This paper introduces the hardware and software of a biomechanical robot-based testing device. The bottom control orders, posture and torque data transmission, and the control algorithms are integrated in a unified visual control platform by Visual C+ +, with easy control and management. By using hybrid force-displacement control method to load the human spine, we can test the organizational structure and the force state of the FSU (Functional spinal unit) well, which overcomes the shortcomings due to the separation of the force and displacement measurement, thus greatly improves the measurement accuracy. Also it is esay to identify the spinal degeneration and the load-bearing impact on the organizational structure of the FSU after various types of surgery.
Algorithms ; Biomechanical Phenomena ; Equipment Design ; Humans ; Joints ; physiology ; Robotics ; instrumentation ; methods ; Software ; Spine ; physiology

Objective To compare the stability effect of the fixation segment using the new test system based robotics to simulate the complex human movement at natural state about the three-level fixa-tion by using four, five or six pedicle screws in treatment of thoracolumbar burst fractures. Methods Six human cadaveric spines were dissected from T_(11)-L_3. The inferior half part of L_1 vertebral bodies and L_1-L_2 dises were resected to mimie an unstable L_1 burst fracture with loss of anterior column support. Specimens were tested in accordance with the following order:intact, 4,5 and 6 pedicle screws fixation at the three-level fixation. The range of motion (ROM) of the fixation segment (T_(11)-L_3) was measured with the six-freedom degree robotics system controlled by mixed force and displacement during flexion, exten-sion, lateral bending and axial torsion, when the stiffness was calculated. One-way statistieal analysis was used for analyzing the collected data. Results With increased number of screws, the ROM of the fixa-tion segment (T_(11)-L_3) was gradually decreased and the stiffness gradually increased. The ROM under ax-ial rotation of six and five screws group became smaller than four screws group (P < 0.05). The stiffness under axial rotation of six screws group was higher than four screws group (P < 0.05). There was no sta-tistical difference between five screws group and four screws group in regard of the stiffness in axial rota-tion (P > 0.05). There were no significant differences in ROM and stiffness under six different loading directions between six screws group and five screws group (P > 0.05). No statistical difference was observed for three fixation modes in aspects of ROMs and stiffness under flexion-extension or lateral ben-ding (P > 0.05). Conclusions Three-level fixation of burst fractures with five or six screws offers im-proved biomechanical stability compared with traditional four screws fixation. But the difference is insig-nificant between six and five screws fixations.

This is a report on how we use the hybrid force-displacement control method to load the human knee and analyze the effect and value of our robot experimental system through the biomechanical experiments of total meniscal resection of human knee. The whole robot control system can load continuously on the specimens, thus overcoming the shortcomings of the traditional loading methods which can only load discretely. In the meantime, by using the robot-based testing system, the force (torque) of the specimens and the spatial position under the force can be measured in real-time, which overcomes the shortcomings caused by the separation of force (torque) measurement from displacement measurement and so greatly improves the measurement accuracy.
Adult ; Biomechanical Phenomena ; Cadaver ; Female ; Humans ; Knee Joint ; physiology ; Male ; Menisci, Tibial ; surgery ; Middle Aged ; Robotics ; methods ; Torque ; Weight-Bearing ; physiology

Objective To investigate the clinical effect of distal radioulnar ligament reconstruction by autologous tendon pal‐maris longus transplantation under arthroscopic assistance in treating chronic instability of the distal radioulnar joint .Methods Seven patients with chronic instability of the distal radioulnar joint after failure of conservation therapy were definitely diagnosed by the wrist joint exploration .Then the autologous tendon palmaris longus was taken for conducting the anatomical reconstruction of distal radioulnar ligament ;the average follow up was 12 months .The preoperative and postoperative grip strength and the motion of wrist joint were recorded ;the pain status of the wrist joint was evaluated by using the visual analogue scale (VAS) ,and the wrist function status was evaluated by using the Disabilities of the Arm ,Shoulder and Hand(DASH) and the Modified Mayo Wrist Score (MMWS) .Results The average VAS score of the rist joint motion was recovered from (7 ± 2) points before operation to (3 ± 3) points after operation ,the MMWS score was improved from preoperative (50 ± 9) points to postoperative (83 ± 11) points ,the DASH score was decreased significantly from preoperative (37 ± 15) points to postoperative (16 ± 10) points ,the grip strength was improved from preoperative 84 .5 ± 16 .0 to postoperative 93 .4 ± 11 .0 ,the differences were statistically significant .The mean range of motion(ROM ) in flexion/extension of the wrist was increased from preoperative 93 .5% ± 6 .0% to postoperative 96 .4% ± 3 .0% ,the ROM in pronation/supination of the forearm was increased from preoperative 92 .6% ± 7 .0% to postoperative 97 .2% ± 5 .0% ,but the differences were not statistically significant .Conclusion Under arthroscopic assistance ,the anatomical reconstruc‐tion of the distal radioulnar ligaments is an effective treatment method for treating chronic distal radioulnar joint instability ,its short term follow up has satisfactory effect .

Objective To investigate the application value of multiple?arterial?phase imaging technique with differential sub?sampling with cartesian ordering (DISCO) in the gadoxetate acid disodium enhanced liver MRI. Methods From September 2017 to March 2018, 56 patients with suspected malignant focal liver disease diagnosed with ultrasound or CT in West China Hospital of Sichuan University were enrolled prospectively, and underwent preoperative enhanced MRI with gadoxetate acid disodium. Patients were divided into 2 groups by random?number table method. Twenty nine patients in group A underwent liver multiple?arterial?phase imaging with DISCO. Twenty seven patients in group B underwent single?arterial?phase imaging with liver acquisition with volume acceleration?flex (LAVA?Flex). The display rate of late?arterial?phase and respiratory motion artifacts of dynamic enhancement images were evaluated. The categorical variables was compared by Chi?square test. The respiratory motion artifacts between the single?arterial?phase and multiple?arterial?phases were compared by Mann?Whitney U test. The artifact scores among the various phases of the multi?arterial phase were compared by Kruskal?Wallis H. Results Compared to LAVA?Flex [74.1%(20/27)], a higher display rate of late?arterial phase [96.6%(28/29)] was found in DISCO (Group A), and the difference was statistically significant (χ2=5.770, P=0.016). In the evaluation of respiratory motion artifacts, the motion artifacts of the late?arterial images obtained by LAVA?Flex [3(3,4)] were more severe than the DISCO [2(2,3)], and the difference was statistically significant (Z=-3.250, P<0.01). Among the scores of motion artifacts in the 6 phases of DISCO, the artifact scores of phase 1, 2, 3, 4, 5, 6 were [3(3,4)], [2(2,3)], [2(2,3)], [3(2,3)], [3(3,4)] and [3(3,4)], respectively. The motion artifacts of phase 2, 3, 4 were better than phase 1, 5, 6, the differences were statistically significant (P<0.05), but there was no statistical differences among phase 2, 3 and 4 (P>0.05). Conclusion Compared with single?arterial?phase imaging, multiple?arterial?phases with DISCO using gadoxetate acid disodium can improve the capture rate of late arterial phase and reduce motion artifacts.

Objective To investigate the possible presence of radiation brain injury (RBI) in vascular injury and blood-brain barrier (BBB) damage.Methods Seventy 8 weeks old male BALB/C mice were randomly divided into irradiation group and control group;mice in the two groups received whole-brain exposure with a single dose of 10 Gy irradiation or sham irradiation.Tissue samples were taken 1,7,30,90 and 180 days after irradiation (7 mice in each time point per group);HE staining was used to observe the microvascular morphology and density changes;immune-fluorescence staining was used to visualize the differential expressions of factor Ⅷ related antigen (vWF) and zonulaoccludens-1 (ZO-1).Results Micro-vascular disorders began to appear from the first day of irradiation,deteriorating with time extension gradually.After the X-ray irradiation exposure,the protein expressions of vWF and ZO-1 in the irradiation group were significantly decreased as compared with those in the control group 1,7,30,90 and 180 days after irradiation (vWF:23.17±2.93 vs 15.80±2.39,21.25±2.33 vs 11.60±2.3,19.78±2.16 vs 8.20±1.64,17.21±3.31 vs 6.00±2.12 and 16.98±1.92 vs 3.80±2.59;ZO1:26.17±3.31 vs 15.40±1.82,23.20±2.93 vs 12.00±1.58,20.88±2.20 vs 9.10±2.55,18.32±1.87 vs 6.20±1.92 and 17.50±1.91 vs 2.40±1.52,P＜0.05);besides,the decreased expression ofvWF and ZO-1 in the irradiation group showed a time-depended manner,with significant differences between each two time points (P＜0.05).Conclusion X-rays may induce persistent micro-vascular injury and destroyed BBB tight junctions,which may be closely related to the occurrence and development of RBI.

Objective To evaluate the clinical and radiological results of Phlios plate and Multiloc nail in treatment of proximal humerus fractures.Methods From February 2013 to December 2015,data of 37 cases of proximal humerus fractures who were treated by reduction and fixation using Phlios plate or Multiloc nail were retrospectively analyzed.In group one (Phlios plate),there were 10 males and 8 females,with an average age of 56.3±5.8 years,including 7 cases of Neer 2-part surgical neck fracture,6 cases of Neer 3-part fracture,4 cases of Neer 4-part fracture,and 1 case of fracture-dislocation.In group two (Multiloc nail),there were 8 males and 11 females,with an average age of 57.2±7.4 years,including 8 cases of Neer 2-part surgical neck fracture,9 cases of Neer 3-part fracture,1 case of Neer 4-part fracture,and 1 case of fracture-dislocation.Operation time,range of motion of shoulder joint,visual analogue scale (VAS) pain score,American Shoulder & Elbow Surgeon (ASES) score and ConstantMurley score were collected.Results All 37 patients were followed up for an average period of 15.5 months (range,12-36 months).The average bone healing time were 2.5±0.5 months (range,2-3 months)and 2.2±0.5 months (range,1.5-3 months) in the plate and nail group respectively.At the latest follow-up,average VAS score was 0.4±0.6 (range,0-2),the ASES score aver aged 85.4±6.8 points (range,73-96),Constant-Murley score averaged 83.4±7.3 points (range,71-94),and external rotation averaged 30.8°±10.0° (range,10°-50°) in plate group,while average VAS score was 0.2±0.4 (range,0-1),ASES score averaged 89.7± 5.6 points (range,80-98),Constant-Murley score averaged 88.5±6.8 points (range,76-98),and external rotation averaged 40.3°± 7.9° (range,20°-50°) in the intramedullary nailing group.One case had partial necrosis of humeral head in the plate group,while 1 case suffered absorption of the greater tuberosity in the nail group,with the complication rate of 5.6％ (1/18) and 5.3％ (1/19) respectively,without significant difference.The internal and external rotation degrees,ASES and Constant-Murley scores were better in nail group than those in plate group for 2-part fractures,while the forward elevation and abduction degrees were similar.Conclusion Similar results were achieved for the treatment of proximal humeral fractures by Phlios plate and Multiloc nail.The Multiloc nailing group had achieved superior outcomes in Neer-2-part proximal humeral fractures.

Objective To investigate the value of multi?arterial phase differential sub?sampling with cartesian ordering (DISCO) technique in the evaluation of hepatic vascular anatomy with gadolinium?ethoxybenzyl?diethylenetriamine pentaacetic acid (Gd?EOB?DTPA). Methods Forty?eight patients with suspected hepatic malignancy were prospectively enrolled and underwent both of Gd?EOB?DTPA enhanced DISCO MRI and CTA within two weeks. The hepatic arterial anatomy of two examination methods were evaluated by four?point scoring method. The arterial scores between DISCO and CTA images were compared by Wilcoxon test. The difference among multiple arterial scores of DISCO and CTA were compared by Kruskal?Wallis H test respectively. Results There was no difference of arterial scores in celiac artery, common hepatic artery, proper hepatic artery, left hepatic artery, right hepatic artery, first branch of right hepatic artery, splenic artery, left gastric artery and gastroduodenal artery between DISCO and CTA (P>0.05), but the arterial score of first branch of left hepatic artery [2 (2,2)] was lower than that of CTA [2 (2,3)] (Z=-3.138,P=0.002). In the multiple comparison among different arteries, there were differences between PHA and LAH (P<0.05), B?LHA and B?RHA (P<0.05) in DISCO, but no difference was found in CTA (P>0.05). Conclusion The DISCO sequence with Gd?EOB?DTPA enhancement MRI can supply comparable image quality to CTA in hepatic artery and its main branches display, which has no ionizing radiation and can also provide more diagnostic information for clinic.

Objective: To investigate the application value of multiple-arterial-phase imaging technique with differential sub-sampling with cartesian ordering (DISCO) in the gadoxetate acid disodium enhanced liver MRI. Methods: From September 2017 to March 2018, 56 patients with suspected malignant focal liver disease diagnosed with ultrasound or CT in West China Hospital of Sichuan University were enrolled prospectively, and underwent preoperative enhanced MRI with gadoxetate acid disodium. Patients were divided into 2 groups by random-number table method. Twenty nine patients in group A underwent liver multiple-arterial-phase imaging with DISCO. Twenty seven patients in group B underwent single-arterial-phase imaging with liver acquisition with volume acceleration-flex (LAVA-Flex). The display rate of late-arterial-phase and respiratory motion artifacts of dynamic enhancement images were evaluated. The categorical variables was compared by Chi-square test. The respiratory motion artifacts between the single-arterial-phase and multiple-arterial-phases were compared by Mann-Whitney U test. The artifact scores among the various phases of the multi-arterial phase were compared by Kruskal-Wallis H. Results: Compared to LAVA-Flex [74.1%(20/27)], a higher display rate of late-arterial phase [96.6%(28/29)] was found in DISCO (Group A), and the difference was statistically significant (χ²=5.770, P=0.016). In the evaluation of respiratory motion artifacts, the motion artifacts of the late-arterial images obtained by LAVA-Flex [3(3,4)] were more severe than the DISCO [2(2,3)], and the difference was statistically significant (Z=-3.250, P<0.01). Among the scores of motion artifacts in the 6 phases of DISCO, the artifact scores of phase 1, 2, 3, 4, 5, 6 were [3(3,4)], [2(2,3)], [2(2,3)], [3(2,3)], [3(3,4)] and [3(3,4)], respectively. The motion artifacts of phase 2, 3, 4 were better than phase 1, 5, 6, the differences were statistically significant (P<0.05), but there was no statistical differences among phase 2, 3 and 4 (P>0.05). Conclusion Compared with single-arterial-phase imaging, multiple-arterial-phases with DISCO using gadoxetate acid disodium can improve the capture rate of late arterial phase and reduce motion artifacts.

Objective: To investigate the value of multi-arterial phase differential sub-sampling with cartesian ordering (DISCO) technique in the evaluation of hepatic vascular anatomy with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA). Methods: Forty-eight patients with suspected hepatic malignancy were prospectively enrolled and underwent both of Gd-EOB-DTPA enhanced DISCO MRI and CTA within two weeks. The hepatic arterial anatomy of two examination methods were evaluated by four-point scoring method. The arterial scores between DISCO and CTA images were compared by Wilcoxon test. The difference among multiple arterial scores of DISCO and CTA were compared by Kruskal-Wallis H test respectively. Results: There was no difference of arterial scores in celiac artery, common hepatic artery, proper hepatic artery, left hepatic artery, right hepatic artery, first branch of right hepatic artery, splenic artery, left gastric artery and gastroduodenal artery between DISCO and CTA (P>0.05), but the arterial score of first branch of left hepatic artery [2 (2,2)] was lower than that of CTA [2 (2,3)] (Z=-3.138,P=0.002). In the multiple comparison among different arteries, there were differences between PHA and LAH (P<0.05), B-LHA and B-RHA (P<0.05) in DISCO, but no difference was found in CTA (P>0.05). Conclusion The DISCO sequence with Gd-EOB-DTPA enhancement MRI can supply comparable image quality to CTA in hepatic artery and its main branches display, which has no ionizing radiation and can also provide more diagnostic information for clinic.