Surgical strategies for peripheral nerve schwannoma based on the intraoperative neurophysiological monitoring

Objective:To present our classification for peripheral nerve schwannomas as well as explore the surgical strategies and operative management of peripheral nerve schwannomas based on the intraoperative neurophysiological monitoring(INM)technique and to decrease the risk of postoperative neurological deficits in the management of these schwannomas.Materials and methods:A retrospective study was conducted on 92 cases of peripheral nerve microsurgery performed,using the INM technique.We also made the classification for peripheral nerve schwannomas into two types according to operative findings and proceeded corresponding surgical strategies.Results:All tumors were removed completely under microscopy and INM.Three patients developed residual neurological deficits at final follow-up.There were different results about temporary(18/92,19.6%)and permanent(3/92,3.3%)neurological deficits.The incidence of temporary and permanent neurological deficits in type II group was significantly higher than that in type I group(p<0.01).The incidence of permanent neurological deficits in larger size tumors was significantly higher than that of smaller size(p<0.01).Conclusions:We made the classification for peripheral nerve schwannomas according to operative findings based on INM that is helpful to our surgical strategies.Intracapsular enucleation was the preferred strategy with satisfactory results and low risk of nerve injury.The size and location of tumors seem to be related to the risk of fascicular injury.

Large eddy simulation study on drag reduction performance of array-based plasma synthetic jet actuators

Large Eddy Simulation(LES)is first used to investigate the drag reduction effect of an array-based configuration of Plasma Synthetic Jet Actuators(PSJAs)on a hemisphere in supersonic inflow,and analyze the effect of energy allocation and array angle on the drag reduction performance of opposing Plasma Synthetic Jet(PSJ)in this paper.Numerical simulation results have been compared with experimental data,confirming the validity of the simulation method.The results show that different energy allocations have a significant effect on the drag of the hemisphere.However,the effect of the change in array angle on the drag of the hemisphere is not as noticeable as the effect caused by energy allocation.Interference regions between the two PSJAs occur,which undermine the effectiveness of drag reduction.High Turbulent Kinetic Energy(TKE)regions primarily concentrate on the core region of the jet and downstream of the bow shock.The influence of the array angle on TKE is most evident in the downstream region of the exits of the PSJs on both sides.Temporal evolution of the coherent structures reveals that as the PSJ intensity decreases,the largescale vortices progressively break up into smaller-scale vortices,and energy is also transferred from large-scale structures to small-scale structures.

Trailing-edge shock loss control with self-sustaining synthetic jet in a supersonic compressor cascade

To effectively reduce the loss of strong shock wave at the trailing edge of the supersonic cascade under high backpressure,a shock wave control method based on self-sustaining synthetic jet was proposed.The self-sustaining synthetic jet was applied on the pressure side of the blade with the blow slot and the bleed slot arranged upstream and downstream of the trailing-edge shock,respectively.The flow control mechanism and effects of parameters were investigated by numerical simulation.The results show that the self-sustaining synthetic jet forms an oblique shock wave in the cascade passage which slows down and pressurizes the airflow,and the expansion wave downstream of the blow slot weakens the shock strength which can effectively change the Mach reflection to regular reflection and thus weaken the shock loss.And the suction effect can reduce loss near blade surface.Compared with the baseline cascade,the self-sustaining jet actuator can reduce flow losses by 6.73%with proper location design and vibration of diaphragm.