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BACKGROUND:The cervical spine of the human body is an important structure carrying the head and connecting the spine. Its volume is smal, but its flexibility was great. Activity frequency was highest. Simultaneously, cervical spine is the most complicated bony structure of geometric and kinematic characteristics of human body, bears the physiological load of the head, has functions of flexion and extension, lateral bending and rotation. Therefore, the cervical spine has become one of the most vulnerable structures with degenerative diseases of the spine. Analysis of upper cervical spine biomechanics, recognition and understanding of its normal function and mechanical mechanism wil provide a theoretical basis for better treatment of upper cervical spine disorders. OBJECTIVE:To observe thein vivothree-dimensional kinematics of the upper cervical spine in healthy human beings under physiological load with dual fluorescence X-ray imaging system and spiral CT. METHODS:Seventeen healthy volunteers were recruited for this study. The vertebral segment motion of each subject was reconstructed with three-dimensional computed tomography and solid modeling software.In vivo cervical vertebral motion during functional postures was observed with dual fluoroscopic imaging. Coordinate systems were established at the vertebral center to obtain the intervertebral range of motion. RESULTS AND CONCLUSION: (1) During the flexion-extension motion, significant differences in the distance in coronal axis, sagittal axis and angle of rotation were detected in C1-2 and C2-3segments. (2) During the left-right bending motion, the angle of rotation was obviously greater at C1-2 segment than that at C2-3segment. During the left-right twisting motion, significant differences in distance of the vertical axis and the coronal axis, lateral flexion angle and rotation angle were detectable between C1-2and C2-3 segments. (3) These findings confirmed that dual fluorescence X-ray imaging system combined with CT scan can obtain atlanto-axial three-dimensional instantaneous motion of six-DOF data of healthy adults, and found that the main motion of the C1-2 vertebrae is rotating. These data may provide us with some new information about the in vivo kinematics of the upper cervical spine and the non-fixed surgical operation.
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BACKGROUND:Gait deviations are the important diagnosis criteria and surgical indications of cervical myelopathy. Conventional three-dimensional gait laboratory failed to apply in clinics due to complex operations and time consuming. In recent years, a portable gait analyzer based on the micro-sensors is emerging and developing, it has been verified by clinical practice, al owing gait analysis in the ward. OBJECTIVE:To quantitatively analyze gait characteristics of patients with cervical spondylotic myelopathy (CSM) by a portable gait analyzer. METHODS:From March 2013 to November 2013, 15 CSM patients and 30 healthy subjects were enrol ed in the study. The involved patients were accompanied by gait abnormalities. A portable gait analyzer was used for gait analysis. Subjects walked on a 30-meter corridor back and forth for 120 meters. Total y 12 gait parameters were involved in this study, including seven common parameters (single limb support, double limb support, gait cycle, speed, cadence, step length and stride length) and five new parameters (pul ing acceleration, swing power, ground impact, foot fal , and pre-swing angle). Three patients underwent cervical decompression surgery. The gait characteristics were re-evaluated one week later, carrying neck support. RESULTS AND CONCLUSION:The double limb support and gait cycle duration of CSM group were significantly longer than control group (P0.05). after cervical decompression surgery, the mean remission rate of Japanese Orthopedics Association scores was 32.5%and lower limb acceleration was improved obviously in the graph one week after surgery. Varying degree of correlation was seen between Japanese Orthopedics Association scores and the detected 12 gait parameters in CSM patients. The portable gait analyzer can effective measure the pathological gait deviation in CSM patients with abnormal gaits, and assists to evaluate the lower limb functions.
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Objective To observe and compare in vivo segmental lumbar motion between symptomatic L4 isthmic spondy?lolisthesis (IS) patients and L4 degenerative spondylolisthesis (DS) patients during functional weight?bearing activities. Methods Fifteen symptomatic L4 IS patients and fifteen symptomatic L4 DS patients were recruited. Fifteen asymptomatic volunteers were en?rolled as the control group. The L4,5 vertebral segment motion of each subject was reconstructed using three?dimensional computed tomography and a solid modeling software. In vivo, lumbar vertebral motion during functional postures (flexion?extension, left?right twisting and left?right bending) was observed using a dual fluoroscopic imaging technique. The spinal function unit was divided in?to anterior and posterior segments by the isthmic cleft. Local coordinate systems were established at the vertebral body, to obtain the 6 degree?of?freedom (DOF) intervertebral range of motion (ROM) at L4,5 and the ROM between the anterior and the posterior segments of L4 IS. Results The motion of IS at L4,5 was found to be increased. The migrations along both sagittal and vertical axis were significantly larger than control group (P<0.05). During left?right twisting, the migration along sagittal axis was significantly larger than control group (P<0.05);the rotation along vertical axis was significantly larger than DS and control group (P<0.05). During left?right bending, the migration along frontal axis was significantly larger than DS and control group ( P<0.05). The inter?vertebral ROM at L4,5 showed no significant difference between DS and control group. The migration between anterior and posteri?or segments of IS L4 was larger in standing than supine (P<0.05). The relative migration along sagittal axis between anterior and posterior segments of IS L4 was significantly larger in flexion than standing (P<0.05). Conclusion A spondylolytic defect does lead to detectable instability or hypermobility in the lumbar spine compared with degenerative spondylolisthesis and normal group. From supine to standing posture, migration at isthmic cleft along sagittal and coronal axis are identified in IS spondylolithesis.
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Objective To evaluate the mid-term clinical and radiographic results of artificial disc replacement (ADR) for discogenic low back pain.Methods From July 2004 to July 2007,21 patients with discogenic low back pain,aged from 26 to 67 years,underwent lumbar ADR with the Charité Ⅲ artificial disc at 22 levels and Activ L prosthesis at 2 levels:L4-5 5 cases,L5S1 13 cases,L4-5 and L5S1 3 cases.The diagnosis was proved by discography in all the patients.The clinical and radiographic results were evaluated and compared between pre-,post-operation and finial follow-up.Results All patients were followed up for 4to 7 years (average,5.1 years).There were statistical differences between pre-operation and final follow-up in Oswestry disability index and Visual Analogue Scale for back pain and leg pain.All the prostheses were mobile without dislocation,breakage,subsidence or spontaneous fusion,only a slight scoliosis was noted in one patient.At the ADR levels,the anterior and posterior intervertebral height increased averagely 6.3 mm and 1.9 mm respectively,the lordosis increased 2.9°,and the mean range of motion (ROM) was 4.6°.At the adjacent level proximal to ADR,the intervertebral height and lordosis decreased slightly,and the ROM decreased 2.5°.The total lumbar lordosis increased 7.8°,and the total lumbar ROM increased 2.4°.According to MRI and CT scans,the degeneration of proximal adjacent disc and facet were not evident,however the degeneration of facets at the ADR levels was evident.Conclusion The 5 years results of ADR for discogenic low back pain were satisfactory,with preserved motion at the ADR level,and the degeneration of adjacent level was not evident.However,there was obvious degeneration in facet joints of the ADR level.
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ObjectiveTo observe in vivo segmental lumbar motion in patients with lumbar disc herniation (LDH) during functional weight-bearing activities.MethodsFifteen patients with LDH at L4-5 were studied as experimental group.Ten healthy volunteers were recruited as control group.Three-dimension(3D) lumbar spine models of L3,L4 and L5 were reconstructed from thin section CT scans.Spine motions were then reproduced by matching lumbar spine models and images got from dual fluoroscopic imaging system (DFIS)under different motion state (standing,flexion-extension,left-right twisting and left-right bending).From local coordinate systems at the end plates,the motion of the cephalad vertebrae relative to the caudal vertebrae was calculated for vertebrae levels:L4-5 and L3-4.ResultsThe motion pattern at L4-5 was found to be altered.During flexion-extension,the migrations of the affected segments along the frontal axis,sagittal axis,vertical axis were similar with that of the control group,but the rotation angle along the frontal axis was significantly larger than that of the control group (P＜0.05).During left-right bending and left-right twisting,the migration and rotation angle along the frontal axis were significantly larger than those of control group.During flexionextension,the migrations of the neighboring segments (L3-4) along the three axes were larger than those of the control group,but there were no statistical significances.During left-right bending and left-right twisting,the migrations of the neighboring segments (L3-4) along the vertical axis were significantly larger than those of the control group (P＜0.05).ConclusionThe 3D lumbar motion pattern in LDH patient is different with that of normal people.For the affected segment,compared with the normal people,the range of flexion-extension motion and the translocation in left-right direction were significantly larger,but the rotation range along the vertical axis was smaller.
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Objective To evaluate the correlation between homologous recombination repair protein RAD51 and methotrexate-enhanced radiosensitivity.Methods Western blot and RT-PCR assays were used to detect RAD51 expression in HOS osteosarcoma cells exposed to γ-ray irradiation alone and in combination with methotrexate.Colony formation assay was used to test the survival fraction of HOS cells exposed to γ-rays and methotrexate.Results Methotrexate inhibited both protein and RNA expressions of RAD51,and the combination of radiation and methotrexate enhanced the inhibition of RAD51 expression.Moreover,transfection of cells with RAD51 gene decreased cellular sensitivity to methotrexate and γ-rays.The sensitizer enhancerment ratios after irradiation in combination with methotrexate were 1.51 and 0.99,respectively.Methotrenate was a preferred radiosensitizer to HOS cell.Conclusions RAD51 might be involved in the methotrexate-enhanced radiosensitivity.
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ObjectiveTo evaluate the effectiveness at anterior lumbar interbody fusion (ALIF) with a single cage alone in treatment of lumbar degenerative disc disease(DDD).MethodsThirty-four patients aged from 26 to 67 years (mean,52) were enrolled in this study,including 10 males and 24 females.Preoperative diagnosis included:degenerative spondylolithesis in 11 cases,discogenic low back pain in 21,and revision for failed posterior surgery in 2.Objective level located in L4.5 in 12 cases,L5S1 in 20,and double discs(L4.5,L5S1) in 2.All the patients received extraperitoneal approach ALIF.Surgical time,blood loss,perioperative complications and postoperative ambulation were noted.Postoperative function status was evaluated by 100 mm Visual Analog Scale (VAS) and Oswestry Disability Index (ODI50).AP,lateral and dynamic X-rays were routinely taken during follow up,according to which disc height,migration of implant and bony fusion were measured.ResultsAll the surgeries were performed successfully with a mean surgical time of 90 min and blood loss of 200 ml.An injury to the bifurcation of vena cave was encountered in an early case,after meticulous repairing of the vessel,the surgery was finished successfully.Peritoneum rupture was noticed in one case.One case of postoperative cage migration was revised and reinforced with additional fixation system.All the patients were followed up for an average of 36 months(range,12-60).All the patients were satisfied with the pain relief and returned to normal social life and working.VAS decreased from preoperative 70 to postoperative 5,and ODI decreased from 41％ to 6％.All but one migration case reached sound fusion with a fusion rate of 97％.ConclusionOwing to multiple advantages,complete removal of degenerative disc,compressive bone graft,sufficient graft area,early ambulation,less complication,extrapefitoneal approach for ALIF comes up with satisfying clinical outcomes.This mini_invasive technique provides a valuable alternative to treatment of lumbar DDD when appropriate indication is selected.
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Objective To discuss the value of thoracolumbar injury classification and severity score (TLICS) and load-sharing scores in guiding selection of the indications of combined anteroposterior surgery for thoracolumbar fractures. Methods A total of 216 patients with thoracolumbar fractures treated surgically from January 2006 to January 2008 were involved in the study. Combined anterior and posterior surgery was carried out in 48 patients including 32 males and 16 females (at average age of 39 years, range 18-55 years). Segments involved T11 in two patients, T12 in eight, L1 in 20 and L2 in 18. According to the classification of Magerl, there were 20 patients with type B1 fractures, 15 with type B2, four with type C1 and nine with type C2. Neurologic status based on ASIA classification was at grade A in five patients, grade B in 16, grade C in 16, grade D in nine and grade E in two. All patients were operated in lateral position at one stage within 14 days after injury, with posterior laminectomy and pedicle fixation, anterior corpectomy, reduction and strut graft. Forty-five patients were followed up for 14-38 months. Plain X-ray radiographs and reconstruction CT were taken to observe the bone healing. Local kyphosis and vertebral canal were also measured. All the patients were evaluated with TLICS and load-sharing scores. Results Lumbar physical lordosis was reconstructed, with no evident correction loss,pseudoarthrosis or implant failure noted during follow-up. The patients treated with combined surgery had TLICS score ≥5 points, load-sharing scores ≥7 points and were combined with posterior ligamentous complex injury, so the fracture could not be sufficiently decompressed and reconstructed with single anterior or posterior surgery. Of all, 45 patients were followed up for 14-38 months (mean 25 months), which showed that all the combined surgeries were performed successfully, with bone fusion and neurological status improved for at least one ASIA grade. No complications like implant breakage, loosening, titanium mesh displacement or subsidence were observed. Conclusions LICS is basically helpful for guiding selection of combined surgery, but does not well evaluate the canal compromise, to which the load-sharing scores can supplement. These two evaluation systems should be applied together. The anteroposterior surgery can be recommended when the patients are with TLICS≥5 points, load-sharing score ≥7 points and combined with ligament complex injury.
