Network meta-analysis of percutaneous vertebroplasty, percutaneous kyphoplasty, nerve block, and conservative treatment for nonsurgery options of acute/subacute and chronic osteoporotic vertebral compression fractures (OVCFs) in short-term and long-term effects.

BACKGROUND: Osteoporotic vertebral compression fractures (OVCFs) commonly afflicts most aged people resulting back pain, substantial vertebral deformity, functional disability, decreased quality of life, and increased adjacent spinal fractures and mortality. Percutaneous vertebral augmentation (PVA) included percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP), nerve block (NB), and conservative treatment (CT) are used for the nonsurgery treatment strategy of OVCFs, however, current evaluation of their efficacy remains controversial. METHODS AND ANALYSIS: A systematic literature search was carried out in PubMed, EMBASE, Web of Knowledge, and the Cochrane Central Register of Controlled Trials up to October 31, 2017. Randomized controlled trials (RCTs) were compared PVP, PKP, NB, or CT for treating OVCFs. The risk of bias for each trial was rated according to the Cochrane Handbook. Mean differences (MDs) with 95% confidence intervals (CIs) were utilized to express VAS (visual analog scale) outcomes. The network meta-analysis (NMA) of the comparative efficacy measured by change of VAS on acute/subacute and chronic OVCFs was conducted for a short-term (<4 weeks) and long-term (≥6-12months) follow-up with the ADDIS software. RESULTS: A total of 18 trials among 1994 patients were included in the NMA. The PVA (PVP and PKP) had better efficacy than CT. PKP was first option in alleviating pain in the case of the acute/subacute OVCFs for long term, and chronic OVCFs for short term and long term, while PVP had the most superiority in the case of the acute/subacute OVCFs for short term. NB ranks higher probability than PKP and PVP on acute/subacute OVCFs in short and long-term, respectively. CONCLUSIONS: The present results suggest that PVA (PVP/PKP) had better performance than CT in alleviating acute/subacute and chronic OVCFs pain for short and long-term. NB may be used as an alternative or before PVA, as far as pain relief is concerned. Various nonsurgery treatments including CT, PVA (PVP/PKP), NB, or a combination of these treatments are performed with the goal of reducing pain, stabilizing the vertebrae, and restoring mobility.

Bio-inspired energy-harvesting mechanisms and patterns of dynamic soaring.

Albatrosses can make use of the dynamic soaring technique extracting energy from the wind field to achieve large-scale movement without a flap, which stimulates interest in effortless flight with small unmanned aerial vehicles (UAVs). However, mechanisms of energy harvesting in terms of the energy transfer from the wind to the flyer (albatross or UAV) are still indeterminate and controversial when using different reference frames in previous studies. In this paper, the classical four-phase Rayleigh cycle, includes sequentially upwind climb, downwind turn, downwind dive and upwind turn, is introduced in analyses of energy gain with the albatross's equation of motions and the simulated trajectory in dynamic soaring. Analytical and numerical results indicate that the energy gain in the air-relative frame mostly originates from large wind gradients at lower part of the climb and dive, while the energy gain in the inertial frame comes from the lift vector inclined to the wind speed direction during the climb, dive and downwind turn at higher altitude. These two energy-gain mechanisms are not equivalent in terms of energy sources and reference frames but have to be simultaneously satisfied in terms of the energy-neutral dynamic soaring cycle. For each reference frame, energy-loss phases are necessary to connect energy-gain ones. Based on these four essential phases in dynamic soaring and the albatrosses' flight trajectory, different dynamic soaring patterns are schematically depicted and corresponding optimal trajectories are computed. The optimal dynamic soaring trajectories are classified into two closed patterns including 'O' shape and '8' shape, and four travelling patterns including 'Ω' shape, 'α' shape, 'C' shape and 'S' shape. The correlation among these patterns are analysed and discussed. The completeness of the classification for different patterns is confirmed by listing and summarising dynamic soaring trajectories shown in studies over the past decades.

Effect of intrathecal dexmedetomidine on spinal morphine analgesia in patients with refractory cancer pain.

BACKGROUND: Systemic administration of dexmedetomidine has been shown to reduce opioid consumption and improve analgesia satisfaction. The purpose of this study was to investigate the effect of intrathecal dexmedetomidine on spinal morphine analgesia in patients with refractory cancer pain. METHODS: A double-blinded crossover study was designed and performed. Patients were randomly allocated in one of the two phases. Phase M received intrathecal morphine administration. Phase M+D received intrathecal morphine plus dexmedetomidine administration. All patients were monitored for 7 days and crossed over to alternate phase for another 1-week observation. Daily average visual analog scale (VAS) pain score, pain frequency, sleep deprivation, daily morphine consumption, bolus dose injection times, and side effects were all recorded. RESULTS: Pain intensity and frequency were significantly decreased in both phases compared with baseline. Daily morphine consumption and bolus dose injection times during phase M+D were significantly decreased compared with phase M. The incidences of constipation were significantly reduced in both phases compared with baseline administration, but nausea and vomiting were significantly increased. No serious side effects such as respiratory inhibition were observed in this study. CONCLUSIONS: Intrathecal administration of dexmedetomidine and morphine reduced the morphine consumption in patients with refractory cancer pain. There were no serious side effects.