Objective:To propose a monosegment thoracic and lumbar fracture dislocation (mTLFD) classification, and to evaluate its reliability and clinical application.Methods:All of 298 cases of thoracic and lumbar fracture dislocation who received surgical management in our hospital from January 2014 to December 2019 were retrospectively analyzed. 123 cases were included in the study according to inclusion and exclusion criteria. mTLFD classification was proposed based on the imaging characteristics: type I (intervertebral disc injury mainly) and type II (vertebral burst fracture mainly). The type II was classified based on distribution of injury segment: type IIa (T 11 and above) and Ttype IIb (below T 11). Six spinal surgeons (3 residents, 3 associate chief physicians) were selected to classify the 123 cases according to preoperative imaging data, and to perform reliability test of each type. The repeatability and reliability of the classification were evaluated by ICC index. Different management strategies were performedf or each type: type I was managed with posterior decompression interbody fusion and internal fixation; type IIa underwent posterior decompression and fixation, subtotal vertebral resection and fusion was performed if bony compromise was still present through intra-operative exploration. Type IIb underwent posterior decompression, posterolateral fusion and internal fixation on the first stage, while anterior subtotal vertebral resection and reconstruction was performed on the second stage if the bony compromise was still present based on post-operative CT examination. The American Spinal Injury Association (ASIA) grading of all patients was recorded, and the visual analogue scale (VAS), Oswetry disability Iindex (ODI) and local Cobb angle of each type was compared between pre-operation and final follow-up. Results:The average follow-up time of all patients was 10.4±1.8 months. The average repeatability and reliability ICC index of mTLFD of 3 residents and 3 deputy chief physicians were 0.926 and 0.964, respectively, and 0.746 and 0.907, respectively. The reliability ICC index of type I, type IIa and type IIb was 0.918, 0.947 and 0.962, respectively, and the repeatability ICC index was 0.930, 0.940 and 0.966, respectively. The neurological function recovery was obtained in 56 patients. The preoperative VAS of type I, type IIa and type IIb were 8.5±1.0, 8.4±1.0 and 8.3±0.9, and 2.0±1.1, 1.8±1.0 and 1.8±0.9 at the final follow-up (all P<0.001). The ODI of type I, type IIa and type IIb were 97.0%±2.1%, 97.1%±1.9% and 97.3%±2.1% before surgery, and 29.5%±6.8%, 27.0%±6.0% and 29.0%±6.7% at the final follow-up (all P<0.001). The local Cobb angles of type I, type IIa and type IIb were 20.9°±7.1°, 29.0°±9.1° and 26.4°±6.9° before surgery, and 12.5°±5.4°, 18.0°±9.1° and 13.1°±5.1° at the final follow-up (all P<0.001). Conclusion:The mTLFD classification proposed in this study has strong repeatability and reliability, and management strategy of each type have achieved satisfactory clinical efficacy, indicating that the classification has certain significance for management of thoracic and lumbar spine fracture dislocation.

Objective To analyze the incidence and risk factors of contralateral radiculopathy in patients after unilateral transforaminal lumbar interbody fusion (TLIF) surgery.Methods A retrospective study was conducted within 587 patients (average age 57.1 years,range 19-71 years) who underwent unilateral TILF from January 2010 to January 2014 in our hospital,including 334 males and 253 females.Patients were divided into a symptomatic group and an asymptomatic group.The causes of contralateral neurological symptom were evaluated according to the radiological data.The difference of pre-and post-operative contralateral foramen area (CFA),segmental angle (SA) and the clinical treatment outcomes (VAS,JOA score) were compared between two groups.Results Patients were followed up for 9-21 months,average 15.1 months.Post-operative contralateral radiculopathy occurred in 28 (4.8％) of the patients who underwent unilateral TLIF,including contralateral foraminal stenosis in 16 (57.1％,16/28),screw malposition in 5 (17.9％,5/28),contralateral lateral recess stenosis and/or newly developed disc herniation in 3 (10.7％,3/28),hematoma in 1 (3.6％,1/28),cement compression in 1 (3.6％,1/28),and unknown origin in 2 patients (7.1％,2/28).Nineteen (3.2％,19/587) of the 28 patients received revision surgery because of ineffective conservative treatment.Compared with the asymptomatic group,the difference of pre-and post-operative CFA was significantly smaller (-13.8±13.2 mm2) in symptomatic group,while the SA was significantly greater (7.0°±9.8°) in symptomatic group.The JOA score at 3 months after the surgery was significantly improved in asymptomatic group (63.0％±18.1％,P＜0.05).Conclusion The incidence rate of contralateral neurological symptom was 4.8％ in the present study.The potential risk factors associated with contralateral radiculopathy were predominantly contralateral foraminal stenosis and screw malposition.The excessive restoration of SA might have an effect on contralateral nerve compression,which should arouse the attention of the surgeon.

AIM:Toinvestigatewhetherautophagyisup-regulatedwhenresveratrol(Res)inducesapoptosis in chondrosarcoma , and to study the effects of autophagy inhibitor combined with Res on chondrosarcoma .METHODS:SW1353 cells were divided into 4 groups: control group, Res group, 3-methyladenine (3MA) group, and Res +3MA group.Electron microscopy was used to observe the autophagyosomes in control group and Res group .At the same time, the viability of the cells in the 4 groups was detected by CCK-8 assay.TUNEL staining and Western blotting (for determi-ning the levels of cleaved caspase-3, Bax and Bcl-2) were used to reflect levels of apoptosis in all groups .The expression of autophagy-related proteins Beclin 1, LC3-Ⅱ and p62 was detected by Western blotting .RESULTS: Exposure of the cells to Res resulted in a decrease in cell viability and an increase in the level of apoptosis ( P<0.05 ) .Compared with control group, the level of apoptosis was increased but the autophagy was decreased (P <0.05).Compared with Res group, the cell viability and the level of autophagy were decreased and the level of apoptosis was increased ( P<0.05 ) . CONCLUSION:Resveratrol induces apoptosis and autophagy , and inhibition of autophgay enhances resveratrol-induced apoptosis in chondrosarcoma .

Complete burst fractures of the L₅ is relatively uncommon. How to accomplish a rigid internal fixation as well as preserve motor function is an enormous challenge. We report such a case treated via a single posterior vertebrectomy with 270-degree decompression and reconstruction using titanium mesh cage. The disc between L₅/S₁ was preserved by placing the titanium mesh cage on the inferior endplate of the L₅. We hope this method can offer a possible solution for other surgeons when they meet a similar fracture pattern.
Adult ; Decompression, Surgical ; Fracture Fixation, Internal ; instrumentation ; methods ; Humans ; Internal Fixators ; Male ; Spinal Fractures ; surgery ; Surgical Mesh ; Titanium

Objective To develop a three-dimensional finite element model of atlantoaxial instability and compare the biomechanical properties of percutaneous anterior transarticular screw (ATS) and posterior transarticular screw (PTS) fixations.Methods A pathologic three-dimensional finite element model of atlantoaxial instability was developed from CT images of the upper cervical spine of volunteers with the aid of softwares,such as Mimics,Freeform,and Ansys.Percutaneous C1-2 ATS and PTS fixation modes were simulated and implanted to the model.Under the preload of 40 N and force moment of 1.5 Nm in anterior flexion,posterior extension,lateral bending,and axial rotation,biomechanical properties of the two fixation modes were compared.Results Under the four loading modalities,both fixation techniques provided maximal inhibition on C1-2 movement.The maximal stress for ATS was larger than that for PTS and maximal displacement for ATS was smaller than that for PTS.Conclusions Both ATS and PTS provide similar outlook and are effective to stabilize the atlantoaxial joint.Biomechanical performance of percutaneous C1-2 ATS is better than that of percutaneous C1-2 PTS.

Objective To compare the clinical efficacy and radiologic changes between constrained and non-constrained titanium plate in anterior cervical corpectomy and fusion (ACCF) in elderly cervical spondylosis patients.Methods A total of 58 elderly cervical spondylosis patients who underwent ACCF were divided into group 1 (patients treated with constrained titanium plates,n =30) and group 2 (patients treated with non-constrained titanium plates,n=28).The Japanese Orthopedic Association (JOA) score,fusion rate,the loss of segmental height and cervical lordosis were recorded.The clinical efficacy and imaging features were compared between the two groups.Results The improvement rate of JOA score had no significant differences between group 1 and group 2 [(77.7±18.6)％ vs.(75.8±23.2)％,t=0.340,P＞0.05].At 3 months after operation,the fusion rate was higher in group 2 than in group 1 (89.3％ vs.63.3％,x2 =5.327,P＜0.05).At 3,6 and 12 months after operation,there were no significant differences in the loss of segmental cervical height and lordosis between group 1 and group 2 [(2.42±3.05)mm vs.(0.98±2.86)mm,(3.95±3.65)mm vs.(2.34±2.97)mm,(3.60±4.33)mm vs.(2.40±2.96)mm,(1.64±2.33)° vs.(0.66 ± ±2.14)°,(2.13∧±±3.79)° vs.(0.70±2.99)°,(2.39±4.26)° vs.(0.86±3.25)°,respectively,all P ＞0.05].Conclusions The clinical efficacy is similar in ACCF with the two types of titanium plates.The non-constrained titanium plate can increase the fusion rate in early time,but may aggravate the loss of segmental cervical height and lordosis,which should be used with caution in elderly osteoporosis patients.

We examined the biocompatibility and the safety of a-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites for bone reconstruction application. The biocompatibility of the CSH/MWCNT composites was evaluated by the measures which taking L929 fibroblast cells cultured in the extracted liquid of the composite soaking solution and putting bone marrow stromal cells planted on the composite pellets in vitro, respectively. The cell proliferation was evaluated by MTT test and further observed using an inverted optical microscope and a scanning electric microscope. The toxicity of the composites was evaluated by acute and subacute systemic toxicity test. Long-term muscle and bone implantation in vivo tests were also conducted. L929 fibroblast cells grew well in the extracted liquid, as well as bone marrow stromal cells that could adhere on the surface of sample pellets and proliferated rapidly. MTT test showed that there were no significant differences between the experimental and control groups (P > 0.05). In vivo test manifested that the composites were no toxicity, no irritation to skin and good for bone defect reconstruction. It was proved that a-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites exhibited excellent biocompatibility for the potential application in bone tissue engineering.
Animals ; Biocompatible Materials ; chemistry ; Bone Marrow Cells ; cytology ; Bone Substitutes ; chemical synthesis ; chemistry ; Calcium Sulfate ; chemistry ; Cell Line ; Cell Proliferation ; Fibroblasts ; cytology ; Materials Testing ; Nanotubes, Carbon ; chemistry ; Rabbits ; Stromal Cells ; cytology ; Tissue Engineering ; methods ; Toxicity Tests

Objective To investigate complications associated with Coflex interspinous process device for degenerative lumbar disc diseases and methods to treat.Methods Clinical data of 121 patients with degenerative lumbar disc diseases,who had undergone surgical decompression and additional fixation of Coflex between November 2007 and June 2011,was analyzed retrospectively.There were 76 males and 45 females,aged from 37 to 75 years (average,54.6 years).Surgery-related complications and sequelae were recorded and analyzed.Results Surgery-related complications occurred in 10 patients,and the incidence was 8.3％ (10/121).There were 3 cases of device-related complications,including wing break in 1 case,prosthetic loosening in 1 case and spinal process fracture in 1 case; all 3 cases were treated conservatively and received good results.There were 7 cases of non-device-related complications,including dura mater dilaceration in 2 cases,superficial wound infection in 1 case,insufficient decompression of spinal canal in 2 cases,recurrence of disc herniation in 1 case,and intraspinal hematoma in 1 case; the former 3 patients recovered after corresponding treatment,and the latter 4 patients also recovered after re-operation.Conclusion The incidences of complications and re-operation associated with application of Coflex are low,and the incidence of device-related complications is also low.The precise intraoperative manipulation is the key to reduce incidence of device-related complications.It's absolutely necessary to strictly master surgical indications and perform sufficient decompression in order to receive good surgical results and avoid non-device-related complications.

ObjectiveTo analyze the stress contribution of different cement volume to the adjacent vertebral endplates in percutaneous kyphoplasty (PKP) so as to explore the possible mechanism of adjacent vertebral fractures after PKP.Methods The three-dimensional finite element model of osteoporotic thoracolumbar vertebral compression fractures was established to simulate vertebral body partial restoration (80％) with PKP.During the process,two doses of bone cement ( polymethylmethacrylate,PMMA) were filled in the vertebral body (4.0 ml bone cement filling 15％ of the vertebral body volume and 8.0 ml bone cement filling 30％ of the vertebral body volume).Endplate stress under conditions of axial compression,flexion and extension was analyzed. ResultsRegarding the two filling doses in PKP,the adjacent vertebral endplate stress under the above-mentioned conditions was all increased at T11 and L1 vertebral body compared with that before operation.Meanwhile,endplate stress had positive correlation with the cement volume and the stress concentrated largely in the anterior and middle parts of endplate.ConclusionsThe stress of adjacent vertebral endplate is positively correlated with cement volume,with anterior and middle parts of endplate as the stress concentration.The probability of adjacent vertebral fractures shows a rising trend with the increase of cement volume in PKP.

Objective To evaluate the effect of different preparation processes on preparation of the glial cell line-derived neurotrophic factor(GDNF)loaded microspheres and observe the biological activity of GDNF.Methods With polylactide-co-glycolide(PLGA)as the coating material,the GDNF-loaded microspheres were prepared by using double emulsion(W1/O/W2).Two-factor factorial design variance analysis was done to analyze the effects of the composition proportion of lactic acid(LA)and glycolic acid(GA)in PLGA and the stirring speed of multiple emulsion on particle size,entrapment efficiency,burst release and in vitro release characteristics of the GDNF-loaded microspheres.PC-12 bioassay was employed to detect the biological activity of the released GDNF so as to determine the optimal preparation process.Results The composition proportion of PLGA could affect the microspheres'burst release(P ＜ 0.05),with no effect on particle size and entrapment efficiency.with the higher.With higher proportion of GA,the release speed of GDNF in the microspheres was increased.When the stirring speed of multiple emulsion was increased from 1 000 r/min to 3 000 r/min,the particle size of the microspheres was decrease significantly(P ＜ 0.01),the burst release was increased markedly(P ＜ 0.01)and the in vitro release rate was accelerated.The activity of GDNF in the microspheres could last for about 20 days at 37℃,which was 10 days longer than that of single GDNF.Conclusions Double emulsioncan prepare the GDNF-loaded microspheres with high entrapment efficiency and suitable in vitro release time.In the meantime,the microspheres can extend the validity of GDNF.