[Cement leakages in percutaneous vertebroplasty:analysis of postoperative computed tomography].

OBJECTIVE: To evaluate the influencing factors of cement leakage in vertebroplasty for the treatment of osteoporosis vertebral compression fracture (OVCF) and vertebral metastases (VM). METHODS: Retrospective analysis was conducted for 653 vertebrae in 356 patients undergoing vertebroplasty at our hospital from May 2007 to January 2011. 251 cases had 438 vertebrae with painful OVCF while 105 cases had 215 vertebrae with VM. Pre-operative computed tomography (CT) was performed to determine the presence of cortical defects or osteolysis and within 3 days after PVP to observe the distribution of polymethylmethacrylate (PMMA) in vertebrae and whether leakage occurred. Volume of PMMA injected into each vertebral body and types of cement leakage were compared between the OVCF and VM groups by Z test or χ². The correlation between cortical defects and cement leakages around vertebrae was assessed with Pearson correlation coefficient. RESULTS: The successful rate of PVP was 100%. The mean volume of PMMA injected into each vertebra was (5.0 ± 2.0) ml and (4.0 ± 1.7) ml in the OVCF and VM groups respectively (P < 0.05). Asymptomatic PMMA leakage was demonstrated by CT in 93 vertebrae (21.2%) in the OVCF group and in 53 vertebrae (28.8%) in the VM group respectively (P < 0.05). Cement leakages into disk were found in 58 vertebrae in the OVCF group and 16 vertebrae in the VM group respectively (P = 0.025). Cement leakages into paravertebral vein were found in 12 vertebrae in the OVCF group and 26 vertebrae in the VM group respectively (P < 0.0001). Correlation was found between cortical defects and cement leakage into paravertebral soft tissues in the OVCF group (r = 0.14) or in the VM group (r = 0.27), between end-plate defects and cement leakage into disk in the OVCF group (r = 0.29) or in the VM group (r = 0.31). CONCLUSION: As a common occurrence in vertebroplasty, cement extravasation is well-tolerated in most patients. It occurs more frequently in the patients with VM than those with OVCF, especially in cases of leakage into paravertebral vein. Cement leakage into disc or paravertebral soft tissue is predisposed in vertebrae with end plate, cortical defects or osteolysis.

[Value of intraosseous venography in percutaneous vertebroplasty for treatment of symptomatic vertebral hemangiomas].

OBJECTIVE: To evaluate the clinical efficacy of percutaneous vertebroplasty (PVP) in patients with symptomatic vertebral hemangiomas and determine whether prior intraosseous venography decreases extravertebral leakage of PMMA and improves clinical outcomes in these procedures. METHODS: Retrospective review was conducted on 45 consecutive patients with 53 symptomatic vertebral hemangiomas associated with chronic pain (all cases) or paralysis caused by spinal cord compression (1 case) or vertebral compression fractures (3 cases) treated with PVP at our institution to define two populations. Group A consisted of 27 vertebral hemangiomas in 23 patients who underwent intraosseous venography before injection polymethylmethacrylate (PMMA). Group B consisted of 26 vertebrae in 22 patients who underwent injection PMMA without prior venography. CT was done 1 to 3 days after PVP to observe PMMA distribution in vertebrae and whether leakage. Clinical outcomes, included pain relief, leakage of PMMA, volume of PMMA injected, expense and X-ray exposure times in each vertebral body, were compared in the two groups by using χ(2) or t test. RESULTS: No significant difference was seen between the groups with respect to age, sex, the number of treated vertebrae, or preprocedural degrees of pain. The successful rate of technique of PVP was 100%. The mean volume of PMMA injected in each vertebra was 3.96 ml. CR, PR and NR was obtained respectively 84.5%, 13.3% and 2.2% during 6 months to 5 years of follow-up expect one case had unrelieved pain in group A. At 6 months after PVP, 22 cases (95.7%) in group A and 22 cases (100%) in group B achieved adequate pain relief (P = 0.323). 6 vertebrae (6/27) in group A and 2 vertebrae (2/26) in group B with asymptomatic leakage of PMMA were demonstrated by CT (P = 0.140). The mean volume of PMMA injected in each vertebra was 3.70 ml in group A and 4.23 ml in group B (P = 0.157). The mean expense of each vertebra was ¥7.24 × 10(3) in group A and ¥5.84 × 10(3) in group B (P = 0.000), the mean decreases were ¥1.4 × 10(3) in group B than group A. The mean X-ray exposure times on each vertebral body was 13.28 minutes in group A and 8.78 minutes in group B (P = 0.000), the mean decreases were 4.5 minutes in group B than group A. CONCLUSIONS: PVP is an effective and safe procedure for treating symptomatic vertebral hemangiomas. Prior intraosseous venography does not significantly improve the effectiveness or safety of PVP for vertebral hemangiomas performed by qualified, experienced operators, on the other hand, it increases the expense and X-ray exposure times of PVP.

Nomogram for Predicting Intradiscal Cement Leakage Following Percutaneous Vertebroplasty in Patients with Osteoporotic Related Vertebral Compression Fractures.

BACKGROUND: Intradiscal cement leakage (ICL) is a common complication following percutaneous vertebroplasty (PVP). However, the risk factors for such a complication are under debate and there is no accurate predictive nomogram to predict ICL. OBJECTIVES: To establish an effective and novel nomogram for ICL following PVP in patients with osteoporotic-related vertebral compression fractures (OVCFs). STUDY DESIGN: This was a retrospective study approved by the Institutional Review Board of our institution. SETTING: This study consists of patients from a large academic center. METHODS: Patients with OVCFs who underwent their first PVP in our department between January 2007 and December 2013 were included in this study. All the potential risk factors of ICL after PVP were recorded. Univariate and multivariate analyses were used to identify the independent risk factors. The nomogram was then created based on the identified independent risk factors. RESULTS: A total of 241 patients and 330 vertebrae were included. The mean age of the patients was 73.5 (SD 7.9) years old, and the mean number of treated vertebrae was 1.4 per person. ICL was observed in 93 (28.2%) of the treated vertebrae. Greater fracture severity (P = 0.016), cortical disruption of the endplate (P < 0.0001), absence of Kummell's disease (P = 0.010), and higher computed tomography (CT) values (P = 0.050) were the independent risk factors for ICL. LIMITATIONS: The main limitation of this study is that it is a retrospective study. CONCLUSION: Greater fracture severity, cortical disruption of the endplate, absence of Kummell's disease, and higher CT values are the independent risk factors for ICL. The novel nomogram gives an accurate prediction of ICL.

ANVCFV Score System: Assessment for Probability of New Vertebral Compression Fractures after Percutaneous Vertebroplasty in Patients with Vertebral Compression Fractures.

BACKGROUND: Percutaneous vertebroplasty (PVP) is widely used for the treatment of painful vertebral compression fractures (VCFs). However, new VCFs occur frequently after PVP. OBJECTIVES: We aim to establish an objective risk score system to assess the possibility of new vertebral fractures in patients with VCFs undergoing PVP. STUDY DESIGN: This study was a retrospective study, and it was approved by the Institutional Review Board of our 2 institutions. SETTING: This study consists of patients from 2 large academic centers. METHODS: Patients with VCFs who underwent their first PVP and met the inclusion criteria between January 2007 and December 2013 at Hospital A (training cohort) and Hospital B (validation cohort) were included. In the training cohort, the independent risk factors for new VCFs after PVP were identified by multivariate stepwise backward Cox regression analysis from the risk factors selected by univariate analysis and Harrell's C-statistics and used to develop the score system (assessment for new VCFs after PVP [ANVCFV]) to predict the probability of new VCFs. RESULTS: In total, 397 patients (training cohort: n = 241; validation cohort: n = 156) were included in this study. In the training cohort, the ANVCFV score was developed based on 5 independent risk factors for the new VCFs after PVP, including lower computed tomography (CT) values, pre-existing old VCFs, intradiscal cement leakage, more than one vertebra treated, and superior or inferior marginal cement distribution in the vertebra. The patients were divided into 2 groups by the ANVCFV score of -1.5 to 8.5 vs. > 8.5 points in the probability of new VCFs (median fracture-free time: 1846 vs. 732 days; P < 0.001) in the training cohort. The accuracy of this score system was 77.4% for the training cohort and 85.3% for the validation cohort. LIMITATIONS: The main limitations of this study are that it is a retrospective study and that there is a significant difference of the treated vertebrae of PVP per session between the 2 cohorts. CONCLUSION: Patients who underwent their first PVP with an ANVCFV score > 8.5 points may exhibit an increased chance of suffering from new VCFs.

A simplified method of opacifying and mixing acrylic cement for percutaneous vertebroplasty: a clinical and in vitro study.

The objective of this study was to simplify the opacifying mixing process of the bone cement and contrast used for percutaneous vertebroplasty (PVP). We performed a biomechanical study of polymethyl methacrylate (PMMA) (Corinplast 3) using three different mixtures of PMMA, monomer, and contrast: group I, 2:1; group II, 3:2; group III, 3:2:1 ratio of powder/monomer/iodinated contrast (Omnipaque). In vitro biomechanical testing of ultimate compressive strength was carried out in all samples. Following the conclusion of a proper bone cement mixture regimen drawn from the in vitro study, PVP was performed in 125 patients: 58 with cancer, 12 with hemangioma, and 54 with osteoporotic fracture. The ultimate compressive strength in group III was decreased by 38% compared to groups II and I. Proper fluoroscopic visualization was achieved in all PVP procedures using this mixture. There were no major complications associated with injection of the cement mixture. Complete (CR) and partial response (PR) was obtained in 64% and 32.8%, respectively. No further vertebral collapse occurred during follow-up. The regimen using iodinated contrast for cement visualization during PVP provides a simple and convenient new method for mixing. Although the biomechanical strength is altered by the contrast medium added, it seems insignificant in clinical practice based on the authors' limited experience.