From sep. 1990. through Nov. 1990, we introdused a new technique in anterior cervical fusion. It reserved the bone dowel taken by trephine on the intervertebral levels, after decompression, rotated and inserted the dowel in initial hole, then placed a Ti Ni sharp memory alloy expansion screw into the dowel. Expansion force of the screw could exert continuous compression force on the bone graft, and made the graft tight contact with bilateral side of the vertebra. We treated 12 cases, 8 of them were cervical trauma (fractures, subluxations or a combination of these disorders), 4 were cervical spondylotie myelopathy. All cases obtained solid fusion and stability was achieved immediately after surgery. There was no graft dislodgement or deformity. None of the screws were loosened. We conclude that this method can prevent the graft displacement, promote the healing process, only need shortly immobility postopertively and allow early rehabilitation. It need not take iliae graft, and can aviods the donor site complicatons.

Objective: To compare the biomechanical strength of tension band with cancellous bone screws with AO tension band,modified tension band and cancellous screws alone for the treatment of patella fracture.Methods:20 fresh frozen cadaveric knee specimen were divided into four groups randomly.Transverse osteotomies of the patella were performed and the simulated fractures were fixed with four techniques.The biomechanical testing was perfomed by using WD-10E electrical mechanical testing machine.The internal fixation was considered failure when fracture gap exceeding 1mm.Results:All techniques functioned adepuately under 420 N loading of quadriceps tendon.However,biomechanical strength was greatest in tension band with cancellous bone screws (P＜0.05)，lowest in AO tension bands and no stability enough in cancellous bone screw alone.Conclusion:Tension band with cancellous bone screws is the best technique for the treatment of patella fracture.

[Objective]To observe the growth pattern of oligodendrocyte precursor cells(OPCs) in the primary culture from neonatal rat cerebral cortices and study the methods of cell culture and isolation in order to obtain purified OPCs for the experiments of cell transplantation.[Method]The mixed glial cells from the cerebral cortices of 48-hour-old Sprague-Dawley(SD) rats were cultured in vitro.Until 9-10 days in vitro OPCs were isolated and purified by the shaking process and differential adhesion,and then continued OPCs culture in the defined medium.The growth pattern of OPCs in vitro was investigated by contrast phase microscopy and OPC s were further identified with the immunocytochemical techniques.[Result]The distinct stratification of OPCs and astrocytes developed around 9-10 days in primary culture.At this point,the OPCs scattered on the top of the monolayer astroctyes and the soma of most OPCs typically appeared oval or round with two or three processes.The purity of the isolated OPCs reached 95% and these OPCs further developed into the mature oligdendrocytes which were immunoreactive to the specific antigen of oligodendrocyte lineage cells,Oligo2.[Conclusion]OPCs separated from the cerebral cortices of neonatal SD rats can be maintained as immature precursor cells in culture,and OPCs are able to be purified by shaking and differential adhesion under the condition of appropriate cell stratification.

[Objective]Using a procedure of chemical agent to remove the cells and myethin in spinal cord of rat and to prepare the scaffold of extracellular matrix,so as to obtain an ideal natural spinal cord scaffold to bridge the nerve gap.[Method]Rat spinal cord was cut and treated using the method of freeze thawing and chemical extraction(3%sodiumdeoxycholate and 1KU/ml DNaseI,RNaseA).Histology was exploited to evaluate the degree of acellular and the structure of the spinal cord scaffold.[Result]In cross section,network of the extracellular matrix was presented in the scaffold.The cells,myethin and axons disappeared after the spinal cord was treated with sodium deoxycholate and DNaseI,RNaseA.Typical network of empty tubes were viewed in longitudinal sections.[Conclusion]An ideal spinal cord scaffold can be produced with the method designed in authors experiment.This scaffold has similar three dimensional structure with normal spinal cord,which can be used as a graft to bridge the nerve gap directly or as a scaffold to implant the seeding cells in spinal cord tissue engineering.The experiment indicates that cells and myethin can be removed and the three dimensional structure be reserved by chemical extraction with 3% sodium deoxycholate and 1KU/ml DNaseI,RNaseA.Chemical extraction is an ideal method to prepare tissue engineer scaffold of spinal cord.

[Objective] To investigate the immunogenicity of the acellular spinal cord scaffold and to provide theoretical basis for its further application in tissue engineering.[Method]Acellular spinal cord(freeze thawing +3%sodiumdeoxycholate + DNaseI 、RNaseA)and fresh spinal cord of rats were implanted into paravertebral muscles of rats.The tissue was obtained at 1、2、3 and 4w after the operation,then the inflammatory reaction was evaluated by HE stain and the immunogenicity of acelular scaffold was tested by immunohistochemical examination of the intensity of CD3+ 、CD4+ and CD8+ cells that infiltrated the allografts.[Result]The bistological examination indicated that acellular spinal cord scaffold was surrounded by a amount of neutrophilic cells and lymphocytes one week postoperatively,yet two weeks postoperatively,there was only small amount of lymphocytes infiltration.Fresh spinal cord allograft elicited an intense acute inflammatory infiltrate,and two weeks later,there still had a mount of lymphocytes infiltration.The intensity of CD3+、CD4+ and CD8+ T cells that infiltrated the allografts was greatly lower in acellular spinal cord than that in fresh spinal cord.The mild cell-mediated host-graft immune rejection in acellular spinal cord was observed.[Conclusion]The acellular spinal cord scaffold has mild inflammatory reaction and immune rejection,suggestting it is qualified for some biological properties and it may be a potential alternative scaffold of tissue engineering.

BACKGROUND: MRI is generally considered as an important means to diagnose cervical disc herniation.OBJECTIVE: To explore the correlation between clinical manifestations of traumatic cervical disc herniation and MRI changes.DESIGN: A retrospective study.SETTING: Department of Orthopedics, Xinqiao Hospital of Third Military Medical University of Chinese PLA.PARTICIPANTS: We selected 123 patients with traumatic cervical disc herniation who came to the Department of Orthopedics, Xinqiao Hospital of Third Military Medical University of Chinese PLA, for treatment between June 1982 and June 2002. Their clinical manifestations fell into four types:of grade Ⅰ or Ⅱ, 14 of which lost motility with normal or slightly impaired icantly decreased or lost motility of the bilateral upper limbs with myotility of nificantly decreased motility and thignesthesia of the unilateral upper and impaired motility, decreased pain sensation of the lower limb on the opposite side, but with good myotility.METHODS: MRI examination was carried out in 123 cases of traumatic cervical disc herniation.MAIN OUTCOME MEASURES: The correlation between the clinical manifestations of 123 cases and MRI results.RESULTS: The clinical manifestations and MRI information of 123 cases verse-type herniation, clinically manifested as symmetric incomplete as central canal syndrome and significantly decreased or lost motility of the ripheral-type herniation, manifested as nerve root pain of unilateral side as well as pain sensation and thermesthesia on the opposite side.CONCLUSION: MRI typing suggests the segment, position and shape of disc herniation specified, and the 4 types of clinical manifestations indicate the consistency of anatomic location with the corresponding neural disorder.

Objective To investigate the effects of transplantation of oligodendrocyte precursor cells (OPCs) on axonal myelination after spinal cord injury in a rat model. Methods A rat model of spinal cord injury at the tenth thoracic vertebral level (T10) was produced by Allen weight-drop impact method. OPCs implantation was performed at the subacute stage of spinal cord injury. Effects of OPCs transplantation on axonal myelination after spinal cord injury were evaluated by HE staining, immunohistochemistry, myelin staining and transmission electron microscopy. Results The implanted cells were still observed in lesioned segments of spinal cord eight weeks after transplantation. The results of HE staining clearly showed better structure of spinal cord in OPCs-transplanted group than that of control group.Myelin staining also demonstrated that the amount of myelin in white matter of lesioned cord in the OPCs-transplanted group (7 802.42 ± 1085.58) was higher than that of the control group (5 055.98 ± 916.74)(P ＜0.01 ). Expression of myelin basic protein (MBP) was significantly increased in the OPCs-trans-planted group (8 544.44 ±812.78) as compared with that of the control group (5 243.83 ±808.27)(P＜0.01). Moreover, transmission electron microscopy further confirmed the improvement of micro-structure of myelination in OPCs-treated rats. Conclusion OPCs transplantation can improve axonal myelination in rat with spinal cord injury.

Objective To evaluate the in vitro biological safety of acellular spinal cord scaffold so as to provide theoretical basis for constructing the ideal tissue engineering scaffold of spinal cord.Methods A piece of thoracic spinal cord for 2 cm removed from SD rats was harvested and then was treated by freezing and thawing and chemical extraction with 3% sodium deoxyeholate and 1 KU/ml DNaseI and RNaseA. Gross observation and histological examination of the acellular spinal cord scaffold were carried out to learn the condition of the extracellular matrix scaffold. The biological safety of the acellular spinal cord scaffold was evaluated. Results In cross section, network of the extracellular matrix was presented in the scaffold. The cells, myelin and axons disappeared after the spinal cord was treated with sodium deoxycholate, DNaseI and RNaseA. Typical network of empty tubes were viewed in longitudinal sections. General toxic reaction, pyrogen test, hemolysis test and cytotoxicity test were conforming to the standard of materials. Conclusion As neotype tissue engineering material, the acellular spinal cord scaffold has satisfactory biological safety.

[Objective]To evaluate the early-middle stage clinical results of cervical disc hemiation treatment with the Bryan cervical disc prosthesis.[Method]There were 51 patients with cervical disc herniation.There were 16 female and 35 male patients aged between 31 and 57(mean age 43).The herniated disc was located at C3、4 in 8 cases,C4、5 in 4 cases,C5、6 in 31 cases,C6、7 in 2 cases,C4～6 in 2 cases,C3～6 in 2 cases.and C5～7in 2 case.There were 16 patients with myelopathy and 31 with radiculopathy.A total of 57 sets of Bryan cervical disc prosthesis were implanted,with single level disc replaced in 45 cases and bi-level in 6 cases.The Bryan cervical disc prosthesis contained a proprietary,low-fiction,wear-resistant,unique polyurethane nucleus.The nucleus was located in shaped titanium plates(shells) that include convex porous ingrowth surfaces,to allow bony fixation to the adjacent vertebral endplates.The level of stableness and mobility at the implanting location were observed on dynamic radiograph postoperatively.[Result]The average follow-up was 1 year to 4 and half year.There was no prosthesis displacement and loosening in all cases.One patient had a definite spontaneous fusion of treated segment after 4 years of follow-up.Two patient had grade Ⅱ heterotopic ossification(HO).The range of motion(ROM) at implant level was 9.3 degrees on the flexion-extension radiographs.Significant improvement in neurological symptoms were observed in all cases,and radicular pain for patients suffering from raduculopathy was relieved completely.The average improvement was 8.5 points based on CSM criteria.Effective rate was 100%.[Conclusion]Artificial cervical discs prosthesis provides a new effective treatment for cervical disc herniation.Definite stabilization and satisfactory mobility were achieved after the implantation of cervical disc prosthesis.

0.05).Measurement results of adjacent segment movement extention showed more significant changes in the fusion group than in the non-fusion group(P