The validity of moral education is the emphases and difficulty that current research and academic studies focus on.Taken the concept of validity as the basic point,this article analyzes the deep-seated reason why the medical ethics education loses its validity and discusses the rules to realize the validity of the medical ethics education from the aspects that the medical ethics education should return to real life,adapt to psychology laws and penetrate through the clinical stage.

Objective To construct a detailed, 3-dimensional, anatomically accurate finite element (FE) model of lumbar L4-L5 segment from CT data with a new kind of computer aided design (CAD) method. Methods A modified "no-seed region segmentation" was done to extract the interest region in the CT scan images and produce a binary image. "Best cross-section planes" accounting for the preferential direction dictated by lumbar spine were placed on the initial iso-surface model, forming a "non-regular piecewise subspace". This subspace and the embedded iso-surface mode were transformed by local affine transforms to a "regular subspace", in which a surface mesh of high quality was generated quickly. Finally a reverse transform procedure was employed to recover the shape feature of the lumbar surface mesh of lumbar L4-L5 in the original 3-dimensional space, which was then imported into ANSYS for the 3-dimensional FE mesh construction. Results All complicated anatomical features of the L4-L5 segment were explicitly represented in the unprecedented finite element model. The predicted results for compression, flexion and extension correlated well with experimental data under similar loading configurations. Conclusion The presented CAD method containing advanced algorithm implements fast and accurate simulation of such complicated geometry with fine mesh representation for lumbar FE analysis.

Objective Retrospective study and report on cases of "symptomatic facet of residual bone mass" caused by percutaneous transforaminal endoscopic discectomy (PTED),to analysis of its causes and revision strategies.Methods Seven cases of "symptomatic facet of residual bone mass" after PTED were found in six medical centers from July 2015 to November 2017.Weintroduced the course of diagnosis and treatment,to analysis of the causes,clinical features and revision strategies of the rare complication.Results Seven patients came from different medical centers (2 cases in Ningbo No.6 Hospital and 1 case in each of the other medical centers).The average age of the subject is 67.29±9.64 years (range from 57-83 years).Among them there were 1 male and 6 female.PTED was performed for all cases with lumbar disc herniation or stenosis.The operative segments were 1 of L2,3,2 of L3,4,3 of L4,5,1 of L5S1.Symptoms occurred immediately after surgery in all cases except one after a week of operation and another one month later.Two cases were appeared symptom of contralateral irritation,and the rest were aggravated by the original symptoms.Two cerebrospinal fluid leakage caused by bone mass piercing the dural sac.The bone mass compressed the nerve root and caused 1 case of lower limb muscle weakness.Foraminoplasty was performed during PTED in all patients.After CT scan,5 cases of bone mass were found on the same side of operation,and 2 cases were in the contralateral side.The shortest time for revision was 2 days and the longest 3 months.After conservative treatment,the symptoms were relieved in only one case.Revision surgeries were performed for all the other 6 cases,2 with microendoscopic discectomy (MED),1 mobile microendoscopic discectomy (MMED),1 small incision operation,1 PTED and 1 with minimal invasive surgery of transforaminal lumbar intervertebral fusion (MIS-TLIF).The VAS scores of low back pain and leg pain was significantly relieved from 8.67±0.52 to 1.50±0.55.Conclusion FTED may lead to residual bone mass in lumbar foraminoplasty.The penetration of the bone mass block into the spinal canal can cause the compression symptoms of the corresponding segment.The patients showed the corresponding spinal canal stenosis and nerve root irritation symptoms.A revision operation is required to remove the oppressed bone mass to relieve the symptoms as soon as possible if the conservative treatment not effective.

Objective To explore the clinical effects of C2 dome-like expansive laminoplasty and C2 expansive opendoor laminoplasty in upper cervical(involve or above C2 segment) ossification of the posterior longitudinal ligament.Methods All of 39 patients (22 males and 17 females) withcervical ossification of the posterior longitudinal ligament up to C2 which causedcompression symptoms were operated with posterior cervical surgery in ourhospital from January 2013 to June 2017.The average age was 55.74+7.91 years old,ranging from 39 to 71 years.Among these patients,21 patients underwent C2 domelike expansive laminoplasty and 18 underwent C2 expansive open-door laminoplasty,the patients in both groups underwent the C3-C7 expansive open-door laminoplasty.The preoperative and postoperative Neck Disability Index (NDI),Japanese Orthopedic Association (JOA) score,the xisual analog scale(VAS) and the space available for the spinal cord (SAC) of C2 segment in X-ray were measured and statistically analyzed.Results All patients were followed up,the follow-up time was from 15 to 63 months (mean 42.3±17.7 months).There was no significant difference in the general condition,NDI,JOA score and JOA score improvement rate between preoperative and postoperative follow-up in 2 groups.There were significant differences in the NDI,JOA,VAS and SAC between preoperative and postoperative follow-up in 2 groups.The VAS score in C2 dome-like expansive laminoplasty group 1.52± 1.2 was significantly lower than that in C2 expansive open-door laminoplasty group 2.06±0.87(t=-2.23,P＜0.05),while the SAC in C2 expansive open-door laminoplasty group 14.11±1.023 was significantly higher than that in C2 dome-like expansive laminoplasty group 1 L86± 1.014(t=-6.89,P＜0.05).No failure of internal fixation or recurrent compression was found during follow-up.Conclusion For patients with ossification of posterior longitudinal ligament up to C2 or higher level,both C2 dome-like expansive laminoplasty and C2 expansive open-door laminoplasty can achieve good results.The SAC in C2 expansive open-door laminoplastygroup was superior to that in C2 dome-like expansive laminoplasty group,while the postoperative pain was more obvious.There was no significant difference in postoperative neurological recovery between the two groups.Using C2 dome-like expansive laminoplasty could reduce postoperative axial pain than the C2 expansive open-door laminoplasty surgery.For patients withossified tissue in the spinal canal,which occupies more than 50％ of the sagittal diameter of the spinal canal,or with developmental spinal stenosis,C2 expansive open-door laminoplasty may berecommend to get more adequate decompression.