Objective To measure the curvatures of the distolingual root canals of permanent mandibular first molars by cone-beam computed tomography (CBCT). Methods The CBCT was used to collect 230 cases of mandibular first molar distalingual root from 513 patients. The images were created by 3-D reconstruction based on the BECT data. Images were analyzed by NNT image analysis software. Each tooth was captured in clinical (CV) and proximal view (PV) image, and measured by the Schneider method. Results The average curvature of the distallingual canal was (13.27 ± 8.57)° in CV, and (30.96 ± 11.63)° in PV. Most of the distallingual root in the buccolingual view was mild bending or moderate bending , and the proximal view was severe bending. The distal lingual root bending was the most common in the crown third of the root , next in the apical third of the root, in the middle third of the root. Conclusion CBCT is an effective tool for the detection of additional distolingual roots and is a valuable aid for dentists in root canal treatment.

BACKGROUND : After femoral neck fracture, incidences of ischemic necrosis and bone non-healing are closely related to biomechanical characteristics of internal fixation devices. Compression stress can improve fracture healing, tension force can delay fracture healing, and shear stress can inhibit fracture healing. How to relieve shear stress and expand compression stress is of significance for theories and clinical applications.OBJECTIVE: To compare the biomechanical characteristics of the two geometric configurations of three cannulated compression screws in the fixation for femoral neck fracture and to provide a theoretical foundation in the treatment of femoral neck fracture.DESIGN : Observational contrast study.SETTING: Department of Orthopaedics, the 251 Hospital of Chinese PLA; Department of Orthopaedics, the Third Hospital, Hebei Medical University.PARTICIPANTS: The experiment was carried out in the Hebei Orthopaedic Institute from November 2002 to March 2003. Five cadavers including 4 males and 1 female with similar bone mineral density (BMD) were provided by Department of Anatomy, Hebei Medical University. X-ray photographs proved that all the cadavers did not have rheumatism, tuberculosis, tumor, fracture or deformity.METHODS: Ten femurs were randomly divided into inverted and upright isosceles triangle with 5 in each group. Femur samples with femoral neck fracture were fixed with three cannulated screws and measured with the biomechanical machine (CSS-44020, made in Changchun Experimental Researching Institute, provided by Hebei Orthopaedics Institute). The compression strength, torsibility and the maximal vertical loading were compared between the two configurations of screws.MAIN OUTCOME MEASURES:①Displacement of femoral head at 600 N and 750 N during torsibility test; ②torque-moment at 2°and 4°during torsibility test;③load during maximal vertical loading test.CONCLUSION: The effect of three cannulated compression screws configured as an inverted isosceles triangle on the treatment of femoral neck fracture is superior to that of three cannulated compression screws as an upright isosceles triangle.

Objective To evaluate the clinical outcomes of modified eggshell technique through posterior approach for the treatment of hard thoracic disc herniation. Methods From January 2006 to June 2009, 22 patients admitted for hard thoracic disc herniation were reviewed, including 13 males and 9 females, with an average age of 49.5 years (range, 33-69). The courses of disease were 11 months on the average (range, 3-18 ). The lesions located in T8-9 for 4 cases, T9-10 for 9, T10-11 for 7, T11-12 for 2. Each of the patients underwent X-ray, CT scanning and MRI examination before surgery. There were 16 cases of central type, and 6 cases of paracentral type. All patients were treated surgically by modified eggshell technique via posterior approach. Results The mean operative time was 210 min (range, 180-300 min), with a mean blood loss of 860 ml (range, 600-1200 ml). All surgeries were performed successfully without neurological symptoms aggravation. Surgical complications included dural laceration in 2 cases, both dural lacerations were repaired intraoperatively, epidural hematoma in 1 case with lower extremity neurological symptoms, full neurologic recovery was observed after surgical removal of the hematoma. All patients were followed up for average 27.5 months (range, 12-54). The mean JOA score increased from 3.36±1.79 before operation to 7.45±2.99 after the operation at 12 months follow up, and the mean improvement rate of neurological status was 58.3%±30.7%. There was significant difference in JOA score before and after surgery(t=10. 12,P＜0.01 ).The results of 14 cases were ranked as good, 6 as fair, 2 as unchanged, and none as worsened. All cases obtained bony fusion without instrument failure. Conclusion Modified eggshell technique enable ventral and dorsal spinal decompression from the posterior approach in cases of hard thoracic disc herniation, with reduction of the rate of postoperative paralysis.

BACKGROUND: Degenerative lumbar spinal stenosis could be treated by laminectomy internal fixation placement,unilateral or bilateral decompression,posterior laminectomy and so on.However,whether laminectomy internal fixation placement can be used remains unclear.OBJECTIVE: To evaluate the efficacy of interbody fusion cage implantation of pedicle screw fixation,in combination with posterior lumbar laminectomy,bilateral resection and decompression of the inferior articular process,autologous facet joint bone transplantation in the treatment of degenerative lumbar spinal stenosis.METHODS: A total of 41 patients of degenerative lumbar spinal stenosis,who failed after 3 months of conservative therapy,including 23 males and 18 females,at a mean of 60.3 years,Received posterior lumbar laminectomy,bilateral inferior articular process resection and decompression,autologous facet joint bone and cage interbody fusion implant pedicle fixation.They were followed up for 24 months,preoperative and postoperative Japanese Orthopedic Association(JOA)score evaluations were performed to assess the therapeutic efficacy of the patients,radiological examination was done to investigate the graft fusion and vertebral stability of surgical segments in patients.RESULTS AND CONCLUSION: During the follow-up,JOA score significantly increased compared with the preoperative score(P＜0.01)and clinical excellence rate was 90%; 40 cases obtained bony fusion,with a fusion rate of 98%,1 patient exhibited signs of lumbar instability.There was no loosening,fracture and other complications after internal fixation,but 2 cases appeared dural tear,1 case pedicle position deviation,1 case pseudoarticulation formation.The results suggest that the posterior lumbar laminectomy,bilateral inferior articular process resection and decompression,autogenous facet joint bone and cage interbody fusion implanted pedicle screw fixation show good clinical effects for the treatment of degenerative lumbar spinal stenosis.

Objective To explore the effect of problem-based learning method in traditional Chinese internal medicine teaching. Methods 58 students enrolled in the major of integrated traditional Chinese and western medicine in class C at the Beijing University of Chinese medicine were arranged to receive PBL(test group)or traditional teaching methods(control group)in 2 courses and complete 116 questionnaires. The teaching outcomes were evaluated by questionnaire and individual interviews. Results Compared with controls,students receiving PBL performed significantly better in terms of active classroom atmosphere, broadening their knowledge, and improving teamwork ability(χ2 were 7.16, 4.07, 4.09, P<0.05). Conclusion The PBL strategy has the advantage than the traditional teaching methods in traditional Chinese internal medicine teaching.

Nanoliposomes are considered to be the most successful nanoparticle drug delivery system, but their fate in vivo has not been fully understood due to lack of reliable bioanalytical methods, which seriously limits the development of liposomal drugs. Hence, an overview of currently used bioanalytical methods is imperative to lay the groundwork for the need of developing a bioanalytical method for liposome measurements in vivo. Currently, major analytical methods for nanoliposomes measurement in vivo include fluorescence labeling, radiolabeling, magnetic resonance imaging (MRI), mass spectrometry and computed tomography.In this review, these bioanalytical methods are summarized, and the advantages and disadvantages of each are discussed. We provide insights into the applicability and limitations of these analytical methods in the application of nanoliposomes measurement in vivo, and highlight the recent development of instrumental analysis techniques. The review is devoted to providing a comprehensive overview of the investigation of nanoliposomes design and associated fate in vivo, promoting the development of bioanalytical techniques for nanoliposomes measurement, and understanding the pharmacokinetic behavior, effectiveness and potential toxicity of nanoliposomes in vivo.

Objective:To evaluate the clinical efficacy of minimally invasive treatment of Fraser type Ⅱ floating knee by homeopathic reduction.Methods:From November 2016 to July 2018, 7 patients with Fraser type Ⅱ floating knee were treated by homeopathic reduction and minimally invasive surgery at Trauma Emergency Center, The Third Hospital of Hebei Medical University. They were 5 males and 2 females, aged from 30 to 82 years (average, 52 years). They all suffered from tibial plateau fracture complicated with floating knee, with 5 cases of Fraser type ⅡA (tibial plateau fracture complicated with femoral shaft fracture) and 2 cases of Fraser type ⅡC (tibial plateau fracture complicated with femoral condyle fracture). The femoral and tibial plateau fractures were reduced with a bidirectional traction reduction device, followed by minimally invasive implantation of internal fixators. The operation time, length of a single incision, blood loss and fluoroscopic frequency were recorded. The anteroposterior and lateral X-ray films of the lower limb were taken and fracture healing time was recorded during follow-up. The function of knee joint was evaluated by Hospital for Special Surgery (HSS) scoring system at the last follow-up.Results:For the 7 patients, operation time averaged 87.2 min, length of a single incision 2.8 cm, blood loss 471 mL, and fluoroscopy frequency 37 times. The postoperative X-ray films showed fine alignment and force line and smooth articular surface in all patients. All the incisions healed by grade A. The follow-up time for 7 patients ranged from 12 to 21 months (average, 15.6 months). All the fractures healed after an average time of 12.8 weeks. The HSS scores at the last follow-up showed that 6 cases were excellent and one was good.Conclusion:The fractures of the femur side and of the tibia side can be treated separately by closed reduction and internal fixation using a homeopathic bidirectional traction reduction device so as to obtain better knee joint function.

The purpose of this study was to compare the biomechanical stability obtained by using our technique featured an anatomical plate and compression bolts versus that of the conventional anatomic plate and cancellous screws in the fixation of intraarticular calcaneal fractures. Eighteen fresh frozen lower limbs of cadavers were used to create a reproductive Sanders type-III calcaneal fracture model by using osteotomy. The calcaneus fractures were randomly selected to be fixed either using our anatomical plate and compression bolts or conventional anatomic plate and cancellous screws. Reduction of fracture was evaluated through X radiographs. Each calcaneus was successively loaded at a frequency of 1 Hz for 1000 cycles through the talus using an increasing axial force 20 N to 200 N and 20 N to 700 N, representing the partial weight bearing and full weight bearing, respectively, and then the specimens were loaded to failure. Data extracted from the mechanical testing machine were recorded and used to test for difference in the results with the Wilcoxon signed rank test. No significant difference was found between our fixation technique and conventional technique in displacement during 20-200 N cyclic loading (P=0.06), while the anatomical plate and compression bolts showed a great lower irreversible deformation during 20-700 N cyclic loading (P=0.008). The load achieved at loss of fixation of the constructs for the two groups had significant difference: anatomic plate and compression bolts at 3839.6±152.4 N and anatomic plate and cancellous screws at 3087.3±58.9 N (P=0.008). There was no significant difference between the ultimate displacements. Our technique featured anatomical plate and compression bolts for calcaneus fracture fixation was demonstrated to provide biomechanical stability as good as or better than the conventional anatomic plate and cancellous screws under the axial loading. The study supports the mechanical viability of using our plate and compression bolts for the fixation of calcaneal fracture.

Objective To explore value of trephine in pedicle subtraction osteotomy (PSO) for old thoracolumbar compression fracture with kyphotic deformity.Methods Thirty seven patients who underwent surgical treatment for old thoracolumbar kyphotic deformity in our hospital from February 2005 to February 2010 were retrospectively reviewed.Among them,21 patients underwent conventional PSO and 16 patients underwent PSO with trephine.In conventional PSO group,there were 14 males and 7 females,the average age was 55.6±3.7 years and the mean Cobb angle was 45.3°±4.6°.In PSO with trephine group,there were 11 males and 5 females,the average age was 53.3±4.2 years and the mean Cobb angle was 47.6°±5.9°.Results All patients were successfully followed up.The duration of follow-up ranged from 12 to 22 months in conventional PSO group,while 13 to 20 months in PSO with trephine group.The operation time,blood loss,amount of blood transfusion were 224±45 min,1043±234 ml,876±300 ml respectively in conventional PSO group,while 180±31 min,785±163 ml,500±230 ml in PSO with trephine group.Immediately after operation,correction rate of Cobb angle was 91.4％ in conventional PSO group and 90.9％ in PSO with trephine group.At final follow-up,the correction of Cobb angle lost 5.8％ in conventional PSO group and 6.2％ in PSO with trephine group.The improvement rate of JOA score was 81.1％ in conventional PSO group and 83.7％ in PSO with trephine group.The VAS score decreased 7.7±1.1 in conventional PSO group and 7.8±0.8 in PSO with trephine group.One patient in conventional PSO group experienced saddle numbness immediately after operation,which alleviated at final follow up.All patients achieved bony fusion at final follow up.No infection,screw loosening or breakage occurred in both groups.Conclusion The use of trephine in PSO for old thoracolumbar compression fracture with kyphotic deformity can reduce operation time,blood loss and improve efficiency of osteotomy.

Objective To investigate the efficacy and safety of the resection of cervical posterior longitudinal ligament (PLL) in Bryan cervical disc arthroplasty. Methods Thirty-one patients underwent Bryan cervical disc implantation only in one level from August 2006 to January 2009 were investigated in this study. Cervical PLL was preserved in 14 patients, but not in other 17 patients. The clinical (JOA score,VAS score for neck and arm pain) and radiographic parameters (the FSU angle, ROM and diameter of the spinal cord) were compared between the two groups. Results No differences were found in terms of age, affected segment, gender, follow-up period, operation time and blood loss between the two groups. Patients underwent removal of cervical PLL were significantly superior to those underwent reservation of cervical PLL in term of clinical outcomes. There were no differences between the two groups with regard to the increase of FSU angle and ROM. However, the diameter of the spinal cord had a significant increase in patients underwent removal of cervical PLL. No severe complication was found in the two groups. Conclusion Removal of the cervical PLL is beneficial for the clinical outcomes and does not have an impact on the angle and ROM of the affected segment. The procedure is safe and feasible.