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 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.

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 study the effect on ischemic injury of cervical spinal cord(CSC) by comparison on two different blocks of arteries supplying CSC.[Method]Forty-eight rabbits were divided into two groups: Group A,ligation and section of anterior cervical spinal cord artery(ASCA);group B ligation and section of both ACSCA and bilateral vertebral arteries before its entramce the foraman(indirect block of Anterior cervical radicular artery(ACRA).Bdood flow changes of CSC were meansured after 6 h,24 h and 72 h(each N=6) and muscle motor cooked potential(MMEP),local energy metabolism,and cell morplotogical changes of CSC were observed.[Result]In group A,blood flow of CSC was going down markedly and showed 50.2% decrease,but got partial recovery at 24 h and 72 h.Delitescence of MMEP prolongcd,ATP and EC descended profressivtly,showing an ischemic changes,In group B there showed greate,changes about every observation thay that in group A with significant difference at every time poinl between two groups(P

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 compare the effect of 2 decellularizing methods,sodium deoxycholate plus Triton X-100 or plus DNase and Rnase,in the preparation of acelluar allograft spinal cord scaffold in order to provide an ideal natural spinal cord scaffold to bridge the nerve gap.Methods Spinal cord was removed from health rats,and then decellularized by the method of freeze thawing(immersing in 3% sodium deoxycholate followed by the mixture of 1?103 U/ml DNase and RNase),or by chemical extraction(immersing in 1% Triton X-100 and then 1% sodium deoxycholate).HE staining,myelin staining and scanning electron microscopy(SEM) were employed to evaluate the spinal cord scaffold after the 2 methods of decellularization.Results Both cells and myelin were completely decellularized with the 2 methods.In cross section,network of the extracellular matrix was presented without axon,sheath and cells nucleus being seen in the scaffold.Typical network of empty tubes were viewed in longitudinal sections.Conclusion An ideal spinal cord scaffold can be produced with these 2 decellularizing methods in tissue engineering.The scaffold made by the 2 methods have similar three dimensional structure with normal spinal cord,so 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.

[Objective]To evaluate the clinical result after treatment of disc herniation with the Bryan cervical disc prosthesis.[Method]There were 14 cases with cervical disc herniation.There were 4 females and 10 males with ages ranging 31~52 years(mean age 43 years).The herniated disc located at C_(3、4) in 2 cases,C_(4、5) in 2 cases,C_(5、6) in 8 cases,C_(4~6) in 1 case and C_(3~6) in 1 case.A total of 16 Bryan cervical disc prosthesis were implanted.Single level disc was replaced in 12 cases while hi-level in 2 cases.The Bryan Cervical Disc prosthesis contains a proprietary,low-friction,wear-resistant,unmique polyurethane nucleus.The nucleus was articulated with shaped titanium plates(shells)that include convex porous ingrowth surfaces,to allow bony fixation to the adjacent vertebral endplates.The stabilization and range of motion at the implanted level were observe red on dynamic radiograph postoperatively.[Result]The average follow up was 10 months and the longest follow up was 28 months.Neurological symptoms in all cases had significant improvement.The average improvement was 8.5 point according CSM criteria.Effective rate was 100%.There was no prosthesis displacement and loosening in all cases.The ROM at implant level was 6.4 degrees on the flexion-extension radiographs.[Conclusion]There is a definite stabilization and motion after implant of cervical dics prosthesis.A functional discs prosthesis is an effective treatment of cervical disc herniation.There is a good early clinical result.The result of long follow up should be observed further

[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.