Different Ways Of Bone Cement To Strengthen For Osteoporosis Vertebral Pedicle Screw Placement Of Biomechanical Study

BackgroundAs human aging stage, patients with spinal degeneration is also increasing year by year, including osteoporosis patients are the most common.Osteoporosis (osteoporosis, OP), is the performance of a clinically as bone and trabecular bone mineral content reduction damage, accompanied by an increase in bone fragility systemic bone disease, is caused by a variety of reasons series bone disease. The clinical features of systemic bone pain, easy to fracture, reducing the amount of bone tissue.By primary and secondary causes of which were primary: juvenile adult type, menopause, senile. Our senile osteoporosis, more and more patients, with diseases of the spine vertebral lesions associated with senile osteoporosis also highlighted significant problems, OP patients with the most common and most serious complications of fractures and osteoporosis in elderly patients with osteoporotic vertebral fractures (OVCF) is the most common.Superior to conventional screw-rod system, pedicle screws for posterior spine stable gold standard. At present, the most commonly used in spinal surgery with posterior spinal fixation method is to pedicle screw fixation systems, which are easy to operate, the three-dimensional fixed, reset, etc.For the stability of the spine, bone-loose screw interface is a common complication, especially for elderly patients with osteoporosis. For patients with senile OP, osteoporosis affects ordinary pedicle screw holding power, holding power will usually decline, the consequences can cause instability pedicle screw loose, pull, etc., and cause of spinal fractures and fixation failure, etc., so the fixed effects reach the fixation requirement. Therefore, how to improve the pedicle screw fixation strength in osteoporotic vertebral spine surgery has become a major challenge. Generally increases the strength of pedicle screw fixation method is as follows:1. To enhance the pedicle screws in the bone friction, is about the screw entry point Shaopian outside.2. appropriate increase in the diameter of the screw.3. Application of the expansion pedicle screws.4. Strengthen pedicle screw fixation system fixed Methods posterior spinal instrumentation.5. After a small amount of bone fragments along the pedicle screw path screwed into the pedicle screws.6. injectable bone cement pedicle screw applications. Currently using bone cement augmentation of pedicle screw fixation on the clinical way, namely bone cement augmentation of pedicle screw screw channel and injectable bone cement screw, and yet the difference between the two aspects of the mechanical stability is not clear, the subject of a study around this problem.ObjectiveStrengthening axial pedicle screw pull biomechanical testing experiment in different ways, ways to strengthen the relationship less pull-out strength of the screws, the difference between the value of the stiffness and energy absorption, bone density and maximum pullout force.To investigate the stability and effectiveness of the injectable bone cement osteoporotic vertebral pedicle screws, and provide the basis for the clinical application of basic researchMethodUsing eight dry aged spine specimens were randomly selected sample, excluding tumors, fractures and pathological changes, such as specimens, Based on bone mineral density (BMD) measurements confirmed the diagnostic criteria for osteoporosis, Sealed and stored at room temperature selected lumbar vertebrae, All experiments were osteoporotic vertebral mechanical model consistent taxidermy, vertebral biomechanics, mechanical properties, load measurement methods, etc., were randomly divided into A, B, C, D, etc.4 groups of 20 vertebrae specimens are:simple pedicle screw group (control group), thickening of the pedicle screw group, concrete nails bone augmentation group, injectable bone cement pedicle screw group, Observation of C, D groups of bone cement leakage were measured axial pull biomechanical experimentsResult1. During the Pedicle screw and pin tract prefabricated process, it’s not occur pedicle fracture, rupture, perforation vertebral, in direct vision and X-ray examination found that the injectable bone cement under the pedicle screw group and no leakage of bone cement, bone concrete nails augmentation group see three vertebral bone cement leakage (30%).2. Maximum pullout strength There were significant differences (p<0.001) between any two groups.91% increase in group D than in group A,61% increase in group C than in group A, 21%increase in group B than in group A,40% increase in group C than in group B, D group than in group C increased by 30%.3. Stiffness A, C showed no significant difference (p> 0.05),Compared between the B, D groups and A, C groups, There were significant differences (p<0.05),Group B and D between the two groups was significant difference (p<0.05).4. Energy Absorption There were no significant differences (p> 0.05) between the A, B, C in any two groups, there is a significant difference (p<0.05) with the D group.5. The maximum pull-out strength and BMD To a certain extent, the screw maximum output with the increase of BMD, pull the largest output and BMD have positive correlation.ConclusionThrough different ways of bone cement to strengthen screw biomechanical study, For osteoporosis vertebral body and bone masonry nail reinforcement and injectable bone cement pedicle screws can significantly increase the stability of the screw, but injectable bone cement pedicle screws biomechanical stability of the best, and it can reduce the risk of leakage of bone cement. In clinical application, provided the foundation for basic research.