Purpose The aim of this study is to compare mTLIF vs. oTLIF with regard to peri-operative complications, operative time, estimated blood loss, fluoroscopic time, and the length of hospital stay. Methods The PubMed and EMBASE databases were searched for relevant articles reporting patients undergoing TLIF, and a comparison between mTILF and oTLIF was performed. The database included patient demographic information, complications, operative time, fluoroscopic time, and the length of hospital stay. Results Fourteen studies were included in this systematic review. The total number of subjects included was 901, of which 455 underwent mTLIF (50 %) and 446 underwent oTLIF (50 %). The operating time for the mTLIF was ranged from 116 to 390 minutes, compared with 102 to 365 minutes for oTLIF, the operating time tended to be longer in the mTLIF group than the oTLIF group. The estimated blood loss was lower in the mTLIF group, ranging from 51 to 578 ml in mTLIF and 225 to 961 ml in oTLIF, respectively. Length of hospital stay was short for the mTLIF with a 2.3 to 10.6 days hospitalization compared to 2.9 to 14.6 days for oTLIF. However the fluoroscopic time was consistently higher in the mTLIF group with a 49 to 106 seconds of fluoroscopy compared to 16.4 to 44 seconds for oTLIF. The complications divided into technical complications and infection complications. The main technical and infection complications included dural tears, screw malposition, and wound infection. Systemic complications included pneumonia, urinary tract infection, and DVT. The numbers of patients with complication was 54 out of 455 (11.87 %) in the mTLIF, and 64 out of 446 (14.35 %) in the oTLIF. Conclusion The review shows mTLIF offers several potential advantages in reducing blood loss and the length of hospital stay, especially lowering the complication rates for patients compared with oTLIF. However, it required much more operative time and radiation exposure. Class I evidence and highquality randomized controlled trials are needed for further study. Keywords Complications . Minimally invasive spine surgery . Transforaminal lumbar interbody fusionTransforaminal lumbar interboby fusion (TLIF) has been widely performed for degenerative lumbar disease since Harms [1] popularized the procedure. It provides circumferential spinal fusion, restores disc height, and maintains the normal lordosis of the lumbar spine. Due to these advantages and good fusion rates in 95 % [2-6], TLIF has been proven as a safe and effective technique in the past three decades. However, extensive paravertebral muscle stripping and retraction during the procedure to obtain an adequate surgical field causes significant soft tissue injury. This iatrogenic

The effect of elevated airflow on sleep quality was investigated with 18 elderly. Three airflow conditions were set: ceiling fan/30°C/max.0.8 m/s and mean 0.7 m/s, task fan/30°C/max.0.8 m/s and mean 0.6 m/s, and thermally neutral /27°C/0.2 m/s. Sleep quality was evaluated objectively by analysis of electroencephalogram signals that were continuously monitored during the sleeping period. Urinary cortisol concentrations were analyzed to measure the activity of sympathetic nervous system. No significant difference in sleep quality, thermal comfort, or cortisol concentration was found between the ceiling fan and the neutral condition. The duration of total sleep time decreased by 35 minutes, the duration of REM sleep decreased by 15 minutes, and the cortisol concentration in the morning increased by 50 ng/mL in the task fan than the other two conditions. Compared with ceiling fan, less heat load was removed in the task fan condition, possibly due to the lower air speed. This study shows that even small heat load led to reduced sleep quality and overactive sympathetic nervous system of the elderly. By supplying an airflow of 0.8 m/s evenly over the human body, the elderly could maintain sleep quality and thermal comfort at an air temperature that was 3 K higher than the neutral temperature.

In this study, a novel concept has been developed as a cyclical spacing-change method to produce periodic varied structural composite yarn. Geometrical analysis indicated that the cyclical change of spacing between filaments and the strand altered the yarn formation zone shapes from corefil to sirofil, causing cyclic yarn structure variations from the hairy core–sheath (corefil section) to the smooth spiral filament wrapping (sirofil section). A mechanical analysis revealed the corefil section with more twists was thinner than the sirofil section with fewer twists. Specifically, the cross-sectional diameter performed gradual periodic changes from the thick sirofil section to the thin corefil section. Then, an eccentric godet wheel device was used to conduct confirmatory experiments. Besides validating the theoretical analysis, the experimental results also showed that the novel concept yarn had the minimum hairiness and medium irregularity and strength after comparisons with sirofil and corefil yarns.

The aerodynamics of a cycloidal propeller operating in hovering flight is systematically studied using numerical method. By solving the time-dependent incompressible Navier–Stokes equations and using a dynamic mesh technique, the complex unsteady flow field around the cycloidal propeller and the time-varying aerodynamic forces are investigated. The wake flow deflection can be observed in the flow field of the cycloidal propeller, which results in a deflection of the thrust. Strong downwash around cycloidal propeller and unsteady interference between blades are induced by the rotation and pitch motion of the blade. The instantaneous vertical, horizontal and resultant thrusts fluctuate cyclically with the azimuths in a pattern similar to sinusoid, and although the direction of instantaneous resultant thrust varies in a comparatively large region during rotating, the direction of averaged resultant thrust produced in each revolution is almost constant at different rotation speeds. This is beneficial to the flight stability and maneuverability of a cyclogyro. When one blade moves upward, the aerodynamic forces of the blade are much higher than that produced when moving downward. With the increase of the blade number, the unsteady interference between blades and the wakes of other blades tend to be stronger, producing great effects on aerodynamic forces of the blades as well as the aerodynamic performance of cycloidal propeller.

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