For orthopaedic care of patients to continue to improve, new approaches, especially minimally invasive spinal technique, must be continually developed.To verify this technique actually provides improved outcomes, these approachs must be subjected to rigorous scientific study. However, because outcomes of clinical interventions only can be studied in human subjects, this practice must not only meet scientific criteria. it also must meet strict ethical criteria. The author analysised the state of minimally invasive spinal technique in china and foreign countries, and illustrated ethical problems and countermeasure on playing of minimally invasive technique into spinal practice.

The author analysised the state of playing of human cadaver specimens in orthopedic biomechanical study in china and illustrated ethical problems an countermeasure on this issue.

Objective To study the methods of repairing the sole defects and reconstruction of the sensory function. Methods Twenty- nine cases of sole defect were repaired with flaps and full- thickness grafting according to the weight- bearing area and non- weight- bearing area. Sixteen cases had reconstruction of the sensory nerves. Results Twenty- nine cases were followed up for 1－ 9 years. One case failed. One case required thinning the flap. Twenty- eight cases have gained normal weight bearing ambulation. Ulcer occurred in one case, giving an ulcer rate of 3.4％ . The sensation have recovered to S2－ S3 in 16 cases repaired with reconstruction of cutaneous sensory nerves. Thirteen cases repaired with non- innervated flaps and full- thickness grafting showed deep pain sensation, and over the 1－ 2 cm area coverage around the flaps there was light touch sensation. No significant difference was found in the ulcer rate between reinnervated and non- innervated flaps. Conclusion Defects of the weight- bearing area in sole must be repaired with flaps. The medial foot island flap, medial pedal island flap, toe arterial flap and anterolateral thigh flap are the appropriate options. Defects of the non- weight- bearing area could be repaired with full- thickness grafting. The transplantation of non- sensory skin flaps can re- establish the sensory function, so the reconstruction of sensory nerve is of minor importance.

Objective To explore a new method in the treatment of odontoid pr ocess fracture with a self-designed screw and anterior percutaneous odontoid fix ation. Methods Computerized tomography (CT) was used to measure the coronal and sagittal external diameter of the base of odontoid process, the length of the od ontoid process, the total height of the axis and the angle between the axial lin e of the odontoid process and the vertical line of the anterosuperior border of the C3 vertebral body in 40 normal adults aged from 20 to 45 years. Ten odontoid process fractures were fixed with cannulated anterior odontoid screws and monit ored under fluoroscope. According to Anderson's classfication, there were 4 of t ype Ⅱand 6 of type Ⅲ. 4 had no any displacement of the dens, 3 had displacemen t less than 5 mm, and 3 had displacement of 5 mm or more. The fractures were fre sh in 8, and the other 2 were old. Each fracture was fixed by one screw, and ant erior bone-graft was performed in old fracture after screw fixation. Results The coronal external diameter of the base of odontoid process was (8.8?1.2) mm, wh ile the sagittal external diameter was (10.9?1.0) mm, the length of the odontoi d process was (14.2?1.2) mm, the total height of the axis was (38.2?1.8) mm an d the angle between the axial line of the odontoid process and the vertical line of the anterosuperior border of the C3 vertebral body was 23.1??1.4?. Satis factory results were achieved in all patients, and all screws were in good posit ion. No neurological deterioration occurred. After a mean follow-up of 19 months (range, 10 to 25 months), 8 cases showed radiographic union, while 2 nonunion. Neither clinical symptoms nor screw loosening or breakage occurred. Conclusion The direct anterior percutaneous screw fixation is practical for fractures of t he dens with appropriate instrumentation, as long as the surgeon is familiar wit h the topographic anatomy and makes sure the insertion point, the depth and the angle on percutaneous insertion of the screws, the satisfactory outcome will be obtained. There is no stiffening of the C1,2 and the motion limitation. The ant erior percutaneous procedure is surgically less traumatic than the conventional cervical approaches. One screw is optimal for this procedure.

Objective To compare the influence of the dynamic device(DD) of pedicle screw fixation and its equivalent rigid device (RD) on bone mineral density and bone structure of the vertebrae. Methods 24 goats were randomly divided into 4 groups: control group, single posterolateral fusion group, dynamic device with posterolateral fusion group and rigid device with posterolateral fusion group. After 24 weeks postoperative observation, the animals were sacrificed and the fixed lumbar spines were harvested. The bone mineral density (BMD) of these harvested specimens was measured by quantitative computed tomography (QCT). Then the L3 segment was embedded in methyl methacrylate and sectioned after alcoholic dehydration. Undecalcified slides (50 ?m in thickness) were stained with toluidine blue. Quantitative histologic analysis was performed in a semiautomatic way. The static parameters consisted of trabecular bone volume (TBV), the mean trabecular plate thickness (MTPT) and mean trabecular spacing (Tb.Sp). The main dynamic histomorphometric parameter, bone mineralization rate (MAR), was calculated by measuring the mean distance between two flurochrome labelings. Results The BMD in the rigid device group decreased significantly compared with control group (P

Objective 7 cases of thoracic spinal cord injury without radiographic abnormality (SCIWORA) were analyzed to elevate the level of diagnosis and treatment.Methods The type of spinal cord injury were classified into complete injury in 2 and incomplete injury in 5 according to Frankel. 5 cases had MRI examination. Conservative therapy was adopted in 5, and operation was programmed in 2.Results 4 cases recovered completely , 2 cases recovered partly , and 1 case had no recovery.Conclusion MRI provides reliable foundation for diagnosis and treatment to thoracic SCIWORA. The result is satisfactory in those incomplete injury.

Objective To discuss the functional results of percutaneons compressive screw fixation for float injury to the pubic symphysis. Methods From March 2003 to March 2007, 48 cases of float injury to the pubic symphysis were treated with percutaneons compressive screws, including 27 males and 21 females with an average age of 29.4 years. Of them, 39 eases were complicated with injury to the pelvic posterior ring. Emergency surgery was done for 13 cases, 27 cases were operated on within 3 to 7 days after injury and 8 within 7 to 14 days. Guided pins and screws were used during dosed reduction and percutaneous pelvic fixation was done under the guidance of intraoperative fluoroscopic imaging. Float injury to the pubic symphysis was amended by percutaneous fixation after dosed manipulation. Results The average operation time for the48 patients was 55 (31 to 100) min. The intraoperative bleeding averaged 20 to 30 mL. Satisfactory reduetian and fixation was achieved in 41 cases, but 7 cases had poor reduction. All the fractures healed 3 to 6 months postoperatively without infection, nonunion or injury to vessels, nerves or organs. All the patients could turn the body freely in bed the day after operation. Those without injury to the pelvic posterior ring could walk with crutches 3 days after operation. By the Orlando evaluation system for pelvic fractures, 37 eases were rated as excellent, 7 as good, 3 as fair and I as poor. Conclusions The percutaneous compressive screw fixation may decompress the pelvic hematoma, allowing early definitive fixation without the risk of additional hemorrhage. Complications associated with open posterior pelvic surgical procedures may be avoided by using percutaneons techniques.

Objective To study the therapeutic efficacy of the chondroplasty with radiofrequency technique under arthroscope for osteoarthritic knees in the senile patients.Methods Thirty-six patients were divided randomly into control and test groups(in each with 18 patients).The patients suffered from osteoarthritis of knees.The control group confirmed and treated by knee arthroscope,which was subjected to debridement with routine technique.The test group was treated by chondroplasty with radiofrequency technique under arthroscope.Results The patients developed no infection or other complications.Better therapeutic results were obtained after follow up of 6 to 18 months.Conclusions Chondroplasty with radiofrequency technique under arthroscope for the osteoarthritic knees has the advantages of less injury,less bleeding,less complication and quick recovery.

Objective To develop a three-dimensional finite element model of atlantoaxial instability and compare the biomechanical properties of percutaneous anterior transarticular screw (ATS) and posterior transarticular screw (PTS) fixations.Methods A pathologic three-dimensional finite element model of atlantoaxial instability was developed from CT images of the upper cervical spine of volunteers with the aid of softwares,such as Mimics,Freeform,and Ansys.Percutaneous C1-2 ATS and PTS fixation modes were simulated and implanted to the model.Under the preload of 40 N and force moment of 1.5 Nm in anterior flexion,posterior extension,lateral bending,and axial rotation,biomechanical properties of the two fixation modes were compared.Results Under the four loading modalities,both fixation techniques provided maximal inhibition on C1-2 movement.The maximal stress for ATS was larger than that for PTS and maximal displacement for ATS was smaller than that for PTS.Conclusions Both ATS and PTS provide similar outlook and are effective to stabilize the atlantoaxial joint.Biomechanical performance of percutaneous C1-2 ATS is better than that of percutaneous C1-2 PTS.

Objective To study the feasibility and clinical effect of percutaneous C2 pedicle lag screw in treatment of Hangman's fracture and define the indications of the technique. Methods There were 9 patients including 5 males and 4 females at average age of 36 years (26-68 years). According to a Levine and Edwards System, there were 5 patients with type Ⅰ hangman' s fracture, 3 with type Ⅱ hangman' s fracture and 1 with type Ⅱ A hangman' s fracture. According to American spinal injury association (ASIA) system, the spinal cord function was ranked at Type D in 2 patients and Type E in 7. All patients achieved anatomic reduction by skull traction. Under general anesthesia, 9 patients were fixed with percutaneons C2 pedicle lag screw. The whole procedure was done under monitoring of "C"-arm fluoroscopy for safety and accuracy. Results All patients obtained bony fusion within 2-3 months, with no infection, neurological deficits, vertebra artery injury or other complications. CondusionsThe percutaneous C2 pedicle lag screw fixation is minimally invasive and effective for treatment of Hangman's fracture. During the course of treatment, the function of upper cervical spine remains unaffected.