Elasticity and cross-sectional thickness of paraspinal muscles in progressive adolescent idiopathic scoliosis.

Objectives: (1) Compare the cross-sectional thickness (CST) and shear wave speed (SWS) of paraspinal muscles (PSM) in adolescent idiopathic scoliosis (AIS) with and without curve progression; (2) investigate the relationship between CST/SWS and radiographic characteristics in AIS with curve progression; (3) compare the CST/SWS between AIS and non-scoliosis controls. Methods: This cross-sectional study analyzed the CST and SWS of PSM in 48 AIS with mild to moderate curvature and 24 non-scoliosis participants. Participants with scoliosis greater than 45° of Cobb angles were excluded. The Change of Cobb angles within the last 6-months was retrieved to allocate AIS into progression and non-progression groups. The SWS and CST of multifidus; longissimus and iliocostalis of the major curve were measured using B-mode ultrasound image with an elastography mode. Discrepancies of the SWS (SWS-ratio: SWS on the convex side divided by SWS on the concave side) and CST (CST-ratio: CST on the convex side divided by CST on the concave side) at the upper/lower end and apical vertebrae were studied. Results: A higher SWS at the apical vertebrae on the concave side of the major curve (multifidus: 3.9 ± 1.0 m/s vs. 3.1 ± 0.6 m/s; p < 0.01, longissimus: 3.3 ± 1.0 m/s vs. 3.0 ± 0.9 m/s; p < 0.01, iliocostalis: 2.8 ± 1.0 m/s vs. 2.5 ± 0.8 m/s; p < 0.01) was observed in AIS with curve progression. A lower SWS-ratio at apical vertebrae was detected with a greater vertebral rotation in participants with curve progression (multifidus [grade II]: 0.7 ± 0.1 vs. grade I: 0.9 ± 0.2; p = 0.03, longissimus [grade II]: 0.8 ± 0.2 vs. grade I: 1.1 ± 0.2; p < 0.01). CST was not different among the progressive, non-progressive AIS and non-scoliosis controls. Conclusions: Increased SWS of PSM without change of CST was observed on the concave side of the major curve in participants with progressive AIS.

Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic Scoliosis.

STUDY DESIGN: This study adopted a prospective cohort study design. PURPOSE: This study aimed to examine electromyogram (EMG) discrepancy in paravertebral muscle activity and scoliosis progression, determine how vertebral morphology and EMG discrepancy evolve during scoliosis progression, and identify differences in EMG activity between individuals with and without adolescent idiopathic scoliosis (AIS). OVERVIEW OF LITERATURE: Higher EMG activity is observed in the convex side of scoliotic curves, but not in populations without scoliosis, suggesting that higher EMG activity is a causative factor for curve progression. METHODS: In this study, 267 matched pairs of AIS and controls were recruited. The participants underwent EMG measurements at their first presentation and did not receive any treatment for 6 months at which point they underwent EMG and radiographs. Early curve progression was defined as >5° in Cobb angle at 6 months. The root mean square of the EMG (rms-EMG) signal was recorded with the participants in sitting and back extension. The rms-EMG ratio at the upper end vertebrae, apical vertebrae (AV), and lower end vertebrae (LEV) of the major curve was calculated. RESULTS: The rms-EMG ratio in the scoliosis cohort was high compared with that in the controls (sitting: 1.2±0.3 vs. 1.0±0.1, p<0.01; back extension: 1.1±0.2 vs. 1.0±0.1, p<0.01). An AV rms-EMG ratio in back extension, with a cutoff threshold of ≥1.5 in the major thoracic curve and ≥1.3 in the major lumbar curve, was a risk factor for early curve progression after 6 months without treatment (odds ratio, 4.1; 95% confidence interval, 2.8-5.9; p<0.01). Increases in side deviation (SD) (distance between the AV and the central sacral line) were related to a higher rms-EMG ratio in LEV of the major thoracic curve (baseline: rs=0.2, p=0.03; 6 months: rs=0.3, p<0.01). CONCLUSIONS: An EMG discrepancy was detected in the scoliosis cohort, which was related to increases in SD in the major thoracic curve. The AV rms-EMG ratio in back extension was correlated with curve progression after 6 months of no treatment.

A solitary osteolytic lesion with pathological fracture in the cervical spine - a case report.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disorder. The treatment options vary depending on how many organs are involved and how extensive the disease is. In this report, a case of LCH with isolated 6th cervical vertebra (C6) collapse was presented. This case was treated with anterior corpectomy and instrumented fusion, followed by local radiotherapy (RT), with a good clinical outcome up to postoperative six months. CASE PRESENTATION: This was a 47-year-old female patient with a complaint of neck pain and bilateral shoulder pain for two months before consultation. She was initially treated with analgesics, but the pain was persistent. Further radiological evaluations revealed an osteolytic lesion within the C6 vertebral body with a pathological fracture. Magnetic resonance imaging (MRI) with contrast of the cervical spine revealed diffused hypointense signal changes on the T1-weighted images and hyperintense signal changes on the T2-weighted images in the C6 vertebral body, with significant contrast-enhanced infiltration signals. Furthermore, in positron emission tomography-computed tomography (PET-CT), focal hypermetabolism and abnormal uptake signals were seen only in the C6 vertebral body. The patient underwent an anterior cervical corpectomy with instrumented fusion. The histopathological results confirmed the diagnosis of LCH. The patient reported significant pain relief on postoperative day one. Moreover, she was treated by local RT at postoperative one month. Good clinical outcomes were achieved in the form of no pain and recovery in neck mobility up to postoperative six months. No evidence of recurrence was observed at the final follow-up. CONCLUSIONS: This case report describes a treatment option for a solitary C6 collapse with LCH managed by anterior corpectomy and instrumented fusion, followed by local RT, with a good clinical outcome at postoperative six months. More studies are needed to elucidate whether such a treatment strategy is superior to surgery or RT alone.

microRNA-145-5p inhibits prostate cancer bone metastatic by modulating the epithelial-mesenchymal transition.

Objective: To investigate the effects of miRNA-145-5p on the tumor development and progression of prostate cancer (Pca) bone metastasis. Methods: Levels of miRNA-145-5p were assessed by real-time quantitative PCR in PC3 (bone metastatic Pca cells), 22RV1 (non-metastatic Pca cells), RWPE-1 (non-cancerous prostate epithelial cells) and Pca tissues collected from patients with and without bone metastases. The impact of miRNA-145-5p on cell proliferation was tested by CCK8 assay, colony formation assay and flow cytometric cell cycle analysis. Effects on invasion and migration of PC3 cells were determined by Transwell and wound healing assays. Western blotting, enzyme-linked immunosorbent assay, and flow cytometry apoptosis analyses were also performed to assess roles in metastasis. Results: Levels of miRNA-145-5p were decreased in Pca bone metastases and miRNA-145-5p inhibited cell proliferation, migration and invasion. miRNA-145-5p inhibited the expression of basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF) and transforming growth factor-ß (TGF-ß) in PC3 cells. miR-145-5p increased the expression of the epithelial marker E-cadherin and reduced the expression of matrix metalloproteinase 2 and 9 (MMP-2 and MMP-9). It was found that miRNA-145-5p mediated the epithelial-mesenchymal transition (EMT) and induced apoptosis. Conclusions: miRNA-145-5p negatively regulated the EMT, inhibited Pca bone metastasis and promoted apoptosis in Pca bone metastasis. Mimicry of miRNA-145-5p action raises the possibility of a novel target for treating Pca with bone metastases.

The Relationship Between Compliance of Physiotherapeutic Scoliosis Specific Exercises and Curve Regression With Mild to Moderate Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective Case-control Study. OBJECTIVES: To determine the requisite exercise compliance (EC) of physiotherapeutic scoliosis-specific exercise (PSSE) for achieving curve regression; to analyze whether the apical translation (AT), apical wedging (AW), and apical rotation (AR) of the major curve improve with regression effect. METHODS: Between 2019 and 2021, a total of 763 patients undertook a 6-month PSSE treatment. This resulted 426 compliable and 302 uncompliable patients remained available for analysis. For compliable patients, 213 with curve regression and 213 age-/sex-matched with curve stabilization/deterioration at the 6-month, were eligible for regression analysis to detect the relationship between EC and regression effect at the 6-month; receiver operating characteristic (ROC) curve analysis and Youden's index were applied to identify the threshold of EC leading to curve regression at the 6-month. The AT, AW, and AR of the major curve were compared before and after 6-month PSSE to investigate the radiographic parameters that improved with regression effect. RESULTS: EC was correlated with regression effect (odds ratio: 19.9, 95% confidence interval: 11.3-35.0, P < .001) and the cutoff threshold of EC was 4.4 h/week for 6 months to realize such an effect. AT was improved by 47.6% with curve regression, in which 152 cases remained curve regression and no case progressed into the operative threshold at the 1.5- to 2-year. CONCLUSIONS: A 6-month PSSE protocol of 4.4 hours per week was potentially leading to curve regression in treating mild to moderate scoliosis. An improvement in AT of the major curve was observed with the regression effect.

Exosome-Derived miRNAs as Potential Biomarkers for Prostate Bone Metastasis.

Purpose: The purpose of this study was to identify the potential exosome-derived microRNAs (miRNAs) related to prostate cancer (Pca) bone metastasis. Methods: Two datasets were collected. One dataset was from the authors' institute, for which two groups of 10 patients each were designed: in the first one, the patients had early-stage localised Pca without bone metastasis, and in the other, the patients presented with Pca with bone metastasis. Then, the miRNA expression profiles of the blood exosomes were obtained and analysed. The other dataset was a public dataset of the miRNA expression transcriptome (GSE26964), which was downloaded from Gene Expression Omnibus (GEO). The results of both datasets were jointly analysed and the most bone-metastatic-related differentially expressed miRNAs (diff-miRNAs) were identified and further validated. Finally, a series of bioinformatics analyses were performed and the relationship between target genes of the diff-miRNAs and the pathogenesis and progression of bone metastasis of Pca were studied. Results: From the authors' dataset, in all, 313 diff-miRNAs were identified, of which 205 were up-regulated while 108 were down-regulated. From the GSE26964 dataset, 107 diff-miRNAs were found, of which 44 were up-regulated and 63 were down-regulated. Taking the intersection of the results of both datasets, four diff-miRNAs were identified: hsa-miR-125a-3p, hsa-miR-330-3p, hsa-miR-339-5p and hsa-miR-613. In all, 94 target genes of the four diff-miRNAs were predicted. After considering the intersection of the results from the GSE32269 dataset, we obtained 25 target genes. Although either positive or negative correlations were found among the diff-miRNAs with some of the target genes, there is a lack of evidence on how such correlations regulate the development and promotion of Pca bone metastasis. Conclusion: Hsa-miR-125a-3p, hsa-miR-330-3p, hsa-miR-339-5p and hsa-miR-613 are potential biomarkers for Pca bone metastasis.

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

INTRODUCTION: The purpose of this study was to test whether local filling of a novel strontium-containing hydroxyapatite (Sr-HA) bone cement can augment the fixation of a locking plate system in a cadaveric proximal humeral facture model. MATERIALS AND METHODS: Twelve pairs of formalin-treated cadaveric humeri were used. One side in each pair was for cemented group, while the other side was for the control group. The bone mineral density (BMD) of the samples was tested. A 3-part facture model was created and then reduced and fixed by a locking plate system. In the cemented group, the most proximal 4 screw holes were filled with 0.5 mL bone cement. In the control group, the screw holes were not filled by cement. Locking screws were inserted in a standard manner before the cement hardened. X-ray was taken before all the specimens being subjected to mechanical study, in which 6 pairs were used for axial loading (varus bending) test, while other 6 pairs were used for axial rotational test. RESULTS: There is no difference in BMD between the cemented side and the control side. The X-ray shows that the implant is in position. Cement filling was noted in the most proximal 4 screws in the cemented group. Better mechanical outcome was seen in the cemented groups, in terms of less maximal displacement per cycle and higher failure point and stiffness in varus bending test. However, no difference was found between the cemented group and the control group in the axial rotation test. DISCUSSION: In similarity with the previous studies, our results showed better mechanical results in the cemented group. However, due to the limitations (e.g. sample size, fracture model, testing protocol, etc), we still cannot directly extrapolate current mechanical results to clinical practice at the present moment. Furthermore, it is still unknown whether better primary outcome may lead to better long-term results, even though the local release of strontium may enhance the local bone formation. CONCLUSION: The local filling of Sr-HA bone cement augments the fixation of the locking plate system in current proximal humeral fracture model.

Strontium exerts dual effects on calcium phosphate cement: Accelerating the degradation and enhancing the osteoconductivity both in vitro and in vivo.

Calcium phosphate cements (CPCs) have long been used as osteoconductive bone substitutes in the treatment of bone defects. However, the degradation rate of CPC is typically too slow to match the new bone growth rate. It is known that strontium increases the solubility of hydroxyapatite as well as exerts both anabolic and anticatabolic effects on bone. Therefore, we hypothesized that the incorporation of strontium would accelerate the degradation rate and enhance the osteoconductivity of CPC. In this study, Three groups, CPC (0% Sr-CPC), 5% Sr-CPC, and 10% Sr-CPC, were prepared, with the total molar ratio for Sr/(Sr+Ca) in the cement powder phase being 0, 5, and 10%, respectively. In the immersion test, less residual weight was observed in both 5% Sr-CPC and 10% Sr-CPC groups than CPC group. In addition, a higher osteoblastic cell proliferation rate and alkaline phosphatase activity were obtained in the strontium groups. In a rat femur bone defect model comparing CPC with 10% Sr-CPC, at 2 weeks postoperation, early endochondral ossification was found in the 10% Sr-CPC group, whereas only fibrous tissue was observed in control group; at 4-16 weeks postoperation, progressive osteoconduction toward the cement was observed in both groups. At 32 weeks, a higher peri-cement bone area and reduced cement area were noted in the 10% Sr-CPC group. In conclusion, in the 10% Sr-CPC group, strontium exerts dual effects on CPC: accelerating degradation rate and enhancing osteoconductivity, as shown here both in vitro and in vivo.

Local application of strontium in a calcium phosphate cement system accelerates healing of soft tissue tendon grafts in anterior cruciate ligament reconstruction: experiment using a rabbit model.

BACKGROUND: Healing of soft tissue tendon grafts within the bone tunnel in anterior cruciate ligament (ACL) reconstruction is known to be slower than that of bone-patellar tendon-bone grafts. There are attempts to accelerate healing of the graft within the bone tunnel. One of the methods is the use of strontium-enriched calcium phosphate cement (Sr-CPC). Early results in animal studies have been encouraging, although it is not known whether the accelerated healing was solely caused by the effect of strontium within the cement or by the calcium phosphate cement (CPC) itself. HYPOTHESIS: There would be differences between Sr-CPC and conventional CPC in terms of the effect on healing of soft tissue tendon grafts within the bone tunnels in ACL reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 30 single-bundle ACL reconstruction procedures were performed in 15 rabbits with the use of an Achilles tendon allograft. The graft on the left limb was coated with Sr-CPC, while that on the right limb was coated with CPC. Three animals each were sacrificed for histological and histomorphometric analyses at 3, 6, 9, 12, and 24 weeks after surgery. RESULTS: In the Sr-CPC group, early formation of Sharpey fibers was present at 6 weeks after surgery, while early remodeling of a graft-fibrocartilage-bone junction was noted at 12 weeks. In the CPC group, early formation of Sharpey fibers was only found at 9 to 12 weeks after surgery. At 24 weeks, a direct enthesis was found in both groups. According to the histomorphometric score, graft healing in the Sr-CPC group took place 3 weeks faster than that in the CPC group at and before 12 weeks; however, there was no difference between the groups at 24 weeks. CONCLUSION: The local application of strontium in a CPC system leads to accelerated graft healing within the bone tunnels. CLINICAL RELEVANCE: The use of Sr-CPC to enhance graft-bone healing may improve the clinical results of ACL reconstruction using soft tissue tendon grafts.

Femoral radiographic landmarks for popliteus tendon reconstruction and repair: a new method of reference.

BACKGROUND: Although the popliteus muscle-tendon complex is one of the most important structures in controlling posterolateral rotatory stability of the knee, not much literature has been reported concerning the use of femoral radiographic landmarks of the popliteus tendon in repair and reconstruction. HYPOTHESIS: By using standardized radiographic techniques, the femoral insertion of the popliteus tendon could be more precisely determined by the Blumensaat line than by the extension line of the posterior cortex. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten fresh-frozen human knees were dissected, and the popliteus tendon was exposed. After identification of the femoral insertion site of the popliteus tendon, the insertion's center was indicated with a radiographic marker. True lateral radiographs of the distal femur were taken, and the digital radiographic images were analyzed by 2 independent observers. RESULTS: The femoral insertion site of the popliteus tendon was found to be a mean 47.5% ± 5.2% across the width of the femoral condyle, 60.7% ± 7.8% along the perpendicular bisector of the Blumensaat line, 0.3 ± 1.7 mm posterior to the extension line of the posterior femoral cortex, and 20.5 ± 3.8 mm distal to the perpendicular line at the Blumensaat point. The variance from the mean point by using the Blumensaat line as a reference was significantly smaller than by using the extension line of the posterior cortex (mean, 2.6 vs 3.6 mm; P = .044). CONCLUSION: A reproducible anatomic and radiographic reference point for the femoral insertion of the popliteus tendon can be determined using standardized radiographic techniques and can be more precisely determined by the Blumensaat line compared with the extension line of the posterior femoral cortex. CLINICAL RELEVANCE: This radiographic information provides an adjunctive tool for preoperative, intraoperative, and postoperative assessments of surgical repair and reconstruction of the popliteus tendon.

An effective approach by a chelate reaction in optimizing the setting process of strontium-incorporated calcium phosphate bone cement.

Strontium (Sr) plays a special role in enhancing the biological osteo-stimulation of calcium phosphate cement (CPC), not only increasing osteoblast-related gene expression and the alkaline phosphatase (ALP) activity of mesenchymal stem cells (MSCs), but also inhibiting the differentiation of osteoclasts. However, the incorporation of Sr unfortunately delays the setting of CPC and weakens its mechanical properties. The purpose of this study was to overcome the aforementioned problems by introducing a chelate reaction between Ca/Sr cations from the original solid phases and carboxyl groups from the liquid phases. As expected, the setting process of Sr-incorporated CPC was optimized and the cement body after rapid hardening was mostly consisting of unreacted original solid phases. After soaking in simulated body fluid for 14 and 28 days, the composition of the cement body gradually converted to the most thermodynamic stable phase, hydroxyapatite, indicating an in vitro bioactivity. The compressive strength was not impaired in the Sr-incorporated groups, but rather, further increased over time. Higher cell proliferation rate and better ALP activity of MG-63 cells cultured on the cement surface were obtained with the presence of Sr content, demonstrating potential abilities to favor new bone formation.

Osteointegration of soft tissue grafts within the bone tunnels in anterior cruciate ligament reconstruction can be enhanced.

Anterior cruciate ligament reconstruction with a soft tissue autograft (hamstring autograft) has grown in popularity in the last 10 years. However, the issues of a relatively long healing time and an inferior histological healing result in terms of Sharpey-like fibers connection in soft tissue grafts are still unsolved. To obtain a promising outcome in the long run, prompt osteointegration of the tendon graft within the bone tunnel is essential. In recent decades, numerous methods have been reported to enhance osteointegration of soft tissue graft in the bone tunnel. In this article, we review the current literature in this research area, mainly focusing on strategies applied to the local bone tunnel environment. Biological strategies such as stem cell and gene transfer technology, as well as the local application of specific growth factors have been reported to yield exciting results. The use of biological bone substitute and physical stimulation also obtained promising results. Artificially engineered tissue has promise as a solution to the problem of donor site morbidity. Despite these encouraging results, the current available evidence is still experimental. Further clinical studies in terms of randomized control trial in the future should be conducted to extrapolate these basic science study findings into clinical practice.

[Experimental study on spinal fusion induced by hBMP-4 gene modified tissue engineered bone].

OBJECTIVE: To evaluate the efficacy of hBMP-4 gene modified tissue engineered bone graft in the enhancement of rabbit spinal fusion and find an ideal kind of substitute for the autograft bone. METHODS: Rabbit BMSCs were cultured and transfected with AAV-hBMP-4 using different MOI value. The optimal MOI value were determined by observing cell's morphology change. BMSCs were then transfected with AAV-hBMP4 and AAV-EGFP respectively, following which the transfected cells were evenly suspended in a collagen sponge I, and implanted to either side of the L5,6 intertransverse spaces posterolateral in the New Zealand rabbits to induce spinal fusion. Fourteen rabbits were randomly divided into 2 groups. Group 1: AAV-hBMP-4 transfected BMSCs in the right side (hBMP-4 side) and autograft bone in the left side. Group 2: AAV-hBMP-4 transfected BMSCs in the right side (hBMP-4 side) and AAV-EGFP transfected BMSCs in the left side (EGFP side). Radiographs and three-dimensional CT of the spine, manual palpation, gross and histological examination of the fusion masses for all the animals were performed subsequent to animals having been sacrificed at 12 weeks after surgery. RESULTS: Evaluation has been taken in 12 New Zealand rabbits delivered into 2 groups which meet the criterion after operation. Eleven in 12 implemented sides involved hBMP-4 achieved bony fusion, to which 5 in 6 autografted sides was similar. But only 2 in 6 sides in EGFP-group achieved bony fusion meanwhile. Three-dimensional CT scan and palpation also evidenced the results. Bone formation was observed obviously on specimen both in hBMP4 sides and autografted ones. EGFP-group also got bony integration, but the quantity was small. CONCLUSION: Tissue-engineered bone graft constructed from application of hBMP4 is a fine substitute for autograft. Effective enhancement of bony integration in spinal fusion surgery has been evidenced in vivo.

[One-stage single balloon multiple expansions percutaneous kyphoplasty: report of 18 cases].

OBJECTIVE: To observe the effect and safety of one-stage single balloon multiple expansions percutaneous kyphoplasty (PKP) in treatment of osteoporotic vertebral compressive fracture (OVCF) and spinal tumor. METHODS: One-stage single balloon multiple expansions PKP was performed on 18 patients, 5 males and 13 females, aged 68.77 (44 - 80), with 45 vertebrae, including 11 case of OVCF (with 29 diseased vertebrae), 11 cases of multiple vertebral fracture (with 19 diseased vertebrae), 5 cases of multiple myeloma (with 12 diseased vertebrae), and 2 case of spinal metastatic tumor (with 4 diseased vertebrae), the vital signs were record during operation. Pain relief and functional recovery were evaluated with visual analogue pain scale (VAS) and Oswestry disability index (ODI) scaling, and restoration of vertebral height and Cobb angle were evaluated by X-ray examination. Follow-up was conducted by telephone survey or clinic consults for 12.3 months (6 - 18 months). RESULTS: Operation was successfully performed on all patients with an operative time of 29.3 min (55 - 127 min) per vertebra. The average pressure of the balloon expansion was 165 Psi (87 - 210 Psi), and the average balloon expanded volume was 3.25 ml (1.5 - 4 ml). A balloon was expanded 2 approximately 5 times in one operation with the average of 2.94 expanded times. The bone cement volume injected was 3.95 ml (2 - 8.5 ml) per vertebra. Epidural cement leakage was seen in 1 vertebra in 1 case and paraspinal leakage was seen in two vertebrae in 1 case. The VAS and ODI scoring of these patients were both decreased significantly after operation. Both the anterior height and midline height of vertebrae were significantly improved. The pain relief and functional recovery were substantial and maintained to the last follow-up without any re-collapse or adjacent level fracture. CONCLUSION: one-stage single balloon multiple expansions PKP is effective, economic and safe in treatment of multi-level OVCF and spinal tumor.

Preliminary clinical outcomes of percutaneous kyphoplasty with Sky-bone expander.

BACKGROUND: Percutaneous kyphoplasty (PKP) using balloon expander has been proved to be effective in the treatment of painful vertebral compression fractures. Recently, Sky-bone expander, an alternative bone expander for PKP has been developed. The purpose of this study was to show our preliminary clinical outcomes of PKP with Sky-bone expander. METHODS: PKP with Sky-bone expander was performed in 25 patients (30 vertebrae). The operation time, bleeding volume, cement volume injected were recorded. The pain and functional activities of the patients before and after the operation were compared using Wilcoxon signed-rank test. The cement distribution in the vertebrae, vertebral height restoration, and kyphosis correction after the procedure were evaluated by radiography. The pre- and post-operative absolute values of the vertebral height and kyphotic angle were compared by paired-sample t test. All the patients were followed up by telephone or clinic consulting after being discharged from our hospital. RESULTS: The procedure was performed successfully in all the patients. Bipedicular injection was used in 2 of the patients, and unipedicular injection was made in the others. The operation time ranged from 25 to 120 minutes (45 minutes per vertebra on average). The average bleeding volume was about 20 ml. Polymethylmethacrylate 1.5-5.0 ml (mean, (3.15+/-0.78) ml) was injected through each pedicle into all the patients except one, who received calcium sulphate 3.5 ml instead. The patients were followed up for 12-15 months (13.5 months on average). The mean visual analogue scale (VAS) score, Oswestry Disability Index, anterior, midline, and posterior vertebral height, and kyphotic angle of the patients were improved significantly at the end of the follow-up compared with those before the operation. (2.5+/-1.3, 35.1%, (20.94+/-6.15) mm, (20.26+/-4.59) mm, (26.72+/-3.49) mm, and 8.2 degrees vs. 8.5+/-1.9, 61.2%, (19.11+/-6.72) mm, (15.88+/-5.73) mm, (25.78+/-3.67) mm, and 17.3 degrees; all P<0.05). The cement distribution with unipedicular injection was mostly limited within the injection site in the vertebral body. Cement extravasation was seen at ten levels (33.3%). CONCLUSIONS: PKP with Sky-bone expander is an effective and relatively safe alternative to the PKP using balloon expander. It can relieve pain, improve physical function, and restore the height of the collapsed vertebrae, but the cement extravasation is unsolved.

[Percutaneous vertebroplasty with EH composite material: an experiment study].

OBJECTIVE: To investigate the appropriate ratio of liquid/powder and use of radiopaque agent in EH composite material for percutaneous vertebroplasty (PVP). METHODS: (1) EH composite material was divided into 6 groups. The material without contrast with the liquid/powder ratios 8:9, 8:8, and 8:7 was classifieds as groups I, II, and III; and the EH composite material with the liquid/powder ratios 8:9, 8:8, and 8:7 and with the addition of 20% barium sulfate by weight was classified as the groups IV, V, and VI. The curing temperature was measured. The bone cement of different groups was made into cylinders to be X-rayed to observe the opacity. Universal tester was used to examine the strength and stiffness. (2) The vertebrae (T8 approximately L5) were isolated from the cadaver of an elder female patient with osteoporosis. Universal tester was used to examine the strength and stiffness of the vertebral bodies (VBs). Osteoporotic vertebral compression fracture (OVCF) model was made. PVP procedure was mimicked by puncturing through the bilateral pedicle of vertebral arch into the anterior 1/3 of the vertebral bodies and the EH composite materials of the groups II and V were injected into the VBs Then the temperatures of the geometric center (CT) and spinal canal posterior wall (PT) of the VBs were measured in a water bath with the temperature of 37 degrees C. Twenty-four hours later the vertebrae underwent X-ray examination to observe the opacity and underwent examination of strength and stiffness with universal tester. RESULTS: (1) The sticking periods (?) of the groups IV, V, and VI were significantly longer than those of the corresponding groups I, II, and III respectively by about 60 s, and the highest temperature of the groups IV, V, and VI were significantly lower than those of the corresponding groups I, II, and III respectively. Addition1 of barium sulfate increased the opacity of the bone cement, but did nor significantly influence the strength of the bone cement. The properties of the group V was the best. (2) The bone cement was easy to be injected into the VBs. The peak PT was not beyond 50 degrees C. After the injection of the bone cement of the groups II, the strength and stiffness of the VB were (1501.6 +/- 5.0) N/mm and (285.6 +/-) N/mm, both significantly higher than those before the injection [(547.5 +/- 3.1) N/mm and (104.1 +/- 1.3) N/mm]; and after the injection of the bone cement of the groups V, the strength and stiffness of the VB were (1355.0 +/- 4.5) N/mm and (257.7 +/- 1.9), both significantly higher than those before the injection [(543.8 +/- 2.7) N/mm and (103.4 +/- 1.1) N/mm]. The opacity of the VBs injected with the bone cement of the group V was better than those injected with the bone cement of the group II. CONCLUSION: The EH (8/8) with 20% barium sulfate is a proper and effective filling material for the treatment of OVCF.

[A comparison study of clinical application between balloon percutaneous kyphoplasty and "Sky-bone expander" percutaneous kyphoplasty].

OBJECTIVE: To compare the clinical results of balloon percutaneous kyphoplasty (PKP) and "Sky-bone expander" PKP. METHODS: From October 2004 to February 2006, 25 cases (57 vertebrae) balloon PKP and 24 cases (29 vertebrae) "Sky-bone expander" PKP procedures were performed. The operation time, bleeding volume, cement injected volume were recorded during operation. The patients' pain relief and functional activities recovery were evaluated after operation. The distribution of the cement and the restoration of vertebral height were also observed post-operation. All these patients were followed-up by telephone or clinic consults after discharged. RESULTS: All cases were successfully experienced procedures. There are no significant differences in operative time, bleeding volume and cost of every vertebrae in these two group (P > 0.05). The balloon group had larger cement injected volume per pedicle than Sky group (4.27 +/- 1.08) ml vs. (3.15 +/- 0.78) ml (P < 0.05). The VAS and ODI scoring of these two groups were both decreased significantly after operation. The vertebral height were restored in both two groups with anterior height and midline height restored significantly in balloon group and midline height restored significantly in Sky group. The cement distribution of "Sky-bone expander" PKP with unipediclar injection mostly limited in the injective side of the vertebral body, but most of the balloon PKP vertebrae with unipediclar injection can be seen a cross-midline cement distribution in the anterior-posterior position X ray film. CONCLUSIONS: Both balloon PKP and "Sky-bone expander" PKP are efficacious and safety in the treatment of vertebral compression fractures. "Sky-bone expander" PKP is more suitable for single level compressive fracture while balloon PKP is especially suitable for multiple level compressive fractures.