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Objective:To compare the restoration effects and mechanical reconstruction between different approaches in percutaneous kyphoplasty (PKP) through an in vitro mechanical experiment. Methods:T 7 to L 4 segments of adult male embalmed spinal specimens were selected for this experiment. Single vertebral specimens were randomly divided into 4 groups: unilateral angled approach group (Group A), unilateral transpedicular approach group (Group B), unilateral oblique approach group (Group C), and bilateral transpedicular approach group (Group D) ( n=10). The anterior and posterior edges of the vertebral body were measured, and the vertebral volumes were calculated and compared. After the model of osteoporotic vertebral compression fracture (OVCF) was established on a biomechanical machine, the anterior and posterior edges of the vertebral body were measured again. After the 4 groups of specimens were subjected to PKP via different approaches, Micro-CT examination of the vertebral bodies was conducted to measure the postoperative anterior and posterior edges of the vertebral body. The original strength and stiffness of the vertebral body, the stiffness after modeling, the postoperative strength, the postoperative stiffness on the puncture and contralateral sides, and postoperative overall stiffness were recorded. The distribution of bone cement in the vertebral body, recovery of anterior and posterior heights, strength, and stiffness were compared among the 4 groups. Results:There was no statistically significant difference in the vertebral volume among the 4 groups ( P>0.05). The amount of bone cement in group D was significantly larger than that in the other 3 groups ( P<0.05). There was no statistically significant difference among the 4 groups in terms of vertebral height recovery, original strength, original stiffness, stiffness after modeling, or postoperative overall stiffness ( P>0.05). There was no statistically significant difference between the postoperative strength and the original strength in the 4 groups ( P>0.05). The postoperative stiffness on the puncture side in the 4 groups and the postoperative stiffness on the contralateral side in groups A and D were significantly higher than those after modeling ( P<0.05), but there was no statistically significant difference in the contralateral stiffness in groups B and C between postoperation and post-modeling ( P>0.05). Conclusions:In PKP, the unilateral angled approach, unilateral transpedicular approach, unilateral oblique approach, and bilateral transpedicular approach all can effectively restore the height, strength and overall stiffness of the responsible vertebral body. The unilateral angled approach and the bilateral transpedicular approach can achieve balanced restoration of the stiffness on bilateral sides of the responsible vertebral body.
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Objective To investigate the clinical effect of posterior short-segment pedicle screw reduction and fixation without fusion in treatment of thoracolumbar mono-segmental compression fractures.Methods Thirty cases of thoracolumbar mono-segmental compression fractures admitted from January 2009 to February 2010 were assigned to single posterior pedicle screw fixation (screw group,n =15) and posterior pedicle screw fixation with posterolateral fusion (fusion group,n =15) according to random number table.Clinical results in the two groups were assessed based on Cobb' s angle,anterior vertebral body height ratio (％) and Oswestry disability index (ODI) before operation,after operation,prior to the removal of implant and at the latest follow-up.Results All the cases were followed up for average 24 months.Both operation time and blood loss were less in screw group than in fusion group [(76.58 ±12.67) min vs (116.29 ± 17.45) min,P ＜ 0.01 ; (287.54 ± 30.76) ml vs (480.34 ± 100.54) ml,P ＜0.01],whereas there were no statistical differences between the two groups in aspects of Cobb' s angle and anterior vertebral body height ratio before and after operation,prior to the removal of implant as well as at the latest follow-up.Moreover,no statistical difference of ODI was noted between the two groups prior to the removal of implant and at the latest follow-up.Conclusion Posterior pedicle screw fixation without bone grafting achieves similar effects with pedicle screw fixation with bone grafting.
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OBJECTIVE： To survey an evaluate the current situation and trend of the use of digestive system drugs.METHODS： To make a survey of the use of the above-mentioned drugs in 51 hospitals of four provinces in southwest China during the period 1999～2000 in respect to the sum of money of sales， main kinds， DDDs etc.and to analyse the clinical application of these drugs.RESULTS： As the sum of money for sales of the digestive system drugs， it was increased 42.08％ in 2000 compared with that in 1999.As the DDDs of the digestive system drugs， it is increased 8.85％ in 2000 compared with that in 1999.The average cost of DDD was 2.76 yuan in 2000 and 2.60 yuan in 1999.CONCLUSION： The digestive system drugs is an important kind of drug which has prospects of fast increase.