more recently , gervaz et al reported a 30% reduction in the duration of postoperative ileus and hospital stay when comparing laparoscopic versus open resection . single - incision laparoscopic surgery ( sils ) has developed over recent years and is gaining popularity in several surgical specialties including colorectal surgery . the theoretical benefits of sils include less pain , earlier discharge , and a better cosmetic result . however , technical challenges in sils include a lack of triangulation and limited space to manipulate the surgical instruments . well - designed studies comparing conventional multiport laparoscopic sigmoidectomy ( mls ) with sils sigmoidectomy ( silss ) are limited . in this single - institution study , we aimed to examine the safety , feasibility , and outcomes of silss for recurrent diverticulitis compared with a cohort undergoing mls in the same time period . the indications for surgery were established according to the guidelines of the american society of colon and rectal surgeons . surgery was performed a minimum of 6 weeks after the patient 's last episode of acute diverticulitis . after institutional review board approval , we retrospectively reviewed the charts of all patients who underwent a silss or mls procedure for recurrent diverticulitis performed between october 2011 and february 2013 at our institution . for each patient , the following variables were collected from our prospectively maintained database : age , gender , body mass index , previous abdominal surgery , number of episodes of acute diverticulitis , hinchy classification of the most severe episode , hinchy classification of the most recent episode , duration of operation , amount of blood loss , conversion to open surgery or addition of extra trocars , and postoperative data including morbidity , mortality , duration of epidural anesthesia , use of intravenous analgesics , and length of hospital stay . the clavien - dindo classification system , validated and tested for interobserver variation , was used to classify the severity and nature of complications . furthermore , overall satisfaction and evaluation of the cosmetic result were evaluated on a scale ranging from 0 ( very unhappy ) to 10 ( completely satisfied ) . these scores were previously used in a recent published randomized trial comparing open versus laparoscopic sigmoid resection for diverticulitis . finally , a cost analysis was performed comparing the total cost of the disposable surgical items ( linear staplers , energy devices , circular staplers , trocars or single - incision access platform ) in both groups . our protocol for general anesthesia consists of a balanced anesthesia using volatile anesthetics such as sevoflurane in association with a continuous infusion of remifentanil , a potent ultrashort - acting synthetic opioid analgesic . before patient induction after preoxygenation ( 6 l / min for 5 min through a face mask ) , anesthesia was induced using an intravenous bolus of propofol , a hypnotic agent , until the patient lost consciousness . a continuous infusion of remifentanil was started 2 minutes before induction at 0.25 g / kg / min based on the patient 's ideal body weight . after complete induction , a 0.5-mg / kg intravenous bolus of atracurium , a nondepolarizing neuromuscular blocker , was administered . two minutes after atracurium administration , the patient was intubated and top - up doses of atracurium were given every 20 minutes . the dose of remifentanil , initiated at 0.25 g / kg / min , was adjusted up or down according to the patient 's hemodynamic responses . oxygen saturation was maintained 95% and end - tidal carbon dioxide was maintained between 35 and 45 mm hg , with ventilatory settings left to the discretion of the anesthesiologist . after intubation , patients received 1 g of intravenous ( iv ) paracetamol and iv ibuprofen 75 mg if they were not contraindicated . patients were given standard iv prophylactic antibiotics to treat gram - negative and anaerobic bacteria . the patient was placed in the lithotomy position with moderate trendelenburg and right - sided tilt . the gelpoint access platform ( applied medical , rancho santa margarita , california ) was used in all cases . the inferior mesenteric artery and vein were transected with a 45-mm endogia white stapler ( covidien , endogia universal roticulator 452 - 0 , norwalk , connecticut ) . the mesorectum was dissected from the bowel at the level of the proximal rectum to prepare the distal margin of resection using the ligasure dolphin tip ( covidien , boulder , colorado ) . the high rectum was transected with a linear cutting roticulating stapler ( endogia , 60 mm purple cartridge , covidien ) . the sigmoid colon was recovered through the umbilical wound protector that is part of the applied gelpoint access platform . the sigmoid was resected and the anvil of a 28-mm circular stapler ( dst series pceea ; covidien ) was inserted in the descending colon and secured with a 20 prolene purse - string suture ( ethicon , norderstedt , germany ) . the bowel was returned to the peritoneal cavity and the pneumoperitoneum was re - established . the procedure was completed by joining the anvil to the circular stapler passed transanally , creating an end - to - end double - stapled anastomosis . once completed , the anastomosis was tested under a water bath for evidence of leakage . most of the steps in performing the mls are the same as those described for the silss . four ports were used ; a 5-mm port was placed just to the right of the umbilicus for the 30-degree 5-mm camera and 3 additional trocars were placed as follows : a 12-mm trocar just medial and superior to the anterior superior iliac spine , a 5-mm trocar in the left iliac fossa , and a 5-mm trocar in the right flank lateral to the epigastric vessels . a medial to lateral approach was used for submesocolic dissection as in the silss group . the mesorectum was dissected from the bowel at the level of the proximal rectum to prepare the distal margin of resection using the harmonic ace dissector ( ethicon endosurgery gmbh , norderstedt , germany ) . the same stapling devices were used in the silss group . for extracting the sigmoid colon , a 5-cm incision was made at the position of the left trocar in the left iliac fossa and a wound protector ( alexis wound retractor , small ; applied medical , rancho santa margarita , california ) was inserted . at the end of the procedure although we have not implemented an enhanced recovery after surgery program for colectomy at our institution , postoperative management of these patients includes avoidance of using nasogastric tubes , early dietary advancement , and early ambulation . for postoperative pain management , all patients received a patient - controlled analgesia device ( gemstartm infusion system , hispira , inc , lake forest , illinois ) . a loading dose was administered at the end of the surgical procedure ; pain therapy using iv paracetamol and iv ibuprofen had already been undertaken during anesthesia and was continued afterward . intravenous paracetamol 1 g was administered every 6 hours ; iv ibuprofen 75 mg was given only on demand . postoperative pain control was assessed using a 10-cm visual analog scale ( vas ) ( 0 = no pain , 10 = worst pain ) and recorded in the patient 's file by nurses . data were retrieved from routine prospective electronic and paper patient files . for all statistical analyses , analysis was performed using the fisher exact test ( discrete variables ) , the student t test or the wilcoxon rank - sum test ( continuous variables ) depending on normality ( or non - normality ) of variables . the mantel - haenszel  test was used as appropriate to test differences between the groups . the indications for surgery were established according to the guidelines of the american society of colon and rectal surgeons . surgery was performed a minimum of 6 weeks after the patient 's last episode of acute diverticulitis . after institutional review board approval , we retrospectively reviewed the charts of all patients who underwent a silss or mls procedure for recurrent diverticulitis performed between october 2011 and february 2013 at our institution . for each patient , the following variables were collected from our prospectively maintained database : age , gender , body mass index , previous abdominal surgery , number of episodes of acute diverticulitis , hinchy classification of the most severe episode , hinchy classification of the most recent episode , duration of operation , amount of blood loss , conversion to open surgery or addition of extra trocars , and postoperative data including morbidity , mortality , duration of epidural anesthesia , use of intravenous analgesics , and length of hospital stay . the clavien - dindo classification system , validated and tested for interobserver variation , was used to classify the severity and nature of complications . furthermore , overall satisfaction and evaluation of the cosmetic result were evaluated on a scale ranging from 0 ( very unhappy ) to 10 ( completely satisfied ) . these scores were previously used in a recent published randomized trial comparing open versus laparoscopic sigmoid resection for diverticulitis . finally , a cost analysis was performed comparing the total cost of the disposable surgical items ( linear staplers , energy devices , circular staplers , trocars or single - incision access platform ) in both groups . our protocol for general anesthesia consists of a balanced anesthesia using volatile anesthetics such as sevoflurane in association with a continuous infusion of remifentanil , a potent ultrashort - acting synthetic opioid analgesic . before patient induction after preoxygenation ( 6 l / min for 5 min through a face mask ) , anesthesia was induced using an intravenous bolus of propofol , a hypnotic agent , until the patient lost consciousness . a continuous infusion of remifentanil was started 2 minutes before induction at 0.25 g / kg / min based on the patient 's ideal body weight . after complete induction , a 0.5-mg / kg intravenous bolus of atracurium , a nondepolarizing neuromuscular blocker , was administered . two minutes after atracurium administration , the patient was intubated and top - up doses of atracurium were given every 20 minutes . the dose of remifentanil , initiated at 0.25 g / kg / min , was adjusted up or down according to the patient 's hemodynamic responses . oxygen saturation was maintained 95% and end - tidal carbon dioxide was maintained between 35 and 45 mm hg , with ventilatory settings left to the discretion of the anesthesiologist . after intubation , patients received 1 g of intravenous ( iv ) paracetamol and iv ibuprofen 75 mg if they were not contraindicated . patients were given standard iv prophylactic antibiotics to treat gram - negative and anaerobic bacteria . the patient was placed in the lithotomy position with moderate trendelenburg and right - sided tilt . the gelpoint access platform ( applied medical , rancho santa margarita , california ) was used in all cases . the inferior mesenteric artery and vein were transected with a 45-mm endogia white stapler ( covidien , endogia universal roticulator 452 - 0 , norwalk , connecticut ) . the mesorectum was dissected from the bowel at the level of the proximal rectum to prepare the distal margin of resection using the ligasure dolphin tip ( covidien , boulder , colorado ) . the high rectum was transected with a linear cutting roticulating stapler ( endogia , 60 mm purple cartridge , covidien ) . the sigmoid colon was recovered through the umbilical wound protector that is part of the applied gelpoint access platform . the sigmoid was resected and the anvil of a 28-mm circular stapler ( dst series pceea ; covidien ) was inserted in the descending colon and secured with a 20 prolene purse - string suture ( ethicon , norderstedt , germany ) . the bowel was returned to the peritoneal cavity and the pneumoperitoneum was re - established . the procedure was completed by joining the anvil to the circular stapler passed transanally , creating an end - to - end double - stapled anastomosis . once completed , the anastomosis was tested under a water bath for evidence of leakage . most of the steps in performing the mls are the same as those described for the silss . four ports were used ; a 5-mm port was placed just to the right of the umbilicus for the 30-degree 5-mm camera and 3 additional trocars were placed as follows : a 12-mm trocar just medial and superior to the anterior superior iliac spine , a 5-mm trocar in the left iliac fossa , and a 5-mm trocar in the right flank lateral to the epigastric vessels . a medial to lateral approach was used for submesocolic dissection as in the silss group . the mesorectum was dissected from the bowel at the level of the proximal rectum to prepare the distal margin of resection using the harmonic ace dissector ( ethicon endosurgery gmbh , norderstedt , germany ) . the same stapling devices were used in the silss group . for extracting the sigmoid colon , a 5-cm incision was made at the position of the left trocar in the left iliac fossa and a wound protector ( alexis wound retractor , small ; applied medical , rancho santa margarita , california ) was inserted . at the end of the procedure , although we have not implemented an enhanced recovery after surgery program for colectomy at our institution , postoperative management of these patients includes avoidance of using nasogastric tubes , early dietary advancement , and early ambulation . for postoperative pain management , all patients received a patient - controlled analgesia device ( gemstartm infusion system , hispira , inc , lake forest , illinois ) . a loading dose was administered at the end of the surgical procedure ; pain therapy using iv paracetamol and iv ibuprofen had already been undertaken during anesthesia and was continued afterward . intravenous paracetamol 1 g was administered every 6 hours ; iv ibuprofen 75 mg was given only on demand . postoperative pain control was assessed using a 10-cm visual analog scale ( vas ) ( 0 = no pain , 10 = worst pain ) and recorded in the patient 's file by nurses . data were retrieved from routine prospective electronic and paper patient files . for all statistical analyses , analysis was performed using the fisher exact test ( discrete variables ) , the student t test or the wilcoxon rank - sum test ( continuous variables ) depending on normality ( or non - normality ) of variables . the mantel - haenszel  test was used as appropriate to test differences between the groups . age , gender , american society of anesthesiologists ( asa ) score , and body mass index were comparable between the 2 groups . furthermore , the percentage of patients who had undergone previous abdominal surgery , the number of episodes of acute diverticulitis , the severity of attacks , and the severity of the most recent attack of diverticulitis were also comparable between the 2 groups . clinicopathologic characteristics of patients undergoing sigmoidectomy for diverticulitis surgical outcomes of silss versus mls are shown in table 2 . the mean operative time for silss was 13 minutes longer than it was for mls ( p = .0012 ) . estimated blood loss was similar and minimal in both groups . in a larger proportion of patients in the silss group , 2 linear staplers were needed for transection at the rectum compared with the mls group ( 11/20 [ 55% ] vs 7/40 [ 17.5% ] ) . however there was one conversion to open surgery in the mls group . in 2 patients in the mls group , the rate of postoperative complications was not significantly different between the 2 groups . in all , 22 ( 36.7% ) patients had a clavien - grade complication ; all complications were clavien grade i or ii . this patient had a 25-mm large intraabdominal abscess along with a small anastomotic defect at the stapler line , which was confirmed by a computed tomography scan . the patient was readmitted because of fever 10 days after surgery and was treated conservatively with iv antibiotics ( meropenem 3  2 g / d for 1 week ) . postoperative recovery with respect to return to bowel function or return to oral intake was faster in the silss group than in the mls group ( p = .0446 and p = .0137 , respectively ) . although duration of epidural anesthesia was equal in both groups and there was no difference in nonsteroidal antiinflammatory drug ( nsaid ) use , a significant reduction in pain was noted on days 1 and 2 postoperatively when comparing vas scores . length of hospital stay was shorter in the silss group but not statistically significant ( p = .0536 ) . there were 3 readmissions : one from the silss group because of gastroparesis with nausea and vomiting and two in the mls because of , respectively , pneumonia and a pelvic abscess at the stapler line that was considered a small clinical anastomotic leakage . results for overall satisfaction reached borderline statistical significance and hospital stay was also borderline statistically shorter when compared with mls ( table 4 ) . the average total cost of the disposable surgical items was higher in the silss group (  2599 ) than in the mls group (  2320 ) ( p < .0001 ) . age , gender , american society of anesthesiologists ( asa ) score , and body mass index were comparable between the 2 groups . furthermore , the percentage of patients who had undergone previous abdominal surgery , the number of episodes of acute diverticulitis , the severity of attacks , and the severity of the most recent attack of diverticulitis were also comparable between the 2 groups . the mean operative time for silss was 13 minutes longer than it was for mls ( p = .0012 ) . estimated blood loss was similar and minimal in both groups . in a larger proportion of patients in the silss group , 2 linear staplers were needed for transection at the rectum compared with the mls group ( 11/20 [ 55% ] vs 7/40 [ 17.5% ] ) . however , this did not result in a higher anastomotic leak rate . there was one conversion to open surgery in the mls group . in 2 patients in the mls group , the rate of postoperative complications was not significantly different between the 2 groups . in all , 22 ( 36.7% ) patients had a clavien - grade complication ; all complications were clavien grade i or ii . this patient had a 25-mm large intraabdominal abscess along with a small anastomotic defect at the stapler line , which was confirmed by a computed tomography scan . the patient was readmitted because of fever 10 days after surgery and was treated conservatively with iv antibiotics ( meropenem 3  2 g / d for 1 week ) . postoperative recovery with respect to return to bowel function or return to oral intake was faster in the silss group than in the mls group ( p = .0446 and p = .0137 , respectively ) . although duration of epidural anesthesia was equal in both groups and there was no difference in nonsteroidal antiinflammatory drug ( nsaid ) use , a significant reduction in pain was noted on days 1 and 2 postoperatively when comparing vas scores . length of hospital stay was shorter in the silss group but not statistically significant ( p = .0536 ) . there were 3 readmissions : one from the silss group because of gastroparesis with nausea and vomiting and two in the mls because of , respectively , pneumonia and a pelvic abscess at the stapler line that was considered a small clinical anastomotic leakage . the cosmetic result was better in the silss group . results for overall satisfaction reached borderline statistical significance and hospital stay was also borderline statistically shorter when compared with mls ( table 4 ) . the average total cost of the disposable surgical items was higher in the silss group (  2599 ) than in the mls group (  2320 ) ( p < .0001 ) . as is shown in table 5 , several case series of sils colectomy have been published recently . however , few comparative studies have been published comparing single - incision laparoscopic colectomy with standard laparoscopic multiport colectomy . as stated in a recent systematic review , there is significant heterogeneity in study group characteristics , indications for surgery and operative techniques . most reports are case series that include benign ( ie , diverticulitis , endometriosis , colitis , polyps not amendable to colonoscopic polypectomy ) and malignant conditions and include different types of resections ( ie , right , transverse , total and left colectomies ) . in our comparative study all patients underwent the same type of colonic resection by the same surgeon , which reduces the heterogeneity of this study . questions remain about the safety of sils for colorectal cancer resection and there are no data on its long - term outcomes ( disease - free or disease - specific survival ) . overview of published sils colectomy series including > 20 patients most published series are either not comparative or include different types of resections or different types of colonic disease , creating significant heterogeneity . the silss and mls groups were comparable for age , gender and asa distribution and body mass index . there was no significant difference between the 2 groups in terms of history of previous abdominal surgery , number and severity of episodes of diverticulitis and severity of the last episode of diverticulitis . these factors could potentially influence the operative difficulty and subsequently the complication rate and further outcome . several aspects of silss differ from the mls procedure , including the camera view , crossing hands during dissection , and lack of triangulation . operative time was 104 minutes for the silss procedure , which is only 13.1 minutes longer than the 90.9 minutes required for the mls . a recently published german single - center experience with sils colectomy reported a conversion rate to open surgery of 6.3% , half of which were in patients undergoing sigmoid colectomy with a high anterior resection or left hemicolectomy , 95% of whom had diverticulitis . in the current series , no cases were converted to open surgery and no additional ports were placed in the silss group . one case in the mls group had to be converted to open surgery because of extensive adhesions . this 52-year - old female patient had a previous history of extensive surgery for endometriosis including hysterectomy and ovariectomy . the proportion of cases requiring 2 linear staplers to achieve full transection of the proximal rectum was higher in the silss group . this indicates a higher risk of oblique stapling in the sils procedures . in the silss group , the linear stapler device was placed through the single - port device in the umbilicus , creating a difficult angle for complete tranverse rectal stapling because the axis of the stapler is in parallel with the axis of the rectum . therefore an additional stapler was needed in more than half of single - port procedures . in the mls group , the stapler was placed through the 12-mm port in the left lower quadrant , facilitating transverse stapling of the proximal rectum . in another recent case - matched study , the same findings were published regarding the number of staplers . however , in their series the leakage rate was higher in the silss group . we did not find a higher leakage rate in the silss group compared with the mls group or in the subset of cases in which 2 staplers were used . in patients requiring 2 linear staplers , the area where the 2 stapler lines crossed was used for the circular stapled anastomosis . in this study , the clavien - dindo classification system , validated and tested for interobserver variation , was used to classify the severity and nature of complications . the overall complication rate was 36.7% ( 35% in the silss group and 37.5% in the mls group , p = 1.000 ) . not only the frequency but also the severity of complications was the same when the clavien - dindo classification was used to compare both groups . the patient was readmitted because of fever and was treated conservatively with iv antibiotics , so this was graded as a clavien ii complication . there have been 2 randomized controlled trials comparing sils with laparoscopic cholecystectomy , and both showed better pain profiles in the sils group . of all nonrandomized case - comparison studies comparing sils and multiport or hand - assisted laparoscopic colonic resections , only 3 studies assessed postoperative pain . papaconstaniou et al found a significant reduction in postoperative pain in patients undergoing sils colonic resection when looking at vas scores on postoperative days 1 and 2 . by postoperative day 3 , their series included different resections and multiport and hand - assisted laparoscopic resections , which makes it a heterogeneous patient population . in our standardized population containing only silss and mls , we found identical results . furthermore , there was no statistical difference in the length of epidural analgesic use in our series nor need for nsaid usage between both groups . in contrast to these results , lu et al reported that patients in the sils group experienced more pain on postoperative day 1 , and wolthuis et al found no difference in pain levels . . currently , health care providers and health care systems are under extreme pressure to provide treatment modalities that are cost effective without compromising patient care . therefore a cost analysis of the sils approach compared with the traditional mls approach was performed to compare total cost of the disposables . total cost for disposables was higher in the silss group (  2599 ) than in the mls group (  2320 ) ( p < .0001 ) . however , the cost of the shorter hospital stay should be taken into consideration because hospital stay was also borderline statistically shorter when compared with mls . first , although we matched the 2 groups for different variables and although the patient characteristics in the 2 groups were comparable , this was not a randomized study and thus may have been prone to certain bias . second , we do acknowledge interobserver variability and bias affecting the results , because the patients were reviewed in the clinic by the surgeon who performed the surgical procedure . furthermore , several findings may be the result of a type 1 error because there are only 20 patients included in the silss group . finally , a better comparison group would probably have been an mls group with a comparable size extraction site at the midline as opposed to a muscle - splitting incision . our results show that silss for diverticulitis is safe and can be performed without increasing morbidity . it is associated with significantly better short - term benefits including earlier recovery of bowel function and a significant reduction in postoperative pain and better cosmesis . results for overall satisfaction reached borderline statistical significance , and hospital stay was also borderline statistically shorter when compared with mls .
background and objectives : in this single - institution study , we aimed to compare the safety , feasibility , and outcomes of single - incision laparoscopic sigmoidectomy ( silss ) with multiport laparoscopic sigmoidectomy ( mls ) for recurrent diverticulitis.methods:between october 2011 and february 2013 , 60 sigmoidectomies were performed by the same surgeon . 
 forty patients had a mls and 20 patients had a silss . 
 outcomes were compared.results:patient characteristics were similar . 
 there was no difference in morbidity , mortality or readmission rates . 
 the mean operative time was longer in the silss group ( p = .0012 ) . in a larger proportion of patients from the silss group , 
 2 linear staplers were needed for transection at the rectum ( p = .006 ) . 
 the total cost of disposable items was higher in the silss group ( p < .0001 ) . 
 no additional ports were placed in the silss group . 
 return to bowel function or return to oral intake was faster in the silss group ( p = .0446 and p = .0137 , respectively ) . 
 maximum pain scores on postoperative days 1 and 2 were significantly less for the silss group ( p = .0014 and p = .047 , respectively ) . 
 hospital stay was borderline statistically shorter in the silss group ( p = .0053 ) . 
 silss was also associated with better cosmesis ( p < .0011).conclusion : silss is feasible and safe and is associated with earlier recovery of bowel function , a significant reduction in postoperative pain , and better cosmesis .