Objective To systematically evaluate the efficacy and safety of posterior short segment and long segment pedicle screw internal fixation in the treatment of thoracolumbar burst fracture. Methods By searching the database, including PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, a comprehensive study was carried out to make a comparison between the posterior short segment and the long segment pedicle screws internal fixation in treatment of thoracolumbar burst fracture, and Meta analysis was performed. Results A total of 14 related studies and 658 patients were enrolled in the study, including 320 patients in short segment group and 338 cases in long segment group, and Meta analysis was performed. The results suggested that there was no significant difference between the short segment group and the long segment group in terms of the deformity angle of the injured vertebra measured after operation and at the last follow?up, and sagittal index at the last follow?up ( MD=-0. 22,95%CI -2. 73,2. 28,P=0. 86;MD=-0. 28,95%CI -2. 23,1. 67, P=0. 78;MD=0. 47, 95%CI -3. 45, 4. 39, P=0. 81 ) . Besides, both groups had no statistical difference in post?operative COBB angle,anterior vertebral height and compression rate of injured vertebrae ( MD=0. 21,95%CI -0. 65,1. 06,P=0. 64; MD=-0. 46,95%CI -1. 40,0. 49,P=0. 34; MD=0. 47,95%CI -2. 28, 3. 21, P= 0. 74 ) , while the differences in COBB angle, anterior vertebral height, compression rate, correction loss were statistically significant at the last follow?up (MD=5. 11,95%CI 2. 81,7. 40,P<0. 0001;MD=-11. 89,95%CI-15. 28,-8. 50,P<0. 00001;MD=6. 46,95%CI 3. 85,9. 07,P<0. 00001) . There was no significant difference in VAS scores and the ODI scores between the two groups at the last follow?up ( MD =0. 01,95%CI -0. 15,0. 17,P=0. 9; MD=-0. 47,95%CI -2. 68,1. 74,P=0. 86),while the two groups showed statistically significant difference in fixation failure ( RR = 0. 08, 95%CI 0. 01, 0. 15, P = 0. 02 ) . Conclusion Posterior long segment pedicle screw internal fixation is more effective in treating thoracolumbar burst fracture than short segment surgery. It can reduce the COBB angle,restore the anterior height of the injured vertebra,and decrease the anterior vertebral pressure.

Objective:To investigate the diagnosis and prognosis of one patient with carcinoma ex pleomorphic adenoma (CXPA)composed of three malignant components in parotid gland,and to raise the clinicians'awareness of the disease.Methods:A patient was presented to hospital because of the mass in left parotid gland region for more than 30 years and the accompanied pain lasted for one month.After color ultrasonography,the left parotid gland tumor resection was performed. Results: The operation was successful. The postoperative pathological diagnosis results comfirmed as CXPA,it was composed of three malignant components,including non-specific adenocarcinoma,ductal carcinoma,and myoepithelial carcinoma.Conclusion:CXPA composed of three malignant components at the same time are extremely rare.CXPA is difficult to diagnose and its prognosis is poor.The clinicians are supposed to improve the understanding of CXPA.

Objective:To investigate the method of arthroplasty for reconstructing femporomandibular joint (TMJ) after the establishment of TMJ articular defect models in the rabbits,and to clarify the replacement and repair effects of carboh fiber reinforced polyetheretherketone (CFR-PEEK) material TMJ prostheses,and to provide an experimental basis for the clinical application of CFR-PEEK artificial joints to replace TMJ.Methods:Thirteen healthy adult Japanese rabbits were randomly divided into experimental group (n=6),positive control group (n=4) and negative control group (n =3).The right TMJ articular process of the rabbits in experimental group were resected to establish the joint defect models,and then the CFR-PEEK artificial joints were impanted.The right TMJ articular process of the rabbits in positive control group were resected,and the joint defect models were established without the CFR-PEEK artificial joint implantation.The rabbits in negative control group didn't receive any treatment.The body weights of the rabbits in each group were measured in 13 weeks.The effects of fixation and replacement after artificial joint implantation were assessed by CT imaging.Results:The TMJ articular process defect model was successfully implanted with the CFR-PEEK artificial joint.The CT imaging results after threedimensional reconstruction and CT images by contrast in vitro showed that the CFR-PEEK-implanted artificial joint was fixed well,it could be instead of the normal joint function.Compared with positive control group,the weights of rabbits in experimental group were significantly increased (P＜ 0.05) at 13 weeks;compared with positive control group,the weights of rabbits in experimental group and negative control group were both significantly increased (P＞0.05) at 13 weeks,but there was no significant difference between them (P＞0.05).The weights of rabbits in experimental group and negative control group kept normal growth;the weights of rabbits in positive control group was increased slowly,and even stopped growing or was negative.Conclusion:The CFR-PEEK artificial joint can be successfully implanted into the TMJ defect model and be used to repair the defect which help to restore chewing function.The CFR-PEEK is expected to be an ideal material for reconstructing TMJ.

Objective To explore the surgical feasibility and clinical efficacy of one-stage anterior-posterior approaches in treatment of severe fracture and dislocation of lower cervical spine in "beach chair position".Methods Sixteen male cases of severe fracture and dislocation of lower cervical spine and with a mean age of 49.8 years (range,36-78 years) treated surgically from May 2012 to May 2016 were analyzed retrospectively by using case series study.The segment of injury was C4-5 in 4 cases,C5-6 in 7 and C6-7 in 5.The degree of spinal cord injury according to the American Spine injury Association (ASIA) score was Grade A in 4 cases,Grade B in 7 and Grade C in 5.Sub-axial injury classification (SLIC) score was 8 points in 9 cases and 9 points in 7.After a general anesthesia,a ring with a hole was hanged on patient's head before the operation.Then,under the protection of hole traction,the upper of operating bed was swung up slowly,so that the patient was restricted in vertical "beach chair position" with traction on the halo in order to immobilize the head and partially reduce the kyphotic deformity.Routine cervical anterior-posterior approach was done with the exposure of damaged section of the front and rear structure.Pedicle screw system or lateral mass screw displacement was conducted.Anterior intervertebral discectomy or fracture vertebral was performed,using collaborative reset prying method before and after the road.In the front of intervertebral cage or titanium net support bone graft,rear pedicle screws or lateral mass screws fixation and bone graft fusion were implemented.The operation time and blood loss were recorded.The healing of the wound was observed.The recovery of neurological function was evaluated according to the ASIA grade.Postoperative review X-ray,CT and MRI were done to evaluate the reset and bone graft in position and fusion.Results All the surgeries were done well without aeroembolism and other related complications.The mean operative time was 153 minutes (range,150-180 minutes),and the mean amount of blood loss was 543 ml (range,400-800 ml).Sixteen cases were followed-up from 6 to 24 months (mean 13.7 months).All the incision were healed at Ⅰ stage.Spinal cord function did not aggravate.The ASIA grade was improved with an average of one to two Grades 6 months after surgery.Postoperative X-ray and CT confirmed that graft object position was favorable and cervical sequence was recovered well.The Cobb angle decreased from (23.6 ± 5.3) ° preoperatively to (4.0 ± 0.4)°postoperatively,and the translational displacement of vertebral body was restored into (2.7 ±0.4) mm (P ＜ 0.01) from (10.9 ± 1.6) mm before operation.The cervical spinal canal was not obstructed and the cervical spinal cord was relieved,showed by MRI.Conclusions One-stage anterior-posterior approaches for severe fracture and dislocation of lower cervical spine circumferential reconstruction in "beach chair position" is a beneficial and effective method,without the need of changing positions in a collaborative reduction and fixation.The method can reduce the interference of spinal cord,shorten the operation time and save anterior extra fixation.