Study on biocompatibility of carbon-based composites / 生物医学工程学杂志

Silicon carbide (SiC) film and silicon dioxide (SiO ) film were deposited on the surface of carbon/carbon composite (C/C) by low pressure chemical vapor deposition (LPCVD). The biocompatibility of the three carbon-based composites, e. g. C/C, C/C-SiC, C/C-SiO were investigated by cytotoxicity test, cell direct contact and cell adhesion experiments. Cytotoxicity, cell direct contact and cell adhesion showed that the three materials had no toxic effect on mouse fibroblasts (L929 cells). However, the particles dropped off from the three materials had a great impact on evaluation accuracy of the thiazolyl blue (MTT) test. More the particles were lost, more growth inhibition to L929 cells. The evaluation accuracy of MTT method can be kept with the filtered extract of materials. Furthermore, the results of surface particles shedding experiment showed that the amount of surface particles shed from C/C-SiO was the most, followed by C/C and C/C-SiC in 72 hours. Particles shedding curves showed there was a peak reached at eighth hour and then declined to the thirty-sixth hour. The filtrate analysis showed that there was no ion exchange between the three materials and simulated body fluid (SBF) solution. The results of this study on biocompatibility of carbon-based composites have certain guiding significance for their future application in clinical filed.

Clinical therapeutic effect of surgery on upper cervical spinal cord tumors / 中南大学学报(医学版)

OBJECTIVE@#To evaluate the long-term clinical therapeutic effect of polyaxial screw-rod system for posterior cervical arthrodesis on patients with upper cervical spinal cord tumors.
@*METHODS@#From March 2007 to May 2013, 22 patients with upper cervical spinal cord tumors underwent tumor resection and posterior cervical arthrodesis in our institution. The medical records of these patients were reviewed respectively. There were 10 males and 12 females with ages ranging from 16 to 60 years old. Posterior cervical arthrodesis by polyaxial screw-rod was performed at the upper cervical spine (C1-3). All patients were followed-up clinically and radiographically.
@*RESULTS@#The average follow-up was 65.5 months. Twenty-two patients were enrolled and a total of 114 screws were placed in this study. Histopathology revealed neurinoma, meningioma, ganglioneuroma and ganglioglioma in 16, 3, 1 and 1 case (s), respectively. The mixed tumor with component of ganglioneuroma and neurinoma was observed in 1 case. All patients received tumor resection and posterior athrodesis by polyaxial screw-rod system. Cervical kyphosis was encountered in one patient and this patient suffered the recurrence of tumor. Solid fusion was achieved in all patients. The average postoperative Japanese Orthopaedic Association (JOA) score was 13.9 and the average recovery rate was 51.4%. Neurologic deterioration was found in 2 patients. No complications, such as spinal cord or vertebral artery injury, postoperative radiculopathy or instrumentation failure, were observed.
@*CONCLUSION@#The long-term clinical therapeutic effects of posterior cervical arthrodesis using polyaxial screw-rod system on upper cervical spinal cord tumors are satisfactory, with no severe complication.

Factors and revision strategy for failure of thoracolumbar spine internal fixation after burst fracture / 中南大学学报(医学版)

OBJECTIVE@#To analyze the reasons for the failure of thoracolumbar spine internal fixation after burst fracture, and to discuss the strategy for revision surgery.@*METHODS@#From January 2005 to September 2010, 21 patients with thoracolumbar burst fracture received revision surgery after the failure of internal fixation. The etiology included loose of the fixation after anterior surgery in 4 patients, involving malunion with severe kyphosis in 1 patient, pedicle screw malposition in 3, fracture of adjacent segment vertebra in 2, broken of the fixation as non-union of the fracture vertebra in 10 comprising obvious kyphotic deformity in 5, and 2 had developing kyphosis for over distraction of the vertebra followed by pseudarthrosis after removing the internal fixation. After the first operation, symptoms remained in 6 patients, deteriorated in 7, light to moderate improved in 8. Surgical procedures such as anterior corpectomy and reconstruction, replacement of the internal fixation and canal decompression, vertebroplasty, and posterior pedicle subtraction osteotomy were directed based on individual situation.@*RESULTS@#Patients were followed-up for 6-68 (27.0±13.2) months, and demonstrated solid fusion 6 to 12 months postoperatively. No failure of the internal fixation reccurred. No major complications or deterioration of neurologic status were noted. At the last follow-up, the improvement of Frankel grade was 0-2 (1.3±0.7). The mean visual analog scale (VAS) dropped down from 7.6 to 2.1, and the mean oswestry disability index (ODI) decreased from 48.7 to 10.3. Preoperative angle of 7 kyphotic deformity patients was 10 degree-75 degree (42.5 degree±15.3 degree), and was improved to -3 degree-10 degree (2.3 degree±3.7 degree). At the last follow-up, the loss of correction was 0 degree-1.3 degree (0.7 degree±0.3 degree), with the correction rate of 92.3%.@*CONCLUSION@#Solid reconstruction of the anterior and middle column of the spine is the imperative procedure to prevent failure of internal fixation in thoracolumbar burst fractures. Revision surgery with reasonable strategy is beneficial and rewarding with few complications.

Signaling of biglycan and cytokines in bovine intervertebral disc cells / 中南大学学报(医学版)

OBJECTIVE@#To evaluate the effect of biglycan on the signaling of cytokines (epidermal growth factor, osteogenic protein-1, and interleukin-1) in bovine intervertebral disc cells.@*METHODS@#Nucleoplasty (NP) and annulus fibrosus (AF) cells of the intervertebral disc tissues were isolated from the tails of young adult bovine. First, the cells were treated in 3 ways: Biglycan alone, cytokines alone (epidermal growth factor, osteogenic protein-1, or interleukin-1), and biglycan combined with cytonkines. Western blot was used to observe the singling of biglycan and cytokines in bovine intervertebral disc cells, and to identify the effect of biglycan on cytokines mentioned above.@*RESULTS@#Biglycan upregulated the signaling (3- 4 folds) with the optimal effect at 10 min and 20 μmol/L both in the AF cells and NP cells. Epidermal growth factor, osteogenic protein-1, or interleukin-1 also upregulated the protein expression in the extracellular matrix of intervertebral disc cells. When combined different biglycan concentrations with epidermal growth factor, osteogenic protein-1, or interleukin-1 to treat the intervertebral disc cells, the concentration of biglycan rose, whereas the cytokine signal decreased both in the bovine AF and NP cells (P<0.01). There was no significant difference between the AF and NP cells.@*CONCLUSION@#Biglycan can adhere to the intervertebral disc cells to activate the extracellular signal-regulated kinase (ERK) pathway and this effect is time and concentration dependent. Byglycan can decrease not only the anabolism effect of epidermal growth factor and osteogenic protein-1, but also the catabolism effect of interleukin-1. This regulatory role of biglycan may be very important to maintain the metabolism balance. Biglycan may be good for the repair of intervertebral disc.

Neurological complications in treatment of severe thoracolumbar spinal deformity with one stage posterior vertebral column resection / 中华创伤杂志

Objective To analyze the neurological complications in treatment of severe thoracolumbar spinal deformity with one stage posterior vertebral column resection (pVCR) and discuss the related risk factors. Methods There were 67 patients with severe thoracolumbar spinal deformity who underwent one-stage pVCR from February 2000 to September 2010.There were 29 males and 38 females at an average age of 31.4 years old(range,14-62 years).There were 21 patients at age less than 18 years old and 46 at age more than 18 years old.Patients were divided into four pathological types:severe scoliosis group(n=11,mean Cobb angle 90.4°),kyphoscoliosis group(n=25,mean scoliosis 94.5°,and mean kyphosis 65.5°),angular kyphosis group(n=28,mean kyphosis 74.3°)and global kyphosis group(n=3,mean kyphosis 91.1°).of all the patients,59 patients underwent primary surgery and eight underwent revision surgery.Surgical methods included posterior apex vertebral column resection,segemental pedicle screw fixation and correction as well as 360° bone fusion.Neurological complication was statistically analyzed. Results The average follow-up was 14 months (range,3-69 months),which showed severe neurologic complication in eight patients(11.9%)after surgery.Severe neurologic complication occurred in three patients (4.5%),among whom one patient presented delayed complete paraplegia 23 hours after surgery.Five patients had mild neurologic deficits(7.5%),the incidence of which was higher than 23.1%for thoracic osteotomy (P0.05). Conclusions pVCR is an effective surgical method for the correction of severe thoracolumbar spinal deformity.The neurological complications,however,should be paid attention to the surgeons.The risk factors for neurologic complications include improper manipulation,massive blood losing,preoperative neurologic compromise,osteotomy at thoracic rein,multi-level vertebrectomy,revision surgery and severe kyphosis.

Complication of thoracic pedicle screw fixation in spinal deformities / 中南大学学报(医学版)

OBJECTIVE@#To analyze the etiology and prevention of complications related to the pedicle screw technique in the treatment of thoracic scoliosis.@*METHODS@#There were 183 thoracic deformity patients 110 idiopathic scoliosis, 32 adult scoliosis, 28 congenital kyphoscoliosis, 8 Marfan syndrome with scoliosis, and 6 others. All patients' Cobb angles were evaluated preoperatively, intraoperatively, and postoperatively by roentgenograms. The deformity correction rate was calculated. All radiographic evaluations were carried out in a double-blind fashion. The complication rate was analyzed perioperatively and postoperatively.@*RESULTS@#The deformity correction rate was 72%, better than others treated with hook-rod system. The perioperation complication rate was 8.4% (pedicle fracture 1.5%, infection 3.8%, pneumothorax and plural effusion 1.6%, transitory neurological damage 0.5%, and over-bleeding shock 1%). The complication rate at follow-up was 3.6% (infection 0.5%, fatigue fracture 1%, loss of deformity correction 1.6%, and transitory neurological damage 0.5%). Compared with those treated with hook-rod system, the perioperation complication rate, loss of deformity correction, permanent damage, and complications related to the internal fixation were all low.@*CONCLUSION@#The complication rate of pedicle screw fixation system was low in the treatment of thoracic deformity. When surgeons are thoroughly familiar with the technique and related pathoanatomy, and with the spinal cord function wardship by SEP, complications related to the pedicle screw technique in the treatment of thoracic scoliosis will be well controlled.

Accuracy of free-hand thoracic pedicle screw placement in severe idiopathic scoliosis via CT scan / 中南大学学报(医学版)

OBJECTIVE@#To analyze the accuracy of free-hand thoracic pedicle screw placement in severe idiopathic scoliosis via CT scan.@*METHODS@#Twenty patients with complete CT data were chosen out of 58 patients of severe idiopathic scoliosis from June 1996 to December 2006. The Cobb angle of the main thoracic curve was from 82 degree to 142 degree (96.3 degree +/- 14.3 degree). The kyphotic angle in the main curve was 66.2 degree +/- 12.4 degree. The placement of thoracic pedicle screw was completed free-handedly, and the accuracy of screws placement was evaluated with CT thin-slice scan postoperatively.@*RESULTS@#Altogether 174 thoracic pedicle screws were inserted, 157 (90.2%) of which were fully contained within the cortical boundaries of the pedicle.The other 17 screws (9.8%) were misplaced in 9 patients: 11 screws (6.8%) were lateral, 9 of which had a breach 0.05). There was no neural complication in all patients.@*CONCLUSION@#It is fairly accurate place thoracic pedicle screw in severe idiopathic scoliosis free-handedly, with some misplacements.