In recent years, a variety of minimally invasive lumbar surgery techniques have achieved desirable efficacy, but some dispute remains regarding the advantages over open surgery. This study aimed to compare minimally i...In recent years, a variety of minimally invasive lumbar surgery techniques have achieved desirable efficacy, but some dispute remains regarding the advantages over open surgery. This study aimed to compare minimally invasive lumbar interbody fusion via MAST Quadrant retractor with open surgery in terms of perioperative factors, postoperative back muscle function, and 24-month postoperative follow-up results. Methods From September 2006 to June 2008, patients with single-level degenerative lumbar spine disease who were not responsive to conservative treatment were enrolled in this study. Patients were randomized to undergo either minimally invasive surgery （MIS, transforaminal lumbar interbody fusion via MAST Quadrant retractor, 41 cases） or open surgery （improved transforaminal lumbar interbody fusion, 38 cases）. Results The MIS group had longer intraoperative fluoroscopy time than the open surgery group, and the open surgery group had significantly increased postoperative drainage volume and significantly prolonged postoperative recovery time compared with the MIS group （P 〈0.05 for all）. MRI scanning showed that the T2 relaxation time in the multifidus muscle was significantly shorter in the MIS group than in the open surgery group at 3 months after surgery （P 〈0.01）. Surface electromyography of the sacrospinalis muscle showed that the average discharge amplitude and frequency were significantly higher in the MIS group than in the open surgery group （P 〈0.01）. The Oswestry disability index and visual analog scale scores were better at 3, 6, 12 and 24 months postoperatively than preoperatively in both groups. Both groups of patients met the imaging convergence criteria at the last follow-up. Conclusions MIS can effectively reduce sacrospinalis muscle injury compared with open surgery, which is conducive to early functional recovery. In the short term, MIS is superior to open surgery, but in the long term there is no significant difference between the two procedures.展开更多
The aim of this paper is to investigate the central limit theorems for asymptotically negatively dependent random fields under lower moment conditions or the Lindeberg condition. Results obtained improve a central lim...The aim of this paper is to investigate the central limit theorems for asymptotically negatively dependent random fields under lower moment conditions or the Lindeberg condition. Results obtained improve a central limit theorem of Roussas[11]for negatively associated fields and the main results of Su and Chi [18]. and also include a central limit theorem for weakly negatively associated random variables similar to that of Burton et al.[20].展开更多
In this paper,we calculated the spatial local-averaged velocity strains along the streamwise direction at four spatial scales according to the concept of spatial local-averaged velocity structure function by using the...In this paper,we calculated the spatial local-averaged velocity strains along the streamwise direction at four spatial scales according to the concept of spatial local-averaged velocity structure function by using the three-dimensional three-component database of time series of velocity vector field in the turbulent boundary layer measured by tomographic time-resolved particle image velocimetry.An improved quadrant splitting method,based on the spatial local-averaged velocity strains together with a new conditional sampling phase average technique,was introduced as a criterion to detect the coherent structure topology.Furthermore,we used them to detect and extract the spatial topologies of fluctuating velocity and fluctuating vorticity whose center is a strong second-quadrant event(Q2) or a fourth-quadrant event(Q4).Results illustrate that a closer similarity of the multi-scale coherent structures is present in the wall-normal direction,compared to the one in the other two directions.The relationship among such topological coherent structures and Reynolds stress bursting events,as well as the fluctuating vorticity was discussed.When other burst events are surveyed(the first-quadrant event Q1 and the third-quadrant event Q3),a fascinating bursting period circularly occurs:Q4-S-Q2-Q3-Q2-Q1-Q4-S-Q2-Q3-Q2-Q1 in the center of such topological structures along the streamwise direction.In addition,the probability of the Q2 bursting event occurrence is slightly higher than that of the Q4 event occurrence.The spatial instable singularity that almost simultaneously appears together with typical Q2 or Q4 events has been observed,which is the main character of the mutual induction mechanism and vortex auto-generation mechanism explaining how the turbulence is produced and maintained.展开更多
AIM:To give an overview of the literature on left-sided acute appendicitis (LSAA) associated with situs inversus totalis (SIT) and midgut malrotation (MM).METHODS:We present a new case of LSAA with SIT and a literatur...AIM:To give an overview of the literature on left-sided acute appendicitis (LSAA) associated with situs inversus totalis (SIT) and midgut malrotation (MM).METHODS:We present a new case of LSAA with SIT and a literature review of studies published in the English language on LSAA,accessed via PubMed and Google Scholar databases.RESULTS:Ninety-five published cases of LSAA were evaluated and a 25-year-old female,who presented to our clinic with left lower abdominal pain caused by LSAA,is reported.In the reviewed literature,fiftyseven patients were male and 38 were female with an age range of 8 to 82 years and a median age of 29.1 ± 15.9 years.Sixty-six patients had SIT,23 had MM,three had cecal malrotation,and two had a previously unnoted congenital abnormality.Fifty-nine patients had presentedto the hospital with left lower,14 with right lower and seven with bilateral lower quadrant pain,and seven subjects complained of left upper quadrant pain.The diagnosis was established preoperatively in 49 patients,intraoperatively in 19,and during the postoperative period in five;14 patients were aware of having this anomaly.The data of eight patients were not unavailable.Eleven patients underwent laparoscopic appendectomy,which was combined with cholecystectomy in two cases.Histopathological examination of the appendix specimens revealed adenocarcinoma in only two of 95 patients.CONCLUSION:The diagnosis of left lower quadrant pain is based on well-established clinical symptoms,physical examination and physician's experience.展开更多
Background： The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate th...Background： The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate the clinical feasibility of Mast Quadrant-assisted modified transforaminal lumbar interbody fusion （TLIF） with a small single posterior median incision. Methods： During the period of March 2011 to March 2012, 34 patients with single-segment degenerative lumbar disease underwent the minimally invasive modified TLIF assisted by Mast Quadrant with a small single posterior median incision （single incision group）. The cases in this group were compared to 37 patients with single-segment degenerative lumbar disease in the double incision group. The perioperative conditions of patients in these two groups were statistically analyzed and compared. The Oswestry Disability Index （ODI） scores, Visual Analog Scale （VAS） scores, and sacrospinalis muscle damage evaluation indicators before operation and 3, 12 months postoperation were compared. Results： A total of 31 and 35 cases in the single incision and double incision groups, respectively, completed at least 12 months of systemic follow-up. The differences in perioperative conditions between the two groups were not statistically significant. The incision length of the single incision group was significantly shorter than that of the double incision group （P 〈 0.01）. The ODI and VAS scores of patients in both groups improved significantly at 3 and 12 months postoperation. However, these two indicators at 3 and 12 months postoperation and the sacrospinalis muscle damage evaluation indicators at 3 months postoperation did not differ significantly between the two groups （P _〉 0.05）. Conclusions： Mast Quadrant-assisted modified TLIF with a small single posterior median incision has excellent clinical feasibility compared to minimally invasive TLIF with a double paramedian incision.展开更多
In 2007,Chen and Ng investigated infinite-time ruin probability with constant interest forceand negatively quadrant dependent and extended regularly varying-tailed claims.Following this work,the authors obtain a weakl...In 2007,Chen and Ng investigated infinite-time ruin probability with constant interest forceand negatively quadrant dependent and extended regularly varying-tailed claims.Following this work,the authors obtain a weakly asymptotic equivalent formula for the finite-time and infinite-time ruinprobability with constant interest force,negatively quadrant dependent,and dominated varying-tailedclaims and negatively lower orthant dependent inter-arrival times.In particular,when the claims areconsistently varying-tailed,an asymptotic equivalent formula is presented.展开更多
文摘In recent years, a variety of minimally invasive lumbar surgery techniques have achieved desirable efficacy, but some dispute remains regarding the advantages over open surgery. This study aimed to compare minimally invasive lumbar interbody fusion via MAST Quadrant retractor with open surgery in terms of perioperative factors, postoperative back muscle function, and 24-month postoperative follow-up results. Methods From September 2006 to June 2008, patients with single-level degenerative lumbar spine disease who were not responsive to conservative treatment were enrolled in this study. Patients were randomized to undergo either minimally invasive surgery （MIS, transforaminal lumbar interbody fusion via MAST Quadrant retractor, 41 cases） or open surgery （improved transforaminal lumbar interbody fusion, 38 cases）. Results The MIS group had longer intraoperative fluoroscopy time than the open surgery group, and the open surgery group had significantly increased postoperative drainage volume and significantly prolonged postoperative recovery time compared with the MIS group （P 〈0.05 for all）. MRI scanning showed that the T2 relaxation time in the multifidus muscle was significantly shorter in the MIS group than in the open surgery group at 3 months after surgery （P 〈0.01）. Surface electromyography of the sacrospinalis muscle showed that the average discharge amplitude and frequency were significantly higher in the MIS group than in the open surgery group （P 〈0.01）. The Oswestry disability index and visual analog scale scores were better at 3, 6, 12 and 24 months postoperatively than preoperatively in both groups. Both groups of patients met the imaging convergence criteria at the last follow-up. Conclusions MIS can effectively reduce sacrospinalis muscle injury compared with open surgery, which is conducive to early functional recovery. In the short term, MIS is superior to open surgery, but in the long term there is no significant difference between the two procedures.
基金Research supported by National Natural Science Foundation of China (No. 19701011)
文摘The aim of this paper is to investigate the central limit theorems for asymptotically negatively dependent random fields under lower moment conditions or the Lindeberg condition. Results obtained improve a central limit theorem of Roussas[11]for negatively associated fields and the main results of Su and Chi [18]. and also include a central limit theorem for weakly negatively associated random variables similar to that of Burton et al.[20].
基金supported by the National Basic Research Program of China(Grant No.2012CB720101)the National Natural Science Foundation of China(Grant No.10832001)the Opening Subject of State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences
文摘In this paper,we calculated the spatial local-averaged velocity strains along the streamwise direction at four spatial scales according to the concept of spatial local-averaged velocity structure function by using the three-dimensional three-component database of time series of velocity vector field in the turbulent boundary layer measured by tomographic time-resolved particle image velocimetry.An improved quadrant splitting method,based on the spatial local-averaged velocity strains together with a new conditional sampling phase average technique,was introduced as a criterion to detect the coherent structure topology.Furthermore,we used them to detect and extract the spatial topologies of fluctuating velocity and fluctuating vorticity whose center is a strong second-quadrant event(Q2) or a fourth-quadrant event(Q4).Results illustrate that a closer similarity of the multi-scale coherent structures is present in the wall-normal direction,compared to the one in the other two directions.The relationship among such topological coherent structures and Reynolds stress bursting events,as well as the fluctuating vorticity was discussed.When other burst events are surveyed(the first-quadrant event Q1 and the third-quadrant event Q3),a fascinating bursting period circularly occurs:Q4-S-Q2-Q3-Q2-Q1-Q4-S-Q2-Q3-Q2-Q1 in the center of such topological structures along the streamwise direction.In addition,the probability of the Q2 bursting event occurrence is slightly higher than that of the Q4 event occurrence.The spatial instable singularity that almost simultaneously appears together with typical Q2 or Q4 events has been observed,which is the main character of the mutual induction mechanism and vortex auto-generation mechanism explaining how the turbulence is produced and maintained.
文摘AIM:To give an overview of the literature on left-sided acute appendicitis (LSAA) associated with situs inversus totalis (SIT) and midgut malrotation (MM).METHODS:We present a new case of LSAA with SIT and a literature review of studies published in the English language on LSAA,accessed via PubMed and Google Scholar databases.RESULTS:Ninety-five published cases of LSAA were evaluated and a 25-year-old female,who presented to our clinic with left lower abdominal pain caused by LSAA,is reported.In the reviewed literature,fiftyseven patients were male and 38 were female with an age range of 8 to 82 years and a median age of 29.1 ± 15.9 years.Sixty-six patients had SIT,23 had MM,three had cecal malrotation,and two had a previously unnoted congenital abnormality.Fifty-nine patients had presentedto the hospital with left lower,14 with right lower and seven with bilateral lower quadrant pain,and seven subjects complained of left upper quadrant pain.The diagnosis was established preoperatively in 49 patients,intraoperatively in 19,and during the postoperative period in five;14 patients were aware of having this anomaly.The data of eight patients were not unavailable.Eleven patients underwent laparoscopic appendectomy,which was combined with cholecystectomy in two cases.Histopathological examination of the appendix specimens revealed adenocarcinoma in only two of 95 patients.CONCLUSION:The diagnosis of left lower quadrant pain is based on well-established clinical symptoms,physical examination and physician's experience.
文摘Background： The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate the clinical feasibility of Mast Quadrant-assisted modified transforaminal lumbar interbody fusion （TLIF） with a small single posterior median incision. Methods： During the period of March 2011 to March 2012, 34 patients with single-segment degenerative lumbar disease underwent the minimally invasive modified TLIF assisted by Mast Quadrant with a small single posterior median incision （single incision group）. The cases in this group were compared to 37 patients with single-segment degenerative lumbar disease in the double incision group. The perioperative conditions of patients in these two groups were statistically analyzed and compared. The Oswestry Disability Index （ODI） scores, Visual Analog Scale （VAS） scores, and sacrospinalis muscle damage evaluation indicators before operation and 3, 12 months postoperation were compared. Results： A total of 31 and 35 cases in the single incision and double incision groups, respectively, completed at least 12 months of systemic follow-up. The differences in perioperative conditions between the two groups were not statistically significant. The incision length of the single incision group was significantly shorter than that of the double incision group （P 〈 0.01）. The ODI and VAS scores of patients in both groups improved significantly at 3 and 12 months postoperation. However, these two indicators at 3 and 12 months postoperation and the sacrospinalis muscle damage evaluation indicators at 3 months postoperation did not differ significantly between the two groups （P _〉 0.05）. Conclusions： Mast Quadrant-assisted modified TLIF with a small single posterior median incision has excellent clinical feasibility compared to minimally invasive TLIF with a double paramedian incision.
基金supported by the National Science Foundation of China under Grant No. 10671139.
文摘In 2007,Chen and Ng investigated infinite-time ruin probability with constant interest forceand negatively quadrant dependent and extended regularly varying-tailed claims.Following this work,the authors obtain a weakly asymptotic equivalent formula for the finite-time and infinite-time ruinprobability with constant interest force,negatively quadrant dependent,and dominated varying-tailedclaims and negatively lower orthant dependent inter-arrival times.In particular,when the claims areconsistently varying-tailed,an asymptotic equivalent formula is presented.
