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Objective To evaluate the accuracy and reliability of O-arm-based thoracolumbar pedicle screw installation.Methods A retrospective review was conducted on 75 patients who had undergone thoracolumbar pedicle screw fixation assisted with O-arm navigation (navigation group,n =32) and C-arm fluoroscopy (fluoroscopy group,n =43) from March to October 2014.All the patients were assessed with X-ray and CT images after operation.Accuracy of screw installation in both groups was compared.In navigation group,screw directions were measured on the sagittal and axial images of intraoperative navigation and post-operative CT scanning to evaluate the concordance.Results In fluoroscopy group,a total of 206 pedicle screws were placed with the one-time success rate of 93.2％ and accuracy of 90.8％ for screw placement,and one misplaced screw (grade llⅢ) led to L3 nerve root symptom.In navigation group,a total of 226 pedicle screws were placed with the one-time success rate of 100％ and accuracy of 96.9％ for screw placement,and no screw was grade Ⅲ.Further,there were no significant differences in screw directions on the sagittal and axial images between intraoperative navigation and postoperative CT scanning (P ＞ 0.05).Conclusion O-arm navigation that provides high-resolution images and high precision improves the accuracy of thoracolumbar pedicle screw installation,and possesses good reliability.
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Objective To construct genipin-crosslinked rat acellular spinal cord scaffolds and evaluate their enzymatic degradation rate,biomechanical properties and cytotoxicity.Methods Rat spinal cord scaffolds were decellularized by chemical extraction and chemically crosslinked with 5 g/L genipin solution.Micro-structure of the uncrosslinked and genipin-crosslinked acellular spinal cord scaffolds were observed by HE staining and scanning electron microscopy and properties of pore size,porosity,water ratio,and degradation rate in 2.5 g/L trypsin enzyme solution were examined.Ultimate tensile strength and elastic modulus of normal rat thoracic spinal cord,uncrosslinked and genipin-crosslinked acellular spinal cord scaffolds were determined on Instron mechanical testing instrument.Rat bone marrow mesenchymal stem cells were cultured in lixivium of uncrosslinked and genipin-crosslinked acellular spinal cord scaffolds and MTT assay for relative cell growth rate was test to evaluate the cytotoxicity of scaffolds.Results The uncrosslinked and the genipin-crosslinked acellular spinal cord scaffolds possessed a similar three-dimensional mesh-porous structure with a mean pore diameter about 30 μm and a porosity over 80％,but there was a statistical difference between the two groups(P ＞ 0.05).Water ratio of genipincrosslinked scaffolds was (229.7 ± 12.5) ％,far lower than (283.4 ± 11.2) ％ of uncrosslinked scaffolds (P ＜ O.05) ; genipin-crosslinked acellular spinal cord scaffolds had lower weight loss at each time point than the uncrosslinked acellular spinal cord scaffolds (P ＜ 0.05),but the stability in trypsin,ultimate tensile strength and elastic modulus of acellular spinal cord scaffolds were significantly enhanced by genipin-crosslinking (P ＜ 0.05).Furthermore,no obvious cytotoxicity was observed in the uncroslinked and genipin-crosslinked scaffolds.Conclusions Rat acellular spinal cord scaffolds present no obvious change in structure after genipin-crosslinking,but there is significant improvement in the biomechanical properties and ability against enzymatic degradation and no marked cytotoxicity.Hence,the genipincrosslinked scaffolds are promising in tissue engineering for spinal injury.
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Objective To observe three-dimensional structure and biological features of rat acellular spinal cord scaffold prepared by sonic oscillation and chemical extraction in order to offer an ideal scaffold for spinal cord tissue engineering research.Methods Rat spinal cord underwent acellular treatment with sonic oscillation and chemical extraction (Triton X-100 at volume fracture of 2％ and sodium deoxycholate at volume fracture of 2％) (acellular spinal cord group).In contrast with spinal cord tissue of normal rats (control group),general morphology,histology and ultramicro three-dimensional structure of acellular spinal cord scaffold were observed and aperture size,factor of porosity,water ratio,enzymolysis ratio and stability in water solution of the scaffold were also detected.Results Acellular spinal cord group showed effective removal of original cell components with factor of porosity for (94.57 ±3.45) ％ and water content for (88.62 ± 1.0) ％,and satisfactory three-dimensional structure with average aperture of 46 μm.Scaffold showed gradual degradation in enzymolysis solution and enzymolysis rate reached (69.03 ± 2.19)％ at 20 hours.Besides,scaffold showed stepwise disintegration in double distilled water and hydrolysis rate was (62.55 ± 1.70) ％ at 8 days.While,normal spinal cord showed close structure,generous neurons and myelin sheath with factor of porosity for (0.04 ± 0.02) ％ and water content for (62.4 ± 1.5) ％,and unobvious pore structure under scanning electron microscope.Normal spinal cord were degraded gradually in enzymolysis solution and enzymolysis rate was (37.62 ± 0.9)％ at 20hours.In the meantime,normal spinal cord were disintegrated gradually in double distilled water and hydrolysis rate was (40.97 ± 0.81) ％ at 8 days.Conclusions Acellular spinal cord scaffold prepared by sonic oscillation plus chemical extraction achieves complete removal of cell components,intact extracellular matrix,and satisfactory results in three-dimensional network structures,factor of porosity and water content.Also,the scaffold meets theoretical demands of tissue-engineered spinal cord scaffold and is an ideal alterative for tissue-engineered spinal cord scaffold.
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ObjectiveTo retrospectively analyze the treatment of odontoid fractures using percutaneous and open anterior screw fixation,and compare the clinical and radiographic results of the two techniques.MethodsFrom March 2003 to May 2010,115 patients with odontoid fracture were treated with anterior screw fixation,and all patients were followed up.The mean age of the patients was 43.5 years (range,16-71).Forty-seven patients who underwent percutaneous anterior screw fixation were set as the percutaneous fixation group,including 42 cases of type Ⅱ odontoid fracture and 5 of rostral type Ⅲ fracture.Sixtyeight patients who received open anterior screw fixation were set as the open fixation group,composing of 61cases of type Ⅱ odontoid fracture and 7 of rostral type Ⅲ fracture.We compared the operative time,intraoperative blood loss,X-ray exposure time,fracture union and complications between the two groups.Results The average follow-up duration was 37.6 months with a range of 12-70 months.The gender,age,classification of odontoid fractures,time after the injuries and concomitant spinal injuries showed a similar pattern in both groups.The operating time and intra-operative blood loss in percutaneous fixation group were (40.3±9.5)min and (5.6±4.1) ml respectively,and in open fixation group were (62.9±15.3) min and (47.1±28.6) ml respectively,both of them were significantly superior in percutaneous fixation group than in open fixation group (P＜0.05).There was no statistical difference in radiation exposure time,fracture union and incidence of complication between the two groups.ConclusionComparing with open screw fixation,percutaneous anterior screw fixation is a safe and reliable procedure for treatment of type Ⅱ and rostral type Ⅲ odontoid fractures with potential advantages.
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Objective To evaluate the clinical outcome of artificial cervical disc replacement and cage fusion in the treatment of multi-segmental cervical disc herniation. Methods A total of 39 patients with multi-level cervical disc herniation were treated with disc replacement and adjacent segment cage fusion at one stage. There were 29 patients with two level cervical disc herniation, nine with three level cervical disc herniation and one with four level cervical disc herniation. Of the patients, there were 17 male and 22 female, aged between 35 and 63 years ( mean age 47 years). The herniated disc was located at C3-4 and C4-5 in two patients, C4-5 and C5-6 in 15, C5-6 and C6-7 in nine, C4-5 and C6-7 in three, C3-4,C4-5 and C5-6 in four, C4-5, C5-6 and C6-7 in five and C3-4, C4-8 , C5-6 and C6-7 in one. There were 18 patients with myelopathy and 21 with radieulopathy. The stabilization and the range of motion of implanted disc,the fusion of cage and the displacement of cage were observed on dynamic radiograph postoperatively. The clinical symptom and the neurological function were evaluated according to JOA score and odom' s criteria. Postoperative clinical symptoms and daily function were evaluated by using neck disability index (NDI) scale. Results Twenty-nine patients with bi-level cervical disc herniation underwent single level disc replacement and cage fusion on adjacent segment. Nine patients with three level disc herniation underwent single level disc replacement in seven and level cage fusion on adjacent segment in two. Twopatients underwent two level disc replacement and one level cage fusion. One patient with four level disc herniation was treated with two level disc replacement and two level cage fusion. The patients were followed up for from 6 moths to 3 years, which showed that definite stabilization was achieved for all disc with average range of motion for 9.3 degrees postoperatively. Solid fusion was achieved in all cage, with no subsidence or displacement of cage. The JOA score was increased from 9.1 to 13.2 at final follow up and the NDI (neck disability index) score decreased from 41.8 reduced to 29.5 at final follow up. The clinical success rate (excellent/good/fair) according to Odom' s Criteria was 85%. Conclusion Cervical disc replacement and cage fusion can attain definite stabilization and satisfactory mobility and provide a new effective treatment for cervical disc herniation. The long-term outcome needs further clinical followup.
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Objective To explore the fixation method of tibial helical plate for treatment of proximal and middle one-third of humeral fractures and evaluate the clinical outcome. Methods A review was performed on 15 patients with proximal and middle one-third of humeral fractures treated by tibial helical plate from May 2004 to February 2009. There were 10 males and five females, at age range of 19-65 years ( average 38.0 years). The surgical method was summarized and the shoulder function evaluated.Results The follow-up lasted for 7-24 months (mean 13 months) , which showed bony union in all patients, with mean union time of 4.7 months. There was no implant loosening or failure. According to Neer 's criteria, the result was excellent in seven patients and good in six, with excellence rate of 86.7%.Conclusions Open reduction and internal fixation using tibial helical plate is simple and effective for treatment of proximal and middle one-third of humeral fractures.
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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.
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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.
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Objective To explore feasibility and therapeutic effect of posterior decompression by vertebral body resection, interbody bone fusion and transpedicular screw internal fixation in treatment of severe rotational throracolumar fracture and dislocation. Methods From October 2007 to July 2008, nine patients with severe rotational throracolumar fracture and dislocation classified as AO C types under-went decompression by vertebral boby resection, intervertebral bone fusion and transpedicular screw inter-nal fixation via a posterior midline small incision. There were eight males and one female, at age range from 23 to 54 years. All patients involved levels at T_(11)-L_2. According to AO classification, there were three patients with type C1 bursting fractures with rotational dislocation, five with distraction fracture com-bined with rotational dislocation and one with rotational distraction shear fracture/dislocation. The preop-erative Frankel Grading was Grade A in three patients, Grade B in one, Grade C in four and Grade D in one. Postoperative neurological status, the correction and loss of dislocation and the location and union of bone graft were reviewed. Results All patients received successful operation, with operation time of 3.5-5.8 hours (mean 4.4 hours), blood loss of 1 200-3 500 ml (mean 1 800 ml). The follow- up period in nine patients was 3-12 months (mean seven months). Postoperative X-ray photographs showed that the dislocation in all patients was reduced, the spine curvature was recovered to normal and the intervertebral bone graft was well fixed. Three patients at Frankel Grade A had no improvement, one at Grade B was improved to Grade C. Of four patients at Grade C, three patients were improved to Grade D. The follow-up showed bony fusion in all patients, with no loosening, dislocation or breakage of the internal fixation or implants. Conclusions For severe rotational throracolumar fracture and dislocation, decompression, reduction, fusion and fixation are rather difficult, while sufficient posterior decompression by vertebral body resection, rigid interbody bone fusion and transpadicular screw internal fixation can be an effective alternative measure.
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Objective To study the indications and clinical outcome of the upper cervical spine via the high anterior cervical retropharyngeal approach in treatment of upper cervical spine injuries. Methods There were 41 patients including 32 males and 9 females, at age of 12-67 years. Of all patients, there were 21 patients with Hangman fractures, two with fracture of C2 vertebral body, 12 with irreducible atlantoaxial dislocation secondary to os odontoideum, four with C1,2 tuberculosis and two with C2 gaint cell tumor. All patients underwent the high anterior cervical retropharyngeal approach to expose C1C3. C2,3 fusion followed by self-locking plate was performed for Hangman fractures and C2 fractures. Ventral reduction plud posterior aflantoaxial fusion was done for irreducible atlantoaxial dislocation secondary to os odontoideum. Lesion was cleared for tuberculosis and the tumor was resected and reconstructed. The neurological funcation was evaluated according to the ASIA criteria, the JOA score and Odom' s criteria. Results Successful exposure of arch of atlas to C3 was achived in all 41 patients, with satisfactory reducation, decompression, fusion, lesion resection and reconstruction. The trauma patients with normal neurological function showed no neurological deficit postoperatively, but those with quadriparesis had partial recovery. While the patients with illness obtained marked recovery of neurological function, with the JOA score from preoperative 8.9 to 12.5 at final follow-up. The clinical success rate (excellent/good/fair) reached 94. % according to Odom' s Criteria. Hypoglossal symptom was found in three patients and facial nerve symptom in two, without wound infection. Conclusions Via the high anterior cervical retropharyngeal approach, the upper cervical spine can be thoroughly exposed to facilitate reduction, decompression and reconstruction and maximally restore physiological function of the cervical spine in treatment of the upper cervical spine injuries.
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0.05).Measurement results of adjacent segment movement extention showed more significant changes in the fusion group than in the non-fusion group(P
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[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.
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[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.
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[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.
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[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.
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[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
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[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
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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.
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Objective To prepare the acellular scaffold of spinal cord and analyze its component.Methods The acellular scaffold was prepared with the freeze thawing and chemical extraction,its structure was observed by HE and SEM,its component was analyzed by immunohistochemistry.Results The cells,myelin sheath and axon of nerve fibers in the rat spinal cord were eliminated,but three-dimensional supports of extracellular matrix were reserved.The analytical results showed the component of the acellular spinal cord contain laminin,fibronectin and type Ⅳ collagen—the necessary components to facilitate and induce the regeneration of the injured nerves and enhance the adhesion and proliferation of cells.Conclusion The acellular spinal cord has three dimensional structure and contains several proteins related to the regeneration of the injured nerves and promotion of the survival and proliferation of cells.
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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.