most of these incisions were associated with multiple morbidities , such as surgical - site infections , incisional hernia , postoperative pain , and prolonged hospitalization .
unsatisfied with these morbidities , surgeons sought ways of minimizing their incision length without compromising the integrity of the surgical procedure performed within the intra - abdominal cavity . with the use of smaller incisions facilitated by laparoscopy ,
it was hoped that single - incision laparoscopy would add additional cosmesis to conventional laparoscopy .
the concept of single - trocar laparoscopy is not new because it has been within the domain of gynecologists for several years .
reports of single - port laparoscopic sterilization were documented in the 1960s . in 1 report in 1969 ,
single - trocar laparoscopy was performed with a 12-mm operative laparoscope with 1 operative channel . despite these pioneering efforts ,
single - trocar laparoscopy was not widely embraced by the surgical community because of the lack of appropriately designed equipment . with improvements in optics and technology , single - trocar appendectomy and cholecystectomy
the term single - site laparoscopic surgery was coined by the laparoendoscopic single - site surgery consortium for assessment and research for uniformity in academic publications in 2008 .
single - incision laparoscopic surgery ( sils ) represents a unique twist in minimally invasive surgery .
this novel surgical approach was born out of the quest for scarless , highly cosmetic surgery .
the primary benefit of sils seems to be cosmetic related ; the umbilicus is the preferred incision site because the scars can be easily hidden .
other reported benefits are improved postoperative pain and a quicker return to normal activities of daily living .
the concept of a single - incision approach has been adopted for various surgical techniques ranging from sleeve gastrectomy , colectomy , and adrenalectomy to nissen fundoplication . as
sils becomes more widely adopted , the incidence of port - site hernias ( pshs ) becomes an important consideration in the overall risk - benefit discussion with the patient .
this study aims to determine the incidence of pshs after sils at a single institution performing a variety of sils operations .
we performed a retrospective study with prospective data collection of all sils procedures performed in a high - volume tertiary center in bronx , new york , between may 2008 and may 2009 .
the institutional review board approved the study , and informed consent was obtained from all patients .
we defined psh as the development of a hernia at the single - incision skin site .
psh may be further characterized into early ( dehiscence of fascial planes and peritoneum ) or late ( dehiscence of fascial plane with intact peritoneal hernia sac ) .
the exclusion criteria were as follows : history of mesh placement in the umbilical or upper abdomen ; patients receiving steroid therapy , heparin , coumadin : ( bristol - myers squibb , princeton nj , usa ) , plavix ( clopidogrel ) : ( bristol - myers squibb / sanofi , princeton nj , usa ) , or aspirin ; body mass index ( bmi ) > 50 kg / m ; and appendicitis present for > 36 hours .
in addition , we excluded any patient who had a conversion from an sils approach to a standard laparoscopic approach .
all patients operated on between may 2008 and february 2009 underwent a multiport technique ( figure 1 ) .
this consisted of standard ports placed through the umbilical skin incision into the fascia and used multiple points of fascial entry through the single skin incision .
the 3-trocar sils port ( covidien , north haven , connecticut ) ( figure 2 ) was introduced in march 2009 , and all procedures performed after that date used this port .
when the sils procedures were performed , the patients were placed in either a supine or modified lithotomy position , depending on the surgeon 's preference . with the patient under general anesthesia , a 2-cm vertical transumbilical skin incision was made . in the early stage of the study ,
access to the abdomen was accomplished by introducing three 5-mm trocars through separate fascial punctures but contiguous skin incisions . at the end of the procedure
, the separate fascial incisions were connected to form a single incision to facilitate the extraction of the resected specimen . with the introduction of the sils port ,
once pneumoperitoneum was achieved , three 5-mm ports were inserted through the sils port , and one of the 5-mm ports could be changeable to a 12-mm port . to prevent port - site or incisional
the skin incision was infiltrated with a local anesthetic agent ( bupivacaine ) and was approximated with a running subcuticular no .
postoperatively , all patients were examined during their scheduled appointments 2 to 4 weeks after the procedure and then subsequently at 3 months depending on the procedure performed .
all patients were contacted between 30 and 36 months after the procedure to return to the office for an additional evaluation . during this visit , each patient was questioned and examined by an attending surgeon looking specifically for evidence of port - site incisional hernia .
patients who were found to have clinical evidence of incisional hernia underwent repair with mesh in all cases .
statistical analysis was performed with graphpad prism statistical software ( graphpad , san diego , california ) .
when the sils procedures were performed , the patients were placed in either a supine or modified lithotomy position , depending on the surgeon 's preference .
with the patient under general anesthesia , a 2-cm vertical transumbilical skin incision was made . in the early stage of the study , access to the abdomen was accomplished by introducing three 5-mm trocars through separate fascial punctures but contiguous skin incisions . at the end of the procedure , the separate fascial incisions were connected to form a single incision to facilitate the extraction of the resected specimen . with the introduction of the sils port ,
once pneumoperitoneum was achieved , three 5-mm ports were inserted through the sils port , and one of the 5-mm ports could be changeable to a 12-mm port . to prevent port - site or incisional
the skin incision was infiltrated with a local anesthetic agent ( bupivacaine ) and was approximated with a running subcuticular no .
postoperatively , all patients were examined during their scheduled appointments 2 to 4 weeks after the procedure and then subsequently at 3 months depending on the procedure performed .
all patients were contacted between 30 and 36 months after the procedure to return to the office for an additional evaluation . during this visit , each patient was questioned and examined by an attending surgeon looking specifically for evidence of port - site incisional hernia .
patients who were found to have clinical evidence of incisional hernia underwent repair with mesh in all cases .
statistical analysis was performed with graphpad prism statistical software ( graphpad , san diego , california ) .
a total of 211 patients underwent single - incision laparoscopic procedures during the study period .
table 1 show the patients ' demographic data and indications for sils . for the purpose of this study , patients were divided into 2 groups 
the 2 groups were identical in terms of age , bmi , and type of trocars used for the procedures .
demographic characteristics of patients who underwent sils and indications for sils procedure gerd = gastroesophageal reflux disease .
the mean operative time for all cases was 40 minutes ( range , 21120 minutes ) .
the mean estimated blood loss was 30 ml ( range , 10150 ml ) . in 1 patient an additional port was placed because of bleeding .
multiports were used in 98 cases , and in the remaining patients , the sils port was used ( table 2 ) .
type of sils procedures performed at 36 months , there was a 97% follow - up rate ( n = 205 ) .
psh developed in 6 patients , requiring surgical repair with mesh ( psh rate of 2.8% [ n = 6 ] ) ( table 4 ) .
the interval between the sils procedure and diagnosis of psh varied from 24 months to 36 months ( mean , 28.4 months ) .
a subset analysis of the hernias showed that among patients who underwent sils cholecystectomy , psh was more common in patients who had multiport bladed trocars ( 2.5% , 2 of 98 patients ) .
this finding was in sharp contrast to that in bariatric patients , in whom psh occurred exclusively among sils port patients with non - bladed trocars ( 3.5% , 4 of 113 patients ) ( table 3 ) .
incidence of psh by procedure and sex subset of reporting variables among patients with psh based on trocar type and bmi p = .11 ( 95% confidence interval , 0.01170.0621 ) .
in addition , the pattern of psh formation was different between bariatric and nonbariatric patients .
all pshs in bariatric patients occurred after the use of bladed trocars , whereas among nonbariatric patients , psh followed the use of non - bladed trocars .
sils appears to be finding greater acceptance and adoption among general surgeons . over the past 5 years
, the application of sils has expanded to a growing number of surgical procedures . with this increasing adoption , we have learned a great deal about the benefits sils has to offer , such as improved cosmesis , decreased postoperative pain , and a quicker return to general activity .
however , because it is still a relatively new technique , long - term outcomes have yet to be determined .
one of these long - term outcomes is port - site incisional hernia . in the laparoscopic literature ,
port - site incisional hernias typically occur as a late rather than an early postoperative complication , with a mean time to diagnosis of 9.2 months . among the existing studies in the english - language literature ,
few have documented psh beyond 1 year . yet , there is mounting evidence to suggest that this complication occurs as late as 2 years and beyond . in our study
we have > 2 years ' follow - up , which should encompass all postoperative pshs .
our study period , which began in may 2008 , is relatively early in the lifespan of sils . at that time
, we were still developing our preferred technique within our own practice ; moreover , no sils port existed .
therefore multiports were used within the umbilicus to achieve the desired cosmetic effect of a single incision .
after the development of the sils port in 2009 , it became our preferred sils access technique , largely because of its ability to prevent air leak and its direct visual insertion into the abdominal cavity . because many surgeons currently use the multiport sils technique
, we believed that it was important to include both patient populations in our study .
we also recorded a similar rate of hernias among patients with multiports and those with sils access ports . in this series
we believe that by connecting these fascial incisions and turning them into 1 incision , the defect may be effectively repaired , thus reducing the risk of psh . in this study
this is comparable with other reported series . of the patients in our series with pshs , none had any obstructive symptoms
this is not unusual because other studies have shown that most patients have minimal symptoms , particularly those with the delayed - onset type .
six patients in our series were lost to follow - up . to the best of our knowledge ,
we are unaware of any late complications occurring in these patients . several factors , which can be categorized into operative or patient - related factors , are known to contribute to the development of psh .
most laparoscopic surgeons agree that the diameter of the cannula or port is the single most common cause of port - site incisional hernia . because , in sils procedures , the fascial defect is larger than that in conventional laparoscopy and , in addition , multiple defects are converted to a single larger fascial defect , sils procedures are inherently at risk of psh development .
although it is unclear whether this technical maneuver translates into actual psh , there are several reports in the literature that suggest that prolonged manipulation coupled with reinsertion of the port may be associated with an enhanced risk of psh . in a multivariate analysis that examined the factors associated with psh , uslu et
al determined that a prolonged duration of surgery is associated with increased risk of psh .
other reports suggested that the act of extending an incision for the purpose of retracting a specimen was associated with an increased risk of psh .
the type of trocar used is also widely believed to be an important determinant of psh .
bladed trocars generally require less force to insert but have a higher incidence of complications , such as bleeding , pain , and hernias .
conversely , bladeless trocars are radially dilating and associated with less pain and bleeding . in our experience
we believe that because psh occurs in both groups of patients , other factors may be involved ( p = .11 ; 95% confidence interval , 0.01170.0621 ) .
it is hoped that the new generation of hybrid trocars will address some of the limitations of traditional trocars .
other authors have reported on a variety of patient - related factors that are associated with an increased risk of psh , such as the presence of pre - existing umbilical hernia , diabetes mellitus , chronic obstructive pulmonary disease , arterial insufficiency , immune deficiency , malnutrition , smoking , infection , obesity , and sex .
nassar et al observed that 12% of patients undergoing laparoscopic cholecystectomy had pre - existing umbilical or paraumbilical defects , of which 84% were asymptomatic . although these defects were closed primarily , psh occurred in 1.8% of patients .
interestingly , 25% of these hernias occurred in patients with pre - existing hernias with fascial closure at the time of the study .
azurin et al reported similar findings . in a retrospective review of 1300 patients who underwent laparoscopic cholecystectomy , azurin et
al observed that 9 of the 10 patients in whom pshs developed were found at the time of surgery to have umbilical hernias , which were repaired at the time of surgery . in our series 2
patients had umbilical hernias , but psh did not develop in either of these patients .
studies have shown that obesity is a predisposing factor for psh ; however , definitive evidence in support of the effect of bmi on the incidence of psh is lacking .
one study showed evidence suggesting that a sudden weight gain rather than obesity per se may be the predisposing factor for hernia formation after surgery .
however , only 1 study to date has reached significance in a multivariable analysis , and other studies have shown no statistical difference . in our study 50% of the patients with psh were morbidly obese ( bmi > 40 kg / m ) and 83% were obese ( bmi > 30
although we believe obesity may play a role in the development of psh , because of the small size of our study , conclusions can not be drawn from our observations .
other authors indicated that they believe that because of the substantially thickened preperitoneal space and increased intra - abdominal pressure , there is a tendency to improperly close the fascial defect in obese patients .
though not specifically addressed in our study , other studies that compared sils with standard multiport laparoscopy have shown similar total adverse events but with an increased psh rate among the sils patients ( 8.4% for sils vs 1.2% for multiport laparoscopy ) .
there is conflicting evidence in the literature about the role of sex in the pathogenesis of psh . in some reports ,
male sex appeared to be associated with a higher incidence of psh , yet in another study , the incidence was higher among women on univariate analysis but not on multivariate analysis .
all the patients in our series in whom psh developed were women . although the role of sex in the incidence of psh in the literature is mixed , in our experience , it appears that the factors responsible for psh go beyond sex and are multifactorial .
sex appears to be a source of bias in our study because most patients undergoing cholecystectomy and bariatric surgery are women , which may explain the female bias of psh in our study .
some reports have implicated wound infection in the pathogenesis of umbilical psh . as shown by callery et al ,
most umbilical incisions are infected during laparoscopic procedures and the subsequent development of late - onset  type pshs may be related to this initial infection . in addition , a recently published randomized study investigating the effect of prophylactic topical rifamycin showed a reduction in the incidence of incisional hernia among patients in the study group , thus validating the observation of callery et al .
other reports suggest that the placement of a drain through a port site may be a risk factor for psh .
there is evidence to support the notion that the site of trocar placement may have a bearing on the subsequent development of psh . as
azurin et al and other authors have shown , most pshs developed in the midline rather than at the lateral site .
plaus and duron et al stated that because there is overlapping of muscles and 2 fascial layers , the lateral site is less susceptible to dehiscence .
the hernia and its subsequent mesh repair often negate the cosmetic benefit offered by this technique .
the repairs in all patients necessitated enlargement of the skin incision to adequately expose all hernia edges and provide an adequate repair .
once the skin incision was enlarged , it extended beyond the umbilical borders and was no longer contained within the scar of the umbilicus , and it was therefore visible .
it remains important to explain this potential complication to patients who are making the decision to undergo sils based primarily on the cosmetic result .
as our study has shown , the development of psh is a major setback for a procedure that is popularized based on its cosmetic superiority .
sils is still evolving , and it is unclear whether it will replace conventional laparoscopy in the future .
further studies are required to answer important questions about its safety profile and long - term outcome data .
 background and objectives : single - incision laparoscopic surgery is gaining popularity among minimally invasive surgeons and is now being applied to a broad number of surgical procedures . 
 although this technique uses only 1 port , the diameter of the incision is larger than in standard laparoscopic surgery . 
 the long - term incidence of port - site hernias after single - incision laparoscopic surgery has yet to be determined.methods:all patients who underwent a single - incision laparoscopic surgical procedure from may 2008 through may 2009 were included in the study . 
 single - incision laparoscopic surgical operations were performed either by a multiport technique or with a 3-trocar single - incision laparoscopic surgery port . 
 the patients were seen at 30 to 36 months ' follow - up , at which time they were examined for any evidence of port - site incisional hernia . 
 patients found to have hernias on clinical examination underwent repairs with mesh.results:a total of 211 patients met the criteria for inclusion in the study . 
 the types of operations included were cholecystectomy , appendectomy , sleeve gastrectomy , gastric banding , nissen fundoplication , colectomy , and gastrojejunostomy . 
 we found a port - site hernia rate of 2.9% at 30 to 36 months ' follow-up.conclusion:port-site incisional hernia after single - incision laparoscopic surgical procedures remains a major setback for patients . 
 the true incidence remains largely unknown because most patients are asymptomatic and therefore do not seek surgical aid . 
INTRODUCTION
METHODS
Patient Positioning
Procedure
Statistical Analyses
RESULTS
DISCUSSION
CONCLUSION