External fixators have been widely u sed in treatment of war trauma due to t heir small size,light weight,easy application,and convenience in transport.There are several types of military external fixato r,such as FESSA(Fixateur Externe du Service de Sant?des Arm?es),CMC(Croatian Medical Corps),Synthes and Hoffman-Ⅱ.All of these have been used on the battlefields of Rwandese War,Croatia Wa r and the first Persian Gulf War.Most of military external fixators are unilateral connectable-joint.For temp orary fixation,one bar is enough;by adding another parallel bar,the fixation can be use d for long-time fixing.Facing with a great demand of war trauma treatment ,we should develop new types of military external fixator with more simplicity and less size or weight. [

Atlantoaxial dislocation with high spinal cord compression is a common disease, which endangers people's health and is difficult to treat. Transoropharyngeal surgery is a very important method for the treatment of this disease. The author briefly reviews various operations of decompression and internal fixation through anterior transoropharyngeal approach and some correlative treatments conducted over the past few years. Although transoropharyngeal surgery has not been widely adopted at present, with increasing understanding of physiology and anatomy of the cranio-cervical junction, and development of microsurgical technic, and improvement in pre-vention and treatment of amplications, it has rapidly become a more acceptable approach for the treatment of atlantoaxial dislocation with cord compression. And with the application of new techniques, its treatment result will be conspicuously improved.

Objective To prepare recombinant human bone morphogenetic protein-2(rhBMP-2)loaded chitosan nanospheres and to evaluate their ectopic bone formation activity in vivo. Methods The rhBMP-2 loaded chitosan nanospheres were prepaid using the ionic crosslinking method with TPP as a crosslinking agent.The morphological properties and particle size distribution were evaluated by transmission electron microcopy(TEM) and particle size analyzer.An intramuscular ectopic bone formation test was carried out to compare the ectopic bone formation activity in 24 SD rabbits that were randomized into 4 even groups.rhBMP-2 loaded chitosan nanospheres (1 mg),rhBMP-2 (1 mg),chitosan nanospheres and nothing were implanted into the muscle pouch at the left thigh,respectively,in groups A,B,C and D. Results The rhBMP-2 loaded chitosan nanospheres were well distributed and spherical in shape.The average particle diameter was 230.0 nm,the entrapment efficiency was 66.87％ ± 4.58％,and the loading rate was 33.44 ± 2.29 μg/mg.The mean ALP activity was respectively 1.94 ± 0.35 kat/g,1.48 ± 0.56 kat/g,0.20 ±0.07 kat/g and 0.18 ±0.06 kat/g in groups A,B,C and D,with a significant difference between the 4 groups( F =42.959,P =0.000).The mean Ca2 + content was respectively 5.20 ± 1.42 μg/mg,3.80 ± 1.40 μg/mg,0.19 ± 0.08 μg/mgand 0.20 ± 0.08 μg/mg in groups A,B,C and D,with a significant difference between the 4 groups ( F =39.242,P =0.000).Groups A and B were obviously higher than groups C and D and group A was obviously higher than group B in terms of ALP activity and Ca2+ content. Conclusion The rhBMP-2 loaded chitosan nanospheres prepared by ionic crosslinking method show a good property and obvious ectopic bone formation activity.

BACKGROUND:Many studies have shown that different nanostructures produce different influences on cellbioactivity, but the nanonetwork structure is not reported yet. OBJECTIVE:To study the influence of the nanonetwork topography on the bioactivity of bone marrow mesenchymal stem cels. METHODS:The nanonetwork topography was fabricated on biomedical titanium surface by alkali-heat treatment, and pure titanium served as control group. Bone marrow mesenchymal stem cels were co-cultured with the above two types of samples. cellmorphology and cytoskeleton were observed using scanning electron microscope and immunofluorescence method. The celladhesion, proliferation and osteogenic differentiation were detected by measurement of absorbance values at different culture time. RESULTS AND CONCLUSION: The nanonetwork topography had significant advantage on the number of adherent cels at 30, 60 and 120 minutes of co-culture. The cellproliferation was significantly accelerated by the nanonetwork topography at days 1, 3, 5 of co-culture, and the absorbance values in the nanonetwork group were significantly higher than those in the pure titanium group (P < 0.05). The alkaline phosphatase activity in the nanonetwork group was also significantly higher than that in the pure titanium group at 14 days of osteogenic induction (P < 0.05). The cellshape and cytoskeleton on the nanonetwork surface were better than those on the titanium surface. These findings indicate that the nanonetwork topography has better effects on cellbioactivity compared with pure titanium.

Objective To study the feasibility and clinical results of C2, 3 pedicle-lateral mass plate fixation in the treatment of unstable Hangman's fractures. Methods From March 1999 to July 2005, 25 cases of unstable Hangman's fracture were treated surgically using the C2, 3 pedicle-lateral mass plate. All the cases were followed up for the healing of bone and function of the cervical vertebrate. Results The average follow-up period was 38 months. Twenty-three cases had a perfect reduction. Three cases had kyphosis deformity. There were no other complications related to the operation. AH the cases had a perfect early fusion of the C2 pedicle isthmus and long-term stability of C2, 3 intervertebral space. The clinic results were good. Conclusion Since the C2, 3 pedicle-lateral mass fixation can provide immediate reduction and satisfactory biomechanical stability, it is a good device for unstable Hangman s fractures.

Objective To evaluate the clinical effect and application value of internal fixation of Magerl combined with Brooks technique for atlantoaxial instability. Methods A total of 18 patients with atlantoaxial instability, reducible atlantoaxial dislocation with reduction after traction and irreducible atlantoaxial dislocation with traction reduction after anterior laxation were treated with internal fixation of Magerl combined with Brooks technique using autologous bone grafts. Results The patients were followed up for an average 18 months (6-36 months). Screw was probably cut into the vertebral artery in one case. The guide needle was cut into the pharynx due to incorrectly penetrating the C 1 anterior arch of atlas for 3.5 cm in one case but no early complications such as spinal cord injury and local infection occurred. The spinal cord function improvement was marked in 3 cases, good in 9, mild in 4 but unchanged in 2. No case got worse. There were no loosening or break of the screw and cable. Conclusions Combined fixation of Magerl and Brooks techniques reaches three-point fixation and improves the reduction effect. It is necessary to use the combined fixation with best biomechanical stability for atlantoaxial dislocation patient with reduction or near reduction if the structure of the posterior arch of C 1,2 is intact.

To summarize the clinical results of combined transoral anterior decompression and posterior decompression and internal fixation of irreducible atlantoaxial dislocation with spinal cord compression. 12 cases of irreducible atlantoaxial dislocation with spinal cord compression were operated on with transoral anterior decompression combined with posterior decompression and occipitocervical internal fixation with occipitocervical CD rod or Cervifix. With an average of 20 month follow up, clinical cure rate was evaluated according to Symon and Lavender . Vertebral canal vector diameters in MR were measured. The results showed that the total clinical effective rate was 91.6%, and the remarkable effective rate was 50%. The average improvement rate of vertebral canal decompression was 73.6 %. These results suggest that transoral anterior decompression combined with posterior decompression and internal fixation is more suitable for irreducible atlantoaxial dislocation with spinal cord compression.

From July 1998 to May 2000, 31 cases of lumbar spondylolisthesis accompanied with lumbar stenosis were treated with spinal cord decompression, autograft interbody fusion and fixed by Dyna lok system. All the patients were followed up for 6 to 28 months, averaged 12 7 months. 29 of the 31 patients were recovered completely. 2 cases of cauda equina were recovered within 2 months. Lowback pain remained in 1 case of multi segements spondylolisthesis which had been fixed for 3 vertebrae. 1 patient accompanied with cervical spinal stenosis had some residual claudication. In conclusion, spondylolisthesis fixed with the Dyna lok system can achieve a satisfactory result.

Objective To study the repair of great vessels injured by firearm in extremities. Methods From May 2002 to Sep. 2005, 15 cryopreserved homologous arteries were transplanted to repair the defects of great vessels of extremities in 14 patients, including 5 cases of defect of brachial arteries, 1 case of defect of axillary artery, 1 case of popliteal artery damage and 7 cases of defect of femoral arteries. The average length of homologous arterial transplants was 9.5 cm. After operation, all the 14 patients were monitored and treated according to principles of microsurgery. Result No early reject reaction was found in all the 14 cases, and all the wounds healed after Ⅱ stage treatment. With Doppler ultrasonic examination 2-3 weeks after healing, it was proved that 100% of the vessels were patent. In 4 to 8 month follow up, the function of the extremities recovered well, and no delayed reject reaction was observed. Conclusion The vessels after cryopreservation is a suitable biomaterial in homologous transplantation for repairing the defect of great vessels of the extremities as a result of firearm injury.

[Objective]To investigate the method of anterior transsternal approach for the patients with upper thoracic spine diseases and the clinic results.[Method]Six cases upper thoracic spinal diseases,1 case of C7/T1 grade V dislocation,1 case of T1、2 TB,2 cases of upper thoracic tumor,1 case of T2 fracture and 1 case of T2、3 disc prolapse,were treated with the anterior transsternal approach operation since Oct.2001.The lesions areas were exposed via partial or complete sternotomy.The relative articles were reviewed.[Result]The average follow-up was 12.4 months(range from 6 to 22 months,except the died one).The case of C7/T1 grade V dislocation died of respiratory tract obstruction and one case of malignant schwannoma recurred 6 months post-operation.Good results were obtained in the other 4 cases.No operative complication happened in all cases.[Conclusion]While the transthoracic lateral approach cannot expose the upper thoracic spine clearly,the anterior cervical approach cannot expose the T2、3 clearly also.The anterior transsternal approach can provide a safe access to the lesions located on the upper thoracic spine above T4.