Minimally invasive pedicle screw fixation combined with percutaneous vertebroplasty for preventing secondary fracture after vertebroplasty.

BACKGROUND: Percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) could give rise to excellent outcomes and significant improvements in pain, analgesic requirements, function, cost, and incidence of serious complications for thoracolumbar osteoporotic vertebral compression fractures (VCFs). But some studies showed the recurrent fracture of a previously operated vertebra or adjacent vertebral fracture after PVP or PKP. The purpose of this study was to compare minimally invasive pedicle screw fixation (MIPS) and PVP with PVP to evaluate its feasibility and safety for treating acute thoracolumbar osteoporotic VCF and preventing the secondary VCF after PVP. METHODS: Sixty-eight patients with a mean age of 74.5 years (ranging 65 ~ 87 years), who sustained thoracic or lumbar fresh osteoporotic VCFs without neurologic deficits underwent the procedure of PVP (group 1, n = 37) or MIPS combined with PVP (group 2, n = 31). Visual analog scale pain scores (VAS) were recorded and Cobb angles, central and anterior vertebral body height were measured on the lateral radiographs before surgery and immediately, 1 month, 2 months, 3 months, 6 months, 1 year, and 2 years after surgery. RESULTS: The patients were followed for an average of 27 months (ranging 24-32 months). The VAS significantly decreased after surgery in both groups (P < 0.005). The central and anterior vertebral body height significantly increased (P < 0.005), and the Cobb angle significantly decreased (P < 0.05) immediately after surgery in both groups. No significant changes in both the Cobb angle correction and the vertebral body height gains obtained were observed at the end of the follow-up period in group 2. But the Cobb angle significantly increased (P < 0.005), and the central and anterior vertebral body height significantly decreased (P < 0.005) 2 years after surgery compared with those immediately after surgery in group 1, and there were five patients with new fracture of operated vertebrae and nine cases with fracture of adjacent vertebrae. CONCLUSIONS: MIPS combined with PVP is a good choice for the treatment of acute thoracolumbar osteoporotic VCF, which can prevent secondary VCF after PVP.

Energy-dependence of vibrational relaxation between highly vibrationally excited KH (X1Σ+, ν"=14-23) and H2, and N2.

Vibrational state total relaxation rate coefficients, k(ν") (M), for KH (ν"=14-23) by M=H(2) and N(2) have been investigated in an overtone pump-probe configuration. At ν"=14, 15, 16 and 17, the rate coefficients k(ν)(″) (M) increase linearly with vibrational quantum number. The region (ν"=18, 19, 20 and 21) where the dependence is much stronger than linear has significant contribution from multiquantum (Δν≥2) relaxation. For ν"=18, 19, 20 and 21, 0.25, 0.31, 0.38 and 0.31 of the initially prepared population undergo two-quantum (Δν=2) vibrational relaxation in KH (ν")+H(2) collisions. In KH (ν")+N(2), the time profile of ν"=14(15) after preparation of ν"=19(20) was measured. A clear bimodal distribution is observed. The time scale of the first peak is much shorter than the known collisional lifetimes of the intervening vibrational levels and thus a sequential single-quantum relaxation mechanism can be explicitly ruled out. Relaxation of KD with D(2) has been also investigated. The relaxation rate coefficients exhibit distinct maxima for both isotopes (KH and KD). We discuss possible explanation of the experimental results including mass effect, V-R energy transfer and V-V energy transfer.

[Vibration-vibration energy transfer between highly vibrational excited RbH and H2, N2].

Rb-H2 mixture was irradiated with pulses of 696.4 nm radiation from a OPO laser, populating 6D state by two-photon absorption. The vibrational levels of RbH(X1sigma+,v" = 0-2) generated in the reaction of Rb(6D) with H2. Vibrational-state-specific total-removal relaxation rate coefficients, k(v) (M), for RbH(X1sigma+, v" = 15-22) by M = H2 and N2 were investigated in a pump and probe configuration. By the overtone pumping with a cw diode laser, highly vibrational states v" = 15-22 of RbH in its ground electronic state were obtained. Another diode laser was used to probe the prepared vibrational state. The decay signal of laser induced time-resolved fluorescence from A 1sigma+ (v') --> X1sigma+ (v") transition was monitored. Based on the Stern-Volmer equation, the total relaxation rate coefficient k(v) (H2) were yielded. A plot of k(v) (H2 + N2) vs alpha (mole fraction H2) yields a line with a slope of k(v) (H2)-k(v) (N2) and an intercept of k(v) (N2). The values of k(v) (H2) obtained from the slope of the fitted lines compare well with determined values of the k(v) (H2) from the Sern-Volmer plots. At v" < 18, the rate coefficients k(v) (M) increases linearly with vibrational quantum number. This linear region is dominated by single quantum relaxation (deltav = 1) collisional propensity rules. The region (v" > or = 18) where the dependence is much stronger than linear shows significant contribution from multiquantum (deltav > or = 2) relaxation or resonant vibration-vibration energy transfer between highly vibrationally excited RbH and H2 or N2. For RbH(v") + N2 (0), we measured the time-profile of v" = 16 after preparation of v" = 21. A clear bimodal distribution was observed. The first peak is due to resonant vibration-vibration energy transfer: RbH (v" = 21) + N2 (0) --> RbH (v" = 16) + N2 (1). The much broader second peak, at longer time delays, is due to sequential single-quantum relaxation. Although the second process results in a distribution that is much more spread out in time, the peak height is in the same order of magnitude, indicating that the two processes are at least comparable in probability.

[Expression changes of genes related to calcium pathway in all-trans retinoic acid-induced differentiation of APL cells].

In order to investigate the role of calcium pathway in myeloid differentiation, the expression level of genes related to calcium pathway in all-trans retinoic acid (ATRA)-induced NB4 cell differentiation was detected by cDNA microarray, some of which were further confirmed by quantitative real time RT-PCR. At the same time, the expressions of these genes in NB4-R1 cells treated with ATRA and 8-CPT-cAM P alone or in combination, and in differentiation of primary cells from ATRA-induced newly diagnosed APL patients were detected by real time RT-PCR. The results showed that during differentiation of ATRA-induced NB4 cells, the expressions of genes related to calcium concentration had changed, the expression of downstream effectors in calcium pathway was up-regulated and confirmed by real time RT-PCR assay. The expression of genes related to calcium concentration did not change significantly when NB4-R1 cells were treated by ATRA or 8-CPT-cAMP alone, but expression changes of those genes were similar to the changes in ATRA-induced NB4 cell differentiation when NB4-R1 cells were treated by ATRA combined with 8-CPT-cAMP. In addition, the expression changes of those genes in ATRA-induced primary cells of patients with APL were also similar to changes in ATRA-induced NB4 cell differentiation. It is concluded that calcium pathway may be involved in ATRA-induced differentiation in APL cell.