Establishment And Preliminary Application Of Bone Cement Diffuse Volume In Percutaneous Vertebroplasty

Part I The relationship between injected cement volume and clinical efficacy of percutaneous vertebroplasty【objective】To investigate the relationship between injected cement volume and clinical effiacy of percutaneous vertebroplasty for osteoporotic vertebral compression fracture retrospectively.【methods】From May 2003 to March 2009, percutaneous vertebroplasty was performed on 87 vertebrates of 56 patients with osteoporotic vertebral compression fracture. All the patients were examined by BMD(bone mineral density),X-ray, pain scale and changes of radiology before surgery was measured, Including Visual Analog Scale, ODI index, the height of anterior,middle,posterior part of the vertebrates on the lateral position X-ray film, angle of kyphotic deformity. Compared the pain scale and radiological changes before and after operation.26 months of follow-up was performed in average. Comparison of statistical analysis was used in order to evaluated the clinical effiacy of percutaneous vertebroplasty.【results】56 patients were performed successfully,there is no exiting symptom getting worse or neurological symptoms or serious complications occurred during or after the surgery. 26 months of follow-up was acquired in average. Pain obviously relief after the surgery, the VAS scale changed from(7.2±1.7)to(2.3±1.1),the difference is significantly different (P < 0.05 ) , ODI score changed from (64.8±1.1)% to (41.1±1.0)%,the difference is statistically different (P<0.05).Pain relief between bone cement fill rate 1,2,3 in each group was not statistically significant (P>0.05), shows the amount of bone cement injected dose not correlate with pain relief. The height of anterior part is (14.7±4.2)mm,before PVP and (16.2±3.9)mm after PVP, the height of middle part is (11.6±3.6)mm, (14.5±3.8) before and after PVP.the statistics analysis showed significant difference (P<0.05). The height of the posterior part of the vertebrates is (22.1.5±5.3) mm and(23.7±2.6)mm, shows no evident differences(P>0.05). The kyphotic angle is(21.7±5.9)o,(16.6±5.2)o before and after PVP, The change of kyphotic angle showed significant difference (P<0.05). Pearson's analysis was used to analysis the height of different part of the vertebrates. Bone cement injected volume was correlated with the change of the anterior part and middle part of the vertebrates(p<0.01). There is no correlation between injected volume and the height of the posterior part.【conclusion】1. Percutaneous vertebroplasty effectively relief pain course by osteoporotic vertebral compression fracture, enhance the mechanical property of the vertebral body, restore stability of vertebral body.2. certain range of bone cement volume injected was positively correlated with the recovery of anterior,middle part,kyphosis angle of the vertebrates.Part II Establishment of the concept of diffuse volume and preliminary digital research【objective】Establish the concept of the diffuse volume of bone cement, studying the factors controlling the diffuse volume for the purpose of improving the efficacy of percutaneous vertebroplasty, provide theoretical support the reduction of cement extravasation. 【methods】56 CT scan images data had acquired after PVP. The image data transfer into DICOM format, the datd was then brought into the Vitrea 4.0 workstation. Calculating the cement diffuse volume by the Calculated 3D Function support by Vitrea workstation. Comparison of statistical analysis was used between injected cement volume and diffuse volume. Using manual method to outlining the scope of bone cement diffused in the DICOM format, finally application the Calculate 3D function provided by the software to calculate the diffuse volume of the vertebrates. According to the density of the bone cement in the vertebrae, CT value was seted (1000-3000), calculate the injected cement volume; bone cement injected volume were statistically compared with diffuse volume.【results】56 CT datds were calculated. The injection volume of the cement: T10(2941.7±0.1)mm3, T1(12897.5±0.2)mm3,T1(25813.1±1.7)mm3,L(13127.1±0.7)mm3,L(24373.4±2.5)mm3 ;Injected volume: T1(01242.8±0.4)mm3,T1(11464.2±0.1)mm3,T12(1121.7±0.7)mm3,L1(1475.3±1.8)mm3,L2(3118.6±1.7)mm3. Comparison of statistical analysis was used to evacuated the difference between Cement injection volume and diffusion volume. The differences were statistically significant(P<0.05). Pearson's analysis was used to analysis between the bone mineral density and diffuse volume, and it is negative correlation【conclusion】1. Diffuse volume is a different notion from Compare with injection volume, diffuse volume is a more accurate indicator reflect the distribution of the bone cement in the vertebal body;2. Diffuse volume is associated with bone mineral density, in the same injection pressure, the higher bone mineral density, the larger diffuse volume, the smaller volume of cement is needed. the lower bone mineral densit, the smaller diffuse volume, the larger volume of cement is needed.