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<p><b>OBJECTIVE</b>To evaluate the structural characteristics and biocompatibility of a novel nano-Ta-Ti alloy rod for its potential application in internal fixation.</p><p><b>METHODS</b>Ta coating of a Ti alloy rod with nano-Ta (tantalum) powder was performed using laser melting with symmetrical grooves repleted with nano-Ta powder along the whole length. The microstructure of the cross section of Ta-Ti alloy rod, pore diameter and components of the coating were analyzed using scanning electron microscopy. The influence of this nano-Ta-Ti alloy on proliferation and differentiation of MC3T3-E1 cells was evaluated by MTT cytotoxicity test and ALP activity test.</p><p><b>RESULTS</b>Under scanning electron microscope, the Ta-coating surface presented with a gross porous (200-300 µm) structure with dense fusion between Ta particles, and no new element was produced after laser melting. Biocompatibility evaluation showed that Ti alloys with and without Ta coating both promoted the proliferation of MC3T3-E1 cells, but the coated alloy showed better performance and obviously promoted the differentiation of the osteoblasts.</p><p><b>CONCLUSION</b>Alloying between Ta and Ti can be accomplished successfully by laser melting technique, and the alloy obtained has ideal surface structure and good biocompatibility.</p>
Subject(s)
Animals , Mice , 3T3 Cells , Alloys , Biocompatible Materials , Cell Differentiation , Cell Proliferation , Materials Testing , Microscopy, Electron, Scanning , Osteoblasts , Cell Biology , Porosity , Tantalum , TitaniumABSTRACT
[Objective] To assess the outcomes of lumbar spinal pedicle subtraction osteotomy on single segment for correction of kyphosis in ankylosing spindylitis.[Methods]15 patients were treated with L2 or L3 pedicle subtraction osteotomy and internal fixation by pedicle screw system.All the patients underwent X-ray examinations in standing position before and after the operations.The angles in different part of the sagittal planes were measured and the preoperative and postoperative differences were compared.[Results]All the operations were well complete.The mean time of operations was 3h and the mean bleeding was 840 ml.The lumbar lordosis angle increase from(14.5?15.5)?to(48.4?11.9)?,the total spinal kyphosis angle and the thoracolumbar kyphosis angle improve from(36.1?14.7)?and(30.7?9.3)?to(0.2?14.2)?and(23.7?12.3)? respectively,the sacral slope increase from(12.0?12.7)?to(28.9?8.8)?,whereas thoracic kyphosis angle remained relative stable.[Conclusion]Lumbar spinal pedicle subtraction osteotomy on single segment is a satisfactory and reliable technique for correction of kyphosis in ankylosing spindylitis and the average correction of lumbar lordosis was 33.9?.
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[Objective]To analyze the reasons and counter treatment of complication after prosthetic disc nucleus implantation.[Method]From Feb 2002 to Aug 2004,80 patients of lumbar disc herniation were implanted with one single PDN device at our centre.65 patients of them came to the clinical,functional,and radiographic follow-up examinations,magnetic resonance images and follow-up records of all patients were reviewed carefully.They were divided into three groups.Group A:30 cases had at least 24 months follow-up data.Group B:23 cases had at least 36 months follow-up data.Group C:12 cases had at least 48 months follow-up data.[Result]After implantation,device migrations were noticed in 3 patients.24 cases experienced low back pain.In 24~48 month follow-up,the MR images of 39 patients had shown the abnormal signal pattern of the endplate where PDN-solo was implanted,even 32 of them had been found subsidence.In Group A,the height of intervertebral disc at the 24 month follow-up was decreased 4%.In Group B,at 36 month follow-up,it was decreased 12%.In Group C,at 48 month follow-up,it was decreased 18%.[Conclusion]After follow-up,the clinical effect of PDN is preferred.However,the complications of device dislocation,device subsidence remain problems that must be highlighted.This study suggested that the complications of PDN are serious.Therefore,the proper selecting patients for PDN replacement are crucial for good results.The indications for PDN must be restricted.
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[Objective]To study the role of nitric oxide on the degeneration of the cartilage endplate(CEP).[Method]Twenty-four New Zealand rabbits were divided into experiment and control groups.In the experiment group,the model of lumbar CEP degeneration was established by resection of all lumbar supraspinous and interspinous ligaments,excision of parts of zygapophysial joints and detachment of the posterior paravertebral muscles from lumbar vertebraes.Mechanical instability of the lumbar spine could induced the process of CEP degeneration.The X-ray examination of lumbar spine was examined by at 12,24 and 36 weeks with or without operation,respectively.Changes of the ultrastructure of CEP were also observed by scanning electron microscope(SEM) during this process,and the content of IL-1?,IL-6,TNF-? in the CEP were also detected during the periods.[Result]X-ray graph showed that the CEP calcified gradually with time increasing,and those of the experiment groups calcified more obviously than those of the control groups.The SEM showed that collagen fibers became thin,irregular and fissured and the content of proteoglycan decreased severely with the elapse of time.The changes in experiment groups were more obvious than those in control groups.The content of IL-1?,IL-6,TNF-? had a significant difference between the experiment groups and the control groups(P0.05).[Conclusion]It implies that inflammatary cytokin may play an important role in the development and progression of the degeneration of cartilage endplate.
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OBJECTIVE: To compare the biomechanical differences among the atlantoaxial transarticular screw fixation (Magerl) and other posterior fixation techniques. METHODS: Seven preserved atlantoaxial-complex specimens were harvested and fixated with Magerl, Magerl plus Gallie wiring, Magerl plus Brooks wiring, pure Brooks, pure Gallie, and Halifax interlaminar clamping fixation, respectively. The torque for every fixation technique was measured at the point of five-degree rotation of the atlantoaxial joint. RESULTS: The torque for Magerl was 6.59 Nmplus minus1.14 Nm, which was significantly higher than any other pure posterior techniques including Gallie (1.74 Nmplus minus0.31 Nm). Brooks (4.06 Nmplus minus0.48 Nm) and Halifax (3.44 Nmplus minus0.87 Nm) (P<0.01), but less than Magerl plus brooks (9.94 Nmplus minus1.45 Nm) (P<0.01). No statistically significant difference was found between Magerl and Magerl plus Gallie wiring (7.61 Nmplus minus1.10 Nm) or between Brooks and Halifax. CONCLUSIONS: Compared with other pure posterior fixation techniques the atlantoaxial transarticular screw fixation technique provides more torsion-resistance capacity. It is also suggested that combined Gallie wiring do not add any biomechanical superiority to this technique.
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Objective To discuss the selection of surgical procedures for the treatment of spinal tu-berculosis according to the status of segmental stability of the spine. Methods One hundred adult patients with spinal tuberculosis were treated surgically between January 1998 and December 2003. There were 57 males and 43 females with an average age of 39.4 years and an average history of 16 months. The lesion ranged from T2 to S 2, and involved single vertebral body in 3 cases, double vertebral bodies in 66 cases, and more than two vertebral bodies in 31 cases. Of 100 cases, 32 were with neurological dysfunctions, and 65 were accompanied by kyphotic deformity with an average Cobb angels of 36.4? (20? to 48?). Preoperative chemotherapy of four drugs lasted more than two weeks. Three surgical procedures were performed according to the status of segmental stability of the spine: 12 cases without spine instability underwent single debride-ment, 8 cases of spine instability with debridement and interbody fusion, and 80 cases of significant insta-bility with debridement, fusion and internal fixation. Results All patients' incision healed without chronic infection and sinus formation. 95 patients were followed up with an average of 2.9 years ranged 1 to 77 years except 5 patients lost at follow up. 68 cases with anterior fusion achieved solid fusion in average 3.5 months. 65 cases with kyphotic deformity had an average correction of 20.2? postoperatively, and 2? to 4? loss during follow-up. 32 cases with neurological deficits had an improvement of neurological function postoperatively. One patient of L 4,5 tuberculosis treated with anterior debridement, fusion and instrumentation recurred at 7 months due to an inadequate postoperative chemotherapy of 6 months, and healed with a continuous chemotherapy for 18 months, However, satisfactory clinical results were obtained in other patients without any recurrence. A left external iliac vein was torn and repaired successfully in 1 case. Conclusion The maintenance of segmental stability has significant effect in the surgical treatment of spinal tuberculosis. Sta-tus of segmental stability of each patient should be evaluated preoperatively. Satisfactory clinical results can be achieved by proper selection of the surgical procedure according to the status of segmental stability.
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Objective To analyze the reasons of early complications in anterior cervical spine surgery and its management. Methods Between Jan 1992 and Dec. 2003, 412 patients underwent anterior cervical surgery. There were 308 males and 104 females with an average age of 45.6 years (18-76). The di-agnosis of these patients included 258 of cervical spondylosis, 138 of cervical injury, 8 of cervical spinal tu-mor and 8 of tuberculosis of cervical spine. The medical history was from 4 hours to 20 years with an aver-age duration of 548 days. Among 412 patients, there were 58 cases (14.1%) with complete paraplegia, 192 cases (46.6%) with incomplete paraplegia and 162 cases without neurological deficits. Anesthesia used in this group of patients were local in 35, cervical plexus block in 52, local associated with cervical plexus block in 6, general in 318 and general associated with cervical plexus block in 1. Three surgical procedures were performed: 1) anterior decompression and interbody fusion with autogenous iliac crest in 33 cases; 2) anterior decompression and interbody fusion with threaded fusion cage in 32 cases; 3) anterior decompres-sion, interbody fusion with autogenous iliac crest and plate fixation in 347 cases. Results Fifty-one early complications occurred in 42 patients and the incidence was 12.37%. 28 patients (6.8%) had complications directly related to the procedure which included superior laryngeal nerve injury in 5, recurrent laryngeal nerve injury in 4, migration of bone graft in 2, infection or haematoma in 4, deterioration of neurological function in 5,nerve root injury in 2, loosening of screw or plate fixation in 2 and esophageal fistula in 1. 23 cases (5.08%) had early complications indirectly related to the procedure. Conclusion In order to reduce the incidence of early complications in anterior cervical spine surgery, make familiarization with anatomy, improvement of surgical skill as well as appropriate perioperative management are essential in anterior cer-vical spine surgery.