BACKGROUND: Gallie, Brooks steel wire, and Halifax vertebral plate clamp are tools for internal fixation of atlas-axis joint. They can keep the flexion-extension stability of atlas-axis joint, but weaken the ability to against lateral bending and rotation. Magerl+Gallie implantation shows good biomechanics stability, but cannot well prevent axial dislocation. OBJECTIVE: To introduce the surgical technique from posterior approach for atlas, and explore the effect on biocompatibility and biomechanics of implants. RETRIEVAL STRATEGY: The articles related to atlas-axis joint dated between January 1970 and June 2007 were retrieved through Pubmed, PML, OVID and Wanfang database using of "atlas, axis, dislocation, fixation, posterior" and "atlas, dislocation, internal fixation, implant, posterior approach, biocompatibility, biomechanics" in Chinese. All collected articles were selected firstly and the articles related to implants, surgical skills, and biomechanics were selected. For articles in identical field, only those published in recently or in authoritative journals were selected. Repetitive articles and Meta analysis were excluded. 127 articles met the criteria and 30 of them were involved. LITERATURE EVALUATION: The articles involved were related to the surgical treatment of dislocation of atlas-axis joint. Of 30 articles, 3 were review articles, 3 were monographs, and the others were clinical or basic researches. DATA SYNTHESIS: ①Lateral mass and pedicle screw implantation techniques can achieve three-dimensional fixation. ②The screw entrance points of atlantoaxial pedicle screw implantation is higher than lateral mass technique, it is unnecessary to expose C1, posterior arch and other deep parts of anatomic structures. C2 nerve root and venous plexus are not separated completely, which reduce injury rate and blood loss. In addition, screw passage of pedicle screw is longer than Harms technique, so screw can completely contact with skeleton to enhance the fixation. CONCLUSION: Atlantoaxial fixation by posterior pedicle screw implantation shows good biomechanics and biocompatibility. It may become the optimal approach for atlantoaxial short segmental fixation.

Objectives: To verify the feasibility and safety of the anterior transpedicular screw(ATPS) fixation of the upper thoracic spine (T1-T4) through the radiological anatomy study on the cadaveric specimens. Methods: The upper thoracic spine thin-section CT data of 40 cases were collected from the radiology de-partment′s database(20 males and 20 females, aged from 18 to 68 years, the mean age was 39.7 years). The data of OPW(outer pedicle width), OPH(outer pedicle height), PAL(pedicle axis length), TPA(transverse section angle), SPA(sagittal section angle), DTIP(distance of transverse intersection point) and DSIP(distance of sagittal intersection point) of each pedicle were measured on the transverse and sagittal sections through the axis of each pedicle. The data were recorded and statistically analyzed. 10 upper thoracic spine(C7-T6) specimens of adults(5 males and 5 females, with unknown ages), with no damage to their appearance, the costovertebral joints and paravertebral soft tissue were completely retained. Then simulate surgical operations were done on the cadaveric specimens based on the obtained data. Screws were implanted anteriorly by free hand. After that, the specimens accepted X-ray fluoroscopy and CT scan. At last, the screws were removed, the speci-mens were sawed along the transaction and sagittal section of the screw channel. Then the success rate of the screw placement was evaluated according to Rao′s worn out classification standard of pedicle screws. Results: From T1 to T4, the OPW decreased from 8.14mm to 3.47mm; the OPH increased from 6.89mm to 10.29mm; the TPA decreased from 32.96° to 11.64°; the DTIP increased from 1.80mm to 5.50mm; the SPA increased from 104.95° to 115.74°; the DSIP increased from 5.95 to 8.76mm; the PAL changed irregularly, from 32.95 to 35.96mm. The pedicle diameters of T3 and T4 were too small to implant ATPS, but the ARTPS can be implanted successfully. The diameter of ATPS was about 4.0mm; the length of ATPS was about 35mm. The diameter of ARTPS was about 5.0mm; the length of ARTPS was about 35mm. 80 pedicle screws were implanted anteriorly, according to Rao′s worn out classification standard of pedicle screws, the fine rate was 90%. The internal walls of 7 pedicles were broken by screws of less than 2mm and no compression to the spinal cord. The internal walls of 5 pedicles were broken of 2 to 4mm, 1 at T1, 1 at T3 and 3 at T4, with varying degrees of spinal cord compression. The internal walls of 2 pedicles were broken of greater than 4mm, 1 at T2 and 1 at T4, with serious spinal cord compression. The external wall of 1 pedicle was broken at T2. Conclusions: The ATPS techniques at T1, T2 and the ARTPS techniques at T3, T4 are feasible, but the safety and clinical practice and further research is needed.

Objective To investigate the procedure of anterior thoracic corpectomy and the surgical outcomes of upper thoracic spine tumors by the right space of the ascending aorta and the right space of the brachiocephalic artery. Methods 12 patients underwent surgery between June 2000 and January 2006. There were 8 cases of primary tumors and 4 metastatic carcinomas, 4 cases of tumor in T3 and 6 cases in T4 and 3 cases in T3,4. The anterior modified transmanubrium approach was made. After the exposure of the tumor through the right space of the ascending aorta and the right space of the brachiocephalic artery, the involved vertebral body and contiguous discs were resected, the spinal cord was decompressed. Curettage was performed in 3 cases for other tumors, en bloc vertebrectomies were performed. As a body replacement, in case of benign disease autogenous bone graft harvested from the dorsal iliac crest was used, and for malignant bone tumors using bone cement. To secure the strut, anterior cervical titanium alloy plates were used until T5. Neurological status was graded according to Frankel grading system. Results 6 cases of bradycardia and hypotension or increasing airway resistance occurred intraoperatively. The mean follow-up period was 28.6 months (range 4-66 months). 3 patients with autogenous bone graft had bone union 6 months postoperatively. According to Frankel grading system, 1 patient improved from grade A preoperation to B postoperation, while another patient from B to C; of the 5 cases with grade C preoperation, 4 patients improved to D postoperation and 1 patient to E; 4 patients improved from D to E; 1 patient with grade E left unchanged. 3 patients died from general metastasis and failure 10-20 months postoperatively. One patient with giant cell tumor recurred 10 months postoperatively. Conclusion Clear exposure and satisfactory outcome can be obtained by the use of the right space of the ascending aorta and the right space of the brachiocephalic artery; it is especially indicated to the upper thoracic spine T3 and T4 tumors, where the spinal compression is located anteriorly.

[Objective]To assess the efficacy of one-stage allograft fusion and anterior spinal stabilization as an alternative treatment of lumbar leaping tuberculosis.[Methods]Eight patients with lumbar leaping tuberculosis underwent anterior route decompression and fusion.Combined chemotherapy was delivered to each patient at least three weeks before operation.There were 5 men and 3 women ranging in age from 21 to 62 years(average,37.2 years).The involved area included L1 and L3 in 2 patient,L1、2and L4 in 3 patient,L2、3and L5 in 1 patient,L2 and L5 in 2 patients.There were 1 patient with Frankel Grade B,2 with Grade C,1 with Grade D and 4 with Grade E.The kyphosis angle ranged from 5?～40?(average 21.5?).The patients were followed up for 12～24 months.[Results]The patients folerated operation well.The operation time were 120～180 min and the bleeding during operation were 400～900 ml.After surgery,pain reliefed in all patients.One patient in Grade B improved to Grade C,1 patient in Grade C improved to Grade D,1 patient in Grade C improved to Grade E,1 patients in Grade D improved to Grade E.The mean angle of kyphosis correction were 5?～20?(average angle:12.5?).There was no postoperative complication.During the follow-up period,all cases healed without any recurrence.There was no breakage of nails or fall of the internal fixation.Spinal fusion occurred after 4～7 months(average 5.3 months) after operation.[Conclusion]Lumbar leaping tuberculosis treated with this surgical technique can achieve a high satisfactory rate with advantages of restoring the spinal stability,providing early fusion,preventing and correcting progression of the kyphosis.

[Objective]To assess the efficacy of autograft fusion and anterior spinal stabilization as an alternative treatment for tuberculosis lesion of the lower cervical spine. [Methods]Thirty patients with tuberculosis of the lower cervical spine underwent anterior decompression and fusion.There were 22 male and 8 female with the age from 24 to 58 years(mean age,37 years).The involved area included 2 vertebral bodies in 21 patients,3 vertebral bodies in 9 patients.Combined chemotherapy was delivered to each patient for at least three weeks preoperatively.There were 5 patients with Frankel Grade B,5 with Grade C,13 with Grade D and 7 with Grade E.The mean kyphosis angle were 12?.[Results]The patiets stood surgery well.The operation time was 70～100 min and the bleeding during operation was 50～150ml.There was no postoperative complication.All patients were followed up for 24～36 months.At the last follow-up visit,5 cases with Frankel Grade B improved to Grade D,3 cases with Grade C improved to Grade D,2 cases with Grade C improved to Grade E,13 cases with Grade D improved to Grade E.There was no breakage of nails or failure of the internal fixation during the follow up.Stable bone union was observed in all cases and the average time required for fusion were 6.5 months.[Conclusion]Anterior debridement and autograft with internal fixation is a safe and effective method for treatment of the lower cervical tuberculosis.

Objective To evaluate the usefulness of imging techniques in diagnosis of corticosteroid-induced avascular necrosis of the femoral head(ANFH).Methods Twenty seven patients with avascular necrosis of the femoral head due to long-term corticosteriod treatment were analysed retrospectively.There were 16 femal and 11 male,ranged in age from 20 to 46 years(mean age 35.6 years).The course of disease was 1～5 years.The administration of corticoid orally was 60～25 mg/d taken on 6 months to 5 years.ANFH was appeared 3 months to 2 years after the administration of corticoid.The imaging examinations included radiography in 20 cases,MRI in 15 cases,both radiography and MRI in 10 cases and CT in 8 cases.8 cases were confirmed by operation and pathology.Results 7 femoral heads in 6 cases with early-ANFH were diagnosed by X-ray,21 femoral heads in 15 cases with early-ANFH were diagnosed by MRI and 11 femoral heads in 7 cases were by CT,19 femoral heads showed a typical “line sign”on MRI.Conclusion The “line sign” on MRI is regarded as the characteristic finding in early-ANFH.MRI is the most sensitive method in the early-diagnosis of the corticosteroid-induced ANFH and it can provide important evidence for clinical management.

Objective To evaluate the short and middle-term outcome of metal surface hemiarthroplasty in treatment of femoral head osteonecrosis. Methods Forty-one patients (forty-eight hips) with average age of 40 years were performed hemi-arthroplasties and followed up for minimum 3 years. Thirty-five cases were at the stage of Ficat Ⅲand 13 at the stage Ⅳ and their acetabular were relatively normal. Measurements of the hip reconstruction were made on the anteroposterior pelvic radiograph assisted with computer. The outcome of metal surface hemi-arthroplasty and the correlation between the orientation of the femoral component and the migration of implant was evaluated. Results The mean duration of follow-up was 5.2 years. The average UCLA hip score was improved significantly (P

[Objective]To provide the mechanical evidence of self manufactured metallic-rectangular frame on the reconstruction of the stability of occipitocervical junction.[Method]Seven of the adult cervical spinal specimens which were entire wet-cadavers(from occipitale to C_6) were made to simulate the C_(0～2) fracture dislocation.These of specimens dislocated were fixed by metallic-rectangular frame and Occipito-cervical plate respectively.The three dimensional movements of C_(0～2) were recorded through photogrametry with a pure moment of 1.53 Nm.The range of motion(ROM) of each specimens in two fixation was caculated.[Result]Loaded by 1.53Nm,In metallic-rectangular frame fixation,the ROM in flexion,extension,lateral bending and axial rotation were 5.9?、7.7?、5.6?、11.2? respectively,decreased by 157.6%、68.8%、58.9%、131.3%,compared with occipitocervical plate fixation group.[Conclusion]Metallic-retangular frame fixation can reconstruct the stability of Occipitocervical junction immediatey,and is a relativity effective internal fixation for occipitocervical fusion.

Objective To investigate the anatomic relationship between the upper thoracic vertebrae and adjacent structures in anterior approach of upper thoracic spine, an anatomy study was conducted and its clinical significance was evaluated. Methods Twenty upper thoracic spine specimens of adult human cadaver were exposed, measured and studied for their anatomic landmarks. The origin, course of the recurrent laryngeal nerve, thoracic duct and blood vessels and their relationship were measured and analyzed. The advantages and disadvantages of different surgical approaches exposing the upper thoracic vertebrae were also evaluated and compared. Results The right recurrent laryngeal nerve reaches the tracheo-esophageal groove at the level of C6-7 disc in 55% of the specimens and derives from vagus nerve at the level of T1,2. The thoracic duct empties into the systemic venous system from T1 to T1-2 disc space in 75% of the specimens and among them, more than 50% up to T1 level. The left brachiocephalic vein is at T3 in 55% of the specimens; and the aortic arch is at T3-4 disc in 80% of the specimens. The anterior aspect of T3 can be easily exposed through a modified anterior approach to the upper thoracic vertebrae in only 45% of the specimens(9), compared with outside space of the brachiocephalic trunk(between the right brachiocephalic vein and the brachiocephalic trunk and left brachiocephalic vein) in 95% of the specimens (19). Conclusion Surgical approach through outside space of the brachiocephalic trunk is simple and adequate to expose the T3,4 vertebra body and can get more exposed space of 0.5-1 of the vertebra body than through inner space of the brachiocephalic trunk and can be utilized selectively during anterior upper thoracic spine surgery. Attention should be paid to avoid injury of vagus nerve in the middle, right recurrent laryngeal nerve on the right and thoracic duct on the left, respectively.

Objective To study the relationship between intraoperative findings during knee joint replacement and clinical manifestations in elderly patients with knee osteoarthritis.Methods A total of 150 cases of senile knee osteoarthritis(182 knee joints) was selected for total knee replacement.Their X-ray examination results were gathered for recording the impairment of the articular surface,the joint space narrowing,and the location and amount of osteophytes.An MRI examination was performed in some of the cases for recording changes of fibrocartilage and locations of meniscus.Results Out of the 150 cases,there were 108 cases of genu varum(mean inversion angle,12.5?;range,0?~25?),21 cases of genu valgum(mean eversion angle,18.3?;range,15?~25?),and 21 cases of flexion contracture (mean angle,15.3?;range,0?~40?).The X-ray findings showed varying degrees of joint space narrowing in all the 150 cases,and osteophytes on the posterior border or at lateral part of the knee joint in 131 cases(152 joints).MRI examinations were performed in 11 cases(15 joints),in which discontinuous,cystoid,and worn-out fibrocartilages were seen.Radial displacement of the meniscus was found.Intraoperative findings proved that the fibrocartilage on the articular surface on the side with joint space narrowing was severely worn away,the collateral ligaments were contracted,the osteophytes were seen at the posterior part of the tibia and the femur,and abrasion or radial displacement of the meniscus on the side with joint space narrowing.Conclusions Joint space narrowing,varus or valgus deformity,osteophytes,and radial displacement of the meniscus are usually found in aged patients with knee osteoarthritis.