Lumbar degenerative disease is one of the most common diseases in orthopaedic clinics, and the chronic low back pain caused by it seriously affects patients' living quality. Currently, intervertebral fusion and rigid fixation are the main surgical methods for lumbar degenerative disease. Although the intervertebral fusion and rigid fixation can achieve a higher fusion rate, due to the stress concentration of adjacent segments, the adjacent segment degeneration may occur and make the patient's satisfaction rate much lower than the imaging fusion rate. Dynamic fixation is a new fixing concept, which can control the abnormal motion of the spine segment while retaining part of the movement of the fixed segment. Moreover, dynamic fixation is also beneficial to reduce the degeneration of adjacent segments and the incidence of breakage of internal fixation. Nowadays, various lumbar transpedicular dynamic fixation systems have appeared on the market. Most of these transpedicular dynamic fixation systems are derived from the design of pedicle screws and rods used in spinal fusion surgery in the 1980 s and 1990 s. The original intention of their design is to stabilize the abnormal segments and reduce the pressure on degenerated intervertebral discs and facet joints, while maintaining the normal movement of relevant segments. By reviewing the biomechanical research, clinical efficacy, existing problems and advantages and disadvantages of common backward lumbar transpedicular dynamic fixation systems, this article intends to provide new ideas for the improvement of the backward lumbar transpedicular dynamic fixation system design, as well as offering surgical treatment strategies for clinicians.

Objective To analyze the clinical efficacy and relative influence factors of self-expanding metallic stents (SEMS) in treating colorectal cancer obstruction.Methods Information of 47 patients received SEMS to treat colorectal cancer obstruction from Mar.2012 to Dec.2017 in Beijing Haidian Hospital were collected,who were then followed up in outpatient or by telephone.Effective rate,survival rate and complications were recorded and calculated by the software of SPSS 17.0.Chi-square test was used to analyze relative influence factors.Results Results shown that the clinical efficacy was 100％ (47/47).Patients' 30-day survival rate and 6-month survival rate were 87.2％ (41/47) and 68.1％ (32/47),respectively.After surgery,2 patients presented with perforation,3 patients presented with migration and 5 patients presented with reobstruction.Clinical stage of tumor and stent length were related with complications and survival.Therein,complications presented more in patients with advanced cancer.And the longer stent length,the higher mortality.Conclusions Clinical stage of tumor and stent length maybe risk factors of complications and survival of patients after SEMS surgery of colorectal cancer obstruction.

Mesenchymal stem cells(MSCs)were derived from the early development stage of mesoderm and ectoderm and considered as one of the important members of stem cells family. Besides that, MSCs can be isolated easily and don′t have a limitation of moral and ethical problems. Moreover, MSCs can be expanded in vitro which make it possible to use in industrial preparation. Moreover, MSCs possess low immunogenicity and has the ability to home to damaged tissues, tumors, and metastases. Therefore, MSCs possess a set of fairly unique properties which make them ideally suited for clinical applications. This review summarizes the main properties of MSCs and its new progress in drug delivery system in the field of cancer therapy as a basis of further utility of engineered MSCs in the design of targeting drug delivery system.

ObjectiveTo explore the clinical outcome of one stage posteroanterior decompression and bone implant in the treatment of severe lower cervical spinal bony canal stenosis. Methods The study involved 29 patients with severe lower cervical spinal bony canal stenosis treated with one stage posteroanterior decompression and bone implant from April 2006 to March 2009. There were 11 patients with old fractures, seven with posterior longitudinal ligament ossification and 11 with cervical disc calcification. The course of disease ranged from 2 months to 3.2 years, average 1.4 years. The nerve function was rated as grade B in two patients, grade C in 19 and grade D in eight according to Frankel scale. The average Japanese Orthopaedic Association (JOA) score was 9.8. ResultsAll patients were followed up for 7-28 months (average 15.2 months), which showed bony fusion five months after operation, with fusion rate of 100％. The Frankel grade was increased for average 1.2 grades and the nervous symptoms alleviated remarkably. Mean postoperative JOA score was 13.8 and increased for mean 4.0, with mean amehoration rate of 55.6％. ConclusionsOne stage posteroanterior decompression and bone implant is a safe and effective method for treatment of lower cervical spinal bony canal stenosis, when the intraoperative electrophysiological monitoring can assure the operative safety.

BACKGROUND:Studies have demonstrated that tetrandrine has protection on acute spinal cord injury,but the specific mechanism remains poorly understood.OBJECTIVE:To study the protection of tetrandrine on rat acute spinal cord injury and to study its mechanism from apoptosis pathway.METHODS:A total of 100 rats were randomly divided into 4 groups.All rats were prepared for spinal cord injury models using modified Allen method except that in the sham-surgery group.Methylprednisolone and tetrandrine was injected into rats in the methylprednisolone and tetrandrine groups by tail intravenous injection prior to and at 24,48 hours after model preparation.The same volume of physiological saline was injected in the sham-surgery and model groups.Basso-BeatUe-Bresnahan(BBB score)was recorded at 8 hours,1,3,7 and 14 days after model preparation.The morphological changes of spinal cord injury sites were observed by hematoxylin-eosin staining and the expressions of bcl-2 and bax were determined by immunohistochemistry.RESULTS AND CONCLUSION:The BBB score of methylpradnisolone and tetrandrine groups were significantly higher than that model group at 7 and 14 days(P<0.05),but there were no significant difference between the methylprednisolone group and tetrandrine group(P>0.05).Hematoxylin-eosin staining showed that the spinal cord injured severely at 3-7 days,the injury degree in the methylpradnisolone group and tetrandrine group was slighter than that of the model group,with smaller bax expression and greater bcl-2 expression(P<0.01).The findings demonstrated that,tetrandrine is able to protect neurons from apoptosis and promote the nerve function recovery by inhibiting the expression of Bax and promoting the expression of Bcl-2.Its effect is not inferior to methylprednisolone.

BACKGROUND: For its extensive sources and specific biological characteristics, heterogeneous deproteinized bone (DPB) as the tissue-engineered scaffold material gets a good application prospect in repair of large segmental bone defects.OBJECTIVE: To prepare scaffold material by compositing modified heterogeneous DPB with recombinant human bone morphogenetic protein 2 (rhBMP2) and evaluate the osteogenic ability in repairing large segmental long bone defects in large-sized animals.METHODS: Twenty-four goats were randomly and evenly divided into three groups: DPB, autologous bone, and DPB+rhBMP2. Bone defects (20% in length) were made in the middle and lower segments of the right tibia of each goat, and according to group design,different bone grafts were implanted and fixed using semi-ring slot external fixer. At 4-24 weeks after surgery, X-ray examination was performed once every other 4 weeks. At 24 weeks after surgery, newly formed bones were taken out for determining the repair effects of bone defects through duat-energy X-ray analysis, histological observation, and biomechanical analysis.RESULTS AND CONCLUSION: The prepared DPB exhibited a three-dimensional porous structure, with a porosity of (78.5±6.45)% and pore size of (472.5±7.02) μm. Time-dependent bone repair was found in each group. Results regarding anti-compression test, three-point anti-bend test, and anti-torsion test were greatest in the autologous bone group, followed by the DPB+rhBMP2 group, and lastly the DPB group. There were no significant differences in tibial bone density, bone mineral content,anti-compression pressure and ultimate pressure, anti-bending load and ultimate toad, anti-torsion torque and ultimate torque between autologous bone group, DPB+rhBMP2 group and normal bone control group. These findings indicate that modified heterogeneous DPB composited with rhBMP2 has osteogenic ability equivalent to autologous bone in repairing large segmental long bone defects in goat tibias. Therefore, it can be applied as tissue-engineered scaffold material.

BACKGROUND: There are few reports about vascularization in the repairing of bone defect by heterogeneous deproteinized bone.OBJECTIVE: To verify the vascularization characteristics of heterogeneous deproteinized bone, tissue engineering scaffold material, in the repairing of large segmental bone defect.DESIGN, TIME AND SETTING: The randomized controlled animal experiment was performed between March 2005 and February 2007 at the Third Military Medical University, Chongqing, China.MATERIALS: Twenty-four 10 to 12 months old goats, weighing (22.5±2.5)kg, were obtained from the Animal Center of the Third Military Medical University, Chongqing, China. Segmental bone defects of 20 percent right tibia middle and inferior diaphysis of the 24 goats were made.METHODS: The 24 goats were divided into test group (n=16) and control group (n=8) randomly. Goats in test group were implanted with deproteinized bone+autologous MSCs+recombinant human bone morphogenetic protein-2 (rhBMP-2), goats in control group were implanted with autograft bone, and all fixed with half-ring sulcated external fixator. Every 4 weeks, 3 goats were killed after ink perfusing through femoral artery. A thick slice of new bone tissue was made to observe the vascularization.MAIN OUTCOME MEASURES: Vascularization of new bone observed through gross anatomy and imaging; vascular network of new bone observed through thick section, blood vessel amount and area measured by Image-proplus really image analysis software.RESULTS: No goat was infected or dead. Animal soft tissue was dyed black, blood vessels'size, ditribution and network structure were observed in subcutaneous tissue, fascia and periosteum. At 4 weeks postoperation implant margin became crude in the defect area; at 8 weeks postoperation transparent bone absorbing area of different size and irregular shape appeared; after 12 weeks postoperation high-dense calcification shadow appeared at the ends of defect bone and new bone connected with the ends completely. On 4 to 24 weeks postoperation, the blood vessel amount became large, alignment became regular, and their size and distribution became uniform. It showed no significant difference in blood vessel amount and area between 2 groups (P>0.05).CONCLUSION: Composite of heterogeneous deproteinized bone+autologous MSCs+rhBMP-2 has the same vascularization degree. of autogeneous bone graft in repairing of large segmental tibia defect.

BACKGROUND:Half-ring sulcated external fixator is a bone external fixation device.Its structure is relatively simple,with multi-plane fixed,and small occupying space.So far,there are few experimental reports about construction of tibial defect model by it in large animals.OBJECTIVE:To validate the practicality and repeatability of half-ring sulcated external fixator in establishing tibial defect models in goats.DESIGN,TIME AND SETTING:The randomized controlled observation was performed at the Animal Laboratory of the Third Military Medical University from March 2005 to February 2007.MATERIALS:Nine healthy adult(Animal Center of Third Military Medical University);Half-ring sulcated external fixator,made by Professor Li of the Third Military Medical University;Osseous pin,ψ2.5 mm,Shanghai Medicai Instruments Co.,Ltd.METHODS:After animals were anesthetized,two needles were threaded in the same plane of cancellous bone about 1.5-2.0 cm above the superior articular surface of the tibia,named group 1.The angle between the two needles was 40°.One needle was threaded at the place of 3.0 to 5.0 cm under the group 1 and parallel with optional needle of the group 1,named group 2.Needles of group 4 were threaded at the cancellous bone that was 2.0 cm from the joint surface of inferior extremity of the tibia.One needle was threaded at the place of 3.0 to 5.0 cm from group 4 and parallel with optional needle of the group 4.The included angle between these two needles of group 2 and group 3 was 60°.There were totally 6 needles.Tibia was fixed by half-ring sulcated external fixator.According to the length of the tibia from X-ray,tibia and periosteum were amputated by wire saw between the two needles in the middle and inferior segment of the tibia to make segmental bone and periosteal defects of 20 percent of tibia.MAIN OUTCOME MEASURES:①Postoperative general state of the animals and effect of half-ring sulcated external fixator.②Self-repair of bone defects by X-ray and Lane-Sandhu scoring standards.RESULTS:Of the 9 selected goats,1 died of postoperative infection,and 1 developed pinhole infection and supplemented.All the others survived and were included in final analysis.The goats were awake within 2-6 hours after surgery and able to stand up to eat.The loosening nuts were screwed up.No external fixation failure or loosening was found.No skin was necrotic.Injured limb could touch the ground in 2 days,but could not bear load until 2 weeks.The goats could walk in three weeks with a slight limp,then moved freely without claudication in four weeks after the operation.At the 5th week after operation,the radiographs showed little periosteal reaction.At the 10th week after operation,sclerosis was found in the fracture ends,and medullary cavity started to close.Fifteen weeks after operation,the medullary cavity closed and periosteal reaction did not aggravate.Inaddition.Lane score was 0 at any time point.No bone formation was found in the histological examination at 5,10 and 15 weeks after operation,and Lane score was 0 at any time point.CONCLUSION:The goat model established in goat tibia with 20%defects by the half-ring sulcated external fixator shows no bone healing after 15 weeks by X-ray or histological exanimation,indicating this is a practical and repetitive method to establish animal models of large segmental defect for bone tissue engineering.