The early treatment principles of spinal cord injury (SCI) included early drug using, early surgery and early rehabilitation.The literatures on how to use drug early and how to control the time for SCI before surgery were reviewed.

Objective To conduct biomechanical study and three dimensional finite element analysis on lumbar spondylolysis and spondylolisthesis treated with single vertebra reduction and fixation system(LSRF), and to evaluate the long term outcome of isthmic spondylolisthesis treated with direct repair and fixation with LSRF. Methods Biomechanical characteristics of LSRF was tested, and three dimensional finite element model of lumbar spondylolysis and isthmic spondylolisthesis was established, the stress of lumbar in spondylolisthesis was observed after fixation and reduction. Thirty two patients with spondylolysis and isthmic spondylolisthesis were treated with direct repair and fixation with LSRF designed by the authors from 1992 to 1995. Eighteen cases had spondylolysis, and the others accompanied with spondylolisthesis. The patients age was 28-46 years, with an average of 36.4 years. Results The biomechanical study and three dimensional finite element analysis showed that LSRF has good ability in reduction and rigid fixation. All patients were followed up for an average of 5.6 years. The latest radiographs showed that bony union occurred in 29 cases. There was no breakage and pullout of screws except dislocation of hook in 2 patients. By Henderson standard, the result was excellent in 22, good in 6, fair in 2, poor in 2. Conclusion LSRF has stronger fixation strength and higher fusion rate. Direct repair and fixation with LSRF is a good procedure for younger and middle aged patients with spondylolysis and isthmic spondylolisthesis.

Objective To review and analyze the complications of spondylolisthesis treated wi th BAK interbody fusion cages.Methods One hundred and eighteen patients wi th spondylolisthesis were treated with BAK interbody fusion ca ges,the intraoperative and postoperative complications were reviewed,which include dural tear,nerve root injury,unsatisfactory cage position,cage retropulsion,cage subsidence and postlaminectomy adhesive arachnoiditis.Results The intraoperative complication ra te was 11%and the most commonly seen were dural tear 4c ases(3.4%),nerve root damage 3cases(2.5%)and unsatisfactory cage position 9cases(7.6%),2cases had both dural tear and unsatisfactory cage position,1patient had both nerve root injury and unsatisfactory cage position.The postoperative c omplication rate was 7.6%,which chiefly consisted of cage retropuls ion 3cases(2.5%),cage subsidence 4cases(3.4%),and postlaminec-tomy adhesive arachnoiditis 2cases(1.7%),2cases of cage retropulsion and 2ca ses of cage subsidence show partial nonunion,2cases of cage subsidence had arachnoiditis.Conclusion As a new technique,lumbar interbody fusion with BAK cages are r apidly gaining popularity,however,the complications described here suggest the importance of selection s of surgical indications and proper manipulations.[

Objective To evaluate biomeehanic characteristics of lumbar spondylolysis and spondylolisthesis single vertebrae reduction fixation system (LSRF), and discuss its mechanism of reduction. Method Twenty-four adult isthmus lumbar vertebrae specimen were disconnected and fixed with LSRF, Hefti, Salib's method respectively, and the biomechanic characteristics of the fixation devices were tested. Isthmus of L5 in 4 adult spine specimen was destroyed under loading to produce the spondylolisthesis model, and reduction by LSRF. Result The LSRF has a good ability for reduction and its strength for reduction is 1.6, 2.7 times as high compared with the Hefti, Salib's methods respectively. The mechanism of reduction is that the LSRF used contacted point of lamina by lamina hook as the fulcrum, through the pedicle screw to pull the spondylolisthetic vertebrae, and reduce the anterior displacement of vertebrae. Conclusion LSRF gives rigid fixation and good reduction, and provides a new and effective method for lumbar spondylolysis and isthmic spondylolisthesis.

Objective To analyze the long term results of thoracolumbar burst fractures treated with short segment pedicle instrumentation. Methods Sixty eight cases of thoracolumbar burst fractures fixed with short segment pedicle instrumentation were followed up for at least 5 years (5-13 years, average 8 years). All of them were checked with radiography pre and post operation and before implant removal. At final follow up assessment, all were examined with radiography, 18 cases were checked with CT scan as well. Results 1) Neurological status improved at least 1 Frankel grade in 90.3% of the patients who had preoperative incomplete paraplegia, while no improvement was obtained in those who had preoperative complete paraplegia. Low back pain was evaluated according to Denis Pain Scale, the results showed P1 41 cases (60.3%), P2 24 cases (35.3%), P3 3 cases (4.4%). 2) The shortest distances between the upper and lower pedicle screws tips shortened for 0-6.5 mm (average 2.5 mm) before removal in contrast to that at post operative immediately. Of the 68 cases, nuts loosened in 1 case, pedicle screws loosened in 1 case, bent in 2 cases and broken in 5 cases. Of the 8 cases whose implants were not removed timely, screw broke in 2 cases, and seepage occurred through incision in 2 cases. 3) At final follow up, the correction of anterior vertebral body height averaged 30.5%, and Cobb angle 5.8?, despite a mean correction loss of Cobb angle 12.1?. Correction loss was most evident at the above disc spaces, then the below disc spaces. Correction loss of vertebral body height averaged 1.9% in the anterior, and 6.0% in the middle part. 4) The collapse of vertebral body was most serious in the middle part. The deformity of "codfish vertebrae" occurred in the superior part of vertebrae body in 21 cases, among them the upper adjacent vertebral body sank into the injured body in 5 cases, 3 of whom engendered kyphoses greater than 25?. Evident intra corporeal gaps were found in 16 of 18 patients who were checked with CT, and the gaps communicated with the above disc space. The fractured body could have a deformity of the "cup" after reduction. 5) Degeneration and narrowing of the disc spaces next to fractured vertebrae were very common, and the above space disappeared in 27 cases, while the lower space disappeared in 14 cases. The upper disc space adjacent to fixation levels degenerated in 1 of 8 cases whose implants were not removed timely. Five patients had Cobb angle greater than 20?, three of them had low back pain, and one had mild symptom of nerve compromise. Low back pain was not correlated with degeneration of discs. Conclusion Short segment pedicle instrumentation provides satisfying stability for thoracolumbar burst fractures. It helps physiologic postural contour restoration and facilitates neural recovery, but is associated with relatively high rates of implant failure and correction loss which is most evident at adjacent discs spaces. Deficiency of bone grafting and delayed implant removal are the most probable causes for correction loss.

Objective To evaluate the efficacy and safety of balloon kyphoplasty in the treatment of painful osteoporotic vertebral compressive fractures. Methods From May 2000 to June 2002, 56 consecutive procedures were performed in 30 patients of painful osteoporotic vertebral compressive fractures with intact posterior vertebral body wall. Each procedure includes bilateral insertion of inflatable balloon, fracture reduction and fulfilled with bone cement. Preoperative and postoperative symptom levels, complications and radiographic findings were recorded and analyzed. Results All 30 patients tolerated the procedure well with immediate relief of their back pain in 48 hours. The mean loss of the anterior and mid vertebral body heights were (13.6?2.3) mm, (9.2?1.4) mm preoperatively and (4.7?1.5) mm, (3.4?1.1) mm postoperatively. The mean kyphosis was improved from 23.4??5.2? to 9.2??4.7?. Cement leakage and cerebrospinal fluid leakage occurred at one level respectively and resulted in no clinical symptoms, no other complication was found. Conclusion As a promising minimally invasive surgery, balloon kyphoplasty can provide early improvement of pain and function as well as spinal alignment in treatment of painful osteoporotic compressive fractures.

Objective To investigate the clinical results of bilateral transpedicular kyphoplasty for the osteoporotic vertebral compression fractures with single balloon. Methods From March 2002 to February 2004, percutaneous bilateral transpedicular kyphoplasty with single balloon was performed in 15 patients, who presented with painful vertebral compression fractures. In the group, there were 6 vertebrae of 6 males and 11 vertebrae of 9 females, and the average age of the patients was 70.5 years with a range of 62 to 82 years. 17 osteoporotic vertebral compression fractures, which involved 8 T12, 7 L1, 1 T8 and 1 T11, were treated. Osteoporosis was identified in all cases by the measurement of lumbar bone mineral density (BMD) and the evaluation of radiographs. The average BMD was 0.603 g/cm2. CT scan showed the posterior vertebral wall intact in all patients, and MRI displayed low signal on T1WI and high signal on T2WI of the vertebral fractures. Results All patients experienced dramatic pain relief after the procedures. The mean pain score (VAS) decreased significantly from 8.3 preoperatively to 2.1 after operation. The mean vertebral body height restoration was 54.2%?34.1% on the anterior border, 60.5%?35.4% in the middle portion, and 40.7%?32.3% on the posterior border respectively. And the sagittal alignment was improved significantly, as the average correction of the Cobb's angle reached 9.5?. No cement leakage was found on X-ray, except one with less cement at the anterior vertebral edge, but no clinical symptom occurred. All the patients were available at the final follow-up, the mean period was 10.5 months (range, 2-48 months). Conclusion Bilateral transpedicular kyphoplasty with single balloon not only can provide effective pain relief and vertebral height restoration, but also can improve the sagittal alignment significantly. Its clinical outcome was satisfactory.

0.05). Conclusion The study of the characteristic of track of percutaneous transpedicular puncture is good for the safe procdure under image guidance. The standard track is safe for transpedicular or parapedicular puncture. The percutaneous transpedicular puncturing sites can be located according to the spinous process.

Objective To investigate the effect of metformin on the osteogenic differentiation of human mesenchymal stem cells exposed to PMMA particles. Methods Human placental mesenchymal stem cells were iso-lated and cultured in vitro. The effect of metformin with different concentrations on cell viability was determined by CCK8 assay. The effect of metformin on the mRNA expression of osteogenic genes was detected by using real-time RT-PCR. Calcified nodules were stained by alizarin S. The effect of metformin on the expression of eNOS was also detected by using real-time RT-PCR. Results PMMA particles could inhibit the viability of mesenchymal stem cells. Metformin(0.05 mmol/L)could promote the viability of mesenchymal stem cells exposed to PMMA particles. Metformin(0.05 mmol/L)could increase the expression of osteogenic genes,including OCN,RNUX2,and ALP, in human mesenchymal stem cells exposed to PMMA particles. The calcium deposit was also increased after metfor-min treatment. Results of real-time RT-PCR showed that metformin could increase the expression of eNOS in human mesenchymal stem cells exposed to PMMA particles. Conclusions Metformin can increase the osteogenic differentiation of human mesenchymal stem cells exposed to PMMA particles,partially by inducing eNOS expression.

Objective To study the method of isolating and culturing stem cells from rat adipose tissue and to determine if adipose-derived stem cells(ADSCs)harvest from rat could differentiate into osteogenic and chondrogenic in vitro.Methods ADSCs were isolated from rat inguinal fat pads after extensive washing with phosphate-derived saline and digesting with collagenase.After primary culture in control medium and expanded to two passages,the cells were incubated in either an osteogenic medium or an chondrogenic medium for 2-4 weeks to induce osteogenesis and chondrogenesis,respectively.Evidences of Osteogenic differentiation,were detected by a ALP solution,and while chondrogenic differentiation was confirmed using the histologic Alcian blue staining at acidic pH.Expressions of osteocyte and chondrocyte specific genes were confirmed by RT-PCR.Results ADSCs can be isolated from rat adipose tissue and,expanded rapidly.It exhibited a heterogeneous population of fibroblast like cells morphologically.ADSCs induced to osteogenesis were stained positively for alkaline phosphatase activity after 2 weeks and formed mineralized nodular structures,as conformed by Von kossa staining.Expression of osteocyte specific genes,such as ALP,osteopontin,osteocalcin,was detected.ALP and osteopontin,were expressed constitutively in osteogenic medium after 2 and 4 weeks of culture.Expression of osteocalcin,was induced by osteogenic growth factors at 4 weeks.Induced to chondrogenesis cells were positive of Alcian blue staining under acidic conditions and expression of aggrecan and typeⅡ/Ⅹ collagen genes.Aggrecan and typeⅡcollagen genes were abundant after 2 weeks in chondrogenic medium.TypeⅩ collagen gene was detected at 4 weeks.Conclusion Adipose-derived stem cells can be isolated from rat adipose tissue.Their biological characteristics are similar with mesenchymal stem cells(MSCs),and have the potential to differentiate into osteogenic and chondrogenic lineage.It may be an idea source of ADSCs for tissue engineering.