Intravertebral pressure during vertebroplasty and balloon kyphoplasty: an in vitro study

A digital twin for simulating the vertebroplasty procedure and its impact on mechanical stability of vertebra in cancer patients

We present the application of ReconGAN, introduced in a previous study, for simulating the vertebroplasty (VP) operation and its impact on the fracture response of a vertebral body. ReconGAN consists of a Deep Convolutional Generative Adversarial Network (DCGAN) and a finite element based shape optimization algorithm to virtually reconstruct the trabecular bone microstructure. The VP procedure involves injecting shear-thinning liquid bone cement through a needle in the trabecular region to reinforce a diseased or fractured vertebra. To simulate this treatment modality, computational fluid dynamics (CFD) is employed to predict the morphology of the injected cement within the bone microstructure. A power-law equation is utilized to characterize the non-Newtonian shear-thinning behavior of the polymethyl methacrylate (PMMA) bone cement during injection simulations. The CFD model is coupled with the level-set method to simulate the motion of the interface separating bone cement and bone marrow. After predicting the cement morphology, a data co-registration algorithm is employed to transform the CFD model to a high-fidelity continuum damage mechanics (CDM) finite element model of the augmented vertebra for predicting the fracture response. A feasibility study is presented to demonstrate the ability of this CFD-CDM framework to investigate the effect of VP on the mechanical integrity of the vertebral body in a cancer patient with a lytic metastatic tumor.

Risk factors for pulmonary cement embolism associated with percutaneous vertebral augmentation: A systematic review and meta-analysis

BACKGROUND

Pulmonary cement embolism (PCE) was a rare but fatal complication for percutaneous vertebral augmentation (PVA). Thus we did a systematic review and meta-analysis of cohort studies to investigate the risk factors for PCE after PVA.

METHODS

We systematically searched PubMed, EMBASE, Cochrane library, Google Scholar, web of science, and ClinicalTrial.gov from the establishment of the database to September 2021. All eligible studies assessing the risk factors for PCE after PVA were incorporated. Dichotomous data was calculated by risk difference (RD) from Mantel-Haenszel method (M - H method); continuous data was analyzed by mean difference (MD) from Inverse-Variance method (I-V method). All variables were taken as measure of effect by fixed effect model. Heterogeneity, sensitivity, and publication bias analyses were also performed.

RESULTS

This study totally included 13 studies. According to the Newcastle-Ottawa Scale (NOS), 7 studies were considered as low quality, with NOS< 6. The others were of relatively high quality, with NOS≥6. 144/6251 patients (2.3%) had PCE after PVA. percutaneous vertebroplasty (PVP) (RD = 0.02, 95%CI: [0.01, 0.04], Z = 3.70, P < 0.01), thoracic vertebra (RD = 0.03, 95%CI: [0.01, 0.05], Z = 3.53, P < 0.01), higher cement volume injected per level (MD = 0.23, 95%CI: [0.05, 0.42], Z = 2.44, P = 0.01), more than three vertebrae treated per session (MD = -0.05, 95%CI: [-0.08, -0.02], Z = 3.65, P < 0.01), venous cement leakage (RD = 0.07, 95%CI: [0.03, 0.11], Z = 3.79, P < 0.01) were more likely to cause PCE.

CONCLUSION

This study showed that risk factors for PCE included PVP, thoracic vertebra, higher cement volume injected per level, more than three vertebrae treated per session, venous cement leakage. As a serious complication, PCE should be paid attention and avoided.

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.

Fenestrated pedicle screws for thoracolumbar instrumentation in patients with poor bone quality: Case series and systematic review of the literature

OBJECTIVE

To describe the results of a single-surgeon series and systematically review the literature on cement-augmented instrumented fusion with fenestrated pedicle screws.

METHODS

All patients treated by the senior surgeon using fenestrated screws between 2017 and 2019 with a minimum of 6-months of clinical and radiographic follow-up were included. For the systematic review, we used PRISMA guidelines to identify all prior descriptions of cement-augmented instrumented fusion with fenestrated pedicle screws in the English literature. Endpoints of interest included hardware loosening, cement leakage, and pulmonary cement embolism (PCE).

RESULTS

Our series included 38 patients (mean follow-up 14.8 months) who underwent cement-augmented instrumentation for tumor (47.3%), deformity/degenerative disease (39.5%), or osteoporotic fracture (13.2%). Asymptomatic screw lucency was seen in 2.6%, cement leakage in 445, and pulmonary cement embolism (PCE) in 5.2%. Our literature review identified 23 studies (n = 1526 patients), with low reported rates of hardware loosening (0.2%) and symptomatic PCE (1.0%). Cement leakage, while common (55.6%), produced symptoms in fewer than 1% of patients. Indications for cement-augmentation in this cohort included: spine metastasis with or without pathologic fracture (n = 18; 47.3%), degenerative spine disease or fixed deformity with poor underlying bone quality (n = 15; 39.5%), and osteoporotic fracture (n = 5; 13.2%).

CONCLUSION

Cement-augmented fusion with fenestrated screws appears to be a safe, effective means of treating patients with poor underlying bone quality secondary to tumor or osteoporosis. High-quality evidence with direct comparisons to non-augmented patients is needed.

Analysis of two minimally invasive procedures for osteoporotic vertebral compression fractures with intravertebral cleft: a systematic review and meta-analysis

Background

A systematic review and meta-analysis to assess the pros and cons of percutaneous vertebroplasty (PVP) versus kyphoplasty (PKP) for osteoporotic vertebral compression fractures (OVCFs) with intravertebral cleft (IVC) including all available evidence from controlled trials.

Methods

Databases including Pubmed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang Data were searched to identify relevant studies comparing PVP and PKP for OVCFs with IVC. The outcomes mainly included visual analog scale (VAS), Oswestry Disability Index (ODI), local kyphotic angle (LKA), rate of vertebral height (VH%), and adverse events.

Results

Nine studies enrolling 688 patients were eligible for meta-analysis. The results indicated no significant differences between the two groups in the short-and long-term VAS, ODI, LKA, or VH% (P > 0.05). Compared with PVP, PKP was associated with significantly longer operation time (P < 0.05), higher cost (P > 0.05), and more injected cement volume (P < 0.05). In terms of adverse events, PKP has a lower risk of cement leakage (P < 0.05), while with no significant difference in adjacent-level fracture rates (P > 0.05).

Conclusion

The two procedures have similar short- and long-term pain relief, functional recovery, local kyphosis correction, and vertebral height maintenance in OVCFs with IVC. PKP is superior to PVP for the injected cement volume, and lower cement leakage rate, however, with longer operation time, more fluoroscopy times, and higher cost. Further randomized controlled trials (RCTs) should be conducted to confirm these results.

Pulmonary Embolism from Cement Augmentation of the Vertebral Body

Pulmonary cement embolism (PCE) can follow cement augmentation procedures for spine fractures due to osteoporosis, traumatic injuries, and painful metastatic lesions. PCE is underreported and it is likely that many cases remain undiagnosed. Risk factors for PCE have been identified, which can help alert clinicians to patients likely to develop the condition, and there are recommended techniques to reduce its incidence. Most patients with PCE are asymptomatic or only develop transient symptoms, although a few may exhibit florid cardiorespiratory manifestations which can ultimately be fatal. Diagnosis is mainly by radiographic means, commonly using simple radiographs and computed tomography scans of the chest with ancillary tests that assess the patient's cardiorespiratory condition. Management depends on the location and size of the emboli as well as the patient's symptomatology. The aim of this review is to raise awareness of the not uncommon complications of PCE following vertebral cement augmentation and the possibility of serious sequelae. Recommendations for the diagnosis and management of PCE are presented, based on the most recent literature.

The impact of endplate fracture on postoperative vertebral height loss and kyphotic deformity during treatment of osteoporotic vertebral compression fractures with balloon kyphoplasty

This retrospective study investigated the impact of endplate fracture on postoperative vertebral height loss and kyphotic deformity in 144 patients with osteoporotic vertebral compression fracture (OVCF), who received balloon kyphoplasty. Patients were divided into four groups: Group 1 had no superior endplate fracture, Group 2 had fractures on the anterior portion of the superior endplate, Group 3 had fractures on the posterior portion of the superior endplate, and Group 4 had complete superior endplate fractures. Anterior and middle vertebral body height, vertebral compression ratio, vertebral height loss rate, and kyphosis Cobb angle of each patient were measured and visual analogue scale (VAS) and Oswestry disability index (ODI) scores were recorded. The anterior vertebral height and kyphosis deformity of all groups significantly improved after the surgery, whereas substantial anterior vertebral height loss and increased Cobb angle were observed in all patients at the last follow-up. Although the vertebral height loss rate and the Cobb angle in Group 2, 3 and 4 were larger compared with Group 1 at the last follow-up, only the vertebral height loss rate in Group 4 and the increase in the Cobb angle in Group 2 and 4 were statistically different from those in Group 1. The VAS and ODI scores in all groups measured after the surgery and at the last follow-up were significantly lower compared with preoperative scores, but there was no significant difference among these groups. Balloon kyphoplasty significantly improved vertebral fracture height and kyphosis. Vertebral height loss and increased kyphotic deformity were observed in OVCF patients with endplate fractures after the surgery. Postoperative aggravation of kyphosis was observed in Group 2. Furthermore, severe vertebral height loss and increased kyphotic deformity were confirmed in Group 4 after the surgery. Our results suggested that postoperative vertebral height loss and aggravation of kyphosis may be associated with biomechanical changes in the vertebral body caused by endplate fracture. Therefore, surgery should not only restore compressed vertebral body height and correct kyphosis, but also correct the deformity of endplate to achieve an effective treatment of OVCF patients with endplate fracture.

The biomechanics of pedicle screw augmentation with cement

BACKGROUND CONTEXT

A persistent challenge in spine surgery is improving screw fixation in patients with poor bone quality. Augmenting pedicle screw fixation with cement appears to be a promising approach.

PURPOSE

The purpose of this study was to survey the literature and assess the previous biomechanical studies on pedicle screw augmentation with cement to provide in-depth discussions of the biomechanical benefits of multiple parameters in screw augmentation.

STUDY DESIGN/SETTING

This is a systematic literature review.

METHODS

A search of Medline was performed, combining search terms of pedicle screw, augmentation, vertebroplasty, kyphoplasty, polymethylmethacrylate, calcium phosphate, or calcium sulfate. The retrieved articles and their references were reviewed, and articles dealing with biomechanical testing were included in this article.

RESULTS

Polymethylmethacrylate is an effective material for enhancing pedicle screw fixation in both osteoporosis and revision spine surgery models. Several other calcium ceramics also appear promising, although further work is needed in material development. Although fenestrated screw delivery appears to have some benefits, it results in similar screw fixation to prefilling the cement with a solid screw. Some differences in screw biomechanics were noted with varying cement volume and curing time, and some benefits from a kyphoplasty approach over a vertebroplasty approach have been noted. Additionally, in cadaveric models, cemented-augmented screws were able to be removed, albeit at higher extraction torques, without catastrophic damage to the vertebral body. However, there is a risk of cement extravasation leading to potentially neurological or cardiovascular complications with cement use. A major limitation of these reviewed studies is that biomechanical tests were generally performed at screw implantation or after a limited cyclic loading cycle; thus, the results may not be entirely clinically applicable. This is particularly true in the case of the bioactive calcium ceramics, as these biomechanical studies would not have measured the effects of osseointegration.

CONCLUSIONS

Polymethylmethacrylate and various calcium ceramics appear promising for the augmentation of pedicle screw fixation biomechanically in both osteoporosis and revision spine surgery models. Further translational studies should be performed, and the results summarized in this review will need to be correlated with the clinical outcomes.

The effect of void creation prior to vertebroplasty on intravertebral pressure and cement distribution in cadaveric spines with simulated metastases

Background

For osteoporosis or spinal metastases, percutaneous vertebroplasty is effective in pain relief and improvement of mobility. However, the complication rate (cement extravasation and fat embolisms) is relatively higher in the treatment of spinal metastases. The presence of tumor tissue plays a significant role in intravertebral pressure and cement distribution and thereby affects the occurrence of complications. We investigated the effect of void creation prior to vertebroplasty on intravertebral pressure and cement distribution in spinal metastases.

Methods

Eighteen vertebrae (T8–L4) from five cadaveric spines were randomly allocated for two groups (group with and without void) of nine vertebrae each. Defect was created by removing a central core of cancellous bone in the vertebral body and then filling it with 30% or 100% fresh muscle paste by volume to simulate void creation or no void creation, respectively. Then, 20% bone cement by volume of the vertebral body was injected into each specimen through a unipedicular approach at a rate of 3 mL/min. The gender of the donor, vertebral body size, bone density, cement volume, and intravertebral pressure were recorded. Then, computed tomography scans and cross sections were taken to evaluate the cement distribution in vertebral bodies.

Results

No significant difference was found between the two groups in terms of the gender of the donor, vertebral body size, bone density, or bone cement volume. The average maximum intravertebral pressure in the group with void creation was significantly lower than that in the group without void creation (1.20 versus 5.09 kPa, P = 0.001). Especially during the filling of void, the difference was more pronounced. Void creation prior to vertebroplasty allowed the bone cement to infiltrate into the lytic defect.

Conclusions

In vertebroplasty for spinal metastases, void creation produced lower intravertebral pressure and facilitated cement filling. To reduce the occurrence of complication, it may be an alternative to eliminate the tumor tissue to create a void prior to cement injection.

Risks and benefits of percutaneous vertebroplasty or kyphoplasty in the management of osteoporotic vertebral fractures

Vertebral fracture (VF) is the most common osteoporotic fracture and is associated with high morbidity and mortality. Conservative treatment combining antalgic agents and rest is usually recommended for symptomatic VFs. The aim of this paper is to review the randomized controlled trials comparing the efficacy and safety of percutaneous vertebroplasty (VP) and percutaneous balloon kyphoplasty (KP) versus conservative treatment. VP and KP procedures are associated with an acceptable general safety. Although the case series investigating VP/KP have all shown an outstanding analgesic benefit, randomized controlled studies are rare and have yielded contradictory results. In several of these studies, a short-term analgesic benefit was observed, except in the prospective randomized sham-controlled studies. A long-term analgesic and functional benefit has rarely been noted. Several recent studies have shown that both VP and KP are associated with an increased risk of new VFs. These fractures are mostly VFs adjacent to the procedure, and they occur within a shorter time period than VFs in other locations. The main risk factors include the number of preexisting VFs, the number of VPs/KPs performed, age, decreased bone mineral density, and intradiscal cement leakage. It is therefore important to involve the patients to whom VP/KP is being proposed in the decision-making process. It is also essential to rapidly initiate a specific osteoporosis therapy when a VF occurs (ideally a bone anabolic treatment) so as to reduce the risk of fracture. Randomized controlled studies are necessary in order to better define the profile of patients who likely benefit the most from VP/KP.

Comparison of vertebroplasty and kyphoplasty in the treatment of osteoporotic vertebral compression fractures with intravertebral clefts

BACKGROUND

Few studies have compared the surgical outcomes of vertebroplasty (VP) and kyphoplasty (KP) in the treatment of osteoporotic vertebral compression fractures (VCFs) with intravertebral clefts.

METHODS

A retrospective study was conducted to review patients with a single-level osteoporotic VCF treated by VP or KP. Intravertebral clefts were assessed by preoperative computed tomography (CT) and magnetic resonance scans. All enrolled patients were followed up for 12 months. Clinical outcomes, radiological findings and complications were evaluated.

RESULTS

A total of 53 patients were available for data analysis. Most of the fractures (75.5 %) occurred in the region of the thoracolumbar junction (T10-L2). Twenty-four patients received VP and 29 patients received KP. Patients in both group had significant pain relief after surgery (P < 0.01). Compared with VP group, there was a significant lower visual analogue scale (VAS) score in KP group at the 6- (P = 0.04) and 12-month follow-up (P = 0.02), but the decreased values of VAS score had no significant correlation with the magnitude of deformity correction. Restoration of vertebral body height and reduction in kyphotic angle were achieved in both groups, and the magnitude of correction was more significant in KP group (P < 0.01). Cement leakage rate in VP group (66.7 %) was higher than that in KP group (20.7 %), and there was a significant difference (P < 0.01).

CONCLUSIONS

Intravertebral clefts occur primarily at the thoracolumbar junction and can be detected easily by CT and magnetic resonance imaging scans. Both VP and KP are effective in the treatment of clefts, but patients in KP group tend to have a better pain relief at the medium and long-term follow-up. However, the better pain relief effect of KP cannot be attributed to the higher magnitude of deformity correction.

Intravertebral pressure gradient during vertebroplasty

OBJECTIVE

Intravertebral pressure (IP) is considered a possible factor influencing cement leakage in vertebroplasty (VP). Reports of measuring IP during the injection of the cement reveal rather low values in the periphery of the vertebral body but fail to determine the situation in the center. Hypothesizing there is a significant IP gradient between both areas intravertebral pressure measurements were conducted in a comparative biomechanical study.

METHODS

VP was performed in ten lumbar cadaveric spines. A pressure sensor was either placed in the center or in the periphery of the vertebral body, while bone cement was delivered in 1.5-cc increments. Volume flow, cement mixing time, and room temperature were standardized and kept constant during cement injection.

RESULTS

During the administration of the first 1.5 cc of bone cement, the central IP (C-IP) increased to 23.6 kPa and the peripheral IP (P-IP) to 0.9 kPa on average. With the second injection, the mean C-IP was 42.8 kPa while the mean P-IP was 3.8 kPa. During the 3rd filling, C-IP averaged 69.9 kPa and P-IP 12.8 kPa, respectively. At the last increment, C-IP was at 70.7 kPa and P-IP at 24.5 kPa on average.

CONCLUSIONS

A centroperipheral IP gradient (∆IP) was monitored during cement delivery in VP. ∆IP decreases with increasing bone cement charge of the vertebra, but C-IP stays significantly higher than P-IP at all times. C-IP was consistently higher than IP values reported for VP so far.

Hypothermic manipulation of bone cement can extend the handling time during vertebroplasty

Background

Polymethylmethacrylate (PMMA) is commonly used for clinical applications. However, the short handling time increases the probability of a surgeon missing the crucial period in which the cement maintains its ideal viscosity for a successful injection. The aim of this article was to illustrate the effects a reduction in temperature would have on the cement handling time during percutaneous vertebroplasty.

Methods

The injectability of bone cement was assessed using a cement compressor. By twisting the compressor, the piston transmits its axial load to the plunger, which then pumps the bone cement out. The experiments were categorized based on the different types of hypothermic manipulation that were used. In group I (room temperature, sham group), the syringes were kept at 22°C after mixing the bone cement. In group 2 (precooling the bone cement and the container), the PMMA powder and liquid, as well as the beaker, spatula, and syringe, were stored in the refrigerator (4°C) overnight before mixing. In group 3 (ice bath cooling), the syringes were immediately submerged in ice water after mixing the bone cement at room temperature.

Results

The average liquid time, paste time, and handling time were 5.1 ± 0.7, 3.4 ± 0.3, and 8.5 ± 0.8 min, respectively, for group 1; 9.4 ± 1.1, 5.8 ± 0.5, and 15.2 ± 1.2 min, respectively, for group 2; and 83.8 ± 5.2, 28.8 ± 6.9, and 112.5 ± 11.3 min, respectively, for group 3. The liquid and paste times could be increased through different cooling methods. In addition, the liquid time (i.e. waiting time) for ice bath cooling was longer than for that of the precooling method (p < 0.05).

Conclusions

Both precooling (i.e. lowering the initial temperature) and ice bath cooling (i.e. lowering the surrounding temperature) can effectively slow polymerization. Precooling is easy for clinical applications, while ice bath cooling might be more suitable for multiple-level vertebroplasty. Clinicians can take advantage of the improved injectability without any increased cost.

The early stage adjacent disc degeneration after percutaneous vertebroplasty and kyphoplasty in the treatment of osteoporotic VCFs

BACKGROUND

The purpose of this paper is to determine the early incidence of disc de- generation adjacent to the vertebral body of osteoporotic fracture treated with percutaneous vertebroplasty or balloon kyphoplasty and whether adjacent disc degeneration is accelerated by this two procedures.

METHODS

182 patients with painful vertebral compression fractures were treated. A total of 97 patients were enrolled in this prospective study. 97 patients with a mean age of 65.3 years were classified into control group and surgical treatment group of non-random. 35 patients were in control group and 62 patients who were performed percutaneous vertebroplasty or balloon kyphoplasty in treatment group. X-ray and Magnetic resonance imaging were done at the first and final visit. The grade of disc degeneration above the fractured vertebral was confirmed by evaluation of bony oedema in the fat suppressed sequences and T2-weighted image of magnetic resonance imaging. The height of degenerative disc was measured on X-ray film.

RESULTS

All patients were followed up two years after the first visit and the follow-up rate was 90.7% (88/97). The incidence of degeneration of adjacent disc above the fractured vertebral was 29.0% (9/31) in control group and 52.6% (30/57) in treatment group. It presented a statistically significant difference between two groups about the incidence of adjacent disc degeneration (P=0.033). The percentage of adjacent disc height reduction in control group was 13.5% and 17.6% in treatment group. Statistically significant difference of VAS score and ODI was not found between the first evaluation postoperatively and the final follow-up in treatment group (P>0.05).

CONCLUSIONS

Disc degeneration adjacent to the fractured vertebral is accelerated by VP and BK procedures in the early stage, but clinical outcomes has not been weakened even in the presence of accelerated disc degeneration.

Comparison of kyphoplasty and vertebroplasty for treatment of painful osteoporotic vertebral compression fractures: twelve-month follow-up in a prospective nonrandomized comparative study

STUDY DESIGN

A prospective nonrandomized comparative study.

OBJECTIVE

To compare the efficacy and safety of kyphoplasty and vertebroplasty for treatment of painful osteoporotic vertebral compression fractures (VCFs) with respect to pain, functional outcome, radiomorphology, cement leakage, and incidence of new adjacent vertebral fracture.

SUMMARY OF BACKGROUND DATA

Kyphoplasty and vertebroplasty have become common treatments for painful osteoporotic VCFs. Although the benefits of either kyphoplasty or vertebroplasty compared with conservative treatment have been frequently discussed, few clinical studies are available that directly compare the 2 procedures.

METHODS

Ninety-six patients with painful osteoporotic VCFs less than 4 weeks old were included and nonrandomly assigned to undergo kyphoplasty or vertebroplasty treatment. Clinical outcomes were assessed using the visual analog scale and the Oswestry Disability Index. Plain radiographs were analyzed to quantify spinal deformity correction (vertebral body height and kyphotic angle), and evaluate cement leakage and new adjacent vertebral fractures. The follow-up time was 12 months.

RESULTS

The baseline clinical and radiological characteristics of both groups were comparable. There were no significant differences between the 2 groups with regard to improvement in pain and functional scores at all postoperative intervals. Vertebral height restoration and kyphotic angle reduction were achieved in both groups, but the correction of spinal deformity was more significant in the kyphoplasty group. Asymptomatic cement leakage occurred in 9.1% and 34.6% of treated vertebrae for the kyphoplasty and vertebroplasty groups, respectively. Three adjacent fractures in the kyphoplasty group and 2 in the vertebroplasty group were identified during the follow-up time, and no major adverse events were observed.

CONCLUSIONS

Kyphoplasty and vertebroplasty demonstrated similar good clinical outcomes during the 12-month follow-up. Kyphoplasty offers a higher degree of spinal deformity correction and results in less cement leakage than vertebroplasty. The benefits of these relative merits need to be ascertained in future long-term studies.

Non-pharmacological management of osteoporosis: a consensus of the Belgian Bone Club

This consensus article reviews the various aspects of the non-pharmacological management of osteoporosis, including the effects of nutriments, physical exercise, lifestyle, fall prevention, and hip protectors. Vertebroplasty is also briefly reviewed. Non-pharmacological management of osteoporosis is a broad concept. It must be viewed as an essential part of the prevention of fractures from childhood through adulthood and the old age. The topic also includes surgical procedures for the treatment of peripheral and vertebral fractures and the post-fracture rehabilitation. The present document is the result of a consensus, based on a systematic review and a critical appraisal of the literature. Diets deficient in calcium, proteins or vitamin D impair skeletal integrity. The effect of other nutriments is less clear, although an excessive consumption of sodium, caffeine, or fibres exerts negative effects on calcium balance. The deleterious effects of tobacco, excessive alcohol consumption and a low BMI are well accepted. Physical activity is of primary importance to reach optimal peak bone mass but, if numerous studies have shown the beneficial effects of various types of exercise on bone mass, fracture data as an endpoint are scanty. Fall prevention strategies are especially efficient in the community setting, but less evidence is available about their effectiveness in preventing fall-related injuries and fractures. The efficacy of hip protectors remains controversial. This is also true for vertebroplasty and kyphoplasty. Several randomized controlled studies had reported a short-term advantage of vertebroplasty over medical treatment for pain relief, but these findings have been questioned by recent sham-controlled randomized clinical studies.

Correlative factor analysis on the complications resulting from cement leakage after percutaneous kyphoplasty in the treatment of osteoporotic vertebral compression fracture

STUDY DESIGN

The correlative factors for complications resulting from cement leakage were retrospectively reviewed in 71 patients who underwent percutaneous kyphoplasty.

OBJECTIVE

To explore the correlative factors affecting the complications of percutaneous kyphoplasty in the treatment of osteoporotic vertebral compression fractures.

SUMMARY OF BACKGROUND DATA

Over the past decade, percutaneous kyphoplasty has been increasingly used as treatment of choice for osteoporotic vertebral compression fractures. However, current literature contains less information about the correlative factors affecting the complications resulted from cement leakage.

METHODS

In all, 71 patients with 171 vertebral compression fractures who were treated by percutaneous kyphoplasty in the department of spine surgery at our medical center were identified from the registry and were retrospectively reviewed. The treatment efficacy was determined by the assessment of change in vertebral body height, Cobb angle, visual analog scale and Oswestry functional score between preoperative, postoperative, and the latest follow-up. Complications were recorded and associated risk factors were determined and analyzed.

RESULTS

All patients had immediate and significant improvement in back pain after being treated with percutaneous kyphoplasty. Cement leakage occurred in 17 (9.94%) out of 171 vertebral bodies, including 7 paravertebral leaks, 6 leaks into intervertebral space, 3 leaks into channel of needling insertion, and 1 spinal canal leak. Four patients (5.63%) developed pulmonary complications postoperatively, one of them with confirmed diagnosis of pulmonary embolism directly caused by cement leakage. During the follow-up, we found 9 recurrence vertebral fractures in 6 patients (8.45%), including 6 adjacent vertebral bodies. Univariate analysis revealed a significant difference in preoperative vertebral body height, injected cement volume, and vertebral body wall incompetence between the cement leakage group and no cement leakage group (P<0.05). In contrast, there is no significant difference in the preoperative Cobb angle, freshness of vertebral fracture, location of operative vertebrae, and operative approach between the 2 groups (P>0.05). Multiple logistic regression analysis showed that the injected cement volume and vertebral body wall incompetence were the predominant variables associated with the complications resulting from cement leakage. The patients who had a history of pulmonary diseases were prone to develop lung-related complications after the surgery.

CONCLUSIONS

The cement viscosity, injected cement volume, vertebral body wall incompetence, and a history of pulmonary diseases were the factors affecting the complications resulting from cement leakage. The recognition of these risk factors is helpful in efforts to improve surgical technique to reduce the risk of complications after being treated by percutaneous kyphoplasty.

Vertebroplasty and Kyphoplasty Can Restore Normal Spine Mechanics following Osteoporotic Vertebral Fracture

Osteoporotic vertebral fractures often lead to pain and disability. They can be successfully treated, and possibly prevented, by injecting cement into the vertebral body, a procedure known as vertebroplasty. Kyphoplasty is similar, except that an inflatable balloon is used to restore vertebral body height before cement is injected. These techniques are growing rapidly in popularity, and a great deal of recent research, reviewed in this paper, has examined their ability to restore normal mechanical function to fractured vertebrae. Fracture reduces the height and stiffness of a vertebral body, causing the spine to assume a kyphotic deformity, and transferring load bearing to the neural arch. Vertebroplasty and kyphoplasty are equally able to restore vertebral stiffness, and restore load sharing towards normal values, although kyphoplasty is better at restoring vertebral body height. Future research should optimise these techniques to individual patients in order to maximise their beneficial effects, while minimising the problems of cement leakage and adjacent level fracture.

Is kyphoplasty better than vertebroplasty in restoring normal mechanical function to an injured spine?

INTRODUCTION

Kyphoplasty is gaining in popularity as a treatment for painful osteoporotic vertebral body fracture. It has the potential to restore vertebral shape and reduce spinal deformity, but the actual clinical and mechanical benefits of kyphoplasty remain unclear. In a cadaveric study, we compare the ability of vertebroplasty and kyphoplasty to restore spine mechanical function, and vertebral body shape, following vertebral fracture.

METHODS

Fifteen pairs of thoracolumbar "motion segments" (two vertebrae with the intervening disc and ligaments) were obtained from cadavers aged 42-96 years. All specimens were compressed to induce vertebral body fracture. Then one of each pair underwent vertebroplasty and the other kyphoplasty, using 7 ml of polymethylmethacrylate cement. Augmented specimens were compressed for 2 hours to allow consolidation. At each stage of the experiment, motion segment stiffness was measured in bending and compression, and the distribution of loading on the vertebrae was determined by pulling a miniature pressure transducer through the intervertebral disc. Disc pressure measurements were performed in flexed and extended postures with a compressive load of 1.0-1.5 kN. They revealed the intradiscal pressure (IDP) which acts on the central vertebral body, and they enabled compressive load-bearing by the neural arch (F(N)) to be calculated. Changes in vertebral height and wedge angle were assessed from radiographs. The volume of leaked cement was determined by water displacement. Volumetric bone mineral density (BMD) of each vertebral body was calculated using DXA and water displacement.

RESULTS

Vertebral fracture reduced motion segment compressive stiffness by 55%, and bending stiffness by 39%. IDP fell by 61-88%, depending on posture. F(N) increased from 15% to 36% in flexion and from 30% to 58% in extension (P<0.001). Fracture reduced vertebral height by an average 0.94 mm and increased vertebral wedging by 0.95 degrees (P<0.001). Vertebroplasty and kyphoplasty were equally effective in partially restoring all aspects of mechanical function (including stiffness, IDP, and F(N)), but vertebral wedging was reduced only by kyphoplasty (P<0.05). Changes in mechanical function and vertebral wedging were largely maintained after consolidation, but height restoration was not. Cement leakage was similar for both treatments.

CONCLUSIONS

Vertebroplasty and kyphoplasty were equally effective at restoring mechanical function to an injured spine. Only kyphoplasty was able to reverse minor vertebral wedging.

Lumbar tumor resections and management

More than one-third of patients with cancer have vertebral metastases found at autopsy. Primary and metastatic tumors to the spinal column can lead to pain, instability, and neurologic deficit. Symptomatic lesions are most prevalent in the thoracic spine (70%), followed by the lumbar spine (20%) and cervical spine (10%). Lesions in larger vertebral bodies tend to be asymptomatic given the increased ratio between the diameter of the spinal canal and the traversing nerve roots.