during the past 2 decades , laparoscopic surgery has gained worldwide popularity resulting from its well - known characteristics of less postoperative pain , fewer complications , earlier discharge , and better cosmesis . smaller skin incisions in laparoscopic surgery were related to fewer unwanted side effects , including less postoperative pain . however , in recent studies comparing conventional and single - incision laparoscopic surgical procedures , the postoperative pain scores were not different . keyless abdominal rope - lifting surgery ( kars ) is a novel , gasless ( isobaric ) , single - incision laparoscopic surgical technique used in various gynecologic operations and cholecystectomies . besides being a single - incision laparoscopic technique , kars does not require carbon dioxide ( co2 ) use to inflate the abdominal wall and the intra - abdominal pressure is not elevated during the operation . in addition , postoperative shoulder pain seems to be more frequently observed after laparoscopic surgical procedures in which the intra - abdominal pressure is elevated to between 12 and 18 mm hg by use of co2 . in this study we aimed to compare the postoperative pain levels for kars and conventional multiport laparoscopy performed for adnexal cysts . although kars has been performed in our institute since the first half of 2010 , the study included benign ovarian cysts operated on between november 2011 and june 2013 . beginning in november 2011 , intraoperative and postoperative pain management for all operations performed in our unit was standardized ; thus the uniform management approach allowed us to collect and analyze the data from different surgical techniques . the study was approved by the local institutional ethical committee of kafkas university school of medicine . the included women had cystic masses including simple cysts with or without septation , endometriomas , and benign cystic teratomas . most of the participants complained of groin pain , menstrual bleeding disorders , dysmenorrhea , and infertility . emergency cases including patients with hemodynamic instability , severe abdominal pain , and inaccurate preoperative diagnoses were excluded . malignant cysts were excluded based on the patient 's history , clinical findings , ultrasonography and magnetic resonance imaging , and levels of cancer antigen 125 , alpha fetoprotein , carcinoembryonic antigen , and cancer antigen 199 . women who were diagnosed with an adnexal cyst and in whom a laparoscopic operation was indicated were invited to choose one of the operative techniques . because kars was performed only in our center , we could not design a randomized trial . thus the groups of this cross - sectional prospective clinical study were formed according to the women 's choice as the kars or conventional co2 laparoscopy groups . initial visual analog scale ( vas ) scores of 5.7  1.42 and 6.3  1.42 in patients undergoing kars and conventional laparoscopy , respectively , indicated that we needed at least 30 operations in each group to perform a study with a statistical power of 80% at an  level of .05 . the demographic and physical characteristics of the participating patients included their age , gravidity , parity , height , weight , and body mass index , as well as the number of abortions , ectopic pregnancies , and offspring . oral intake was prohibited starting at 11 pm , and a 135-ml solution containing 19 g of sodium dihydrogen phosphate and 7 g of disodium hydrogen phosphate was administered rectally at 6 am on the operation day . we used the operative laparoscopy study group 's classification system for staging intra - abdominal adhesions : 0 , none ; 1 , filmy and avascular ; 2 , dense and vascular ; and 3 , binding and cohesive . the abdominal access time in kars patients included the time needed for the construction of the pathway into the abdominal cavity and the placement of the lifting ropes . in conventional laparoscopy patients , the abdominal access time included the time needed for the creation of the co2 pneumoperitoneum at 14 mm hg of pressure and the insertion of the 3 intra - abdominal access ports . all included patients were considered class 1 or 2 according to the american society of anesthesiologists classification and received a standard anesthetic management regimen during the operations . we used propofol , 1.5 to 2.5 mg / kg , to induce anesthesia and facilitated intubation with rocuronium , 0.4 to 0.6 mg / kg . oxygen was supplemented before and after the intubation at rates of 100% and 50% ( mixed with the operating theater 's air ) , respectively . we used 2% sevoflurane and 50 g of fentanyl for anesthesia maintenance . to replace the fluid deficit , we used sodium chloride or ringer lactate solution at 10 ml / kg on intravenous insertion at 2 ml / kg per hour . unexpected bleeding was managed by use of additional crystalloid solution at 3 ml / kg per hour . atropine , 1 to 1.2 mg intravenously , was used to reverse the neuromuscular blockade . the postoperative pain management and vas pain score recordings were initiated in the obstetrics and gynecology service . all patients , regardless of initial vas pain score , received 50 mg of meperidine intramuscularly at the beginning of the postoperative period and 75 mg of diclofenac sodium during the second postoperative hour . vas pain scores were recorded at the beginning and second , fourth , and 24th hours of the postoperative period . beginning from the fourth postoperative hour , patients with vas pain scores of > 4 points received an additional dose of meperidine , 25 mg intramuscularly . kars has common features of conventional laparoscopy and laparotomy . during the creation of the abdominal access pathway , the umbilical fold is lifted with 2 clamps bilaterally and a third clamp at the center of the umbilicus . depending on the need for multiple instrument use or the depth and thickness of the subcutaneous tissue , the length of the incision may be adjusted smaller or larger . after the skin incision , the subcutaneous tissue is dissected bluntly with the tip of a fine instrument until the underlying fascia is reached . the opening is bluntly widened with the moderate stretching force of 2 fine retractors . at this stage , the surgeon can examine the intra - abdominal viscera by using his or her index or little finger to identify possible adhesions . the fascia at the entry site is lifted by 2 stitches placed at the lower and upper borders at the 6- and 12-o'clock positions ( figure 1 ) to guide the rest of the process . while the 2 stitches elevate the entry site , the intra - abdominal viscera is observed for possible injuries and adhesions by use of the introduced telescope . the lower and upper borders of the fascia underlying the umbilical incision are sutured at the 6- and 12-o'clock positions . the veress needle is unloaded from its cannula , and one tip of a no . the loaded cannula is introduced into the elevated entry site under direct or telescopic vision . the tip of the cannula is inserted toward the abdominal wall , 1 to 2 cm below the entry , under direct eye vision , and the tip is slid just above the peritoneum . it is turned to the right 6 to 7 cm to avoid injury to the epigastric vessels , and the abdominal wall is pierced from the inside toward the outside at approximately 5 cm below the umbilical entry . during this procedure , the tip of the veress cannula should always be maintained in an upward direction to avoid an accidental bowel injury . the tip of the suture is unloaded from the cannula outside the abdominal wall , and the unloaded cannula is withdrawn back from the entry . the other tip of the suture is loaded into the cannula , and the same steps are repeated . however , this time , the tip of the cannula is taken outside the abdominal cavity , 5 cm below the first tip then , an assistant elevates the abdominal wall , and the surgeon ties the sutures over the prepared sterile retractor located between the pubis and umbilicus ( figure 3 ) . the entry - site sutures are stretched during introduction of the telescope into the abdominal cavity to prevent staining of the optic of the telescope . the laparoscopic hand instruments are used through the same single incision ( figure 3 ) . there is no need to use trocars ( keyless ) to prevent gas leakage , and any surgical instrument ( a laparoscopic hand instrument or a conventional surgical hand instrument ) that can pass through the incision can be used . if the intra - abdominal operative space is not adequate to perform the operation , additional lifting sutures can be placed at the sites at which further elevations are required . lifting of a particular area ( eg , protrusion of the peritoneal folds or adipose tissue into the operative field , particularly in overweight patients ) can be managed by a suture just penetrating the skin and tied to the same retractor . if the operation is limited to the pelvis , the retractor used does not limit the surgeon 's motions . however , if an additional operation is anticipated at the upper side of the abdominal cavity , the placement of the retractor should be changed . the fascial layer is closed with continuous unlocked sutures while the lifting sutures assist the elevation of the fascial layer . 3 - 0 or 4 - 0 intracutaneous absorbable sutures and hidden into the umbilical fold . one month after the operation , the umbilical incision and the scars of the veress cannula are nearly indemonstrable ( figure 4 ) . the umbilical incision and the scars of the veress cannula are nearly indemonstrable 1 month after surgery . co2 laparoscopy is performed with the use of a 10-mm port ( infraumbilical port for the telescope ) and two 5-mm ports ( lateral ports for the hand instruments ) placed after the creation of co2 pneumoperitoneum using the veress needle . at the end of the surgical procedures , all fascial - layer incisions of the 10-mm ports are sutured before the placement of skin sutures ; however , only the skin incisions of 5-mm ports are closed with no . 3 - 0 or 4 statistical analysis was performed with spss software , version 16.0 ( spss , chicago , illinois ) . the distribution of variables was studied by use of kurtosis , skewness , and shapiro - wilk tests . normally distributed variables of the 2 groups were compared by use of the student t test , and non  normally distributed variables were compared by use of the mann - whitney u test . the  test was used to assess the probability of existence of shoulder pain in the 2 groups . a logistic regression model was created to study the confounding factors that influenced the perception of shoulder pain . the hosmer - lemeshow test showed that the model fit (  = 13 762 , p = .88 , n = 77 ) . kars has common features of conventional laparoscopy and laparotomy . during the creation of the abdominal access pathway , the umbilical fold is lifted with 2 clamps bilaterally and a third clamp at the center of the umbilicus . depending on the need for multiple instrument use or the depth and thickness of the subcutaneous tissue , the length of the incision may be adjusted smaller or larger . after the skin incision , the subcutaneous tissue is dissected bluntly with the tip of a fine instrument until the underlying fascia is reached . the opening is bluntly widened with the moderate stretching force of 2 fine retractors . at this stage , the surgeon can examine the intra - abdominal viscera by using his or her index or little finger to identify possible adhesions . the fascia at the entry site is lifted by 2 stitches placed at the lower and upper borders at the 6- and 12-o'clock positions ( figure 1 ) to guide the rest of the process . while the 2 stitches elevate the entry site , the intra - abdominal viscera is observed for possible injuries and adhesions by use of the introduced telescope . the lower and upper borders of the fascia underlying the umbilical incision are sutured at the 6- and 12-o'clock positions . the veress needle is unloaded from its cannula , and one tip of a no . the loaded cannula is introduced into the elevated entry site under direct or telescopic vision . the tip of the cannula is inserted toward the abdominal wall , 1 to 2 cm below the entry , under direct eye vision , and the tip is slid just above the peritoneum . it is turned to the right 6 to 7 cm to avoid injury to the epigastric vessels , and the abdominal wall is pierced from the inside toward the outside at approximately 5 cm below the umbilical entry . during this procedure , the tip of the veress cannula should always be maintained in an upward direction to avoid an accidental bowel injury . the tip of the suture is unloaded from the cannula outside the abdominal wall , and the unloaded cannula is withdrawn back from the entry . the other tip of the suture is loaded into the cannula , and the same steps are repeated . however , this time , the tip of the cannula is taken outside the abdominal cavity , 5 cm below the first tip . then , an assistant elevates the abdominal wall , and the surgeon ties the sutures over the prepared sterile retractor located between the pubis and umbilicus ( figure 3 ) . the entry - site sutures are stretched during introduction of the telescope into the abdominal cavity to prevent staining of the optic of the telescope . the laparoscopic hand instruments are used through the same single incision ( figure 3 ) . there is no need to use trocars ( keyless ) to prevent gas leakage , and any surgical instrument ( a laparoscopic hand instrument or a conventional surgical hand instrument ) that can pass through the incision can be used . if the intra - abdominal operative space is not adequate to perform the operation , additional lifting sutures can be placed at the sites at which further elevations are required . lifting of a particular area ( eg , protrusion of the peritoneal folds or adipose tissue into the operative field , particularly in overweight patients ) can be managed by a suture just penetrating the skin and tied to the same retractor . if the operation is limited to the pelvis , the retractor used does not limit the surgeon 's motions . however , if an additional operation is anticipated at the upper side of the abdominal cavity , the placement of the retractor should be changed . the fascial layer is closed with continuous unlocked sutures while the lifting sutures assist the elevation of the fascial layer . 3 - 0 or 4 - 0 intracutaneous absorbable sutures and hidden into the umbilical fold . one month after the operation , the umbilical incision and the scars of the veress cannula are nearly indemonstrable ( figure 4 ) . the umbilical incision and the scars of the veress cannula are nearly indemonstrable 1 month after surgery . kars has common features of conventional laparoscopy and laparotomy . during the creation of the abdominal access pathway , the umbilical fold is lifted with 2 clamps bilaterally and a third clamp at the center of the umbilicus . depending on the need for multiple instrument use or the depth and thickness of the subcutaneous tissue , the length of the incision may be adjusted smaller or larger . after the skin incision , the subcutaneous tissue is dissected bluntly with the tip of a fine instrument until the underlying fascia is reached . the opening is bluntly widened with the moderate stretching force of 2 fine retractors . at this stage , the surgeon can examine the intra - abdominal viscera by using his or her index or little finger to identify possible adhesions . the fascia at the entry site is lifted by 2 stitches placed at the lower and upper borders at the 6- and 12-o'clock positions ( figure 1 ) to guide the rest of the process . while the 2 stitches elevate the entry site , the intra - abdominal viscera is observed for possible injuries and adhesions by use of the introduced telescope . the lower and upper borders of the fascia underlying the umbilical incision are sutured at the 6- and 12-o'clock positions . the veress needle is unloaded from its cannula , and one tip of a no . the loaded cannula is introduced into the elevated entry site under direct or telescopic vision . the tip of the cannula is inserted toward the abdominal wall , 1 to 2 cm below the entry , under direct eye vision , and the tip is slid just above the peritoneum . it is turned to the right 6 to 7 cm to avoid injury to the epigastric vessels , and the abdominal wall is pierced from the inside toward the outside at approximately 5 cm below the umbilical entry . during this procedure , the tip of the veress cannula should always be maintained in an upward direction to avoid an accidental bowel injury . the tip of the suture is unloaded from the cannula outside the abdominal wall , and the unloaded cannula is withdrawn back from the entry . the other tip of the suture is loaded into the cannula , and the same steps are repeated . however , this time , the tip of the cannula is taken outside the abdominal cavity , 5 cm below the first tip . then , an assistant elevates the abdominal wall , and the surgeon ties the sutures over the prepared sterile retractor located between the pubis and umbilicus ( figure 3 ) . the entry - site sutures are stretched during introduction of the telescope into the abdominal cavity to prevent staining of the optic of the telescope . the laparoscopic hand instruments are used through the same single incision ( figure 3 ) . there is no need to use trocars ( keyless ) to prevent gas leakage , and any surgical instrument ( a laparoscopic hand instrument or a conventional surgical hand instrument ) that can pass through the incision can be used . if the intra - abdominal operative space is not adequate to perform the operation , additional lifting sutures can be placed at the sites at which further elevations are required . lifting of a particular area ( eg , protrusion of the peritoneal folds or adipose tissue into the operative field , particularly in overweight patients ) can be managed by a suture just penetrating the skin and tied to the same retractor . if the operation is limited to the pelvis , the retractor used does not limit the surgeon 's motions . however , if an additional operation is anticipated at the upper side of the abdominal cavity , the placement of the retractor should be changed . the fascial layer is closed with continuous unlocked sutures while the lifting sutures assist the elevation of the fascial layer . 3 - 0 or 4 - 0 intracutaneous absorbable sutures and hidden into the umbilical fold . one month after the operation , the umbilical incision and the scars of the veress cannula are nearly indemonstrable ( figure 4 ) . the umbilical incision and the scars of the veress cannula are nearly indemonstrable 1 month after surgery . co2 laparoscopy is performed with the use of a 10-mm port ( infraumbilical port for the telescope ) and two 5-mm ports ( lateral ports for the hand instruments ) placed after the creation of co2 pneumoperitoneum using the veress needle . at the end of the surgical procedures , all fascial - layer incisions of the 10-mm ports are sutured before the placement of skin sutures ; however , only the skin incisions of 5-mm ports are closed with no . 3 - 0 or 4 - 0 intracutaneous absorbable sutures . statistical analysis was performed with spss software , version 16.0 ( spss , chicago , illinois ) . the distribution of variables was studied by use of kurtosis , skewness , and shapiro - wilk tests . normally distributed variables of the 2 groups were compared by use of the student t test , and non  normally distributed variables were compared by use of the mann - whitney u test . the  test was used to assess the probability of existence of shoulder pain in the 2 groups . a logistic regression model was created to study the confounding factors that influenced the perception of shoulder pain . the hosmer - lemeshow test showed that the model fit (  = 13 762 , p = .88 , n = 77 ) . during a 20-month period , 77 women with benign ovarian cysts were operated on by kars ( n = 32 ) or conventional co2 laparoscopy ( n = 45 ) . the demographic data , physical characteristics , and preoperative findings of the participating women were summarized in table 1 . the demographic findings , surgical histories , and preoperative hematologic statuses of the groups did not differ significantly ( p > .05 ) . demographic data , physical characteristics , and preoperative findings of participating women in both groups data are presented as mean  standard deviation unless otherwise indicated . conventional multiport laparoscopy performed after creation of pneumoperitoneum . student t test ( used for normal distribution ) . mann - whitney test ( used for non - normal distribution ) . minor bleeding and unintended cyst ruptures were the only observed intraoperative complications . in none of the cases was a blood transfusion or postoperative intensive care admission needed . we did not need to convert to conventional laparoscopy or laparotomy in the kars group or to laparotomy or mini - laparotomy in the conventional laparoscopy group . simple oral analgesic use after the 24th hour of the postoperative period was adequate for postoperative pain relief in both groups . most of the intraoperative and postoperative findings were similar in the 2 groups ( p > .05 ) ; however , the abdominal cavity access and total operative times in the kars group were significantly longer than those in the conventional laparoscopy group ( p < .05 ) . intraoperative and postoperative findings according to operative technique data are presented as mean  standard deviation unless otherwise indicated . the vas pain scores at the beginning and second , fourth , and 24th hours of the postoperative period were significantly lower in the kars group ( p < .05 ) , although the differences in mean vas scores never exceeded 1 point . in addition , the women in the kars group needed less additional analgesia in comparison with those in the conventional laparoscopy group ( p < .05 ) . moreover , a higher number and percentage of the patients in the conventional co2 laparoscopy group had shoulder pain ( p < .05 ) . postoperative pain scores and additional analgesic requirements according to operative techniques data are presented as mean  standard deviation unless otherwise indicated . conventional multiport laparoscopy performed after creation of pneumoperitoneum . student t test ( used for normal distribution ) . mann - whitney test ( used for non - normal distribution ) . the  test analyzing shoulder pain showed that postoperative shoulder pain was significantly less frequent in the kars group (  = 5.304 , p = .021 , n = 77 ) . logistic regression for postoperative shoulder pain predicted that shoulder pain was affected only by the operation type and duration ( table 4 ) . although the operation duration was longer in the kars group , the frequency of shoulder pain was higher in the conventional laparoscopy group . the total operative time correlated positively with the abdominal access and rope - lifting process time , weight and body mass index of the women , adhesion score , cyst diameter , cyst rupture rate , length of hospital stay , and shoulder pain frequency ( p < .05 ) . in the conventional laparoscopy group , the total operative time correlated positively with the abdominal access time , weight and body mass index of the women , adhesion score , cyst diameter , cyst rupture rate , length of hospital stay , and shoulder pain frequency ( p < .05 ) . in comparison with conventional co2 laparoscopy , kars performed to treat benign ovarian cysts causes less postoperative abdominal and shoulder pain . , our study is the first comparing the postoperative pain scores and additional analgesic requirements of a gasless single - incision laparoscopic technique with conventional multiport co2 laparoscopy . postoperative pain scores during single - incision and conventional multiport co2 laparoscopic surgical procedures were compared previously ; however , the abdominal viscera was inflated by using co2 in all these studies . in our study all the operations for ovarian cysts were performed by the same surgical team under the same operating theater conditions . although the study included a control group , the participants determined which operative technique they would undergo ; thus the study lacks the power of randomization . the vas pain scores measured pain severity at the beginning and second , fourth , and 24th hours of the postoperative period ; however , the pain scores between the fourth and 24th hours were missing . postoperative shoulder pain was evaluated by its presence or absence ; however , its severity was not evaluated . pain sensation is subjective and may even differ for the same individual under different conditions . it develops motivations to avoid damaging conditions , to be cautious about the damaged tissue , and to prevent future conditions related to pain . from this point of view , we did not gather information about the past pain experiences of the patients . although the frequencies of previous operations were similar in both groups , we can not truly argue that the pain sensation , perception , and definition of the participants were similar . gynecologic operations including myomectomy , hysterectomy , ovarian cyst resection , colposuspension , and radical hysterectomy were performed by various surgeons . however , most of the published articles dealt with the feasibility , complications , operative times , and cosmesis of the procedures . in addition , although the previous surgical techniques consisted of gasless laparoscopic procedures , they had multiple abdominal entry sites . gargiulo and nezhat published an article describing the details of 3 new minimally invasive surgical approaches , including single - incision laparoscopic surgery . single - incision laparoscopic surgery seemed to yield more intraoperative complications because of the poor visualization and difficulty in maintaining pneumoperitoneum . gargiulo and nezhat concluded that the improved postoperative pain with single - incision laparoscopic surgical procedures was not proven in comparison with the conventional multiport co2 laparoscopies . similarly , murji et al conducted a meta - analysis of randomized controlled trials and high - quality observational studies with > 2000 patients and failed to ascertain the impact of single - incision laparoscopy surgery on postoperative pain because of the paucity of data and lack of uniform collection . however , both articles reviewed the results of studies including surgical procedures performed under elevated intra - abdominal pressure created by the insufflation of co2 . in our study in addition , postoperative shoulder pain experienced more frequently after co2 laparoscopies may increase the severity of perceived pain . thus the gasless ( isobaric ) nature of our technique may be an explanation for the contradiction with the findings of the previous publications . recently , gerbershagen et al studied postoperative pain scores on the first postoperative day in 70 764 german patients . surprisingly , they found that patients had reported high pain scores after many minor surgical procedures , and contrary to this finding , many major abdominal surgical procedures had caused comparatively less pain because of sufficient epidural analgesia . in our study we used a standardized pain management protocol in both groups ; thus our results suggest that the single - incision gasless laparoscopic technique yielded better pain scores than conventional co2 laparoscopy . in addition , at the 24th hour of the postoperative period , 59.3% of the women in the kars group and 35.5% of the women in the conventional multiport co2 laparoscopy group had vas pain scores of 0 points . moreover , none of the scores in either group were > 4 points . previous studies comparing the postoperative pain scores after single - incision and conventional laparoscopies mostly included cholecystectomies and showed similar pain scores for the same surgical procedures . in the prospective , randomized , multicenter trial conducted by marks et al , the postoperative pain scores did not differ between single - incision and multiport laparoscopies . however , a substantial increase in the incidence of hernia with cholecystectomies performed by single - incision laparoscopic surgery was found . in their study the closure techniques for the access sites were not briefly defined , and one of the centers unavoidably lost more than one third of its patients to follow - up . in addition , there were contradictory findings in other publications dealing with postoperative hernia formation after single - incision laparoscopies . moreover , all of the included operations had been performed after the creation of pneumoperitoneum by using co2 . better pain scores after kars may be the result of the avoidance of co2 pneumoperitoneum . although single - incision laparoscopic surgery was found to be feasible , safe , and reproducible in gynecology patients with benign and cancerous diseases , only a few articles suggested better postoperative pain scores , and some of them were case reports or pilot studies . in 2011 fagotti et al published their randomized controlled trial comparing postoperative pain after conventional laparoscopy and laparoendoscopic single - site surgery ( less ) for benign adnexal disease . they concluded that less was more advantageous than conventional multiport laparoscopy in terms of postoperative pain and the need for rescue analgesia . although we had similar postoperative findings in terms of pain , the need for rescue analgesics , and length of hospital stay , we also had different findings . the women included in the previous study had a higher median age ( 49 years in the less group and 42 years in the conventional laparoscopy group ) than the women in our study ( 33.5 years in the kars group and 38 years in the conventional laparoscopy group ) . the median body mass index , major cyst diameter , and previous abdominal operation rate and the mean operative time in both groups in our study were higher than the values in both groups in the previous study . whereas fagotti et al showed a lower bleeding rate in the less group , we observed similar bleeding rates in the kars and conventional multiport laparoscopy groups . in comparison with conventional multiport laparoscopy , fagotti et al showed significantly lower pain scores in the less group at the second and fourth postoperative hours ; however , we showed lower pain scores in the kars group initially postoperatively and at the second , fourth , and 24th hours of the postoperative period . in addition , we showed significantly less postoperative shoulder pain in the kars group , which may result from the gasless nature of kars . in 2011 prasad et al published their study comparing the postoperative pain scores after single - incision and conventional laparoscopic cholecystectomies . they observed similar pain scores in both groups and noticed that pain scores decreased after the operative times decreased in the single - incision group . although the decreased pain scores were also lower than the pain scores in the conventional laparoscopy group , the difference was not significant . in our study , although the kars group had significantly longer operative times ( by a mean of 16 minutes ) , the postoperative pain scores and additional analgesic requirements were significantly lower . our results suggest that kars yields better pain scores than conventional multiport co2 laparoscopy and that fewer additional analgesics are required after kars . however , one should note that our study included the results of surgical procedures performed for ovarian cysts . to increase the level of evidence , randomized prospective studies including various operations are needed . in addition , the gasless single - incision technique should be compared with single - incision laparoscopic surgical procedures using co2 to create pneumoperitoneum . in comparison with conventional co2 laparoscopy , kars performed to treat benign ovarian cysts causes less postoperative abdominal and shoulder pain . to our knowledge , our study is the first comparing the postoperative pain scores and additional analgesic requirements of a gasless single - incision laparoscopic technique with conventional multiport co2 laparoscopy . postoperative pain scores during single - incision and conventional multiport co2 laparoscopic surgical procedures were compared previously ; however , the abdominal viscera was inflated by using co2 in all these studies . in our study all the operations for ovarian cysts were performed by the same surgical team under the same operating theater conditions . although the study included a control group , the participants determined which operative technique they would undergo ; thus the study lacks the power of randomization . the vas pain scores measured pain severity at the beginning and second , fourth , and 24th hours of the postoperative period ; however , the pain scores between the fourth and 24th hours were missing . postoperative shoulder pain was evaluated by its presence or absence ; however , its severity was not evaluated . pain sensation is subjective and may even differ for the same individual under different conditions . it develops motivations to avoid damaging conditions , to be cautious about the damaged tissue , and to prevent future conditions related to pain . from this point of view , we did not gather information about the past pain experiences of the patients . although the frequencies of previous operations were similar in both groups , we can not truly argue that the pain sensation , perception , and definition of the participants were similar . gynecologic operations including myomectomy , hysterectomy , ovarian cyst resection , colposuspension , and radical hysterectomy were performed by various surgeons . however , most of the published articles dealt with the feasibility , complications , operative times , and cosmesis of the procedures . in addition , although the previous surgical techniques consisted of gasless laparoscopic procedures , they had multiple abdominal entry sites . gargiulo and nezhat published an article describing the details of 3 new minimally invasive surgical approaches , including single - incision laparoscopic surgery . single - incision laparoscopic surgery seemed to yield more intraoperative complications because of the poor visualization and difficulty in maintaining pneumoperitoneum . gargiulo and nezhat concluded that the improved postoperative pain with single - incision laparoscopic surgical procedures was not proven in comparison with the conventional multiport co2 laparoscopies . similarly , murji et al conducted a meta - analysis of randomized controlled trials and high - quality observational studies with > 2000 patients and failed to ascertain the impact of single - incision laparoscopy surgery on postoperative pain because of the paucity of data and lack of uniform collection . however , both articles reviewed the results of studies including surgical procedures performed under elevated intra - abdominal pressure created by the insufflation of co2 . in our study in addition , postoperative shoulder pain experienced more frequently after co2 laparoscopies may increase the severity of perceived pain . thus the gasless ( isobaric ) nature of our technique may be an explanation for the contradiction with the findings of the previous publications . recently , gerbershagen et al studied postoperative pain scores on the first postoperative day in 70 764 german patients . surprisingly , they found that patients had reported high pain scores after many minor surgical procedures , and contrary to this finding , many major abdominal surgical procedures had caused comparatively less pain because of sufficient epidural analgesia . in our study we used a standardized pain management protocol in both groups ; thus our results suggest that the single - incision gasless laparoscopic technique yielded better pain scores than conventional co2 laparoscopy . in addition , at the 24th hour of the postoperative period , 59.3% of the women in the kars group and 35.5% of the women in the conventional multiport co2 laparoscopy group had vas pain scores of 0 points . moreover , none of the scores in either group were > 4 points . previous studies comparing the postoperative pain scores after single - incision and conventional laparoscopies mostly included cholecystectomies and showed similar pain scores for the same surgical procedures . in the prospective , randomized , multicenter trial conducted by marks et al , the postoperative pain scores did not differ between single - incision and multiport laparoscopies . however , a substantial increase in the incidence of hernia with cholecystectomies performed by single - incision laparoscopic surgery was found . in their study the closure techniques for the access sites were not briefly defined , and one of the centers unavoidably lost more than one third of its patients to follow - up . in addition , there were contradictory findings in other publications dealing with postoperative hernia formation after single - incision laparoscopies . moreover , all of the included operations had been performed after the creation of pneumoperitoneum by using co2 . better pain scores after kars may be the result of the avoidance of co2 pneumoperitoneum . although single - incision laparoscopic surgery was found to be feasible , safe , and reproducible in gynecology patients with benign and cancerous diseases , only a few articles suggested better postoperative pain scores , and some of them were case reports or pilot studies . in 2011 fagotti et al published their randomized controlled trial comparing postoperative pain after conventional laparoscopy and laparoendoscopic single - site surgery ( less ) for benign adnexal disease . they concluded that less was more advantageous than conventional multiport laparoscopy in terms of postoperative pain and the need for rescue analgesia . although we had similar postoperative findings in terms of pain , the need for rescue analgesics , and length of hospital stay , we also had different findings . the women included in the previous study had a higher median age ( 49 years in the less group and 42 years in the conventional laparoscopy group ) than the women in our study ( 33.5 years in the kars group and 38 years in the conventional laparoscopy group ) . the median body mass index , major cyst diameter , and previous abdominal operation rate and the mean operative time in both groups in our study were higher than the values in both groups in the previous study . whereas fagotti et al showed a lower bleeding rate in the less group , we observed similar bleeding rates in the kars and conventional multiport laparoscopy groups . in comparison with conventional multiport laparoscopy , fagotti et al showed significantly lower pain scores in the less group at the second and fourth postoperative hours ; however , we showed lower pain scores in the kars group initially postoperatively and at the second , fourth , and 24th hours of the postoperative period . in addition , we showed significantly less postoperative shoulder pain in the kars group , which may result from the gasless nature of kars . in 2011 prasad et al published their study comparing the postoperative pain scores after single - incision and conventional laparoscopic cholecystectomies . they observed similar pain scores in both groups and noticed that pain scores decreased after the operative times decreased in the single - incision group . although the decreased pain scores were also lower than the pain scores in the conventional laparoscopy group , the difference was not significant . in our study , although the kars group had significantly longer operative times ( by a mean of 16 minutes ) , the postoperative pain scores and additional analgesic requirements were significantly lower . our results suggest that kars yields better pain scores than conventional multiport co2 laparoscopy and that fewer additional analgesics are required after kars . however , one should note that our study included the results of surgical procedures performed for ovarian cysts . to increase the level of evidence , randomized prospective studies including various operations are needed . in addition , the gasless single - incision technique should be compared with single - incision laparoscopic surgical procedures using co2 to create pneumoperitoneum . kars seems to cause less postoperative pain during the management of benign ovarian cysts in comparison with conventional multiport co2 laparoscopy .
background and objectives : keyless abdominal rope - lifting surgery is a novel , gasless , single - incision laparoscopic surgical technique . in this study we aimed to compare the postoperative pain from keyless abdominal rope - lifting surgery with carbon dioxide laparoscopy performed for benign ovarian cysts.methods:during a 20-month period , 77 women underwent surgery for a benign ovarian cyst . 
 keyless abdominal rope - lifting surgery and conventional carbon dioxide laparoscopy techniques were used for the operations in 32 women and 45 women , respectively . 
 the 2 operative techniques were compared with regard to demographic characteristics ; preoperative , intraoperative , and postoperative data including early postoperative pain scores ; and frequency of shoulder pain and analgesic requirements.results:data regarding demographic characteristics , preoperative findings , cyst diameters and rupture rates , intra - abdominal adhesions , intraoperative blood loss , and postoperative hospital stay did not differ between groups ( p > .05 ) . 
 however , the mean operative and abdominal access times were significantly longer in the keyless abdominal rope - lifting surgery group ( p < .05 ) . 
 visual analog scale pain scores at initially and at the second , fourth , and 24th hours of the postoperative period were significantly lower in the keyless abdominal rope - lifting surgery group ( p < .05 ) . 
 similarly , keyless abdominal rope - lifting surgery caused significantly less shoulder pain and additional analgesic use ( p < .05).conclusion : keyless abdominal rope - lifting surgery seems to cause less pain in the management of benign ovarian cysts in comparison with conventional carbon dioxide laparoscopy .