Objective To investigate the correlation between intra-operative estimated blood loss (EBL) and bone mineral density (BMD) during minimally invasive posterior lumbar interbody fusio,n (PLIF).Methods In this retrospective case control study,61 consecutive patients suffering from mono-segment low back disorders were treated by minimally invasive PLIF from 2005 to 2010.The patients' parameters including age,gender,operation time (OT),BMD,EBL,prothrombin time were collected.According to BMD of the lumbar spine,all the patients were divided into two groups: the normal group and the osteopenia group.The differences of the EBL and other parameters between the two groups were analyzed by student's t test and Pearson's Chi-square test.Besides,the correlation between intra-operative EBL and each of the other parameters except for gender were analyzed among all the patients.To detect the relationship between intra-operative EBL and gender,patients were divided by gender and the intra-operative EBL of two groups were examined by student's t test.Finally,a probable model about intra-operative EBL and the other parameters was proposed using stepwise linear regression analysis.Results The average intra-operative EBL of the normal group and the osteopenia group were (346.41±199.53) ml and (552.62±300.21) ml,respectively.The difference was significant.However,the other parameters including post-operative EBL had no significant differences between two groups.A negative correlation between intra-operative EBL and BMD (r=-0.37,P=0.035)and a positive correlation between intra-operative EBL and OT (r=0.34,P=0.008) were found.But none of the other parameters was correlated with intra-operative EBL.The similar result was observed by the stepwise linear regression analysis.Intra-operative EBL was influenced by BMD and OT under the control of this research,and the relationship might be formulated with the equation,EBL=-0.63×BMD+1.46×OT.Conclusion BMD should be considered an important predictor of intra-operative EBL in PLIF.

With the aging of population, the incidence of osteoporosis and intervertebral disc degeneration increased remarkably.As a consisting part of spine, vertebrae play important roles in spinal diseases.The microstructure of vertebrae is closely associated with not only its biomechanical properties, but also its adjacent intervertebral discs.A detailed understanding of vertebrae's microstructure can help us understand the initial mechanism, progression and prognosis of vertebrae and its adjacent discs' diseases.On the other hand, traditional examinations are less effective in detecting vertebrae's microstructure.Being a noninvasive, high-resolution and bony-sensitive neo-technology, Micro-CT has obvious advantages in detecting vertebrae's microstructure.Many researches have reported the usage of Micro-CT in reveling microstructures while they also raised problems.Thus, herein we searched the related information of vertebrae's microstructure scanning with Micro-CT, explained its basic mechanism, reviewed its progress in technology and arithmetic, and concluded the latest developments.Depending on the microstructure revealed by Micro-CT, achievements in biomechanical properties of vertebrae and intervertebral disc degeneration have been made,and related problems have been summarized.Also, new applications of Micro-CT in spinal diseases are discussed for acquiring reasonable clinical data in the future.

Objective To determine the correlation between the Modic degeneration of lumbar endplate on MRI and the pain provocation or degeneration of lumbar intervertebral discs observed on CT discography. Methods One hundred and twenty lumbar intervertebral discs (40 L3-4, 40 L4-5, 40 L5S1 intervertebral discs) of 40 patients among 45 patients were examined. 120 intervertebral discs underwent discography guided by CT scan, according to Dallas Discography Description system, degeneration of lumbar intervertebral disc were divided into 0-3 grade, and pain provocation were graded into negative, indifferent and positive. On the basis of Modic classification system of the lumbar endplate changes and Pearce classification system of the degeneration of lumbar intervertebral disc, the lumbar endplate changes were divided into 0-3 grade, the degeneration of lumbar intervertebral disc were graded into Ⅰ-Ⅴ. All the results were analysed by Chi-Square test for the correlations. Results There was positive correlation between pain provocation test and the lumbar endplate Modic degeneration; There was a positive correlation between the Modic degeneration of lumbar endplate and the degeneration of lumbar intervertebral disc and so is the relation between the CT discography and MRI on discs. Conclusion There is positive correlation between pain provocation test and the Modic degeneration of lumbar endplate, it suggest the endplate might be one of the sources of low back pain. There is a positive correlation between the Modic degeneration of lumbar endplate and the degeneration of lumbar intervertebral disc.

Objective To evaluate the diagnostic value of the nerve root sedimentation sign for lumbar spinal stenosis and improve morphological classification.Methods This is a retrospective radiologic study.From November 2012 to November 2013,511 patients who carried out MR examination due to backache together with intermittent claudication were selected.Cross-section MRI images at the narrowest layer of canalis spinalis were chosen.The patients were further divided into 7 groups,A1,A2,A3,A4,B,C,and D based on Schizas.The dural sac cross-sectional area (DSCA) of each group was measured.The groups without difference were merged.A new method to grade nerve root sedimentation was developed.Then,the correlation and consistency of nerve root sedimentation dichotomy,Schizas classification,new nerve root sedimentation classification and DSCA classification were compared.The differences of patients' Oswestry disability index (ODI) which adopted new classification method were compared.Results Results show there are no statistical significance between groups A1 and A2,groups A4 and B,or groups C and D in DSCA.After the merger,new nerve root sedimentation classification includes negative,a,b,and c.The correlation between nerve root sedimentation dichotomy and DSCA method is rs=0.579,and the consistency is κ=0.254.The correlation between new nerve root sedimentation classification method and DSCA method is rs=0.722,and the consistency is κ=0.381.The scores improve compared with the first two classification methods.ODI score difference of each group which adopted new nerve root sedimentation classification method has statistical signiftcance (F=17.972,P=0.000).Pairwise comparison shows only group c differs significantly from other groups (P＜0.05).Conclusion The new nerve root sedimentation classification method is more effective than nerve root sedimentation dichotomy and Schizas grading.It reflects the severity degree of patients'clinical symptoms to some extent.

ObjectiveTo observe the morphological features of the basivertebral foramen (BF) in thoracolumbar (T12,L1,L2 and L3).MethodsA total of 36 health adults were underwent multi-slice CT thin slice scans and three-dimensional reconstruction.In the horizontal and sagittal CT reconstruction images,BF weight (BFW),BF depth (BFD),BF high (BFH),BF relative to the body weight (BFWr),BF relative to the body depth (BFDr),and BF relative to the body high (BFHr),were measured.The distance between the BF and each side in the horizontal and sagittal CT images were also measured.The correlation between the measured parameters of BF and the gender,age,body mass index(BMI) were analyzed statistically.Results 81％ BF was triangular or trapezoid.There was a bone interval within 6％ BF.In the same level in 36 cases,the maximum of BFW,BFD and BFH were approximately 1/3 vertebral body in the same plane.The average BFW,BFD and BFH were approximately 25％ vertebral body in the same plane.In all four levels,the distance from the BF to the cranial endplate was shorter than to the caudal endplate (P＜O.05).The mean BFW,BFH,BFWr,BFHr in different levels were no significant difference(P＞0.05).The mean BFD and BFDr in L3,however,were greater than other levels.There were no significant correlations among gender and BFW,BFWr,BFD,BFDr,BFH,BFHr.There was a correlation between the age and L1BFHr and L2BFHr,and a correlation between BMI and L1BFH,L2BFW,L3BFH and L3BFHr.ConclusionThere was a BF in all specimens.The most common appearance of BF was triangular or trapezoid.BF was closer to the cranial endplate in all four levels in the sagittal CT images.Variations of BF were significantly different in individuals.

Objective To retrospectively investigate diagnostic and therapeutic value of intradiscal steroid injection in patients with discogenic low back pain combined with radial fissure of annulus fibrosis.Methods Totally 120 patients who had undergone CT guided intervertebral discography and steroid injections,including 72 males and 48 females,aged from 25 to 60 years (average,48 years),were recruited to this study.According to Dallas discography description system,7 cases were rated as grade 0,36 grade 1,48grade 2,and 29 grade 3.The Visual Analogue Scale (VAS) and Roland Morris Disability Questionnaire (RMDQ) were used to evaluate clinical effect at 2 weeks,2 months,6 months,12 months and 24 months postoperatively.Results Most of patients who underwent steroid injection in single highly suspect diseased disc claimed significant symptom improvement.There were statistically significant differences between pre- and post-operative VAS and RMDQ.The clinical effect in grade 3 group was better than those in grade 1 and grade 2 groups,and the differences were significant.Patients with severe disc disruption (grade 3) had a lower recurrence rate of low back pain compared with other patients.Conclusion Intradiseal steroid injection not only can significantly relieve discogenic low back pain,but also can benefit diagnosis of discogenic low back pain,especially in patients who fail to reproduce concordant pain on discography.For patients with severe rupture of the annulus fibrosus,the relief of discogenic low back pain is more significant.

Objective To ev aluate clinical results of selective anterior corpectomy combined with segmental discectomv and fusion for multilevel cervical myelopathv andits related factors.Methods Twenty-five patients of multilevel cervical myelopathv with 3 or 4 consecutive segments were treated with selective anterior corpectomy combinedwith segmental discectomy and fusion.The clinical results were evaluated by the parameters including improvement of Japanese Orthopaedic Association (JOA)score postoperatively,fusion rate,and the degree of spinal canal decompression and range of motion of the cervical spine.Results JOA score were improved from 9.5±1.3 pre-operatively to 13.8±0.8(P＜0.01)6 months post operation and 1 3.6±0.9(P＜0.05)atthe final follow-up.Bony fusion was verified by X-ray and 3D-CT scan 1 2 months post operation and final follow-up.Moreover,the degree of decompression of the spinal canal was also remarkable.The range of motion of the cervical spine after operation decreased significantly(P＜0.05).Conclusion Selective anterior corpectomy combined with segmental discectomy and fusion was an alternative choice for the surgical treatment of multilevel cervical myelopathy.

Objective To evaluate the distribution of Schmorl's nodes (SN) in patients with low back pain or radiculopathy,and to analyze the correlation between SN and degeneration of lumbar intervertebral discs.Methods In 2012,1024 patients with low back pain or sciatica were examined by magnetic resonance (MR) scan and plain film.There were 448 males and 576 females,with an average age of (54.3 ± 12.7) years (range,22-90).The features distribution of SN in lumbar endplate on age,sex,segment and the type and grade of intervertebral disc degeneration were analyzed retrospectively.Results Among 5120 lumbar intervertebral segments of the 1024 patients,295 (28.8％) cases and 532 (5.2％) endplates were involved with SN,302 located in the cranial and 230 in the caudal endplate.According to percent prevalence per lumbar segment,L1,2 was the most common level (29.1％),followed by L3,4 (23.7％) and L2,3 (21.1％).The incidence of SN was positively correlated with elder age,but not with sex,body weight,height,or body mass index.SN occurred more often in bulging,extrusion,Modic changes,spondylolisthesis and osteophyte comparing with normal disc or protrusion or high intensity zone.The distributions of the grade of intervertebral disc degeneration were significantly different between groups with and without adjacent SN.Intervertebral discs with adjacent SN were more degenerated than those without adjacent SN.The number,size and volume of SN were associated with the degrade of intervertebral discs degeneration.SN was divided into two types,i.e.,acute edematous SN and non-acuteSN,according to the signal type on T1-and T2-weighted MR images,and the degeneration of the corresponding intervertebral discs was more severe in the latter than the former group.Conclusion SN occurred more often in the upper lumbar spine and cranial endplate in patients with low back pain or radiculopathy.SN were correlated with elder age and the degeneration of lumbar intervertebral discs.The number,size,volume and signal type on MR images of SN impacted on its correlation with lumbar intervertebral disc degeneration.

The morphology and position of the AV node and AV bundle were observed in 13 human hearts with serial sections. 1.the AV node is a long sagittal flatt ened structure, its transverse section is triangular in shape with a right convex surface, sometimes the cross section is fusiform or half oval in shape. Its size is 3.5x3.3x1.1 mm in adult. In 5 cases the endocardium lying on the right surface of the AV node is elevated.2.The AV node is situated in the upper border of the atrioventricular septum (between the levels of the attachment lines of the mitral and tricuspid valves). The adult AV node is 1.8-5.8 mm anterior to the coronary sinus orifice, 0.3-0.7 mm from the endocardium of the right atrium, 3.3-7.5 mm above the upper border of the septal leaflet of the tricuspid valve. The left surface of the AV node contacts with the central fibrous body.3.The AV node can be divided in 2 parts: superficial and deep, the fibers of the super ficial part are longitudinal in sections and end in the lower border of the AV node. In one case, the deep part is subdivided in an upper part and a lower part. In the specimens in which the right atrial endocardium lying on the right surface of the AV node is elevated, the overlaying fibers end in the endocardium. At the upper border, right surface, and posterior margin of the AV node, there are atrial fibers ending to the AV node. 4. The adult AV bundle is 5.7-7.9 mm long, 1.1-1.5 mm in diameter. Its anterior part is on top of the muscular interventricular septum in 7 specimens, on its left surface in 3 specimens, and in the substance of the muscular interventricular septum in 2 specimens. In one case its course is very special, at first on the top of muscular interventricular septum, then at its left surface, finally in the substance of the right part of the muscular interventricular septum.

Objective To investigate causes and treatment strategy of cage retropulsion after lumbar interbody fusion,in particular the correlations between the injury of the posterior part of endplate cranially adjacent to fusion and cage retropulsion.Methods Data of 7 patients with cage migration after lumbar interbody fusion from August 2011 to July 2014 in our hospital were retrospectively analyzed.There were 4 males and 3 females,aged from 45-74 years (average,53.6 years).All patients took X-ray and CT scans examinations 3 d postoperatively,and they were followed up at 3,6,12 months after operation.The characteristics of the patients and the injury of the endplate adjacent to fusion were analyzed to identify possible risk factors of cage retropulsion.Moreover,corresponding managements were performed and outcomes were recorded.Results All 7 cases of cage retropulsion occurred within 3 months post-operatively (rang,15-67 d).Posterior part of the endplate superiorly neighboring to fusion was found injured on the decompression side in all cases with cage retropulsion,and that led to an increase in the posterior intervertebral space height at the fusion segment.Other factors,including pear-shape type endplate,and improper operative manipulations may add the risk of cage retropulsion.These 7 patients complained mild back pain or no back pain,and received corresponding treatments including bed rest,activity limitation,and oral administration of anti-inflammatory analgesics.The clinical symptoms and degrees of cage retropulsion were not aggravated during follow-up.Conclusion The injury of the posterior margin of end-plate superiorly neighboring to fusion on the decompression side which caused increased posterior intervertebral space height may be key to postoperative cage retropulsion.Prevention of possible iatrogenic injury to the endplate may be effective to reduce the risk of cage retropulsion.