Finite Element Assessment of the Screw and Cement Technique in Total Knee Arthroplasty.

BACKGROUND: The screw and cement technique is a convenient method used to rebuild medial tibial plateau defects in primary total knee arthroplasty (TKA). The objective of this study was to perform a finite element assessment to determine the effect of different numbers of screws on the stability of TKA and to determine whether differences exist between two different insertion angles. METHOD: Six tibial finite element models with defects filled with screws and cement and one model with defects filled only with cement were generated. Contact stresses on the surface of cancellous bone in different areas were calculated. RESULTS: Compared to the cement-only technique, the stress on the border of cancellous bone and bone cement decreased by 10% using the screw and cement technique. For bone defects with a 12% defect area and a 12-mm defect depth, the use of 1 screw achieved the greatest stability; for those with a 15% defect area and a 20-mm defect depth, 2 screws achieved the greatest stability. CONCLUSIONS: (1) The screw and cement technique is superior to the bone cement-only technique. For tibial defects in which the defect area comprises a large percentage but the depth is less than 5 mm, the screw and cement technique is recommended. (2) Vertical screws can achieve better stability than oblique screws. (3) Screws should be used in moderation for different defects; more is not always better.

[Association of vitamin D receptor gene polymorphisms with susceptibility to bone and joint tuberculosis in Chinese Han population].

OBJECTIVE: To investigate the association between vitamin D receptor (VDR) gene Apa I polymorphism and the susceptibility to bone and joint tuberculosis in Chinese Han population. METHODS: Between May, 2015 and June, 2016, 100 patients with bone and joint tuberculosis and 100 healthy volunteers were recruited concomitantly in Heyuan Hospital of Traditional Chinese Medicine. Vitamin D receptor gene Apa I polymorphisms in these subjects were analyzed using SNaPshot. RESULT: The genotype frequencies of Apa I-AA, Apa I-Aa and Apa I-aa were 51%, 41%, and 8% in the case group and 33%, 55%, and 12% in the control group, respectively, showing significant differences between the two groups (P<0.05). The genotype of Apa I-AA was significantly higher in the case group with an odds ratio (OR) of 2.073 (95% CI: 1.142-3.763). CONCLUSION: The Apa I polymorphisms of the VDR gene are associated with the susceptibility to bone and joint tuberculosis in Chinese Han population, and individuals with a Apa I-AA genotype are at greater risks to develop bone and joint tuberculosis.

[Fabrication of a new composite scaffold material for delivering rifampicin and its sustained drug release in rats].

OBJECTIVE: To fabricate a new composite scaffold material as an implant for sustained delivery of rifampicin and evaluate its performance of sustained drug release and biocompatibility. METHODS: The composite scaffold material was prepared by loading poly(lactic-co-glycolic) acid (PLGA) microspheres that encapsulated rifampicin in a biphasic calcium composite material with a negative surface charge. The in vitro drug release characteristics of the microspheres and the composite scaffold material were evaluated; the in vivo drug release profile of the composite scaffold material implanted in a rat muscle pouch was evaluated using high-performance liquid chromatography. The biochemical parameters of the serum and liver histopathologies of the rats receiving the transplantation were observed to assess the biocompatibility of the composite scaffold material. RESULTS: The encapsulation efficiency and drug loading efficiency of microspheres were (56.05±5.33)% and (29.80±2.88)%, respectively. The cumulative drug release rate of the microspheres in vitro was (94.19±5.4)% at 28 days, as compared with the rate of (82.23±6.28)% of composite scaffold material. The drug-loaded composite scaffold material showed a good performance of in vivo drug release in rats, and the local drug concentration still reached 16.18±0.35 µg/g at 28 days after implantation. Implantation of the composite scaffold material resulted in transient and reversible liver injury, which was fully reparred at 28 days after the implantation. CONCLUSION: The composite scaffold material possesses a good sustained drug release capacity and a good biocompatibility, and can serve as an alternative approach to conventional antituberculous chemotherapy.

Is duration of preoperative anti-tuberculosis treatment a risk factor for postoperative relapse or non-healing of spinal tuberculosis?

PURPOSE: This study evaluated the relationship between spinal TB postoperative recurrence or non-healing and duration of preoperative anti-TB treatment (ATT). METHODS: From January 2004 to January 2013, patients who underwent surgery for spinal TB and met this study's inclusion criteria were retrospectively reviewed. Observed parameters were age, sex, initial ESR, preoperative ESR, degree of ESR change, initial CRP, preoperative CRP, degree of CRP change, duration of preoperative ATT, surgical approach, presence of internal fixation, location of spinal lesion, number of involved segments, duration of operation, and intraoperative blood loss. The data were analyzed by univariate and multivariate analyses for spinal TB recurrence or non-healing to determine related risk factors. RESULTS: A total of 223 patients met the inclusion criteria. There were 84 female and 139 male patients with a mean age of 42.2 years (range 2-85 years). The follow-up period was 18-72 months (average 28.7 months). Among 223 patients observed, 23 patients had postoperative relapse or non-healing (10.3 %) during the follow-up period. Statistical analysis indicated that the location of a spinal lesion was significantly associated with postoperative relapse or non-healing. Risk of postoperative relapse or non-healing in thoracolumbar TB was 2.524-fold (95 % CI 1.026-6.580) that of lumbosacral TB. CONCLUSIONS: Duration of preoperative ATT may not be a risk factor for postoperative recurrence or non-healing of spinal TB. Junctional zones such as the lumbosacral and thoracolumbar junction have a higher recurrence rate than non junctional.

Clinical outcomes after decompressive laminectomy for symptomatic ossification of ligamentum flavum at the thoracic spine.

Ossification of the ligamentum flavum (OLF) is a rare disease that causes acquired thoracic spinal canal stenosis and thoracic myelopathy. The aim of this study was to investigate clinical outcomes of symptomatic thoracic OLF treated using posterior decompressive laminectomy. We retrospectively analyzed the medical records of 22 patients who underwent posterior decompressive laminectomy for symptomatic thoracic OLF. The surgical results were evaluated using the modified Japanese Orthopaedic Association (JOA) scoring system and Hirabayashi recovery rate. The intensity of pain was evaluated using a visual analog scale (VAS). The mean duration of follow-up was 35.6months. The mean JOA score was significantly improved at final follow-up (9.18±standard deviation of 1.53 points [range, 6-11 points]) compared with before surgery (5.64±2.04 points [range, 3-9 points]) (P<0.001). The mean Hirabayashi recovery rate was 65.49% (range, 20-100%). Recovery outcomes were excellent in nine patients, good in eight patients, fair in four patients and unchanged in one patient. No patient was classified as deteriorated. The VAS scores were 2.82±3.08 before surgery and 0.59±1.05 at final follow-up (P=0.001). Surgical complications, which resolved after appropriate and prompt treatment, included dural tear in five patients, cerebrospinal fluid leakage in one patient, immediate postoperative neurologic deterioration in one patient, epidural hematoma in one patient, and wound infection in one patient. Our findings suggest that posterior decompressive laminectomy is an effective treatment for symptomatic thoracic OLF and provides satisfactory clinical improvement, but surgery for thoracic OLF is associated with a relatively high incidence of complications.

Esophageal perforation related to anterior cervical spinal surgery.

Esophageal perforation is an uncommon but potentially fatal complication of anterior cervical spinal surgery. This study aimed to investigate the diagnosis and treatment of cervical esophageal perforation related to spinal surgery. Among 1097 consecutive cases of anterior cervical spinal surgery that were managed at our institution over a 20 year period, five patients with esophageal perforation were identified. We performed a retrospective review of the diagnoses and treatment of esophageal perforation in these five patients as well as another patient who was transferred from another hospital. The esophageal perforations in all six patients were recognized during the early postoperative period. All patients presented with neck pain, dysphagia, odynophagia, coughing, fever and incision swelling and drainage. Diagnosis was confirmed by one or several of the following methods: contrast swallow study; endoscopy; cervical radiographs; or oral methylene blue. Nasogastric tube, intravenous antibiotics, enteral and parenteral nutrition, and open drainage were conducted in all patients. The wound was debrided in three patients, while two had implant removal and primary suture of the perforation. Five patients had a good recovery with healing of the esophagus, while one patient died due to severe pneumonia. The early diagnosis of esophageal perforation related to cervical spinal surgery relies on clinical suspicion and efficient investigation. The selection of appropriate treatment options, which include esophageal rest, antibiotic administration, nutrition support, wound debridement, open drainage, and surgical repair, largely depends on when the perforation is recognized. Early diagnosis and prompt management of this complication are likely to result in a good clinical outcome.

[Expression of hypoxia-inducible factor-1alpha and matrix metalloproteinase-2 in degenerative lumbar intervertebral disc].

OBJECTIVE: To investigate the expression of hypoxia-inducible factor-1alpha (HIF-1alpha) and matrix metalloproteinase-2 (MMP-2) in degenerative human intervertebral disc. METHODS: Specimens of the nucleus pulposus of the degenerative discs were obtained from patients with lumbar disc herniation (experimental group), and those from young patients suffering thoracolumbal vertebral bursting fracture served as the control. The experimental group was divided into three subgroups according to the magnetic resonance imaging (MRI) results. The tissue specimens from all the groups were examined for HIF-1alpha and MMP-2 expressions using immunohistochemistry. RESULTS: The tissues in the experimental group showed significantly higher expressions of HIF-1alpha and MMP-2 than those in the control group (P<0.05), and the expressions increased significantly with the severity of the degenerative changes of the intervertebral discs (P<0.05). A positive correlation was found between the expressions of the HIF-1alpha and MMP-2 in degenerative intervertebral discs. CONCLUSION: HIF-1alpha and MMP-2 may participate in the degeneration of human intervertebral discs, in which process their expressions show a common pattern of enhancement with the progression of the condition.

[Biological characteristics of human degenerative vertebral endplate cells].

OBJECTIVE: To observe the morphology and phenotypes of cells extracted from the endplate in the intervertebral discs and identify the factors affecting their biological characteristic. METHODS: The intervertebral disc endplate were digested enzymatically, and the morphology of the obtained cells was examined under light microscope. Immunhistochemical analysis of collagen II and real-time PCR was carried out, and the morphologies, viability, cell growth, apoptosis and chondrocyte matrix production were compared between the cells isolated from the degenerative and normal vertebral endplates. RESULTS: The cells in primary culture presented with spherical and oval morphology, and the cytoplasm was stained blue with toluidine blue. The morphologies of the cartilage endplate cells and the articular cells were almost identical. All the freshly isolated cells expressed collagen II. The degenerative vertebral endplate cells showed decreased expression of collagen II with increased apoptotic cells as compared with normal vertebral endplate cells. CONCLUSION: The intervertebral disc endplate cells, like articular cartilage cells, express cartilage-specific matrix proteins. Degenerative vertebral endplate cells show decreased cell vitality with increases cell apoptosis.

[Complications of the anterior surgical approach for thoracolumbar spine tuberculosis: causes and countermeasures].

OBJECTIVE: To assess the effect of the anterior surgical approach for thoracolumbar spine tuberculosis and analyzed the causes of the surgical complications and the countermeasures. METHODS: From Jan 1996 to Dec 2005, 120 patients with thoracolumbar spine tuberculosis underwent operations through the anterior approach either following the primary diagnosis (115 cases) or for recurrence (5 cases). RESULTS: Intraoperative pleural rupture occurred in 4 cases, and rupture of the external iliac vein occurred 1 case. Three patients had damages of the T12 dorsal ramus. One patient developed venous embolism of the lower extremity after the operation, two had paralytic ileus and 1 had false diabetes insipidus. Of the 5 recurrent patients, 1 died due to alcoholic cirrhosis and acute liver failure, 1 received a third operation for loosened internal fixation, and 1 had recurrence due to extensive drug resistance (XDR). CONCLUSION: Standardized antituberculous therapy is fundamental for preventing the recurrence of tuberculosis, and individualized antituberculous therapy adjustment according to the results of bacterial culture and drug sensitivity tests can be the most effective means for preventing drug resistance and reducing tuberculosis recurrence.

Artificial nucleus replacement: surgical and clinical experience.

OBJECTIVE: To assess long-term clinical results of prosthetic disc nucleus (PDN) replacement for the treatment of lumbar disc herniation. METHODS: Seventy-two patients with lumbar disc herniation were implanted with a single PDN device from March 2002 to December 2003. Fifty-eight (80.6%) patients attended clinical, functional, and radiographic follow-up examinations for more than 48 months. Independent analysis was performed by careful review of the interviews, operative reports, preoperative and postoperative radiographs, and computed tomography scans or magnetic resonance imaging (MRI). RESULTS: After implantation, a significant proportion of patients experienced pain relief. Improvements were noted in pain intensity, walking distance, neurological weakness, Oswestry and Prolo scores, intervertebral disc height and lumbar mobility. Intervertebral disc height was not well maintained, compared with the preoperative height it decreased 18% (P < 0.001). Several complications were associated with the implantation of PDN, including transient low-back pain, implant dislocation, malposition of the implant, damage to the end plates and subsidence of implant. CONCLUSION: The clinical data show that PDN is preferred and can effectively increase the range of lumbar motion in patients with lumbar disc herniation. However, this study only represents cases in our centre.

[Effect of prosthetic nucleus pulposus replacement on stress distributions of lumbar disc endplate].

OBJECTIVE: To determine the stress distribution on endplate after lumbar prosthetic disc nucleus (PDN) replacement. METHODS: Six fresh lumbar vertebrae with normal Modic classification were harvested. The specimens were used to establish L4-5 intact, nucleotomy, prosthetic nucleus pulposus replacement models. Vertical compression tests were performed with MTS machine at the rate 50 N per second to maximum load of 1300 N. The stress under the endplate were measured directly with accurate pressure sensors. RESULTS: For intact specimens, the stress on the endplate maintained higher in the central zone of the endplate, and decreased gradually to the periphery, and was well-distributed. After nucleotomy, the stress on the central zone of endplate was significantly decreased, and increased stress occurred in the periphery of endplate. After PDN replacement, the stress on the central zone of endplate was found more 15.1% higher than that in intact disc (P < 0.05), and the neighboring zone also showed higher stress measurements. CONCLUSIONS: After lumbar prosthetic disc nucleus replacement, the stress concentration on endplate may occur in the central zone of prosthetic disc nucleus insertion. Therefore, the prosthetic nucleus pulposus with suitable shape, proper biomechanical functions and updated materials need further study.

[Evaluation of the biocompatibility of pectin/poly vinyl alcohol composite hydrogel as a prosthetic nucleus pulposus material].

OBJECTIVE: To evaluate the biocompatibility of pectin/poly vinyl alcohol composite (CoPP) hydrogel for use as a prosthetic nucleus pulposus material. METHODS: The in vitro cytotoxicity of CoPP hydrogel was tested in NCTC L929 cells, which were divided into normal control group, negative control group [treated with poly (vinyl alcohol) hydrogel, PVA], experimental group (treated with CoPP) and positive control group (0.64% phenol). The optical density of the cells on days 2, 4, and 7 of the corresponding treatments was determined and the relative growth rate calculated. For in vivo biocompatibility evaluation, dehydrated CoPP and PVA hydrogel were respectively implanted into the left and right gluteus of SD rats, and the wound healing and general status were observed. The muscular tissues containing the implants were taken 1, 4, and 12 weeks after the implantation for gross observation and microscopic observation of the inflammatory cell infiltration (ICI) and formation of the fibrous capsulation around the implants. RESULTS: The L929 cells incubated with PVA and CoPP group both grew well, with relative growth rate over 80% and 75%, respectively. The cytotoxicity of PVA and CoPP was both lower than grade 1. In contrast, the relative growth rate in the positive control group was below 24%, with cytotoxicity over grade 4. In the SD rats, ICI of grade IV occurred in the muscular tissues around the PVA and CoPP implants at 1 week without formation of complete capsule, and at 4 weeks, ICI was lowered to grade 1 with grade 4 capsular reaction. Till week 12, the ICI and capsular reaction were both first grade. CONCLUSION: CoPP hydrogel has in vitro grade 0 or 1 cytotoxicity and causes only mild inflammation after implantation in rats, suggesting good biocompatibility of the material.

[Perioperative complications of single-stage surgical management for spinal tuberculosis].

OBJECTIVE: To analyze the causes of perioperative complications of single-stage surgical management for spinal tuberculosis. METHODS: One hundred and twenty patients with thoracic, lumbar and lumbosacral spinal tuberculosis were treated by single-stage surgical management from January 1997 to January 2006 in our unit, including seventy-five males and forty-five females. The mean age was 34.5 (range 17 to 68) years old. The lesion ranged from T(6) to S(1). The anterior procedures of anterior debridement, interbody fusion and anterior fixation were carried out in sixty-five cases, posterior procedures in twenty-six cases, and combined anterior and posterior procedures in twenty-nine cases, respectively. The complications that occurred during surgical procedure and 1 month after operation were recorded. Underlying causes were analysed. RESULTS: There were 10 cases (8.3%) were recorded of mild to severe complications during perioperative period in 120 patients. The complications and underlying causes were as follows: (1) A patient died from liver failure and blood coagulation dysfunction after operation due to inappropriate surgical timing (n = 1), in which case the patient with lumbosacral spinal tuberculosis also suffered from alcoholic liver sclerosis and dysfunction. (2) False diabetes insipidus (n = 1) and deep vein thrombosis of lower limbs (n = 1) occurred as result of surgical trauma. (3) Tear of iliac vein (n = 1) occurred with lumbosacral spinal tuberculosis because of unclear anatomical relationships when anterior debridement was performed. Injury of lumbar nerve roots (n = 3) and hemothorax (n = 1) also occurred due to mispractice of surgical procedures. (4) Paralysis intestinal obstruction and hypokalemia (n = 2) occurred after anterior procedures for lumbar spinal tuberculosis as a result of other reasons. CONCLUSIONS: Improper perioperative care will lead to complications of single-stage surgical procedures for spinal tuberculosis. Emphasis should be put on preoperative evaluation, surgical planning, and postoperative caring for prevention of complications.

[Analysis of the long-term outcome of anterior approach surgery on cervical spondylotic myelopathy].

OBJECTIVE: To investigate the long-term efficacy of anterior approach surgery on cervical spondylotic myelopathy and factors affecting prognosis. METHODS: The data in 116 patients suffered from cervical spondylosis from January 1992 to December 2000 were reviewed, including 80 male cases and 36 female cases, whose age ranged from 36 to 76 years (mean, 51 years). The preoperative course of disease was 2 months to 20 years (mean, 19 months). There were 65 cases (56.0%) with single segments involved, 44 cases (37.9%) with two segments, 7 cases (6.0%) with three segments. Ninety-eight cases were onset slowly, 18 cases with no remote cause and aggravating quickly. Three kinds of surgeries were performed: anterior cervical decompression and autoiliac bone interbody fusion, anterior cervical decompression and fusion with threaded fusion cage, anterior cervical decompression and autoiliac bone interbody fusion with anterior screw-plate system. Improvement in spinal cord function was assessed using the Japanese Orthopaedic Association (JOA) scoring system, the long-term efficacy and influential factors were also analyzed. RESULTS: The mean follow-up time was 7 years and three months (5 - 12 years). The mean preoperative JOA score was 9.34 +/- 1.81. The mean postoperative JOA score was 10.35 +/- 1.85. At the final follow-up, the JOA score was 14.09 +/- 1.90 and the recovery rate was 63.2%. Among the total patients, 27 cases were excellent, 47 cases were fine, 23 cases were good, 19 cases were poor, the fineness rate was 63.8%. The long-term efficacy of anterior approach surgery has close correlations with time of course, age of onset, preoperative spinal cord function and the number of affected segments, but has no correlations with modes of fusion and internal fixation. CONCLUSIONS: The patients will be attentively observed while having a definite diagnosis of cervical spondylotic myelopathy. The good long-term results will be obtained after early anterior cervical decompression and fusion.

[Risk factor analysis of early complications following anterior spine surgery in 258 cases of cervical spondylotic myelopathy].

OBJECTIVE: To define the possible risk factors for early complications following anterior surgery for cervical spondylotic myelopathy. METHODS: Two hundred and fifty-eight cases of cervical spondylotic myelopathy receiving anterior surgery between January 1992 and December 2003 were reviewed and the gender, age and other factors of the patients were analyzed with single-factor analysis and multiple logistic regression. RESULTS: Complications arising in the early stage after the surgery were found in 19 cases (20 events), with an incidence rate of 7.4%;. Single-factor analysis showed that the two factors, paralysis and surgical approaches, were correlated with the early complications, and paralysis was identified as the major factor determining the occurrence of these complications by multiple logistic regression. CONCLUSION: Paralysis is the major factor related to the occurrence of early complications following anterior surgery for cervical spondylotic myelopathy, which reiterates the importance of proper perioperative management.

[Changes of nitric oxide content and nitric oxide synthase activity during rabbit cartilage endplate degeneration].

OBJECTIVE: To study the role of nitric oxide (NO) and nitric oxide synthase (NOS) in the degeneration of rabbit cartilage endplate (CEP). METHODS: Twenty-four New Zealand rabbits were divided into experiment (n=12) and control (n=12) groups, and in the former group rabbit models of lumbar CEP degeneration was established by resection of all the lumbar supraspinous and interspinous ligaments and excision of part of the zygapophyseal joints followed by detachment of the posterior paravertebral muscles from the lumbar vertebrae. Lumbar X-ray was performed in both groups 12, 24 and 36 weeks after operation, respectively. The content of NO and NOS activity in the CEP were also measured. RESULTS: X-ray of the CEP reveal gradual calcification of the cartilage endplate with the elapse of time, which was more obvious in the experiment group. The content of NO and NOS activity was significantly increased in the experiment group after the operation (P<0.05), but their difference between the measurements at 24 and 36 weeks postoperatively was not obvious (P>0.05). CONCLUSION: NO may play an important role in the development and progression of rabbit cartilage endplate degeneration.

[Treatment of spondylolysis and spondylolisthesis with posterior STB thoracolumbar transpedicular screw-plate spine fixation system].

OBJECTIVE: To observe the clinical effect of a self-designed posterior STB thoracolumbar transpedicular screw-plate system in the treatment of spondylolysis and spondylolisthesis. METHODS: This STB screw-plate system is developed with titanium alloy (TC4, Ti6Al4V). During December, 1999 and January, 2001, this system was applied in 51 cases, including lumbar spondylolysis and spondylolisthesis (36 cases), degenerative lumbar instability (15 cases). The patients were aged 22 - 78 years, mean age: 47.5 - years; among them there were 14 male cases, 37 female cases; There were 15 cases degenerative spondylolisthesis with grade I-II slip, 36 cases of spondylolysis and spondylolisthesis, including 34 cases with grade I-II slips and 2 cases with grade III slips; single level of 33 cases, two levels 3 cases. Decompression was performed for the 43 cases with interbody fusion using iliac crest or bilateral-lateral fusion using demineralized bone matrix and 8 cases were fixed with demineralized bone matrix fusion without decompression. RESULTS: All the operations heeded about 60 - 120 minutes, and during the operations bleeding amounts were 200 - 500 ml. The cases completely recovered to work or normal action after 3 months of surgeries. 46 of all cases were achieved to satisfactorily reduction and clinical effect, 5 cases of grade II-III remained incomplete reduction (grade I slip). CONCLUSION: This STB system has advantages of biomechanical stability and reduction capability and its effect in clinical application is undoubtedly positive.

[Growth factor and regeneration of intervertebral disc].

OBJECTIVE: To review research progress of the relation between growth factor and repair of intervertebral disc. METHODS: The recent articles on growth factor and repair of intervertebral disc were extensively reviewed. The expression of growth factor in intervertebral disc and the effect of growth factor on disc cells were investigated. RESULTS: Some growth factors play roles in the development and degeneration of intervertebral disc. Exogenous growth factor can increase proliferation of disc cells and production of proteoglycans and collagens. Gene of growth factor can be transferred to intervertebral disc cell by adenovirus. CONCLUSION: Growth factor plays an important role in the regulation of development and degeneration of interertebral disc. The above results show that the feasibility of usage of growth factor in the treatment of disc degeneration and in repair and reconstruction of disc.

[Cloning and expression of insulin-like growth factor-1 platelet-derived growth factor-AA, and tumor growth factor beta1 genes in adenovirus vector].

OBJECTIVE: To establish recombinant adenovirus highly expressing genes of insulin-like growth factor-1 (IGF-1), platelet-derived growth factor-AA (PDGF-AA), and tumor growth factor beta1 (TGF beta 1) to be used in gene therapy. METHODS: Normal human osteoblasts were obtained from cancellous bone of lilium left from bone grafting and then cultured. Total RAN was extracted and IGF-1, PDGF-AA, and TGF beta 1 cDNAs was obtained by RT-PCR. Vector p-Shuttle containing these cNDAs was cloned into adenovirus and then the recombinant adenovirus was transfected into HEK293 cells. Recombinant adenovirus containing reporter gene LacZ was used in control group. Western blotting was used to detect the expression of these growth factors. Human osteoblasts were cultured and transfected with recombinant adenovirus. MTT method was used to detect the proliferation of the cells. Paranitrophenol method was used to examine the activity of alkaline phosphatase (ALP) in osteoblasts. RESULTS: Expression of IGF-1, PDGF-AA, and TGF beta 1 cDNA and expression of IGF-1, PDGF-AA, and TGF beta 1 proteins were found in HEK293 cells transfected with the recombinant adenovirus and not in the control HEK293 cells. The proliferation and ALP activity of osteoblasts transfected with the recombinant virus were significantly increased in comparison with those of the control osteoblasts (all P < 0.010). Immunohistochemical staining showed significant brown particles in the osteoblasts transfected with the recombinant virus and none in the control osteoblasts. CONCLUSION: The recombinant adenovirus thus constructed expresses the proteins of several growth factors with bioactivity in human cells and can be used as a satisfactory gene tool.

[One-stage surgical management for spinal tuberculosis].

OBJECTIVE: To evaluate the clinical efficacy of one-stage surgical management for spinal tuberculosis. METHODS: Fifty-seven patients with thoracic, thoracolumbar and lumbar spinal tuberculosis were treated surgically by a single stage procedure from Jan 1996 to Jan 2001, including anterior resection, interbody outografting and anterior instrumentation in 35 cases, posterior debridement and posterior instrumentation in 16 cases, and posterior instrumentation and anterior resection plus interbody autografting in 6 cases. Titanium-alloy spinal implants were used in 38 cases and stainless steel implants in other 19 cases. Except for three patients, other 54 patients were followed up for one to five years (mean 2.2 years). RESULTS: All these patients had their incision healed by first intention without chronic infection or sinus formation, and no recurrence of spinal tuberculosis was noted in any patient during the follow-up period. Kyphosis correction were achieved by 21.6 degrees on the average postoperatively. There was a mild loss (2 degrees - 4 degrees) of kyphosis correction during follow-up period. Spinal solid fusion at the interface between the graft and adjacent vertebral bodies was shown radiologically in 3.8 months on the average. CONCLUSION: One-stage surgical management has more advantages in that it can completes all the aspects of surgical treatment for spinal tuberculosis. Anterior or posterior instrumentation with titanium-alloy or stainless steel spinal implants is safe, The selection of one-stage surgical procedure should be planed individually.