The development of an incisional hernia at the trocar-site after laparoscopy is relatively uncommon with a reported incidence rate of approximately 1 % [1–10]. This complication, first noted by Fear in 1968, can result in significant morbidity to the patient often requiring operative interventions [11–13].

Although studies have sought to study the pathogenesis, prevalence, and risk factors that may contribute to the occurrence of trocar-site hernia, quality data are scarce due to the difficulty in conducting studies with adequate power and follow-up [6]. Thus far, several risk factors have been proposed for the occurrence of trocar-site hernias. These include wound infection, obesity, patient age, and the location, type, and size of the trocar employed [1, 2, 4, 14–19].

Whereas the need for closure of trocar sites and the ideal technique for achieving closure are debated, the current prevailing consensus is that all fascial defects greater than 10 mm should be closed [20]. Single-port laparoscopy (SPL) employs a 1.5- to 2.5-cm umbilical incision for insertion of the working port. Whether the larger incision results in an increased rate of trocar-site hernias is unclear as open operations with larger fascial incisions have been associated with hernia rates as high as 20 % [21]. Therefore, we undertook this study to measure the incidence of trocar-site hernia with our SPL experience.

We studied our bariatric population due to their robust follow-up compared with the general surgical population. These patients are usually followed closely to monitor their nutritional and weight loss status.

Materials and methods

We conducted an institutional review board-approved, retrospective study of all laparoscopic sleeve gastrectomy (LSG) and adjustable gastric band placement (LAGB) procedures performed at our Bariatric Center of Excellence from 2001 to 2011. We started offering SPL bariatric operations to our patients in 2008.

There were 734 cases performed, 53 of which were excluded because of their relatively short (<1 month) or missing follow-up at the time of this review. In addition, we excluded patients with a history of an abdominal operation and patients who presented with ventral hernias. Patient demographics, comorbidities, operation type, and postoperative outcomes, including weight loss and complications, were noted. Patient charts and imaging studies were reviewed to confirm the presence or absence of trocar-site hernias in all patients.

The decision to offer a patient a SPL operation versus a multiport operation was made by the surgeon in discussion with the patient. All fascial defects created by trocar size greater than 12 mm were closed with absorbable suture—usually 2–0 Vicryl (Ethicon, Cincinnati, OH) under direct visualization. Fascial closure was not performed for 5-mm trocar sites.

We used two different techniques for SPL. In our original technique, we created a 1.5- to 2.5-cm skin incision with the development of a subcutaneous pocket. Once the anterior fascia was reached, Veress needle was used to insufflate the abdomen. A 5-mm trocar was then placed left laterally and a 15-mm trocar was placed right laterally. After the adjustable band was introduced through the 15-mm trocar, we removed the trocar and closed the fascia in interrupted fashion with absorbable suture. We then introduced three more 5-mm ports through the same incision [22]. Twenty-two of our SPL cases were performed using this technique. For the rest of our SPL cases, we used the Hasson’s technique and placed SILS™ port (Covidien, Mansfield, MA) at the umbilical site under direct visualization.

Multiport LSG was performed with five trocars: three 5 mm and two 12 mm in diameter. Multiport LAGB was performed with three 5 mm, one 12 mm, and one 15 mm trocars. All trocars used were noncutting (bladeless). Access to the abdomen was gained in the majority of multiport cases with the use of Endopath® Xcel® trocars with Optiview Technology (Ethicon).

All data analysis was performed with SPSS version 17 for Windows (SPSS Inc., Chicago, IL). Continuous variables and categorical variables were compared using Student’s t test and Chi-square test respectively. Cox regression was used to perform multivariate analysis of clinical factors that may be associated with trocar-site hernia occurrence.

Results

We reviewed 163 SPL operations (57 LSG, 106 LAGB) and 513 multiport operations (53 LSG, and 460 LAGB). The demographics of the SPL group and the multiport group and their postoperative outcomes in terms of length of stay (LOS) and weight loss were similar. However, the average body mass index (BMI) of the multiport group was higher than the SPL group (43.5 ± 5.3 vs. 45.8 ± 7.7, p < 0.01). In addition, more wound infections were noted in the SPL group (Table 1).

Table 1 Comparison of patients who underwent SPL versus multiport bariatric operations
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The median follow-up for the SPL group was 7 months (range, 1–35) and 18 months for the multiport group (range, 1–72). The mean follow-up for the SPL group was 11.3 ± 9.0 and 23.9 ± 20.2 months for the multiport group. Whereas the average follow-up of the SPL group was shorter than the multiport group, 45 % (74/163) of the patients in the SPL group had a follow-up ≥12 months.

The overall incidence of hernia occurrence rate in the multiport group was 0.6 % (3/513) compared with 0.6 % (1/163) for the SPL group (p = 0.967). The three trocar-site hernias in the multiport group occurred after LAGB at 1, 13, and 18 months. The trocar-site hernia in the SPL group was discovered at 8 months postoperatively after LSG using the SILS™ port. All trocar-site hernias occurred at the 15-mm port site for the multiport group. Hernias were discovered during follow-up visits and confirmed by imaging studies before an elective repair was performed.

The comparison of patients who developed trocar-site hernia versus those who did not is shown in Table 2. Patient age, BMI, SPL operation, procedure type, comorbidities, and postoperative outcomes between those who developed trocar-site hernia and those who did not were similar. On multivariate analysis, we found that patient age, BMI, SPL operation, procedure type, hypertension (HTN), obstructive sleep apnea (OSA), hyperlipidemia (HLD), and the degree of postoperative weight loss were not associated with the occurrence of trocar-site hernia (Table 3).

Table 2 Comparison of patients who developed trocar-site hernia versus those who did not
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Table 3 Cox proportional hazard ratio of clinical factors in relation to trocar-site hernia occurrence
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Discussion

The reported incidence of trocar-site hernia after laparoscopy is low. In a recent review, the incidence of trocar-site hernia after laparoscopy was 0.5 % on a pooled analysis of 23,440 patients [23]. Although many different types of laparoscopic operations have been studied, the most common gastrointestinal operation studied thus far has been laparoscopic cholecystectomy [20].

Attempts to identify clinical factors associated with the occurrence of trocar-site hernia have been challenging due to the low incidence of trocar-site hernia and the difficulty in obtaining a robust follow-up. Furthermore, diversity of the operations studied, variations in closure techniques, and the different types of trocars available have made uniform recommendations on avoidance of trocar-site hernia difficult. Nevertheless, some risk factors have been proposed as increasing the risk of trocar-site hernias, including patient age, obesity, wound infection, closed entry into the abdomen, conical shape trocar, and the use of trocar size greater than 12 mm [1, 2, 9, 10, 16, 17, 23–26]. In a study of laparoscopic cholecystectomy by Uslu et al. [16], BMI >28 was identified as a risk factor for trocar-site hernia.

In general, studies of trocar-site hernia in bariatric populations have yielded low rates of trocar-site hernia occurrence in line with other laparoscopic operations [18, 24, 27, 28]. However, different bariatric procedures may have different risks of trocar-site hernias. LAGB and LSG may have a higher risk of trocar-site hernia due to specimen extraction and insertion of device compared with laparoscopic Roux-en-Y gastric bypass (LRYGBP).

In the literature, Chiu et al. [27] reported 0.3 % (2/610) prevalence of trocar-site hernia, whereas Rosenthal et al. [28] reported a hernia rate of 0.2 % (2/849) after LRYGBP. The rates of trocar-site hernia after LAGB and LSG in the literature are slightly higher. Susmallian et al. [24] reported three trocar-site hernias out of 459 cases for a rate of 0.6 % for LAGB; Arias et al. [29] reported a 0.7 % incidence of trocar-site hernias for LSG. These studies suggest that bariatric operations can be performed with a low rate of trocar-site hernia occurrence.

SPL has been shown to be safe and effective compared with multiport laparoscopy for several types of procedures in randomized trials [30–33]. However, whether SPL increases the risk of trocar-site hernia when used for bariatric procedures is not known. Our data suggest that the use of SPL in bariatric surgery does not increase the risk of a trocar-site hernia. Additionally, in our study, patient age, BMI, HTN, OSA, HLD, and the degree of postoperative weight loss were not associated with the occurrence of trocar-site hernia. We could not perform multivariate analysis for diabetes or wound infection, because none of the patients who developed trocar-site hernia were diabetic or experienced wound infection. However, we did not detect association between wound infection and diabetes with the trocar-site hernia occurrence on our univariate analysis.

One of the limitations of the study was that the average BMI of the multiport group was higher than the SPL group by 2 kg/m2. Although this may be not clinically significant, it does reflect a selection bias in our practice. Additionally, more LSG were performed in the SPL group compared with the multiport group in our study. However, neither LSG nor LAGB were independent risk factors for developing trocar-site hernia on our analysis.

We started offering SPL to our patients in 2008. Therefore, the average follow-up for the patients in the SPL group was shorter than the multiport group. To account for this, we performed a subgroup analysis and found that 45 % (74/163) of our patients had a follow-up of greater than 12 months. There were no hernias seen in those patients.

Finally, our technique underwent evolution during the study period. Our initial technique for SPL required multiple fascial incisions through a single skin incision and was used for 22 of our cases. The rest of the cases were performed with a single fascial incision with the placement of the SILS™ port. The single hernia in the SPL group occurred with the use of the SILS™ port. Because there was only one trocar-site hernia noted in the SPL group, we are not able to make a meaningful conclusion about whether the difference in SPL technique contributes to the occurrence of trocar-site hernia.

Conclusions

Our data suggest that a low rate of trocar-site hernia can be achieved with the use of SPL in bariatric surgery. Longer follow-up is needed to determine whether the result of this study is sustainable. Meticulous fascia closure is imperative in SPL to ensure that the cosmetic advantages of SPL are not compromised by increased trocar-site hernia rate.