Percutaneous vertebroplasty: history, technique and current perspectives

Comparison of the efficacy and safety of vertebroplasty with different pedicle approaches for osteoporotic vertebral

OBJECTIVE

To compare the efficacy and safety of vertebroplasty through different pedicle approaches in the treatment of osteoporotic vertebral compression fracture osteoporotic vertebral compression fractures (OVCF) by network meta-analysis.

METHODS

Pubmed, Embase, Cochrane Library, Web of Science. Database for literature retrieval, retrieval time from the establishment of the database to April 2023, the randomized controlled trials of unilateral vertebroplasty (UVP), bilateral vertebroplasty (BVP), unilateral kyphoplasty (UKP), bilateral kyphoplasty (BKP), curved vertebroplasty (CVP) and curved kyphoplasty (CKP) were screened, evaluated and the data were extracted and included in the analysis. STATA 15.0 and ReMan 5.3 were used for data analysis. This study was registered in the National Institute for Health Research (NIHR) with the registration number CRD42023405181.

RESULTS

This study included 16 articles with a total of 1712 patients. The order of visual analogue scale (VAS) improvement from good to bad is CVP > BVP > UVP > CKP > BKP > UKP. The order of kyphotic angles improvement from good to bad is CKP > UKP > UKP > UVP > BVP > CVP. The order of bone cement injection from less to more is UVP > CVP > UKP > CKP > BVP > BKP. The order of bone cement leakage rate from less to more is CKP > CVP > UKP > BKP > UVP > BVP. The order of X-ray exposure time from less to more is CKP > CVP > UVP > BVP > UKP > BKP. The order of operation time from less to more is CVP > UVP > UKP > CKP > BVP > BKP.

CONCLUSION

For patients with kyphotic angles, kyphoplasty has unique advantages in improving kyphotic angles. But generally speaking, curved approach can optimize the distribution of bone cement through unilateral approach to achieve the orthopedic effect of bilateral approach, which is a minimally invasive technique with better curative effect and higher safety in the treatment of OVCF.

A 20-Year Review of Biomechanical Experimental Studies on Spine Implants Used for Percutaneous Surgical Repair of Vertebral Compression Fractures

A vertebral compression fracture (VCF) is an injury to a vertebra of the spine affecting the cortical walls and/or middle cancellous section. The most common risk factor for a VCF is osteoporosis, thus predisposing the elderly and postmenopausal women to this injury. Clinical consequences include loss of vertebral height, kyphotic deformity, altered stance, back pain, reduced mobility, reduced abdominal space, and reduced thoracic space, as well as early mortality. To restore vertebral mechanical stability, overall spine function, and patient quality of life, the original percutaneous surgical intervention has been vertebroplasty, whereby bone cement is injected into the affected vertebra. Because vertebroplasty cannot fully restore vertebral height, newer surgical techniques have been developed, such as kyphoplasty, stents, jacks, coils, and cubes. But, relatively few studies have experimentally assessed the biomechanical performance of these newer procedures. This article reviews over 20 years of scientific literature that has experimentally evaluated the biomechanics of percutaneous VCF repair methods. Specifically, this article describes the basic operating principles of the repair methods, the study protocols used to experimentally assess their biomechanical performance, and the actual biomechanical data measured, as well as giving a number of recommendations for future research directions.

An anatomical feasibility study using CTA reconstruction for modified percutaneous lumbar vertebroplasty

Background

Lumbar vertebroplasty via several different types of extrapedicular approach has been reported with acceptable clinical results yet the anatomical basis for its safety is not fully explored. Injury to the lumbar arteries (LAs) is one of the most important potential complications. However, anatomical research on the course and variability of this structure is lacking. To investigate the anatomical feasibility of percutaneous vertebroplasty for lumbar osteoporotic vertebral compression fractures via a unilateral Extrapedicular approach.

Methods

A total of 300 LAs of 30 patients with non-spinal disorders were retrospectively analyzed by computed tomographic angiography (CTA). The lateral aspect of the vertebral body was divided into 9 zones of approximately equal area. The anatomy and orientation of LAs were analyzed in detail.

Results

LAs were most commonly found in the middle third of the body (zones 4, 5, and 6); the upper 1/3 of the vertebral body had LAs distributed only anteriorly and laterally (zones 1 and 2). No arteries were observed in the postero-superior segment (zone 3). From L1 to L3 an arched pattern predominated. At L4 an inferior oblique pattern (antero-superior to postero-inferior) predominated. Limited CTA visualization at L4 and particularly L5 as well as greater anatomical variation means that there is more uncertainty at these levels.

Conclusion

From L1 to L3, the posterior superior segment (zone 1) of the vertebral body appears to be a safe area with low risk of arterial injury. This has relevance for design of a safe lumbar vertebral extrapedicular approach.

Vertebral Augmentation of Cancer-Related Spinal Compression Fractures: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To compare the magnitude and duration of pain relief with vertebral augmentation to any other therapy for the treatment of cancer-related vertebral compression fractures through meta-analysis of randomized controlled trials.

SUMMARY OF BACKGROUND DATA

Derived from search on PubMed, EMBASE, CINAHL, Scopus, Central, Scopus, and Web of Science databases in May 2020. Studies selected were limited to randomized controlled trials comparing vertebral augmentation, either Balloon Kyphoplasty or Percutaneous Vertebroplasty (PVP) with or without additional therapy to any other intervention or placebo/sham.

METHODS

The methodological quality of each included study was assessed according to the Cochrane Collaboration's domain-based framework. Random effects model, Q test, and I2 statistics were implemented.

RESULTS

Of 180 records identified, 7 were considered relevant, and included 476 participants. The risk of bias was considered "Low" in all studies. In five of the studies, vertebral augmentation alone (either PVP or Balloon Kyphoplasty) comprised one group, while comparative treatments included nonsurgical management, Kiva implantation, PVP and radiofrequency therapy, PVP and chemotherapy, PVP and intrasomatic injection of steroid, and PVP with 125I seeds. Two studies compared PVP with an additional therapy against the standard of care. With regard to changes in pain severity, the effect sizes varied from 0.0 (95% -1.7 to 1.7) to -5.1 (95% -5.3 to -4.9). Most studies demonstrated a positive and statistically significant effect associated with PVP. Four of the seven studies demonstrated a clinically significant effect as well. Other than cement leakage, with an event rate of 0.24 (95% CI 0.11-0.44) or 24% (95% CI 11%-44%), there were no major adverse events consistently observed across multiple studies.

CONCLUSIONS

The included randomized controlled trials demonstrated an overall positive and statistically significant effect of vertebral augmentation surgeries, such as vertebroplasty and kyphoplasty, for the treatment of cancer-related vertebral compression fractures, especially when compared with nonsurgical management, radiofrequency ablation, or chemotherapy alone.Level of Evidence: 1.

Robot-Assisted Bone Cement Injection

In this article, assistance to bone cement injection is studied, with a focus on vertebroplasty, a procedure dedicated to the treatment of vertebral compression fractures. A robotic system that can remotely be operated at pressures up to 140 bar is presented. It improves cement polymerization control, combining a cold passive exchanger that slows down the cement curing in the syringe and an active exchanger that controls the injected cement temperature. The cement remote injection uses a rate control teleoperation strategy with force feedback to help monitoring the cement state. In addition to laboratory assessments, cadaver experiments were performed to illustrate the satisfactory operation of the whole system.

Efficacy of Percutaneous Vertebroplasty in the Treatment of Malignant and Benign Vertebral Fractures: Single-Center Experiences

Percutaneous vertebroplasty (PVP) is a method used for vertebral stabilization and pain treatment. This study was performed to demonstrate the efficacy of PVP in treatment of malignant and benign vertebral compression fractures (VCFs). The study was conducted on 45 cases with a total of 106 VCFs. The mean age of the patients was 62.4 years (37–86 years). The vertebral fractures were classified according to Genant’s Classification. Pain was rated using the visual analog scale (VAS). VAS scores were recorded before and after PVP operations. A total of 58 vertebrae (54.8%) were treated via a bipedicular approach, and 48 vertebrae (45.2%) were treated via a unilateral transpedicular approach with the help of biplane imaging and under anesthesia. L1 vertebra (19.8%) fractures and Grade III fractures (46.3%) were more common. Vertebral collapse was the most common cause of malignancy (53.8%). The mean VAS score was measured to be 8.39 before the VP operations and 2.05 after the VP operations. The VAS score dropped to 2.3 through the unipedicular approach and to 1.84 through the bipedicular approach. The decrease in pain due to VP was statistically significant (p < 0.001). There was no statistically significant difference between the unipedicular and bipedicular approaches in terms of pain relief (p> 0.05). Some patients (18.8%) had complications. PVP is a highly therapeutic method for pain relief in case of pain secondary to malignant or benign vertebral fractures.

Chitosan based bioactive materials in tissue engineering applications-A review

In recent years, there have been increasingly rapid advances of using bioactive materials in tissue engineering applications. Bioactive materials constitute many different structures based upon ceramic, metallic or polymeric materials, and can elicit specific tissue responses. However, most of them are relatively brittle, stiff, and difficult to form into complex shapes. Hence, there has been a growing demand for preparing materials with tailored physical, biological, and mechanical properties, as well as predictable degradation behavior. Chitosan-based materials have been shown to be ideal bioactive materials due to their outstanding properties such as formability into different structures, and fabricability with a wide range of bioactive materials, in addition to their biocompatibility and biodegradability. This review highlights scientific findings concerning the use of innovative chitosan-based bioactive materials in the fields of tissue engineering, with an outlook into their future applications. It also covers latest developments in terms of constituents, fabrication technologies, structural, and bioactive properties of these materials that may represent an effective solution for tissue engineering materials, making them a realistic clinical alternative in the near future.

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

PURPOSE

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.

METHODS

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 3.5 mm diameter anterior cannulated lag screw with a 12 mm 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.

RESULTS

The mean cement volume was lowest for body base filling with 0.47 ± 0.03 ml. The standard body filling corresponds to 0.95 ± 0.15 ml. The largest volume corresponds to 1.62 ± 0.12 ml 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 = 3000 MPa) increased linearly (R2 = 0.98). The lowest stiffness (123.3 ± 5.8 N/mm) was measured in the intact C2 vertebrae. However, the highest stiffness (165.2 ± 5.2 N/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 ± 8.4 N/mm compared with 157.9 ± 6.6 N/mm for the base and body cemented group. This difference was statistically significant (p < 0.0061). The mean initial stiffness for porous cement (E = 500 MPa) remains constant. Therefore, there is no difference between cemented and non-cemented junction. This difference was not statistically significant (p < 0.18).

CONCLUSION

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 0.7-1.2 ml of cement. These slides can be retrieved under Electronic Supplementary Material.

Surface degradation-enabled osseointegrative, angiogenic and antiinfective properties of magnesium-modified acrylic bone cement

Objective

This work focuses on tackling the inadequate bone/implant interface strength of acrylic bone cements, which is a formidable problem diminishing their clinical performance, especially in percutaneous kyphoplasty surgery.

Methods

A new strategy of incorporating magnesium particles into clinically used poly(methylmethacrylate) (PMMA) bone cement to prepare a surface-degradable bone cement (SdBC) is proposed and validated both in vitro and in vivo.

Results

This surface degradation characteristic enables osseointegrative, angiogenic and antiinfective properties. SdBC showed fast surface degradation and formed porous surfaces as designed, while the desirable high compressive strengths (≥70 MPa) of the cement were preserved. Besides, the SdBC with proper Mg content promoted osteoblast adhesion, spreading, proliferation and endothelial cell angiogenesis capacity compared with PMMA. Also, SdBC demonstrated clear inhibitory effect on Staphylococcus aureus and Escherichia coli. In vivo evaluation on SdBC by the rat femur defect model showed that the bone/implant interface strength was significantly enhanced in SdBC (push-out force of 11.8 ± 1.5 N for SdBC vs 7.0 ± 2.3N for PMMA), suggesting significantly improved osseointegration and bone growth induced by the surface degradation of the cement. The injectability, setting times and compressive strengths of SdBC with proper content of Mg particles (2.8 wt% and 5.4 wt%) were comparable with those of the clinical acrylic bone cement, while the heat release during polymerization was reduced (maximum temperature 78 ± 1 °C for PMMA vs 73.3 ± 1.5 °C for SdBC).

Conclusions

This work validates a new concept of designing bioactive bone/implant interface in PMMA bone cement. And this surface-degradable bone cement possesses great potential for minimally invasive orthopaedic surgeries such as percutaneous kyphoplasty.

The translational potential of this article

This work reports PMMA/Mg surface-degradable acrylic bone cements that possess enhanced osseointegrative, angiogenic and antiinfective properties that are lacking in the clinically used acrylic bone cements. This new kind of bone cements could improve the treatment outcome of many orthopaedic surgeries such as percutaneous kyphoplasty and arthroplasty.

Fabrication of biocomposite scaffolds made with modified hydroxyapatite inclusion of chitosan-grafted-poly(methyl methacrylate) for bone tissue engineering

In the present study, composite scaffolds of chitosan-graft-poly(methyl methacrylate) (Chi-g-PMMA) and mineral ions-loaded hydroxyapatite (mHA) (obtained by the hydrothermal treatment of hydroxyapatite (HA) in a simulated body fluid (SBF) solution (mHA@Chi-g-PMMA)) were prepared by the blending method. The physical properties, bioactivity, biological properties and their capabilities for sustained drug and protein release were studied. Physicochemical analysis showed a successful incorporation of the mineral ions in the HA particles and a good distribution of the mHA within the Chi-g-PMMA polymer matrix. The compressive strength and the Young's modulus were 15.760 ± 0.718 and 658.452 ± 17.020 MPa, respectively. In bioactivity studies, more apatite formation on the surface were seen after immersion in the SBF solution. In vitro growth experiments using UMR-106 osteoblast-like cells on the mHA@Chi-g-PMMA scaffold case showed that the attachment, viability and proliferation of the cells on the scaffolds had improved after 7 d of immersion. The in vitro release of two compounds (the cancer drug, doxorubicin (DOX)) and bovine serum albumin (BSA)), which had been attached to separate mHA@Chi-g-PMMA scaffolds, were studied to determine their suitability as drug delivery vehicles. It was found that the sustained release of DOX was 73.95% and of BSA was 57.27% after 25 h of incubation. These experimental results demonstrated that the mHA@Chi-g-PMMA composite can be utilized as a scaffold for bone cells ingrowth and also be used for drug delivery during the bone repairing.

Percutaneous vertebroplasty for osteoporotic vertebral compression fracture

BACKGROUND

Percutaneous vertebroplasty remains widely used to treat osteoporotic vertebral fractures although our 2015 Cochrane review did not support its role in routine practice.

OBJECTIVES

To update the available evidence of the benefits and harms of vertebroplasty for treatment of osteoporotic vertebral fractures.

SEARCH METHODS

We updated the search of CENTRAL, MEDLINE and Embase and trial registries to 15 November 2017.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials (RCTs) of adults with painful osteoporotic vertebral fractures, comparing vertebroplasty with placebo (sham), usual care, or another intervention. As it is least prone to bias, vertebroplasty compared with placebo was the primary comparison. Major outcomes were mean overall pain, disability, disease-specific and overall health-related quality of life, patient-reported treatment success, new symptomatic vertebral fractures and number of other serious adverse events.

DATA COLLECTION AND ANALYSIS

We used standard methodologic procedures expected by Cochrane.

MAIN RESULTS

Twenty-one trials were included: five compared vertebroplasty with placebo (541 randomised participants), eight with usual care (1136 randomised participants), seven with kyphoplasty (968 randomised participants) and one compared vertebroplasty with facet joint glucocorticoid injection (217 randomised participants). Trial size varied from 46 to 404 participants, most participants were female, mean age ranged between 62.6 and 81 years, and mean symptom duration varied from a week to more than six months.Four placebo-controlled trials were at low risk of bias and one was possibly susceptible to performance and detection bias. Other trials were at risk of bias for several criteria, most notably due to lack of participant and personnel blinding.Compared with placebo, high- to moderate-quality evidence from five trials indicates that vertebroplasty provides no clinically important benefits with respect to pain, disability, disease-specific or overall quality of life or treatment success at one month. Evidence for quality of life and treatment success was downgraded due to possible imprecision. Evidence was not downgraded for potential publication bias as only one placebo-controlled trial remains unreported. Mean pain (on a scale zero to 10, higher scores indicate more pain) was five points with placebo and 0.7 points better (0.3 better to 1.2 better) with vertebroplasty, an absolute pain reduction of 7% (3% better to 12% better, minimal clinical important difference is 15%) and relative reduction of 10% (4% better to 17% better) (five trials, 535 participants). Mean disability measured by the Roland-Morris Disability Questionnaire (scale range zero to 23, higher scores indicate worse disability) was 14.2 points in the placebo group and 1.5 points better (0.4 better to 2.6 better) in the vertebroplasty group, absolute improvement 7% (2% to 11% better), relative improvement 9% better (2% to 15% better) (four trials, 472 participants).Disease-specific quality of life measured by the Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO) (scale zero to 100, higher scores indicating worse quality of life) was 62 points in the placebo group and 2.3 points better (1.4 points worse to 6.7 points better), an absolute imrovement of 2% (1% worse to 6% better); relative improvement 4% better (2% worse to 10% better) (three trials, 351 participants). Overall quality of life (European Quality of Life (EQ5D), zero = death to 1 = perfect health, higher scores indicate greater quality of life) was 0.38 points in the placebo group and 0.05 points better (0.01 better to 0.09 better) in the vertebroplasty group, absolute improvement: 5% (1% to 9% better), relative improvement: 18% (4% to 32% better) (three trials, 285 participants). In one trial (78 participants), 9/40 (or 225 per 1000) people perceived that treatment was successful in the placebo group compared with 12/38 (or 315 per 1000; 95% CI 150 to 664) in the vertebroplasty group, RR 1.40 (95% CI 0.67 to 2.95), absolute difference: 9% more reported success (11% fewer to 29% more); relative change: 40% more reported success (33% fewer to 195% more).Low-quality evidence (downgraded due to imprecision and potential for bias from the usual-care controlled trials) indicates uncertainty around the risk estimates of harms with vertebroplasty. The incidence of new symptomatic vertebral fractures (from six trials) was 48/418 (95 per 1000; range 34 to 264)) in the vertebroplasty group compared with 31/422 (73 per 1000) in the control group; RR 1.29 (95% CI 0.46 to 3.62)). The incidence of other serious adverse events (five trials) was 16/408 (34 per 1000, range 18 to 62) in the vertebroplasty group compared with 23/413 (56 per 1000) in the control group; RR 0.61 (95% CI 0.33 to 1.10). Notably, serious adverse events reported with vertebroplasty included osteomyelitis, cord compression, thecal sac injury and respiratory failure.Our subgroup analyses indicate that the effects did not differ according to duration of pain (acute versus subacute). Including data from the eight trials that compared vertebroplasty with usual care in a sensitivity analyses altered the primary results, with all combined analyses displaying considerable heterogeneity.

AUTHORS' CONCLUSIONS

We found high- to moderate-quality evidence that vertebroplasty has no important benefit in terms of pain, disability, quality of life or treatment success in the treatment of acute or subacute osteoporotic vertebral fractures in routine practice when compared with a sham procedure. Results were consistent across the studies irrespective of the average duration of pain.Sensitivity analyses confirmed that open trials comparing vertebroplasty with usual care are likely to have overestimated any benefit of vertebroplasty. Correcting for these biases would likely drive any benefits observed with vertebroplasty towards the null, in keeping with findings from the placebo-controlled trials.Numerous serious adverse events have been observed following vertebroplasty. However due to the small number of events, we cannot be certain about whether or not vertebroplasty results in a clinically important increased risk of new symptomatic vertebral fractures and/or other serious adverse events. Patients should be informed about both the high- to moderate-quality evidence that shows no important benefit of vertebroplasty and its potential for harm.

Cadaveric device-injected very high-viscosity cement during vertebroplasty

Introduction:

Cement extravasation during vertebroplasty (VP) is the most commonly reported complication. Cement viscosity is considered the single most important predictor of the risk of extravasation. Certainly, injecting high-viscosity cement (HVC) is difficult to utilize in real practice. We invented a new device capable of injecting high-viscosity with ease and at a distance to avoid radiation. The aim of this study is to confirm the efficacy and safety of the new device on cadaveric vertebrae.

Methodology:

A 126 osteoporotic vertebral bodies were harvested from cadavers. Eighty vertebrae were included in the study. Computer-randomization software was used to allocate specimens over two main groups, Conventional VP and New Device. Both groups were further subdivided into two subgroups; high-viscosity and low-viscosity. A custom device was used on each vertebra to induce a compression fracture.

Results:

Injecting HVC was associated with a lower leakage volume compared with low-viscosity cement. HVC was associated with no leakage into the spinal canal. It was also associated with a low incidence of vascular extravasation (P < 0.001). The mean volume of cement leakage in the low-viscosity group was 0.23 and 0.15 cc, for the Conventional VP and New Device, respectively. In both groups, the most common site for leakage was the vertebral end plate, which was exhibited more in the low-viscosity group (71.5%) compared with the high-viscosity group (42.5%). The preset target amount of cement to be injected was reached in 99% of the time when injecting HVC with the New Device, compared with 62% using the Conventional VP. In both groups, there was no correlation between the amount of cement injected and the amount of leakage.

Conclusion:

The new device is capable of injecting HVC easily, with a lower incidence of cement leakage. It also minimized the risk of radiation exposure to the surgeon.

The therapeutic effects of percutaneous kyphoplasty on osteoporotic vertebral compression fractures with or without intravertebral cleft

PURPOSE

The purpose of this study was to investigate the clinical effects of percutaneous kyphoplasty (PKP) on osteoporotic vertebral compression fractures (OVCFs) with or without intravertebral cleft (IVC).

METHODS

From 2010 to 2016, 309 OVCFs patients (43 males, 266 females) treated with PKP were included in our study. All patients were divided into no intravertebral cleft (NIVC) group and intravertebral cleft (IVC) group according to pre-operative magnetic resonance imaging. Anterior wall height (AWH), posterior wall height (PWH), and kyphotic angle (KA) of the injured vertebral body were evaluated pre-operatively, post-operatively, and at final follow-up.

RESULTS

All patients were followed up for 12~34 months, with an average of 16.2 months. The incidence of IVC was associated with older age and lower bone mineral density (BMD). The anterior wall, posterior wall, and kyphotic angle of vertebral bodies of patients from both groups were significantly improved immediately after surgery. The visual analogue scale (VAS) and Oswestry Disability Index (ODI) also improved significantly without significant difference between the two groups. At the final follow-up, compared to that immediately after surgery, the anterior wall height decreased and kyphotic angle increased significantly in both groups. Compared to the NIVC group, the kyphotic angle in the IVC group increased more significantly within 1 year after surgery. The volume of bone cement injected in the IVC group was larger and consequent. The IVC group had higher incidence of bone cement leakage than the NIVC group, but there was no statistic difference between two groups.

CONCLUSION

Our results suggested that unilateral PKP was a safe and reliable treatment for OVCFs with IVC. However, the IVC group had higher incidence of bone cement leakage during surgery and more severe KA rebound during the follow-up period. Therefore, to reduce the incidence of bone cement leakage, it is very important to evaluate the pre-operative imaging and inject the cement carefully and repetitiously. When cement leakages are found, injection should be stopped immediately. Longer rehabilitation interventions such as wearing suitable brace, doing exercise to strengthen low-back muscle, and replacing bending with squatting in ordinary living are essential to prevent KA rebound in patients with OVCFs with IVC. However, extended follow-up may be necessary for patients with OVCFs with IVC.

Percutaneous vertebroplasty for osteoporotic vertebral compression fracture

BACKGROUND

Percutaneous vertebroplasty remains widely used to treat osteoporotic vertebral fractures although our 2015 Cochrane review did not support its role in routine practice.

OBJECTIVES

To update the available evidence of the benefits and harms of vertebroplasty for treatment of osteoporotic vertebral fractures.

SEARCH METHODS

We updated the search of CENTRAL, MEDLINE and Embase and trial registries to 15 November 2017.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials (RCTs) of adults with painful osteoporotic vertebral fractures, comparing vertebroplasty with placebo (sham), usual care, or another intervention. As it is least prone to bias, vertebroplasty compared with placebo was the primary comparison. Major outcomes were mean overall pain, disability, disease-specific and overall health-related quality of life, patient-reported treatment success, new symptomatic vertebral fractures and number of other serious adverse events.

DATA COLLECTION AND ANALYSIS

We used standard methodologic procedures expected by Cochrane.

MAIN RESULTS

Twenty-one trials were included: five compared vertebroplasty with placebo (541 randomised participants), eight with usual care (1136 randomised participants), seven with kyphoplasty (968 randomised participants) and one compared vertebroplasty with facet joint glucocorticoid injection (217 randomised participants). Trial size varied from 46 to 404 participants, most participants were female, mean age ranged between 62.6 and 81 years, and mean symptom duration varied from a week to more than six months.Three placebo-controlled trials were at low risk of bias and two were possibly susceptible to performance and detection bias. Other trials were at risk of bias for several criteria, most notably due to lack of participant and personnel blinding.Compared with placebo, high- to moderate-quality evidence from five trials (one with incomplete data reported) indicates that vertebroplasty provides no clinically important benefits with respect to pain, disability, disease-specific or overall quality of life or treatment success at one month. Evidence for quality of life and treatment success was downgraded due to possible imprecision. Evidence was not downgraded for potential publication bias as only one placebo-controlled trial remains unreported. Mean pain (on a scale zero to 10, higher scores indicate more pain) was five points with placebo and 0.6 points better (0.2 better to 1 better) with vertebroplasty, an absolute pain reduction of 6% (2% better to 10% better, minimal clinical important difference is 15%) and relative reduction of 9% (3% better to14% better) (five trials, 535 participants). Mean disability measured by the Roland-Morris Disability Questionnaire (scale range zero to 23, higher scores indicate worse disability) was 14.2 points in the placebo group and 1.7 points better (0.3 better to 3.1 better) in the vertebroplasty group, absolute improvement 7% (1% to 14% better), relative improvement 10% better (3% to 18% better) (three trials, 296 participants).Disease-specific quality of life measured by the Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO) (scale zero to 100, higher scores indicating worse quality of life) was 62 points in the placebo group and 2.75 points (3.53 worse to 9.02 better) in the vertebroplasty group, absolute change: 3% better (4% worse to 9% better), relative change: 5% better (6% worse to 15% better (two trials, 175 participants). Overall quality of life (European Quality of Life (EQ5D), zero = death to 1 = perfect health, higher scores indicate greater quality of life) was 0.38 points in the placebo group and 0.05 points better (0.01 better to 0.09 better) in the vertebroplasty group, absolute improvement: 5% (1% to 9% better), relative improvement: 18% (4% to 32% better) (three trials, 285 participants). In one trial (78 participants), 9/40 (or 225 per 1000) people perceived that treatment was successful in the placebo group compared with 12/38 (or 315 per 1000; 95% CI 150 to 664) in the vertebroplasty group, RR 1.40 (95% CI 0.67 to 2.95), absolute difference: 9% more reported success (11% fewer to 29% more); relative change: 40% more reported success (33% fewer to 195% more).Moderate-quality evidence (low number of events) from seven trials (four placebo, three usual care, 1020 participants), up to 24 months follow-up, indicates we are uncertain whether vertebroplasty increases the risk of new symptomatic vertebral fractures (70/509 (or 130 per 1000; range 60 to 247) observed in the vertebroplasty group compared with 59/511 (120 per 1000) in the control group; RR 1.08 (95% CI 0.62 to 1.87)).Similarly, moderate-quality evidence (low number of events) from five trials (three placebo, two usual care, 821 participants), indicates uncertainty around the risk of other serious adverse events (18/408 or 76 per 1000, range 6 to 156) in the vertebroplasty group compared with 26/413 (or 106 per 1000) in the control group; RR 0.64 (95% CI 0.36 to 1.12). Notably, serious adverse events reported with vertebroplasty included osteomyelitis, cord compression, thecal sac injury and respiratory failure.Our subgroup analyses indicate that the effects did not differ according to duration of pain ≤ 6 weeks versus > 6 weeks. Including data from the eight trials that compared vertebroplasty with usual care in a sensitivity analyses altered the primary results, with all combined analyses displaying considerable heterogeneity.

AUTHORS' CONCLUSIONS

Based upon high- to moderate-quality evidence, our updated review does not support a role for vertebroplasty for treating acute or subacute osteoporotic vertebral fractures in routine practice. We found no demonstrable clinically important benefits compared with placebo (sham procedure) and subgroup analyses indicated that the results did not differ according to duration of pain ≤ 6 weeks versus > 6 weeks.Sensitivity analyses confirmed that open trials comparing vertebroplasty with usual care are likely to have overestimated any benefit of vertebroplasty. Correcting for these biases would likely drive any benefits observed with vertebroplasty towards the null, in keeping with findings from the placebo-controlled trials.Numerous serious adverse events have been observed following vertebroplasty. However due to the small number of events, we cannot be certain about whether or not vertebroplasty results in a clinically important increased risk of new symptomatic vertebral fractures and/or other serious adverse events. Patients should be informed about both the high- to moderate-quality evidence that shows no important benefit of vertebroplasty and its potential for harm.

Treating osteoporotic vertebral compression fractures with intraosseous vacuum phenomena using high-viscosity bone cement via bilateral percutaneous vertebroplasty

Osteoporotic vertebral compression fractures with intraosseous vacuum phenomena could cause persistent back pains in patients, even after receiving conservative treatment. The aim of this study was to evaluate the efficacy of using high-viscosity bone cement via bilateral percutaneous vertebroplasty in treating patients who have osteoporotic vertebral compression fractures with intraosseous vacuum phenomena.Twenty osteoporotic vertebral compression fracture patients with intraosseous vacuum phenomena, who received at least 2 months of conservative treatment, were further treated by injecting high-viscosity bone cement via bilateral percutaneous vertebroplasty due to failure of conservative treatment. Treatment efficacy was evaluated by determining the anterior vertebral compression rates, visual analog scale (VAS) scores, and Oswestry disability index (ODI) scores at 1 day before the operation, on the first day of postoperation, at 1-month postoperation, and at 1-year postoperation.Three of 20 patients had asymptomatic bone cement leakage when treated via percutaneous vertebroplasty; however, no serious complications related to these treatments were observed during the 1-year follow-up period. A statistically significant improvement on the anterior vertebral compression rates, VAS scores, and ODI scores were achieved after percutaneous vertebroplasty. However, differences in the anterior vertebral compression rate, VAS score, and ODI score in the different time points during the 1-year follow-up period was not statistically significant (P > 0.05).Within the limitations of this study, the injection of high-viscosity bone cement via bilateral percutaneous vertebroplasty for patients who have osteoporotic vertebral compression fractures with intraosseous vacuum phenomena significantly relieved their back pains and improved their daily life activities shortly after the operation, thereby improving their life quality. In this study, the use of high-viscosity bone cement reduced the leakage rate and contributed to their successful treatment, as observed in patients during the 1-year follow-up period.

Percutaneous vertebroplasty guided by preoperative computed tomography measurements

BACKGROUND

Percutaneous vertebroplasty (PVP) is now widely performed to treat painful vertebral compression fractures. Previous researches have reported numerous advantages. However, it rarely reported that how to determine the feasibility of the unilateral or bilateral approach and how to decide the puncture angle, the skin insertion site before the procedure. The aim of this study was to discuss the feasibility of PVP using unilateral pedicular approach by the three-dimensional positioning of computed tomography (CT) image.

MATERIALS AND METHODS

Under fluoroscopic guidance, 108 patients with 115 diseased vertebral bodies underwent PVP. The study was divided in two groups. Group A, fifty patients with 52 vertebrae received PVP without using preoperative CT measurements and puncture simulation. Group B, 58 patients with 63 vertebrae received PVP using preoperative CT measurements and puncture simulation. The skin needle entry point and puncture angle of the transverse plane and sagittal plane were determined by the software of PACS on preoperative CT image. The choice of unilateral or bilateral pedicular approach was decided based on the CT image before the procedure. PVP was carried out according to the measurement result above. The average time for a single vertebra operation, the success rate of single puncture and complications was evaluated and compared between Group A and Group B.

RESULTS

In Group A, technical success of unilateral PVP was 63.5% (33/52 vertebrae), and 92% (58/63 vertebrae) in Group B. The average time of operation in Groups A and B were (37.5 ± 5.5) and (28.5 ± 5.5) min, respectively. There was a significant difference in the time of single-vertebra operation and the success rates of unilateral PVP between Groups A and B. No serious complications developed during the followup period.

CONCLUSIONS

The CT three-dimensional positioning measurement for PVP can increase the success rate of unilateral PVP.

Percutaneous vertebroplasty for osteoporotic vertebral compression fracture

BACKGROUND

Percutaneous vertebroplasty is widely used to treat acute and subacute painful osteoporotic vertebral fractures although recent placebo-controlled trials have questioned its value.

OBJECTIVES

To synthesise the available evidence regarding the benefits and harms of vertebroplasty for treatment of osteoporotic vertebral fractures.

SEARCH METHODS

We searched CENTRAL, MEDLINE and EMBASE up to November 2014. We also reviewed reference lists of review articles, trials and trial registries to identify any other potentially relevant trials.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials (RCTs) including adults with painful osteoporotic vertebral fractures of any duration and comparing vertebroplasty with placebo (sham), usual care, or any other intervention. As it is least prone to bias, vertebroplasty compared with placebo was the primary comparison. Major outcomes were mean overall pain, disability, disease-specific and overall health-related quality of life, patient-reported treatment success, new symptomatic vertebral fractures and number of other serious adverse events.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected trials for inclusion, extracted data, performed 'Risk of bias' assessment and assessed the quality of the body of evidence for the main outcomes using GRADE.

MAIN RESULTS

Eleven RCTs and one quasi-RCT conducted in various countries were included. Two trials compared vertebroplasty with placebo (209 randomised participants), six compared vertebroplasty with usual care (566 randomised participants) and four compared vertebroplasty with kyphoplasty (545 randomised participants). Trial size varied from 34 to 404 participants, most participants were female, mean age ranged between 63.3 and 80 years, and mean symptom duration varied from a week to more than six months.Both placebo-controlled trials were judged to be at low overall risk of bias while other included trials were generally considered to be at high risk of bias across a range of criteria, most seriously due to lack of participant and study personnel blinding.Compared with placebo, there was moderate quality evidence based upon two trials that vertebroplasty provides no demonstrable benefits with respect to pain, disability, disease-specific or overall quality of life or treatment success. At one month, mean pain (on a scale 0 to 10, higher scores indicate more pain) was 5 points with placebo and 0.7 points better (1.5 better to 0.15 worse) with vertebroplasty, an absolute pain reduction of 7% (15% better to 1.5% worse) and relative reduction of 10% (21% better to 2% worse) (two trials, 201 participants). At one month, mean disability measured by the Roland Morris Disability Questionnaire (scale range 0 to 23, higher scores indicate worse disability) was 13.6 points in the placebo group and 1.1 points better (2.9 better to 0.8 worse) in the vertebroplasty group, absolute improvement in disability 4.8% (12.8% better to 3.3% worse), relative change 6.3% better (17.0% better to 4.4% worse) (two trials, 201 participants).At one month, disease-specific quality of life measured by the QUALEFFO (scale 0 to 100, higher scores indicating worse quality of life) was 2.4 points in the placebo group and 0.40 points worse (4.58 better to 5.38 worse) in the vertebroplasty group, absolute change: 0.4% worse (5% worse to 5% better), relative change 0.7% worse (9% worse to 8% better (based upon one trial, 73 participants). At one month overall quality of life measured by the EQ5D (0 = death to 1 = perfect health, higher scores indicate greater quality of life at one month was 0.27 points in the placebo group and 0.05 points better (0.01 worse to 0.11 better) in the vertebroplasty group, absolute improvement in quality of life 5% (1% worse to 11% better), relative change 18% better (4% worse to 39% better) (two trials, 201 participants). Based upon one trial (78 participants) at one month, 9/40 (or 225 per 1000) people perceived that treatment was successful in the placebo group compared with 12/38 (or 315 per 1000; range 150 to 664) in the vertebroplasty group, RR 1.40 (95% CI 0.67 to 2.95), absolute risk difference 9% more reported success (11% fewer to 29% more); relative change 40% more reported success (33% fewer to 195% more).Based upon moderate quality evidence from three trials (one placebo, two usual care, 281 participants) with up to 12 months follow-up, we are uncertain whether or not vertebroplasty increases the risk of new symptomatic vertebral fractures (28/143 observed in the vertebroplasty group compared with 19/138 in the control group; RR 1.47 (95% CI 0.39 to 5.50).Similary, based upon moderate quality evidence from two placebo-controlled trials (209 participants), we are uncertain about the exact risk of other adverse events (3/106 were observed in the vertebroplasty group compared with 3/103 in the placebo group; RR 1.01 (95% CI 0.21 to 4.85)). Notably, serious adverse events reported with vertebroplasty included osteomyelitis, cord compression, thecal sac injury and respiratory failure.Our subgroup analyses provided limited evidence that the effects did not differ according to duration of pain ≤ 6 weeks versus > 6 weeks. Including data from the six trials that compared vertebroplasty with usual care in a sensitivity analyses inconsistently altered the primary results, with all combined analyses displaying substantial to considerable heterogeneity.

AUTHORS' CONCLUSIONS

Based upon moderate quality evidence, our review does not support a role for vertebroplasty for treating osteoporotic vertebral fractures in routine practice. We found no demonstrable clinically important benefits compared with a sham procedure and subgroup analyses indicated that results did not differ according to duration of pain ≤ 6 weeks versus > 6 weeks. Sensitivity analyses confirmed that open trials comparing vertebroplasty with usual care are likely to have overestimated any benefit of vertebroplasty. Correcting for these biases would likely drive any benefits observed with vertebroplasty towards the null, in keeping with findings from the placebo-controlled trials.Numerous serious adverse events have been observed following vertebroplasty. However due to the small number of events, we cannot be certain about whether or not vertebroplasty results in a clinically important increased risk of new symptomatic vertebral fractures and/or other serious adverse events. Patients should be informed about both the lack of high quality evidence supporting benefit of vertebroplasty and its potential for harm.

Cement augmentation in vertebral burst fractures

As a result of axial compression, traumatic vertebral burst fractures disrupt the anterior column, leading to segmental instability and cord compression. In situations with diminished anterior column support, pedicle screw fixation alone may lead to delayed kyphosis, nonunion, and hardware failure. Vertebroplasty and kyphoplasty (balloon-assisted vertebroplasty) have been used in an effort to provide anterior column support in traumatic burst fractures. Cited advantages are providing immediate stability, improving pain, and reducing hardware malfunction. When used in isolation or in combination with posterior instrumentation, these techniques theoretically allow for improved fracture reduction and maintenance of spinal alignment while avoiding the complications and morbidity of anterior approaches. Complications associated with cement use (leakage, systemic effects) are similar to those seen in the treatment of osteoporotic compression fractures; however, extreme caution must be used in fractures with a disrupted posterior wall.

Current status of percutaneous vertebroplasty and percutaneous kyphoplasty--a review

Percutaneous vertebroplasty (PV) and kyphoplasty (PK) are the 2vertebral augmentation procedures that have emerged as minimally invasive surgical options to treat painful vertebral compression fractures (VCF) during the last 2 decades. VCF may either be osteoporotic or tumor-associated. Two hundred million women are affected by osteoporosis globally. Vertebral fracture may result in acute pain around the fracture site, loss of vertebral height due to vertebral collapse, spinal instability, and kyphotic deformity. The main goal of the PV and PK procedures is to give immediate pain relief to patients and restore the vertebral height lost due to fracture. In percutaneous vertebroplasty, bone cement is injected through a minimal incision into the fractured site. Kyphoplasty involves insertion of a balloon into the fractured site, followed by inflation-deflation to create a cavity into which the filler material is injected, and the balloon is taken out prior to cement injection. This literature review presents a qualitative overview on the current status of vertebral augmentation procedures,especially PV and PK, and compares the efficacy and safety of these 2 procedures. The review consists of a brief history of the development of these 2 techniques, a discussion on the current research on the bone cement, clinical outcome of the 2 procedures, and it also sheds light on ongoing and future research to maximize the efficacy and safety of vertebral augmentation procedures.

Percutaneous vertebroplasty combined with interstitial implantation of 125I seeds in banna mini-pigs

BACKGROUND

Although brachytherapy is one of the most effective ways to treat metastatic spinal tumor with little damage to surrounding healthy tissue, it may cause radiation myelopathy if an overdose occurs. Establishing a valuable animal model can help to find a method to overcome its complications. In the current study, we set up a banna mini-pig model to mimic percutaneous vertebroplasty with 125I seed implantation.

METHODS

Percutaneous vertebroplasty (PVP) combined with interstitial implantation of 125I seeds, 125I seeds were transplanted into the vertebral body at the T13 level of the spine in banna mini-pigs. After raising them for up to eight months, the spinal cord and vertebral body were collected for pathological analysis.

RESULTS

A potential animal model had been successfully established, no case of radiation myelopathy was found in any of the treated banna pigs, and no significant cellular impairment was noted by pathological analysis.

CONCLUSIONS

It proves that PVP with 125I brachytherapy is an effective method to treat metastasis spinal tumor, and that the banna mini-pig can be a suitable model to investigate the mechanism of brachytherapy complications.

Does percutaneous kyphoplasty have better functional outcome than vertebroplasty in single level osteoporotic compression fractures? A comparative prospective study

Purpose. To evaluate the relative differences in surgical outcome of kyphoplasty (KP) versus vertebroplasty (VP) in the patients with single level refractory osteoporotic compression fractures (OCFs). Method. From August 2008 to May 2012, we intermittently treated 57 patients with single level OCF by PV and KP (Groups A and B, resp.). We used visual analogue scale (VAS) and short form 36 (SF36) questionnaire to measure functional recovery and followed them for six months. Independent samples t- and Kendall's tau-b tests were for statistics. Results. In terms of age, number, and bone mineral density of the patients, there were no significant differences between the two groups. In both groups, VAS and SF-36 scores improved significantly and remained relatively stable throughout the follow-up period. We had 9 and 6 asymptomatic cement extravasations and 5 and 8 new vertebral fractures in Group A and B, respectively. In comparing the two groups, the results indicated that KP almost failed to show any significant higher effect relative to VP during this period. Conclusions. In considering the high cost of KP relative to VP in the developing countries like Iran, there is no logical reason to use KP in a single level refractory OCF in these regions.

Neither subendplate cement deposition nor cement leakage into the disk space during vertebroplasty significantly affects patient outcomes

PURPOSE

To determine the impact of cement placement immediately adjacent to and through the endplate during percutaneous vertebroplasty on postprocedural pain and subsequent fracture rate.

MATERIALS AND METHODS

Institutional review board approval with waived consent was obtained. Medical records of 424 patients undergoing first-time, single-level vertebroplasty for osteoporotic or traumatic compression fractures were examined. Data regarding pain at rest and with activity before the procedure, along with timing and level of subsequent fractures over a 24-month period, were collected. Group 1 (n=64) included patients with no cement extension to the endplate(s), group 2 (n=216) included those with cement extension to the endplate(s) but no leakage into the disk space(s), and group 3 (n=144) included those with cement extension to the endplate(s) and cement leakage into the disk space(s). Analysis of variance and Fisher test were used to analyze the data, with significance set at P<.05.

RESULTS

Baseline characteristics and demographics were similar among the groups. At 1 month, for groups 1, 2, and 3, the respective mean postprocedural pain numeric scores at rest were 1.4±2.7, 1.4±2.4, and 1.6±2.5 (P=.51), while the respective pain scores with activity were 4.3±2.9, 3.8±3.1, and 3.9±3.3 (P=.50). Total subsequent fractures were noted in five (8%), 26 (12%), and 15 (10%) patients in group 1, 2, and 3, respectively (P=.77).

CONCLUSION

Neither extension of cement to the endplate nor cement leakage into the disk space has significant impact on postprocedural pain or subsequent fracture rate at 2 years.

FINITE ELEMENT ANALYSIS OF A MODEL OF SIMULATED VERTEBRAL CEMENT AUGMENTATION: INFLUENCE OF THE REPRESENTATION OF THE SHAPE OF THE CEMENT DOMAIN ON BIOMECHANICAL PARAMETERS

Vertebral cement augmentation is rapidly becoming the modality of choice for treating patients who are experiencing severe and persistent pain because of osteoporosis-induced vertebral compression fracture(s). The resulting cement domain (the part of the vertebral body (VB) filled with the cement) has an irregular or complicated shape. In literature reports of finite element analysis (FEA) of models of simulated vertebral cement augmentation, a variety of representations of the shape of the cement domain have been used. In the literature, only very limited attention has been given to the issue of the influence of cement domain shape representation on biomechanical parameters for a given combination of model and loading. This issue is the subject of the present work, with the model being of the L1-L3 motion segments. Augmentation of an unfractured L2 (prophylactic augmentation) was simulated, three cement domain shapes were considered — namely, solid cylinder, with rounded edges; two prolate spheroids; and oblate spheroid — and the applied loading comprised a simultaneous application of a uniform compressive pressure of 0.53 MPa (equivalent to an 800-N compression load) and a counter-clockwise-acting axial rotation moment of 1 Nm to the superior surface of L1. It was found that (1) while the cement domain shape representation has a marked influence on the mean von Mises stress (σAVM), the maximum von Mises stress (σMVM), and the strain energy density (MSED) distribution in the cement domain, its influence on each of these parameters in each of the biological tissues in the model as well as on the total segmental range of motion is minimal and (2) for σAVM and σMVM, the lowest value of each of these parameters was obtained when the oblate spheroid model was used. From both clinical and computational perspectives, these findings are significant. For example, the latter finding suggests that there is scope for researching the combination of key process variables used, such as the cement chemistry, the cement delivery system, and the augmentation technique/approach, that would ensure that the final cement domain shape in cement-augmented VBs of patients be oblate spheroid on a consistent and predictable basis.

Conservative management of patients with an osteoporotic vertebral fracture

Osteoporotic vertebral compression fractures (VCFs) are an increasing public health problem. Recently, randomised controlled trials on the use of kyphoplasty and vertebroplasty in the treatment of these fractures have been published, but no definitive conclusions have been reached on the role of these interventions. The major problem encountered when trying to perform a meta-analysis of the available studies for the use of cementoplasty in patients with a VCF is that conservative management has not been standardised. Forms of conservative treatment commonly used in these patients include bed rest, analgesic medication, physiotherapy and bracing.

In this review, we report the best evidence available on the conservative care of patients with osteoporotic VCFs and associated back pain, focusing on the role of the most commonly used spinal orthoses. Although orthoses are used for the management of these patients, to date, there has been only one randomised controlled trial published evaluating their value. Until the best conservative management for patients with VCFs is defined and standardised, no conclusions can be drawn on the superiority or otherwise of cementoplasty techniques over conservative management.

Unilateral extrapedicular vertebroplasty and kyphoplasty in lumbar compression fractures : technique, anatomy and preliminary results

OBJECTIVE

A single balloon extrapedicular kyphoplasty has been introduced as one of the unilateral approaches for thoracic compression fractures; however, the unilateral extrapedicular technique in the lumbar area needs a further understanding of structures in the lumbar area. The purpose of the present study is to describe methods and pitfalls of this procedure based on the anatomy of the lumbar area and to analyze clinical outcome and complications.

METHODS

Anatomical evaluation was performed with 2 human cadavers. A retrospective review of unilateral extrapedicular approaches yielded 74 vertebral levels in 55 patients that were treated with unilateral extrapedicular vertebroplasty and kyphoplasty. Radiographic assessment included the restoration rate of vertebral height and correction of kyphosis.

RESULTS

Anatomical evaluation indicates that the safe needle entry zone of bone for the extrapedicular approach was located in the supero-lateral aspect of the junction between the pedicle and vertebral body. The unilateral extrapedicular procedure achieved adequate pain relief with a mean decreases in pain severity of 7.25±1.5 and 2.0±1.4, respectively. Complications were 1 retroperitoneal hematoma, 6 unilateral fillings and 3 epidural leak of the polymethylmethacrylate.

CONCLUSION

The method of a unilateral extrapedicular approach in kyphoplasty and vertebroplasty in the lumbar area might be similar to that in thoracic approach using a route via the extrapedicular space. However, different anatomical characteristics of the lumbar area should be considered.

Utility of bone scintigraphy to determine the appropriate vertebral augmentation levels

PURPOSE OF THE REPORT

Vertebral augmentation procedures have been used as an effective treatment for back pain due to vertebral compression fracture from different causes, including metastatic disease and osteoporosis. However, diagnosis and localization of the causative vertebral level(s) may be difficult using any single imaging modality. In this retrospective study, we assessed the ability of preprocedural bone scans to determine the appropriate level(s) of subsequent vertebroplasty.

MATERIALS AND METHODS

The study consisted of a retrospective chart review of 44 patients who underwent bone scintigraphs and vertebroplasties at Montefiore Medical Center from 2002 to 2008. Online medical records and reports were used to determine the level of vertebroplasty and the preprocedure bone scan levels. The data was reviewed by a panel consisting of a neuroradiologist and nuclear medicine physician for agreement.

RESULTS AND CONCLUSIONS

Our retrospective study assessed the utility of bone scans as a diagnostic tool to identify candidate vertebral levels for vertebroplasty and determined that bone scans were positive in 78.3% of all fractures that subsequently underwent vertebral augmentation procedures. Although no significant difference was seen in the positivity of bone scans to subsequent vertebroplasty levels between benign or metastatic compression fractures (79% vs. 76%), a difference was observed when single level vertebroplasty patients were compared with multiple-level vertebroplasty patients (87% vs. 69%). Our results support the use of whole body bone scintigraphy as a diagnostic tool prior to vertebroplasty, especially in cases where a single vertebral level is involved or MRI might be contraindicated.

Calcium-strontium mixed phosphate as novel injectable and radio-opaque hydraulic cement

Sterile calcium hydrogenophosphate dihydrate (DCPD) (CaHPO(4).2H(2)O), calcium oxide and strontium carbonate powders were mixed in various liquid phases. Among these, ammonium phosphate buffer (0.75 M, pH 6.9) led to a novel strontium-containing calcium phosphate cement. At a 6/2.5/1.5 M ratio and for a liquid to powder ratio (L/P) of 0.5 mlg(-1), the initial paste was fluid and remained injectable for 12 min at 25 degrees C. It was easily obtained by mixing sterile powders and the liquid phase using the push-pull technique, avoiding complex mixing apparatus. The cement set after 15 min at 37 degrees C and was hard after 1h. The compressive strength was in the 20 MPa range, a value higher than that generally assigned to trabecular bone (5-15MPa). This strength appeared sufficient for repairing non-loading sites or reinforcing osteoporotic vertebrae (vertebroplasty). After setting, the initial mixture formed a strontium-calcium-deficient carbonate apatite. The radio-opacity of the resulting cement was three times greater than that of cortical bone because of the presence of strontium ions, a feature that complies with the requirements for vertebroplasty. Furthermore, the cement powder remained stable and retained its properties for at least 4 years.

Characterization of polymeric solutions as injectable vehicles for hydroxyapatite microspheres

A polymeric solution and a reinforcement phase can work as an injectable material to fill up bone defects. However, the properties of the solution should be suitable to enable the transport of that extra phase. Additionally, the use of biocompatible materials is a requirement for tissue regeneration. Thus, we intended to optimize a biocompatible polymeric solution able to carry hydroxyapatite microspheres into bone defects using an orthopedic injectable device. To achieve that goal, polymers usually regarded as biocompatible were selected, namely sodium carboxymethylcellulose, hydroxypropylmethylcellulose, and Na-alginate (ALG). The rheological properties of the polymeric solutions at different concentrations were assessed by viscosimetry before and after moist heat sterilization. In order to correlate rheological properties with injectability, solutions were tested using an orthopedic device applied for minimal invasive surgeries. Among the three polymers, ALG solutions presented the most suitable properties for our goal and a non-sterile ALG 6% solution was successfully used to perform preliminary injection tests of hydroxyapatite microspheres. Sterile ALG 7.25% solution was found to closely match non-sterile ALG 6% properties and it was selected as the optimal vehicle. Finally, sterile ALG 7.25% physical stability was studied at different temperatures over a 3-month period. It was observed that its rheological properties presented minor changes when stored at 25 degrees C or at 4 degrees C.

Percutaneous CT-guided vertebroplasty in the management of osteoporotic fractures and dorsolumbar metastases

Percutaneous vertebroplasty (PVP) is a minimally invasive, image-guided procedure consisting of an injection of acrylic cement into a vertebral body to reinforce the compressed segment and achieve pain relief. The use of PVP is a minimally invasive option in the treatment of osteoporotic or metastatic vertebral collapses. Our personal experience, using a CT-guided technique, confirms the efficacy and safety of PVP with a lower risk for complications compared with conventional fluoroscopic approaches because of a precise placement of the instruments in the vertebral body and an early detection of small cement leakages.

Vertebroplasty and kyphoplasty: reasons for concern?

Two different minimally invasive percutaneous vertebral augmentation methods for cement application into the vertebral body for the management of symptomatic compression fractures without neurologic impairment have been developed, namely, vertebroplasty and kyphoplasty. In vertebroplasty, polymethylmethacrylate cement is injected percutaneously into a collapsed vertebral body. Kyphoplasty involves placing an inflatable bone tamp percutaneously into a vertebral body. The inflation of the bone tamp with fluid allows restoration of vertebral height and correction of the kyphosis. After deflation, the cavity that has been produced is filled by injection of polymethylmethacrylate. This article provides an overview of the state of the art in vertebroplasty and kyphoplasty, discussing the indications, techniques, results, and pitfalls.

Preliminary biomechanical evaluation of prophylactic vertebral reinforcement adjacent to vertebroplasty under cyclic loading

BACKGROUND CONTEXT

Percutaneous vertebroplasty has become a favored treatment option for reducing pain in osteoporotic patients with vertebral compression fractures (VCFs). Short-term results are promising, although longer-term complications may arise from accelerated failure of the adjacent vertebral body.

PURPOSE

To provide a preliminary biomechanical assessment of prophylactic vertebral reinforcement adjacent to vertebroplasty using a three-vertebra cadaveric segment under dynamic loads that represent increasing activity demands. In addition, the effects of reducing the elastic modulus of the cement used in the intact vertebrae were also assessed.

STUDY DESIGN/SETTING

Three-vertebra cadaveric segments were used to evaluate vertebroplasty with adjacent vertebral reinforcement as an intervention for VCFs.

METHODS

Nine human three-vertebra segments (T12-L2) were prepared and a compression fracture was generated in the superior vertebrae. Vertebroplasty was performed on the fractured T12 vertebra. Subsequently, the adjacent intact L1 vertebra was prophylactically augmented with cement of differing elastic moduli (100-12.5% modulus of the base cement value). After subfailure quasi-static compression tests before and after augmentation, these specimens were subjected to an incrementally increasing dynamic load profile in proportion to patient body weight (BW) to assess the fatigue properties of the construct. Quantitative computed tomography assessments were conducted at several stages in the experimental process to evaluate the vertebral condition and quantify the gross dimensions of the segment.

RESULTS

No significant difference in construct stiffness was found pre- or postaugmentation (t=1.4, p=.19). Displacement plots recorded during dynamic loading showed little evidence of fracture under normal physiological loads or moderate activity (1-2.5x BW). A third of the specimens continued to endure increasing load demands and were confirmed to have no fracture after testing. In six specimens, however, greater loads induced 11 fractures: 7 in the augmented vertebra (2xT12, 5xL5) and 4 in the adjacent L2 vertebra. A strong correlation was observed between the subsidence in the segmental unit and the incidence of fracture after testing (r(Spearman's)=-0.88, p=.002). Altering the modulus of cement in the intact vertebra had no effect on level of segmental compromise.

CONCLUSIONS

These preliminary findings suggest that under normal physiological loads associated with moderate physical activity, prophylactic augmentation adjacent to vertebroplasty showed little evidence of inducing fractures, although loads representing more strenuous activities may generate adjacent and peri-augmentation compromise. Reducing the elastic modulus of the cement in the adjacent intact vertebrae appeared to have no significant effect on the incidence or location of the induced fracture or the overall height loss of the vertebral segment.

New injectable and radiopaque antibiotic loaded acrylic bone cements

The use of antibiotic loaded bone cements (ALBCs) has become a common clinical practice in the prevention and treatment of prosthesis-related infections. However, due to antibiotic resistance, there is a general interest in broadening the antibacterial spectrum of currently used drugs. The aim of this work is to formulate ALBCs for specific use in vertebroplasty and kyphoplasty, and to study the effect of the addition of ciprofloxacin alone and in combination with vancomycin on some properties of the cement. The cements were formulated using bismuth salicylate as the radiopacifier. The setting properties, residual monomer content, release of antibiotics, rheological behavior, injectability, and mechanical properties of these formulations were studied. They showed long setting times and low curing temperatures. From the release studies, antibacterial properties are assumed because the concentration of released antibiotic was higher than the minimum effective. Although the experimental cements had slightly reduced mechanical properties, the other alterations shown were negligible.

The biomechanics of vertebroplasty in multiple myeloma and metastatic bladder cancer: a preliminary cadaveric investigation

Object

The vertebral column is the most common site for secondary bone metastases and lesions arising from hematological malignancies such as multiple myeloma (MM). These infiltrations can be lytic in nature and cause severe weakening of the vertebral body, an increased risk of fracture, and spinal cord compression leading to neurological deficit. Qualitatively it is apparent that increasing infiltration of these lytic lesions will have a deleterious effect on the mechanical behavior of the vertebrae. However, there is little quantitative information about the relationship between tumor deposits and the impact on the mechanical behavior of the vertebrae. In addition, there have been limited biomechanical assessments of the use of vertebroplasty in the management of these malignancies. The purpose of this preliminary study was to evaluate the mechanical behavior of lesion-infiltrated vertebrae from 2 malignant cancers and to investigate the effectiveness of vertebroplasty with and without tumor debulking.

Methods

Individual vertebrae from 2 donor spines—one with MM and another with bone metastases secondary to bladder cancer—were fractured under an eccentric flexion load, from which failure strength and stiffness were derived. Alternate vertebrae defined by spinal level were assigned to 2 groups: Group 1 involved removal of lesion material with Coblation (ArthroCare Corp.) preceding vertebroplasty; Group 2 received no Coblation prior to augmentation. All vertebrae were fractured postaugmentation under the same loading protocol. Micro-CT assessments were undertaken to investigate vertebral morphology, fracture patterns, and cement distribution.

Results

Multiple myeloma involvement was characterized by several small lesions, severe bone degradation, and multiple areas of vertebral shell compromise. In contrast, large focal lesions were present in the vertebrae with metastatic bladder cancer, and the shell generally remained intact. The mean initial failure strength of the vertebrae with metastases secondary to MM was significantly lower than in vertebrae with bone metastases secondary to bladder cancer (Load = 950 ± 300 N vs 2200 ± 750 N, p < 0.0001). A significant improvement in relative fracture strength was found postaugmentation for both lesion types (1.4 ± 0.5, p < 0.001). Coblation provided a marginally significant increase in the same parameter postaugmentation (p = 0.08) and qualitatively improved the ease of injection and guidance of cement.

Conclusions

In the vertebral column, metastatic lesions secondary to bladder cancer and MM showed variations in the pattern of infiltration, both of which led to significant reductions in fracture strength. Account should be taken of these differences to optimize the vertebroplasty intervention in terms of the cement formulation, delivery, and any additional surgical procedure.

Minimally invasive anterior vertebroplasty for C-2 metastatic lesions

The authors describe a technique for minimally invasive anterior vertebroplasty for treating metastatic disease of the C-2 vertebra and discuss its application in 2 cases. After a 2-cm lateral neck incision is made, blunt dissection is performed toward the anterior inferior endplate of the C-2 vertebra. An 11-gauge needle is introduced through a tubular sheath and tapped into the inferior endplate of C-2, with biplanar fluoroscopy being performed to confirm position. The needle is subsequently advanced across the fracture line and into the odontoid process. Under fluoroscopic guidance, 2 ml of methylmethacrylate is injected into the odontoid process and vertebral body. This method is advantageous as 1) hyperextension of the neck is not performed, 2) the chance of inadvertent neurovascular or submandibular gland injury is minimized, 3) the possibility of cement leakage is decreased, and 4) hemostasis is better achieved under direct vision.

The biomechanical effectiveness of prophylactic vertebroplasty: a dynamic cadaveric study

OBJECT

The purpose of the study was to investigate the segmental effects of prophylactic vertebroplasty under increasingly demanding loading conditions and to assess the effect of altered cement properties on the construct biomechanics.

METHODS

Twelve human cadaveric 3-vertebral functional spinal units (T12-L2) were prepared such that the intact L-1 vertebra was prophylactically augmented with cements of differing elastic moduli (100, 50, 25, and 12.5% modulus of the base cement). These specimens were subjected to quasistatic subfailure compression pre- and postaugmentation to 50% of the predicted failure strength and then cyclic loading in a fatigue rig (115,000 cycles) to characterize the high-stress, short-cycle fatigue properties of the construct. Loading was increased incrementally in proportion to body weight to a maximum of 3.5 x body weight. Quantitative computed tomography assessment was conducted pre- and postaugmentation and following cyclic testing to assess vertebral condition, cement placement, and fracture classification.

RESULTS

Adjacent and periaugmentation fractures were induced in the prophylactically augmented segments. However, it appeared that these fractures mainly occurred when the specimens were subjected to loads beyond those that may commonly occur during most normal physiological activities.

CONCLUSIONS

Lowering the elastic modulus of the cement appeared to have no significant effect on the frequency or severity of the induced fracture within the vertebral segment.

Comparison of CT characteristics of extravertebral cement leakages after vertebroplasty performed by different navigation and injection techniques

OBJECTIVE

This study was intended to assess the results of post-operative CT scans in three groups of patients following percutaneous vertebroplasty (VP) using different navigation and injection methods, in an attempt to explain the radiological characteristics of extravertebral cement leakage with relation to needle placement and focused on the ventral epidural accumulation of bone cement. Furthermore, we have suggested a morphological (and functional) classification of the types of cement leakage.

METHODS

Between July 2001 and February 2005, 123 percutaneous VP procedures were performed during 75 sessions in 65 patients for treatment of painful osteoporotic vertebral body compression fractures. These included:- Group I: 28 patients, 33 sessions; 50 right sided unilateral VP under fluoroscopic control with central position of the tip of the needle within the bone marrow. Group II: 27 patients, 28 sessions; 50 bilateral VP under fluoroscopic control with separate cement injections into both "hemivertebrae". Group III: 14 patients, 14 sessions; 23 bilateral VP navigated by frameless stereotaxy (neuronavigation). Needles were positioned strictly into the lateral thirds of the vertebral bodies. Leakages were classified as epidural, foraminal, intradiscal, venous paravertebral, compact extravertebral on the post-operative CT scans, and their frequency was compared in relation to the navigation method and the position of the tip of the needle.

RESULTS

Group I: extravertebral cement was detected in 23 patients (82%), and in 35 (70%) of the 50 vertebrae treated (ventral epidural: 23 vertebrae = 46%; intradiscal: 12 vertebrae = 24%; venous paravertebral: 8 vertebrae = 16%; intraforaminal: 7 vertebrae = 14%; and compact extravertebral: 3 vertebrae = 6%). Group II: extravertebral cement was detected in 20 patients (74%), and in 38 (76%) of the 50 vertebrae treated (ventral epidural: 12 vertebrae = 24%; intradiscal: 12 vertebrae = 24%; venous paravertebral: 9 vertebrae = 18%; and foraminal: 1 vertebra = 2%). Group III: extravertebral cement could be detected in 10 patients (71%), and in 10 (43%) of the 23 vertebrae treated (ventral epidural: 3 vertebrae = 13%; intradiscal: 8 vertebrae = 34%; venous paravertebral: 4 vertebrae = 17%).

CONCLUSION

The incidence of epidural accumulation of bone cement may be concluded to be closely correlated with the position of the tip of the needle. Centrally injected bone cement may easily invade into the basivertebral system, and the material can then be transferred via these veins toward the ventral epidural space, and result in canal compromise and/or compression of the neural elements. The results of statistical analysis (Chi-square test) revealed that injection of bone cement into the lateral third of the vertebral body significantly decreases the extent of ventral epidural leakage. Therefore, a strictly lateral injection is advised, when the tip of the needle is placed into the lateral third of the vertebral body. Frameless stereotaxy navigation improves achievement of accurate needle placement and decreases the frequency of ventral epidural leakage. It is a safe and very accurate method for positioning of the injecting needles.

Interventional techniques for back pain

Most Americans will be afflicted by some form of spine-related pain in their lifetime. In older patients, the most frequent source of back pain is lumbar spinal stenosis or vertebral compression fracture. Although most back pain is self-limited, some patients will require interventional techniques. This article reviews minimally invasive techniques for treating back pain, lumbosacral radicular pain, lumbar spinal stenosis, and compression fractures.

Vertebroplasty and kyphoplasty

Vertebral compression fractures occur more frequently than hip and ankle fractures combined. These fragility fractures frequently result in both acute and chronic pain, but more importantly are a source of increased morbidity and possibly mortality. Percutaneous veretebral augmentation offers a minimally invasive approach for the treatment of vertebral compression fractures. The history, technique, and results of vertebroplasty and kyphoplasty are reviewed. Both methods allow for the introduction of bone cement into the fracture site with clinical results indicating substantial pain relief in approximately 90% of patients.

CT-guided percutaneous vertebroplasty: personal experience in the treatment of osteoporotic fractures and dorsolumbar metastases

PURPOSE

This study was performed to evaluate the results and complications of percutaneous vertebroplasty (PVP) performed under CT guidance.

MATERIALS AND METHODS

We treated 106 patients (182 PVP): 67 for osteoporotic vertebral compression fracture, and 39 for osteolytic metastases. The first 78 patients were treated using computed tomography (CT) combined with conventional fluoroscopy as an imaging guide (135 PVP). In 28 patients, the procedure was performed with multislice CT fluoroscopy (47 PVP).

RESULTS

Partial or complete pain relief was obtained in 98% of patients within 24 h from the treatment; significant results were also obtained with regard to improvement in functional mobility and reduction of analgesic use. CT allowed the detection of cement leakage in 43.9%. Severe complications were one case of pneumothorax and two cases of symptomatic cement leakage. Mild complications included two cases of cement pulmonary embolism. During the follow-up, eight osteoporotic patients presented a new vertebral fracture, and new vertebral metastases appeared in two oncological patients.

CONCLUSIONS

Our personal experience confirms the efficacy of PVP treatment for both osteoporotic and oncological patients. The use of CT guidance reduces the risk of complications in comparison with conventional fluoroscopy alone, as well as facilitates the detection of small cement leakages.

A biomechanical investigation of vertebroplasty in osteoporotic compression fractures and in prophylactic vertebral reinforcement

STUDY DESIGN

Cadaveric single vertebrae were used to evaluate vertebroplasty as a prophylactic treatment and as an intervention for vertebral compression fractures.

OBJECTIVE

To investigate the biomechanical characteristics of prophylactic reinforcement and postfracture augmentation of cadaveric vertebrae.

SUMMARY OF BACKGROUND DATA

Percutaneous vertebroplasty is a treatment option for osteoporotic vertebral compression fractures. Short-term results are promising, but longer-term studies have suggested a possible accelerated failure rate in the adjacent vertebral body. Limited research has been conducted into the effects of prophylactic vertebroplasty in osteoporotic vertebrae. This study aims to elucidate the biomechanical differences between the 2 treatment groups.

METHODS

Human vertebrae were assigned to 2 scenarios: Scenario 1 simulated a wedge fracture followed by cement augmentation; Scenario 2 involved prophylactic augmentation using vertebroplasty. Micro-CT imaging was performed to assess the bone mineral density, vertebral dimensions, fracture pattern, and cement volume. All augmented specimens were then compressed under an eccentric flexion load to failure.

RESULTS

Product of bone mineral density and endplate surface area gave a good prediction of failure strength when compared with actual failure strength of specimens in Scenario 1. Augmented vertebral bodies showed an average cement fill of 23.9% +/- 8.07%. There was a significant postvertebroplasty increase in failure strength by a factor of 1.72 and 1.38 in Scenarios 1 and 2, respectively. There was a significant reduction in stiffness following augmentation for Scenario 1 (t = 3.5, P = 0.005). Stiffness of the vertebral body in Scenario 2 was significantly greater than observed in Scenario 1 (t = 4.4, P = 0.0002).

CONCLUSION

Results suggest that augmentation of the vertebrae postfracture significantly increases failure load, while stiffness is not restored. Prophylactic augmentation was seen to increase failure strength in comparison to the predicted failure load. Stiffness appears to be maintained suggesting that prophylactic vertebroplasty maintains stiffness better than vertebroplasty postfracture.