document: to date , laparoscopic transabdominal preperitoneal ( tapp ) mesh repair has been regarded as one of the standard treatments for inguinal hernia in adults . 
   however , patients who undergo the procedure experience a significantly higher incidence of early postoperative pain , which is associated with subsequent chronic pain . surgical trauma to the abdominal wall , mesh implantation , and mesh fixation in the groin region have been indicated as possible causes of the pain . 
   the ideal mesh material is still being debated , but mesh fixation with fibrin glue or the alternate choice of self - fixating mesh with microhooks has obvious advantages in reducing chronic groin pain . in the context of surgical tissue trauma at trocar sites , 
   guidelines suggest that the use of a 10-mm trocar in the umbilical region or in the oblique abdominal wall predisposes patients to local nerve or vessel injury and port - site hernia . 
   thus , an improvement in current laparoscopic hernia surgery has been the further reduction of the size of the abdominal wall incision for trocar insertion . 
   modified tapp repairs by needlescopic surgery ( ntapp ) , with the use of smaller trocars than the standard 10-mm optical trocars and 5-mm working trocars , have been shown to be superior in patient outcomes over conventional tapp repairs . 
   also tapp repairs in single - incision laparoscopic surgery ( stapp ) , with a reduction in the number of ports to only 1 umbilical port , have been put forward with good initial results . however , a direct comparison between these 2 advanced minimally invasive approaches is still missing . 
   the purpose of this study was to compare the perioperative extent of surgical trauma and its postoperative impact on the abdominal wall after ntapp and stapp repair . 
   for this retrospective cohort study with institutional review board approval , 85 patients with a single - sided primary inguinal hernia were recruited at a community hospital between november 1 , 2009 , and july 31 , 2012 . in this period of 32 months 
   demographic and surgical data , including gender , age , body mass index , location and size of the inguinal hernia , length of the umbilical skin incision for the trocar port , operative time , and length of hospital stay were retrospectively retrieved from surgical records . 
   on postoperative day 3 , all patients were scheduled for a wound check and removal of skin staples . in october 2013 , 
   the patients were asked to complete a questionnaire and undergo a physical examination in the outpatient clinic . 
   the following information was then recorded : hernia recurrence ; postoperative pain , according to the visual analog scale ( vas ) ( 0 = no pain ; 10 = worst pain ) ; postoperative mobility of the abdominal wall , determined by janda 's test , a sit - up exercise ( 0 = no recovery of normal muscle power ; 5 = full recovery of normal muscle power ) ; postoperative cosmetic satisfaction , according to the cosmetic vas ( 0 = completely dissatisfied ; 10 = completely satisfied ) ; and period of sick leave after hospital discharge for employed workers . 
   the operative procedure in laparoscopic tapp mesh repair was described in depth in our previous study . in brief 
   , it involved establishing pneumoperitoneum , dissecting the peritoneal flap and the preperitoneal space with an electric hook , placing a 15  9-cm parietene progrip self - fixating monofilament polypropylene mesh ( covidien , dublin , ireland ) , and closing the peritoneal flap with a v - loc barbed suture ( covidien ) . in the ntapp group , 
   the length of the transverse skin incision at the umbilicus was first measured , and an 8-mm trocar was inserted for the use of a 5-mm optical instrument . under optical view , a 5-mm trocar for the electric hook on the right side of the abdomen and a 2-mm trocar for the grasping forceps on the left side of the abdomen were placed at the level of the umbilicus on the midclavicular line . in the stapp group , 
   the umbilical skin incision length was also first measured , and a gelpoint advanced - access platform ( applied medical , rancho santa margarita , california ) was placed through the umbilicus . 
   a 5-mm optical trocar and two 5-mm working trocars were then positioned in this single - port - access device . 
   the self - fixating parietene progrip mesh , with microhooks on its underside , was folded in a special manner , as demonstrated in our previous publication . 
   it was then inserted into the abdominal cavity through the 8-mm umbilical trocar in the ntapp group or through the 510-mm compatible cannula of the gelpoint advanced - access platform in the stapp group . 
   once hernia repair was completed , the umbilical wound was closed with an absorbable fascia suture and skin staples in all ntapp and stapp procedures . 
   the lateral 5- and 2-mm trocar wounds in the ntapp group were closed with steri - strips adhesive skin closures ( 3 m health center , st . 
   all operations were performed on an elective basis in patients under general anesthesia by the same experienced surgeon . 
   spss 22 for windows ( ibm corp . , somers , new york ) was used for statistical analysis . 
   data are expressed as percentages for categorical variables and as the mean  sd for continuous variables . 
   comparisons between the 2 operative approaches were performed with the  test and student 's t test , as applicable . 
   for this retrospective cohort study with institutional review board approval , 85 patients with a single - sided primary inguinal hernia were recruited at a community hospital between november 1 , 2009 , and july 31 , 2012 . in this period of 32 months 
   demographic and surgical data , including gender , age , body mass index , location and size of the inguinal hernia , length of the umbilical skin incision for the trocar port , operative time , and length of hospital stay were retrospectively retrieved from surgical records . 
   on postoperative day 3 , all patients were scheduled for a wound check and removal of skin staples . in october 2013 , 
   the patients were asked to complete a questionnaire and undergo a physical examination in the outpatient clinic . 
   the following information was then recorded : hernia recurrence ; postoperative pain , according to the visual analog scale ( vas ) ( 0 = no pain ; 10 = worst pain ) ; postoperative mobility of the abdominal wall , determined by janda 's test , a sit - up exercise ( 0 = no recovery of normal muscle power ; 5 = full recovery of normal muscle power ) ; postoperative cosmetic satisfaction , according to the cosmetic vas ( 0 = completely dissatisfied ; 10 = completely satisfied ) ; and period of sick leave after hospital discharge for employed workers . 
   the operative procedure in laparoscopic tapp mesh repair was described in depth in our previous study . in brief 
   , it involved establishing pneumoperitoneum , dissecting the peritoneal flap and the preperitoneal space with an electric hook , placing a 15  9-cm parietene progrip self - fixating monofilament polypropylene mesh ( covidien , dublin , ireland ) , and closing the peritoneal flap with a v - loc barbed suture ( covidien ) . in the ntapp group , 
   the length of the transverse skin incision at the umbilicus was first measured , and an 8-mm trocar was inserted for the use of a 5-mm optical instrument . under optical view , a 5-mm trocar for the electric hook on the right side of the abdomen and a 2-mm trocar for the grasping forceps on the left side of the abdomen were placed at the level of the umbilicus on the midclavicular line . in the stapp group , 
   the umbilical skin incision length was also first measured , and a gelpoint advanced - access platform ( applied medical , rancho santa margarita , california ) was placed through the umbilicus . 
   a 5-mm optical trocar and two 5-mm working trocars were then positioned in this single - port - access device . 
   the self - fixating parietene progrip mesh , with microhooks on its underside , was folded in a special manner , as demonstrated in our previous publication . 
   it was then inserted into the abdominal cavity through the 8-mm umbilical trocar in the ntapp group or through the 510-mm compatible cannula of the gelpoint advanced - access platform in the stapp group . once hernia repair was completed , the umbilical wound was closed with an absorbable fascia suture and skin staples in all ntapp and stapp procedures . 
   the lateral 5- and 2-mm trocar wounds in the ntapp group were closed with steri - strips adhesive skin closures ( 3 m health center , st . 
   all operations were performed on an elective basis in patients under general anesthesia by the same experienced surgeon . 
   spss 22 for windows ( ibm corp . , somers , new york ) was used for statistical analysis . 
   data are expressed as percentages for categorical variables and as the mean  sd for continuous variables . 
   comparisons between the 2 operative approaches were performed with the  test and student 's t test , as applicable . 
   patient characteristics in the ntapp and stapp groups were comparable at baseline ( male : female 5.4:1 vs 5.3:1 ; age 52.5 y vs 48.3 y ; bmi 25.3 kg / m vs 24.4 kg / m ; direct : indirect : pantaloon hernia , 32:58:10% vs 31.4:54.3:14.3% ; and hernia diameter , 2.4 cm vs 2.3 cm ) . 
   only 2 patients in the stapp group required an additional 5-mm trocar port in the lateral abdomen , to create a better view of the operative field . 
   the mean measured umbilical skin incision length was 13  4 mm in the ntapp group , compared with 27  3 mm in the stapp group ( p < .001 ) . 
   the ntapp procedure required significantly less operating time than the stapp procedure ( ntapp 54.8  16.9 minutes vs stapp 85.9  19.7 minutes ; p < .001 ) . 
   the reduction in operative time was particularly seen in cases of direct hernia ( figure 1 ) . 
   the mean length of postoperative hospital stay was 1.8  0.7 days for the ntapp group and 2.0  0.9 d for the stapp group ( p = .21 ) . by the time of the wound check on postoperative day 3 
   , one patient in the stapp group had a superficial hematoma in the umbilical region that required only conservative treatment . 
   operative time of ntapp and stapp hernia repair . the mean operative time for a direct or an indirect hernia was significantly shorter in ntapp repair ( direct : ntapp 
   .001 ; indirect : ntapp 59.4 minutes vs stapp 88.7 minutes ; p < .001 ) . after a mean follow - up time of 33.5 months for the ntapp group and 30.1 months for the stapp group , 
   40 ntapp patients ( 80% ) and 26 stapp patients ( 74% ) were re - examined in the outpatient clinic . 
   neither inguinal nor port - site hernia occurred in either group . regarding immediate postoperative pain , there was a tendency for longer pain duration in the wound region after the stapp procedure ( ntapp , 5.6  5.5 days vs stapp 9.8  8.4 days ; p = .072 ) . 
   also stapp patients experienced greater wound pain intensity when they began to resume their regular daily activities after hospital discharge ( ntapp 2.7  2.1 vas vs stapp 4.4  1.9 vas ; p = .016 ) . 
   one patient in the ntapp group had chronic discomfort , with paresthesia in the groin region . 
   one patient in the stapp group developed postherniorrhaphy pain syndrome and remained on paid sick leave at home for approximately 2 months . at the time of the follow - up examination , both groups achieved similar results in janda 's clinical test for abdominal wall mobility ( ntapp 4.7  0.5 vs stapp 4.1  1.1 ; p = .101 ) . 
   however , 7 ( 20% ) patients who underwent stapp repair noted a subjective deterioration in abdominal wall mobility in the questionnaire , whereas no patients who underwent ntapp repair had such an experience . 
   cosmetic satisfaction was equally high , with a vas score of 9.7  0.6 in the ntapp group and 9.6  0.7 in the stapp group ( p = .836 ) . 
   sick leave records showed that the ntapp group had a significantly shorter mean period of sick leave , compared with the stapp group ( ntapp 11.2  8.4 days vs stapp 24.1  20.1 days ; p = .02 ) . 
   notably , even with cessation of postoperative wound pain , 27 ntapp patients ( 54% ) and 32 ( stapp patients 91.4% ) remained on sick leave at the follow - up assessment ( p = .045 ) . 
   patient characteristics in the ntapp and stapp groups were comparable at baseline ( male : female 5.4:1 vs 5.3:1 ; age 52.5 y vs 48.3 y ; bmi 25.3 kg / m vs 24.4 kg / m ; direct : indirect : pantaloon hernia , 32:58:10% vs 31.4:54.3:14.3% ; and hernia diameter , 2.4 cm vs 2.3 cm ) . 
   only 2 patients in the stapp group required an additional 5-mm trocar port in the lateral abdomen , to create a better view of the operative field . 
   the mean measured umbilical skin incision length was 13  4 mm in the ntapp group , compared with 27  3 mm in the stapp group ( p < .001 ) . 
   the ntapp procedure required significantly less operating time than the stapp procedure ( ntapp 54.8  16.9 minutes vs stapp 85.9  19.7 minutes ; p < .001 ) . 
   the reduction in operative time was particularly seen in cases of direct hernia ( figure 1 ) . 
   the mean length of postoperative hospital stay was 1.8  0.7 days for the ntapp group and 2.0  0.9 d for the stapp group ( p = .21 ) . by the time of the wound check on postoperative day 3 
   , one patient in the stapp group had a superficial hematoma in the umbilical region that required only conservative treatment . 
   operative time of ntapp and stapp hernia repair . the mean operative time for a direct or an indirect hernia was significantly shorter in ntapp repair ( direct : ntapp 
   47.1 minutes vs stapp 82.5 minutes ; p < .001 ; indirect : ntapp 59.4 minutes vs stapp 88.7 minutes ; p < .001 ) . 
   after a mean follow - up time of 33.5 months for the ntapp group and 30.1 months for the stapp group , 40 ntapp patients ( 80% ) and 26 stapp patients ( 74% ) were re - examined in the outpatient clinic . 
   neither inguinal nor port - site hernia occurred in either group . regarding immediate postoperative pain , there was a tendency for longer pain duration in the wound region after the stapp procedure ( ntapp , 5.6  5.5 days vs stapp 9.8  8.4 days ; p = .072 ) . 
   also stapp patients experienced greater wound pain intensity when they began to resume their regular daily activities after hospital discharge ( ntapp 2.7  2.1 vas vs stapp 4.4  1.9 vas ; p = .016 ) . 
   one patient in the ntapp group had chronic discomfort , with paresthesia in the groin region . 
   one patient in the stapp group developed postherniorrhaphy pain syndrome and remained on paid sick leave at home for approximately 2 months . at the time of the follow - up examination 
   , both groups achieved similar results in janda 's clinical test for abdominal wall mobility ( ntapp 4.7  0.5 vs stapp 4.1  1.1 ; p = .101 ) . 
   however , 7 ( 20% ) patients who underwent stapp repair noted a subjective deterioration in abdominal wall mobility in the questionnaire , whereas no patients who underwent ntapp repair had such an experience . 
   cosmetic satisfaction was equally high , with a vas score of 9.7  0.6 in the ntapp group and 9.6  0.7 in the stapp group ( p = .836 ) . 
   sick leave records showed that the ntapp group had a significantly shorter mean period of sick leave , compared with the stapp group ( ntapp 11.2  8.4 days vs stapp 24.1  20.1 days ; p = .02 ) . 
   notably , even with cessation of postoperative wound pain , 27 ntapp patients ( 54% ) and 32 ( stapp patients 91.4% ) remained on sick leave at the follow - up assessment ( p = .045 ) . 
   in the present study , only patients with uncomplicated inguinal hernias without strangulation or acute pain were included in the investigation , to avoid the possibility that memory of preoperative pain would influence the postoperative pain assessment . also needlescopic trocars and instruments , per se , 
   are not suitable for bowel resections and removal of any extensive tissue from the abdominal cavity . to avoid technical errors and the effects of the learning curve , 
   the operating surgeon in this study was experienced , having performed approximately 20 ntapp repairs with an 8-mm optical trocar and two 5-mm working trocars . before the study 
   , the same surgeon had also performed at least 20 single - incision laparoscopic surgeries for inguinal hernia or cholecystectomy . 
   the results presented in this study should therefore apply to cases involving common hernia and treatment by an experienced surgeon . for the assessment of perioperative surgical trauma to the abdominal wall 
   , we focused on the umbilical skin incision length and total operative time for each procedure . in the ntapp group , a larger ( 8-mm ) umbilical trocar 
   the purpose was to allow for gentle mesh insertion without inadvertent adherence of the folded parietene progrip mesh to itself within the trocar cannula . 
   still , the incisional trauma at the umbilicus in stapp patients was twice that in ntapp patients . 
   although we encountered only 1 stapp patient with postoperative hematoma , there is evidence that a longer surgical skin cut in single - incision laparoscopic surgery is associated with wound complications . 
   furthermore , the operative time for stapp repair of a unilateral hernia ( 85 minutes ) was also significantly longer on average than that required for ntapp ( 54 minutes ) or conventional tapp ( 60 minutes in our previous publication ) repair . 
   the increased operative time for stapp repair indicates an increase in technical difficulty without obvious benefits in surgical capability , as 2 stapp cases ( 5.7% ) in our study still needed an additional working trocar for the creation of a sufficient preperitoneal space . as mentioned in the literature , operative difficulties for single - incision laparoscopic surgery lie in the lack of triangulation and the restricted movement of surgical instruments . in this study , we did not use curved or articulating instruments to improve triangulation in the stapp procedure , as such instruments would add another factor of variation of surgical equipment between the 2 procedures . 
   the smaller jaws and lesser contact area would theoretically exert more force and tear tissue , particularly under the control of the nondominant left hand in our study . 
   some surgeons in our department prefer to perform ntapp repairs with one 5-mm optical trocar and two 5-mm working trocars , with mesh fixation via absorbable tacks and closure of the peritoneum via extracorporeally knotted running sutures . 
   particularly in such procedures , no fascial closure ( a potential source of postoperative wound pain ) was needed for the 5-mm trocar wounds . 
   such ntapp repair variation also seems to be safe and feasible , according to unpublished data . 
   concerning technique variations in single - incision laparoscopic surgery , one study group reported using a single skin incision with 3 separate adjacent fascia punctures in laparoscopic ventral hernia operations . 
   this single - incision multiport technique reduces incisional trauma on the abdominal wall , but preformed proximate fascia defects still have a greater potential to cause a  swiss cheese  hernia . apart from investigating the surgical trauma in ntapp and stapp repair , we investigated postoperative pain , mobility , and cosmesis of the abdominal wall , as well as length of sick leave . 
   we found that the ntapp procedure was able to further reduce immediate postoperative pain in wound regions . 
   these results of wound pain reduction in ntapp repair are in concurrence with available studies comparing pain experienced after needlescopic and conventional laparoscopic inguinal hernia repair . 
   in contrast , a current review referenced 4 available stapp trials and could not verify superiority in pain reduction over conventional tapp repair . 
   however , reduction of postoperative wound pain in patients who underwent ntapp did not significantly improve incidence of chronic groin pain . 
   such pain still occurred in 2% of our ntapp group , compared with 2.8% in the stapp group . 
   moreover , functional mobility of the abdominal wall is the result of intact motor activity and simultaneous load transfer . 
   scar tissues with less loading capacity at the umbilicus in the midline therefore suggests a mechanical mismatch in the latter component and predisposes the patient to a functional impairment of the abdominal wall . despite the greater extent of such scar tissue in the stapp group 
   , the groups regained equal abdominal wall mobility and satisfactory cosmetic results after an approximate observation time of 30 months . 
   taking into account the length of hospital stay added to the subsequent sick leave days , the total time until return to work in the ntapp group was half that in the stapp group . 
   it is also worth noting that more stapp than ntapp patients remained on sick leave , even with an absence of postoperative wound pain . 
   there are nonetheless multiple factors that influence the period of sick leave , including psychological factors related to the larger scar caused by stapp repair . 
   finally , such patient - related outcomes in pain , cosmetic satisfaction , and length of disability are motivation dependent and therefore are subjective measurements . 
   this effect is especially seen in our data on pain duration and sick leave time , with high standard deviations indicating more polarized responses . 
   in a direct comparison of 2 advanced techniques for laparoscopic tapp hernia repair , the ntapp procedure with smaller caliber trocars can further minimize surgical trauma to the abdominal wall tissue . 
   it also requires significantly less operating time than the stapp procedure , as it still adheres to the basic principles of triangulation in laparoscopic technique . in uncomplicated hernia repair , 
   the ntapp procedure has distinct advantages in the immediate postoperative phase in reduced postoperative wound pain and shorter sick leave . 
   however , it offers comparable long - term results in hernia recurrence , abdominal wall mobility , and cosmetic satisfaction . randomized controlled trials comparing ntapp , stapp , and conventional tapp repairs are still needed to validate the benefits of needlescopic surgery .
summary: background and objectives : in recent years , 2 modifications of laparoscopic transabdominal preperitoneal ( tapp ) inguinal hernia repair  needlescopic ( ntapp ) surgery and single - port ( stapp ) surgery  have greatly improved patient outcomes over traditional approaches . for a comparison of these 2 modifications 
   , we sought to investigate and compare the extent of surgical trauma and postoperative consequences for the abdominal wall in these two procedures.methods:in a retrospective study , 50 ntapp and 35 stapp procedures occurring at a community hospital from november 1 , 2009 , through july 31 , 2012 were reviewed . 
   intraoperative data , including length of the umbilical skin incision and operative time , were recorded . 
   a follow - up evaluation included investigation of hernia recurrence , postoperative pain , abdominal wall mobility , cosmetic satisfaction , and period of sick leave.results:the mean umbilical skin incision was 13  4 mm in ntapp vs 27  3 mm in stapp ( p < .001 ) . 
   the ntapp procedure required less operating time than the stapp procedure ( 54.8  16.9 minutes vs 85.9  19.7 minutes ; p < .001 ) . 
   the mean immediate postoperative pain score on the visual analog scale was 2.7  2.1 in the ntapp group and 4.4  1.9 in the stapp group ( p = .016 ) . 
   in addition , patients who underwent ntapp had a shorter period of sick leave ( 11.2  8.4 days vs 24.1  20.1 days ; p = .02 ) . at the follow - up evaluation after approximately 30 months , abdominal wall mobility and cosmetic satisfaction were equally positive , with no hernia recurrence.conclusion:in patients with uncomplicated inguinal hernia , the ntapp procedure , with less surgical trauma and operating time , has distinct advantages in reduction of immediate postoperative pain and sick leave time .