Objective To investigate the effects of inclined axial compressive force and flexion moment on the anterior and posterior shear stiffness of the lumbosacral segment.Methods Six fresh-frozen human cadaveric L5-S1 segments were tested under intact and two progressively impaired structural conditions:intact,a 4-mm bilateral facet joint gap,and anterior discectomy with nucleus pulposus removal plus circumferential release of the inner annular fibers(disc injury).A 300 N axial compressive force was applied either vertically downward or with a 10° or 20° anterior inclination through the disc's shear center.Anterior(0 N to 250 N)and posterior(-50 N to 0 N)shear tests were conducted using a material testing machine.These tests were repeated under a 5 N-m flexion moment.The relative motion between L5 and Si was measured using a three-dimensional motion capture system.Results In the intact state,the inclination of the axial compressive force did not significantly alter anterior or posterior shear stiffness.However,the application of a flexion moment increased anterior shear stiffness by 49.3％.Progressive structural damage resulted in incremental increases in anteroposterior shear translation and corresponding reductions in stiffness.Notably,under combined loading with axial compression and flexion moment,anterior stiffness decreased from 939 N/mm(intact)to 224 N/mm(disc injury),while posterior stiffness decreased from 572 N/mm to 217 N/mm.Within the low-load range,no significant differences in shear stiffness were observed across any structural conditions,regardless of axial force inclination or combined with a flexion moment.Conclusions This study supports the clinical view that retro-inclination of the pelvis serves as a compensatory mechanism to enhance segmental shear stability.However,this compensatory capacity gradually diminishes and ultimately fails as spinal degeneration progresses.

Objective To investigate the effects of inclined axial compressive force and flexion moment on the anterior and posterior shear stiffness of the lumbosacral segment.Methods Six fresh-frozen human cadaveric L5-S1 segments were tested under intact and two progressively impaired structural conditions:intact,a 4-mm bilateral facet joint gap,and anterior discectomy with nucleus pulposus removal plus circumferential release of the inner annular fibers(disc injury).A 300 N axial compressive force was applied either vertically downward or with a 10° or 20° anterior inclination through the disc's shear center.Anterior(0 N to 250 N)and posterior(-50 N to 0 N)shear tests were conducted using a material testing machine.These tests were repeated under a 5 N-m flexion moment.The relative motion between L5 and Si was measured using a three-dimensional motion capture system.Results In the intact state,the inclination of the axial compressive force did not significantly alter anterior or posterior shear stiffness.However,the application of a flexion moment increased anterior shear stiffness by 49.3％.Progressive structural damage resulted in incremental increases in anteroposterior shear translation and corresponding reductions in stiffness.Notably,under combined loading with axial compression and flexion moment,anterior stiffness decreased from 939 N/mm(intact)to 224 N/mm(disc injury),while posterior stiffness decreased from 572 N/mm to 217 N/mm.Within the low-load range,no significant differences in shear stiffness were observed across any structural conditions,regardless of axial force inclination or combined with a flexion moment.Conclusions This study supports the clinical view that retro-inclination of the pelvis serves as a compensatory mechanism to enhance segmental shear stability.However,this compensatory capacity gradually diminishes and ultimately fails as spinal degeneration progresses.

Objective To explore the clinical diagnosis method of multiple primary malignancies (MPM) complicated with hepatocellular carcinoma (HCC). Methods Clinical data of 68 MPM patients complicated with HCC treated in the Sun Yat-sen University Cancer Center from January 1989 to April 2008 were retrospectively analyzed. There were 61 males and 7 females, aged from 32 to 82 years with a median age of 60 years. The informed consents of all patients were obtained and the local ethical committee approval had been received. The patients undergoing no surgery were diagnosed by imaging examination combined with detection of serum AFP level. Ultrasound-or CT-guided pathological biopsy was performed further on the suspected cases. The diagnosis was conifrmed by pathological examination in patients undergoing surgery.Results Of the 68 patients, 22 complicated with HCC simultaneously and 46 metachronously. The age of the ifrst onset of malignancy ranged from 31 to 76 years with a median age of 57 years. The age of onset of secondary malignancy ranged from 32 to 82 years with a median age of 60 years. Hepatitis B surface antigen (HBsAg) was detected in 45 patients, whereas hepatitis C antibody was negative in all cases. Fifty-one cases were complicated with liver cirrhosis. AFP≤25 g/L was detected in 30 cases and>25 g/L in 38 cases. Sixteen cases had a family history of malignant tumors. Thirty of the 33 patients undergoing no surgery were conifrmed based upon the typical HCC manifestations of imaging ifndings and AFP levels, including 16 cases were conifrmed by positron emission computed tomography (PET/CT). The remaining 3 suspected cases were conifrmed by ultrasound-or CT-guided liver biopsy. Thirty-ifve patients undergoing hepatic resection received pathological examination including 30 cases with single cancerous nodule and 5 with multiple cancerous nodules, 12 with tumor diameter<5 cm and 23 with tumor diameter≥5 cm. Twenty-seven patients were complicated with cirrhosis, 32 with vascular invasion, and 15 cases were found with surgical margin≥2 cm. Extrahepatic malignancies were distributed in different organs including head and neck tumors in 23 cases, digestive system tumors in 18 cases, urinary system tumors in 5 and other organ tumors in 22 cases. Conclusions The clinical characteristics of MPM complicated with HCC patients are similar to those of primary liver cancer patients. PET/CT probably possesses specific advantages in identifying MPM. Liver biopsy contributes to conifrming the diagnosis of suspected cases.

Objective To establish rabbit model of scoliosis induced with stable asymmetric lumbar loads. Methods Scoliosis was induced in 10 two-month-old New Zealand rabbits using 316L stainless steel springs placed between the unilateral transverse processes of L2 and L5. Serial radiographs were documented before and at 1, 4, 8, 9 and 12 weeks after the operation. At weeks, the rabbits were randomly divided into SR group (n=5) with the spring removed and SK group (n=5) without spring removal. Results All the rabbits survived the experiment with Cobb angle all greater than 10°at the end of the experiment. Significant changes were found in the Cobb angles and kyphotic angles at 1, 4 and 8 weeks after the operation (P<0.05). At 8 weeks, the Cobb angle, the kyphotic angle and the length of the spring were similar between SR and SK groups (P>0.05), and in the 4 weeks following spring removal in SR group, the Cobb angle and the kyphosis decreased significantly compared with those in SK group (P<0.05). Micro-CT showed that the BV/TV of the concave side was greater than that of the convex side. The length of the spring did not show obvious changes during the experiment (P>0.05). Conclusion Asymmetric lumbar loading is a convenient, time-saving, and highly reproducible approach for establishing rabbit models of scoliosis.

Objective To establish rabbit model of scoliosis induced with stable asymmetric lumbar loads. Methods Scoliosis was induced in 10 two-month-old New Zealand rabbits using 316L stainless steel springs placed between the unilateral transverse processes of L2 and L5. Serial radiographs were documented before and at 1, 4, 8, 9 and 12 weeks after the operation. At weeks, the rabbits were randomly divided into SR group (n=5) with the spring removed and SK group (n=5) without spring removal. Results All the rabbits survived the experiment with Cobb angle all greater than 10°at the end of the experiment. Significant changes were found in the Cobb angles and kyphotic angles at 1, 4 and 8 weeks after the operation (P<0.05). At 8 weeks, the Cobb angle, the kyphotic angle and the length of the spring were similar between SR and SK groups (P>0.05), and in the 4 weeks following spring removal in SR group, the Cobb angle and the kyphosis decreased significantly compared with those in SK group (P<0.05). Micro-CT showed that the BV/TV of the concave side was greater than that of the convex side. The length of the spring did not show obvious changes during the experiment (P>0.05). Conclusion Asymmetric lumbar loading is a convenient, time-saving, and highly reproducible approach for establishing rabbit models of scoliosis.

Objective: To investigate the safety and effectiveness of three-dimensional (3-D) rotational angiography reconstruction of left atrial and pulmonary vein stereo image embedded with real-time X-ray fluoroscopy system for guiding radiofrequency catheter ablation (RFCA) in treating the patients with atrial ifbrillation (AF).
Methods: A total of 60 consecutive AF patients who received RFCA in our hospital from 2011-04 to 2013-04 were studied. The patients were randomly divided into 2 groups and 3-D Carto3 mapping system was applied for guiding RFCA in both groups. n=30 in each group. Treatment group, the patients received Siemens ARTIS Zeego digital subtraction system for left atrial and pulmonary vein rotational angiography, then, stereo images were reconstructed and embedded with real-time X-ray lfuoroscopy for RFCA guidance. Control group, conventional left and right pulmonary venography was conducted for RFCA guidance. The procedural and X-ray exposure times, rates of success and complications were recorded and compared between 2 groups.
Results: All 60 patients had successful RFCA, compared with Control group, the patients in Treatment group had obviously less procedural time and X-ray exposure time, while the success rate and complications were similar between 2 groups.
Conclusion: 3-D rotational angiography reconstruction of left atrial and pulmonary vein stereo image embedded with real-time X-ray lfuoroscopy system is safe and effective for guiding RFCA in treating the AF patients, which may reduce the procedural and X-ray exposure times.