Objective To evaluate the biomechanical featu res of the HOIST in the treatment of lumbar spondylolisthesis.Methods Seven fresh cadaver specimens from L 2 to sacrum was used in the study.Each specimen was tested in five states:intact state as the control,spon dylolisthesis model by Panjabi meth od without fixation,spondylolisthesis model fixed with HOIST device,fatigued test of the HOIST and fixed with DICK system.During the experiment,the flexion,extension,bilateral bending and axial rotation loading we re applied to the specimens and measure d with three dimensional analysis ap paratus.A fatigue process of HOIST device was carried out with multifunctional test system(MTS 858,American).The ranges of motion(ROM)of spinal segments were determined with two special cameras and t test was used in statistical analysis.Results The ROM in spondylolisthesis state was significantly greater than that o f the others(P0.05).The difference among two HOIST grou ps and DICK group was not significant at the0.05level except the ROM of left axia l rotation(P

Objective To observe the expansion of transverse width of post screw-implantation in the pedicle and assess the effect of the relative diameter and BMD on the expansive rate. Methods There were 48 vertebral bodies, and 96 pedicles, obtained from 4 human cadaveric T2～L1 specimens (the mean age of 41 years). The BMD(A), pedicle width (B) and height were measured respectively. According to groups of BMD(A1:0.44～0.52 g/cm2;A2:0.52～0.70 g/cm2;A3:0.70～0.92 g/cm2 and the relative diameter(screw/pedicle)(B1:40%～55%;B2:55%～70%;B3:70%～85%), the tests were classified into 9 groups (A1B1?A1B2 ?A1B3?A2B1?A2B2?A2B3?A3B1?A3B2 and A3B3). The implantation procedure was carried out under the uniform standard. Results The number of valuable date was 85, while 11 dates were excluded, including 4 burst pedicles in A3B3 group. According to the statistical analysis, the pedicle width was expanded after implantation. The expansive rate of pedicle width was influenced significantly by the relative diameter and BMD(P

Objective To introduce the indications and surgical technique of pedicle subtraction osteotomy (PSO) for patients with rigid kyphotic scoliosis. Methods Fifty-eight consecutive patients (21 males, 37 females) with rigid kyphotic scoliosis were operated with PSO at the apical vertebra. The average age was 14.1 years (ranged from 4 to 27 years). Among them, 31 were congenital deformity while 26 with idiopathic scoliosis and 1 with neurofibromatosis scoliosis. 9 had previous surgery history. The average preoperative Cobb's angle of scoliosis and kyphosis was measured as 83.7? and 78.2? on standing films and as 71.1? and 76.3? on the distraction films. On the bending films, scoliosis and kyphosis were corrected by 12.4% and 23.8% respectively. The associated neurologic deficits were observed in 14 patients, bony or fibrous septum in the canal was found in 6 patients on the preoperative CT or MRI. All patients underwent pedicle subtraction osteotomy at the convex side of the apical vertebra with segmental pedicle screw fixation or Luque instrumentation. The level of osteotomy varied from T8 through L1. Results Most patients were improved in terms of pain and radiographic examinations. The average follow-up period were 26.7 months in 49 cases (ranged from 5 to 69 months). The average residual angle of scoliosis and kyphosis was 30.0? and 21.3? respectively. The average correction rate of scoliosis and kyphosis was 64.2% and 63.5% respectively. The complete neurologic recovery was obtained in 11 and partial recovery in 2 at three months postoperatively. One case showed no improvement 12 months after surgery. No patients developed severe complications while 2 had pneumonia(3.4%), 2 had superior mesenteric artery syndrome (3.4%) and 5 had temporary dysfunction of one or both lower extremity (8.6%). The loss of correction was 1.8% at one-year follow-up. Conclusion Pedicle subtraction osteotomy is a reliable technique for severe and rigid kyphotic scoliosis both in adolescents and adults, and for severe congenital deformities and revision surgery. With pedicle subtraction osteotomy at the apical vertebra and segmental pedicle screw fixation, the rigid deformities can be corrected in one-stage, neurovascular complications can be greatly reduced, both the spinal balance and stability can be restored. The patients is able to ambulate with a brace as early as three weeks after surgery.

objective To analyze the causes of early complications following posterior lumbar spinal operations and to find out about the way for prevention and treatment of those complications. Methods From 1998 to 2002, 903 patients underwent posterior lumbar spinal operations ,there were 587 males and 316 females , with an average age of 36.7years (range, 18 to 78 years ). The diagnosis of patients included lumbar disc prolapse in 483, lumbar stenosis in 145, lumbar spondylolisthesis in 96, lumbar fracture in 94, lumbar instability in 27, lumbar tuberculosis in 15 spinal tumors in 24 and reoperation in 19. All patients were evaluated by the medical history, clinical examination and review of the imaging data, and then the surgical plan was made respectively according to clinical evaluation. Results Early complications of 78 complications within 2 weeks post-operatively occurred in 76 cases with the incidence of 8.6%(78/903), in-cluding of 49 males and 27 females with an average age of 44.6 years. The complications consisted of 50 nerve root irritations(64.1%, 50/78), most of which relieved at 4 to 30 days after treatment, 9 gastrointesti-nal symptoms(11.5%, 9/78), all of which disappeared at 3 to 10 days but 2 cases needed enema, 4 hematomas of incisional wound(5.1%, 4/78), 4 cerebrospinal fluid leakages(5.1%, 4/78), 3 urinary reten-tions(3.9%, 3/78), 2 deep infections(2.6%, 2/78), 2 deep vein thrombosis(2.6%, 2/78), 2 pulmonary em-bolisms(2.6%, 2/78),1 infection of urinary tract(1.3%) and 1 fatty liquidization(1.3%, 1/78). The opera-tional procedure possible leading to surgical complication were laminectomy, nerve root dissection and in-strumentation. Conclusion Early complications may determine the clinical result of the posterior lumbar spinal operations. Besides the skilled technique, thorough pre-operative planning, close observation and proper management after operation, and early post-operative rehabilitations are of great benefit to the pre-vention and treatment of the complications.

Objective To determine the cause, prevention and management of failed spinal deformity surgery, and evaluate the indication of spinal revision. Methods Thirty-one cases of failed spinal deformity surgery were treated surgically. There were 18 males and 13 females with an average age of 14.7 years(ranged from 4 to 35 years) at the present procedures. The average number of previous surgeries for this group of patients was 1.5 times. The duration between the first surgery and revision was 13-114 months, with an average of 47.9 months. There were 16 patients with consistent back pain which became worse after movement, 5 patients with implant complication (broken, loosing, explosing), 21 patients with failure of instrumentation and deterioration of deformity, 5 patients with decreased sensory and motor function. The average preoperative angel of deformity was 75.3 degrees for scoliosis and 76 degrees for kyphosis and the flexibility was 9.8% and 25.2%, respectively. All patients underwent reconstructive surgery with segmental vertebral osteotomy and trans-pedicular fixation and fusion in one or two stages according to the location and degree of the deformity. Results The average follow-up period for this group of patients was 31.8 months in 20 cases. The postoperative correction rate for scoliosis and kyphosis was 55.2% and 67.5%, respectively. There were 4 cases (12.9%) developed temporary neural dysfunction postoperatively and were recovered within 1-3 weeks after appropriate treatment. Instrumentation failure was occurred in two cases and there was no other complication in this group. Conclusion It is might be benefit to follow the principle of spinal deformity correction, fuse with adequate bone grafting and combine with proper pedicle fixation, especially for the congenital scoliosis patients, which are the efficial methods to prevent the failure of spinal deformation surgery. The management for the patients suffered from long-time back pain, spinal pseudarthrosis or progressive aggravated deformity postoperatively should be individuated depending on the degree of deformity, flexibility of the spine and the age of patients.

[Objective]To evaluate the indications,efficacy and safety of posterior total laminectomy decompression and reduction with pedicle screws for lower cervical fracture and dislocation.[Method]From June 2005 to February 2008,41 patients with lower cervical fracture and dislocation received posterior total laminectomy decompression and reduction with pedicle screws.The patients(M=32,F=9)were 22-47 years old,with an average of 33.5 years old.There were 38 fresh and 3 old injuries.[Result]All the patients were operated on successfully without severe complications during perioperative period.Totally 252 (89%) screws were exactly implanted in the cervical pedicle.The everage surgery time was 3.1 h (2.5-4 h).The average blood loss during the operation was 460 ml (250-950 ml). The average time of follow-up was 27.5 months(24-36 months). All patients had satisfiactory reduction and no internal fixator failure.Thirty-two patients who were followed up for more than 24 months had complete fusion. The motor and sensory score (ASIA92) were improved significantly at 2 years follow-up(P

Purpose: Through the analysis of 202 cases of spondylolisthesis treated with surgery, the different types of surgical procedures were reevaluated. Material and Method: Patients with spondylolisthesis were divided into 3 groups based upon their pathology and different surgical procedures were used accordingly. The results were evaluated after follow-up of more than one year. Group Ⅰ consisted of 38 patients with degenerative spondylolisthesis with back pain and isthmic spondylolisthesis of less than 33%; they were treated with anterior intervertebral body fusion. Group Ⅱ consisted of 99 cases of mild isthmic spondylolisthesis with unilateral sciatica, and were treated with semi-laminectomy and decompression of symptomatic side; interlaminar and interspinous process fusion of the opposite side was performed for 99 cases of mild isthmic spondylolisthesis with unilateral sciatica. Group Ⅲ consisted of 65 cases of spondylolisthesis more than 33% with sciatica and they were treated with decompression, reduction of sliding vertebra and posterior intervertebral body fusion. Result: In group Ⅰ, solid fusion was in 20 cases giving a fusion rate of 91%. In group Ⅱ, the satisfactory rate was as high as 91.5%. In group Ⅲ, the satisfactory rate and fusion rate reached 91.8% and 95.9% respectively. Conclusion: Reduction of spondylolisthesis could increase the fusion contact area, restore normal mechanics and saggital curve of the lumbar spine, relieve neural compression and improve the extemal appearance and function. For the surgical treatment of spondylolisthesis, the major goal should toward a solid fusion between the sliding vertebra and its adjacent vertebrae and laminectomy alone is not a procedure of choice.

Objective To describe the structure and clinical application of the single arm suspended reduction fixation device(HOIST device) for spondylolisthesis. Methods HOIST device is composed of the hauling screw, open angle screw(upholding screw), blocker, angle connective bar and blocking ring. Through the different assembly of the angle screws and the connective bar, to increase or decrease the fixation angle of the angle screw which as an upholding arm and the connective bar to meet the needs of different lumbosacral angles and hauling screw reducing distance. Twenty three patients with an average slipping rate of 25％－ 50％ , were treated with the device, and among them, intervertebral implantation of BAK was done in 5 patients and intervertebral fusion was performed in 18 patients. Results The mean duration of follow up was 10.3 months. Olisthy was reduced completely, clinical symptoms disappeared and there was no serious complications. Conclusion This device only required fixation of the slipped and its inferior adjacent vertebral body, and then it causes little influence to the movement of the lumbar spine. The arm of force of the reduction is short, so it is especially indicated for mild and moderate spondylolisthesis.

Objective To Introduce the principle, structure and observe the effects of clinical application of Scofix instrumentation. Methods Scofix instrumentation consists of different size of open up pedicle screws, open up pedicle hooks, connecting rods, blockers and devices of transverse connection. The open up pedicle screws can be inserted continuously or intermittently, fixed by the connecting rods in the scoliotic segments, and then distraction, compression and derotation manipulation can be performed to correct the spinal deformity. Thirty three patients were treated with this methods. The average age at surgery was 14.4 years. The mean preoperative Cobb angle in idiopathic and congenital scoliosis was 70 and 68 degrees,respectively. According to the degree of deformity and spinal flexibility, the correction was done at one setting or in stages. Results Postoperative Cobb angle and the corrective rate in 19 cases of idiopathic scoliosis were 29.4?and 59.1%, respectively while in 14 cases of congenital scoliosis the figures were 33.3?and 52.3%, respectively. No severe complications occurred. Conclusion Scofix instrumentation which is designed by the principle of CD instrumentation and in conformity with the spinal structural features of Chinese adolescence has the function of distraction, compression and derotation and can be used for internal fixation of scoliosis in different ages. Because of the high risk and the great difficulty, the thoracic pedicel screws should be used carefully, and can be replaced by pedicle hooks if necessary.

Objective To assess the effect of aspirin for the chemoprevention of colorectal adenomas by meta analysis of the published literature.Methods Cochrane strategy in combination with manual search was used to identify previously published randomized controlled trials by searching PubMed,EMBase,Cochrane Library,China Journal Full-text Database(CNKI),Chinese Scientific Journal Full-text Database (CSJD) and Chinese Biomedical Literature Database (CBM).Results Six randomized controlled trials involving a total of 2 858 patients were studied.Of the six trials,two trials were performed in China,four trials were in the Europe and the United States.Some sufficient evidence were found to support that aspirin could prevent of colorectal adenomas compared with placebo group ( P =0.003,RR =0.66,95％ CI:0.50-0.86).No adaquate evidence supported the role of aspirin in the prevention of development of colorectal cancer ( P =0.29,RR =0.65,95％ CI:0.30-1.44).High-dose aspirin ( P =0.10,RR =0.85,95％ CI:0.71-1.30 ) and low-dose aspirin could prevent colorectal adenomas compared with placebo group( P =0.02,RR =0.57,95％ CI:0.36-0.90),and a dose-dependent associtation was found.The risk of stroke was higher in any dose of aspirin compared with placebo group ( P =0.04),and the risks of adverse events had no significant differences in all groups.Conclusion Aspirin might prevent the development of colorectal adenomas in individuals,but could not prevent the colorectal cancer.