***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background High morbidity rates related to anastomotic leakage and other factors restrict the application of laparoscopic rectal excision . The aim of the present study was to assess the effect of left colonic artery ( LCA ) preservation on postoperative complications after laparoscopic rectal excision . Methods Data from 888 patients from 28 leading hospitals in Japan who underwent laparoscopic-assisted sphincter-preserving resection of middle and low rectal cancers between 1994 and 2006 were analyzed . The effects of LCA preservation were analyzed among all anterior resection ( AR ) cases ( n = 888 ) and among AR cases with radical lymph node excision ( n = 411 ) . Results Among all AR cases , the tumor size , number of lymph nodes collected with evidence of metastasis , TNM factor , and TNM staging were smaller in the LCA preservation group . Regarding complications , the rate of anastomotic leak was significantly higher in the LCA non-preservation group among all AR cases , as well as among AR cases with radical lymph node excision . Nevertheless , there was no difference in survival rate between LCA preservation group and non-preservation group , as measured by the Kaplan – Meier method . Conclusions Our data suggest that the preservation of the LCA in laparoscopic AR for middle and low rectal cancer is associated with lower anastomotic leak rates OBJECTIVE To investigate the effect of ligation level of inferior mesenteric artery ( IMA ) on postoperative defecation function in patients with rectal cancer . METHODS A total of 128 rectal cancer patients who were planned to undergo low anterior resection in the First Hospital of Zibo City between January 1 , 2012 and December 31 , 2013 were prospect ively enrolled and r and omly divided into IMA high ligation group(63 cases , cutting distance of 1.0 to 1.5 cm to the root of IMA ) and low ligation group(65 cases , cutting distance of 0.5 to 1.0 cm to the root of left colic artery originated from IMA ) . The efficacy , especially the defecation function , was observed and compared 3 months and 1 year after surgery between the two groups . RESULTS No significant difference was found in the number of harvested lymph nodes between two groups[8(1 - 30 ) vs. 7(2 - 28 ) , P=0.125 ] , but high ligation group had greater number of metastatic lymph nodes[1(0 - 9 ) vs. 0(0 - 8 ) , P=0.041 ] . Frequency of defecation in high ligation group was significantly higher than that in low ligation group during postoperative 3-month follow-up[5(2 - 10)/d vs. 3(1 - 8)/d , P=0.035 ] , whereas other indexes of defecation function were not significantly different(all P>0.05 ) . The proportion of patients needing laxatives in high ligation group was higher than that in low ligation group during postoperative 1-year follow-up [ 11.3%(6/53 ) vs. 1.7%(1/58 ) , P=0.038 ] , whereas other indexes of defecation function were not significantly different as well ( all P>0.05 ) . Three cases and 2 cases showed recurrence in high ligation group and low ligation group respectively during postoperative 1-year follow-up without significant difference(P=0.623 ) . CONCLUSION Low ligation of IMA in low anterior resection for rectal cancer is beneficial to the protection against defecation function Purpose Both “ high tie ” ( HT ) and “ low tie ” ( LT ) are well-known strategies in rectal surgery . The aim of this study was to compare colonic perfusion after HT to colonic perfusion after LT . Methods Patients undergoing rectal resection for malignancy were included . Colonic perfusion was measured with laser Doppler flowmetry , immediately after laparotomy on the antimesenterial side of the colon segment that was to become the afferent loop ( measurement A ) . This measurement was repeated after rectal resection ( measurement B ) . The blood flow ratios ( B/A ) were compared between the HT group and the LT group . Results Blood flow was measured in 33 patients , 16 undergoing HT and 17 undergoing LT .  Colonic blood flow slightly decreased in the HT group whereas the flow increased in the LT group . The blood flow ratio was significantly higher in the LT group ( 1.48 vs. 0.91 ; p = 0.04 ) , independent of the blood pressure . Conclusion This study shows the blood flow ratio to be higher in the LT group . This suggests that anastomoses may benefit from better perfusion when LT is performed Background Many Japanese surgeons routinely perform extended D3 lymph node dissection for the treatment of advanced rectosigmoid cancer with a view to achieving better tumor control . However , the application of a laparoscopic approach to perform D3 lymphadenectomy has been challenging . This phase 2 prospect i ve study aim ed to explore the oncologic results of this surgical approach . Methods The study was conducted during a 6-year period , in consideration of median follow-up time being > 3 years . The study subjects were tumor , node , metastasis system stage III rectosigmoid cancer staged by clinical images . The extent of D3 dissection and the postoperative lymph node mapping were according to the guidelines of the Japanese Society for Cancer of the Colon and Rectum . Patients were stratified according to the histopathologically proved highest level of involved lymph nodes and placed into N0 , N1 , N2 , and N3 groups . The primary end points of the study were the estimated time to recurrence and 5-year recurrence rate of cancer after laparoscopic D3 dissection . Results The estimated 5-year recurrence rate ( 20 % in the N0 group [ n = 10 ] ; 25 % in N1 [ n = 44 ] ; 33.3 % in N2 [ n = 30 ] ; and 42.8 % in N3 [ n = 14 ] ) , time to recurrence ( mean [ 95 % confidence interval ] 59.8 [ 42.6–76.9 ] months in the N0 group ; 56.8 [ 48.3–65.2 ] months in N1 ; 46.8 [ 37.5–56.1 ] months in N2 ; and 43.9 [ 28.3–59.4 ] months in N3 ) , and recurrence patterns were without significant difference ( all P values > .05 ) among N0 , N1 , N2 , and N3 groups . Therefore , by laparoscopic wide anatomic dissection , patients with lymph node involvement could be treated as well as those without lymph node metastasis . Laparoscopic D3 dissection facilitated the collection of more lymph nodes ( mean ± st and ard deviation , 27.4 ± 4.2 ) for histopathologic examination . Mapping of dissected lymph nodes showed that 18.2 % ( 16 of 88 ) patients had skip lymph node metastasis . D3 dissection  facilitated upstaging of cancer ( from N0 to N3 ) in five patients ( 5.1 % ) . However , this procedure result ed in transient voiding dysfunction in 77.5 % patients and loss of ejaculatory function in 91.7 % . By laparoscopic approach , the D3 lymph node dissection was safely performed through small wounds , result ing in quick functional recovery and only moderate blood loss ( 324.8 ± 44.5 mL ) , but at the expense of a long operation time ( 294.4 ± 34.8 minutes ) . Conclusions The good short-term oncologic results and quick convalescence mean that the laparoscopic D3 dissection may be recommended for patients with stage III rectosigmoid cancer who could accept the genitourinary dysfunction Background : The level of inferior mesenteric artery ( IMA ) ligation for anterior resection of rectal cancer has several considerations concerning oncological outcomes . The primary endpoint of this r and omized controlled trial ( RCT ) was to assess bowel function between high and low ligation . This study was intended to clarify oncological outcome as the secondary endpoint . Objective : The aim of this study was to assess in a prospect i ve RCT whether the ligation level of the IMA in rectal cancer influences oncological outcomes . Methods : Between February 2008 and December 2011 , 100 patients who underwent anterior resection for rectal cancer were r and omized to perform either high or low ligation of the IMA .  Oncological outcomes was the secondary endpoint of this RCT , whereas assessing bowel function was the primary endpoint . This RCT was registered at clinical trials.gov ( NCT00701012 ) . Results : There were no differences between the groups in terms of clinical data except for tumor stage . There were more advanced-stage patients in the high ligation group ( p = 0.046 ) . There were no lymph node ( LN ) metastases in the root of the IMA in the high ligation group . The average number of harvested LNs for the high and low ligation groups was 16.7 and 14.9 , respectively . There was no difference in disease-free survival ( DFS ) , site of first recurrence , and overall survival ( OS ) . When patients were in stage III , there was also no difference in DFS and OS . Conclusions : The ligation level of the IMA in rectal cancer may not influence oncological outcomes . However , further large-scale RCTs are needed to conclude this issue Aims The aim of this study is to evaluate the influence of dividing the inferior mesenteric artery ( IMA ) and preserving the left colic artery ( LCA ) on rectosigmoid cancer surgery . Patients and methods Colonic blood flow at the proximal site of the anastomosis was measured by laser Doppler flowmetry in 96 patients with cancer of the rectum and sigmoid colon while clamping IMA or LCA . Results were analyzed with patient characteristics and postoperative complications . Results Blood flow was significantly decreased by either IMA or LCA clamping , and its reduction rate was 38.5 ± 1.8 % , ranged from 0 to 82.8 % , or 16.4 ± 1.8 % , ranged from 0 to 66.2 % , respectively . For multivariate analyses , aging and male gender were predictive factors of high blood flow reduction by IMA clamping .  The reduction rate was significantly correlated with aging in male patients , while no such correlation was observed in women . Aging correlation in men was more significant in ultralow anterior resection cases . Three elderly male patients  received IMA high ligation among 19 patients who demonstrated more than 50 % blood flow reduction  by IMA clamping . Among these , two patients , those who underwent ultralow anterior resection , suffered severe anastomotic ischemia . Conclusions Colonic blood flow at the proximal site of the anastomosis was significantly decreased by either IMA or LCA clamping . Patients with high reduction by IMA clamping need intraoperative efforts to prevent anastomotic ischemia , particularly in elderly male patients who undergo ultralow anterior resection Background and Aims : Impaired blood perfusion may be implicated in anastomotic leakage after anterior resection for rectal cancer . We investigated whether high ligation of the inferior mesenteric artery or total mesorectal excision compromises visceral blood flow in the colonic limb and the rectal stump , respectively . Material and Methods : A prospect i ve cohort study was conducted in a university hospital setting . We used Laser Doppler flowmetry to evaluate the impact of level of tie on colonic limb perfusion and the extent of the mesorectal excision on the rectal blood flow . In the rectum , different quadrants were also assessed . The Mann – Whitney U test was used to compare mean blood flow ratios between groups . Results : Some 23 patients were recruited in a convenience sample during a period in 2012–2013 . The mean blood flow ratio was not decreased after high tie compared to low tie surgery ( 1.71 vs 1.19 ; p = 0.28 ) . Total mesorectal excision reduced the mean blood flow ratio in the rectum , as compared with partial mesorectal excision ( 0.76 vs 1.28 ; p = 0.14 ) . This was especially pronounced in the posterior aspect of the rectum ( 0.66 vs 1.68 ; p = 0.02 ) . Conclusion : High tie ligation did not seem to decrease colonic limb perfusion , while total mesorectal excision may decrease rectal blood flow . The posterior quadrant of the rectum might be particularly vulnerable to the dissection involved in total mesorectal excision 
    Output:
    
In term of sexual dysfunction , urinary retention , the number of apical lymph nodes , and long-term oncologic outcomes , there were no significant differences between the LCA non-preservation and LCA preservation group .
Conclusions : The pooled data provided evidence to support the LCA preservation preferred over LCA non-preservation in anastomotic leakage .