[Show abstract][Hide abstract] ABSTRACT: Human ligamentum flavum(LF)-derived stem cells (LFSCs) and nucleus pulposus cells (NPCs) were cocultured under normoxia or hypoxia.
To isolate and identify human LFSCs and determine whether they can differentiate into NPCs when cocultured with NPCs under hypoxia.
Mesenchymal stem cell (MSC)-based therapies have been proposed as a biological treatment for intervertebral disc degeneration. MSCs derived from various tissues are leading candidates for cell-based therapies, but such cells have not been reported in LF.
LF cells were isolated from patient samples and cultured using culture flasks coated with fibronectin, and their identity was confirmed using flow cytometry. The cells were induced to differentiate into osteoblasts, chondrocytes, and adipocytes, and their morphology, immunophenotype, cell proliferation capacity, cell cycle and expression of stem cell-specific genes were compared with those of bone marrow-MSCs (BM-MSCs) derived from the same patients. NPCs and LFSCs were cocultured in 1-μm-pore-size insert transwell-culture systems under hypoxia (2% O2) or normoxia. CD24 expression was measured by flow cytometry and confocal microscopy assay. On Day 14, RT-PCR was used for comparing the expression of chondrogenic genes (Sox-9, collagen-II, aggrecan) and novel marker genes (KRT19, CA12, FOXF1, HIF-1α) between the 2 groups, and western blotting was performed for comparing HIF-1α, Sox-9, aggrecan, and collagen-II expression.
LFSCs were obtained using the fibronectin differential-adhesion assay. The morphology of LFSCs was altered, and their immunophenotype, multilineage induction, cell proliferation capacity, cell cycle and stem cell-specific gene expression were similar to BM-MSCs. CD24 expression was highly significant in the differentiated LFSCs. Real-time PCR and western-blotting results revealed that compared with LFSCs grown under normoxia, hypoxia-treated LFSCs expressed higher levels of Sox-9, collagen-II, aggrecan, KRT19, CA12, FOXF1, and HIF-1α genes and HIF-1α, collagen-II, Sox-9, and aggrecan proteins.
Stem cells were identified in human LF, and LFSCs cocultured with NPCs were successfully differentiated into NP-like cells under hypoxia. This potentially provides new cell candidates for cell-based regenerative medicine and tissue engineering.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
The goal of this article is to evaluate the efficacy and the safety of the percutaneous vertebroplasty (PVP) versus percutaneous kyphoplasty (PKP) in dealing with the osteoporotic vertebral compression fracture (OVCF).
In July 2014, a comprehensive systematic computer-based online search was performed by using the databases of PubMed, EMBASE, Cochrane Library, Web of Science, Wan Fang, and the China Biological Medicine. Only prospective comparative trials (PCT) and randomized controlled trials (RCT) that compared PVP with PKP were included. Trials were screened based on the inclusion and exclusion criteria previously formed. The Cochrane collaboration guidelines were also used to assess the quality of these included studies. The primary data of these studies [volume of the cement, postoperative vertebral height, visual analog scale (VAS) score and Oswestry Disability Index (ODI) score after the surgery, and so on] were carefully abstracted and processed by Revman 5.2.0 software The publication bias of the main results (cement leakage and adjacent-level fracture) were examined by Stata 12.0 (Begg and Egger test). Furthermore, the stability of the main results were also detected by sensitivity and cumulative analyses.
Six RCT and 14 PCT studies involving 1,429 patients met our criteria and were included finally. Comparing these two methods, the PKP group took more operation time [SMD = 0.66, 95 % CI (0.28, 1.03), p = 0.0006] with higher anterior vertebral body height [SMD = 1.40, 95 % CI (0.49, 2.32), p = 0.003], greatly reduced Cobb angle in the long run [SMD = -0.61, 95 % CI (-1.04, -0.19), p = 0.005] and had lower risk of cement leakage. However, in VAS scores and ODI scores after the surgery whether for the short-term efficacy (no more than 1 week after the surgery) or long-term efficacy (more than six months), Cobb angle in the short run and new fracture in the adjacent level, no statistically differences were found between the two groups.
Based on current evidence, PVP takes less time in the operation, while it has greater risk of cement leakage, was inferior in reducing Cobb angle in the long term and results in lower anterior vertebral body height after the surgery. For pain relief, which is the main desire of the patients, both procedures provide significant improvement in VAS and ODI pain scores. PVP is still an effective procedure.
International Orthopaedics 09/2014; 39(3). DOI:10.1007/s00264-014-2525-5 · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to compare the safety and efficacy of minimally invasive discectomy (MID) with standard discectomy (SD) and determine whether the use of the MID technique could decrease the recurrence of lumbar disc herniation (LDH) after the surgery.
In February 2014, a comprehensive search was performed in PubMed, EMBASE, Web of Science, Cochrane Library and the Chinese Biological Medicine Database. Only randomised controlled trials (RCT) that compared MID with SD for the surgical management of LDH were included. These trials were carefully picked out following the inclusion and exclusion criteria. Using the Cochrane Collaboration guidelines, two authors independently extracted data and assessed these trials' quality. The age of the patients, size of incision, surgical time, blood loss, visual analogue scale (VAS) score after the surgery, hospital stay, disc herniation recurrence, X-ray exposure and surgical costs in these studies were abstracted and synthesised by a meta-analysis with RevMan 5.2.0 software, and the main results (VAS score after the surgery and disc herniation recurrence) of publication bias were examined by Stata 12.0.
Overall, 16 trials involving 2,139 patients meeting our criteria were included and analysed. Comparing MID and SD, the former was more likely to increase disc herniation recurrence [relative risk (RR) = 1.95, 95 % confidence interval (CI) 1.19-3.19, p = 0.008], and it involved a smaller size of incision [mean difference (MD) = -1.91, 95 % CI -3.33 to -0.50, p = 0.008], shorter hospital stay, longer operating time (MD = 11.03, 95 %C I 6.62-15.44, p < 0.00001) and less blood loss (MD = -13.56, 95 % CI -22.26 to -4.87, p = 0.002), while no statistical difference appeared with regard to the age of the patients, VAS score after the surgery, X-ray exposure, hospital stay and surgical costs.
Based on available evidence, MID results in less suffering for patients during the hospital course with a similar clinical efficacy compared to SD. This makes MID a promising procedure for patients with LDH; however, to popularise it greater effort is required to reduce disc herniation recurrence.
International Orthopaedics 04/2014; 38(6). DOI:10.1007/s00264-014-2331-0 · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In a general view of anatomy, intervertebral disc (IVD) is composed of three parts: annulus fibrosus (AF), nucleus pulposus (NP) and cartilage endplate (CEP). Recently, several types of stem cells were successfully isolated from these corresponding regions, but up to now, no research was performed about which kind of stem cells is the most efficient candidate for NP tissue engineering or for stem cell based disc regeneration therapy? In this study, we compared the regenerative potentials of the above-mentioned three kinds of disc derived stem cells with that of the classic BM-MSCs in a rabbit disc degeneration model. By MRI, X-ray and histology etc evaluations, we found that cartilage endplate derived stem cells (CESCs) showed superior capacity than that of the annulus fibrosus derived stem cells (AFSCs), nucleus pulposus derived stem cells (NPSCs) and BM-MSCs (P<0.05), additionally when comparing the CESCs group with the normal control group, there existed no statistical difference in X-ray (P>0.05). Those results demonstrated that CESCs-seeded alginate construct performed the most powerful ability for NP regeneration, while AFSCs showed the most inferior potency, NPSCs and BM-MSCs had similar regenerative capacity and located in the middle. All in all, our study showed that CESCs might act as an efficient seed cell source for NP tissue engineering, which paved a new way for the biological solution of disc degeneration diseases (DDD).
Tissue Engineering Part A 10/2013; 04(S 01). DOI:10.1089/ten.TEA.2012.0703 · 4.64 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the characteristics of patients with traumatic vertebral fractures and concomitant fractures of the first rib and their management.
From January 2001 to December 2010, 17/3142 patients (0.5%) with traumatic vertebral fractures who presented to our hospitals had concomitant fractures of the first rib.
The study included 14 men (82.4%) and 3 women (17.6%) patients of age 32-57 years (mean, 46.6 years). The mechanisms of trauma were falls from heights in seven, motor vehicle accidents in five and direct collisions with blunt objects in five. Thirteen patients (76.5%) presented initially with pulmonary complications after sustaining trauma. Three patients sustained one rib fracture, two three rib fractures, three four rib fractures and 10 > five rib fractures. The injuries were right-sided in three cases, left-sided in three and bilateral in eleven. Four patients (23.5%) presented with craniocerebral injuries. According to the American Spinal Injury Association (ASIA) classification, 10 patients (58.8% of the total study group) had motor and sensory deficits (ASIA A-D). There were no vascular injuries or deaths.
Traumatic vertebral fractures with concomitant fractures of the first rib are associated with multisystem injuries, but not always with morbidity and mortality. A multidisciplinary approach, early diagnosis, appropriate treatment and observation in the intensive care unit may prevent morbidity and/or mortality.
Orthopaedic Surgery 05/2013; 5(2):100-4. DOI:10.1111/os.12039
[Show abstract][Hide abstract] ABSTRACT: Parathyroid hormone-related peptide (PTHrP) is an important inductive factor during chondrogenesis of mesenchymal stem cells (MSCs). PTHrP induces chondrogenesis and suppresses hypertrophy, yet the lack of an efficient delivery system limits its use for cartilage tissue engineering in clinical application. In this study, a peptide of 7 amino acids was first used to engineer PTHrP to construct a collagen-targeting system. This peptide functioned as a collagen-binding domain (CBD) to specially target the PTHrP to collagen. ELISA assay was used to determine the collagen-binding ability of CBD-PTHrP. The effect of CBD-PTHrP on chondrogenesis was measured by an in vitro pellet assay in bone marrow-derived MSCs (BM-MSCs). As expected, the CBD peptide promoted the binding of CBD-PTHrP to collagen when compared to NAT-PTHrP. Furthermore, the recombinant protein CBD-PTHrP induced the expression of COL2A1 and Sox-9, inhibited the expression of COL1A1 at the mRNA and protein levels as effectively as NAT-PTHrP. Safranin-O and immunohistochemistry for collagen types Ⅰ, Ⅱ, Ⅹ and Sox-9 generally paralleled qRT-PCR and western blotting findings with minor variations. In conclusion, our study demonstrated that CBD-PTHrP is a collagen-targeting system and promotes in vitro chondrogenesis in BM-MSCs. We suggest that this is an efficient delivery system for cartilage tissue engineering in clinical application.
International Journal of Molecular Medicine 12/2012; 31(2). DOI:10.3892/ijmm.2012.1219 · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Macrophage migration inhibitory factor (MIF) is a multifunctional cytokine that regulates inflammatory reactions and the pathophysiology of many inflammatory diseases. Intervertebral disc (IVD) degeneration is characterized by an inflammatory reaction, but the potential role of MIF in IVD degeneration has not been determined. Recent studies have shown that MIF and its receptor, CD74, are involved in regulating the migration of human mesenchymal stem cells (MSCs); Thus, MIF might impair the ability of mesenchymal stem cells (MSCs) to home to injured tissues. Our previous studies indicated that cartilage endplate (CEP)-derived stem cells (CESCs) as a type of MSCs exist in human degenerate IVDs. Here, we investigate the role of MIF in regulating the migration of CESCs.
CESCs were isolated and identified. We have shown that MIF was distributed in human degenerate IVD tissues and was subject to regulation by the pro-inflammatory cytokine TNF-α. Furthermore, in vitro cell migration assays revealed that nucleus pulposus (NP) cells inhibited the migration of CESCs in a number-dependent manner, and ELISA assays revealed that the amount of MIF in conditioned medium (CM) was significantly increased as a function of increasing cell number. Additionally, recombinant human MIF (r-MIF) inhibited the migration of CESCs in a dose-dependent manner. CESCs migration was restored when an antagonist of MIF, (S, R)-3(4-hydroxyphenyl)-4, 5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1), was added. Finally, a CD74 activating antibody (CD74Ab) was used to examine the effect of CD74 on CESCs motility and inhibited the migration of CESCs in a dose-dependent manner.
We have identified and characterized a novel regulatory mechanism governing cell migration during IVD degeneration. The results will benefit understanding of another possible mechanism for IVD degeneration, and might provide a new method to repair degenerate IVD by enhancing CESCs migration to degenerated NP tissues to exert their regenerative effects.
PLoS ONE 11/2012; 7(8):e43984. DOI:10.1371/journal.pone.0043984 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Far lateral lumbar disc herniation (FLLDH) accounts for 2.6% to 11.7% of all lumbar herniated discs. Numerous surgical approaches have been described for treating this condition. The purpose of this study was to evaluate minimally invasive surgical techniques for the treatment of FLLDH.
From June 2000 to March 2006, 52 patients with FLLDH were treated with minimally invasive procedures. All patients were assessed by anteroposterior and lateral roentgenography and computed tomography (CT). Some patients underwent myelography, discography, and magnetic resonance imaging. Procedures performed included Yeung Endoscopy Spine System (YESS) (n = 25), METRx MicroDiscectomy System (n = 13), and X-tube (n = 14). Patients were followed up for a mean of 13.5 months. Clinical outcomes were assessed using a visual analog scale (VAS) and Nakai criteria.
All 3 procedures significantly improved radiating leg symptoms (P < 0.005). After surgery, 84.0%, 84.6%, and 92.8% of patients in the YESS, METRx, and X-tube groups had excellent or good outcomes. There were no statistically significant differences of VAS scores between the groups. The YESS procedure was associated with the shortest operation time, simplest anesthesia, and least trauma compared with the other 2 procedures, especially for type I herniations. The METRx procedure was the most suitable for type II herniations and posterior endoscopic facetectomy. Posterior lumbar interbody fusion and unilateral pedicle screw instrumentation with X-tube was the most suitable for herniations combined with degenerative lumbar instability (type III).
Minimally invasive strategies and options should be determined with reference to the type of FLLDH.
Chinese medical journal 03/2012; 125(6):1082-8. DOI:10.3760/cma.j.issn.0366-6999.2012.06.022 · 1.05 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Only 12 cases of musculoskeletal tuberculosis (TB) that occurred at the site of recent blunt trauma have been previously described.
A 43-year-old previously healthy man experienced an uncomplicated bursting fracture at the L2 vertebra without any spinal tuberculosis (ST)-associated evidence. During the conservative treatment, he was in good physical condition with back pain totally subsiding and occasional ambulation in a spinal brace, whereas 7 months after the original trauma, he presented with a characteristic manifestation of ST at the same vertebra.
Intraoperatively, biopsy confirmed ST of the L2 vertebra and radical debridement with an anterior fusion was performed. The patient received an 18-month course of anti-TB regimen. Excellent clinical outcomes were achieved.
In developing countries, where TB is still widely prevalent, there must be a heightened awareness of the risk of ST at recently fractured vertebrae, as demonstrated in this case.
[Show abstract][Hide abstract] ABSTRACT: To retrospectively analyze the treatment of lumbar spondylolisthesis using minimally invasive and open transforaminal lumbar interbody fusion (TLIF), and compare the clinical results of two techniques.
From June 2006 to May 2010, 371 patients with lumbar spondylolisthesis grade 1 and 2 were treated with TLIF, pedicle screw fixation and followed up. The mean age was 50.4 years (range, 37 - 85 years). There were 172 patients who underwent minimally invasive TLIF and percutaneous pedicle screw fixation were set as the MIS-TLIF group, 199 patients who underwent open TLIF and pedicle screw fixation were set as the OTLIF group. The operative time, blood loss, X-ray exposure time and complications were compared between the two groups. Clinical outcome was assessed using the visual analog scale (VAS) and the Oswestry disability index (ODI). Fusion rates were determined by using CT scan reconstruction and dynamic lumbar radiography in last fellow-up.
The average follow-up duration was 32.7 months with a range of 12-58 months. The gender, age, classification of spondylolistheis and level of fusion showed a identical pattern in both groups. The mean intra-operative blood loss (310 ± 75) ml and postoperative blood loss (38 ± 13) ml in MIS-TLIF group were significantly superior to the intra-operative blood loss (623 ± 156) ml and postoperative blood loss (184 ± 72) ml in OTLIF group (t = 2.836 and 3.274, P < 0.01). Comparing with the OTLIF group (20 ± 10) s, the MIS-TLIF group had a significantly longer radiation time (51 ± 19) s (t = 2.738, P < 0.01). There was no statistical difference in operating time, lower back pain VAS scores, ODI scores and incidence of complication between the two groups.
Comparing with open TLIF, minimally invasive TLIF is a safe and reliable procedure for treatment of lumbar spondylolisthesis grade 1 and 2 with potential advantages.
Zhonghua wai ke za zhi [Chinese journal of surgery] 12/2011; 49(12):1076-80.
[Show abstract][Hide abstract] ABSTRACT: Cartilage endplate (CEP) degeneration is usually accompanied by loss of cellularity, and this loss may be a crucial key factor in initiation and development of degenerative disc disease. The study of cell types in degenerated CEP could help in understanding CEP etiopathogenesis, and may help in devising new treatments, especially if the presence of progenitor cells could be demonstrated. The aim of this study was to determine if progenitor cells existed in degenerated human CEP.
Cells isolated from CEP were cultured in a three-dimensional agarose suspension to screen for proliferative cell clusters. Cell clusters were then expanded in vitro and the populations were analyzed for colony forming unit, immunophenotype, multilineage induction, and expression of stem cell-related genes.
The presence of progenitor cells in degenerated human CEP is indicated by the results of CFU, immunophenotype, multilineage induction, and expression of stem cell-related genes.
We believe that this is the first study which has conclusively shown the presence of progenitor cells in degenerated CEP. The finding of this study may influence the clinical management of degenerative disc disorder.
European Spine Journal 10/2011; 21(4):613-22. DOI:10.1007/s00586-011-2039-4 · 2.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Mesenchymal stem cells (MSCs) derived from adult tissues are an important candidate for cell-based therapies and regenerative medicine due to their multipotential differentiation capability. MSCs have been identified in many adult tissues but have not reported in the human intervertebral disc cartilage endplate (CEP). The initial purpose of this study was to determine whether MSCs exist in the degenerated human CEP. Next, the morphology, proliferation capacity, cell cycle, cell surface epitope profile and differentiation capacity of these CEP-derived stem cells (CESCs) were compared with bone-marrow MSCs (BM-MSCs). Lastly, whether CESCs are a suitable candidate for BM-MSCs was evaluated. Isolated cells from degenerated human CEP were seeded in an agarose suspension culture system to screen the proliferative cell clusters. Cell clusters were chosen and expanded in vitro and were compared with BM-MSCs derived from the same patient. The morphology, proliferation rate, cell cycle, immunophenotype and stem cell gene expression of the CESCs were similar to BM-MSCs. In addition, the CESCs could be induced into osteoblasts, adipocytes, chondrocytes, and are superior to BM-MSCs in terms of osteogenesis and chondrogenesis. This study is first to demonstrate the presence of stem cells in the human degenerated CEP. These results may improve our understanding of intervertebral disc (IVD) pathophysiology and the degeneration process, and could provide cell candidates for cell-based regenerative medicine and tissue engineering.
PLoS ONE 10/2011; 6(10):e26285. DOI:10.1371/journal.pone.0026285 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Advancement in tissue engineering provides a promising approach to recover the functionality of the degenerated intervertebral disc. In our study, a nucleus pulposus (NP) cell-seeded collagen II/hyaluronan/chondroitin-6-sulfate (CII/HyA/CS) tri-copolymer construct was implanted into the disc space directly after nucleotomy in a rabbit model.
The aim of this study was to investigate whether the NP cell-seeded CII/HyA/CS tri-copolymer constructs could regenerate the degenerated disc in vivo after implantation into the rabbit nucleotomy model.
Nucleotomy is one of the most prevalent surgical modalities to treat degenerative disc disease, which could achieve good short-term effects of pain relieve, whereas removal of the entire or partial NP changes the biomechanical characteristics of the remaining disc and the adjacent vertebral segments and a series of long-term complications such as accelerated annulus and the facet joints degeneration may ensue. Therefore, it is necessary to think about possible procedures immediately after the primary nucleotomy surgery to avoid these complications.
NP cells isolated from thoracic and lumbar spines of New Zealand White rabbits of approximately 3 weeks of age and 1 kg in weight were labeled with a 5- (and-6) -carboxyflurescein diacetate succinimidyl ester (CFDA-SE) fluorescent dye and seeded within the CII/HyA/CS scaffold by a centrifugation method. After in vitro culture for 1 week, NP cell-seeded CII/HyA/CS tri-copolymer constructs were allografted into the disc defects of recipient rabbit immediately after nucleotomy of the lumbar spine. The Bradner Disc Index and the T2-weighted signal intensity index were determined using lateral plane radiographs and magnetic resonance imaging at 4, 12, and 24 weeks after the operation. Finally, the operated discs were explanted for gross morphological observation, histological evaluation, and cell viability assessment. Animals with only nucleotomy and cell-free CII/HyA/CS scaffold implantation served as controls.
In our study, we could demonstrate that the T2-weighted signal intensity index of the operated discs decreased in all three groups 1 month after surgery and the index of the cell-containing scaffold insertion group was significantly higher than that of the other two groups. After 24 weeks, the index of the cell-containing scaffold insertion group increased significantly. However, further decline was observed in both the noninsertion group and the scaffold insertion group. In radiographic analysis, the narrowing of the intervertebral disc space was significantly retarded by the cell-scaffold hybrids implantation up to 24 postoperative weeks. Furthermore, the gross morphology and histological evaluation indicated that the allografted NP cells were viable and showed extracellular matrix production.
In our study, we had constructed rabbit NP cell-seeded CII/HyA/CS tri-copolymer implants in vitro. Immediately after nucleotomy of the recipient rabbit, we allografted the precultured cell-scaffold hybrids into the lacuna of the disc. Results documented survival of the allografted NP cells and extracellular matrix deposition, which finally resulted in maintenance of disc height and restoration of T2-weighted signal intensity on magnetic resonance imaging.
[Show abstract][Hide abstract] ABSTRACT: To investigate risks and clinical effects of operative treatment for cervical vertebral fracture and dislocation associated with unilateral vertebral artery injury.
This group consisted of 76 cases of closed cervical spine trauma combined with unilateral vertebral artery injury (23 cases of bilateral facet dislocation, 28 unilateral facet dislocation and 25 fracture). All patients underwent prospective examination of cervical spine MRI and vertebral artery two-dimensional time-of-flight (2D TOF) magnetic resonance angiography (MRA), and anterior cervical decompression. The healthy vertebral artery paths were evaluated before the surgery, and were protected during the surgery according to the anatomical signs.
There were no acute or chronic clinical damage symptoms in 76 cases after surgery. No neural damage symptoms were observed in patients with normal neural functions. The neural functions of incomplete paralyzed patients were improved in different grades.
Reliable anterior operation can produce good results for cervical fracture and dislocation with unilateral vertebral artery injury. Detecting the course of uninjured vertebral artery before operation and locating the anatomical site during operation are effective to avoid damaging vertebral artery of uninjured side.
Chinese Journal of Traumatology (English Edition) 10/2010; 13(5):279-83. DOI:10.3760/cma.j.issn.1008-1275.2010.05.005
[Show abstract][Hide abstract] ABSTRACT: In pedicle screw fixation, the heads of monoaxial screws need to be directed in the same straight line to accommodate the rod placement by backing out during operation, which decreases the insertional torque and internal fixation strength. While polyaxial screws facilitate the assembly of the connecting rod, but its ball-in-cup locking mechanism reduces the static compressive bending yield strength as compared with monoaxial screws. Our study aimed to assess the mechanical performance of a modified pedicle screw.
In this study, the tail of the screw body of the modified pedicle screw was designed to be a cylinder-shaped structure that well matched the inner wall of the screw head and the screw head only rotated around the cyclinder. Monoaxial screws, modified screws and polyaxial screws were respectively assembled into 3 groups of vertebrectomy models simulated by ultra high molecular weight polyethylene (UHMWPE) blocks. This model was developed according to a standard for destructive mechanical testing published by the American Society for Testing Materials (ASTM F1717-04). Each screw design had 6 subgroups, including 3 for static tension, load compression and torsion tests, and the rest for dynamic compression tests. In dynamic tests, the cyclic loads were 25%, 50%, and 75% of the compressive bending ultimate loads respectively. Yield load, yield ultimate load, yield stiffness, torsional stiffness, cycles to failure and modes of failure for the 3 types of screws were recorded. The results of modified screws were compared with those of monoaxial and polyaxial screws.
In static tests, results of bending stiffness, yield load, yield torque and torsional stiffness indicated no significant differences between the modified and monoaxial screws (P > 0.05), but both differed significantly from those of polyaxial screws (P < 0.05). In dynamic compression tests, both modified and monoaxial screws showed failures that occurred at the insertion point of screw body into the UHMWPE block, while the polyaxial screw group showed screw body swung up and down the screw head because of loosening of the ball-in-cup mechanism.
The modified screw is well-designed and biomechanically improved. And it can provide sufficient stability for segment fixation as monoaxial screws.
Chinese Journal of Traumatology (English Edition) 08/2010; 13(4):222-8. DOI:10.3760/cma.j.issn.1008-1275.2010.04.006
[Show abstract][Hide abstract] ABSTRACT: To prospectively evaluate the feasibility, safety and efficacy of the percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system in the retrospective non-randomized case-control study.
A total of 38 consecutive non-randomized patients with type A thoracolumbar fractures, which had been stabilized posteriorly from December 2006 to March 2009, were examined retrospectively more than 9 months after surgery. Twenty-one patients had been treated conventionally with open pedicle screw fixation (OPSF) and 17 patients received minimally invasive treatment with Sextant percutaneous pedicle screw fixation (SPPSF). As a method of evaluation, the incision size, the intraoperation and postoperative volume of blood loss, operation time, postoperative hospital stay, blood transfusion, the radiological assessment of the sagittal Cobb;s angle, vertebral body angle and vertebral body height were recorded and compared.
All patients were followed up for 8-24 months (average 11.6 months). There were significant differences in the incision size, surgical blood loss, surgical draining loss, operation time, hospital stay after operation, blood transfusion, the proportion of antalgic supplement and postoperative incisional VAS between the two groups (P less than 0.05). Mean preoperative kyphotic deformity was 16.0 degree and improved by 9.3 degree after surgery in OPSF group, but 15.2 degree and 10.3 degree respectively in SPPSF group. Mean preoperative angle of the fractured vertebral body was 15.9 degree and improved by 7.9 degree after surgery in OPSF group, but 14.9 degree and 6.6 degree respectively in SPPSF group. Mean anterior vertebral body height (% of normal) was 67.3% before surgery and 95.8% after surgery, but 69.1% and 90.1% respectively in SPPSF group. Mean posterior vertebral body height (% of normal) was 93.3% before surgery and 99.5% after surgery, but 88.9% and 93.3% respectively in SPPSF group. Among the patients whose 9-month follow-up films were available, 3.0 degree of kyphosis correction was lost in OPSF group, but 3.2 degree in SPPSF group. And 1.0 degree of the angle of the fractured vertebral body correction was lost in OPSF group, but 1.5 degree in SPPSF group. Then 3.0% of the anterior vertebral body height correction was lost in OPSF group, but 2.2% in SPPSF group. And 3.0% of the posterior vertebral body height correction was lost in OPSF group, but 2.5% in SPPSF group. The sagittal Cobb's angle, vertebral body angle and anterior height of the fractured vertebra were all significantly different in each group before and after operation (P less than 0.05). There were no significant differences in the postoperative sagittal Cobb's angle, vertebral body angle and the improvement of the vertebral body height and the kyphotic deformity correction between OPSF and SPPSF groups (P larger than 0.05), but there was significant difference in the postoperative anterior height of the fractured vertebra between the two groups (P less than 0.05).
The percutaneous pedicle screw fixation through the pedicle of fractured vertebra using Sextant system is a good minimally-invasive surgical therapeutic choice for patients with type A thoracolumbar fracture except for that the SPPSF has a little insufficiency in resuming the anterior height of the fractured vertebra compared with OPSF.
Chinese Journal of Traumatology (English Edition) 06/2010; 13(3):137-45. DOI:10.3760/cma.j.issn.1008-1275.2010.03.002
[Show abstract][Hide abstract] ABSTRACT: This study aims to investigate the bioactivity of collagen II/hyaluronan/chondroitin-6-sulfate tri-copolymer as bionic scaffold for nucleus pulposus (NP) tissue engineering. Collagen II (C II) (pH 1-2) was mixed with hyaluronan (HyA) and lyophilized to prepare C II/HyA matrices. Chondroitin 6-sulfate (6-CS) was covalently attached to the C II/HyA matrices using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Then, cells were expanded from rabbit NP and seeded in the tri-copolymer scaffold. Cell-scaffold hybrids were maintained for up to 28 days in culture. Cell viability/proliferation, extracellular matrix (ECM)-related gene expression, and the content of sulfated glycosaminoglycans (s-GAG) were evaluated. Our results are as following: when cultured for 28 days, the cell-scaffold hybrids maintained active cell viability/proliferation and exhibited a significantly increased s-GAG content. In addition, rabbit NP cells cultured in the scaffold demonstrated a significantly higher level of C II and aggrecan gene expression and a significantly lower level of Collagen I (C I) gene expression when compared with that of monolayer cells. Histological studies and scanning electron microscopy (SEM) further indicated newly secreted ECM deposits in the scaffolds. In conclusion, the C II/HyA-CS scaffold may be an alternative material for NP tissue engineering due to its satisfactory bioactivity, and it deserves further in vivo investigation.
Journal of Biomedical Materials Research Part B Applied Biomaterials 11/2009; 92(2):322-31. DOI:10.1002/jbm.b.31518 · 2.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To construct a novel scaffold for nucleus pulposus (NP) tissue engineering, The porous type II collagen (CII)/hyaluronate (HyA)-chondroitin-6-sulfate (6-CS) scaffold was prepared using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS) cross-linking system. The physico-chemical properties and biocompatibility of CII/HyA-CS scaffolds were evaluated. The results suggested CII/HyA-CS scaffolds have a highly porous structure (porosity: 94.8 +/- 1.5%), high water-binding capacity (79.2 +/- 2.8%) and significantly improved mechanical stability by EDC/NHS crosslinking (denaturation temperature: 74.6 +/- 1.8 and 58.1 +/- 2.6 degrees C, respectively, for the crosslinked scaffolds and the non-crosslinked; collagenase degradation rate: 39.5 +/- 3.4 and 63.5 +/- 2.0%, respectively, for the crosslinked scaffolds and the non-crosslinked). The CII/HyA-CS scaffolds also showed satisfactory cytocompatibility and histocompatibility as well as low immunogenicity. These results indicate CII/HyA-CS scaffolds may be an alternative material for NP tissue engineering due to the similarity of its composition and physico-chemical properties to those of the extracellular matrices (ECM) of native NP.
Journal of Materials Science Materials in Medicine 09/2009; 21(2):741-51. DOI:10.1007/s10856-009-3871-5 · 2.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the efficacy of microendoscopic discectomy (MED) for the treatment of lumbar disc herniation over a five-year follow-up period.
Between January 2000 and December 2002, 275 patients were accepted for MED in our hospital. A retrospective review was carried out on 151 of these cases with a mean of five years follow-up. The study helped us to assess the efficacy of this technique in the treatment of lumbar disc diseases. Modified MacNab criteria were used to assess the clinical outcome, and the disc-height ratio was assessed radiographically according to the Mochida's method.
According to the modified MacNab criteria, 78.8% of patients were rated as excellent, 13.2% as good, 4.6% as fair, and 3.3% as poor. Complications included five revision surgeries due to recurrence of herniation, five dural lacerations during operation, and three cases of vertebral/disc infection. The average disc-height ratio was 76.25%. Approximately 57% of the patients maintained their primary engagement.
MED is both feasible and efficacious for the management of lumbar disc disease. On the basis of the present study it is concluded that MED is better than open discectomy (OD).
Orthopaedic Surgery 08/2009; 1(3):171-5. DOI:10.1111/j.1757-7861.2009.00039.x
[Show abstract][Hide abstract] ABSTRACT: Primary non-Hodgkin lymphoma (PHL) of the spine is very rare. A case of a 44-year-old patient with PHL originating from a single lumbar vertebra was initially misdiagnosed as tuberculous spondylitis. After surgical decompression and biopsy, the patient was confirmed as primary B-cell non-Hodgkin lymphoma of the lumbar vertebrae and was further treated with chemotherapy. It warrants attention that PHL from the spine may be misdiagnosed as tuberculous spondylitis.
Archives of Orthopaedic and Trauma Surgery 03/2009; 129(12):1621-5. DOI:10.1007/s00402-009-0835-7 · 1.60 Impact Factor