[Ethyl acetate-soluble chemical constituents from branch of Hypericum petiolulatum].

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).

[Posterior C1-C2 transarticular screw fixation for atlantoaxial instability assisted by intraoperative 3-dimensional fluoroscopy-based navigation].

OBJECTIVE: To assess the feasibility, efficacy and indication of posterior C1-C2 transarticular screw fixation for atlantoaxial instability assisted by intraoperative 3-dimensional fluoroscopy-based navigation. METHODS: From November 2005 to October 2012, 58 patients with atlantoaxial instability underwent posterior C1-C2 transarticular screw fixation assisted by intraoperative 3-dimensional fluoroscopy-based navigation. Those with excellent atlantoaxial reduction and no need for decompression underwent percutaneously minimally invasive procedures. Operative duration, blood loss volume, reduction of atlantoaxial joints and postoperative neurovascular complications were recorded. Screw positions were studied by postoperative computed tomography (CT) and divided into 3 categories. The follow-up period was at least 3 months. Local symptoms (assessed by visual analogue scale (VAS) score), neurological conditions (Nurick classification) and bone graft fusion were evaluated. RESULTS: Among them, the procedure was either open surgery (n = 51) or percutaneously minimally invasive surgery (n = 7). A total of 111 screws were placed satisfactorily. Five patients underwent only unilateral C1-C2 transarticular screw fixation. No severe complications were encountered. The mean operative duration was 202.2 ± 54.2 minutes and the average volume of blood loss 412.6 ± 281.2 ml. And the values were comparable to those for the traditional fluoroscopy-guided free-hand procedures. No statistical significance existed between open and percutaneously minimally invasive procedures in operative duration, blood loss volume and precision of screw placement. The patients with incompletely reduced C1-C2 dislocation had comparable clinical outcomes with those with complete reduction. After a 3-month follow-up, all of them showed significant improvements of local symptoms. VAS score decreased from 4.5 ± 1.3 preoperatively to 0.7 ± 0.8 postoperatively while the Nurick classification improved from 2.4 ± 1.1 to 0.6 ± 1.0. And bone graft fusion was satisfactory. CONCLUSIONS: Posterior C1-C2 transarticular screw fixation for atlantoaxial instability assisted by intraoperative 3-dimensional fluoroscopy-based navigation is both feasible and safe. Combined with minimally invasive techniques, this procedure may achieve greater precision and minimal invasion.

Posterior fixation and fusion of unstable Hangman's fracture by using intraoperative three-dimensional fluoroscopy-based navigation.

PURPOSE: The purpose of this study was to assess the efficacy and accuracy of posterior screw fixation for unstable Hangman's fracture using intraoperative 3D fluoroscopy-based navigation. METHODS: 14 patients with unstable Hangman's fractures (11 males and 3 females), ranging in age from 21 to 59 years, received posterior fixation assisted by an intraoperative 3D fluoroscopy-based navigation system: 11 Levine-Edwards type II and three type IIA cases. The American Spine Injury Association grade was D in 2 and E in 12 cases. RESULTS: Operation time was 110 min (range 90-140 min). Hospital stay was 7.6 days (range 5-12 days). All the patients were observed for an average of 28.8 months (range 15-50 months). No screw-related injury to nerve, or vertebral artery was observed intraoperatively. An average of four screws/patient were inserted. Pedicle screws were placed into C2 and C3, and 5 screws were into the lateral mass of C3. Screw placement accuracy was evaluated using postoperative CT, according to the modified classification of Gertzbein and Robbins; one screw was grade 2 in C2, and three screws were grade 2 in the pedicle of C3. No grade 3 misplacement or clinical deficits were noted. C3 lateral mass screws were successfully inserted. Neck pain was relieved in each case. Neurologic status improved from D to E in 2 cases. Solid fusion was demonstrated in all the cases by static and dynamic films during the final follow-up. CONCLUSIONS: This case series demonstrates that intraoperative 3D fluoroscopy-based navigation is a safe, accurate, and effective tool for screw placement in patients with unstable Hangman's fracture.

[Study of pedicle screw placement assisted by intraoperative three-dimensional navigation in lumbar vertebrae with axial rotation].

OBJECTIVE: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.

Determination of trace lithium in uranium compounds by adsorption on activated alumina using a micro-column method.

A novel method using a micro-column packed with active alumina as solid phase was proposed for separation of trace lithium from uranium compounds prior to determination. The method is based on a preliminary chromatographic separation of the total amount of uranium. This separation involves passing the solution containing sodium carbonate through active alumina and then eluting the trace lithium retained by the solid phase with a solution of sulfuric acid. Two modes, off-line and on-line micro-column preconcentration, were performed. In conjunction with atomic absorption spectrometry, this on-line preconcentration technique allows a determination of lithium at 10(-9) level. Both off-line and on-line mode operation conditions were investigated in separation and determination of trace lithium by micro-column method (length of column bed, flow rate, etc.). The adsorption capacity of activated alumina was found to be 343 microg g(-1) for lithium. Under the optimal operation condition, the detection limit (DL) of on-line preconcentration corresponding to three times the standard deviation of the blank (S/N = 3) was found to be 1.3 ng mL(-1) and the RSD of this method is 3.32% (n = 5). The on-line calibration graph was linear over the range 20 - 200 ng mL(-1). A good preconcentration factor 820 was achieved by experiment under the on-line mode. The developed method was applied to the analysis of trace lithium in nuclear grade uranium compounds.

[Early clinical outcome of cervical artificial disc replacement].

OBJECTIVE: To summarize the experience of cervical artificial disc replacement. METHODS: The clinical data of 29 cases undergoing standard Bryan artificial disc replacement, 15 males, aged 47 (32 approximately 60), and 14 females, aged 49 (40 approximately 65), 16 with cervical spondylotic myelopathy and 13 with cervical disc herniation, were analyzed. Twenty patients underwent replacement of one disc and 4 patients underwent replacement of 2 discs. A follow-up of 3.7 months was conducted. RESULTS: No complication was seen intra-operatively and post-operatively. All patients felt improvement of preoperative symptoms immediately postoperatively and returned to work 2 approximately 4 weeks after the operation. The JOA scoring was improved by 56%. The average motion range of the operative intervertebral space was 12.2 degrees before operation and was 10.9 degrees after the operation in vertical direction. The average motion range of the operative intervertebral space in vertical direction was 12.2 degrees before operation and was 10.9 degrees after the operation. The average motion range of the adjacent intervertebral space in vertical direction was 10.9 degrees before operation and was 9.4 degrees after the operation. The satisfaction rate of the patients was 94%. CONCLUSION: The short-term effect of standard Bryan artificial disc replacement is satisfactory.

[Accuracy of CT-based navigation of pedicle screws implantation in the cervical spine compared with X-ray fluoroscopy technique].

OBJECTIVE: To evaluate the feasibility and accuracy of cervical spine pedicle screw fixation assisted by X-ray fluoroscopy and CT-based navigation system. METHODS: 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. RESULTS: 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. CONCLUSION: CT-based navigation system can increase the accuracy of cervical pedicle screw implantation significantly.

Surgical management of symptomatic os odontoideum with posterior screw fixation performed using the magerl and harms techniques with intraoperative 3-dimensional fluoroscopy-based navigation.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To evaluate the accuracy of screw fixation using intraoperative three-dimensional fluoroscopy-based navigation (ITFN) and to assess the clinical outcomes of this treatment regimen. SUMMARY OF BACKGROUND DATA: The surgical management of symptomatic os odontoideum poses considerable difficulties due to the highly variable anatomy of the upper cervical spine and surrounding neurovascular structures. Various methods have been described for the treatment of symptomatic os odontoideum, all of which have limitations. METHODS: Nineteen patients with symptomatic os odontoideum were investigated. Pain scores were assessed using the visual analogue scale. Myelopathy was assessed using the Nurick scale and Odom's criteria. Radiological imaging was carried out in all patients for diagnosis and to assess the atlantodens interval, space available for cord, and presence of intramedullary hyperintensity signals on T2-weighted images at the C1-C2 level. Posterior stabilization was performed for all patients by using ITFN. RESULTS: The mean Nurick score improved from 2.3 before surgery to 0.7 at the time of follow-up. The mean follow-up period was 34.7 months (range, 12-65 mo). According to Odom's criteria, outcomes were as follows: excellent, 47%; good, 37%; fair, 11%; and poor, 5%. All patients with preoperative neck pain had symptom relief or improvement, with all of these patients having more than 83.7% improvement in visual analogue scale scores. The mean preoperative space available for cord value of 9.3 mm improved to 17.7 mm. Solid fusion and reduction of atlantoaxial dislocation were achieved in every patient without screw failure. Sixty screws were placed in 19 patients. Two C2 polyaxial screws in 2 patients and 1 transarticular screw in 1 patient slightly penetrated the transverse foramen with no vascular injury and clinical sequelae. CONCLUSION: ITFN is a safe, accurate, and effective tool for screw placement in patients with symptomatic os odontoideum.

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.

BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.