With deeper understanding for intervertebral disc degeneration,the development and clinical application of protocols in molecular biology,biological intervention in initial stage of intervertebral disc degeneration can retard even reverse the degeneration process. Gene therapy of intervertebral disc degeneration refers to the selection of animal models and gene carriers,application of target genes,etc. It is the key for gene therapy to build human-like animal model,select proper gene carrier and apply ideal target genes. Prior to clinical application,the safety and efficacy of gene therapy should be proved,thus many problems deserve further study.

The fracture dislocation of axis is a common kind of severe trauma.Because of particular anatomic characteristics of axis, the operation is difficult and highly risky. However, with introduction of new instrumentation and improvement of surgical techniques, innovative methods have been developed in recent years, including posterior C1-2 fusion and internal fixation, decompression by the dissection of C1 posterior arch, occipitocervical fusion and internal fixation, anterior internal fixation for dens fracture dislocation, anterior decompression and internal fixation for vertebral arch fracture dislocation. The available instruments include interlaminar clamp, rod or plate, screw, etc. All these methods and instruments have their respective advantages and disadvantages and indications. In this paper, The indications, effects, and potential complications of them are discussed.

Objective To study the effects of direct-current field stimulation on spinal cord motor neurons apoptosis after sciatic nerves transection. Methods In experimental group direct-current stimula tors were put into the relevant spinal cord segments and electric stimulation were given instantly after sciatic nervet ransection.In control group, the same st I mulator were put inside without courrent output.The spinal cord specimens were taken 1，4，7，14，28 days after operation. The morphology of the spinal cord motor neurons was observed with the methods of HE staining and light microscope.The spinal cord motor neurons were counted and analyzed with three-dimensional quantit ative method.The TUNEL staining of the specimens was performed simultaneously and the positive-stain spinal cord motor ne u rons were counted. Results 4，7，1 4 and 28 days af ter operation, the number of spinal cord motor neurons and the size of the neurons increased obviously with compare to the control group.The TUNEL staining positive spinalcord motor neurons decreased sign I ficantly according to the control group. Conclusion Direct-current stimu lation may have intervention effects on spinal cord neuron apoptosis after sciatic nerve transection.

BACKGROUND: The establishment of animal models is of important significance for understanding the pathogenesis, prevention, and treatment of intervertebral disc degeneration. OBJECTIVE: To develop rabbit models of intervertebral disc degeneration by acupuncture and to analyze the effects of acupuncture on intervertebral disc height and degeneration by X-ray and MRI examinations. DESIGN: A randomized and controlled observation. SETTING: Department of Orthopaedics, Changhai Hospital, Second Military Medical University of Chinese PLA. MATERIALS: This study was performed at the Animal Cener, Changhai Hospital, Second Military Medical University of Chonese PLA between June 2005 and April 2006. Six healthy New Zealand white rabbits of either gender, averaging 6 months old, weighing 2.5 kg on average, were provided by Animal Cener, Changhai Hospital, Second Military Medical University of Chinese PLA [permission No. SCXK (hu) 2002-0006], and recruited for this study. The protocol was performed in accordance with ethical guidelines for the use and care of animals.METHODS: ① Operation was made in experimental rabbits via the anterior retroperitoneal approach. The management for the intervertebral discs was as follows: L3-4 was the control disc without exposure or needle stab; L4-5 was subjected to sham-operation with only exposure; L5-6 was the experimental disc with three times of anterior-lateral needle stab after exposure. Lumbar lateral X-ray film was respectively taken with a CR machine (Simens Company) prior to and 4 weeks after surgery for measuring L3-4, L4-5, and L5-6 intervertebral disc height and calculating the ratio with intervertebral disc height prior to surgery. Each segmental lumbar intervertebral disc T2-weighted signal was measured with a 1.5 T medical superconductive magnetic resonance scanner (Simens Avanto). According to signal intensity, intervertebral disc degeneration was graded: a score of 4 indicated normal intervertebral disc without apparent degeneration but with bright signal, a score of 3 indicated slight degeneration with a little decrease in T2-weighted signal, a score of 2 indicated moderate degeneration with apparent decrease in T2-weighted signal, and a score of 1 indicated severe degeneration with apparent decrease in both T2-weighted signal and intervertebral disc height. MAIN OUTCOME MEASURES: Intervertebral disc height change revealed by lumbar lateral X-ray film; Intervertebral disc degeneration degree analyzed through magnetic resonance imaging (MRI) examination. RESULTS: All 6 experimental rabbits were included in the final analysis. The postsurgery-to-presurgery ratio of intervertebral disc height was 0.982 5±0.017 08 and 0.972 5±0.017 08 for L3-4 and L4-5 respectively, which was higher compared to that for L5-6 (0.550 0±0.02 582). Significant statistical difference existed (P ＜ 0.01). T2-weighted singal score was (4.00±0.0) and (3.75±0.5) for L3-4 and L4-5 intervertebral disc, respectively, which was higher compared to that for L5-6 intervertebral disc. Significant statistical difference existed (P ＜ 0.01). CONCLUSION: After 4 weeks of acupuncture, intervertebral disc height is decreased and interterbral disc degeneration obviously appears.

AIM:In human being,the exposure of lumbar Intervertebral discs usually requires the anterior transperitoneal or lateral retroperitoneal approaches. To study the feasibility of retropedtoneal approach to the lumbar spine in the New Zealand white rabbits.METHODS: The experiment was carried out between April 2005 and April 2006 in the Animal Center of Changhai Hospital.Second Military Medical University of Chinese PLA.Thirty New Zealand white rabbits,aged 6 months old, of either gender, weighing 2.5 kg,provided by the Animal Center of Changhai Hospital,Second Military Medical University of Chinese PLA [permission No.SCXK (hu) 2002-0006],were used in this study.During the experiment,the management of animals corresponded to Animal Ethical Standard.This study was approved by the Experimental Animal Ethics Committee,Changhai Hospital,Second Military Medical University of Chinese PLA.Transperitoneal approach was used to exposure the lumbar spine of experimental rabbits. The skin was disassociated, and a blunt dissection was made backwardly along the juncture of the maximum back muscle and external oblique muscle of abdomen,and lumbar intervertebral disc was exposed gradually.Observation index:①Operative effect of exposure.②Postoperative general condition (food intake,urination and defecation,activity,incision healing and death or not).RESULTS: Thirty experimental rabbits were involved in the final analysis.①The operative effect of exposure:The dght retroperitoneal approach was chosen,with satisfactory anesthesia and excellent exposure of rabbit lateral lumbar spine. And the exposure was usually accomplished within 15 minutes, with Less bleeding and no retroperitoneal rupture. ②Postoperative general condition: All animals recovered their consciousnesses within about 1 hour. They were intravenously injected continuously for supplementing blood volume,and after that,they were raised in the separate cases and were allowed to move freeLy.On the day of operation.they were fasted and forbidden to access to water.Their appetites began to decrease on the postoperative 1 day.restored from the 3rd day postoperatively and restored to normal on the 40th day postoperatively.All animals survived until after 4 weeks.They could move freely,without paralysis occurred or incontinence. There was one experimental animal whose surgical Incision broke.Debridement and resuture were given, and its wound healed. In all the other animals, the surgical incision healed well.CONCLUSION: Retroperitoneal approach can give an excellent access to the lumbar spine with easy operation and less complications.

[Objective]To investigate the operation indications and techniques of the ISOLA spinal system in reconstruction of the lumber-pelvis continuity after resection of high-level sacral tumors. [Method]A retrospective study was performed in 43 patients with high-level sacral tumor (HLST) between July 2001 to January 2007. Symptoms, signs, histological findings of the tumors and their outcomes were analyzed. All patients underwent resection of HLST and spinopelvic reconstruction with ISOLA spinal system,11 unilateral and 32 bilateral.[Result]Among the 43 patients, 33(77.1%)had chordoma, giant cell tumor of bone and neurogenic tumors. Thirty-four patients alive were followed-up for an average of 35 months(12~62 months), 5 patients had a recurrence of chordoma and 29 patients with HLST were under control. The pain originated from the lumbosacral joint and the spinal nerve root was obviously relieved.The patients could stand and ambulate normally. No loose screw or broken rod were found.X-rays showed no signs of the enlarged screw canal or lowered lumbar spine.The effect was 76.5%(26/34) excellent judged by the ISOLS system.[Conclusion]Spinopelvic reconstruction by ISOLA system after resection of HLST is characterized by easy manipulation, less complications and instant stable fixation. It may be widely used in the clinical practice.

Objective To evaluate the results of the Secuplate anterior cervical osteosynthesis plate (SACOP) for the treatment of patient with cervical spondylotic myelopathy (CSM). Methods Twenty six patients with CSM underwent anterior decompression fusion and internal fixation with SACOP were reviewed. All patients were followed up for 6 to 12 months (mean, 8 months). Results Neurological deficits improved in 23 of 26 patients after operation. A stable bony fusion according to radiological criteria was achieved in all cases 6 months postoperatively. There was no implants breakage and loosening. Conclusion Intervertebral fusion and internal fixation with SACOP after anterior decompression can offer immediate stability, prevent graft dislodgement, avoid cast immobilization and give a high rate of successful bony fusion for the patient with CSM.

To study the protective effects and the mechanism of drugs on apoptosic neural cells after spinal cord injury and the mechanism of their effects on severe degree compression injury to the lower thoracic spinal cord (T 8.9). Rats were divided into four groups randomly . The first group of rats were treated with saline solution(20?l) intrathecally after injury, the second group with cyceoheximide (CH)(30?g/20?l) intrathecally, the third group with monosialicganglioside(GM)(100?g/20?l),and the fourth group methylprednisolone(MP)(30mg/kg). The changes in weight, spinal cord blood flow(SCBF), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL),neurological function and quantitative histological changes were observed.The results indicated that drugs had little effects on the SCBF. But drugs could improve the neurological function and area of spared normal tissue, and obviously reduce the number of TUNEL-positive cells. The results suggested that drugs had neuroprotective effects on the injuried spinal cord. The mechanism of the beneficial effects might be a reduction in neuronal cells apoptosis.

To study the effect of hyperbaric oxygen (HBO) on the activity of superoxygen dismutase (SOD) and catalase (CAT) in spinal cord tissue, a rat spinal cord injury (SCI) model was established. The results showed that the activity of SOD and CAT in the spinal cord decreased significantly after injury, bat recovered after the treatment with 0 25MPa HBO and 0 25MPa HBO+hormone. These results suggest that HBO can increase the activity of anti oxidase in spinal cord,and prevent or relieve the injury by free radicals. Thus it can recover the function of spinal cord.

To study the mechanism of hyperbaric oxygen (HBO) on spinal cord injury (SCI), we duplicated a SCI model and determined the concentrations of excitatory amino acids [EAA, including aspartic acid (Asp) and glutamic acid (Glu)] in spinal cord tissue after treated with 0 1 MPa HBO, 0 25 MPa HBO, 0 25 MPa N 2 O 2 and hormone, respectively. The results showed that the concentration of EAA (Glu) in the spinal cord significantly increased after injury, whereas after treatment it decreased in all but the N 2 O 2 group. It decreased most significantly in 0 25MPa HBO and 0 25MPa HBO+hormone groups. There were significant differences between 0 25MPa HBO group and 0 1MPa HBO group, 0 25MPa HBO+hormone group and pure hormone group ( P