Ethyl acetate-soluble chemical constituents from branch of Hypericum petiolulatum / 中国中药杂志

The stems and branches of Hypericum petiolulatum were extracted by alcohol and liquid-liquid extraction. Seven furofuran lignans were isolated from the ethyl acetate fraction of ethanol extract of H. petiolulatum by using silica gelchromatography, Sephadex LH-20 chromatography, medium-pressure liquid chromatography and preparative HPLC. Their structures were identified by the spectroscopic methods as pinoresinol (1), medioresinol (2), 8-acetoxypinoresinol (3), epipinoresinol (4), (+)-syringaresinol (5), (+)-1-hydroxysyringaresinol (6) and erythro-buddlenolE (7). All the isolates were firstly found in H. petiolulatum. In the bioassay, compound 7 showed remarkable antioxidative activity inhibiting Fe(+2)-cystine induced rat liver microsomal lipid peroxidation with inhibitory rate 38% at a concentration of 1 x 10(-6) mol · L(-1) (positive control Vit E with the inhibitory rate of 35% at the same concentration).

Study of pedicle screw placement assisted by intraoperative three-dimensional navigation in lumbar vertebrae with axial rotation / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the effect of axial rotation of lumbar vertebrae on the accuracy of pedicle screw placement using the traditional method, as well as to assess the value of intraoperative three-dimensional (3D) navigation in improving the accuracy.</p><p><b>METHODS</b>Sixteen lumbar simulation models at different degrees of axial rotation (0°, 5°, 10° and 20°), with every four assigned with the same degree, were equally divided into two groups (traditional method group and intraoperative 3D navigation group). Random placement of pedicle screws was carried out, followed by CT scan postoperatively. Then the outer pedicle cortex contours were depicted from reconstructed sectional pedicle images using Photoshop. The accuracy of pedicle screw placement was evaluated by determining the interrelationship between screw trajectory and pedicle cortex (qualitative) and measuring the shortest distance from pedicle screw axis to outer cortex of the pedicle (quantitative).</p><p><b>RESULTS</b>Eighty pedicle screws were implanted respectively in each group. In traditional method group, statistical difference existed in the accuracy of pedicle screw placement at different axial rotational degrees (P < 0.05). With degrees increasing, the accuracy declined. The accuracy of intraoperative 3D navigation group was higher than traditional method group in vertebrae with axial rotation (P < 0.01). In qualitative evaluation, the accuracy of the two methods had statistical difference when the degree was 20°, and in quantitative evaluation, statistical difference existed in 5°, 10° and 20° of vertebral axial rotation.</p><p><b>CONCLUSIONS</b>Screw malposition can be caused by vertebral axial rotation in lumbar spine using traditional method. Accuracy of pedicle screw placement declines with the increase of axial rotational degrees. However, the accuracy can be improved by using intraoperative 3D navigation.</p>

Comparison of the clinical accuracy of cervical (C2-C7) pedicle screw insertion assisted by fluoroscopy, computed tomography-based navigation, and intraoperative three-dimensional C-arm navigation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The complicated anatomy of the cervical spine and the variation among pedicles reduces the accuracy and increases the risk of neurovascular complications associated with screw implantation in this region. In this study, we compared the accuracy of cervical (C2-C7) pedicle screw fixation assisted by X-ray fluoroscopy, computed tomography (CT)-based navigation, or intraoperative three-dimensional (3D) C-arm navigation.</p><p><b>METHODS</b>This prospective cohort study was performed in 82 consecutive patients who underwent cervical pedicle screw fixation. The accuracy of screw insertion was assessed by postoperative CT scan with 3D reconstruction. The accuracy of screw insertion was assessed as: excellent (screw completely within pedicle); acceptable (≤ 1 mm screw outside pedicle cortex); poor (> 1 mm screw outside pedicle cortex).</p><p><b>RESULTS</b>A total of 145 screws were inserted in 24 patients who underwent C-arm fluoroscopy. Of these, 96 screws (66.2%) were excellent, 37 (25.5%) were acceptable, and 12 (8.3%) were poor. One hundred and fifty-nine screws were inserted in 29 patients in the CT-based navigation group. Among these, 141 (88.7%) were excellent, 14 (8.8%) were acceptable, and 4 (2.5%) were poor. A total of 140 screws were inserted in 29 patients in the intraoperative 3D C-arm navigation group, of which 127 (90.7%) were excellent, and 13 (9.3%) were acceptable. No severe or permanent neurovascular complications associated with screw insertion were observed in any patient.</p><p><b>CONCLUSIONS</b>CT-based and intraoperative 3D C-arm navigation were similarly accurate, and were both significantly more accurate than C-arm fluoroscopy for guiding cervical pedicle screw fixation. They were able to accurately guide the angle and depth of screw placement using visual 3D images. These two techniques are therefore preferable for high-risk cervical pedicle screw fixation. The ease and convenience of intraoperative 3D C-arm navigation suggests that it may replace virtual-fluoroscopy and CT-based navigation systems in future clinical applications.</p>

Accuracy of CT-based navigation of pedicle screws implantation in the cervical spine compared with X-ray fluoroscopy technique / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility and accuracy of cervical spine pedicle screw fixation assisted by X-ray fluoroscopy and CT-based navigation system.</p><p><b>METHODS</b>145 cervical pedicle screws were placed assisted by X-ray fluoroscopy and 159 cervical pedicle screws were placed assisted by CT-based navigation system. Screw positions were evaluated by postoperative CT scans or C-arm X-ray 3 dimensional reconstruction.</p><p><b>RESULTS</b>In the computer- assisted group, 155 (97.5%) screws were found completely within their pedicles compared with 133 (91.7%) correctly placed screws in the X-ray assisted group (P < 0.05). The process of navigation investigated in twenty patients showed that the mean time for registration and surface matching was 3.5 (range from 2 to 8 minutes) minutes and the mean time for screw-marker insertion was 2 (range from 1 to 3.5 minutes) minutes with the mean position deviation 0.31 mm (0.12-0.56 mm) per screw. Only twice C-arm fluoroscopy were performed to verify the accuracy of one screw position intraoperatively. No severe complications like neurovascular lesion occurred in both groups.</p><p><b>CONCLUSION</b>CT-based navigation system can increase the accuracy of cervical pedicle screw implantation significantly.</p>