Objective To investigate efficacy of KumaFix posterior spinal screw/rod system (KumaFix system) for thoracolumbar fractures.Methods Thirty patients with type A3 thoracolumbar fractures treated from June 2011 to June 2012 were divided into Group A and Group B according to odd and even number.Group A (n =15) underwent reduction and fixation with KumaFix system in combination with transpedicular bone grafting of fractured vertebrae.There were 7 males and 8 females at average age of (40.5 ±5.1) years (range,21-52 years).Group B (n =15) underwent posterior reduction and fixation with U-shaped screw/rod system in combination with transpedicular bone grafting of fractured vertebrae.There were 8 males and 7 females at average age of (41.3 ±4.8) years (range,22-51 years).Two groups were analyzed and compared in aspects of operation time,blood loss,visual analogue scale (VAS),anterior vertebral height ratio,kyphosis angle,spinal canal encroachment ratio,and Oswestry disability index (ODI).Results All patients were followed up for average 13.2 months.Operation time was shorter in Group A than in Group B (P ＜ 0.05),but there was no significant difference in blood loss between the two groups (P ＞ 0.05).Both groups achieved obvious improvement in aspects of VAS,anterior vertebral height ratio,kyphosis angle,spinal canal encroachment ratio after operation (P ＜ 0.05).ODI score was improved for the two groups after operation (P ＜ 0.05) and was better in Group A than in Group B at the last follow-up (P ＜ 0.05).Conclusions For treatment of type A3 thoracolumbar vertebral body fractures,the KumaFix system is able to achieve gradual,smooth and controllable distraction reduction that is conducive to the implement of transpedicular bone grafting of fractured vertebrae in comparison with the U-shaped screw/rod system.In the meantime,the KumaFix system avoids negative effect of internal fixation on adjacent articular process.

Objective To investigate the effect of different bone cement volume injected after vertebroplasty on stress distribution of the upper and lower endplates of the injured vertebra in the flexion and extension positions by finite element analysis.Methods Two patients with osteoporotic compression fractures of L2 vertebral body were chosen.Bone cement volumes of 25％ and 50％ were respectively injected into the fractured vertebral body bilaterally.Pre-and post-operative finite element models of fractured and adjacent vertebral bodies were developed after extracting the CT data.Stress changes at L2 superior-and inferior-vertebral endplates were observed in the vertical,flexion,and extension loading.Results Stress at the upper and lower endplates of the fractured vertebra increased after bone cement injection and more increase was observed in 50％ bone cement group than in 25％ bone cement group.In the neutral position,the stress mainly concentrated at posterior vertebral body,with stress of the upper endplate improving from 0.91 × 106 N · mm to 0.93 × 106 N · mm and stress of the lower endplate from 0.98 × 106 N ·mm to 1.03 × 106 N · mm.In the anterior flexion,the stress mainly concentrated at anterior vertebral body,with stress of the upper endplate improving from 4.44 × 106 N · mm to 5.55 × 106 N · mm.In the posterior extension,the stress mainly concentrated at medial vertebral body,with stress of the upper endplate improving from 21.95 × 106 N · mm to 22.10 × 106 N · mm and stress of the lower endplate from 30.60 ×106 N · mm to 30.88 × 106 N · mm.The finite element model revealed stress at the upper and lower endplates was higher in the anterior flexion and posterior extension than in the neutral position,while in the anterior flexion the stress was comparatively higher.Conclusions A small amount of implanted bone cement act no evident effect on stress distribution of the upper and lower vertebral endplates.However,the stress changes are significant as cement volume reached up to 50％,especially in the flexion position,as may suggest an enhanced risk of adjacent intervertebral disc degeneration and adjacent vertebral body fractures.

Objective To discuss the selection of surgical treatment for lower cervical fractures and dislocations combined with locked-facet. Methods The clinical data of 68 patients with lower cervical spine fracture and dislocation combined with locked-facet were retrospectively analyzed. There were 33 patients with unilateral facet dislocation and 35 with bilateral facet dislocation. According to American Spinal Injury Association (ASIA) score, there were five patients at grade A, 11 at grade B, nine at grade C and 10 at grade D. All patients underwent skull traction. Anterior decompression and fixation were applied for reduction of the locked facet. Posterior unlocking reduction ,anterior decompression and plat fixation were applied for the patients with no reduction. Results There were no injuries on major blood vessels, trachea, esophagus, spinal cord. The follow-up lasted for average 41.5 months, which showed that the intervertebral height and lordosis were maintained normal. At six months postoperatively, bony fusion was achieved, with no plate and screw-related complications. The patients with neurological defect got improved at different degrees postoperatively. Conclusion For different lower cervical spine fractures and dislocations combined with locked-facet, selection of suitable surgical approach can attain satisfactory outcome.

Objective To compare the clinical outcomes of Bryan disc replacement with anterior cervical discectomy and fusion (ACDF) in patients with cervical spondylopathy. Methods Sixteen patients underwent Bryan cervical disc replacement (A group), and 35 patients underwent traditional ACDF (B group) were included in the study. Patients were followed up at regular intervals. The JOA score, SF-36, neck disability index (NDI) score and the dynamic flexion-extension radiographs were used to evaluated the oucomes.Results All the patients were followed up for more than 6 years (mean, 73.5 months). There were no severe adverse events in both groups. In A group, there were no differences between postoperative and preoperative mobility of surgical segments (P＞0.05). All patients obtained bone fusions 6 month after surgery in group B.In both groups, the clinical symptoms relieved obviously after surgery. The postoperative scores of the JOA,SF-36 and NDI significantly improved compared with those of preoperative ones (P＜0.05). In B group, range of motion (ROM) was significantly decreased postoperatively (P ＜0.01); in A group, there were no significant differences between postoperative and preoperative ROM (P＞0.05). The difference between two groups regarding ROM was noted (P＜0.05). Conclusion The mid-term outcomes of Bryan cervical arthroplasty are satisfied. And the cervical arthroplasty which can maintain the mobility of the segment, and decrease the incidence of the postoperative neck axial symptoms is a viable alternative to cervical spondylopathy.

Objective:To investigate the role of MicroRNA-9-1 in inducing epidermal stem cells(ESCs) differentiation into neurons.Methods:The lentiviral of MicroRNA-9-1 was constructed and transfected into rats epidermal stem cells.The experiment was divided into transfected group,non-transfected group and the negative control group.The β-mercaptoethanol was as an inducer for triggering the ESCs to differentiate into neurons.The GFP fluorescence expression of epidermal stem cells after transfection was observed under inverted fluorescence microscope.The protein and mRNA expression level of microtuble-associated protein 2 (MAP-2) was detected by immunocytochemical method and RT-PCR,respectively.Results:The result of Positive clone PCR confirmed successful construction of MicroRNA-9-1 in rats.Transfection after 48 h,the expressing of GFP fluorescence at peak in transfected group,and transfection efficiency reached (85.6+1.9)％.Most ESCs differentiated into neurons in transfected group after β-mercaptoethanol induction 7 h,and the effect was significantly better than non-transfected group and the negative control group.The protein ((87.3± 0.6)％) and mRNA (about twice over) expression levels of MAP-2 in transfected group was higher than those in non-transfected group and the negative control group (P＜0.05).Conclusion:The lentiviral of MicroRNA-9-1 has high transfection efficiency in rats ESCs,and could promoted ESCs differentiate into neurons under β-mercaptoethanol induced.

Objective To explore the causes and clinical treatments of recurrent spinal tuberculosis complicated with sinus tract.Methods There were 21 patients suffered from recurrent spinal tuberculosis complicated with sinus tract in 87 patients with complicated spinal tuberculosis from January 1997 to January 2012.The dates of them were reviewed.There were 12males and 9 females with an average age of 38.8 years (range,22-58 years).There were 15 patients whose tuberculosis bacterial culture and drug sensitive experiments suggested drug resistance.All patients were excluded from mixed infection of sinus before the operation.According to the range of the tuberculous abscess,11 patients had undergone one stage sinus clearing and debridement,instrument removal,spinal fusion and internal fixation by anterior approach.The other 10 patients had undergone one stage anterior sinus clearing and debridement,instrument removal,bone graft and internal fixation by posterior approach.Results All patients were followed up for an average time of 29.7 months.16 patients were recovered.5 patients got recurrence with the rate of 23.8％(5/21).The recurrence rate of anterior internal fixation was 18.2％(2/11),and 30％ (3/10) for posterior internal fixation.3patients got recovered by conservative treatment and 2 patients by re-debridement.15 patients achieved bone fusion 6 months after the operation; 4 patients achieved bone fusion 9 months after the operation; 1 patient achieved bone fusion 12 months after the operation.The kyphosis Cobb' angle was corrected to 5.7°(ranged from 2° to 12°).Conclusion It is difficult for the treatment of recurrent complicated spinal tuberculosis combined with sinus tract.The causes of recurrence include drug-resistant strains of TB,uncompleted debridement,failure of spinal stability reconstruction,and combination with other organ tubeculosis.The key of successful surgical treatment includes effective chemotherapy,radical debridement and proper reconstruction of spinal stability.

Bone cement leakage is the most common complication in the treatment of thoracolumbar osteoporotic fractures by percutaneous vertebroplasty.The incidence rates of the literatures are different,with the range from 5％ to 80％.There are several different classifications of cement leakage;however there is no uniform classification standard.The classification criteria' s are based on anatomical location and leakage way.The independent risk factors of cement leakage are fracture semiquantitative severity grade and the viscosity of bone cement.The incidence rate of cement leakage increases with high fracture semiquantitative severity grade and low bone cement viscosity.For cortical leakage,the presence of cortical disruption and intravertebral cleft on MRI were identified as additional strong risk factors.The majority of bone cement leakage does not produce clinical symptoms.But some of the patients suffered from new adjacent osteoporotic vertebral compression fractures,neurologic deficits,pulmonary cement emboli,cardiac perforation,and even death.Therefore,we should strictly grasp the indications,select appropriate filling materials,and improve surgical techniques to avoid the occurrence of bone cement leakage.

Objective To evaluate the reliability and reproducibility of the thoracolumbar osteoporotic vertebral compression fracture (OVCF) severity score system (TLOFS),so as to provide basis for clinical decision-making.Methods A total of 320 cases of thoracolumbar OVCF hospitalized between January 2014 and June 2015 were scored by TLOFS.There were 107 male and 213 female patients,aged 52-90 years (mean,63.78 years).All cases presented with a chief complaint of low back pain.Thirty-nine cases (TLOFS ≤3 in 21 cases,TLOFS =4 in 17 cases) were treated non-operatively,while 259 cases (TLOFS =4 in 23 cases,TLOFS ≥ 5 in 259 cases) were treated surgically.Pain was evaluated by the visual analogue scale (VAS).Reliability,reproducibility and content validity of the TLOFS were analyzed.Results Cronbach' sα coefficients of all TLOFS subgroups including evaluation of morphological changes,MRI,bone mineral density,clinical situation and therapy recommendation and total score evaluation were within the range of higher to high reliability (0.76-0.94).Kappa coefficients of all TLOFS subgroups were within the range of higher to high reproducibility (0.84-0.95).Mean content validity of all TLOFS subgroups was 0.916.VAS improved from preoperative(7.8 ± 2.1) to (1.3 ±0.7) at the final follow-up.Rates of correct diagnosis,sensitivity and specificity were 95.7％,87.6％ and 96.5％ respectively.Conclusion TLOFS exhibits good reliability and reproducibility,easy operation,and accurate and comprehensive evaluation,which is effective in guiding the clinical decision making in treatment of thoracolumbar OVCF.

Objective To compare the efficacy of KumaFix posterior spinal screw/rod system (KumaFix system) and posterior U-shape screw/rod system for treatment of thoracolumbar vertebral body fractures.Methods A total of 131 patients with thoracolumbar vertebral body fractures treated from January 2011 to July 2011 were prospectively analyzed.All patients showed thoracolumbar injury classification and severity score (TLICS) more than 5 points and spinal load-sharing classification (LSC) score of 4-6.The patients were assigned to two groups according to the coin toss method:group A (n =72,treated with reduction and fixation with KumaFix system in combination with transpedicular bone grafting of fractured vertebrae) and group B (n =59,submitted to posterior reduction and fixation with U-shaped screw/rod system in combination with transpedicular bone grafting of fractured vertebrae).In group A,there were 41 male and 31 female patients at age of (41.2 ± 4.9) years (range,20-53 years).In group B,there were 33 male and 26 female patients at age of(40.6 ± 4.5)years (range,21-51 years).The two groups were analyzed and compared in aspects of operation time,blood loss,anterior vertebral height ratio,middle vertebral height ratio,posterior vertebral height ratio,kyphosis angle,Oswestry disability index (ODI) and incidence of adjacent segment degeneration.Results All patients were followed up for mean 5.3 years (range,5.1-5.8 years).Operation time and blood loss were (72.5 ±21.8)rain and (320.6 ±90.0)ml in group A,less than (104.3 ±20.7)min and (421.0 ± 84.5) ml in group B (P ＜ 0.05).Both groups achieved obvious improvements in anterior vertebral height ratio,middle vertebral height ratio,posterior vertebral height ratio and kyphosis angle after operation(P ＜ 0.05).At the last follow-up,the middle vertebral height ratio was (92.0 ± 2.8) ％ in group A,better than (84.1 ± 5.1) ％ in group B (P ＜ 0.05).Both groups showed improvement in ODI after operation (P ＜ 0.05).At the last follow-up,ODI and incidence of adjacent segment degeneration were 11.9 ± 7.1 and 0 in group A,decreased compared to 20.9 ± 6.7 and 12％ in group B (P ＜ 0.05).Conclusions For thoracolumbar vertebral body fractures,the KumaFix system has better reduction effect than U-shape screw/rod system.Meanwhile,the KumaFix system can avoid negative effect.

Objective To evaluate biomechanical effect of bone cement distribution on lumbar vertebral body with osteoporotic fracture.Methods Forty nine lumbar vertebrae (L1-L5) specimens were collected from 12 old cadavers.After exerting axial pressure load on every specimen,the initial intensity and stiffness were measured,and then vertebral body crush fracture models were established.According to zones where bone cement was injected in vertebrae,the specimens were divided into one control group and six experimental groups:A,B,C,D,E,F groups,i.e.unilateral anterior 2/3 group,unilateral posterior 2/3 group,unilateral whole group,bilateral anterior 2/3 group,bilateral posterior 2/3 group,and bilateral whole group,respectively,including 7 specimens in each group.In A,B,C groups,unipedicular balloon kyphoplasty was done,while in D,E,F groups,bipedicular balloon kyphoplasty was done.Then the maximum compressive strength and stiffness were measured.Results After percutaneous kyphoplasty,the maximum strength in all experimental groups was significantly greater than that in the control group.There were no significant differences in strength between A and B groups,between C,D and E groups.For the maximum strength,the results of comparison were:F group ＞ C group,D and C groups ＞ A and B groups.Except for F group,the stiffness in other 5 experimental groups was significantly lower than its initial value.There were no significant differences in stiffness between A,B,and C groups,between D and E groups.However,the stiffness in F group was greater than those in D and E groups,and it was greater in bilateral groups than those in unilateral groups.Conclusion Bone cement distribution in lumbar vertebral body can affect biomechanical property of vertebral body,and the bilateral distribution can cause better biomechanical effect than unilateral distribution.The ideal distribution zone of bone cement is in the anterior 2/3 of the vertebral body.