Tongwei Chu

Utilization of stem cells in alginate for nucleus pulposus tissue engineering.

In a general view of anatomy, intervertebral disc 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 bone marrow (BM)-mesenchymal stem cells (MSCs) in a rabbit disc degeneration model. By magnetic resonance imaging (MRI), X-ray, histology, etc. evaluations, we found that cartilage endplate-derived stem cells (CESCs) showed superior capacity compared with the annulus fibrosus-derived stem cells (AFSCs), nucleus pulposus-derived stem cells (NPSCs), and BM-MSCs (p<0.05); additionally, when comparing the CESC group with the normal control group, there existed no statistical difference in X-ray (p>0.05). Those results demonstrated that the CESC-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.

Acute traumatic cervical cord injury in patients with os odontoideum

We retrospectively reviewed acute cervical cord injury after minor trauma in 10 patients with os odontoideum. Their clinical history, neurological symptoms, radiological investigations, follow-up period, American Spinal Injury Association impairment classification and motor score were reviewed. Before their traumatic injury, three patients were asymptomatic and seven reported myelopathic symptoms, including four patients with neck pain, two patients with unsteadiness and one patient with dizziness. Falls were the most common cause of injury (n=6), followed by minor motor vehicle accidents (n=3) and assault (n=1). MRI and dynamic cervical lateral radiographs showed that all patients had atlantoaxial instability and cord compression. Most patients had spinal cord thinning and hyperintensity on T2-weighted MRI. Spinal cord compression was posterior (n=5), or both anterior and posterior (n=5). All patients underwent posterior rigid screw fixation and fusion, including atlantoaxial fusion (n=8) and occipitocervical fusion (n=2). We conclude that patients with asymptomatic or myelopathic atlantoaxial instability secondary to os odontoideum are at risk for acute spinal cord injury after minor traumatic injury. Fixation and fusion should be undertaken as prophylactic treatment for patients at risk of developing myelopathy and to avoid the neurological deterioration associated with acute traumatic cervical cord injury.

Cells scaffold complex for Intervertebral disc Anulus Fibrosus tissue engineering: in vitro culture and product analysis

The study was designed to investigate feasibility of tissue culture in vitro utilizing static culture method. Annulus fibrosus cells obtained from spine of rabbits were cultured. Results showed that fibrous tissue infiltration could be detected in shallow layer. With extended time, tissue infiltration depth increased, but there were still a large amount of holes in central part. Fibrous tissue infiltration was detected in the control side products and inner infiltration wasn’t obvious. Hydroxyproline content of the control side products gradually increased with extended culture time. Hydroxyproline content of the control side products in the third and fourth month was significantly higher than that in the first month, but lower than those of the experimental side products and normal annulus fibrosus cells. DNA content of the control side products in the third and fourth month was significantly increased compared to the first month. DNA content of the control side products at each phase point was significantly lower than that of the experimental side and normal annulus fibrosus cells. Furthermore, there was lower expression levels of the type I, II collagen mRNA and protein in the experimental side scaffolds compared to the control side product. This study demonstrates the successful formation of Intervertebral disc Anulus Fibrosus in vitro by static culture method.

Effect of vascular endothelial growth factor 121 adenovirus transduction in rabbit model of femur head necrosis.

BACKGROUND Our objective was to observe the role of vascular endothelial growth factor (VEGF) 121 gene transfer in promoting vascular reconstruction and bone repair in femur head necrosis of rabbits. METHODS The femoral head necrosis model was induced by injection with ethanol. The necrotic femoral head was transfected with a human adenoviral vector expressing VEGF (Ad-hVEGF121). Bone formation in the subchondral necrotic region was analyzed using histology, by measuring the bone mineral density value, and by observing bone trabecular morphology using image analysis. RESULTS Revascularization level, bone formation rate, bone quality and quantity, and mineralization level in the subchondral necrotic region of the gene transfection group were significantly higher than the control groups. The control groups had more subchondral bone resorption compared with the gene transfection group. CONCLUSION VEGF might promote bone formation and revascularization in the subchondral necrotic region of the femoral head, indirectly protecting the necrotic bone trabecula from absorption and avoiding a reduction in the mechanical function of the subchondral region.

Sustained Vascular Endothelial Growth Factor Blockade by Antivascular Endothelial Growth Factor Antibodies Results in Nonunion in the Process of Fracture Healing in Rabbits

OBJECTIVE To study the role of vascular endothelial growth factor (VEGF) in the process of fracture healing and the effect of VEGF and anti-VEGF polyclonal antibody on fracture healing. METHODS One hundred and five New Zealand white rabbits were subjected to fracture of the middle part of the left radius, and were randomly divided into control, VEGF, and VEGF polyclonal antibody groups. The blood flow at the fracture site was measured by single photoemission computerized tomography after 8 hours, 24 hours, and 72 hours, and 1 weeks, 3 weeks, 5 weeks, and 8 weeks. X-ray films were taken after 1 weeks, 3 weeks, 5 weeks, and 8 weeks to observe the results of fracture healing. RESULTS The blood flow at the fracture site in the VEGF group significantly increased compared with the control group during 8 hours to 1 week, but no obvious difference was seen on the X-ray films between the two groups. In the VEGF polyclonal antibody group, the blood flow at the fracture sites decreased significantly at all time points compared with the control group. The fracture healing process was disturbed, and nonunion signs were seen at the fracture site. CONCLUSIONS The lack of VEGF may impede the fracture healing process, and results in nonunion at the fracture site.

Minimally Invasive Posterior Decompression Combined With Percutaneous Pedicle Screw Fixation for the Treatment of Thoracolumbar Fractures With Neurological Deficits: A Prospective Randomized Study Versus Traditional Open Posterior Surgery.

Study Design. Prospective randomized cohort study. Objective. To compare the surgical results of minimally invasive posterior decompression combined with percutaneous pedicle screws fixation (minimally invasive surgery [MIS]) and posterior open surgery (OS) for the treatment of thoracolumbar fracture with neurological deficits. Summary of Background Data. Thoracolumbar fracture with neurological deficits usually undergoes surgical intervention. OS can achieve satisfied results, but the main disadvantage is approach-related complications. No study, however, focused on the treatment of this disease by MIS through posterior approach. Methods. Sixty consecutive cases of thoracolumbar fractures with neurological deficits were randomized into MIS group and OS group. Incision length, blood loss, postoperative drainage volume, hospitalization days, blood transfusion rate, analgesic use rate, and x-ray exposure time were used to evaluate the perioperative information and Visual Analog Scale (VAS), Japanese Orthopedics Association (JOA) score, and American Spinal Injury Association grade for patients’ symptom. For radiological assessment, sagittal Cobb angle, percentage of vertebral height, and vertebral wedging angle were measured. Results. Fifty-nine of sixty patients were followed-up for at least 12 months. MIS group was superior in perioperative information (P < 0.05), except in the operative time (P = 0.165) and x-ray time (P = 0.000). The operative time seemed longer in MIS group, but no significant difference was found. The x-ray time was significantly higher in MIS group. The mean Visual Analog Scale and Japanese Orthopedics Association scores of the final follow-up in MIS group were better than that in OS group (P < 0.05). Patients in both group achieved a similar neurological recovery according to American Spinal Injury Association grade (P = 0.760). A broken screw was found in one patient in MIS group and a broken rod in one patient in OS group. Conclusion. MIS group has achieved the similar effect of OS group and it can minimize the approach-related complication. It also faced with some shortages, such as larger radiation dose and longer learning curve. Level of Evidence: 2

Histopathological changes in supraspinous ligaments, ligamentum flava and paraspinal muscle tissues of patients with ankylosing spondylitis

To examine the histopathological changes in spinal tissues of ankylosing spondylitis (AS) patients.

Minimally invasive strategies and options for far-lateral lumbar disc herniation.

OBJECTIVE To investigate the surgical procedures, options and surgical indications for far-lateral lumbar disc herniation between three different minimally invasive procedures. METHODS From January 2000 to October 2006, 52 patients with far-lateral lumbar disc herniation (29 males and 23 females, with the average age of 41.5 years) were treated with minimally invasive procedures. All the patients were assessed by X-ray and CT. Some were given additional myeography, discography, Computerized tomography mye-lography (CTM) and MRI examination. Yeung Endoscopy Spine System (YESS), METRx and X-tube procedures were performed in 25, 13 and 14 cases, respectively. All patients were followed up for a mean period of 13.5 months. Clinical outcomes were assessed by visual analog score (VAS) and Nakai criteria. RESULTS The results indicated that the three procedures could significantly improve the radiating leg symptoms (P less than 0.05). The postoperative overall excellent and good rates of YESS, METRx and X-tube procedures were 84.0%, 84.6% and 92.8% respectively, with no statistical difference among three groups (P larger than 0.05). The YESS procedure had several advantages including shortest operation time, simplest anesthesia and least trauma as compared with the other two procedures, especially for simple type I far-lateral lumbar disc herniation. METRx procedure was specially suitable for simple type II. And the procedure of posterior endoscopic facetectomy, posterior lumbar interbody fusion and unilateral pedicle screw instrumentation with X-tube was designed for far-lateral disc herniation combined with degenerative lumbar instability. CONCLUSION Minimally invasive strategies and options should be determined by different types of far-lateral lumbar disc herniation.

Cervical Disk Replacement Combined With Cage Fusion for the Treatment of Multilevel Cervical Disk Herniation.

Study Design:This is a prospective study of artificial disk replacement combined with cage fusion for the treatment of multilevel cervical disk herniation. Objective:To evaluate the clinical outcome of Bryan cervical disk replacement combined with adjacent segment cage fusion in the treatment of patients with multilevel cervical disk herniation. To observe neurological improvement and interpret the radiographic findings. Summary of Background Data:It is generally considered that 1-level cervical disk replacement had an excellent intermediate clinical outcome. There was no final conclusion about the disk replacement for the treatment of multilevel cervical disk disease. The negative factors include possible complication, high cost, and contraindication for disk replacement at one of the multisegments. Disk replacement combined with adjacent segment cage fusion may be an option for the treatment of multilevel cervical disk disease for certain patients. Methods:There were 26 patients with multilevel cervical disk herniation who underwent 1-level disk replacement and adjacent segment cage fusion. Of the patients, there were 17 male and 9 female, aged between 35 and 63 (mean age 47 y). The herniated disk was located at C3–C4, C4–C5 in 1 case, C4–C5, C5–C6 in 11cases, C5–C6, C6–C7 in 7 cases, C4–C5, C6–C7 in 3 cases, and C4–C5, C5–C6, C6–C7 in 4 cases. There were 12 cases with myelopathy and 14 patients with radiculopathy. The stabilization and the range of motion of implanted disk, the fusion of cage, and the displacement of cage were observed on dynamic radiograph postoperatively. The clinical symptoms and the neurological functions were evaluated based on the Japanese Orthopaedic Association Scale score (17 points), neck disability index score, and Odom’s Criteria. Results:All patients underwent 1-level Bryan disk replacement and cage fusion on adjacent segment. The replacement segment and fusion segment were located next to each other among 23 patients. They were not next to each other in 3 cases. The follow-up was 24 to 47 months. Definite stabilization was achieved for all Bryan disks. The average range of motion at replaced level was 9.5 degrees postoperatively. Solid fusion was achieved in all cages. There was no subsidence or displacement of cage. The Japanese Orthopaedic Association Scale score (17 points) rose from 9.2 to 13.5 at final follow-up. The neck disability index was reduced from 40.8 to 28.5 at final follow-up. The clinical success (excellent/good/fair) based on Odom’s Criteria were 84.6%. Conclusions:Definite stabilization and satisfactory mobility were achieved after cervical disk replacement and cage fusion. This provides an effective option for the treatment of multilevel cervical disk herniation. The evaluation of high fusion rate of cage may need to accumulate more clinical cases.

Clinical experience and results of lumbar microendoscopic discectomy: a study with a five-year follow-up

Objective:  To investigate the efficacy of microendoscopic discectomy (MED) for the treatment of lumbar disc herniation over a five‐year follow‐up period.