groups before surgery and 5 days and 12 months later. The vertebral height and Cobb angle of injured vertebrae were significantly improved 5 days and 3 months after operation in the all 3 groups. However, the improvement had no correlation with the dose of high viscosity bone cement. After treatment, there were 14, 9 and 2 cases of bone cement leakage in high dose, middle dose and low dose groups, respectively. The leak rates were 28, 18 and 4 % and there were significant differences among the 3 groups. In conclusion, different injection volumes of high viscosity bone cement in percutaneous vertebroplasty all reached a good effect in the treatment of osteoporotic vertebral compression fractures. And low dose could significantly reduce the leakage of bone cement. Therefore, low dose of high viscosity bone cement could be the first choice for the treatment of osteoporotic vertebral compression fractures for its safety.

Efficacy and Safety of High-Viscosity Bone Cement Vertebroplasty in Treatment of Osteoporotic Vertebral Compression Fractures with Intravertebral Cleft

To evaluate and compare clinical outcomes and cement leakage of high-viscosity bone cement versus low-viscosity bone cement vertebroplasty in treating osteoporotic vertebral compression fractures with intravertebral cleft. The study included 72 patients with osteoporotic vertebral compression fractures with intravertebral cleft, who were divided into high-viscosity cement (HVC) (38 cases) and low-viscosity cement (LVC) (34 cases) groups according to the viscosity of bone cement used. Cement leakage, visual analog scale score, Oswestry Disability Index, and kyphotic angle (KA) were evaluated. All patients were followed for at least 12 months. Overall cement leakage rate was 18.4% in the HVC group, lower than the rate of 61.8% obtained in the LVC group. A statistically significant difference was found in the overall cement leakage rate between the groups (P < 0.05). Visual analog scale and Oswestry Disability Index scores were significantly improved after percutaneous vertebroplasty without significant differences between the HVC and LVC groups (P > 0.05). The KA of patients from both groups was also significantly corrected immediately after surgery. Although the KA gradually increased in both groups during the follow-up period, there was no statistically significant difference between the HVC and LVC groups in KA during follow-up (P > 0.05). Percutaneous vertebroplasty using HVC to treat osteoporotic vertebral compression fractures with intravertebral cleft significantly reduces cement leakage and improves the safety of the operation. In terms of clinical efficacy and prevention of augmented vertebral recollapse, HVC may not have obvious advantages.

Comparison of the effects of different viscosities of bone cement on severe osteoporotic vertebral compression fractures

Objective To investigate the influence of low viscosity and high viscosity bone cement in PVP on active function, anatomical index and leakage rate of patients with severe osteoporotic vertebral compression fractures (OVCF). Methods From October 2015 to June 2017, 136 patients with severe OVCF were chosen in the Central Hospital of Yuncheng and randomly divided into two groups according to the digital table, with 68 patients in each group.The control group was given low viscosity bone cement by PVP scheme, and the observation group was given high viscosity bone cement by PVP.The VAS score, ODI score, SF-36 score and kyphosis Cobb angle before and after operation, the recovery rate of injured vertebrae, bone cement injection volume and postoperative cement leakage rate of the two groups were compared. Results There were no statistically significant differences in the VAS score, ODI score and SF-36 score before operation between the two groups(all P>0.05). The VAS score, ODI score and SF-36 score after operation of the control group were (1.90±0.32)points, (30.38±3.52)points, (76.07±9.38)points, respectively, which of the observation group were (1.94±0.34)points, (29.72±3.34)points, (77.10±9.60)points, respectively, which were significantly better than those before operation(control group: t=4.27, 5.01, 4.02; observation group: t=4.21, 4.89, 3.87, all P 0.05). The kyphosis Cobb angle after operation of the observation group was (14.02±2.59)°, which was significantly lower than (16.83±3.31)° of the control group and (27.78±4.09)° before operation (t=4.99, 2.64, all P 0.05). The incidence rate of bone cement leakage in the observation group was 10.29%(7/68), which was significantly lower than that in the control group [30.88%(21/68)](χ2=12.15, P<0.05). Conclusion Low viscosity and high viscosity bone cement in PVP in the treatment of patients with severe OVCF possess the same clinical effects on relieve pain and improve activity and quality of life; but high viscosity bone cement application can efficiently improve the anatomical index of injured vertebrae and avoid postoperative cement leakage. Key words: Fractures, compression; Osteoporosis fractures; Vertebroplasty; Cements oplastyop; Viscosity; Activities of daily living; Anatomy, regional; Controlled clinical trial

Effects of Polymethylmethacrylate Cement Viscosity and Bone Porosity on Cement Leakage and New Vertebral Fractures After Percutaneous Vertebroplasty: A Prospective Study.

Study Design:A prospective randomized study.Objectives:To evaluate the effect of bone cement viscosity as well as of bone porosity on cement leakage during vertebroplasty and to analyze the occurrence of new vertebral fractures after the procedure.Methods:Between April 2012 and December 2013, 60 patients suffering from osteoporotic vertebral fractures underwent vertebroplasty. The patients were randomly assigned into 2 equal groups. High-viscosity cement was used in group A, while low-viscosity cement was used in group B. Patients were followed-up for a minimum of 2 years.Results:Cement leakage occurred in 16 patients in group B (20 vertebral bodies) and in 6 patients in group A (9 vertebral bodies). The difference was statistically significant (χ2 = 2.3, P = .01). Lower T-scores were associated with significantly more cement leakage (t = 3.338, P = .002 in group A, and t = 4.329, P = .000 in group B). Patients with a T-score worse than −1.8 had a significantly higher risk of cement leakage if low-viscosity cement was used (χ2 = 3.25, P = .05). New vertebral fractures occurred in 14 (23%) patients, after a mean of 6.5 ± 5.5 months, 10 patients in group A and 4 in group B. The difference did not reach the statistical significance level (χ2 = 3.354, P = .067). Patients presenting with multiple fractures had a significantly more number of new vertebral fractures (χ2 = 7.464, P = .006).Conclusions:The clinical outcome of vertebroplasty was not influenced by cement viscosity. However, lower cement viscosity and higher degree of osteoporosis were found to be significant risk factors for cement leakage. Furthermore, the number of vertebral body fractures on presentation was a predictor for the occurrence of new fractures postoperatively.

Bone cement modeling for percutaneous vertebroplasty.

Vertebroplasty procedures provide a significant benefit for patients suffering from vertebral fractures. In order to address current issues of vertebroplasty procedures, an injection device able to control the bone cement viscosity has been developed. In addition, this device allows to protect the practitioner by removing him/her from the X-rays area. In this context, a study is first proposed to quantify the bone cement viscosity during its polymerization reaction on a rotational rheometer. These experimental measurements have led to the identification of a complete behavior law that takes into account the simultaneous effects of shear rate, time, and temperature. Based on this preliminary study, this article finally aims to prove the ability of estimating the viscosity of the flowing bone cement on the developed injection system. A final set of experiments validates that the injection device dedicated to vertebroplasty procedures can control the flowing bone cement viscosity by acting on the temperature. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1504-1515, 2019.

Mechanical and elution properties of G3 Low Viscosity bone cement loaded up to three antibiotics

ObjectivePeriprosthetic Joint Infection (PjI) is considered one of the most difficult complication to manage after total knee or hip arthroplasty, with a mean incidence of 1%. Antibiotic loaded bone cement is used as prophylaxis during primary arthroplasty and as local therapy during two-stage revision. The aim of this study is to evaluate the mechanical and elution properties of G3 Low Viscosity Bone Cement (G-21 San Possidonio, Modena, Italy) loaded with different doses of up to three antibiotics (12 specimens). MethodsCompressive Strength, Bending Strength and Bending Modulus were evaluated. Cumulative Vancomycin elution by adding different doses of antibiotics was evaluated. ResultsThe mean Compressive Strength was 81.55 MPa, the mean Bending Strength was 2161.7 MPa, and the mean Bending Modulus was 36.6 MPa. The highest cumulative Vancomycin elution was observed in specimen 12 (1906.9 mg at 2 weeks). This is the first study, at our knowledge, that analysed how cement mechanical properties, and antibiotic elution kinetics, are modified by adding up to three antibiotic. ConclusionThe results obtained in this pilot study using G3 Low-Viscosity Bone Cement, demonstrated that mechanical properties not decrease significantly by adding large doses of antibiotics, while the Vancomycin elution increase until swelled to twice.

Biomechanics and leakage rate of high and low viscosity bone cement after vertebroplasty

Objective To explore the differences of biomechanics and leakage rate in high and low viscosity bone cement after vertebroplasty and to analyze the reasons. Methods Forty-two vertebral bodies were harvested from 6 embalmed cadavers. All specimens were subjected to the X-ray examination to exclude tuberculosis, tumor and other diseases. Thirty-six vertebral specimens with similar bone density were selected. All specimens were selected to make into compression fracture model by the biomechanical machine for further test. The model of compression fracture was divided into two groups randomly: A and B (n=18 each). The group A was injected with low viscosity bone cement and the group B with high viscosity. The biomechanical testing was carried out before the fracture and after cement injection. The cement leakage rate and distribution of cement were assessed with the reference of postoperative CT scan. Results In group A and group B, the maximum vertical load and stiffness after cement injection were (3 761.03±693.55) N, (3 965.31±999.90) N; (472.27±52.05) N/mm, (1 039.38±345.11) N/mm, respectively. After vertebroplasty, the maximum vertical load showed no significant difference between 2 groups. (Z=-0.127, P=0.450), and the stiffness was statistically significant (Z=-5.125, P=0.000). The leakage rate was significantly higher in group A (44.44%) than in group B (11.11%) (P=0.026). Conclusion High viscosity bone cement can increase the stiffness of vertebral body and have little effect on the maximum vertical load in comparison to the low viscosity. Furthermore, the high viscosity significantly decreases the rate of bone cement leakage. Key words: Vertebroplasty; High, low viscosity bone cement; Biomechanics; Bone cement leakage rate