laparoscopic cholecystectomy with three or four ports is the standard operation for gallbladder diseases worldwide . the established use of 5 or 10  mm instruments and ports leads to small skin incisions in the upper abdominal wall . however , these scars are still visible and might be a potential risk factor for incisional hernia or adhesions . furthermore , new innovative methods such as notes ( natural orifice transluminal endoscopic surgery ) show promising first results regarding the technical feasibility and the possibility of scarless and painless operation [ 14 ] . at the present time , it becomes more important for younger patients to undergo surgery with none or at least very small scars . notes surgery might be the solution but is in case of transvaginal access to the abdominal cavity limited to female patients , and the procedure is not as easy to learn . in addition , this technique requires special instruments , which do not exist in a regular department of surgery . but due to the discussion about notes , another approach for the treatment of both genders is getting more attention from the public . the transumbilical access , described in the literature amongst others as laparoscopic single - site surgery ( less ) [ 5 , 6 ] . for this technique , a 15 to 20  mm incision is made direct through the umbilicus , which is defined as a natural embryonic scare , and , therefore , the procedure is also called e - notes ( embryonic natural orifice transumbilical endoscopic surgery ) . beside the positive cosmetic effect of transumbilical incision , less incisional this report describes our experience with single - incision cholecystectomies in 220 patients as standard procedure using a commercial available single - incision and conventional straight instruments . as far as we know , this is the largest series about single - incision surgery as standard procedure . between september 2008 and march 2010 , 220 laparoscopic single - incision cholecystectomies were performed at the  vivantes klinikum am urban  , berlin , germany by three experienced surgeons in standard technique . single - incision operation using two 5  mm and one 10  mm trocar was performed in 24 patients ( 11% ) between october 2008 and january 2009 . patients with symptomatic acute and chronic gallbladder disease were included in the observation , and all operations were performed consecutively . exclusion criteria for single - incision surgery were patients with gallbladder perforation , diagnosed in ultrasound or ct scan , with peritonitis or severe critical illness . all patients were hospitalized for at least two days and were completely informed about the single - incision technique . both arms are rolled out and the monitor is placed on the opposite site of the surgeons near the right shoulder . the operation begins with a longitudinal incision direct through the umbilicus between both umbilical edges ( approximately 1.5 to 2  cm ) . for a clear and safe closure of the linea alba at the end of the operation , the umbilicus has to be disconnected from the ground with a scissor . after good exposure of the linea alba with small hooks , the fascia has to cut with a scissor at a length of 15 to 20  mm . after dissolving of eventually existing adhesions with fingers , a langenbeck`s hook has to retract the inferior part of the incision and the single - port ( triport , olympus , germany ) can be safely brought into the abdominal cavity with the triport injector introducer . after establishing the pneumoperitoneum up to 14 mm hg with co , a 30 5 or 10  mm laparoscope was used for initial inspection of the abdominal cavity at a 1520 reverse trendelenburg , right - side - up position . we used as instruments conventional straight 5  mm graspers and a 5  mm hook electrocautery device . because of the gel valves , a continuous grease of the instruments ( instellagel , farco - pharma gmbh , germany ) is important for a safe , nonfitful handling . a special technique for a better movement inside the abdominal cavity is cross - handedness of the instruments . that means to undercross the instrument in the left hand under the instrument in the right hand . for a right hander the right hand holds the gallbladder with a grasper , and the hilum was prepared with a hook electrocautery device to expose the cystic duct and cystic artery . both structures were clipped with a 5  mm endoscopic clip applier ( ligamax m / l , ethicon endo - surgery , oh , usa ) and divided with scissors . after dissection the gallbladder from the fossa , the bladder was removed through the triport system without an endobag ( figure 1 ) . the fascial incision was closed with a nonabsorbable 0 suture ( prolene , ethicon , germany ) . finally , skin closure was done with an absorbable 4/0 suture ( monocryl , ethicon , germany ) . comparison of the umbilicus before ( figure 2(a ) ) transumbilical incision and at the end of the operation ( figure 2(b ) ) demonstrates that the incision is only at the ground of the umbilicus . the mean age of 142 females ( 65% ) and 78 males ( 35% ) was 47 years ( range : 1589 ) , and an elective surgery was planned for 154 patients ( 70% ) . the average american society of anesthesiologists ( asa ) classification was 2 ( range : 13 ) and the body mass index ( bmi ) 28 ( range : 1549 ) . mean hospital stay was 4 days ( range : 220 ) and 103 patients ( 47% ) had secondary diagnoses . thirty - seven patients ( 17% ) presented preoperative bile duct stones and of all received an endoscopic retrograde cholangiography ( erc ) . twenty - three patients ( 10% ) had clinical signs of biliary pancreatitis in medical history . preoperatively measured laboratory values were in a regular range for leucocytes , c - reactive protein ( crp ) , aspartate aminotransferase ( ast ) , alkaline phosphatase ( ap ) , and bilirubin . all patients received the same prophylactic antibiotic treatment of 2  g cefotaxim and 0.5  g metronidazol as single - shot dosage . mean operation time was 62 ( range : 26174 ) minutes , and 31 patients ( 14% ) had an incidential umbilical hernia . twenty - two patients ( 10% ) had previously undergone abdominal operation , and 54 patients ( 24% ) showed peritoneal adhesions . three patients ( 2% ) required conversion to a three - port technique because of a very large gallbladder with deep positioned hilus . an exact identification of the structures in the hilum via single port was not possible . one patient had a severe bleeding out of the cystic artery after the first clip was accidentally removed . a wound drainage was positioned at the end of operation in five cases ( 3% ) . one patient developed a 2  cm necrosis of the bile duct after mirizzi 's syndrome , two days after the initial operation . of 220 patients , 202 ( 92% ) had gallbladder stones and 150 patients ( 68% ) multiple stones . signs of gallbladder inflammation was diagnosed in 218 patients ( 99% ) , and 57 ( 26% ) patients had an acute cholecystitis . the classification of inflammation grade was in 74 patients ( 34% ) light , 101 patients ( 46% ) moderate and 45 patients ( 20% ) severe . a gallbladder hydrops was noted in 53 patients ( 24% ) , and ten patients ( 4.5% ) developed a shrunked gallbladder . we could demonstrate in one of the largest series that single - incision cholecystectomy is feasible and safe as standard technique for elective and acute gallbladder disease . most patients in our collective were satisfied with an almost scarless procedure and less pain after operation . previously published studies about multiport technique which included more than 1000 patients showed similar results compared to our study group [ 911 ] . the conversion rate to an open procedure was in former studies between 2% and 7% and in our population only 1% . major complications in multiport surgery such as bile duct or vessel injury were noted in 0.9% to 5.8% of all patients . although we had a comparative high complication rate of 5% , major complications like bile duct injury and necrosis happened only in two patients ( 1% ) , which is within the international standard . while single - incision surgery is getting more and more popular , patient numbers of previously published reports are still low [ 1219 ] . a review of eight studies from 2009 about single - incision cholecystectomy shows only two studies with 100 patients [ 14 , 17 ] , and the largest series of single - incision surgery , published by lee et al . one of the most important points in the discussion about notes or single - incision surgery is the extended operation time , because of a more complicated access to the abdominal cavity and the difficult handling of the instruments . the mean operation time in eight studies about less surgery including 365 patients was 80 minutes ( range : 5194 ) [ 1219 ] . but it is mentionable that studies with a higher case number like rivas et al . and one reason might be that the learning curve for this technique is certainly longer as for the three- or four - port technique . rivas et al . compared in their study including 100 patients the first 50 patients with the second 50 ones . age and bmi were almost equal , but the operation time was considerable reduced from 73 to 45 minutes . our mean operation time was 64 minutes , and it is still close to the regular time for conventional laparoscopic cholecystectomy . however , we had a high percentage of patients with acute cholecystitis compared to other studies with 5% and 9% [ 14 , 15 ] . a partition of our 220 cases into patients with acute and chronic cholecystitis showed a considerably different operation time . fifty - seven patients with acute cholecystitis required a mean operation time of 80 minutes ( range : 34174 ) and in contrast patients with chronic cholecystitis or no inflammation only 57 minutes ( range : 28159 ) . in addition , we could not indicate a reduction of operation time between the first 50% of operations and the second 50% like rivas et al . we performed the operation in the first 110 patients in a median time of 61 minutes and the second 110 patients in a median time of 65 minutes . it seems that the learning curve has an important impact but is for an experienced laparoscopic surgeon not as important in large series . but one reason for the more extended time in later operations might be the different view on the indication for single - port surgery after a major experience . the first 30 patients had not undergone previously abdominal surgery and , therefore , the operation easier to perform with a reduced operation time . another important point of criticism about single - incision surgery is the conversion rate to multiple ports . several studies reported about a conversion rate between 0% and 5% and are similar to our results with 2% [ 1316 , 18 , 19 ] . only one study of lee et al . had a high conversion rate of 13.5% because of technical difficulties . conversion rate to an open procedure was 1% in our study group and is described in the literature with 0% to 2% [ 1316 , 18 , 19 ] . we had to convert to an open procedure because of an acute bleeding from the cystic artery without an identifiable vessel in the hepatoduodenal ligament . a blind closure of the vessel with 5  mm clips or bipolar thermocoagulation could have injured structures in the ligament . the second patient had an unknown cholecystoduodenal fistula , which could not be closed in laparoscopic technique . considering these results , the conversion rate in single - incision surgery is even to multiport standard . a view on the complication rates after single - site surgery in the literature shows a percentage between 0% and 5,4% [ 1219 ] . four studies reported about no complications in their study population [ 13 , 14 , 18 , 19 ] . in our study , eight patients ( 5% ) developed postoperative complication , and six of these patients ( 3.5% ) had to undergo reoperation . except romanelli et al . , who had one case of postoperative hernia , other reports did not mention a reoperation . an analysis of our six patients showed that one of two patients with an incisional hernia had an incidential umbilical hernia and might have used a mesh for optimal wound closure . two patients developed a wound infection , and a wound debridement had to be performed in both cases . in one patient , the gallbladder was opened for extracting the stone and that might be the reason for infection . if the use of an endobag is more safely for preventing wound infection is questionable . we did not use one endobag in our series and had only an infection rate of 1% . these infections would have healed secondary , but because of a good cosmetic result , we decided to reoperate the patient . these hernias could be safely repaired within the standard closure of the fascia using a nonabsorbable suture . in conclusion , we could demonstrate for the first time that laparoscopic single - incision cholecystectomy as standard procedure is feasible and safe compared to conventional multiport technique . beside scarless operation , one major advantage in comparison to notes is the treatment option for both genders and the use of conventional instruments . results of long - term followup have to answer the theoretical increased risk of incisional hernia .
background and aims . 
 we describe our experience of performing transumbilical single - incision laparoendoscopic cholecystectomy as standard procedure for acute and chronic gallbladder diseases . methods . between september 2008 and march 2010 , 220 patients underwent laparoscopic single - incision surgery . a single port was used for 196 patients and two conventional 5  mm and one 10  mm port in 24 cases . 
 all operations were performed with straight instruments . 
 results . 
 single - incision surgery was successfully performed in 215 patients ( 98% ) . 
 three patients ( 1.4% ) required conversion to a three - port technique and two patients ( 0.9% ) to an open procedure . 
 average age of 142 women ( 65% ) and 78 men ( 35% ) was 47 years ( range : 1589 ) , average asa status 2 ( range : 13 ) and bmi 28 ( range : 1549 ) . 
 mean operative time was 62 minutes ( range : 26174 ) and 57 patients ( 26% ) had histopathological signs of acute cholecystitis . 
 eleven patients ( 5% ) developed to surgery - related complications and nine ( 4% ) of these required a reoperation . 
 the mean followup was 331.5 ( range : 11590 ) days . 
 conclusion . 
 transumbilical single - incision cholecystectomy is a feasible and safe new approach for routine cholecystectomy . after a short learning curve , operation time and complication rate are comparable with standard multiport operation . 
 in addition , most cases of acute cholecystitis can be performed with this technique .