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BACKGROUND:It is generaly believed that the spine wil be extended, and vertebral muscle atrophy, bone loss of vertebral body, increased height and area of intervertebral disc, changes of composition of intervertebral disc wil occur in the condition of weightlessness. These are likely to be the cause of high incidence of low back pain. OBJECTIVE:To observe changes in lumbar spine bone microstructure analysis of simulated weightlessness on rhesus lumbar spine biomechanics. METHODS:Fourteen young rhesus monkeys were randomly divided into two groups: control group (n=7;free activities in the cage during the experiment), and experimental group (n=7; the use of head-down-10° on a special bed by bundle lying to simulate weightlessness). RESULTS AND CONCLUSION:(1) The results of Micro-CT examination: in the experimental group, structure model index in trabecular bone of increased. Trabecular bone changed from plate-like to the rod-like change. The intersection number of bone tissue in unit length to non-bone tissue declined. The average width of the canal between the trabecular bone increased, suggesting that there have been signs of osteoporosis in the experimental group. (2) Under an optical microscope, in the experimental group, bone hyperplasia line was disordered and irregular. Thick endplate trabecularbone became smal, shalow, and arranged substantialy perpendicular to the direction of trabecular bone and cartilage endplate. The closer the endplate surface, the smaler trabecular bone was. Compared with the control group, these smal trabecular bones were thin and curved. Bone marrow cavity was oval. The degree of the connection between the trabecular bones is poor, reflecting the structural characteristics of significant osteoporosis. (3) It is indicated that weightlessness affected the biomechanical properties of rhesus lumbar motion unit.
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BACKGROUND:Deep vein thrombosis after total knee arthroplasty has attracted increasing attention in recent years,but how to detect deep vein thrombosis in the early time in clinical practice remains unclear.Whether it is necessary to perform type-B ultrasonic or other invasive examination in lower limbs has become a hot issue.OBJECTIVE:To explore the significance of D-Dimer and fibrin degradation products in the prediction of deep vein thrombosis after total knee arthroplasty.METHODS:56 patients received total knee arthroplasty were colected from Department of Orthopedics,The 306th Hospital of Chinese PLA,between December 2012 and February 2014.The D-Dimer and fibrin degradation products were dynamicaly monitored before operation and at 1,3,5,7,10 days post-operation.Al the patients received type-B ultrasonic examination in double lower limbs at 10 days post-operation,and divided into thrombus group and non-thrombus group.The D-Dimer and fibrin degradation products in the two groups were compared.RESULTS AND CONCLUSION:Deep vein thrombosis was found in 13 cases by ultrasonic-B postoperation,D-Dimer and fibrin degradation products showed no significant difference between the two groups at 1 week after operation (P＞0.05),but the difference was significant at 10 days (P＜0.01).D-Dimer and fibrin degradation products index should be monitored dynamicaly for at least 10 days after operation,which is helpful for the earlydiagnosis of thrombosis.
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BACKGROUND:Severe spinal angular kyphosis aggravated spinal cord injury and early degeneration, even caused incomplete paralysis or complete paralysis. Surgical treatment is the only solving approaches and method, but it is difficult, exhibits high risk, and easily affects postoperative complications. OBJECTIVE:To analyze the science and effectiveness of posterior vertebral column resection osteotomy combined with step correction in treatment of stiff angular kyphosis based on biomechanical principle. METHODS:A total of 90 cases underwent posterior vertebral column resection osteotomy combined with bilateral pedicle screw spinal cord gradual y shortening echelon tight closure and orthopedic fixation were selected, including 37 males and 52 females, at the average age of 47 years. Kyphotic angle, spinal sagittal imbalance, trunk side offset rate, operation time, intraoperative blood loss were compared and analyzed before and after treatment. RESULTS AND CONCLUSION:The kyphotic angles were 31°-138° (averagely 90.1°) preoperatively and 10°-90° (averagely 41.6°) postoperatively, with an improvement rate of 65%. The distance from C 7 plumb line to the S 1 upper edge was averagely 5.2 mm, with a correction rate of 73%. Intraoperative blood loss was 1 200-6 000 mL, averagely 2 089 mL. Operation time was 212-470 minutes, averagely 326 minutes. The patients were fol owed up for 20 to 35 months after the surgery. Osteotomy segments had achieved bone fusion in al patients, and no complications of spinal cord injury or orthopedic angle loss appeared. These data verified that in the accordance with cellbiomechanics and spinal biomechanical principles, bilateral pedicle screw spinal cord gradual y shortening echelon tight closure and orthopedic fixation protected utmost spinal cord cells against injury in the correction of thoracolumbar angular kyphosis. There is sufficient basis for cellphysiology and it accorded biomechanical and physiological characteristics. During the surgery, we should pay attention to protection and release of nerve root and avoid postoperative corresponding nerve root irritation. Ful fusion ensures kyphosis correction and avoids spine lateral offset, is an effective safeguard for the recovery of spinal function and postoperative orthopedic effect.
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BACKGROUND:The treatment difficulties of thoracolumbar angular kyphosis surgery are:low correction rate, hard to rebuild sagittal plane, easily induce neurological complications, postoperative loss of balance, high incidence of pseudarthrosis and postoperative loss of correction degree. OBJECTIVE:To explore the safety and efficacy of modified posterior vertebral column resection osteotomy and bilateral pedicle screw combined with echelon tight closure spinal cord technique and implant fixation for severe spinal angular kyphosis. METHODS:A total of 87 severe spinal angular kyphosis patients, 36 males and 51 females, who were treated in the Department of Orthopedics, the 306 Hospital of Chinese PLA from January 2006 to December 2013, were enrol ed in this study. They underwent posterior vertebral column resection, bilateral pedicle screw combined with echelon tight closure spinal cord, and implant fixation. Kyphosis, spinal sagittal imbalance, offset rate towards trunk side, operation time and intraoperative blood loss were observed before and after treatment. RESULTS AND CONCLUSION:The preoperative average kyphosis was 90.1° (31°-138°). The postoperative average kyphosis was 27.9° (15°-57°). The improvement rate was 76%. The improvement rate of trunk sagittal offset was 76%. Intraoperative blood loss was 800-3 000 mL, and average blood loss was 2 300 mL. The operation time was 5-7 hours, averagely 5.9 hours. Before treatment, two patients affected neurologic symptoms in double lower extremity, and their Frankel classification was grade C and became grade E after treatment. Al patients were fol owed up for 9-57 months. Bony fusion was achieved in al patients. No complications of spinal cord injury appeared, and no orthopedic angle missing occurred. These results indicate that during posterior vertebral column resection for treating severe angular stiffness of the thoracic kyphosis, blood vessels could be maintained greatly. Blood vessel injury-induced ischemic changes in spinal cord and ischemic reperfusion injury could be avoided. To reduce hemorrhage and to keep effective blood volume in patients with low body mass are effective for early recovery after treatment. Bilateral pedicle screw combined with echelon tight closure spinal cord technique greatly protected spinal cord cells against injury. We should pay attention to the protection and loose of nerve root to avoid postoperative nerve root irritation. Sufficient bone fusion ensures kyphosis correction, avoids spine lateral offset, and plays a key role in spinal function and postoperative orthopedic effect.
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BACKGROUND:Orthopedic osteotomy at the apex of kyphosis is best for treatment of ankylosing spondylitis from a biomechanical aspect, but there is a high risk for intraoperative spinal cord injury. OBJECTIVE:To explore the clinical efficacy of vertebral plate osteotomy+vertebra osteotomy+long-segment pedicle screw fixation in the treatment of ankylosing spondylitis with kyphotic deformity. METHODS:Thirty-six patients with ankylosing spondylitis were subjected to pedicle subtraction osteotomy and Smith-Peterson osteotomy, and then fol owed up for 3 months to 2 years. RESULTS AND CONCLUSION:After implantation, sagittal imbalance did not occur in 36 patients, and the improvement rate of sagittal imbalance was 64%. The improvement rates of thoracolumbar kyphosis and chin-brow vertical angle were 60%and 98%, respectively. The pain relief rate was 64%, and the Oswestry Disability Index was 95%. There were no pul ed nails, broken nails and broken robs after implantation. These findings indicate that the combination of selective osteotomy technique and long-segment internal fixation can achieve stable fixation effects, prevent sagittal imbalance, and avoid the occurrence of pul ing nails, breaking nails and breaking robs caused by osteoporosis.