BACKGROUND: Biomechanics of bone in vivo is concerned by the scholars who work for orthopaedic and medical bioengineering all the time. The application of strainmeter in this measurement has been studied for many years, but the long-term and successive measuring problems have not been solved. A new installing method for analyzing biomechanics of bone in vivoshould be considered to be explored. OBJECTIVE: To investigate the biochemical change of external fixator at both external and internal medullary cavity of anxial compressing fracture end invivo when external fixator is used DESIGN: Randomized and controlled animal experiment SETTING: Laboratory of Orthopaedic Department, Renmin Hospital, Wuhan University MATERIALS: Totally 18 healthy white rabbits, of rather gender, with the body mass of 3.6 to 4.2 kg , were chosen. METHODS: This experiment was conducted at the laboratory of Or thopaedic Department, Renmin Hospital, Wuhan University in November 2004. The chosen 18 healthy white rabbits were randomly divided into 2groups. External measuring group (Group A): the strain guage was affixed to the tibia external cortex by 502 gauge. Internal measuring group (Group B): strain guage coated with bone cement was installed on the tibia internal cortex. Group A and Group B were divided into two subgroups A1, A2 and B1, B2, respectively according to the pressure 0.5 time body mass and 1 time body mass. Strain voltage change and attenuation coefficient after compressing were measured with scaler. Statistical comparison was performed among the groups. MAIN OUTCOME MEASURES: ① The data of scaler curve. ② Attenuation coefficient of different compressions.RESULTS: ① The scaler curves of Group A changed greatly during early stage. After reaching stable stage, trendline of internal and external cortex went consistent but the former value was higher than that of the latter . The time of compression reaching stable was shorter in the Group B than in the Group A, and the absolute value of strain was smaller in the Group B than in the Group A. ② Before reaching stable after compression, the attenuation coefficient was low in the Group A1 as compared with Group A2. There was the same result between Group B1 and Group B2 group. When comparison was conducted between Group A and Group B, the curve of Group A decreased firstly, then ascended, but there was no ascending tendency in the Group B. After reaching stable, there were descending tendency in the Group A1 group and Group A2. It descended fast in the Group A2, while it kept at normal level in the Group B1 group. Fluctuation appeared in the Group A2. CONCLUSION: Strain of external medullary cavity is significantly larger than that of internal medullary cavity. It is easier to reach stable in the inter nal medullary cavity than in the external medullary cavity. 0.5 time of body mass is suitable at the initial period in treating fracture with external fixator.

BACKGROUND:The region around the hip is a bone tumor predilection site. It is difficult to conduct tumor resection due to the involvement of weight loading area. Tumor resection requires high surgical technique. The pelvis and hip are often needed to be rebuilt.
OBJECTIVE:To compare the effects of three reconstruction methods after tumor resection around the hip.
METHODS:From January 2007 to December 2012, 20 patients with bone tumors around the hip were treated by surgery in the Zhongshan Hospital, Wuhan University, including 7 benign tumors, 13 borderline and malignant tumors. Eight patients received al ograft. Eight patients received arthroplasty. Four patients received saddle prosthesis.
RESULTS AND CONCLUSION:A total of 20 patients were fol owed up for 5 to 60 months (averagely 40 months). According to Enneking evaluation criterion, the operative outcome was evaluated as excellent in 8 cases, good in 5 cases, average in 4 cases, and poor in 3 cases. Excellent and good rate was 65%. Results suggested that after excision of bone tumors, al ograft, arthroplasty or saddle prosthesis can significantly elevate patient’s survival rate, improve patient’s living quality and is an effective therapy for treating tumors around the hip.

Objective To probe the proper management of dural tear sustained during operation on the lumbar spine and cerebrospinal fluid leakage. Methods Sixty-eight patients sustained dural tears, which were repaired during the operation. According to the type of the dural tear, different ways was used to treat the cerebrospinal fluid leakage.Results Fifteen patients of the sixty-eight had cerebrospinal fluid leakage. None have any longterm deleterious effects. Conclusions Repair the dura during the operation was the best way to treat the dural tears, and closed subarachnoid drainage can successfully treat the cerebrospinal fluid leakage.

Objective To investigate therapeutic effects of muscle sliding operation treating Volkmann ischemic contracture of the forearm. Methods 32 cases Volkmann ischemic contracture were classified two types: the single type and the complex type. Three approaches were employed to treat different types which were single muscle sliding operation, muscle sliding plus skeletal operation, muscle sliding operation plus neurolysis.Results 29 cases were followed up, which excellent and good was 93.7 percent.Conclusions Muscle sliding operation was effective management for Volkmann ischemic contracture, and the skeletal operation or neurolysis could managed for the complex type in the meantime.

BACKGROUND: Many scholars adopt allograft interbody fusion for vertebral body resection and reconstruction, bone fusion time is better than autologous bone graft's, and its integration provides an early support and stabilizing, but the preparation of allogeneic bone graft material is easy to destroy b0ne-inducing factor in matrix, which is not conducive to bone growth. OBJECTIVE: To innovatively design and verify the ability of reconstructing rabbit cervical vertebrae with the compound of humeral cortical ring allograft (HCA) packed with red bone marrow (RBM) and autogenous cancellous bone (ACB). DESIGN, TIME AND SETTING: Randomized controlled animal experiment was performed at the laboratory of Orthopedic Department in Renmin Hospital of Wuhan University, between October 2004 and March 2006. MATERIALS: Sixty healthy adult New Zealand white rabbits, of either sex, body mass of 2.0-2.5 kg, were involved in this study. Twelve rabbits were used for HCA preparation, while the remaining 48 rabbits were randomly divided into 3 groups with sixteen rats in each group. Autologous RBM was extracted from the anterior superior lilac spine through puncture; ACB was obtained from td-cortical bone of rabbit iliac crest. Autologous RBM and ACB were compounded and filled in the self-made HCA. METHODS: Models of the fourth cervical vertebrae defect were created by surgery to simulate tumor resection in New Zealand white rabbits, which were divided into 3 groups randomly. Combined transplant group was treated with the compound of RBM+ACB+HCA; autologous bone transplant group with autogenous lilac crest; HCA transplant group with HCA. MAIN OUTCOME MEASURES: Vertebral reconstructions were evaluated by X-ray, histopathological observation and scanning electron microscope, as well as measurement of serum alkaline phosphates at different periods postoperatively. RESULTS: Eight weeks post-surgery, graft materials fused with the upper and lower cervical fusion, a large number of bone callus were observed in combined transplant group and autologous bone transplant group; HCA transplant group was present with a small amount of callus growth and poor fusion. Serum alkaline phosphatase levels were elevated in all groups, significantly higher in combined transplant group and autologous bone transplant group compared with HCA transplant group (P < 0.01 ). There were no significant differences of serum alkaline phosphatase levels between combined transplant group and autologous bone transplant group at 4 weeks or among 3 groups 8 weeks (P > 0.05). Histological analysis exhibited numerous mature bone matrix, bone trabecula and bone marrow cavity formed in combined transplant group and autologous bone transplant group. Scanning electron microscopy showed that many new bone formations in combined transplant group and autologous bone transplant group.CONCLUSION: The compound of RBM+ACB+HCA and autogenous lilac crest transplantation can efficiently reconstruct cervical vertebrae, RBM+ACB can improve the reconstruction efficiency of HCA, and could use as a matedal in cervical reconstruction.

BACKGROUND: The clinical application of one-level osteotomy and multilevel osteotomy has been well documented, but currently few studies were reported to compare their biomechanical characteristics.OBJECTIVE: To investigate the biomechanical characteristics of one-level osteotomy with Dick screw fixation and multilevel osteotomy with Luque instrumentation in the treatment of kyphosis.DESIGN: Randomized comparative experiment.SETTING: Laboratory of the Department of Orthopedics, Renmin Hospital of Wuhan University.MATERIALS: Fresh specimens of thoracic and lumbar spinal segments obtained from 12 3 or 4-year-old calves.METHODS: The experiment was conducted in the laboratory of the Department of Orthopedics, Renmin Hospital of Wuhan University between September 2002 and September 2003. Fresh spinal segments T8-L5 from 12 calves were randomized into an intact group, Dick screw group with one-level osteotomy with Dick screw fixation and Luque group with multilevel osteotomy with Luque instrumentation, with 4 spesimens in each group. Lateral bending test of the specimens was performed to examine the physiological overload using an Instron 5 500 universal material testing machine at the constant speed of 10 mm/minute until fracture or dislocation was induced. Changes in the loading were recorded and the induced injuries observed to obtain the load-displacement curve of the injury test.MAIN OUTCOME MEASURES: The load-displacement curve of the destructive right bending test in each group.RESULTS:All the data of 12 canines were involved in the result analysis.The spinal segments of the intact group yielded to the force of 3 600 N with a flat and smooth load-displacement curve, and those of Dick screw group yielded to a load of 2 800 N with also a relatively flat curve, while in Luque group, the segments did not yield until a load of 7 160 N, followed by drastic decrease of the resistance to less than 4 000 N, generating a flat and smooth curve afterwards.CONCLUSION: Luque instrumentation is a little more preferable than Dick screw in terms of the maximum resistance, but this difference does not justify the clinical decision of their superiority. Both techniques benefit postoperative recovery of spinal function with strong stability.

BACKGROUND: Vertebral reconstruction is stil a chal enge for spinal surgeons. Ideal reconstruction materials should have good osteogenesis ability, reliable support performance, low price and simple operating steps.
OBJECTIVE:To investigate the effect and feasibility of al ogenic cortical ring packed with autogenous cancellous bone in the reconstruction of rabbit cervical vertebra defect.
METHODS:Cervical vertebra defect models were established by resection of the fourth cervical vertebra in rabbits. Frozen-dried humeral cortical ring of rabbits was made to prepare the al ogenic cortical ring which was packed with autogenous cancellous bone. Then, al ogenic cortical ring packed with autogenous cancellous bone, single al ogenic cortical ring and autogenous iliac bone were used to repair rabbit cervical vertebra defects.
RESULTS AND CONCLUSION:The X-ray, histopathological examination, and scanning electron microscope examinations al showed that the bone union was most significant in group reconstructed with al ogenic cortical ring packed with autogenous cancellous bone. The alkaline phosphates activity in serum was higher in groups reconstructed with al ogenic cortical ring packed with autogenous cancellous bone and with autogenous iliac bone than in group reconstructed with only al ogenic cortical ring at 2 and 4 weeks after operation (P<0.01), but there was no difference between the former two groups. The biomechanical examination showed that the stability of al ogenic cortical ring packed with autogenous cancellous bone was higher than that of autogenous iliac bone at 1 month after operation (P<0.01). These findings indicate that the effect of al ogenic cortical ring packed with autogenous cancellous bone in the reconstruction of rabbit cervical vertebra defects is satisfactory, with a good biocompatibility, which is a promising method for the reconstruction of vertebral defects.

BACKGROUND:The effects of both conservative and traditional open reduction and internal fixation are dissatisfactory in the treatment of thoracolumbar fractures, however, minimal-invasive percutaneous pedicle screw-rod systems provide a new available method.
OBJECTIVE:To investigate the clinical effect of percutaneous pedicle screw fixation using Sextant minimal-invasive 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 open pedicle screw fixation (30 patients) for single-level vertebral body compression fractures in Department of Orthopedics, Renmin Hospital of Wuhan University from February 2011 to January 2013, were enrol ed in this study. They showed no neurological signs and symptoms. The operative time, intraoperablood loss, postoperative drainage amount, length of hospital stay, pre-and post-operative Cobb angle and anterior vertebral body height ratio were recorded and compared between two groups.
RESULTS AND CONCLUSION:Except two patients in open pedicle screw fixation group were lost after discharge, al other patients were fol owed up for 8-14 months. There were significant differences in operative time, intraoperative blood loss, postoperative drainage amount and length of hospital stay between two groups (P=0.000 0). The post-operative Cobb angle was significantly lower while anterior vertebral body height ratio was significantly higher at one week than those before fixation in two groups (P=0.000 0). No significant difference was found in correction loss between two groups at 8 months after operation. Experimental findings indicate that, percutaneous pedicle screw fixation using Sextant system has a satisfactory outcome in the treatment of thoracolumbar fractures. However, understanding the correct indications is very important for clinical application.

Objective To investigate the role of fibroblasts in nonunion fracture healing using extracorporeal shock wave(ESW) treatment. Methods Thirty healthy rabbits were selected to make the models of non-union fractures of the right tibias, which were then held apart by external fixation. 12 weeks after the operation, hypertrophic non-unions were confirmed in 27 of the rabbits by radiography. These 27 were divided randomly into a treatment group and a control group. The test animals were treated with ESW under general anaesthesia. The two ends of the nonunion fracture were shocked 1 000 times at 0.54 mJ/mm2 and a frequency of 60 times/minute. The nonunions of the control group were treated with external fixations only. Histological examination and transmission electron microscopy(TEM) were conducted after 2 and 6 weeks. Standardized radiographs were taken after 12 weeks of the shock wave treatment. Results ESW induced microfractures, which initiated the healing process of the nonunionfractures. X-rays showed that 8 of the 9 fractures of the treatment group had healed after 12 weeks of EWS treatment, but only 3 of the 9 in the control group had healed. Statistical analysis showed that this difference was significant at the 5% level. After 2 weeks of ESW treatment, TEM showed many collagen fibers around the fibroblasts in the treatment group, with characteristic and periodic transverse lines. This indicated that the fibroblasts had been secreting collagen fibers as osteoblasts. Six weeks later, osteoblasts and fibroblasts had formed bone lacunes, and they had become osteocytes. However osteogenetic activates were not found in the control group. Conclusions Fibroblasts are activated by ESW to better form bone tissue. This process plays an important role in rebuilding broken bones.

BACKGROUND:Currently, one of common methods is discectomy, nerve root decompression and fusion rigid fixation from the midline approach for disc herniation which is inefficient by conservative treatments. Thus, it is causing degeneration and limiting lumbar physiological activity of adjacent segments. The treatment of non-fusion lumbar disc herniation with the traditional posterior midline incision approach has some disadvantages such as big incision, wide peeling, and back muscle denervation.
OBJECTIVE:To observe therapeutic effects of dynamic stabilization system through Wiltse approach on lumbar disc herniation, and to compare the outcomes with traditional posterior approach.
METHODA total of 46 patients, who had undergone discectomy and internal fixation using dynamic stabilization systems for lumbar disc herniation at the Renmin Hospital of Wuhan University from January 2011 to January 2013, were enrol ed in this study. The operation was performed through the traditional posterior approach in 25 patients and Wiltse approach in 21 patients.
RESULTS AND CONCLUSION:Al 46 patients were fol owed up for 7 to 31 months (averagely, 13.8±2.4 months). The length of incision, intraoperative blood loss, and postoperative drainage amount were less in the Wiltse approach group than in the traditional posterior approach group (P<0.05). No significant difference in visual analog scale scores and operative time was detected between the two groups at 1 week and 6 months after fixation (P>0.05). Radiographs revealed that the position of implants was good in al patients, no loosing or breakage. These data verified that the early effect of dynamic stabilization system through Wiltse approach for lumbar disc herniation is similar to that of traditional posterior approach.