Vertebral augmentation with a novel Vessel-X bone void filling container system and bioactive bone cement

Vesselplasty for the treatment of osteoporotic vertebral compression fractures with peripheral wall damage: a retrospective study

STUDY DESIGN

A retrospective study.

OBJECTIVE

The clinical efficacy of vertebroplasty and kyphoplasty treating osteoporotic vertebral compression fractures (OVCF) has been widely recognized in recent years. However, there are also disadvantages of bone cement leakage (BCL), limited correction of kyphosis and recovery of vertebral height. Nowadays, in view of these shortcomings, vesselplasty has been widely used in clinical practice. The objective of this study is to assess its clinical effect and application value for the treatment of OVCF with peripheral wall damage.

METHODS

62 patients (70 vertebrae) treated for OVCF with peripheral wall damage using vesselplasty retrospectively reviewed. The data collection included operation time, volume of bone cement, relevant surgical complications, visual analog scale (VAS), Oswestry disability index (ODI), vertebral body height and kyphosis Cobb angle.

RESULTS

The volume of bone cement was 3-8 (5.3 ± 1.3) ml. There were 3 vertebrae of BCL (4.3%). VAS and ODI at different time points after operation were decreased compared with before operation (all p < 0.05). There were no statistical differences between VAS or ODI at different postoperative time points (p > 0.05). Vertebral body height and Cobb angle at different time points after operation were improved compared with before operation (all p < 0.05). There were no statistical differences between vertebral body height or Cobb angle at different postoperative time points (all p > 0.05).

CONCLUSIONS

Vesselplasty may reduce the risk of BCL and better control the dispersion of bone cement in the treatment of OVCF. It relieves pain, restores vertebral body height and corrects kyphosis, especially in OVCF with peripheral wall damage. Therefore, vesselplasty is safe and worthy of clinical application.

Lateral-Opening Injection Tool Used in Percutaneous Vertebroplasty to Treat Asymptomatic Osteoporotic Vertebral Burst Fractures: A Retrospective Study

OBJECTIVE

The adequate management of asymptomatic osteoporotic vertebral burst fractures (OVBFs) was still controversial. Percutaneous vertebroplasty (PVP) could achieve quick recovery with minor trauma, but there were certain safety problems by traditional bone cement injection method. Thus, the aim of this study was to assess the efficacy of lateral-opening injection tool used in PVP treating patients with asymptomatic OVBFs.

METHODS

This was a retrospective study of OVBFs treated in our institute from March 2016 to March 2020. A total of 66 patients (mean age 72.10 ± 7.98 years, with 21 men and 45 women) who were diagnosed with acute asymptomatic OVBFs with mild spinal canal compromise were treated with PVP by using a lateral-opening injection tool. Two puncture needles were simultaneously placed transpedicularly in the fractured vertebra, and the inner core was removed, and the lateral-opening injection tool was inserted. The adjustment of lateral hole was to improve the distribution height of bone cement and avoid the entry of bone cement into the posterior wall of vertebral body. Related clinical outcomes and images were assessed, including back pain (visual analog scale [VAS]), vertebral height ratio (fractured vertebral height/average adjacent nonfractured vertebral height), kyphosis Cobb angle, union of the fractured vertebral posterior wall, distribution of bone cement, surgical data, and complications.

RESULTS

The average follow-up time of all cases was 21.23 ± 9.35 months. The mean amount of bone cement was 3.28 ± 0.35 ml in the vertebrae and the mean operative time was 34.02 ± 5.23 min. There were 60 cases of bone cement that contacted the upper and lower endplates on at least one side. There was no cement leakage into the spinal canal or fracture displacement of the posterior wall of the vertebral body in all cases. The VAS scores were 3.78 ± 0.42 at 1 day postoperatively and 0.53 ± 0.40 at the last follow-up, significantly lower than 8.40 ± 0.48 preoperatively (p < 0.05). The average height ratio of anterior, middle, and posterior vertebral body after operation increased compared with that pre-operation (p < 0.05), and the postoperative kyphosis angle decreased (p < 0.05). At 6 months follow-up, there was no significant height loss of the vertebral body. Computed tomography examination 3 months postoperatively showed that the fracture of posterior vertebral wall healed well in all cases. There were seven cases of bone cement leakage without clinical symptoms and two adjacent vertebral fractures caused by falling. There were no cases of deep vein embolism, lower limb muscle atrophy, pneumonia, decubitus.

CONCLUSION

The lateral opening tool can be safely and effectively used in the PVP treatment on asymptomatic OVBFs with mild spinal canal compromise.

Different Associated Aspects That Influence Complication Rates on Clinical PKP Surgery Using Smart Medical Big Data

Osteoporotic vertebral compression fractures are on the rise in modern society due to the aging population, and this often results in painful symptoms and kyphotic abnormalities in patients. Bone cement was injected into the vertebral body to reinforce the vertebral body and restore most of the damaged vertebrae's natural height. Percutaneous kyphoplasty is the name given to this type of procedure (PKP). Bone cement leakage has been linked to several problems, according to the research. Neurological problems might arise if bone cement leaks into the spinal canal or the nerve root canal during surgery. As a result, PKP surgeons must now deal with the issue of reducing bone cement leakage. Using smart medical big data, this paper examines a sample of PKP operations and then examines different associated aspects that influence complication rates in order to better advice clinical PKP surgery use. There were 172 vertebral bodies in total in 72 patients receiving PKP surgery at a Chinese hospital that were examined by smart medical big data for vertebral degeneration and fusion. Bone cement leakage and variations in preoperative average anterior vertebral column height, preoperative Cobb angle, and the volume of injected bone cement were considered when dividing the patients into leakage and nonleakage groups; then, we figure out what is causing the bone cement to leak. Five patients experienced lung-related problems out of the 18 vertebral bodies with bone cement leaking that were selected for study. That leakage rate was 10.5%. The differences between the two groups in terms of vertebral compression and bone cement injection were statistically significant based on a single-factor analysis. Bone cement leakage in PKP surgery has been linked to the amount of bone cement injected and whether the vertebral body's peripheral wall was injured, according to multivariate analysis. Lung-related problems are more common in patients with a prior history of illness. Osteoporotic vertebral compression fractures can be successfully treated with percutaneous kyphoplasty. An important risk factor for bone cement extravasation in PKP surgery is the amount of bone cement injected, as well as its viscosity and whether damage to the vertebral body's peripheral wall has occurred.

Finite Element Analysis of Unilateral versus Bipedicular Bone-Filling Mesh Container for the Management of Osteoporotic Compression Fractures

The effect of unilateral and bilateral bone-filling mesh containers (BFC) on osteoporotic vertebral compression fracture (OVCF) was analyzed by the finite element method. The CT scan data of the T12-L2 vertebral body were obtained from a healthy female volunteer with no history of lumbar spine injury or obvious abnormality of vertebral body morphology. The normal finite element model of the T12-L2 vertebral body and the finite element model of osteoporosis were established, and the models were validated. The L1 in the normal model of the vertebral body was used to simulate the vertebral compression fracture, after which the unilateral and bilateral BFC were simulated to establish models representing the two surgical approaches. We analyzed changes in the deformation and von Mises stress in vertebral bodies and intervertebral discs in the two models under seven working conditions (axial direction, anteflexion, rear protraction, left-side bending, right-side bending, left rotation, and right rotation) and found that the unilateral and bilateral approaches are biomechanically comparable, with no statistical difference between the two overall models.

Vesselplasty versus vertebroplasty in the treatment of osteoporotic vertebral compression fractures with posterior wall rupture

OBJECTIVE

This study was performed to compare the effectiveness and safety of vesselplasty versus vertebroplasty in the treatment of osteoporotic compression fractures with posterior wall rupture.

METHODS

Patients who underwent treatment of a single osteoporotic vertebral compression fracture with posterior wall rupture from January 2016 to February 2020 were retrospectively reviewed. They were divided into a vesselplasty group (n = 17) and a vertebroplasty group (n = 43). Pain relief, radiographic outcomes, and bone cement leakage were compared between the two groups.

RESULTS

There were no significant differences in the operation time, postoperative pain relief, vertebral compression recovery, or local Cobb angle improvement between the two groups. However, the overall bone cement leakage rate (29.4% vs. 67.4%) and spinal canal leakage rate (0.0% vs. 30.2%) were significantly lower in the vesselplasty group than vertebroplasty group.

CONCLUSIONS

Vesselplasty offers similar pain relief and vertebral compression recovery but lower spinal canal leakage compared with vertebroplasty. Vesselplasty is thus a better option than vertebroplasty for patients with osteoporotic compression fractures with posterior wall rupture.

Tough and injectable fiber reinforced calcium phosphate cement as an alternative to polymethylmethacrylate cement for vertebral augmentation: a biomechanical study

Vertebral compression fractures (VCFs) are a very common problem among the elderly, which ultimately result in severe pain and a drastically reduced quality of life. An effective treatment for VCFs is the minimally invasive augmentation of the damaged vertebrae through vertebroplasty and/or kyphoplasty. These surgical procedures treat the affected vertebrae by injection of poly(methyl methacrylate) cement (PMMA) into the vertebral body. However, clinical use of PMMA cement is associated with major drawbacks. Bioceramic cements such as injectable calcium phosphate cements (CPC) exhibit a superior osteocompatibility over PMMA cements, but are too brittle for load-bearing applications. Here, we evaluated the handling and mechanical properties of a recently developed CPC formulation containing both poly(vinyl alcohol) (PVA) fibers and carboxymethyl cellulose (CMC) as an alternative to PMMA cement for vertebro- and kyphoplasty. Our results demonstrate that the addition of CMC rendered fiber-reinforced CPC injectable without negatively affecting its mechanical properties. Further, an ex vivo mechanical analysis clearly showed that extravasation of PVA fiber-reinforced CPC with CMC into trabecular bone was limited as compared to PMMA. Finally, we observed that the ex vivo biomechanical performance of vertebrae treated with CMC and PVA fibers was similar to PMMA-treated vertebrae. The obtained data suggests that PVA fiber-reinforced CPCs with CMC possesses adequate handling, mechanical and structural characteristics for vertebro- and kyphoplasty procedures. These data pave the way for future preclinical studies on the feasibility of treating vertebral compression fractures using PVA fiber-reinforced CPC with CMC.

Vesselplasty using the Mesh-Hold™ bone-filling container for the treatment of pathological vertebral fractures due to osteolytic metastases: A retrospective study

PURPOSE

To evaluate the clinical benefits and complications of vesselplasty using the Mesh-Hold™ bone-filling container in the treatment of vertebral osteolytic fractures.

METHODS

This was a retrospective study of patients with vertebral osteolytic pathological fractures treated by vesselplasty at Sichuan Cancer Hospital between 09/2014 and 01/2018. VAS¹ (Visual analog scale) scores and ODI² (Oswestry disability index) were recorded routinely 1 day preoperative, at 1 day, 1 month, 3 months, 6 months, and 1 year postoperation, and at the last follow-up. V1³ (The of bone cement injection volume) and V2⁴ (vertebral body osteolytic volume) were evaluated, and the R⁵ (ratio) of bone cement filling was obtained according to the V1/V2.

RESULTS

Sixty-three patients were included (105 segments with osteolytic fractures). The amount of bone cement for each vertebra was 2.4-5.2 ml (3.1 ± 0.7 ml). The ratio (R) of bone cement filling was not related to pain relief or functional recovery (all P > 0.05).The VAS scores and ODI at different time points after surgery were decreased compared with before surgery (all P < 0.05). The bone cement leakage rate was 16.2 % (17/105). The follow-up was 4-30 months (mean of 13 ± 6 months). Thirty patients had died by the last follow-up, all from their cancer.

CONCLUSIONS

The Mesh-Hold™ bone-filling container in the treatment of vertebral fractures induced by osteolytic metastases could reduce pain, improve function, and reduce the bone cement leakage rate in the process of vesselplasty.

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

BACKGROUND CONTEXT

Polymethylmethacrylate (PMMA) is the most commonly used filling material when performing percutaneous kyphoplasty (PKP) for the treatment of osteoporotic vertebral compression fractures. However, there are some inherent and unavoidable drawbacks with the clinical use of PMMA. PMMA bone cement tends to leak during injection, which can lead to injury of the spinal nerves and spinal cord. Moreover, the mechanical strength of PMMA-augmented vertebral bodies is extraordinary and this high level of mechanical strength might predispose to adjacent vertebral fractures. A novel biodegradable calcium phosphate-based nanocomposite (CPN) for PKP augmentation has recently been developed to potentially avoid these issues.

PURPOSE

By comparison with PMMA, the leakage characteristics, biomechanical properties, and dispersion of CPN were evaluated when used for PKP.

STUDY DESIGN

Biomechanical evaluation and studies on the dispersion and anti-leakage properties of CPN and PMMA cements were performed and compared using cadaveric vertebral fracture model, sheep vertebral fracture model, and simulated rigid foam model.

METHODS

Sheep vertebral bodies were decalcified by ethylenediaminetetraacetic acid disodium salt (EDTA-Na₂) to simulate osteoporosis in vitro. After compression to create wedge-shaped fractures using a self-designed fracture creation tool, human cadaveric vertebrae and decalcified sheep vertebrae were augmented by PKP. In addition, three L5 vertebral bodies from human cadavers were used in a contrast vertebroplasty (VP) augmentation experiment. Occurrence of cement leakage was observed and compared between CPN and PMMA during the process of vertebral augmentation. Open-cell rigid foam model (Sawbones#1522-507) was used to create a simulated leakage model for the evaluation of the leakage characteristics of CPN and PMMA with different viscosities. The augmentation effects of CPN and PMMA were evaluated in human cadaveric and decalcified sheep vertebral models and then compared to the results from solid rigid foam model (Sawbones#1522-23). The dispersion abilities of CPN and PMMA were evaluated via three methods as follows. The dispersion volume and dispersion ratio were calculated by three-dimensional reconstruction using human vertebral body CT scans; the ratio of cement area to injection volume was calculated from three-dimensional sections of micro-CT scans of a sheep vertebra; and the micro-CT images of cement dispersion in open-cell rigid foam model (Sawbones#1522-507) were compared between CPN and PMMA. This study was funded by the National Natural Science Foundation of China (No. 81622032, 190,000 dollars and No. 51672184, 90,600 dollars), Principal Project of Natural Science Research of Jiangsu Higher Education Institutions (No. 17KJA180011, 22,000 dollars), and Jiangsu Innovation and Entrepreneurship Program (146,000 dollars).

RESULTS

There was no significant difference in vertebral height between CPN and PMMA during PKP augmentation and both cements restored the vertebral height after augmentation. In PKP augmentation experiment, posterior wall cement leakage occurred in 75% of human vertebrae augmented with PMMA; however, no leakage occurred in human vertebrae augmented with CPN. Anterior leakage occurred in all vertebrae augmented by PMMA, while in only 75% of vertebra augmented by CPN. Furthermore, CPN and PMMA had completely different leakage patterns in the simulated rigid foam model whether administered at the same injection speed or under the same injection force, suggesting that CPN has anti-leakage characteristics. The augmentation in human cadaveric vertebrae was lower with CPN compared to PMMA (1,668±816 N vs. 2,212±813 N, p=.459, respectively), but this difference was not significant. The augmentation force in sheep vertebral bodies reached 1,393±433 N when augmented with PMMA, but 1,108±284 N when augmented with CPN. The dispersion of CPN was better, and the dispersion volume and ratio were greater, with CPN than with PMMA. Imaging of the open-cell rigid foam model showed completely different dispersion modes for CPN and PMMA. After injection, the PMMA cement formed a contracted clump in the open-cell rigid foam model. However, the CPN cement extended many antennae outward, appearing to spread to the surrounding area. The surface areas of the CPN cement blocks with different liquid-to-solid ratios were significantly larger than the surface area of the PMMA cement in the open-cell rigid foam model (p<.05).

CONCLUSIONS

CPN has anti-leakage properties, which might be related to its high viscosity and viscoplasticity. CPN had a slightly lower augmentation force than PMMA when used in cadaveric vertebrae, decalcified sheep vertebrae, and in the standard rigid foam model. However, CPN diffused more easily into cancellous bone than did PMMA and encapsulated bone tissue during the dispersion process. The excellent dispersion of CPN generated better interdigitation with cancellous bone, which may be why the augmentation effect of CPN is similar to that of PMMA.

CLINICAL SIGNIFICANCE

Biodegradable CPN is a potential alternative to PMMA cement in PKP surgery, in which CPN is likely to reduce the cement leakage during the surgery and avoid the post-surgery complications caused by excessive strengths and nondegradability of PMMA cement.

Augmentation of a Locking Plate System Using Bioactive Bone Cement-Experiment in a Proximal Humeral Fracture Model

Introduction:

The purpose of this study was to test whether local filling of a novel strontium-containing hydroxyapatite (Sr-HA) bone cement can augment the fixation of a locking plate system in a cadaveric proximal humeral facture model.

Materials and Methods:

Twelve pairs of formalin-treated cadaveric humeri were used. One side in each pair was for cemented group, while the other side was for the control group. The bone mineral density (BMD) of the samples was tested. A 3-part facture model was created and then reduced and fixed by a locking plate system. In the cemented group, the most proximal 4 screw holes were filled with 0.5 mL bone cement. In the control group, the screw holes were not filled by cement. Locking screws were inserted in a standard manner before the cement hardened. X-ray was taken before all the specimens being subjected to mechanical study, in which 6 pairs were used for axial loading (varus bending) test, while other 6 pairs were used for axial rotational test.

Results:

There is no difference in BMD between the cemented side and the control side. The X-ray shows that the implant is in position. Cement filling was noted in the most proximal 4 screws in the cemented group. Better mechanical outcome was seen in the cemented groups, in terms of less maximal displacement per cycle and higher failure point and stiffness in varus bending test. However, no difference was found between the cemented group and the control group in the axial rotation test.

Discussion:

In similarity with the previous studies, our results showed better mechanical results in the cemented group. However, due to the limitations (e.g. sample size, fracture model, testing protocol, etc), we still cannot directly extrapolate current mechanical results to clinical practice at the present moment. Furthermore, it is still unknown whether better primary outcome may lead to better long-term results, even though the local release of strontium may enhance the local bone formation.

Conclusion:

The local filling of Sr-HA bone cement augments the fixation of the locking plate system in current proximal humeral fracture model.

Review of Percutaneous Kyphoplasty in China

STUDY DESIGN

Review article.

OBJECTIVE

The article mainly reviewed the development and current situation of percutaneous kyphoplasty (PKP) in China, aiming to introduce native efforts and progress for PKP procedure on the exploring road.

SUMMARY OF BACKGROUND DATA

Since PKP was first reported in China in 2002, Chinese orthopedic researchers have performed lots of clinical applications and studies on the treatment of osteoporotic vertebral compression fracture, spinal metastatic tumor, hemangioma, myeloma, vertebral nonunion, and so on.

METHODS

We reviewed the papers on PKP published by native researchers in English and Chinese via Pubmed, EMBASE, the Scopus database, and a series of Chinese databases including Wanfang Data, China National Knowledge Infrastructure (CNKI), and the China Science and Technology Journal Database. The large sample capacity researches, convictive systematic analysis, and overviews were mainly elected as convictive evidence to describe the overall situation of clinical outcomes, complications, and the various technical aspects used to improve conventional surgical management and clinical applications of PKP in China.

RESULTS

Until October 2015, 211 articles in English and 2352 studies in Chinese about PKP were reported by 1443 Chinese institutions from 22 provinces around China. More than 50976 patients reported through published articles have received the treatment of PKP. With the technique gradually improved, including puncture, bone cement infusion, vertebral expander instruments, diagnosis, and treatment of special type of vertebral fractures, PKP is performed with the better efficacy and less complication.

CONCLUSION

With the progression of minimally invasive spinal surgery around the world, PKP in China has been performed with a trend towards a rapid, safe, and effective treatment. Digital, real-time and artificial intelligence are the directions of future development of PKP.

LEVEL OF EVIDENCE

4.

Electrospun Nanofibrous P(DLLA-CL) Balloons as Calcium Phosphate Cement Filled Containers for Bone Repair: in Vitro and in Vivo Studies

The spinal surgeon community has expressed significant interest in applying calcium phosphate cement (CPC) for the treatment of vertebral compression fractures (VCFs) and minimizing its disadvantages, such as its water-induced collapsibility and poor mechanical properties, limiting its clinical use. In this work, novel biodegradable electrospun nanofibrous poly(d,l-lactic acid-ϵ-caprolactone) balloons (ENPBs) were prepared, and the separation, pressure, degradation, and new bone formation behaviors of the ENPBs when used as CPC-filled containers in vitro and in vivo were systematically analyzed and compared. CPC could be separated from surrounding bone tissues by ENPBs in vitro and in vivo. ENPB-CPCs (ENPBs serving as CPC-filled containers) exerted pressure on the surrounding bone microenvironment, which was enough to crush trabecular bone. Compared with the CPC implantation, ENPB-CPCs delayed the degradation of CPC (i.e., its water-induced collapsilibity). Finally, possible mechanisms behind the in vivo effects caused by ENPB-CPCs implanted into rabbit thighbones and pig vertebrae were proposed. This work suggests that ENPBs can be potentially applied as CPC-filled containers in vivo and provides an experimental basis for the clinical application of ENPBs for the treatment of VCFs. In addition, this work will be of benefit to the development of polymer-based medical implants in the future.

Nanotechnology for treating osteoporotic vertebral fractures

Osteoporosis is a serious public health problem affecting hundreds of millions of aged people worldwide, with severe consequences including vertebral fractures that are associated with significant morbidity and mortality. To augment or treat osteoporotic vertebral fractures, a number of surgical approaches including minimally invasive vertebroplasty and kyphoplasty have been developed. However, these approaches face problems and difficulties with efficacy and long-term stability. Recent advances and progress in nanotechnology are opening up new opportunities to improve the surgical procedures for treating osteoporotic vertebral fractures. This article reviews the improvements enabled by new nanomaterials and focuses on new injectable biomaterials like bone cements and surgical instruments for treating vertebral fractures. This article also provides an introduction to osteoporotic vertebral fractures and current clinical treatments, along with the rationale and efficacy of utilizing nanomaterials to modify and improve biomaterials or instruments. In addition, perspectives on future trends with injectable bone cements and surgical instruments enhanced by nanotechnology are provided.

Balloon kyphoplasty versus KIVA vertebral augmentation--comparison of 2 techniques for osteoporotic vertebral body fractures: a prospective randomized study

STUDY DESIGN

Prospective, parallel-group, controlled comparative randomized study.

OBJECTIVE

This study compares the efficacy in sagittal vertebral height and wedge deformity restoration, polymethylmethacrylate cement leakage safety, and functional outcome of balloon kyphoplasty (BK) versus KIVA (a novel vertebral augmentation technique) implant for the augmentation of fresh osteoporotic vertebral body fractures.

SUMMARY OF BACKGROUND DATA

Minimally invasive vertebral augmentation procedures have been widely used to treat vertebral compression fractures caused by osteoporosis. The results of these trials are encouraging in augmenting the vertebra and reducing the wedge deformity. However, after BK, polymethylmethacrylate leakage remains common after A3.1 AO type fractures, with a frequency per vertebra into the epidural space up to 9.8% but less common (0.03%-5.6%) in A1.1 AO type fracture. KIVA is a novel percutaneous uniportal vertebral augmentation device that is designed to restore the vertebral body and reduce polymethylmethacrylate leakage.

METHODS

From a total 190 patients with osteoporotic fractures who were initially enrolled in this prospective randomized study, 10 patients were excluded (5 met exclusion criteria, 5 with evidence of metastasis). This study examined 82 patients (69 ± 11 yr) with 133 fractures who received KIVA and 86 patients (72 ± 9 yr) with 122 fractures that were reinforced with BK. Anterior (anterior vertebral body height ratio [AVBHr]), midline (midline vertebral body height ratio [MVBHr]), and posterior (posterior vertebral body height ratio [PVBHr]) vertebral body height ratio and Gardner segmental vertebral wedge deformity were measured preoperatively to postoperatively. New fractures were recorded at the final observation. The baseline anthropometric and roentgenographic parameters did not differ between the 2 groups. Any cement leakage was examined on plain roentgenograms and computed tomographic scan. All patients were followed for an average of 14 months (range, 13-15 mo) postoperatively. RESULTS.: At the final observation, both KIVA and BK restored significantly AVBHr, PVBHr, and MVBHr. However, only KIVA device reduced significantly the Gardner angle (P = 0.002). Residual kyphosis of more than 5° was measured significantly more (P < 0.001) in the BK than in KIVA spines. KIVA showed significantly lower (3%, χ2, P ≤ 0.05) leakage) [corrected] (paravertebral, intradiscal) rate per vertebra than BK (0.098%) in which because of intracanal leakage 2 patients developed acute paraplegia and were reoperated in emergency. New fracture rate was similar in both groups. Back pain scores (visual analogue scale), 36-Item Short Form Health Survey (Physical Function and Mental Health domains), and Oswestry Disability Index scores improved significantly in the patients of both groups.

CONCLUSION

Both KIVA and BK restored in short-term similarly vertebral body height, but only KIVA restored vertebral body wedge deformity. KIVA was followed by significantly lower and harmless always extracanal leakage rate than BK. Longer observation is needed to show whether these radiological changes have any functional impact.

Novel biodegradable electrospun nanofibrous P(DLLA-CL) balloons for the treatment of vertebral compression fractures

Significant interest has been expressed by the spinal surgeon community for the use of calcium phosphate cement (CPC) in the treatment of vertebral compression fractures (VCFs), but the water-induced collapsibility and poor mechanical properties limit its clinical use. Here we fabricated novel electrospun nanofibrous P(DLLA-CL) balloons (ENPBs) using the nanotechnique of electrospinning. The ENPBs could separate the cements from the surrounding environment, and therefore can prevent the water-induced collapsibility of CPC and eliminate cement leakage. The ENPBs filling with CPC had enough load-bearing ability to restore the height of the fractured vertebral body and had no obvious effects on the initial strength and stiffness of natural bones. Further, the ENPBs had good biodegradability and cell proliferation ability. Calcium can be released from ENPBs filling with CPC. All these results strongly demonstrate ENPBs can be potentially used as CPC filling containers that keep the advantages and eliminate the disadvantages of CPC.

FROM THE CLINICAL EDITOR

Calcium phosphate cement (CPC) is a promising modality in vertebral compression fracture treatment, but its water-induced collapsibility limits clinical applications. This team of investigators fabricated novel nanofibrous balloons using electrospinning, which enabled the separation of CPC from its surrounding environment, and therefore prevented water-induced collapsibility of CPC and eliminated cement leakage while maintaining all the advantages of CPC treatment.

An evaluation of fracture stabilization comparing kyphoplasty and titanium mesh repair techniques for vertebral compression fractures: is bone cement necessary?

STUDY DESIGN

In vitro biomechanical investigation using human cadaveric vertebral bodies.

OBJECTIVE

To evaluate differences in biomechanical stability of vertebral compression fractures (VCFs) repaired using an expandable titanium mesh implant, with and without cement, as compared with standard balloon kyphoplasty.

SUMMARY OF BACKGROUND DATA

Vertebral augmentation, either in the form of vertebroplasty or kyphoplasty, is the treatment of choice for some VCFs. Polymethylmethacrylate, a common bone cement used in this procedure, has been shown to possibly cause injury to neural and vascular structures due to extravasation, embolization, and may be too rigid for an osteoporotic spine. Therefore, suitable alternatives for the treatment of VCFs have been sought.

METHODS

Individual vertebral bodies from 5 human cadaveric spines (from T4 to L5) were stripped of all soft tissues, and compressed at 25% of the intact height using methods previously described. Vertebral bodies were then randomly assigned to the following repair techniques: (1) conventional kyphoplasty, (2) titanium implant with cement, (3) titanium implant without cement. All vertebral bodies were then recompressed at 25% of the repaired height. Yield load, ultimate load, and stiffness were recorded and compared in these groups before and after treatment.

RESULTS

There were no differences in biomechanical data between intact groups, and between repaired groups. In all 3 treatment groups, yield load and ultimate load of repaired vertebrae were similar to that of intact vertebrae. However, the stiffness following repair was found to be statistically less than the stiffness of the intact vertebral body (P < 0.05 for all comparisons).

CONCLUSION

Based on the biomechanical data, the titanium mesh implant with or without cement was similar to polymethylmethacrylate fixation by kyphoplasty in the treatment of VCFs. Avoiding the adverse effects caused by using cement may be the main advantage of the titanium mesh implant and warrants further study.

Feasibility study of using viscoplastic bone cement for vertebroplasty: an in vivo clinical trial and in vitro cadaveric biomechanical examination

STUDY DESIGN

An in vivo clinical trial, and an in vitro cadaveric biomechanical and micromorphologic analysis.

OBJECTIVE

To find the feasibility of using viscoplastic bone cement for vertebroplasty.

SUMMARY OF BACKGROUND DATA

Vertebroplasty involved in bone cement reinforcement of fractured vertebra has shown promising clinical results. The most frequently observed complication of vertebroplasty is the cement leakage during surgery. Many methods were proposed and were successful at reducing the risk of leakage, such as creating a void within vertebra to reduce the injection pressure, increasing the cement viscosity to reduce the cement infiltration, etc. Nevertheless, a more cost-effective and safer surgery method is still the goal for many spine surgeons and researchers.

METHODS

To deliver the viscoplastic bone cement into the vertebra, a unipedicular tract and a void in the vertebra was created using a curette. The viscoplastic bone cement was then delivered into the void piece by piece and tamped for compactness with a blunt end tool. For the in vitro biomechanical test, 7 thoracic vertebrae were used. The intact specimens were compressed to lose 25% of its intact height, and then augmented with viscoplastic bone cement. Postaugmentation CT scanning was taken to examine the cement distribution, leakage path, and cement filling ratio within the vertebra. Postaugmentation compression test was conducted to examine the vertebral strength and stiffness, and then compared with the intact ones. Finally, the vertebrae were cut into slices for micromorphologic analysis.

RESULTS

The 6 in vivo clinical trials were all successfully operated with significant pain relief and showed no leakage during and after the surgery. The in vitro biomechanical test showed the cement augmentation significantly increased the vertebral strength (pre 3164 (229) N vs. post 3905 (484) N, P < 0.003), but tentatively decreased the vertebral stiffness (pre 1074 (74) N/mm vs. post 801 (370) N/mm, P = 0.081). The postaugmentation CT scanning showed the cement was well confined within the vertebra and the cement filling ratio was 21% (ranged from 15% to 29%). The depth that the viscoplastic bone cement infiltrated into the cancellous bone was 3.5 (0.6) mm, which is less than the depth [8.3 (2.2) mm, P < 0.001] of standard viscous bone cement vertebroplasty.

CONCLUSION

Vertebroplasty using viscoplastic bone cement is clinically feasible and can effectively improve the vertebral strength and reduce the cement infiltration depth. The risk of cement leakage can also be decreased by using viscoplastic bone cement.