Objective To investigate the causes and clinical significance of cement leakage into disc space during kyphoplasty. Methods Since 2002, 178 patients with osteoporotic vertebral compression fractures underwent kypboplasty and 15 of them were detected intradiscal cement leakage and followed up more than 2 years (mean 2 years and 8 months). The mean injection of cement in these patients was 4.2ml.The series comprised 10 females and 5 males, with an average of 71.2 years old ( range, 54～84 years old).Visual analog scale was used to score back pain pre- and postoperatively. The height and MRI index of the involved disc were recorded and compared. Results The discs involved were as following: T10-11 for 4 cases,T11-12 for 1, T12L1for 4, L1-2 for 2, L2-3 for 3, L3-4 for 1. Cement leakage was detected in the disc above the fractured vertebrae in 10 cases, and in the disc below the fractured vertebrae in 5 patients. The back pain significantly alleviated and the average visual analog scale (VAS) score was decreased from 8.5±2.1 preoper-atively to 3.3±1.4 postoperatively (P< 0.05). The anterior disc height was (5.1±2.1)mm preoperatively and (4.8±1.9) mm at the final follow-up, the middle disc height was (7.4±3.2) mm preoperatively and (7.3±2.9) mm at the final follow-up, the posterior disc height was (4.9±2.5) mm preoperatively and (5.0±1.8) mm at fi-nal follow-up, the heights of intervertebral space were well maintained. The signal intensity decreased and became inconsistent in some discs, and the preoperative MRI index significantly decreased from 25482.4± 3467.5 to 18927.6±2519.4 at the final follow-up (t=1.967,P< 0.05). Conclusion Pain relief is impressive in patients with intradiseal cement leakage during kyphoplasty. However, cement leakage into disc space may accellerate the process of disc degeneration.

Objective To evaluate the effects of nutritional status on wound healing after hip fracture in the elderly. Methods From July 2002 to December 2004, 127 patients with hip fracture who were older than 65 years were treated surgically in our department. Their preoperative nutritional status was reviewed. There were 69 males and 58 females, with an average age of 72.7 years (from 65 to 99 years). 60 cases had femoral neck fractures, and 67 cases had intertrochanteric fractures. The parameters indicative of nutritional status (serum albumin, serum transferrin and total lymphocyte count levels) at the time of admission were assessed, along with Rainey McDonald nutritional index and age. Suture removal was performed on postoperative day 14. Results Delayed wound healing complicated 31 of the 127 cases. The preoperative serum transferrin levels were significantly lower in patients who subsequently had delayed wound healing. Only preoperative serum transferrin levels( P

Objective To evaluate the efficacy and safety of balloon kyphoplasty in the treatment of painful multi-vertebral osteoporotic compression fractures. Methods From October 2002 to April 2007, 42 patients (96 vertebrae) with painful multi-vertebral osteoporotic compression fractures underwent kyphoplasty. The group included 14 men and 28 women with an average age of 72.5 years (range 56-91 years). Each pro-cedure included insertion and insertion of balloon, fracture reduction and cement filling under "C"-arm monitoring. Preoperative and postoperative pain level, SF-36 score, vertebral height restoration, local kypho-sis correction and complications were recorded and analysed. Results All 42 patients tolerated the opera-tion well and were followed up for average 31.4 months (range 12-71 months). The mean VAS pain score decreased significantly from 7.1±2.4 preoperatively to 2.7±1.3 postoperatively, the mean height of anterior and medial vertebral body were (1.8±0.5) cm, (1.6±0.6) cm preoperatively and (2.3±0.6) cm, (2.2±0.7) cm postoperatively. No significant change of posterior vertebral height was recorded postoperatively.The mean correction of local kyphosis was 9.2°at each level. 6 of 8 subscahs measured by SF-36, including physical function, role function, bodily pain, vitality, role emotion, mental health, were significantly improved by the operation. Complications were found in 7 patients including 6 cases of cement leakage with no clinical symptoms (intradiscal cement leakage in two cases, paravertebral vessel leakage in two cases, paravertebral leakage in one case and cement leakage into canal in one case), and 1 case of pulmonary embelization with symptoms relieved after conservative treatment. Conclusion Kyphoplasty is effective and relatively safe for multi-vertebral osteoporotic compression fractures.

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.

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 evaluate the long term outcome of spondylolytic spondylolisthesis treated with Steffee system and posterolateral fusion. Methods Thirty- four patients were followed up for an average of 77.2 months. The follow- up study include slipping percentage, slipping angle, heights of intervertebral space and foramen, fusion rate, screw broken rate and clinical outcomes. Results 1) Solid fusion was obtained in 88.2％ of patients. screw broken rate was 2.9％ . 2) Comparison of pre- and post- operative slip showed correction rate of 45.1％ . The heights of intervertebral space and foramen increased, slipping angle decreased. 3) During the period of follow- up, recurrence of deformity was found. 4) The subjective outcome was better than the objective outcome. Conclusion 1) Lumbar spondylolytic spondylolisthesis with radicular symptom need complete decompression and reduction as much as possible. 2) A positive slipping angle indicates significant shearing force and the need of an interbody fusion to restore the weight- bearing capacity. 3) Objective criteria is more suitable to evaluate surgical outcome.

Objective To study the method of percutaneous vertebroplasty (PVP) and investigate its clinical efficacy. Methods Tweenty five cases (13 patients with painful osteoporotic vertebral fractures, 8 cases with metastatic neoplasms and 4 cases with hemangionmas) were treated by the injection of polymethyl methacrykate (PMMA) under DSA fluoroscopic guidance. the time of follow up ranged from 1 15 months. Results The procedure was successful in all patients. Among 25 patients, 18 experinced with complete relief of pain, 6 with conspicuous relief, 1 with no significant change. Two patients showed transient symptom of radiculopathy and no clinical complication in others. Conclusions PVP is a safe and feasible treatment for patients with hemangiomas and vertebral fractures caused by malignancies and osteoporosis.