AXIS侧板钢板螺钉内固定系统对下颈椎骨折脱位后颈髓功能恢复作用

AIM:To evaluate the methods and results of the AXIS lateral mass screw- plate system in the treating of lower cervical spine injury.METHODS:29 cases of lower cervical vertebrae injury were fixed with AXIS system.All of them were followed- up for more than 1 year.RESULTS:All cases had a good bone union without malformation.We found no complication of the injury to the vertebral arteries or nerves.There was no loosening of the plate and screw. CONCLUSION:AXIS lateral mass screw- plate system has the characteristic of stable,simple and safe and is suitable for the treatment of lower cervical spine injury.

内固定等方法对腰椎峡部不连合并滑脱致下腰痛的缓解作用

AIM: To explore the long-term therapeutic effects of surgical treatmeut foristhnic spondylolisthesis. METHODS: 42 cases of isthunic spondylolisthesiswere analyzed retrospectively among which 13 cases underwent simple lum-bar interlaminar bone implant and 29 cases underwent transpecdicular fixationcombined with bone implantation. Assessment was made according to JOAstandards before and after treatment. RESULTS: At a 3 years of follow-upassessment, the functional outcome in transpedicular fixation assessed byJOA was excellent and good in 79.3% as compared with the group withoutfixation in which the excellent and good result was 76. 9%. The level of painand functional disability were similar in the two groups, but fusion rate in thegroup with transpedicular fixation was higher than that in group withoutit. CONCLUSION: Surgical treatment for isthmic spondylolisthesis improvesfunction and relieves pain.

BACKGROUND:Though the effects of conservative or traditional open reduction and internal fixation in the treatment of thoracolumbar fractures are reliable and satisfactory for most cases, two methods also have shortages. Minimal-invasive percutaneous pedicle screw system provides a new available method. OBJECTIVE:To investigate the clinical effect of Sextant percutaneous pedicle screw system in the treatment of thoracolumbar fractures. METHODS:A total of 55 patients, who had undergone percutaneous pedicle screw fixation using Sextant system (25 patients) or traditional open internal fixation (30 patients) for single-level vertebral body compression fractures in Department of Orthopedics of Renmin Hospital of Wuhan University from February 2011 to January 2013, were enrol ed in this study. RESULTS AND CONCLUSION:Except two patients in traditional open internal fixation group were lost after discharge, al other patients were fol owed up for 8-14 months. Operative time, intraoperative blood loss, postoperative drainage amount and hospital day were better in percutaneous pedicle screw fixation group than in the traditional open internal fixation group (P<0.05). Compared with preoperation, the sagittal Cobb angle, visual analogue scale and Oswestry disability index after operation were significantly lower (P<0.05), while anterior vertebral body height ratio was significantly higher in each group (P<0.05). No significant difference was found in terms of correction loss and Oswestry disability index between two groups at 8 months after operation (P>0.05). The results show that percutaneous pedicle screw fixation using Sextant system has a satisfactory outcome in the treatment of thoracolumbar fractures. However, obeying indication strictly is very important for clinical application.

Objective: To explore the clinical ef-fects of external fixation associated with limited internal fixa-tion on treatment of Gustilo grade Ⅲ leg fractures.Methods: From July 2006 to December 2008, 40 cases of Gustilo grade Ⅲ leg fiactures were emergently treated in our unit with external fixation frames.Soft tissue injuries were grouped according to the Gustilo classification as ⅢA in 17 cases, ⅢB in 13 cases, and ⅢC in 10 cases.All the patients were debrided within 8 hours, and then fracture reposition was preformed to reestablish the leg alignment.Limited internal fixation with plates and screws were per-formed on all the Gustilo Ilia cases and 10 Gustilo ⅢB cases at the first operation.But all the Gustilo ⅢC cases and 3 Gustilo ⅢB cases who had severe soft tissue injuries and bone loss only received Vacuum-sealing drainage (VSD).Broad-spectrum antibiotics were regularly used and VSD must be especially maintained easy and smooth for one week or more after operation.Limited internal fixation and transplanted free skin flaps or adjacent musculocutaneous flaps were not used to close wounds until the conditions of the wounds had been improved.Results: The first operations were completed within 90-210 minutes (170 minutes on average).The blood trans-fusions were from 400 ml to 1500 ml (those used for anti-shock preoperatively not included).All the 40 patients in this study were followed up for 6-28 months, 20.5 months on average.The lower limb function was evaluated accord-ing to the comprehensive evaluation standards of leg func-tion one year after operation and the results of 28 cases were excellent, 9 were good and 3 were poor.Conclusion: External fixation associated with limited internal fixation to treat Gustilo grade Ⅲ leg fractures can get satisfactory early clinical therapeutic effects.

Objective: To compsre the biomechanical differences among the atlantoaxiai 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, Mageri plus Brooks wiring, pure Brooks, pure Gailie, and Halifax interlaminar clamping fixation, respectively. The torque for every fixation terhnique was measured at the point of five-degree rotation of the atlantoaxial joint.Results: The torque for Magerl was 6.59 N· m ±1.14 N-m, which was significantly higher than any other pure posterior techniques including Gallie (1.74 N · m ±0.31 N·m). Brooks (4.06 N ·m ± 0.48 N ·m) and Halifax (3.44 N·m ± 0.87 N·m) (P ＜ 0.01), but less than Magerl plus brooks (9.94 N· m ± 1.45 N· m) ( P ＜ 0.01 ). No statistically significant difference was found between Magerl and Magerl plus Gallie wiring (7.61 N·m± 1.10 N·m) or between Brooks and Halifax.Conclusions: Compared with other pure posterior fixation techniques the atlantoaxial transarticular screw fiuation technique provides more torsion-resistance capacity. It is also suggested that combined Gallie wiring do not add any biomechanical superiority to this technique.

Objective: To study the influence of stress-relaxation plate on disorganization and repair of the cortex beneath the plate.Methods: A washer made of viscoelastic polyethylene was placed between the screw and the screw hole of conventional stainless rigid plate (RP) to produce a stressrelaxation plate (SRP). Both SRP and RP were applied to osteotomized tibia in 48 New Zealand rabbits. Healing process of the fracture with either SRP or RP fixation (control) was comparatively studied with polarized light microscopy, in situ hybridization of collagen mRNA and immunohistochemical technique from 2 to 36 weeks postoperatively.Results: The study of plated bone remodeling showed that the degree of cortex osteoporosis beneath the plate was similar between the SRP and RP group within 12 weeks postoperatively. In comparison, the disorganization of bone structure in SRP group happened later and milder than that of RP group, and the repair process began at 12 weeks after implantation. As a consequence, the absorption cavities became smaller and the structure of collagen fibers became well oriented along with these changes by polarized light microscopy. In addition to these, the in situ hybridization analysis of collagen genes and the immunohistochemical study of type Ⅰ , Ⅲ collagen showed that the osteoblasts lying on the surface of absorption cavities expressed and synthesized type Ⅰ collagen at 8 to 12 weeks after implantation. From this time on, the changes above became more evident significantly before most of cavities were repaired by 36 weeks. In contrast to the changes in the SRP group, no expression and synthesis of any kind of collagen could be observed during 12 to 36 weeks after implantation in RP group.Conclusions: Without removal of the bone plate, the SRP fixation not only reduces the degree of plated bone osteoporosis, but also makes the disorganized bone structure restored to normal in terms of the expression and synthesis of type Ⅰ collagen mRNA of osteoblasts lying on the surface of absorption cavities.