Calcium phosphate scaffolds combined with bone morphogenetic proteins or mesenchymal stem cells in bone tissue engineering

Objective:

The purpose of this study was to review the current status of calcium phosphate (CaP) scaffolds combined with bone morphogenetic proteins (BMPs) or mesenchymal stem cells (MSCs) in the field of bone tissue engineering (BTE).

Date Sources:

Data cited in this review were obtained primarily from PubMed and Medline in publications from 1979 to 2014, with highly regarded older publications also included. The terms BTE, CaP, BMPs, and MSC were used for the literature search.

Study Selection:

Reviews focused on relevant aspects and original articles reporting in vitro and/or in vivo results concerning the efficiency of CaP/BMPs or CaP/MSCs composites were retrieved, reviewed, analyzed, and summarized.

Results:

An ideal BTE product contains three elements: Scaffold, growth factors, and stem cells. CaP-based scaffolds are popular because of their outstanding biocompatibility, bioactivity, and osteoconductivity. However, they lack stiffness and osteoinductivity. To solve this problem, composite scaffolds of CaP with BMPs have been developed. New bone formation by CaP/BMP composites can reach levels similar to those of autografts. CaP scaffolds are compatible with MSCs and CaP/MSC composites exhibit excellent osteogenesis and stiffness. In addition, a CaP/MSC/BMP scaffold can repair bone defects more effectively than an autograft.

Conclusions:

Novel BTE products possess remarkable osteoconduction and osteoinduction capacities, and exhibit balanced degradation with osteogenesis. Further work should yield safe, viable, and efficient materials for the repair of bone lesions.

HbA1c and Lower Extremity Amputation Risk in Patients With Diabetes

In this meta-analysis, we aimed to assess glycosylated hemoglobin (HbA1c) level and lower extremity amputation (LEA) risk in patients with diabetes. Systematic computerized searches of the PubMed and Web of Knowledge were performed. We compared HbA1c level between groups with LEA and without LEA by meta-analysis; we also examined the dose–response relationship between HbA1c level and LEA risk. Sixteen studies were included in the meta-analysis. Eleven studies with 43 566 patients compared HbA1c between groups with and without LEA. The mean HbA1c (%) ranged from 8.3 to 12.5 in the group with LEA and from 7.4 to 11.3 in the group without LEA. The pooled weighted mean difference was 1.110 (95% confidence interval = 0.510-1.709; Z = 3.63, P = .008). The funnel plot was symmetrical, and Begg’s test ( z = 0.00, P = 1.000) and Egger’s test ( t = −0.02, P = .984) suggested no significant publication bias. Six studies with 109 933 patients included in the dose–response meta-analysis. The LEA incidence ranged from 0.3% to 14.6% between different HbA1c levels. Dose–response meta-analysis showed statistically significant association between HbA1c and LEA risk (χ2 = 65.51, P = .000). In linear model, the odds ratio for LEA incidence was 1.229 (95% confidence interval = 1.169-1.292) for every 1% HbA1c increase. In the spline model, the odds ratio of LEA risk increased with HbA1c levels, especially when HbA1c ranged from 5% to 9%. Our meta-analysis indicates that high level of HbA1c is an important risk factor for LEA in patients with diabetes. This evidence supports the strategy for lowering glucose levels to reduce amputation in patients with diabetes.

DAMGO depresses inhibitory synaptic transmission via different downstream pathways of μ opioid receptors in ventral tegmental area and periaqueductal gray

Opioid-induced rewarding and motorstimulant effects are mediated by an increased activity of the ventral tegmental area (VTA) dopamine (DA) neurons. The excitatory mechanism of opioids on VTA-DA neurons has been proposed to be due to the depression of GABAergic synaptic transmission in VTA-DA neurons. However, how opioids depress GABAergic synaptic transmission in VTA-DA neurons remain to be studied. In the present study, we explored the mechanism of the inhibitory effect of [D-Ala(2), N-Me-Phe(4), Gly(5)-ol]-enkephalin (DAMGO) on GABAergic synaptic transmission in VTA-DA neurons using multiple approaches and techniques. Our results showed that (1) DAMGO inhibits GABAergic inputs in VTA-DA neurons at presynaptic sites; (2) effect of DAMGO on GABAergic inputs in VTA-DA neurons is inhibited by potassium channel blocker 4-aminopyridine (4-AP) and Gi protein inhibitor N-ethylmaleimide (NEM); (3) phospholipase A2 (PLA2) does not mediate the effect of DAMGO on GABAergic inputs in VTA-DA neurons, but mediates it in the periaqueductal gray (PAG); (4) multiple downstream signaling molecules of μ receptors do not mediate the effect of DAMGO on GABAergic inputs in VTA-DA neurons. These results suggest that DAMGO depresses inhibitory synaptic transmission via μ receptor-Gi protein-Kv channel pathway in VTA-DA neurons, but via μ receptor-PLA2 pathway in PAG neurons.

Isolation of microsatellite loci for Rhodiola alsia (Crassulaceae), an important ethno-medicinal herb endemic to the Qinghai-Tibetan plateau

Rhodiola alsia, which has been used widely in traditional Chinese medicine for a considerable time, grows on moist habitats at high altitude near the snow line. Microsatellite loci were developed for R. alsia to investigate its population genetics. In total, 17 polymorphic microsatellites were developed based on ESTs from the Illumina HiSeq(TM) 2000 platform. The microsatellite loci were checked for variability using 80 individuals of R. alsia sampled from four locations on the Qinghai-Tibet Plateau. The total number of alleles per locus ranged from 10 to 20, and the observed heterozygosity ranged from 0.000 to 1.000. The null allele frequency ranged from 0.000 to 0.324. These microsatellites are expected to be helpful in future studies of population genetics in R. alsia and related species.

Pooled analysis of pomalidomide for treating patients with multiple myeloma

BACKGROUND

Patients with refractory or relapsed multiple myeloma are considered to have a very poor prognosis, and new regimens are needed to improve this setting. Pomalidomide is a new immunomodulatory drug with high in vitro potency. Immunomodulatory drugs are hypothesized to act through multiple mechanisms. Here we performed a systemic analysis to evaluate pomalidomide-based chemotherapy (pomalidomide in combination with low-dose dexamethasone) as salvage treatment for patients with refractory and relapsed multiple myeloma.

METHODS

Clinical studies evaluating the efffectiveness of pomalidomide based regimens on response and safety for patients with refractory and relapsed multiple myeloma were identified using a predefined search strategy. Pooled response rate (RR) of treatment were calculated.

RESULTS

For pomalidomide based regimens, 4 clinical studies which including 291 patients with refractory and relapsed multiple myeloma were considered eligible for inclusion. Systemic analysis suggested that, in all patients, pooled RR was 41.2% (120/291). Major adverse effects were hematologic toxicity, including grade 1 or 2 anemia, leucopenia and thrombocytopenia with pomalidomide based treatment. No treatment related death occurred.

CONCLUSION

This pooled analysis suggests that pomalidomide in combination with low-dose dexamethasone is active with good tolerability in treating patients with refractory or relapsed multiple myeloma.

Lumbar interbody fusion with porous biphasic calcium phosphate enhanced by recombinant bone morphogenetic protein-2/silk fibroin sustained-released microsphere: an experimental study on sheep model

Biphasic calcium phosphate (BCP) has been investigated extensively as a bone substitute nowadays. However, the bone formation capacity of BCP is limited owing to lack of osteoinduction. Silk fibroin (SF) has a structure similar to type I collagen, and could be developed to a microsphere for the sustained-release of rhBMP-2. In our previous report, bioactivity of BCP could be enhanced by rhBMP-2/SF microsphere (containing 0.5 µg rhBMP-2) in vitro. However, the bone regeneration performance of the composite in vivo was not investigated. Thus, the purpose of this study was to evaluate the efficacy of BCP/rhBMP-2/SF in a sheep lumbar fusion model. A BCP and rhBMP-2/SF microsphere was developed, and then was integrated into a BCP/rhBMP-2/SF composite. BCP, BCP/rhBMP-2 and BCP/rhBMP-2/SF were implanted randomly into the disc spaces of 30 sheep at the levels of L1/2, L3/4 and L5/6. After sacrificed, the fusion segments were evaluated by manual palpation, CT scan, biomechanical testing and histology at 3 and 6 months, respectively. The composite demonstrated a burst-release of rhBMP-2 (39.1 ± 2.8 %) on the initial 4 days and a sustained-release (accumulative 81.3 ± 4.9 %) for more than 28 days. The fusion rates, semi-quantitative CT scores, fusion stiffness in bending in all directions and histologic scores of BCP/rhBMP-2/SF were significantly greater than BCP and BCP/rhBMP-2 at each time point, respectively (P < 0.05). These findings indicate that the SF microspheres containing a very low dose of rhBMP-2 improve fusion in sheep using BCP constructs.

Outcomes of secondary laminoplasty for patients with unsatisfactory results after anterior multilevel cervical surgery

Objective

To investigate the causes for failed anterior cervical surgery and the outcomes of secondary laminoplasty.

Methods

Seventeen patients failed anterior multilevel cervical surgery and the following conservative treatments between Feb 2003 and May 2011 underwent secondary laminoplasty. Outcomes were evaluated by the Japanese Orthopaedic Association (JOA) Scale and visual analogue scale (VAS) before the secondary surgery, at 1 week, 2 months, 6 months, and the final visit. Cervical alignment, causes for revision and complications were also assessed.

Results

With a mean follow-up of 29.7±12.1 months, JOA score, recovery rate and excellent to good rate improved significantly at 2 months (p<0.05) and maintained thereafter (p>0.05). Mean VAS score decreased postoperatively (p<0.05). Lordotic angle maintained during the entire follow up (p>0.05). The causes for secondary surgery were inappropriate approach in 3 patients, insufficient decompression in 4 patients, adjacent degeneration in 2 patients, and disease progression in 8 patients. Complications included one case of C5 palsy, axial pain and cerebrospinal fluid leakage, respectively.

Conclusion

Laminoplasty has satisfactory results in failed multilevel anterior surgery, with a low incidence of complications.

Steroid-associated osteonecrosis: Epidemiology, pathophysiology, animal model, prevention, and potential treatments (an overview)

Steroid-associated osteonecrosis (SAON) is a common orthopaedic problem caused by administration of corticosteroids prescribed for many nonorthopaedic medical conditions. We summarised different pathophysiologies of SAON which have adverse effects on multiple systems such as bone marrow stem cells (BMSCs) pool, bone matrix, cell apoptosis, lipid metabolism, and angiogenesis. Different animal models were introduced to mimic the pathophysiology of SAON and for testing the efficacy of both prevention and treatment effects of various chemical drugs, biological, and physical therapies. According to the classification of SAON, several prevention and treatment methods are applied at the different stages of SAON. For the current period, Chinese herbs may also have the potential to prevent the occurrence of SAON. In the future, genetic analysis might also be helpful to effectively predict the development of ON and provide information for personalised prevention and treatment of patients with SAON.

Percutaneous kyphoplasty for the treatment of osteoporotic thoracolumbar fractures with neurological deficit: radicular pain can mimic disc herniation

Osteoporotic vertebral fractures (OVFs) are the common disease found in elderly population. Neurological deficit in OVFs is rare despite the involved posterior cortex of the fractured vertebral body, severe kyphotic deformity, or the instability at the fracture site. OVF with resulting neurological deficit was considered as a contraindication for vertebral augmentation techniques. We reported a rare case of a 75-year-old woman with L1, L2 osteoporotic vertebral fractures and L5/S1 disc herniation who presented with back pain and radicular pain extending along the posterior aspect of the left leg. Physical examination showed slight weakness of her flexor hallucis longus and absence of ankle jerk on her left leg. The result of a straight leg-raising test was limited to an angle of 50 degrees. The radiographs showed that the nerve root was compressed by the retropulsed bone fragment of the L2 vertebral body and a herniated disc at the level of L5/S1 on the left side. After L1 and L2 kyphoplasty the radicular pain as well as the back pain was completely disappeared. At her two-year follow-up examination, the patient was completely symptom free and reported no radicular pain. This case suggested that minimally invasive techniques such as kyphoplasty or vertebroplasty are effective in certain OVF patients with neurological deficit. Radicular pain could be caused by osteoporotic fracture that involves the posterior cortex of the vertebral body. Understanding the anatomy of nerve roots and pathogenetic mechanism of radicular pain is particularly important for treatment option.

Comparisons of three anterior cervical surgeries in treating cervical spondylotic myelopathy

Background

Anterior cervical discectomy and fusion (ACDF) was one of the preferred treatments for degenerative cervical spondylosis. However, the motion of adjacent segment was significantly increased after operation. So cervical disc arthroplasty have been suggested to keep the motion of adjacent segment. A new implant named dynamic cervical implant (DCI) has been developed to keep the motion of adjacent segment.

Methods

We retrospectively reviewed 91 patients treated for single level cervical spondylotic myelopathy with anterior cervical discectomy and fusion (ACDF), dynamic cervical implant (DCI) and cervical total disc replacement (CTDR) between sep 2009 and Mar 2011 in our hospital. They were divided into three groups by surgical methods: ACDF group (group A, 34 cases), DCI group (group B, 25 cases), CTDR group (group C, 32 cases). Operation time, intraoperative blood loss, preoperative and postoperative JOA score and JOA recovery rate were compared among the three groups. Pre-and postoperative hyperextension and hyperflexion radiograms were observed to measure range of motion (ROM) of C_2–7, operative and adjacent levels.

Results

There was no statistical difference in operative time, intraoperative blood loss, and JOA recovery rate (P > 0.05) among three groups. But the differences of their postoperative JOA scores and preoperative JOA scores were of statistical significance (P < 0.05). Compared the pre-and postoperative ROM of C_2–7, operative, upper and lower levels of each group respectively, the difference between preoperative ROM and postoperative ROM of group A were of statistically significant (P < 0.05), while was no statistically significant of group C (P > 0.05). There was no statistically significant difference between preoperative ROM and postoperative ROM of upper and lower levels in group B (P > 0.05), but had statistically significance of C_2–7 and operative levels (P < 0.05).

Conclusions

Three operations are effective therapies for single level cervical spondylotic myelopathy. But each group has respective advantages and disadvantages.

Bioactivity of porous biphasic calcium phosphate enhanced by recombinant human bone morphogenetic protein 2/silk fibroin microsphere

To prepare a bioactive bone substitute, which integrates biphasic calcium phosphate (BCP) and rhBMP-2/silk fibroin (SF) microsphere, and to evaluate its characteristics. Hydroxyapatite and β-tricalcium phosphate were integrated with a ratio of 60–40%. RhBMP-2/SF (0.5 μg/1 mg) microsphere was prepared, and its rhBMP-2-release kinetics was assed. After joining pore-forming agent (Sodium chloride, NaCl), porous BCP/rhBMP-2/SF were manufactured, and its characteristics and bioactivity in vitro were evaluated. Mean diameter of rhBMP-2/SF microsphere was 398.7 ± 99.86 nm, with a loading rate of 4.53 ± 0.08%. RhBMP-2 was released in a dual-phase pattern, of which fast-release (nearly half of protein released) focused on the initial 3 days, and slow-release sustained more than 28 days. With the increase in concentration of NaCl, greater was porosity and pore size, but smaller mechanical strength of BCP/rhBMP-2/SF. Material with 150% (w/v) NaCl had an optimal performance, with a porosity of 78.83%, pore size of 293.25 ± 42.77μm and mechanical strength of 31.03 MPa. Proliferation of human placenta-derived mesenchymal stem cells (hPMSCs) on leaching extract medium was similar to the normal medium (P = 0.89), which was better than that on control group (P = 0.03). Activity of alkaline phosphatase on BCP/rhBMP-2/SF surface was higher than on pure BCP at each time point except at 1 day (P < 0.05). RhBMP-2 has a burst release on early times and a sustaining release on later times. BCP/rhBMP-2/SF with 150% (w/v) pore-forming agent has excellent porosity, pore size and mechanical strength. The biomaterial induces proliferation and differentiation hPMSCs effectively.

Osteoblast-secreted factors promote proliferation and osteogenic differentiation of bone marrow stromal cells via VEGF/heme-oxygenase-1 pathway

The hypoxia-inducible factors (HIFα) are the critical factors that couple angiogenesis and osteogenesis by activating transcription of VEGF in osteoblasts. Mice lacking von Hippel-Lindau gene (Vhl), thus overexpressing HIFα in osteoblasts develop extremely dense and highly vascularized long bones. Here we provide evidence that osteoblasts lacking Vhl overexpress and secrete high levels of VEGF, which subsequently promotes the proliferation and osteogenic differentiation of bone marrow stromal cells (BMSC) by promoting expression of Heme oxygenase-1 (HO-1) in BMSC. Conditioned medium from osteoblasts Vhl (CM-CRE) promoted the proliferation and osteogenic differentiation of BMSC, in comparison with conditioned medium derived from normal osteoblasts (CM-GFP). Recombinant VEGF stimulated the proliferation and osteogenic differentiation of BMSC culturing in CM-GFP. By contrast, VEGF-neutralizing antibody inhibited the proliferation and osteogenic differentiation of BMSC culturing in CM-CRE. Treatment with a HO-1 inhibitor, SnPP, significantly inhibited VEGF-induced BMSC proliferation and osteogenic differentiation. On the contrary, activation of HO-1 with CoPP reversed the suppressing of VEGF-antibody on the proliferation and osteogesis of BMSC culturing in CM-CRE. These studies suggest that osteoblasts promote the proliferation and osteogenic differentiation of BMCS by VEGF/HO-1 pathway.

Long-term effects of evodiamine on expressions of lipogenesis and lipolysis genes in mouse adipose and liver tissues

Evodiamine, the major alkaloid component isolated from the fruit of dried, unripened Evodia rutaecarpa Bentham, affects the plasma levels of cholecystokinin and various biological events such as gastric emptying and gastrointestinal transit; these effects of evodiamine were previously investigated in male rats. In this study, we aimed to investigate the effects of evodiamine on average daily weight gain, rectal temperature, and expressions of genes involved in lipid metabolism in liver and adipose tissues. Evodiamine was added as a supplement, comprising 0.02, 0.04, and 0.06% of the diet fed to mice for 1, 2, 3, and 4 weeks. Results showed that average daily weight gain and rectal temperature decreased significantly over time in a dose-dependent manner. Evodiamine changed expressions of the peroxisome proliferator-activated receptor-g (PPARg) in mouse adipose and liver tissues in time- and dose-dependent manners. We found that evodiamine decreased mRNA expression of the sterol-regulatory element binding protein (SREBP-1c) and fatty acid synthase in adipose tissue. In addition, evodiamine increased expressions of hormone-sensitive lipase in both liver and adipose tissues. Interestingly, evodiamine increased the expression of triglyceride hydrolase only in adipose tissue. In conclusion, evodiamine could influence lipid metabolism through regulation of the expressions of its key genes, as well as reduce body heat and body weight.

Laminoplasty versus conservative treatment for acute cervical spinal cord injury caused by ossification of the posterior longitudinal ligament after minor trauma

BACKGROUND CONTEXT

No reports to date have accurately evaluated the management for acute spinal cord injury (SCI) caused by ossification of the posterior longitudinal ligament (OPLL) after minor trauma.

PURPOSE

To assess whether outcomes of laminoplasty is better than conservative treatment.

STUDY DESIGN/SETTING

A retrospective study.

PATIENT SAMPLE

Thirty-one patients underwent surgery (L group) and 29 patients underwent conservative treatment (C group).

OUTCOME MEASURES

Disability, muscle strength, sensation, and general health status.

METHODS

Patients were managed according to routine clinical practice and the results between groups were compared. Clinical and radiographic outcomes were assessed at admission, discharge, 6 months and at the final visit. Causes for trauma, duration of hospital stay, and complication were also evaluated.

RESULTS

Causes for trauma included falling, traffic accidents and sports. Mixed and segmental types were the most frequent cause of OPLL resulting into SCI. Duration of hospital stay and complications were less in the L group. Motor and sensory scores increased in the L group at discharge (p<.05) and at 6 months (p<.05), and maintained thereafter (p>.05); scores improved significantly in the C group at 6 months (p<.05), with a slight deterioration with time (p>.05); scores in the L group were higher than in the C group at each time point after surgery (p<.05). Bodily pain and mental health in SF-36 improved at discharge in the L group (p<.05); all scores improved at 6 months in both the groups (p<.05), with better improvements in the L group (p<.05). The canal diameter increased and occupation ratio decreased in the L group (p<.05), and maintained thereafter (p<.05); a slight increase of occupation ratio was observed in the C group (p>.05). Lordotic angle and range of motion were maintained in both the groups, with no significance between groups (p>.05). High-signal intensity decreased at 6 months (p<.05) in the L group; no significant change was found in the C group during the follow-up (p>.05); Significant difference was detected between the groups at 6 months and at the final visit (p<.05).

CONCLUSIONS

Most of the OPLL patients displayed as incomplete SCI after minor trauma. Although spontaneous improvement of SCI without surgery is often observed, laminoplasty has more satisfactory outcomes, prevents late compression of cord, and reduces perioperative complications, although with no significant benefit in cervical alignment and range of motion.

Collagen scaffolds modified with collagen-binding bFGF promotes the neural regeneration in a rat hemisected spinal cord injury model

Nerve conduit is one of strategies for spine cord injury (SCI) treatment. Recently, studies showed that biomaterials could guide the neurite growth and promote axon regeneration at the injury site. However, the scaffold by itself was difficult to meet the need of SCI functional recovery. The basic fibroblast growth factor (bFGF) administration significantly promotes functional recovery after organ injuries. Here, using a rat model of T9 hemisected SCI, we aimed at assessing the repair capacity of implantation of collagen scaffold (CS) modified by collagen binding bFGF (CBD-bFGF). The results showed that CS combined with CBD-bFGF treatment improved survival rates after the lateral hemisection SCI. The CS/CBD-bFGF group showed more significant improvements in motor than the simply CS-implanted and untreated control group, when evaluated by the 21-point Basso-Beattie-Bresnahan (BBB) score and footprint analysis. Both hematoxylin and eosin (H&E) and immunohistochemical staining of neurofilament (NF) and glial fibrillary acidic protein (GFAP) demonstrated that fibers were guided to grow through the implants. These findings indicated that administration of CS modified with CBD-bFGF could promote spinal cord regeneration and functional recovery.

Transpedicular intracorporeal grafting for patients with thoracolumbar burst fractures

OBJECTIVE

To evaluate the efficacy of reinforcing short-segment fixation with transpedicular intracorporeal grafting in restoring vertebral body height and preventing loss of correction in patients with thoracolumbar burst fractures.

METHODS

This retrospective study was carried out from the Affiliated Hospital of Jiangsu University, Jiangsu, China. Forty-six patients with thoracolumbar burst fractures without neurological deficit were operatively treated between July 2008 and June 2011. Patients in group A (n=21) were treated by short-segment fixation with transpedicular intracorporeal grafting, whereas patients in group B (n=25) were treated by short-segment fixation without bone grafting. The preoperative, postoperative, and follow-up radiographs (anterior, middle, posterior vertebral height, and local kyphosis angle) were evaluated.

RESULTS

All 46 patients in both groups obtained satisfactory reduction of fractured vertebrae. There were no significant differences between the 2 groups according to the improvement of body height and local kyphosis angle. However, correction losses were observed in both groups. Less losses of anterior body height (p=0.0007), middle body height (p<0.0001), and local kyphosis angle (p=0.0447) were detected in group A than group B. The rate of failure in group A (4.8%) was significantly lower than that in group B (28.0%) (p=0.0383).

CONCLUSION

Reinforcement of short-segment fixation with transpedicular intracorporeal grafting can effectively restore vertebral body height and prevent loss of correction for patients with thoracolumbar burst fractures.

All levels versus alternate levels plate fixation in expansive open door cervical laminoplasty

BACKGROUND

Expansive open door laminoplasty with the use of titanium miniplate is becoming popular. Usually, the plate is applied at each level to prevent re-closure of the opened lamina. However, it is also used at alternating levels (i.e., C3, C5 and C7) in clinical settings in order to reduce the cost. Whether they have any difference in clinical efficacy? There is a lack of comparative data between the two kinds of plate fixation in the literature.

MATERIALS AND METHODS

83 patients who underwent cervical laminoplasty with alternating levels plate fixation (51 patients in Group A) or all levels plate fixation (32 patients in Group B) between January 2008 and October 2012 were evaluated in our institute retrospectively. Clinical and radiologic outcomes were assessed.

RESULTS

No statistical difference was found in the mean operation time, blood loss, incidence of significant axial symptoms and C5 palsy, preoperative anteroposterior diameter (APD) and preoperative Japanese Orthopedic Association score between the two groups. However, Group B showed a higher rate of neurologic recovery after surgery. Postoperative increased APD and open angle in Group B were significantly larger than Group A. The mean cost for Group B (12801 ± 460.6 USD) was higher than Group A (8906 ± 566.7 USD).

CONCLUSIONS

Despite the higher cost of all level fixation, it is more effective in maintaining the expansion of the spinal canal and can obtain better clinical improvement compared to alternating levels fixation.

Unilateral versus bilateral balloon kyphoplasty for osteoporotic vertebral compression fractures

BACKGROUND

Osteoporotic vertebral compression fractures (VCFs) commonly occur in aged people. Balloon kyphoplasty (KP) has been proven to be efficacious for pain relief and reduction of vertebral height for patients with osteoporotic VCFs. However, very little is known about the comparison of clinical and radiographic outcomes between unilateral and bilateral balloon KP in treating this kind of patients.

OBJECTIVE

To compare the safety and long-term radiographic and clinical outcomes of unilateral or bilateral balloon KP to treat patients with osteoporotic VCFs.

STUDY DESIGN

A systemic review and meta-analysis of all randomized controlled trials (RCTs) comparing the analgesic efficacy, radiographic outcomes, and complications between unilateral and bilateral balloon KP in patients with osteoporotic VCFs.

SETTING

The MEDLINE, EMBASE, Pubmed, CINAHL databases, Bandolier, and the Cochrane Controlled Trials Register were systematically searched for evidence from their inception to July 2012 by 2 of the authors (J.L. and L.Z.).

METHODS

Relevant reports were reviewed by 2 assessors independently and the reference lists of retrieved papers were scrutinized to identify further studies for inclusion, using guidelines set by PRISMA statement criteria.

RESULTS

Three RCTs were enrolled in this study. The VAS scores showed no statistical difference between the groups before surgery and either at short-term or long-term follow-up. There was no statistical significance in polymethylmethacrylate (PMMA) leakage between the groups. Analysis of 2 studies showed statistical significance in surgery time (WMD -23.77 [-27.83, -19.71]; P < 0.00001) and PMMA (WMD -1.65 [-2.28, -1.02]; P < 0.00001) consumption between the groups.

LIMITATIONS

There were few data sources from which to extract abstracted data or published studies. There were only 3 RCTs that met criteria enrollment in this meta-analysis. The quality of these trials was quite low (Jadad score: 1-2). Variable reporting of end points and inconsistent definitions meant that we were not able to include every study for each outcome. There was also clinical heterogeneity among the studies.

CONCLUSION

The efficacy of both unilateral and bilateral balloon KP to provide rapid, significant, and sustained pain relief for patients with osteoporotic VCFs is validated. Unilateral balloon KP is a reasonable treatment for patients with osteoporotic VCFs considering that it could achieve equivalent pain relief with less surgery time and PMMA consumption compared to bilateral balloon KP. There was no evidence to prove that unilateral balloon KP results in higher incidence of PMMA leakage than bilateral balloon KP. Although unilateral balloon KP was less efficacious in the reduction of fractured vertebral body, it is still unclear if the clinical results of balloon KP were positively correlated with the restoration of vertebral height and amount.

Biomechanical characteristics of cement/gelatin mixture for prevention of cement leakage in vertebral augmentation

PURPOSE

This study evaluated whether or not the addition of gelatin micro-particles into the polymethyl methacrylate (PMMA) could reduce cement infiltration in cancellous bone of vertebra.

METHODS

Gelatin micro-particles were prepared in various sizes and mixed with PMMA in different densities. Dynamic viscosity of the mixture was measured by a rotational rheometer. Fresh bovine vertebral bodies were sectioned into cylindrical samples. Permeability of the mixture through the samples was tested on a mechanical test machine, and calculated using Darcy's law. The PMMA/gelatin mixture also underwent compressive and bending tests, and their structures were examined by scanning electron microscopy.

RESULTS

The cement/gelatin mixture increased the viscosity. Significant reduction of cement permeability in cancellous bone was determined after the addition of the micro-particles. Micro-particles of 2 % in density and 125-250 μm in size decreased the permeability by 1/3 without any significant change of the cement viscosity. The biomechanical strength was unchanged in compression but decreased by up to 20 % in bending.

CONCLUSIONS

Gelatin micro-particles significantly increased the cement viscosity, reduced the permeability in cancellous bone of vertebra, decreased the flexural strength, but did not affect the compressive strength. Although it suggested a manageable approach in vertebral augmentation, the outcome should be further verified on a cadaveric model or an animal model before the mixture could be used safely and effectively in the clinical treatment.

Simultaneous bilateral quadriceps tendon rupture in a patient with hyperparathyroidism undergoing long-term haemodialysis: a case report and literature review

Simultaneous bilateral quadriceps tendon rupture is a rare injury that represents < 5% of all quadriceps tendon ruptures. It is generally associated with chronic metabolic disorders and is seen in patients with uraemia undergoing maintenance haemodialysis. The present case was a 46-year-old man who presented with pain and the inability to extend his knees following a minor accident. A physical examination combined with X-radiography and magnetic resonance imaging investigations resulted in a diagnosis of bilateral quadriceps tendon rupture. He had a history of uraemia and had received regular haemodialysis for 7 years. He had high levels of serum parathyroid hormone and he was diagnosed with secondary hyperparathyroidism. Following surgical repair of both quadriceps tendons, in addition to management of the secondary hyperparathyroidism, the patient regained full active mobility of both knee joints and was able to participate in normal activities of daily living.

Differential expression of lipid metabolism genes in the liver and adipose tissue of mice treated with evodiamine

Evodiamine is the main active alkali of Wu Zhuyu, a widely distributed Chinese herb. It plays an important role in the regulation of body fat deposition. In this study, we aimed to investigate the effect of evodiamine administration on the expression of genes involved in lipid metabolism in the liver and adipose tissue. Fasted mice were subcutaneously injected with evodiamine (37 °C, 20 mg/kg), and the core body temperature change and expression levels of lipid metabolism-related genes were evaluated at baseline, 0.5, 1, and 2 h. We detected the mRNA expression of fatty acid synthesis enzyme (FAS), peroxisome proliferator-activated receptor gamma (PPAR-γ), sterol regulatory element binding protein 1c (SREBP-1c), triglyceride hydrolase (TGH), and hormone-sensitive lipase (HSL) by real-time PCR and analyzed their correlation with core body temperature. Our results showed that the core body temperature was reduced greater than 1 °C with evodiamine treatment at 1 and 2 h (P < 0.01). In mouse livers, SREBP-1c, HSL, and TGH mRNA expression was significantly increased, and they reached the highest levels 1 h after injection (P < 0.01). However, PPAR-γ mRNA expression was decreased and reached a significant level at 0.5 h (P < 0.01) and FAS mRNA expression was not significantly different; FAS and SREBP-1c mRNA expression were reduced and reached significant levels at 1 h (P < 0.01). Of note, other genes demonstrated opposite changes in adipose tissue, and HSL mRNA expression was significantly reduced at 0.5 h (P < 0.01). The decreasing core temperature had a significant negative correlation with the expression of TGH, HSL, FAS, and SREBP- 1c mRNA in the liver (P < 0.01), but had significant positive correlation with levels of FAS and SREBP-1c mRNA in adipose tissue (P < 0.01). In light of these results, the main mechanism of the regulation of body fat deposition by evodiamine is raising energy consumption through reducing body temperature and promoting fat decomposition.

Construction of suppressor of cytokine signaling 2 (SOCS2) adenoviral overexpression vector and its impact on growth-hormone-induced lipolysis in swine primary adipocytes

We investigated the effect of overexpression suppressor of cytokine signaling 2 (SOCS2) on lipolysis in swine primary adipocytes (pAd) induced by growth hormone (GH). We constructed pAd-SOCS2 adenoviral overexpression vectors to infect HEK293 cells for virus packaging and propagation. Cultured swine primary adipocytes were infected with virus particles; after 48 h the infected adipocytes were treated with 500 ng GH/mL in the growth medium. Lipometabolism-related gene expressions were detected at 0, 0.25, 0.5, 1, 2, and 4 h, by measuring mRNA and protein levels. The pAd-SOCS2 overexpression vector was successfully constructed and the concentration of titrated virus was 1.2 x 10(9) PFU/mL. We found that virus infection significantly increased SOCS2 mRNA and protein levels in swine primary adipocytes. Overexpression of SOCS2 significantly inhibited the increase in fatty acid synthase, adipose triglyceride lipase mRNA, and protein expression at 0.5 h. However, after 0.5 h, this inhibition was not significant. We concluded that overexpression of SOCS2 inhibited the increase in lipolysis induced by GH in swine primary adipocytes; this could provide a basis for studies of lipometabolism.

Comparison of lumbar interbody fusion performed with unilateral or bilateral pedicle screw

Currently, bilateral pedicle screw fixation is the standard of instrumentation, providing rigid fixation and an increased fusion rate. However, due to the excessive rigidity of the system, this instrumentation has been suspected to cause degeneration of adjacent segments. Alternatively, less rigid unilateral pedicle fixation is considered to be as effective as bilateral constructs. Few studies have compared unilateral and bilateral constructs in the treatment of lumbar degenerative disease. The purpose of this retrospective study was to evaluate possible differences between unilateral and bilateral pedicle screw fixation for single-level lumbar degenerative disease.Between October 2006 and October 2010, sixty consecutive patients were treated with unilateral pedicle screw fixation (28 patients) or bilateral pedicle screw fixation (32 patients) at the authors' institution. Oswestry Disability Index and visual analog scale scores showed a statistical difference between preoperative values and 3- and 6-month postoperative values (P<.05). Unilateral fixation resulted in shorter operative times and less intraoperative blood loss. No significant difference was found between the 2 fixation methods in terms of fusion rate and complication rate (P>.05).Lumbar interbody fusion with unilateral pedicle screw fixation was an effective and convenient method of treatment of single-level lumbar degenerative disease, with little surgical trauma.