Objective:To evaluate the effect of ultrasound contrast agent on expression of plasmid in intervertebral disc of Sprague-Dawley rats.Methods:Forty adult Sprague-Dawley rats were studied.The rats were randomly divided into 4 groups.Two different reporter plasmid DNA encoding green fluorescent protein(GFP) and firefly luciferase were used.Plasmid DNA was mixed with ultrasonography contrast agent(microbubbles) and injected into coccygeal intervertebral discs of Sprague-Dawley rats.The ultrasound was irradiated on the surface of injected discs.Rats were killed 7 days after gene transduction.Harvested nucleus pulposus tissues were used to evaluate gene expression.The intact discs were used as a control.Results:Significant luciferase activity was observed in group 4;less in the other groups and none in the control.Conclusion:Ultrasound with microbubble contrast agent induced efficient gene transfer to interverbetebral disc of rats after local injection of plasmid.

Objective To evaluate the feasibility, safety and efficacy of percutaneous vertebroplasty (PVP) for osteoporotic compression fracture of the upper thoracic spine.Methods The study enrolled 20 patients with osteoporotic compression fracture in 25 upper thoracic segments.The subjects (5 males and 15 females) aged at (71.0 ± 10.8) years (range, 57-89 years).Fracture occurred in 2 T1, 3 T2,5 T3 and 15 T4 segments.The subjects were submitted to puncture process via unilateral extrapedicular approach.Operation time, volume of infused bone cement, X-ray images and CT scan were recorded after operation.Visual analogue score (VAS), mobility score and Oswestry disability index (ODI) were assessed after operation.Results The procedure was successfully accomplished in all patients.Mean operation time was (39.7 ± 10.6)min.Infusion volume of bone cement was 2.0-6.0 ml [(3.3 ± 1.5)ml].Eighteen patients were available to the follow-up of 5.5-18 months [(7.6 ± 2.7) months].Three patients (15％) were associated with cement leakage into the epidural (n =1), paravertebral soft tissues (n =1) and disc (n =1) but remained asymptomatic.One patient (5％) had new fracture at the non-adjacent and non-operative segments within 15 days, and had no recurrence after PVP.No other serious complications such as rib fracture, pneumothorax, pulmonary embolism, vascular injury, spinal injury and infection were found.VAS, mobility score and ODI improved at 3 d, 1 month, 3 months and final follow-up compared to those at 1 d pre-operation (P ＜0.O1).Conclusions PVP is a safe and effective treatment for upper thoracic osteoporotic compression fracture, which is associated with few complications,reduced pain and improved mobility as well as quality of life.Rational surgical position and puncture approach are beneficial to a successful surgery.

ObjectiveTo discuss the feasibility and safety of anterior pedicle screw (APS) fixation in treatment of lower cervical spine injuries.MethodsA total of 10 patients with lower cervical spine injuries were treated with APS fixation.All the patients received preoperative cervical CT scans,and then three-dimensional model was reconstructed by using Mimics software to measure the screw placement parameters (insertion point,screw placement angle,screw length and diameter).All APS fixations were performed through anterior cervical approach,and then centrums antetheca and bilateral outer edges were exposed to distinguish the vertebral end plates.Screw insertion was strictly operated under the fluoroscopic assistance and preoperative screw placement parameters.The postoperative efficacy of APS fixation was evaluated by radiologist and other orthopedist via anteroposterior and lateral radiation,CT scan,three-dimensional model reconstruction and MRI.A follow-up was carried out at 1,3,6 and 12 months after operation.ResultsExcept for one screw for C4 and one for C7,another 24 crews for C3-C7 were successfully inserted.Postoperative CT scan demonstrated four screws breaking the outer vertebral wall.Except for one patient suddenly died from acute myocardial infarction one week after operation,the other nine patients received follow-up.Of three trauma patients,one patient at Grade A did not get improvement but with no aggravation and two achieved improvement for 2-3 grades according to Frankel grade.Among six non-trauma patients,spinal function score by JOA was averagely elevated to 13.4 points,with improvement rate of 60.7％ according to Hirabayashi method.There were no serious complications except for two patients of dysphagia among the patients who were followed up. Conclusions APS fixation is feasible for lower cervical spine injuries.The keys to successful screw insertion are preoperative measurement of individualized screw insertion parameters and appropriate application of intraoperative fluoroscope technique.

To evaluate the feasibility of magnetic navigation ultrasonography system in guiding the puncture of percutaneous posterior endoscopic cervical discectomy ( PPECD ) . Methods T he cervical CT data of 6 patients with cervical spondylosis were used to made 3D printing model ,then the localized puncture of the model was guided by the magnetic navigation ultrasonography system ,1‐mm‐slice transection CT scans were obtained to confirm the placement of the needle tips after puncture . T he total puncture time and the distance between the pinpoint in the lateral and longitudinal directions from the ＂V point＂were recorded . Results All the 36 puncture operations accurately located the target segment without penetrating the spinal canal . T he average lateral distance of the needle tip from the ＂V point＂was 2 .88 mm ( 0－7 .12 mm ) ,meanw hile the average longitudinal distance was 1 .64 mm ( 0 －4 .45 mm ) ,and the the w hole process took 3 .72 min( 2 .42－5 .20 min) . T hirty‐three of 36 points were in the circle with ＂V point＂as the center and 5mm as the radius ,puncture success rate was 91% . Conclusions T he puncture model established in this study can be used as a teaching tool ,magnetic navigation ultrasonography system has successfully guided the posterior cervical intervertebral disc puncture on the model ,and there is no radiation exposure during the operation process ,which has a promising clinical application prospect .

ObjectiveThe study aimed to evaluate the measurement uncertainty in the determination of five cacaine anesthetics and their metabolites residues by high-performance liquid chromatography-tandem mass spectrometry （LC-MS/MS）. MethodsThrough the establishment of mathematical model， the sources of uncertainty were analyzed， and various components were quantified and synthesized to evaluate the influence of the uncertainty components on the measurement results． ResultsThe uncertainties of the experiments were mainly derived from calibration curve fitting， sample pretreatment， recovery rate， standard solution preparation and measurement repeatability. Furthermore， the expanded uncertainty related to the content in shrimp （k=2） was 1.18 μg‧kg^-1 at 8.68 μg‧kg^-1 for tricaine methanesulfonate （MS-222）， 1.28 μg‧kg^-1 at 9.11 μg‧kg^-1 for benzocaine， 13.5 μg‧kg^-1 at 91.4 μg‧kg^-1 for 4-aminobenzoic acid， 12.2 μg‧kg^-1 at 91.0 μg‧kg^-1 for p-acetylamino benzoic acid， and 11.3 μg‧kg^-1 at 95.3 μg‧kg^-1 for 3-aminobenzoic acid， respectively. ConclusionThis method is suitable for the uncertainty analysis of cacaine anesthetics and their metabolites determination in aquatic products by LC-MS/MS， and can provide scientific and reliable basis for the measurement accuracy.

【Objective】 To investigate the feasibility of full-endoscopic posterolateral odontoidectomy through morphological analysis and cadaver specimen surgery. 【Methods】 We collected the DICOM data of 20 normal cervical CT patients （10 males and 10 females） from the PACS Image Library of our hospital. The Mimics software was used for cervical CT reconstruction and anatomical measurements were made to measure the maximum sagittal diameter， coronal diameter and height of the odontoid process. The C1 lateral mass could provide the maximum working height and width of endoscopic operation with a diameter of 7 mm， as well as the angle between the anchor point of C1 lateral mass and the notch on both sides of the odontoid process. The feasibility of endoscopic surgery was analyzed based on the measured data. The fresh frozen corpse was used for the operation in prone position under the guidance of C-arm. Kirschner wire was anchored at the midpoint of the lower surface of the C1 lateral mass. Part of the C1 lateral mass was removed by the grinding drill and endoscopic tools， and then the odontoid process and adjacent ligaments were removed. 【Results】 The maximum sagittal diameter， coronal diameter and height of the odontoid process were （11.73±0.74）mm， （10.97±0.71）mm and （14.51±0.91）mm， respectively. The working height and width of the C1 lateral mass were （13.53±0.57）mm and （10.00±1.27）mm， respectively. The angle between the anchor point and the double-edge notch of the odontoid process was （28.3±3.1）°， with no statistical difference between the male and female patients （P>0.05）. All the measurements met the requirements of 7 mm endoscopic implantation and surgical operation， and the space for swing could be provided for complete or partial removal of the odontoid process to meet the requirements of ventral spinal decompression. In cadaver surgery， a fully endoscopic posterolateral approach enabled complete removal of the odontoid process by grinding part of the C1 lateral mass. Postoperative cervical CT confirmed that the odontoid process had been completely resected， and there were no signs of dural sac or vertebral artery injury. 【Conclusion】 The odontoid process can be completely resected through a posterolateral endoscopic approach via the lateral mass approach of C1， providing a new surgical method for clinical odontoidectomy to decompress the spinal cord in craniovertebral junction.