What are the Risk Factors for Residual Pain After Percutaneous Vertebroplasty or Kyphoplasty? A Meta-Analysis.

BACKGROUND: Although many risk factors for residual pain following percutaneous vertebroplasty or kyphoplasty (PVP or PKP) have been reported in many studies, research methods and cohorts differ greatly. A previous meta-analysis identified patient- and operation-specific risk factors for residual pain. This study aimed to examine the available data and identify significant risk factors for residual pain after PVP or PKP. METHODS: PubMed, EMBASE, Web of Science, and the Chinese Wanfang Database were searched for relevant research in English and Chinese, and full-text publications including patients with and without residual pain were compared. Only studies presenting odds ratios from multivariate analysis of residual pain data were considered. To evaluate the impact of the results of the selected articles, Review Manager 5.4 was used. RESULTS: Twelve publications including a total of 3120 patients met the requirements. The meta-analysis examined 10 factors associated with residual pain and categorized them as either patient- or operation-associated factors. Thoracolumbar fascia injury, intravertebral vacuum cleft, depression, and number of fractured vertebrae were all significant patient-associated parameters for residual pain. Significant operation-associated risk factors included bone cement distribution and intraoperative facet joint injury. CONCLUSIONS: In this meta-analysis, we identified several significant risk factors for residual pain after PVP or PKP. These findings may be helpful for patient counseling and surgical planning.

The role of isolated Cu2+ location in structural stability of Cu-modified SAPO-34 in NH3-SCR of NO.

In this study, three different methods (ion exchange, wet mixing and impregnation) were employed to prepare Cu-modified SAPO-34 molecular sieves. All these freshly prepared catalysts showed excellent activities towards the selective catalytic reduction (SCR) of NO with NH3 (NH3-SCR) no matter which preparation method was used. However, hydrothermal ageing significantly reduced the catalytic activities of those catalysts prepared by the wet-mixing and impregnation methods, respectively. The results of X-ray powder diffraction, H2-TPR and electron paramagnetic resonance measurements for these catalysts suggested that the decrease in catalytic activity may be attributed to the migration of Cu2+ ion to the centre of the hexagonal prism (site III), the formation of CuxOy and the collapse of the molecular framework during hydrothermal ageing. The degrees of structural collapse of each Cu-modified molecular sieve were different, probably due to Cu2+ species in different sites (in the ellipsoidal cavity (site I) for ion-exchange sample, near the eight-ring window (site IV) for the wet-mixing and impregnation samples). Cu2+ located at site I was more stable than that located at site IV.