Objective To observe and compare in vivo segmental lumbar motion between symptomatic L4 isthmic spondy?lolisthesis (IS) patients and L4 degenerative spondylolisthesis (DS) patients during functional weight?bearing activities. Methods Fifteen symptomatic L4 IS patients and fifteen symptomatic L4 DS patients were recruited. Fifteen asymptomatic volunteers were en?rolled as the control group. The L4,5 vertebral segment motion of each subject was reconstructed using three?dimensional computed tomography and a solid modeling software. In vivo, lumbar vertebral motion during functional postures (flexion?extension, left?right twisting and left?right bending) was observed using a dual fluoroscopic imaging technique. The spinal function unit was divided in?to anterior and posterior segments by the isthmic cleft. Local coordinate systems were established at the vertebral body, to obtain the 6 degree?of?freedom (DOF) intervertebral range of motion (ROM) at L4,5 and the ROM between the anterior and the posterior segments of L4 IS. Results The motion of IS at L4,5 was found to be increased. The migrations along both sagittal and vertical axis were significantly larger than control group (P<0.05). During left?right twisting, the migration along sagittal axis was significantly larger than control group (P<0.05);the rotation along vertical axis was significantly larger than DS and control group (P<0.05). During left?right bending, the migration along frontal axis was significantly larger than DS and control group ( P<0.05). The inter?vertebral ROM at L4,5 showed no significant difference between DS and control group. The migration between anterior and posteri?or segments of IS L4 was larger in standing than supine (P<0.05). The relative migration along sagittal axis between anterior and posterior segments of IS L4 was significantly larger in flexion than standing (P<0.05). Conclusion A spondylolytic defect does lead to detectable instability or hypermobility in the lumbar spine compared with degenerative spondylolisthesis and normal group. From supine to standing posture, migration at isthmic cleft along sagittal and coronal axis are identified in IS spondylolithesis.

Objective: To evaluate the quality of Japanese Encephalitis (JE) case reports based on the establishment of surveillance on acute meningitis and encephalitis syndrome (AMES) in Baoji. Methods: A surveillance network on AMES cases was set up in Baoji city of Shaanxi province between July 2013 and December 2016. All the cases met the surveillance definition of AMES cases were conducted a questionnaire, collected serum and/or cerebrospinal fluid (CSF) specimens to test JE immunoglobulin M antibodies by using enzyme-linkedimmunosorbent assay methods.The information of the incidence of JE in Shaanxi and Baoji from 2009 to 2016 originated from the China information system for disease control and prevention. Chi square test was used to compare the difference in JE incidence in Baoji, Shaanxi before and after the implementation of AMES monitoring project. Results: 75 out of 855 collected cases were laboratory confirmed as JE, Including 42 suspected JE cases and 33 other suspected cases diagnosed after hospitalization. Except 1 case occurring in December, all the other cases occurred between July and October, especially in August with a peak of 55 cases (73.3%), and 6 cases (8.0%) in July, 11 cases (14.7%) in September, 2 cases (2.7%) in October. The proportion of patients aging 0-6, 7-14 and ≥15 years old were respectively 4.0% (3 cases), 8.0% (6 cases) and 88.0% (66 cases). The biochemical test showed the cerebrospinal fluid in 13 cases (17.3%) were slightly turbid, the white blood cell in 31 cases (41.3%) elevated, the glucose levels in 24 cases (32.0%) were abnormal, and the chloride level in 23 cases (30.7%) were abnormal. A total of 103 cases of JE were diagnosed in Baoji from 2009 to 2016, with an average annual incidence rate at 0.34/100 000. The average incidence of JE in 2009-2012 and 2013-2016 was 0.21/100 000 and 0.48/100 000 respectively. From 2013 to 2016, the proportion of JE cases in Baoji, Shaanxi was 19.3% (71/369), and it was 8.9% (32/362) between 2009 and 2012 (χ²=4.15, P=0.040). Conclusion The AMES surveillance project improved the quality of the JE case report in Baoji. Changes appeared in biochemistrical and epidemiological characteristics of cerebrospinal fluid. The incidence of JE was seriously underestimated in Shaanxi province and therefore the sensitivity of Japanese encephalitis surveillance cases should be further improved.

Objective:To analyze the biomechanical characteristics of bilateral lumbo-iliac fixation by finite element analysis after digital optimization of a safe screw pathway.Methods:Firstly, a healthy adult male volunteer was recruited for this study who underwent CT scanning of the lumbus and pelvis, with a slice thickness of 0.625 mm.The original data were imported into Mimics 16.0 software for 3D lumbar and pelvic reconstruction.At the same time, a geometric screw pathway and a free screw pathway were generated in the pedicles of L4 and L5 and ilium.Secondly, all 3D models were imported into Ansys 12 software to assemble a finite element model.The displacements and von Misses stress distribution were measured in the conditions of forward bending, backward extending, lateral bending to the left and right, and left and right rotations in the models of 2 kinds of pathway after gravity axial load of 500 N was applied.Results:The models of 2 different pathways were similar in comprehensive displacement and stress in the conditions of forward bending, lateral bending and backward extending, and in the maximum stress of the screw in the conditions of forward bending and lateral bending.However, the comprehensive displacement and stress in the condition of rotation and the stress of the screw in the conditions of backward extending and rotating in the model of geometric screw pathway were obviously smaller than those in the model of free screw pathway.The maximum pelvic stress was on the screw surface between 190 and 260 MPa, concentrated on the bending area of the 2 screws connecting the sacrum and vertebral body.The lumbar-iliac fixation model showed high com-pressive stiffness.The maximum von Misses stress appeared in the L4-L5 pedicle screw on the longitudinal rod.Under rotational loading, the upper longitudinal rod connecting the L4-L5 pedicle screw and the iliac bone screw bore the maximum stress.Conclusions:Our finite element analysis shows that double verte-bral bodies and long screw fixation are effective ways of iliolumbar fixation.The geometric screw path optimized by digital analysis exhibits better fatigue resistance, rotation resistance and overall stability.Internal lum-bo-iliac fixation can effectively share the stress of vertebral bodies.

Objective:To evaluate the accuracy of an ultrasound-guided robot-assisted system for percutaneous facet joint puncture in an animal experiment by registration of ultrasound images and two-dimensional X-ray fluorescence images.Methods:Six specimens of fresh adult sheep lumbar spine were prepared and soaked in gelatin solution. The specimens contained a total of 48 facet joints with 24 ones respectively on the left and right sides. Half of the joints were assigned by the random number table method into a robot-assisted group which were subjected to percutaneous facet joint puncture assisted by the ultrasound-guided robot-assisted system while the contralateral ones into a freehand group which were subjected to percutaneous facet joint puncture by freehand. In the robot-assisted group, the left facet joints were 3 L 1, 3 L 2, 3 L 3 and 3 L 4 ones while the right facet joints were 2 L 1, 3 L 2, 5 L 3 and 2 L 4 ones. In this self-control animal experiment, both the robot-assisted punctures and the freehand punctures were carried out in the same specimen. The puncture success rate, puncture needle adjustment, positioning deviation, orientation deviation and operation time were recorded. Results:The positioning deviation and orientation deviation in the robot-assisted group [(2.21 ± 1.12) mm and 1.51° ± 0.47°] were significantly lower than those in the freehand group [(3.26 ± 1.44) mm and 2.24° ± 0.89°] ( P < 0.05). All the articular facet joint punctures were successfully accomplished for the first time in the robot-assisted group while those required multiple adjustments in the freehand group. In the robot-assisted group, the total operation time [(463.84 ± 34.93) s] was significantly longer than that in the freehand group [(298.40 ± 27.48) s], but the puncture time [(37.97 ± 6.87) s] was significantly shorter than that in the freehand group [(261.61 ± 33.15) s] ( P < 0.05). Conclusion:The ultrasound-guided robot-assisted system for percutaneous facet joint puncture can lead to accurate puncture with limited needle adjustments.

Anterior cruciate ligament (ACL) deficiency is a common clinical injury that seriously affects the function of the knee. Although ACL reconstruction (ACLR) can rebuild the structure of the ACL, it does not restore the normal kinematics and dynamics of the knee. In recent years, motion analysis has been widely applied in sports science and rehabilitation. In clinics, motion analysis is mainly applied to the evaluation of clinical outcomes of the ACLR knee. It is also a scientific objective tool to assess the potential risk factors of secondary injury and early onset of osteoarthritis after ACLR. In-depth understanding of the knee functional kinematics and kinetics after ACLR will significantly improve the efficacy of current ACL deficiency treatment and rehabilitation regime. This paper reviewed studies of the knee joint motion analysis after ACLR in the past decade. The current knowledge of the ACLR knee motion from studies using optical motion capture and biplanar fluoroscopic imaging system based tracking technique was synthesized. Clinical studies have reported that regardless of the type of graft and surgical technique of the ACLR, the postoperative knee still exhibits abnormal kinematics in functional tasks, but the relationship between early-onset OA and the biomechanical changes in the ACLR knee remains unknown. Restoring the rotational stability of the knee is still one of the biggest challenges in clinical ACLR surgery. Future studies should explore the impact of ACLR on the biomechanical mechanisms of the knee joint through an appropriate research design and long-term follow-up, and help clinicians and physiotherapists to develop more effective interventions.

Enterotoxigenic Escherichia coli（ETEC）infection can induce watery diarrhea，leading to dehydration，electrolyte disturbance，and even death in severe cases. Recombinant B subunit/inactivated whole-cell cholera（rBS/WC）vaccine is effective in preventing ETEC infectious diarrhea. On the basis of the latest evidence on etiology and epidemiology of ETEC，as well as the effectiveness，safety，and health economics of rBS/WC vaccine，National Clinical Research Center for Child Health（The Children’s Hospital，Zhejiang University School of Medicine）and Zhejiang Provincial Center for Disease Control and Prevention invited experts to develop expert consensus on rBS/WC vaccine in prevention of ETEC infectious diarrhea. It aims to provide the clinicians and vaccination professionals with guidelines on using rBS/WC vaccine to reduce the incidence of ETEC infectious diarrhea.