Prophylactic vertebroplasty procedure applied with a resorbable bone cement can decrease the fracture risk of sandwich vertebrae: long-term evaluation of clinical outcomes

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

Objective

We analyzed the influence of the location of the upper and lower cement on the sandwich vertebrae (SV) by computer finite element analysis.

Materials and Methods

A finite element model of the spinal segment of T11-L1 was constructed and 6 mL of cement was built into T11 and L1 simultaneously. According to the various distributions of bone cement at T11 and L1, the following four groups were formed: (i) Group B-B: bilateral bone cement reinforcement in both T11 and L1 vertebral bodies; (ii) Group L-B: left unilateral reinforcement in T11 and bilateral reinforcement in L1; (iii) Group L-R: unilateral cement reinforcement in both T11 and L1 (cross); (iv) Group L-L: unilateral cement reinforcement in both T11 and L1 (ipsilateral side). The maximum von Mises stress (VMS) and maximum displacement of the SV and intervertebral discs were compared and analyzed.

Results

The maximum VMS of T12 was in the order of size: group B-B < L-B < L-R < L-L. Group B-B showed the lowest maximum VMS values for T12: 19.13, 18.86, 25.17, 25.01, 19.24, and 20.08 MPa in six directions of load flexion, extension, left and right lateral bending, and left and right rotation, respectively, while group L-L was the largest VMS in each group, with the maximum VMS in six directions of 21.55, 21.54, 30.17, 28.33, 19.88, and 25.27 MPa, respectively.

Conclusion

Compared with the uneven distribution of bone cement in the upper and lower adjacent vertebrae (ULAV), the uniform distribution of bone cement in the ULAV reduced and uniformed the stress load on the SV and intervertebral disc. Theoretically, it can lead to the lowest incidence of sandwich vertebral fracture and the slowest rate of intervertebral disc degeneration.

Are Sandwich Vertebrae Prone to Refracture After Percutaneous Vertebroplasty or Kyphoplasty? A Meta-Analysis

BACKGROUND

The formation of sandwiched vertebrae (SDVs) after percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) has become a common phenomenon. Whether SDVs are more likely to fracture is still controversial. Therefore, we conducted a meta-analysis to provide medical evidence for whether SDVs are more prone to refracture than non-SDVs (NSDVs) after PVP or PKP.

METHODS

This study was conducted in accordance with the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Several databases, including PubMed, Embase, Medline databases, China National Knowledge Infrastructure, Wanfang, and Weipu, were thoroughly searched for relevant studies included from any point up until June 2022. Statistical analyses were performed using Revman 5.4.

RESULTS

A total of 4052 individuals from 9 studies were enrolled. Overall, patients with SDV presented more risk to have refracture than patients with NSDV (OR = 1.57, P = 0.04). The incidences of refracture were comparable between the 2 cohorts in studies with a follow-up time less than 3 years (OR = 1.28, P = 0.49). However, patients with SDV were more prone to have refracture than patients with NSDV in studies with a follow-up time longer than 3 years (OR = 1.92, P = 0.009). Moreover, patients with SDV were more likely to have refracture than patients with NSDV in studies that involved both PVP and PKP (OR = 1.62, P = 0.002). In addition, age, low bone density, and postoperative kyphosis angle of sandwich fracture segments >10° were independent factors to predict refracture.

CONCLUSIONS

Patients with SDV were more likely to have refracture after PVP or PKP, especially when the follow-up time was longer than 3 years.

LEVEL OF EVIDENCE: 3

Biomechanical analysis of sandwich vertebrae in osteoporotic patients: finite element analysis

Objective

The aim of this study was to investigate the biomechanical stress of sandwich vertebrae (SVs) and common adjacent vertebrae in different degrees of spinal mobility in daily life.

Materials and methods

A finite element model of the spinal segment of T10-L2 was developed and validated. Simultaneously, T11 and L1 fractures were simulated, and a 6-ml bone cement was constructed in their center. Under the condition of applying a 500-N axial load to the upper surface of T10 and immobilizing the lower surface of L2, moments were applied to the upper surface of T10, T11, T12, L1, and L2 and divided into five groups: M-T10, M-T11, M-T12, M-L1, and M-L2. The maximum von Mises stress of T10, T12, and L2 in different groups was calculated and analyzed.

Results

The maximum von Mises stress of T10 in the M-T10 group was 30.68 MPa, 36.13 MPa, 34.27 MPa, 33.43 MPa, 26.86 MPa, and 27.70 MPa greater than the maximum stress value of T10 in the other groups in six directions of load flexion, extension, left and right lateral bending, and left and right rotation, respectively. The T12 stress value in the M-T12 group was 29.62 MPa, 32.63 MPa, 30.03 MPa, 31.25 MPa, 26.38 MPa, and 26.25 MPa greater than the T12 stress value in the other groups in six directions. The maximum stress of L2 in M-T12 in the M-L2 group was 25.48 MPa, 36.38 MPa, 31.99 MPa, 31.07 MPa, 30.36 MPa, and 32.07 MPa, which was greater than the stress value of L2 in the other groups. When the load is on which vertebral body, it is subjected to the greatest stress.

Conclusion

We found that SVs did not always experience the highest stress. The most stressed vertebrae vary with the degree of curvature of the spine. Patients should be encouraged to avoid the same spinal curvature posture for a long time in life and work or to wear a spinal brace for protection after surgery, which can avoid long-term overload on a specific spine and disrupt its blood supply, resulting in more severe loss of spinal quality and increasing the possibility of fractures.

Treatment of multisegmental vertebral compression, burst fractures, and sandwich vertebra with severe osteoporosis using the PKP technique: a case report and literature review

This study aimed to present a special case of treatment of a patient with multisegmental vertebral compression fracture, burst fracture, and sandwich vertebra and to review the literature on this condition. An 85 year-old female presented with severe low back pain but no radiating pain in the lower extremities. The patient was diagnosed with T12 and L5 vertebral compression fractures, fresh vertebral burst fractures in L2 and L3, and osteoporosis. The focus was on formulating a surgical treatment strategy. At the 12 month follow-up, no neurological deficits were observed, and the chosen surgical treatment approach yielded favorable clinical outcomes. A comprehensive literature review indicates that percutaneous kyphoplasty (PKP) can effectively alleviate pain and ensure safety in managing osteoporotic vertebral burst fractures. While complications remain a theoretical risk, they can be mitigated through meticulous assessment, careful surgical procedures, and appropriate preventive measures. PKP is an effective and safe treatment modality for osteoporotic vertebral burst fractures. Conservative management of sandwich vertebrae can yield positive clinical outcomes, but regular anti-osteoporosis treatment is necessary.

Core-Shell Structured Porous Calcium Phosphate Bioceramic Spheres for Enhanced Bone Regeneration

Adequate new bone regeneration in bone defects has always been a challenge as it requires excellent and efficient osteogenesis. Calcium phosphate (CaP) bioceramics, including hydroxyapatite (HA) and biphasic calcium phosphates (BCPs), have been extensively used in clinical bone defect filling due to their good osteoinductivity and biodegradability. Here, for the first time, we designed and fabricated two porous CaP bioceramic granules with core-shell structures, named in accordance with their composition as BCP@HA and HA@BCP (core@shell). The spherical shape and the porous structure of these granules were achieved by the calcium alginate gel molding technology combined with a H₂O₂ foaming process. These granules could be stacked to build a porous structure with a porosity of 65-70% and a micropore size distribution between 150 and 450 μm, which is reported to be good for new bone ingrowth. In vitro experiments confirmed that HA@BCP bioceramic granules could promote the proliferation and osteogenic ability when cocultured with bone marrow mesenchymal stem cells, while inhibiting the differentiation of RAW264.7 cells into osteoclasts. In vivo, 12 weeks of implantation in a critical-sized femoral bone defect animal model showed a higher bone volume fraction and bone mineral density in the HA@BCP group than in the BCP@HA or pure HA or BCP groups. From histological analysis, we discovered that the new bone tissue in the HA@BCP group was invading from the surface to the inside of the granules, and most of the bioceramic phase was replaced by the new bone. A higher degree of vascularization at the defect region repaired by HA@BCP was revealed by 3D microvascular perfusion angiography in terms of a higher vessel volume fraction. The current study demonstrated that the core-shell structured HA@BCP bioceramic granules could be a promising candidate for bone defect repair.

Is the incidence of sandwich vertebral fracture higher than that of ordinary adjacent vertebral fracture after PKP?

OBJECTIVE

To compare the incidence of fracture between sandwich vertebra and ordinary adjacent vertebra after percutaneous kyphoplasty (PKP).

METHOD

We analyzed 225 consecutive patients with osteoporotic vertebral compression fractures who underwent PKP between January 2016 and December 2020 at our medical institution. The sandwich vertebrae was located between 2 cement-augmented vertebra and was followed for at least 12 months. The clinical data of patients with sandwich vertebra and ordinary adjacent vertebra were recorded, and the incidence of postoperative fracture between sandwich vertebra and ordinary adjacent vertebra was compared.

RESULTS

The mean continuous follow-up time was 31.30 ± 18.04 months in patients with sandwich vertebra and 25.85 ± 7.96 months in patients with ordinary adjacent vertebra. It should be noted that the incidence of sandwich vertebral fractures was 10.00%, which was not statistically higher than 3.26% for ordinary adjacent vertebral fractures. However, a significant difference was observed in the cement volume of single vertebral body, procedure time, and bleeding.

CONCLUSION

Although the volume of cement in a single vertebral body is less and the procedure time and bleeding are more, the incidence of sandwich vertebral fracture is not higher than that of ordinary adjacent vertebral body.

AGN1 implant material to treat bone loss: Resorbable implant forms normal bone with and without alendronate in a canine critical size humeral defect model

BACKGROUND

Fractures secondary to osteoporosis, particularly those of the hip and spine, are a major public health concern with high social and economic costs. The Local Osteo-Enhancement Procedure (LOEP) is an approach intended to strengthen skeletal areas that are at the highest risk for fracture due to osteoporosis. LOEP involves the implantation of AGN1, a triphasic, calcium-based, osteoconductive material which is then resorbed and replaced by bone. Since alendronate is the most prescribed osteoporotic treatment, the purpose of this canine study is to determine if the newly formed bone has the same properties as normal bone and whether alendronate treatment impacts AGN1 resorption and replacement with bone.

METHODS

Sixty skeletally mature male hounds (24-38 kg) were evenly divided between alendronate (0.2 mg/kg/day) and non-alendronate treatment groups. A critical-size core bone defect created in one proximal humerus was implanted with AGN1 while the contralateral non-operated humerus served as a paired control in each animal. Animals were sacrificed 13, 26, and 52 weeks post-operatively (10 per treatment per timepoint). The control and treatment site bone specimens from each animal were examined using radiographic, histomorphometric, and biomechanical techniques. Results between alendronate-treated and non-alendronate-treated animals were compared as groups.

RESULTS

AGN1 implant material was consistently resorbed and replaced by bone in all animals. At 52 weeks, only minimal residual implant material could be detected (0.9 ± 2.3% non-alendronate group; 2.2 ± 3.1% alendronate group), and new bone filled the defects in both the non-alendronate and alendronate groups. At 13 and 26 weeks, microCT revealed the newly formed bone in the defects had significantly higher trabecular bone volume and number connectivity than control bone in both groups. Mechanical testing demonstrated that the new bone had ultimate compressive strength and modulus equivalent to control bone as early as 13 weeks post-surgery which was maintained to 52 weeks in both groups.

CONCLUSIONS

In this canine critical-sized humeral core defect model, AGN1 was progressively replaced by normal bone as evaluated by all outcome measures. Concurrent alendronate therapy did not significantly impact AGN1 resorption or new bone formation. These results demonstrate that AGN1 can be used in conjunction with alendronate in non-osteoporotic animals.

CLINICAL RELEVANCE

This study suggests that the AGN1 implant material demonstrates potential for local restoration of bone in critical-size core defects, and that the material is compatible with alendronate drug therapy. Further studies will be required to determine if these results apply to other osteoporosis medications.

Do sandwich vertebral bodies increase the risk of post-augmentation fractures? A retrospective cohort study

Until now, there have been only a few retrospective studies that focused on the outcomes of sandwich vertebral bodies (SVBs). This is a long-term retrospective cohort study to investigate the SVBs. We found that although patients with SVBs had a relatively high risk of developing new fractures after VA, the incidence rate of new fractures was not significantly different from that of the control group. However, the statistical power of this study was very limited. Therefore, and because the refracture rate in these patients is substantial, routine long-term monitoring of patients after VA for osteoporosis is strongly recommended.

BACKGROUND

Sandwich vertebral bodies (SVBs) are intact unaugmented vertebral bodies between two previously augmented vertebrae. Until recently, only a few studies have reported the outcomes and strategies for SVBs. This retrospective cohort study aimed to describe the clinical features and incidence of new fractures in patients with SVBs.

METHODS

The clinical data were collected from 179 patients with 237 symptomatic osteoporotic vertebral compression fractures who underwent vertebral augmentation (VA). Among them, 23 patients with 24 levels of SVBs were included. Spinal radiographs (X-ray and CT) of all patients were evaluated prior to surgery 1 day after primary VA and during follow-up.

RESULTS

All patients successfully underwent PKP with an average follow-up period of 21.48 months. Asymptomatic cement leakage occurred in four patients (17.4%), and eight patients (34.8%) developed new fractures following primary PKP, including four sandwich, six adjacent, four remote vertebral fractures, and one re-collapse of cemented vertebrae. The incidence of new fractures in the SVB and control groups was 16.7% (4/24) and 13.0% (6/46), respectively, but there was no significant difference.

CONCLUSIONS

Although patients with SVBs had a relatively high risk of developing new fractures after VA, the incidence rate of new fractures was not significantly different from that of the control group. However, the statistical power of this study was very limited. Therefore, and because the refracture rate in these patients is substantial, routine long-term monitoring of patients after VA for osteoporosis is strongly recommended.

[Comparison of refracture risk between sandwich vertebrae and ordinary adjacent vertebrae]

Objective

To compare the refracture risk between sandwich vertebrae and ordinary adjacent vertebrae, and to explore the risk factors related to refracture.

Methods

Retrospective analysis was performed on the data of patients who received percutaneous vertebral augmentation (PVA) and formed sandwich vertebrae between April 2015 and October 2019. Of them, 115 patients were enrolled in the study. There were 27 males and 88 females with an average age of 73.9 years (range, 53-89 years). Univariate analysis was performed to analyzed the patients' general data, vertebral augmentation related indexes, and sandwich vertebrae related indexes. Survival analysis was performed for all untreated vertebrae at T ₄-L ₅ of the included patients at the vertebra-specific level, and risk curves of refracture probability of untreated vertebrae between sandwich vertebrae and ordinary adjacent vertebrae were compared. Cox's proportional hazards regression model was used to analyze risk factors for refracture.

Results

The 115 patients were followed up 12.6-65.9 months (mean, 36.2 months). Thirty-seven refractures involving 51 vertebral bodies occurred in 31 patients. The refracture rate of 27.0% (31/115) in patients with sandwich vertebrae was significantly higher than that of 15.2% (187/1228) in all patients who received PVA during the same period ( χ ²=10.638, P=0.001). Univariate analysis results showed that there was a significant difference in the number of augmented vertebrae between patients with and without refractures ( Z=0.870, P=0.004). However, there was no significant difference in gender, age, body mass index, whether had clear causes of fracture, whether had dual energy X-ray absorptiometry testing, whether the sandwich vertebra generated through the same PVA, puncture method, method of PVA, number of PVA procedures, number of vertebrae with old fracture, whether complicated with spinal deformity, bone cement distribution, and kyphosis angle of sandwich vertebral area ( P>0.05). Among the 1 293 untreated vertebrae, there were 136 sandwich vertebrae and 286 ordinary adjacent vertebrae. The refracture rate of sandwich vertebrae was 11.3% which was higher than that of ordinary adjacent vertebrae (6.3%)( χ ²=4.668, P=0.031). The 1- and 5-year fracture-free probabilities were 0.90 and 0.87 for the sandwich vertebrae, and 0.95 and 0.93 for the ordinary adjacent vertebrae, respectively. There was a significant difference between the two risk curves of refracture ( χ ²=4.823, P=0.028). Cox's proportional hazards regression model analysis results showed that the sandwich vertebrae, thoracolumbar location, the number of the augmented vertebrae, and the unilateral puncture were significant risk factors for refracture ( P<0.05).

Conclusion

The sandwich vertebrae has a higher risk of refracture when compared with the ordinary adjacent vertebrae, and its 1- and 5-year fracture-free probabilities are lower than those of the ordinary adjacent vertebrae. However, the 5-year fracture-free probability of sandwich vertebrae is still 0.87, so prophylactic enhancement is not recommended for all sandwich vertebrae. In addition, the sandwich vertebrae, thoracolumbar location, the number of the augmented vertebrae, and the unilateral puncture were important risk factors for refracture.

Improved Anti-Washout Property of Calcium Sulfate/Tri-Calcium Phosphate Premixed Bone Substitute with Glycerin and Hydroxypropyl Methylcellulose

Calcium sulfate/calcium phosphate (CS-CP)-based bone substitutes have been developed in premixed putty for usage in clinical applications. However, it is difficult to completely stop the bleeding during an operation because premixed putty can come into contact with blood or body fluids leading to disintegration. Under certain conditions depending on particle size and morphology, collapsed (washed) particles can cause inflammation and delay bone healing. In this context, anti-washout premixed putty CS-CP was prepared by mixing glycerin with 1, 2, and 4 wt% of hydroxypropyl methylcellulose (HPMC), and the resultant anti-washout properties were evaluated. The results showed that more than 70% of the premixed putty without HPMC was disintegrated after being immersed into simulated body fluid (SBF) for 15 min. The results demonstrated that the more HPMC was contained in the premixed putty, the less disintegration occurred. We conclude that CS-CP pre-mixed putty with glycerin and HPMC is a potential bone substitute that has good anti-washout properties for clinical applications.

Does prophylactic vertebral augmentation reduce the refracture rate in osteoporotic vertebral fracture patients: a meta-analysis

PURPOSE

In order to prevent the recurrent fracture after vertebral augmentation, the concept of prophylactic vertebral augmentation has been proposed, but its efficacy is still controversial. This study aimed to determine the efficacy of prophylactic vertebral augmentation for prevention of refracture in osteoporotic vertebral fracture patients.

METHODS

Following PRISMA guidelines, a literature search was performed using PubMed, Embase and Web of Science databases for relevant studies published until February 2021. A meta-analysis of randomized controlled trials and retrospective controlled trials comparing prophylactic group versus nonprophylactic group was conducted. The primary outcome was the incidence of new vertebral compression fracture (VCF), and secondary outcomes were incidence of adjacent vertebral fracture (AVF) and remote vertebral fracture (RVF).

RESULTS

A total of 6 studies encompassing 618 patients were included in the meta-analysis. The incidence of new VCF was reported in all six studies, and the result showed no significant difference between the two groups (OR: 0.509; 95% CI: 0.184-1.409). Four studies provided data on the incidence of AVF, and it was revealed that there was no significant difference between the two groups (OR: 0.689; 95% CI: 0.109-4.371). In view of the incidence of RVF, prophylactic group also did not differ significantly compared with nonprophylactic group (OR: 0.535; 95% CI: 0.167-1.709).

CONCLUSIONS

The current evidence suggested that prophylactic vertebral augmentation might not be appropriate to diminish the risk of new VCF. Therefore, there is a need to investigate the mechanism of refracture and explore other preventive regimens to reduce the risk.

Stentoplasty with Resorbable Calcium Salt Bone Void Fillers for the Treatment of Vertebral Compression Fracture: Evaluation After 3 Years

Purpose

The aim of the study is to investigate the clinical and radiological outcomes of vertebral compression fractures treated by stentoplasty with resorbable calcium salt bone void fillers compared with balloon kyphoplasty (BKP).

Methods

This prospective study included patients with fresh mono-thoracolumbar vertebral compression fractures. Patients enrolled were randomly divided into three groups. The patients in group A underwent stentoplasty with calcium sulfate/calcium phosphate (CSCP) composite filler and patients in group B with hydroxyapatite/collagen (HAP/COL) composite filler, while patients in group C underwent BKP with polymethylmethacrylate (PMMA). The clinical outcome was evaluated with visual analogue pain scale (VAS) and Oswestry disability score (ODI). The radiological results were evaluated with anterior height (AH) and Cobb angle of vertebral body. Computed tomography (CT) was used to assess osteogenesis effect.

Results

Each group included 14 patients. The VAS, ODI, Cobb angle and AH were statistically improved compared with preoperative and there was no significant difference between the three groups. However, the AH in group A and group B at 1-year follow-up presented slight loss compared with 1 day after surgery. CT results suggested both group A and group B presented obvious bone trabecula formation and variations of CT value.

Conclusion

The stentoplasty with resorbable calcium salt bone void fillers demonstrated clinical outcomes similar to traditional BKP for vertebral compression fractures. Both HAP/COL and CSCP performed certain osteogenesis. However, stentoplasty with studied fillers showed slight loss of AH within 1 year after surgery.

Fracture-free probability and predictors of new symptomatic fractures in sandwich, ordinary-adjacent, and non-adjacent vertebrae: a vertebra-specific survival analysis

BACKGROUND

It is unclear whether the sandwich vertebra, is at higher risk of new symptomatic fractures (NSFs), and whether prophylactic augmentation might benefit patients with sandwich vertebrae.

OBJECTIVE

To compare fracture-free probabilities of sandwich, ordinary-adjacent, and non-adjacent vertebrae, and identify predictors of NSFs.

METHODS

Data were retrospectively analyzed for patients who had undergone vertebral augmentation resulting in sandwich vertebrae. NSF rates were determined and predictors were identified using Cox proportional hazard models.

RESULTS

The analysis included 1408 untreated vertebrae (147 sandwich, 307 ordinary-adjacent, 954 non-adjacent vertebrae) in 125 patients. NSFs involved 19 sandwich, 19 ordinary-adjacent, and 16 non-adjacent vertebrae. The NSF rate was significantly higher in the patients with sandwich vertebrae (27.2%) than among all patients (14.8%). At the vertebra-specific level, the NSFs rate was 12.9% for sandwich vertebrae, significantly higher than 6.2% for ordinary-adjacent and 1.7% for non-adjacent vertebrae. The corresponding fracture-free probabilities of sandwich, ordinary-adjacent, and non-adjacent vertebrae were 0.89, 0.95, and 0.99 at 1 year, and 0.85, 0.92, and 0.98 at 5 years (p<0.05). Cox modeling identified the following as predictors for occurrence of an NSF in a given vertebra: vertebra location, type of vertebrae, number of augmented vertebrae, and puncture method.

CONCLUSION

Sandwich vertebrae are at higher risk of NSFs than ordinary-adjacent and non-adjacent vertebrae, and several NSF risk factors were identified. Since 85% of sandwich vertebrae are fracture-free for 5 years and NSF risk increases with the number of augmented vertebrae, prophylactic augmentation of every sandwich vertebra may be unnecessary.

The effect of bone cement distribution on the outcome of percutaneous Vertebroplasty: a case cohort study

Background

To analyze the effect of different types of bone cement distribution after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fracture (OVCF).

Methods

One hundred thirty seven patients with single level OVCF who underwent PVP were retrospectively analyzed. The patients were divided into two groups according to bone cement distribution. Group A: bone cement contacted both upper and lower endplates; Group B: bone cement missed at least one endplate. Group B was divided into 3 subgroups. Group B1: bone cement only contacted the upper endplates; Group B2: bone cement only contacted the lower endplates; Group B3: bone cement only located in the middle of vertebral body. The visual analogue scale (VAS) score at 24 h post operation and last follow-up, anterior vertebral height restoration ratio (AVHRR), anterior vertebral height loss ratio (AVHLR), local kyphotic angle change and vertebral body recompression rate were compared.

Results

24 h post operation, the pain of all groups were significantly improved. The average follow-up time was 15.3 ± 6.3 (6–24) months. At last follow-up, the VAS score of group A was lower than that of group B. There were 14 cases (10.2%) of adjacent vertebral fracture, 5 cases (8.6%) in group A and 9 cases (11.4%) in group B. There were 9 cases (6.6%) of cement leakage, 4 cases (6.9%) in group A and 5 cases (6.3%) in group B. At last follow-up, there were 16 cases (11.7%) of vertebral body recompression, including 3 cases (5.2%) in group A and 13 cases (16.5%) in group B. There was no significant difference in AVHRR between two groups. Local kyphotic angle change was significant larger in group B. At last follow-up, AVHLR in group B was higher than that in group A. Analysis in subgroup B revealed no significant difference in VAS score, local kyphotic angle change, vertebral recompression rate, AVHRR or AVHLR.

Conclusions

If the bone cement fully contacted both the upper and lower endplates, it can better restore the strength of the vertebral body and maintain the height of the vertebral body, reduce the risk of the vertebral body recompression and long-term pain.

Local osteo-enhancement of osteoporotic vertebra with a triphasic bone implant material increases strength-a biomechanical study

PURPOSE

The aim of this study was to assess the biomechanical properties of intact vertebra augmented using a local osteo-enhancement procedure to inject a triphasic calcium sulfate/calcium phosphate implant material.

METHODS

Twenty-one fresh frozen human cadaver vertebra (Th11-L2) were randomized into three groups: treatment, sham, and control (n = 7 each). Treatment included vertebral body access, saline lavage to displace soft tissue and marrow elements, and injection of the implant material to fill approximately 20% of the vertebral body by volume. The sham group included all treatment steps, but without injection of the implant material. The control group consisted of untreated intact osteoporotic vertebra. Load at failure and displacement at failure for each of the three groups were measured in axial compression loading.

RESULTS

The mean failure load of treated vertebra (4118 N) was significantly higher than either control (2841 N) or sham (2186 N) vertebra (p < 0.05 for: treatment vs. control, treatment vs. sham). Treated vertebra (1.11 mm) showed a significantly higher mean displacement at failure than sham vertebra (0.80 mm) (p < 0.05 for: treatment vs. sham). In the control group, the mean displacement at failure was 0.99 mm.

CONCLUSIONS

This biomechanical study shows that a local osteo-enhancement procedure using a triphasic implant material significantly increases the load at failure and displacement at failure in cadaveric osteoporotic vertebra.

Healing of osteoporotic bone defects by micro-/nano-structured calcium phosphate bioceramics

The micro-/nano-structured calcium phosphate bioceramic exhibited a higher new bone substitution rate in an osteoporotic bone defect rat model.