Surgery for Obesity and Related Diseases 11 (2015) 248–258

Review article

Single-incision laparoscopic bariatric surgery: a systematic review Carlos Moreno-Sanz, M.D., Ph.D., F.A.C.S.a,*, Antonio Morandeira-Rivas, M.D., Ph.D.a, Cristina Sedano-Vizcaino, M.D.a, Jose María Tenías-Burillo, M.D., Ph.D.b, Carmén Román-Ortíz, M.D., Ph.D.b, Juan Bautista Muñoz de la Espada, M.D., Ph.D.a a

Department of Surgery, La Mancha Centro General Hospital, San Juan, Spain Research Support Unit, La Mancha Centro General Hospital, San Juan, Spain Received August 17, 2013; accepted November 27, 2013

b

Abstract

Background: Single-incision laparoscopic surgery has sparked a great deal of interest in the surgical community in recent years, including bariatric surgery. However, we still do not definitively know if this type of surgical approach provides benefits over conventional techniques without increasing morbidity and mortality. Objective: To evaluate the safety and efficacy of single-incision laparoscopic bariatric surgery (SILBS) compared with conventional laparoscopic bariatric surgery (CLBS). Materials and Methods: We searched the most important databases. Randomized clinical trials and observational studies comparing SILBS with CLBS were included. This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and MetaAnalyses recommendations. Results: Fourteen studies complied with the inclusion criteria for our analysis, which included 2357 patients (1179 SILBS group versus 1178 CLBS group). The duration of surgery was longer in the SILBS group and no major intraoperative complications were observed in these series. A small improvement in postoperative pain was indicated in the SILBS group. The overall morbidity rate was 5% in the SILBS group and 4.8% in the CLBS. There was 1 perioperative death in 1 study, which occurred in an adjustable gastric banding (AGB) group, at .1% of all cases of AGB and .005% of all SILBS cases. When cosmesis was evaluated, patients in the SILBS group were more satisfied with the scar outcome. Conclusion: SILBS is a feasible technique to use in selected patients. However, there is insufficient evidence to recommend its widespread use compared with a conventional approach. More studies are needed to analyze the safety of this technique and its possible benefits. (Surg Obes Relat Dis 2015;11:248–258.) r 2015 American Society for Metabolic and Bariatric Surgery. All rights reserved.

Keywords:

Single-incision adjustable gastric banding; Single-incision sleeve gastrectomy; Single-incision; Roux-en-Y gastric bypass; Single-incision bariatric surgery; Systematic; review

The expansion of new minimally invasive surgical (MIS) techniques and technologies in recent years has been based on achieving one of the primary “ideal” goals of modern surgery: surgery without visible scars. Surgery involving zero or minimal trauma to the abdominal wall would, at *

Correspondence: Carlos Moreno-Sanz, Department of Surgery, La Mancha Centro General Hospital, Avd. de la Constitución nº 3, 13600 Alcázar de San Juan (Ciudad Real), Spain. E-mail: [email protected]

least in theory, imply all the advantages of MIS. In this context, natural orifice transluminal endoscopic surgery could be considered as a paradigm of this type of development, although despite proven feasibility, its widespread implementation has been limited by a lack of development [1]. However, the innovation resulting from research into natural orifice transluminal endoscopic surgery techniques has allowed for the development of current surgical techniques geared toward the concept of reducing access

1550-7289/14/$ – see front matter r 2015 American Society for Metabolic and Bariatric Surgery. All rights reserved. http://dx.doi.org/10.1016/j.soard.2013.11.013

Single-incision Bariatric Surgery / Surgery for Obesity and Related Diseases 11 (2015) 248–258

surgery. A series of bridge technologies have facilitated this development under high standards of safety and efficacy, with single-incision laparoscopic surgery (SILS) being the most attractive of the techniques currently available. SILS has been used for various abdominal procedures including cholecystectomy [2], appendectomy [3], and colectomy [4,5] and recently this technique has also been applied to bariatric surgery [6]. In an attempt to improve the results of bariatric surgery, a number of single-incision laparoscopic bariatric surgery (SILBS) procedures have been developed, including adjustable gastric banding (AGB), sleeve gastrectomy (SG), and Roux-en-Y gastric bypass (RYGB) [7]. The objective of this review was to evaluate the feasibility and safety of SILBS and compare its potential advantages with conventional laparoscopic bariatric surgery (CLBS). Materials and Methods

Results We identified a total of 262 studies for review based on title and abstract. After excluding duplicated articles and those that did not comply with the inclusion criteria, we obtained a total of 20 studies that were reviewed in depth. Finally, 4 studies did not contain a control group and 2 were review articles, all of which were excluded. The flow chart of this selection process is summarized in Fig. 1. Fourteen studies with a total of 2357 patients, 1179 in the SILBS group and 1178 in the CLBS group, were included for qualitative synthesis [11–24]. These included 13 cohort studies [11–19,21–24] and 1 RCT [20] (Table 1). Quality of studies The general characteristics of the studies are summarized in Table 1. There was only 1 RCT, published by Lakdawala et al. [20], a preliminary study comparing 50 single-incision and 50 conventional SGs. This study had no adequate

This systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations [8]. Search parameters We took into account all studies published between 1985 and February 2013, with no limitations based on the language of publication. The standard major medical databases were accessed: Embase, PubMed, and Cochrane Central Register of Controlled Trials. In our searches, we used the MeSH “bariatric surgery,” the word roots “endoscop*,” “laparoscop*,” and “laparoendoscop*,” and the keywords “single incision,” “single site,” “single port,” “single access,” “single trocar,” “one trocar,” “one port,” “one wound,” “transumbilical,” “embryonic,” and “embryologic.” Study selection and data collection Randomized controlled trials (RCTs) and observational studies comparing SILBS with CLBS were included. We also reviewed the reference lists of these articles to find additional information. Duplicated publications and review articles were excluded. The results from each study were transferred into our data set by 2 independent reviewers (A. M-R., C. S-V.), and a third reviewer (C.M-S.) collaborated for a final decision in the case of any discrepancies. We assessed the methodologic quality of all included studies according to the Cochrane methodology for RCTs and the Newcastle-Otawa Quality Assessment Scale for observational studies [9,10]. The primary objective of our analysis was to evaluate feasibility and safety of SILBS and to compare its potential benefits over CLBS.

249

Fig. 1. Study flow chart.

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Table 1 General characteristics of the studies Technique/Author Adjustable gastric banding Nguyen et al. [11] Saber et al. [12] Raman et al. [13] Ayloo et al. [14] Chakravartty et al. [15] Vithiananathan et al. [16] Gawart et al. [17] Schwack et al. [18] Sleeve gastrectomy Saber et al. [19] Lakdawala et al. [20] Park et al. [21] Delgado et al. [22] Roux-en-Y gastric bypass Huang et al. [23] Lee et al. [24]

Nº patients SILBS/CLBS Design

NOS

Age (yr) SILBS/CLBS Gender SILBS/CLBS

BMI SILBS/CLBS

23/23 15/12 24/24 25/121 46/46 10/20 48/50 739/589

OR/C-M OP OR/C-M OP OR/C-M OR/C-M OP OR/C-M

****** ****** ******* ****** ******* ******* ***** *******

47/50 49.7/40.5 39.7/40.2 37/44 (P ¼ .002) 44*/47* 36.5/37.5 36.8/38.4 40/41.1

6♂–17♀ / 6♂–17♀ 1♂–14♀ / 0♂–12♀ 0♂–24♀ / 0♂–24♀ 3♂–22♀ / 12♂–109♀ 7♂–39♀ / 4♂–42♀ 1♂–9♀ / 2♂–18♀ 3♂–45♀ / 0♂–50♀ 233♂–477♀ / 215♂–369♀

39/40 41.3/39.6 41.7/41.4 46/47 43.1*/44.4* 41.8/42.5 43.2/48.3 (P o .0001) 42.8/44.8

14/12 50/50 25/9 20/22

OP RCT OP OP

****** NA ****** *******

44.2/43.1 26*/28* 46.8/47.9 46/50

7♂–7♀ / 5♂–7♀ 10♂–40♀ / 11♂–39♀ 2♂–23♀ / 1♂–8♀ 5♂–15♀ / 7♂–15♀

53.8/52.6 41*/43* 47.1/48.5 40.1/40.6

40/100 100/100

OP OR

****** 30.6/34.09 ******* 34.3/35.6

4♂-36♀ / 30♂-70♀ 30♂-70♀ / 26♂-74♀

41.1/44.1 (P ¼ .025) 43.2/44.2

BMI ¼ body mass index; NA ¼ not applicable; NOS ¼ Newcastle-Ottawa Quality Assessment Scale for cohort studies; OP ¼ observational prospective study; OR ¼ observational prospective study; OR/C-M ¼ observational retrospective case-matched study; RCT ¼ randomized controlled trial; SILBS ¼ single incision laparoscopic bariatric surgery bariatric surgery. Data are expressed as mean value, except *median.

description of the random sequence generation and allocation concealment, and participants and evaluators were not blinded. However, patient baseline characteristics, including body mass index (BMI), were comparable between the intervention and the control group and all the patients reached the 6-month follow-up period expected in this pilot study. There were 13 observational studies comparing SILBS and CLBS. The use of exclusion criteria in some studies in the SILBS group may have resulted in the presence of selection bias. Two studies found differences in BMI, which may affect the comparability of cohorts [17,23]. Furthermore, only 4 studies analyzed the possible effect of confounding factors such as the surgeons’ learning curve with SILBS [16,17,22,24] or patient BMI [22] and only did so for the outcome variable of operative time. Also, 6 of these cohort studies were retrospective [11,13,15,16,18,24] and most studies examined only short-term results (Table 2). Age, sex, and body mass index Mean/median age in all studies was r50 years, with a majority of female patients (72.5%). In general, participants were of comparable values for baseline characteristics (Table 1). No significant differences were observed in terms of age, BMI, or sex ratio between patients undergoing SILBS and CLBS in the majority of the studies. However, patients in the studies by Ayloo et al. [14] and Huang et al. [23] were significantly younger. In addition, Gawart et al. [17] and Huang et al. [23] found higher BMI values in the CLBS group (P o .05).

Procedures and exclusion criteria for SILBS The SILBS procedures performed were LAGB (n ¼ 930), SG (n ¼ 109) and RYGB (n ¼ 140). Exclusion criteria varied between studies. A BMI higher than 50–60 kg/m2 [11,13,16,23], previous abdominal surgery [11,16,19–24], the presence of an incisional hernia [13,16,18], or a xiphoid–umbilicus distance longer than 20 cm were the most commonly used criteria [18]. SILBS surgical devices and technical details Results for surgery characteristics are summarized in Table 2. A commercial single-port device was used in 7 studies [13,15,17,19–22]. The most commonly used device was SILSTM (Covidien, Autosuture, Hamilton, Bermuda) [19–22]. Multiple trocars placed through a single skin incision were used in all other cases [11,12,14,16,18, 23,24]. All SG procedures were performed using a singleport device [19–22], and a multiport technique was always used for RYGB surgeries [23,24]. All studies, with the exception of Lee et al. [24], used at least 3 ports/trocars (5,5,5 or 12–15 mm) placed through the single-access device or the single cutaneous incision. Procedures in the CLBS group were predominantly performed with a 4–5 conventional trocar approach [11,13,15–18,20–23]. A wide spectrum of laparoscopes were used, with a predominance of 5-mm laparoscopes with angled view. Eight studies reported on the type of instruments used [12,17–23]. All surgeons reported using articulated instruments with the exception of Lakdawala et al. [20] and Huang et al. [23]

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Table 2 Operative technical details Author

Single-incision system Device

Adjustable gastric banding Nguyen et al. [11] Multiport Saber et al. [12] Multiport Raman et al. [13] SILSTM Ayloo et al. [14] Multiport Chakravartty et al. Multichanel [15] port Vithiananthan Multiport et al. [16] Gawart et al. [17] Multichanel port Schwack et al. Multiport [18] Sleeve gastrectomy Saber et al. [19] SILSTM Lakdawala et al. SILSTM [20] Park et al. [21] SILSTM Delgado et al. [22] SILSTM/ LESSTM Roux-en-Y gastric bypass Huang et al. [23] Multiport Lee et al. [24] Multiport

Incision

SI ports

Extra incisions

4 (5,5,5,15) or 3 (5,5,15) 3 (5,5,12) 3 (5,5,5) 3 (5,5,15) 4

No or 1 (5) umbilical 1 (5) subxiphoid No Optional (5) subxiphoid No

3 (5,5,15)

Between xiphoid and umbilicus Umbilical Umbilical Supraumbilical

Incision Laparoscope lengh (cm) Tip Diameter (mm)

Instruments Angled vision

3.5-4.5

Flexible 5

—

NA

NA 2.5 5–6

Flexible 5 NA NA NA NA

— NA NA

Articulated NA NA

NA

NA

NA

NA

1 (3) subxiphoid

Between xiphoid NA and umbilicus Left subcostal 5–6

Rigid

NA

45º

NA

NA

1 (2) subxiphoid

NA

NA

Flexible 5

—

Articulated

3 (5,5,12)

Optional (3) subxiphoid

Umbilical

3–4

Rigid

NA

30 º

Articulated

3 (5,5,15) 3 (5,5,12)

No No

Umbilical Umbilical

2.5 2.5

NA Rigid

NA 5

NA 30º

Articulated Straight

3 (5,5,12) 3 (5,5,12)

No 1 (2) subxiphoid

Umbilical Umbilical

2.5 2.5

Flexible 5 Rigid 5

— 30º

Articulated Articulated

3 (5, 12,15) 2 (10,12)

No 1 (5)

Umbilical Umbilical

6 NA

Rigid Rigid

30º 30º

Straight NA

10 10

NA ¼ data not available; SI ¼ single incision. Data in parenthesis represent diameter in mm.

When reported, the skin incision for the insertion of single-port devices initially measured 2.5 cm [13,19–22]. In contrast, a 3–6 cm cutaneous incision was necessary for the multiport technique [11,14,16,18,23]. With the exception of Huang et al. [23] (3.5 cm), none of the studies mentioned the final scar length. The incision was mainly transumbilical [12,13,18–24] or placed between the xiphoid and the umbilicus [11,14,15]. Only Vithiananthan et al. [16] used an incision outside of the midline (left subcostal). In 6 studies no additional trocars were used [13,15,19–21,23]. A subxiphoid trocar (2–5 mm) was routinely placed in 5 studies [12,16,17,22,24] and only when required in 2 [14,18]. Nguyen et al. [11] used an optional 5-mm umbilical trocar. All studies used liver retraction. A retraction device placed through the additional trocar was used in 4 studies [11,22] and was inserted through the single-access point in 4 [14,21]. A percutaneus liver retractor (Nathanson) was used in 5 studies [13–15,16,18,19]. Gawart et al. [17] used a MiniLap device (Mini-Lap Technologies, Stryker, CA, USA). Finally, transparietal sutures were used in some studies [18,19,20,23,24]. Regarding the specific bariatric techniques used, AGBs were performed using a standard pars flaccida technique.

SGs were created at a distance of 4–6 cm from the pylorus over a 32–36F bougie. Oversewing or reinforcement of the staple line was not routinely used [19–22]. Finally, a 15–25 cm3 pouch was created for the RYGB. Huang et al. [23] used a 150–200 cm alimentary limb, whereas Lee et al. [24] preferred a 100-cm limb length. In both studies, a 100-cm biliary limb was created. Surgical characteristics Operative parameters are summarized in Table 3. Conversion to CLBS was reported in 4 studies in the LAGB group, with a global conversion rate of 2.4%, ranging from 0% to 13% [11,15–17]. The conversion rate among all 109 cases of SG was 1.83% and ranged from 0% to 5% [19–21]. There were no conversions among the RYGB patients [23,24]. The use of an additional trocar to finish the procedure was reported in 3 studies of AGB (0%–10%) [15–17], 1 of SG (20%) [22], and 1 of RYGB (20%) [24]. The mean/median estimated blood loss ranged from 8.4 mL to 78 mL (n ¼ 5 studies), slightly higher in the SILBS group, but this difference was only statistically significant in the study by Lee et al. [24]. Interestingly, Saber et al. [19]

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Table 3 Perioperative parameters Author

Operative time (SILBS / CLBS)

Adjustable gastric banding Nguyen et al. 65 / 66 [11] Saber et al. 118 / 78.8 [12] (P ¼ .005) Raman et al. 62.6 / 51,5 [13] (P ¼ .03) Ayloo et al. 78 / 76 [14] Chakravartty 70* / 61.5* et al. [15] Vithiananthan 106.6 / 100.9 et al. [16] Gawart et al. 76.8 / 64.4 [17] (P ¼ .001) Schwack et al. 44.3 / 51.1 [18] (P o .001) Sleeve gastrectomy Saber et al. 128 / 110 [19] (P ¼ .055) Lakdawala 50* / 45* et al. [20] Park et al. [21] 118.4 / 101.1 Delgado et al. 79.2 / 54.1 [22] (P ¼ .002) Roux-en-Y gastric bypass Huang et al. 101.1 / 81.1 [23] (P o .001) Lee et al. [24] 143.7 / 110.1 (P ¼ .000)

Estimated blood loss (mL)

Additional Conversion to Morbidity (%) CLBS (SILBS / CLBS) ports

Reoperation (%) (SILBS / CLBS)

Mortality (%) (SILBS / CLBS)

22 / 2.4

NA

3 (13%)

0/0

0/0

0/0

NA

NA

NA

0/0

0/0

0/0

NA

NA

NA

0/0

0/0

0/0

8.4 / 9

NA

NA

12 / 14

4/0

0/0

NA

4 (9%)

0 (0%)

2.2 / 0

0/0

0/0

NA

1 (10%)

0 (0%)

10 / 5

0/0

0/0

NA

0 (0%)

0 (0%)

0/0

0/0

0/0

NA

NA

NA

6.4 / 5.9

0.9 / 1.5

0.14 / 0

78 / 93

NA

0 (0%)

0/0

0/0

0/0

20* / 28*

NA

0 (0%)

0/0

0/0

0/0

NA NA

NA 4 (20%)

1 1 (5%)

4/0 10 / 4.5

0/0 10 / 4.5

0/0 0/0

NA

NA

NA

5/1

0/0

0/0

0 (0%)

3/2

3/0

0/0

55.6 / 40.3 (P ¼ 20 (20%) .008)

CLBS ¼ conventional laparoscopic bariatric surgery; NA ¼ data not available; SILBS ¼ single-incision laparoscopic bariatric surgery. Data are expressed as mean value, except * median.

and Lakdawala et al. [20] observed a higher estimated blood loss in the conventional laparoscopic SG group. The duration of the surgical procedure was longer in the SILBS group in 12 [12,17,19,24] of the 14 studies analyzed, but only 11 involved significant differences [12,13,17,22–24]. In 2 studies of AGB [11,18] the operative time favored the SILBS technique, resulting in significant differences in the study by Schwack et al. [18]. No major intraoperative complications were observed in these studies. Pain and hospital stay Postoperative pain was assessed using a visual analogue scale in 5 studies [12,14,19–21] (Table 4). In the AGB studies, Saber et al. [12] observed statistically significant differences that favored the SILBS group. In studies on SG, Saber et al. [19] and Lakdawala et al.[20] also observed the same results. However, Park et al. [21] only found better pain results in the SILBS group at 1 hour after the operation, a tendency that was inverted in the following hours.

Consumption of analgesics and duration of analgesic treatment were assessed in 8 studies (Table 4). In all studies [12,13,15,19,20,24] except 2 [21,23] the results favored SILBS, but only 4 of these found significant differences [13,15,20,24]. The mean/median length of hospital stay (LOS) varied from .5 to 4.5 days (n = 11 studies). There was a small variability in the LOS among different types of SILBS, with the exception of the study by Huang et al. [23] in which the mean LOS was notably short (1.12 days). Only Ayloo et al. [14] reported a significantly longer LOS in the CLBS group (Table 3).

Morbidity and reoperations The overall morbidity rate was 5% in the SILBS group and 4.8% in the CLBS group. Table 5 summarizes the number and type of complications in each group. A predominance of minor complications was found among the SILBS cases and minor complications or port complications in the CLBS group.

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Table 4 Postoperative pain, analgesic use, and follow-up Author

Pain (VAS) SILBS / CLBS

Adjustable gastric banding Nguyen et al. [11] NA Saber et al. [12] Postop. 4.8 ⫾ 1.6/5 ⫾ 1.4 Overall 2.5 ⫾ .5/3.5 ⫾ 1.2 (P ¼ 0.012) Raman et al. [13] NA Ayloo et al. [14] At discharge 2.5 / 2.4 Chakravartty et al. [15] NA

Vithiananthan et al. [16] Gawart et al. [17] Schwack et al. [18] Sleeve gastrectomy Saber et al. [19] Lakdawala et al. [20]

Park et al. [21]

Analgesic use SILBS / CLBS

%EWL SILBS / CLBS

Follow-up (mo) SILBS / CLBS

NA

NA

NA

Opiate use (%) 87/100

29 ⫾ 13 / 26 ⫾ 8

5.6 ⫾ 4.4 / 7.8 ⫾ 4.9

8.92 ⫾ 6.97‡/ 9.35 ⫾ 7.87‡

4.2 ⫾ 2.8 / 4.8 ⫾ 3

Opiate use (mg) 33 ⫾ 19.2 / 49 ⫾ 23.78 (P ¼ .01) Analgesic duration (d) 2 ⫾ 3 / 5.7 ⫾ 7.7 (P ¼ .03) NA Opiate use (mg) 10 (0–20)* / 17 (0–90)* (P o .01)

NA

NA

NA 34 (15–116)* / 31 (5–93)* 38 ⫾ 3.8 / 29.6 ⫾ 15.4

NA NA

NA NA

11.2 / 12.5 54.4 ⫾ 16.3 / 46.4 ⫾ 16.1

3/3 24 / 24

4 / 6.5 (P ¼ .003) 4 hr postop. (P 4 .05) 8 hr postop. (P o .05, favors SILBS) 1 hr postop. 3.6 / 5.8 (P ¼ .039) 12 hr postop. 1.2 / .9 24 hr postop. .6 / .3 NA

Opiate use (%) 71.4 / 91.6 Analgesics 24 hr after surgery (%) 6 / 24 (P o .0001)

25.7 / 22.6 52 (39–68)* / 50.8 (27–70)*

2.8 / 1.6 6/6

Opiate dose (mg) 5.6 ⫾ 3 / 6.4 ⫾ 2.6 Analgesic duration (d) 1.8 ⫾ .7 / 1.7 ⫾ .2

37.2 / 39.9

6/6

NA

60.1 / 61.9

6/6

Delgado et al. [22] Roux-en-Y gastric bypass Huang et al. [23] NA Lee et al. [24] NA

NA 12.5 (1–29)* / 14 (5–25)* 12 / 12

Opiate administration 2.4 ⫾ 1.9 / 1.9 ⫾ 1.6 75.4 ⫾ 8.45 / 78.20 ⫾ 10.3 12 / 12 Opiate dose (mg) 62.5 (29.1–142.8)† / NA NA 78.4 (16.8–99.9) )† (P ¼ .021)

CLBS ¼ conventional laparoscopic bariatric surgery; EWL ¼ excess weight loss; NA ¼ data not available; SILBS ¼ single-incision laparoscopic bariatric surgery; VAS ¼ visual analog scale. Data are expressed as mean value, except * median. Data are expressed as mean ⫾ standard deviation, except * median (range) † mean (range) ‡ mean EWL

Two studies of gastric banding registered reoperations in the SILBS group (4% and .9%) [14,18]. Ayloo et al. [14] reported 1 case of a stoma obstruction, and Schwack et al. [18] reported 1 stoma obstruction, 1 omental hemorrhage, 1 small bowel injury, 2 wound complications, and 2 cases of exploratory laparoscopy/laparotomy without significant findings. It is remarkable that in this study [18] the reoperation rates were higher in the CLBS group, although this difference was not statistically significant (Table 3). Delgado et al. [22] performed 2 reoperations (10%) for hemoperitoneum after single-access SG. Finally, in the study by Lee et al. [24] 3 cases of singleaccess RYGB (3%) required reoperation for incomplete pouch division or leakage. Mortality Only in 1 study [18] in the AGB group was perioperative mortality observed (1/739; .14%), at .1% of all cases of

gastric banding and .005% of all SILBS cases. Pulmonary embolism was identified as the cause of death in this patient.

Follow-up, percentage excess weight loss, and comorbidities Mean/median follow-up periods ranged from 3 to 24 months and percentage excess weight loss (%EWL) was highly variable (n ¼ 11 studies) [12,13,15–23]. The %EWL was higher in the SILBS group in 6 studies [12,15,16–20] and higher in the CLBS group in 5 [13,17,21–23]. The high heterogeneity found in these results hinders our ability to detect any tendencies. Finally, only Raman et al. [13] considered the time to return to work (9.54 days in SILBS versus 10.69 days in CLBS), but this difference was not statistically significant.

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Table 5 Postoperative complications Complications Adjustable gastric banding Small bowel injury Stoma obstruction requiring reoperation Exploratory laparoscopy or laparotomy Gastric ulcer Port complications Bleeding omentum Wound infection Wound seroma Minor complications not specified Total Sleeve gastrectomy Pulmonary embolus Hemoperitoneum Total Roux-en-Y gastric bypass Incomplete division of the gastric pouch Leakage Wound seroma Complications not specified Total

SILBS

CLBS

1 2 2 0 1 1 4 1 40 52 (5.6%)

1 4 1 1 13 1 6 0 26 53 (5.9%)

1 2 3 (2.7%)

0 1 1 (1.1%)

1 2 2 0 5 (3.6%)

0 1 0 2 3 (1.5%)

CLBS ¼ conventional laparoscopic bariatric surgery; SILBS ¼ singleincision laparoscopic bariatric surgery.

Resolution of co-morbidities at different follow-up periods were compared in 5 studies [12,16,19,22]. The majority of obesity-related co-morbidities improved or were resolved, with no differences between groups. Cosmetics Cosmetic results were evaluated by Huang et al. [23] and Lee et al. [24] in the 2 studies in the RYGB group. In both studies, patients with SILBS were more satisfied with the scar outcome (P o .05). Cost Ayloo et al. [14] included a cost analysis that favored the CLBS group but without statistically significant differences. Discussion In this systematic review of the medical literature, we have identified and analyzed 13 observational comparative studies and 1 RCT with a total of 2357 patients operated on, comparing the results between SILBS and CLBS. The SILS technique was first described 420 years ago when Pelosi performed supracervical hysterectomies through a single umbilical incision [25]. In the late 1990s the scope of SILS expanded to general surgery. Esposito [26] reported the use of a single-incision technique for appendectomy and Navarra et al. [27] reported the first cholecystectomy in 1997. Later, SILS broadened to more complex surgeries and progressively gained substantial interest among the surgical

community [28,29]. Morbid obesity was initially considered as a detractor to SILS in several procedures. However, with the expansion of this approach, SILS was first included in bariatric surgeries in the year 2008 and early case reports were published. Nguyen et al. [30] described the first cases of AGB, and Saber et al. [31] published the first experiences with single-incision SG. Finally, in 2009, Saber et al. [32] and Huang et al. [33] reported the first single-access RYGB. Patient selection is of paramount importance when performing SILS [34]. Based on our review, super-obesity, previous abdominal surgery, the presence of an incisional hernia, or a xiphoid–umbilicus distance longer than 20 cm could be exclusion criteria for this approach, or at least serve as a warning for technical difficulty, although it is difficult to suggest any recommendation in the case of SILBS. However, some authors do not exclude the latter for SILBS but state that in these cases the incision should be outside the umbilicus [11,14–16]. Regarding surgical devices, instruments, and equipment, SILBS can be performed with commercial single-port devices or with multiple trocars placed through a singleskin incision, but it is difficult to detect any trends of use and it is not possible to make any recommendations in this regard. However, the use of a single-port device would be helpful when a surgical specimen must be extracted. In our review, all the SG procedures were performed using a single-port device [19–22]. Although SILS can be performed with conventional 10mm front-view laparoscopes and straight instruments, crowding over the working area decreases the freedom of motion for the surgeon and assistant. Furthermore, limited triangulation increases the difficulty of tissue exposure and dissection [1]. The use of 5-mm laparoscopes with angledview and articulated instruments improves exposure and manipulation [1,7], a tendency that can be seen in most of the studies selected for this review [11,12,17–20]. Additional ports, retractors, and transparietal sutures were used routinely or when needed in all studies [11,13–24]. In obese patients, one of the biggest surgical difficulties is due to enlarged livers, and retraction continues to present a constant challenge. A wide variety of liver retraction solutions have been proposed, mainly represented by percutaneous devices [13–15,16–19], retractors inserted through the umbilical [14,21] or an additional trocar [11,22], and transparietal sutures [18,19,20,23,24]. The use of the abovementioned resources will provide an improvement in visibility and exposure of the surgical field and assist in adequate tissue management. Finally, regarding the specific bariatric techniques used, all the procedures were performed using standard techniques without significant differences with respect to the conventional laparoscopic approach. Rates of conversion to CLBS were extremely low in AGB (2.4%) and SG (1.8%) groups, with no conversions among RYGB patients. The use of additional trocars could explain these rates. Another possible reason for this is that

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these procedures were performed on selected patients and by experienced laparoscopic bariatric surgeons. Finally, SILBS may be used as a hybrid approach because of the technical difficulties inherent to singleaccess points in obese patients and the amount of assistance needed to perform this surgery. Operative times were longer in almost all SILBS groups of patients [12–17,19–24], with statistical differences in most of them [12,13,17,22–24]. No major intraoperative complications were observed in these studies, and perhaps a limited experience with the SILBS techniques would explain these differences. In this sense the study with the greatest number of patients indicated a significant reduction in SILBS operative times [18] and an improvement of operative times could be expected as experience is gained. All SILBS groups presented relatively low rates of overall morbidity (0%–12%). The global incidence of complications in the overall SILBS group was 4.8%, somewhat lower than the 13% observed in a previous multicenter registry of SILS [7]. We did not observe significant differences between groups in terms of the global incidence of complications [11–24]. Finally, there were no differences in morbidity when complications were summarized by type of surgery, and most of them were minor complications. Morbidity associated with the abdominal wall has also garnered a great deal of interest during the development of SILS. Theoretically, the use of a single incision should be correlated with a lower number of complications. In contrast, many authors defend that a larger incision size, a more severe parietal contusion, and a longer duration of the surgical procedure can be associated with an increase in wound infection and incisional hernia rates [35], as indicated in a recent study of single-incision cholecystectomy [36]. In our review, we observed no differences in the incidence of wound complications. Moreover, no incisional hernias were registered in this systematic review, although the follow-up period in the majority of these studies was short. Regarding reoperations, Delgado et al. [22] performed 2 reoperations (10%) after single-access SG and 1 after using a conventional approach (4.5%) as a result of hemoperitoneum. These rates are higher than those reported in the literature for this complication (2%) [37]. Finally, Lee et al. [24] reported 1 case of incomplete pouch division and 2 cases of leakage (2%), a complication with an incidence that ranges from 0% to 5.6% in large series [38]. Although these studies evaluated initial experiences, reoperations are always of clinical significance and this fact must be considered as a word of caution when evaluating an innovation. In general, the mortality rate of bariatric surgery is low, and in the case of adjustable gastric banding it is remarkably low. The in-hospital mortality rate for this procedure is only .02%, and the risk adjusted mortality index is .4%, compared with .08% and .7%, respectively, for laparoscopic

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RYGB [39]. In our review, although the mortality in the SILBS AGB group was higher (.14%), the cause of death was not associated with the surgical technique. One of the theoretical advantages to reducing the number of incisions is the decrease in postoperative pain and analgesic consumption. The results from this systematic review favor SILBS, although it is remarkable that data are very heterogeneous regarding the time after surgery when the postoperative pain was evaluated and the methods used to analyze analgesic consumption. Length of stay varied among the types of surgery, with an average stay of 24 hours in the majority of AGB cases, o72 hours in the SG group, and close to 5 days in the RYGB group, with no significant differences among groups. Only Ayloo et al. [14] reported a significantly longer LOS in the CLBS group, but they failed to explain the criteria used for discharging patients. Efficacy is a very important issue when evaluating new procedures. The percentage of weight loss among groups indicated small differences, with studies favoring SILBS [12,15,16,18–20] and CLBS [13,17,21–23]. In any case, %EWL was always comparable between groups and the high heterogeneity found could be explained by the differences in the follow-up among studies. Finally, resolution of co-morbidities was comparable among groups when it was taken into account. In our opinion, bariatric techniques performed through SILBS should not be different whether a single-port or a conventional procedure is performed, and for this reason results must be comparable. The cosmetic result can be an important outcome to consider in the bariatric population, where there is a predominance of young women [14], as in our review. In fact, Yeung et al. [40] recently published the results of a survey and visual analog scale scores, which found that patients preferred an umbilical single-incision for hysterectomy. In the 2 studies in which the cosmetic result was evaluated, this aspect was better rated among patients who underwent SILBS [23,24], although these studies evaluated cosmetic result shortly after surgery (1 and 3 months). Besides, in our opinion, bariatric patients have more severe aesthetic problems than the small trocar incisions and it is not uncommon that some of them have to undergo further operations for skin resections. In this context, cosmetic reasons for using a SILBS are not really convincing in this group of patients. Cost is always an important issue when a new technology is evaluated. The initial increases in operative costs related to MIS are mitigated by a reduction in morbidity and LOS. Because SILBS requires access devices and special instruments and equipment, demonstration of any economic benefit over CLBS can be difficult. In our review, only Ayloo et al. [14] included a cost analysis, and the overall direct operative costs were similar between the 2 groups with a difference of only $150, which was not statistically significant. However, if lower morbidity rates, reoperations,

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and LOS are associated with SILBS, it will probably make it this the more cost-effective technique. Our review does involve certain limitations. The fact that the majority of the studies included initial experiences and data from selected patients might be inconvenient when extrapolating these results. There was also only one randomized controlled trial. Meta-analysis was not considered appropriate due to heterogeneity in the bariatric surgical techniques and the limited number of comparative studies, which were mostly observational. Other limitations include the heterogeneity among the different studies in terms of the types of surgical techniques and different access devices, instruments, and equipment used in the SILBS group. Finally, most studies have a follow-up of o1 year, a short period to study the incidence of incisional hernia and to evaluate the %EWL. Given our results, we consider SILBS to be a feasible option in selected patients when performed in a controlled environment of expert bariatric surgeons familiar with the use of reduced access surgery tools. However, there is insufficient evidence to recommend its widespread use compared with CLBS. As in other studies evaluating SILS [33], the available evidence suggests that the primary benefit of this approach could be the cosmetic result, with no clear differences in terms of postoperative pain and LOS. The incidence of complications was small and similar between SILBS and CLBS, although SILBS is associated with prolonged surgical times. Finally, RCTs are needed after the initial period of implementation and learning curve to analyze the safety of these SILBS techniques, the long-term results in weight loss, and the resolution of co-morbidities and their possible benefits.

Disclosures This study was supported by a 2012 grant from Fundacion Mutua Madrileña, Madrid, Spain.

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Editorial comment

Comment on: Single incision laparoscopic bariatric surgery: a systematic review Single port laparoscopic surgery (SPLS) is a rapidly evolving, minimally invasive surgical approach. It offers an attractive blend that combines the familiarity of multiport laparoscopic surgery with the cosmetic appeal of natural orifice translumenal endoscopic surgery. The approach has been applied to a variety of surgical procedures, including appendectomy, cholecystectomy, colectomy, and, more recently, bariatric surgery. The approach is particularly attractive for the placement of an adjustable gastric band, which requires an incision large enough to insert the band and the port, and for the sleeve gastrectomy to allow retrieval of the gastric specimen. However, the true advantage of SPLS over conventional laparoscopic surgery has been a topic of debate. Moreno-Sanz C et al. are to be congratulated for this well-written review of the literature on the use of the single incision laparoscopic approach in bariatric surgery [1]. They present the current literature as several articles have been published since the latest review on the same topic [2]. It highlights the advantages and disadvantages of single incision laparoscopic bariatric surgery (SILBS) without over emphasizing either. However, as this is a new technique, an in-depth description of controversial technical aspects such as access, type of instruments, laparoscope, and liver retraction would have been helpful.

As with any new technique, we should not compromise the outcome for the approach. Efficacy in terms of weight loss and improved co-morbidities should be similar to that of the conventional laparoscopic approach. There is no statistical significant difference in morbidity or mortality between the 2 approaches. However, it must be noted that these published outcomes are mainly from experts in the field. Since our group and others introduced this approach to bariatric surgery, we realize that this approach requires special skills to overcome its associated technical challenges [3–6]. The limitations of the SPLS technique stem from its divergent nature and include lost triangulation, inadequate liver retraction, and instrument conflict. Through the introduction of flexible instruments, the lost triangulation can be adequately restored because the deflecting tips converge onto the target organ. Also, multichannel single ports have helped reduce extracorporeal conflict of instruments, thus providing a wider range of motion without sacrificing the pneumoperitoneum. Morbid obesity initially was considered a contraindication, but soon it became an indication for the SPLS approach. We have found that to be particularly useful for a selected group of patients, especially women with a short distance between the xiphoid process and umbilicus. We do not compromise the outcome for this technique, so we do not hesitate to add