REVIEW ARTICLE ANZJSurg.com
Single-incision laparoscopic hernioplasty versus multi-incision laparoscopic hernioplasty: a meta-analysis Hao Lai,*1 Guojian Li,† Jun Xiao,*1 Yuan Lin* and Bangyu Lu‡ *Department of Gastrointestinal Surgery, Tumor Hospital of Guangxi Medical University, Nanning, Guangxi Autonomous Region, China †Administrative Department, Provincial Departments of Health, Nanning, Guangxi Autonomous Region, China and ‡Department of Minimally Invasive Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Autonomous Region, China
Key words hernioplasty, inguinal hernia, laparoscopy, meta-analysis, SILH. Correspondence Professor Yuan Lin, Department of Gastrointestinal Surgery, Tumor Hospital of Guangxi Medical University, 22 Shuangyong Road, Nanning 530021, Guangxi Autonomous Region, China. Email: [email protected] H. Lai MD; G. J. Li MD; J. Xiao MD; Y. Lin MD; B. Y. Lu MM. 1
These authors contributed equally to this work and should be considered as co-first authors. Accepted for publication 1 September 2013. doi: 10.1111/ans.12407
Abstract Background: Laparoscopic hernioplasty is the gold standard treatment for inguinal hernias. Recently, single-incision laparoscopic hernioplasty (SILH) has been suggested as an alternative technique. It is not evident whether the benefits of this procedure overcome the potential increased risk. Objective: The aim of this study was to compare the outcomes of SILH with conventional multi-incision laparoscopic hernioplasty (MILH) using a meta-analysis of available controlled clinical trials. Methods: Eligible articles were identified by searching several databases including Embase, Cochrane, PubMed and Google Scholar databases, up until May 2013. Evaluated outcomes were operative time, post-operative hospital stay, complications, conversion and recurrence. Results: Eight controlled clinical trials on 926 patients were randomized to either SILH (495 patients) or MILH (431 patients) for meta-analysis. Overall, there was no significant difference between SILH and MILH in complications, operative time for bilateral inguinal hernia repair, hospital stay, short-term recurrence or conversions. However, the operative time for unilateral inguinal hernia repair was significantly longer for SILH than for MILH (standardized mean difference 0.23 (95% confidence interval: 0.09–0.38); P = 0.00, I2 = 73.6%). Conclusions: Our meta-analysis showed that SILH is feasible and safe in certain patients when compared to MILH, and carries a similar outcome, with the exception of longer operative times for unilateral inguinal hernia repair. Additional high-powered randomized trials are needed to determine whether SILH truly offers any advantages; these future studies should focus particularly on failure of technique, pain score, analgesia requirements, cosmesis and quality of life.
Introduction Laparoscopic hernioplasty is largely accepted as the standard treatment for inguinal hernias due to its several advantages compared with open hernioplasty, such as a smaller incision, less postoperative pain, faster recovery and similar recurrence rate,1–3 even in complicated conditions.4 Despite its success, the disadvantage of this procedure is that multiple incisions are needed. Following the laparoscopic revolution of the 1980s, minimally invasive surgery has continued to evolve, with the introduction of so-called single-incision laparoscopic surgery (SILS), which can reduce ANZ J Surg 84 (2014) 128–136
the invasiveness of surgical procedures, including hernioplasty. To date, many studies have described single-incision laparoscopic hernioplasty (SILH) in adults and children, but most were not controlled clinical trials (CCTs) and failed to demonstrate major differences in clinical results between the single-incision laparoscopic technique and standard multiport laparoscopy. Additionally, the safety of SILH is not well established. The aim of this systematic review was to examine currently available evidence on the feasibility and safety of SILH and to compare short-term outcomes after SILH and multi-incision laparoscopic hernioplasty (MILH) as reported in CCTs. © 2013 Royal Australasian College of Surgeons
SILH versus MILH
Materials and methods Literature search A systematic literature search was performed using Embase, Cochrane, PubMed and Google Scholar databases to search for studies comparing SILH to MILH (to May 2013). The following medical subject heading (MeSH) terms and words were used for the search, in all possible combinations: ‘laparoendoscopic single site’, ‘LSS’, ‘single port access’, ‘SPA’, ‘single port surgery’, ‘SPS’, ‘transumbilical endoscopic surgery (TUES)’, ‘laparoendoscopic single site surgery’, ‘single incision laparoscopic surgery’, ‘SILS’, ‘transumbilical single port’, ‘TUSP’, ‘single incision multiport’, ‘inguinal herniorrhaphy’, ‘inguinal hernia repair’ and ‘inguinal hernioplasty’. A filter for identifying CCTs recommended by the Cochrane Collaboration5 was used to exclude non-randomized studies in MEDLINE and Embase.6 A second-level search that included a manual search of the reference lists of the retrieved articles helped to identify potential eligible studies.
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was performed using the odds ratio (OR) and a random-effects model or a fixed-effects model according to the presence or absence of heterogeneity. Statistical analysis for continuous variables was performed using the standardized mean difference. We used the Q-based chi-square test and the I2 statistic to assess heterogeneity between studies, with a P-value of less than 0.10 representing statistical significance. Sensitivity and subgroup analyses were used to explore potential causes of heterogeneity. Subgroup analyses were performed according to the types of operation being compared: single-incision laparoscopic total extraperitoneal (SILTEP) hernioplasty versus multi-incision laparoscopic total extraperitoneal (MILTEP) hernioplasty, single-incision laparoscopic percutaneous extraperitoneal closure (SILPEC) versus multi-incision laparoscopic percutaneous extraperitoneal closure, single-incision laparoscopic trans-abdominal pre-peritoneal (SILTAP) herniorrhaphy versus MILTEP, and SILTAP versus multi-incision laparoscopic transabdominal pre-peritoneal herniorrhaphy.
Inclusion and exclusion criteria
Results
This meta-analysis included only CCTs that compared SILH to MILH. SILH can be performed using laparoscopic or endoscopic instruments, in which case it is referred to as laparoendoscopic single-site surgery or single-incision endoscopic surgery. All included studies had to report at least one of the following outcome measures: post-operative pain score, analgesia requirements, complications, conversion rate, operative time, post-operative hospital stay, recurrence rate and cosmetic score. Reviews, case reports, retrospective analyses and quasi-randomized trials were excluded. For duplicate publications, the smaller data set was excluded.
Of 681 records retrieved from the database search, none was identified through other sources. Figure 1 depicts a PRISMA flow chart for study inclusion and exclusion. After removing duplicate results, 643 records remained. Of these, comparisons of SILH and MILH were considered suitable for the pooled analysis. Three articles might have qualified for pooled analysis but were excluded because no full text was available.9–11 We attempted to communicate with the corresponding author to obtain the full text but no e-mail or telephone number was available.
Outcome measures Outcome variables were considered suitable for analysis if they met the following criteria: (i) continuous outcomes were reported as means and standard deviations, and (ii) identical variables reported by a minimum of two studies. Five outcome variables were considered the most suitable for analysis: operative time (min), post-operative hospital stay (day), complications (n), conversion (n) and recurrence (n). If the units used for the end point were not uniform, we attempted to convert them for ease of analysis. For example, for length of hospital stay, one study used minutes as the measurement7 and one used days,8 so we converted minutes to days for uniformity.
Characteristics of included studies The characteristics of included studies are summarized in Table 1. In total, 926 patients were randomized to either SILH (495 patients) or MILH (431 patients). The articles included in the quantitative synthesis were published between 2008 and 2013. No language
Data extraction and assessment of the risk of bias Data were extracted from each study by two independent reviewers (Hao Lai and Jun Xiao); the risk of bias was also evaluated by the reviewers using the Cochrane Handbook for Systematic Reviews of Interventions.5 The assessment was based on sequence generation, allocation concealment, blinding, incomplete outcome data, selective outcome reporting and other sources of bias. Agreement was achieved through discussion when necessary.
Statistical analysis Data were analysed using the software Stata 9.0 (Stata Corp, College Station, TX, USA). Statistical analysis for dichotomous variables © 2013 Royal Australasian College of Surgeons
Fig. 1. Flow chart for the systematic search and study selection strategy.
CCT
CCT
CCT CCT
SILTEP versus MILTEP Rui et al.15
Sherwinter7
Tai et al.8 Cugura et al.12
2010–2011
2009 2008–2009
2009–2010
2009–2010
South Korea
South Korea Croatia
USA
China
Japan
Japan
India Japan
Country
Adults
Adults Adults
Adults
Adults
Adults
Adults
Children Children
Patients
76
54 22
52
20
35
35
112 60
SILH
n
93
85 22
52
25
20
30
51 117
MILH
A glove single port device
Single-port system or 3 ports through a single incision Homemade single port 3 ports through a single incision
Single-port system
EZ access port
EZ access port
5-mm subumbilical port 4-mm port
SILH device
3 ports
3 ports 3 ports
3 ports
3 ports
3 ports
3 ports
3 ports 3 ports
MILH device
31/45/NA
5/6/43 7/8/7
18/25/9
NA
15/14/6
15/14/6
31/70/11 NA
SILH
36/57/NA
6/12/67 10/9/3
14/25/13
NA
6/12/2
11/19/0
11/34/6 NA
MILH
Sight (L/R/bilateral)
NA Obstructed and strangulated hernias, inguinoscrotal hernias, patients with associated other hernias, such as ventral hernias Age ≤ 20 years old; recurrent hernia; cardiopulmonary disfunction; emergency operation for treatment of acute bowel incarceration
Hypogastric zone operation history; incarcerated hernia; irreducible hernia; recurrent inguinal hernia; coagulation disorder glucocorticoid user; immunosuppressor user; anti-tumour drug user; lost follow-up patients NA
Patients with previous lower abdominal and pelvic surgery·
Patients with previous lower abdominal and pelvic surgery
NA NA
Exclusion criteria
CCT, controlled clinical trial; L, left; MILH, multi-incision laparoscopic hernioplasty; MILPEC, multi-incision laparoscopic percutaneous extraperitoneal closure; MILTAP, multi-incision laparoscopic trans-abdominal pre-peritoneal; MILTEP, multi-incision laparoscopic total extraperitoneal; NA, not available; R, right; SILH, single-incision laparoscopic hernioplasty; SILPEC, single-incision laparoscopic percutaneous extraperitoneal closure; SILTAP, single-incision laparoscopic trans-abdominal pre-peritoneal; SILTEP, single-incision laparoscopic total extraperitoneal.
CCT
CCT
SILTAP versus MILTAP Sato et al.17 (group 2)
Kim et al.16
2007–2011
CCT
2007–2011
2006–2007 2009–2010
Study period
CCT CCT
Study design
SILPEC versus MILPEC Bharathi et al.14 Uchida et al.13 SILTAP versus MILTEP Sato et al.17 (group 1)
Study
Table 1 Characteristics of included studies
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SILH versus MILH
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Table 2 Follow-up time and mesh fixation Study
Duration of follow-up SILH
Type of mesh used (SILH and MILH)
MILH
Mesh fixation technique (SILH and MILH)
SILPEC versus MILPEC Bharathi et al.14 Uchida et al.13 SILTAP versus MILTEP Sato et al.17 (group 1)
3M 1.4 ± 1.2 M
3M 6.5 ± 1.8 M
NA NA
NA NA
NA
NA
A 11 cm × 15 cm piece of polypropylene mesh
Applying titanium spiral tacks (ProTack)
SILTAP versus MILTAP Sato et al.17 (group 2)
NA
NA
A 11 cm × 15 cm piece of polypropylene mesh
Applying titanium spiral tacks (ProTack)
SILTEP versus MILTEP Rui et al.15 Sherwinter7
3.8 (2.0∼5.5) M 1M
3.8 (2.0∼5.5) M 1M
A polypropylene mesh A parietex anatomical mesh
Tai et al.8 Cugura et al.12
8.7 M 11.5 ± 2.5 M
11 M 11 ± 1.6 M
A piece of polypropylene mesh Two pieces measuring 11 × 15 and 4 × 15 cm polypropylene mesh
Kim et al.16
10 D
10 D
A 13 × 9 cm parietex mesh
NA Applying titanium spiral tacks (ProTack) Applying two tacks Mesh was not fixed in the first few cases of SILH patients. But fixation was applying in the rest of SILH patients and performed in the same way as MILH. Applying two tacks (type unknown)
D, day; M, month; MILH, multi-incision laparoscopic hernioplasty; MILPEC, multi-incision laparoscopic percutaneous extraperitoneal closure; MILTAP, multi-incision laparoscopic trans-abdominal pre-peritoneal; MILTEP, multi-incision laparoscopic total extraperitoneal; NA, not available; SILH, single-incision laparoscopic hernioplasty; SILPEC, single-incision laparoscopic percutaneous extraperitoneal closure; SILTAP, single-incision laparoscopic trans-abdominal pre-peritoneal; SILTEP, single-incision laparoscopic total extraperitoneal.
restriction was placed on the search; seven included trials were reported in English and one was reported in Chinese.7,8,12–17 One study was conducted in China,15 two in Japan,13,17 one in Croatia,12 one in the USA,7 one in India14 and two in South Korea.8,16 One study included three group dates and was divided into two groups of comparative dates to allow pooled analysis of the outcomes.17 Two of the records were children who underwent SILPEC,13,14 and six were adults who underwent SILTEP or SILTAP.7,8,12,15–17 Of the four studies that described the exclusion criteria for patients, the most common reason for exclusion was a history of a hypogastric zone operation.12,15–17 All MILH devices were three-port systems, while the SILH devices were of various types. In most of the included studies, the follow-up was less than 12 months (Table 2), meaning that all outcomes – such as complications and recurrence rates – were classified as short-term outcomes. The type of mesh used for the adults in six studies differed (Table 2). Most studies favoured polypropylene mesh,8,12,15,17 while others used parietex anatomical mesh.7,16 In five studies,7,8,12,16,17 the mesh was fixed by applying titanium spiral tacks, while in one study the mesh fixation technique was unclear15 (Table 2). In an identical study, the mesh used and the mesh fixation technique in SILH were exactly as in MILH. Cosmetic outcome was evaluated in only two studies8,14 and in one of them this outcome was not reported as means and standard deviation,14 pain score and analgesia requirements were evaluated in only one study,7,8 leading us to exclude these outcomes from our meta-analysis.
Outcome measurements Complications included hematoma/seroma, peritoneal injury, extensive subcutaneous emphysema, urinary retention, vascular injury, hydrocele, decreased testicular size, wound erythema, wound infection, umbilical hernia and ileus. Subgroup analysis showed no © 2013 Royal Australasian College of Surgeons
significant difference in complications between any comparative subgroup. In the pooled analysis, there was no significant difference in total complications between SILH and MILH, and no significant heterogeneity was observed (Fig. 2a, Table 3). Six studies described the length of hospital stay.7,8,12,15–17 Subgroup analysis showed that hospital stay was not significantly different in any comparative subgroup except SILTAP versus MILTEP, and overall pool estimates showed that there were no significant differences in hospital stay between SILH and MILH. Low heterogeneity was seen across trials (Fig. 2b, Table 4) and no publication bias was absent (P = 0.06). Operative time for unilateral inguinal hernia repair was reported by eight studies,7,8,12–17 but in one of them this outcome was not reported as means and standard deviation and was excluded.14 Subgroup analysis showed that the average operative time for SILPEC and SILTAP for unilateral inguinal hernia repair did not differ significantly compared to conventional technology. Conversely, the pooled estimate in operative time from five CCTs in the SILTEP versus MILTEP subgroup suggested a significant difference. Overall, the pooled estimate of operative time suggested that SILH takes longer than MILH for unilateral inguinal hernia repair, with evidence of significant heterogeneity (Fig. 3a, Table 5), but without publication bias (P = 0.85). Six studies reported operative times for bilateral inguinal hernia repair,7,8,12–14,17 but in one of them this outcome was not reported as means and standard deviation.14 Subgroup analysis showed no significant difference for unilateral inguinal hernia repair between SILH and MILH for each group. Overall estimates also showed that there was no significant difference between SILH and MILH, without evidence of significant heterogeneity (Fig. 3b, Table 6) and without publication bias (P = 0.26).
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Lai et al.
(a)
Odds ratio (95% Cl)
Study SILPEC versus MILPEC Bharathi et al.14 Subtotal
(b) % Weight
Standardized mean difference (95% Cl) % Weight
Study SILTAP versus MILTAP
0.80 (0.26, 2.53) 20.9 0.80 (0.26, 2.53) 20.9
SILTAP versus MILTAP Sato et al.17 Subtotal
1.19 (0.10, 13.99) 1.19 (0.10, 13.99)
3.9 3.9
Sato et al.17 Subtotal
4.69 (0.22, 101.72) 1.6 4.69 (0.22, 101.72) 1.6
SILTEP versus MILTEP Rui et al.15 Sherwinter7 Tai et al.8 Kim et al.16 Subtotal
1.28 (0.16, 9.97) 5.3 1.23 (0.35, 4.30) 14.6 0.54 (0.16, 1.79) 26.2 0.71 (0.25, 2.06) 27.4 0.79 (0.42, 1.49) 73.5
Overall
0.87 (0.52, 1.47) 100.0
.009830
1 Odds ratio
101.720
8.4 8.4
0.57 (0.08, 1.07)
10.3
0.57 (0.08, 1.07)
10.3
SILTAP versus MILTEP Sato et al.17 Subtotal
SILTAP versus MILTEP Sato et al.17 Subtotal
0.18 (–0.37, 0.73) 0.18 (–0.37, 0.73)
Fig. 2. (a) Forest plots of complications in subgroup analysis by ethnicity using a fix-effect model (contrast SILH versus MILH). (b) Forest plots of hospital stay in subgroup analysis by ethnicity using a fix-effect model (contrast SILH versus MILH).
SILTEP versus MILTEP Rui et al.15
0.53 (–0.07, 1.13)
Sherwinter7
0.00 (–0.38, 0.38)
17.3
Tai et al.8
0.00 (–0.34, 0.34)
21.9
Cugura et al.12
0.00 (–0.59, 0.59)
Kim et al.16
7.1
7.3
–0.21 (–0.51, 0.09)
27.6
Subtotal
–0.02 (–0.20, 0.15)
81.3
Overall
0.05 (–0.11, 0.21)
100.0
–1.1279
0 Standardized mean difference
1.12798
Table 3 Subgroup analysis comparing SILH and MILH for complications 3
Pooled OR
P
Subgroup SILPEC versus MILPEC SILTAP versus MILTAP SILTAP versus MILTEP SILTEP versus MILTEP Overall
0.80 (0.26, 2.53) 1.19 (0.10, 13.99) 4.69 (0.22, 101.72) 0.79 (0.42, 1.49) 0.87 (0.52, 1.47)
0.71 0.89 0.33 0.47 0.61
Test for heterogeneity X2
P
— — — 0% 0%
— — — 0.77 0.88
MILH, multi-incision laparoscopic hernioplasty; MILPEC, multi-incision laparoscopic percutaneous extraperitoneal closure; MILTAP, multi-incision laparoscopic trans-abdominal pre-peritoneal; MILTEP, multi-incision laparoscopic total extraperitoneal; OR, odds ratio; SILH, single-incision laparoscopic hernioplasty; SILPEC, single-incision laparoscopic percutaneous extraperitoneal closure; SILTAP, single-incision laparoscopic trans-abdominal pre-peritoneal; SILTEP, single-incision laparoscopic total extraperitoneal.
Table 4 Subgroup analysis comparing SILH and MILH for hospital stay 4
Pooled SMD
P
Subgroup SILTAP versus MILTAP SILTAP versus MILTEP SILTEP versus MILTEP Overall
0.17 (−0.37, 2.53) 0.57 (0.37, 1.07) −0.03 (−0.20, 0.15) 0.05 (−0.11,0.21)
0.53 0.02 0.79 0.51
Test for heterogeneity X2
P
— — 15.8% 39.3%
— — 0.31 0.13
MILH, multi-incision laparoscopic hernioplasty; MILTAP, multi-incision laparoscopic trans-abdominal pre-peritoneal; MILTEP, multi-incision laparoscopic total extraperitoneal; SILH, single-incision laparoscopic hernioplasty; SILTAP, single-incision laparoscopic trans-abdominal pre-peritoneal; SILTEP, single-incision laparoscopic total extraperitoneal; SMD, standardized mean difference.
Six studies evaluated conversions,7,8,14–17 but only three patients from two studies required conversions.14,17 Conversions were the same in both treatment subgroups, and the overall estimates also showed no significant difference between SILH and MILH, without heterogeneity across trials (Fig. 4a, Table 7), and no publication bias (P = 0.09). Short-term recurrence was evaluated by seven studies,7,8,12–15,17 but present in only three of them.12,14,17 No difference in short-term recurrence was found, and the overall pool estimate continued to show this trend, without heterogeneity across trials (Fig. 4b, Table 8), and without publication bias (P = 0.89).
Sensitivity analysis The inclusion criteria of this meta-analysis were subjected to sensitivity analysis to determine whether modification of the inclusion criteria of the meta-analysis affected the results (Fig. 5a). A single study involved in the meta-analysis was deleted each time to reflect
the influence of each individual data set on the pooled ORs. The corresponding pooled ORs were essentially unaltered (data not shown), indicating that our results were statistically sound.
Risk of publication bias A funnel plot of the studies included in our primary outcome of complications was created to explore publication bias (Fig. 5b). The funnel plot shows the confidence interval (CI) and effect estimate. The latter shows a symmetrical distribution around the effect estimate, indicating that publication bias was likely minimal for studies that evaluated SILH techniques. Although complications were evaluated by eight studies,7,8,12–17 two studies did not have any event in either group and so were not included in the funnel plot.12,13 The funnel plot should be interpreted with caution. Linear regression analysis was not performed to determine funnel plot asymmetry as none of the dichotomous outcomes were included in sufficient trials for this method. © 2013 Royal Australasian College of Surgeons
SILH versus MILH
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Fig. 3. (a) Forest plots of operative time for unilateral inguinal hernia repair in subgroup analysis by ethnicity using a fix-effect model (contrast SILH versus MILH). (b) Forest plots of operative time for bilateral inguinal hernia repair in subgroup analysis by ethnicity using a fix-effect model (contrast SILH versus MILH).
(a)
(b) Standardized mean difference (95% Cl) % Weight
Study SILPEC versus MILPEC Uchida et al.13 Subtotal
–0.08 (–0.39, 0.23) –0.08 (–0.39, 0.23)
21.2 21.2
SILTAP versus MILTAP Sato et al.17 Subtotal
0.16 (–0.39, 0.71) 0.16 (–0.39, 0.71)
6.8 6.8
SILTAP versus MILTEP Sato et al.17 Subtotal
–0.10 (–0.58, 0.39) –0.10 (–0.58, 0.39)
8.6 8.6
SILPEC versus MILPEC Uchida et al.13 Subtotal
0.06 (–0.26, 0.37)
32.5
0.06 (–0.26, 0.37)
32.5
–0.24 (–0.79, 0.31)
10.4
–0.24 (–0.79, 0.31)
10.4
SILTAP versus MILTAP Sato et al.17 Subtotal
SILTEP versus MILTEP
SILTEP versus MILTEP Rui et al.15 Sherwinter7 Tai et al.8 Cugura et al.12 Kim et al.16 Subtotal Overall
–1.5733
Standardized mean difference (95% Cl) % Weight
Study
0 Standardized mean difference
0.95 (0.33, 1.57) 0.27 (–0.12, 0.65) 0.78 (0.42, 1.13) –0.55 (–1.15, 0.06) 0.29 (–0.02, 0.59) 0.39 (0.21, 0.57)
5.3 13.8 16.5 5.7 22.1 63.4
0.23 (0.09, 0.38)
100.0
1.57335
Sherwinter7
–0.01 (–0.39, 0.38)
21.3
Tai et al.8
0.24 (–0.10, 0.58)
26.9
Cugura et al.12
0.00 (–0.59, 0.59)
9.0
Subtotal
0.11 (–0.12, 0.34)
57.2
Overall
0.06 (–0.12, 0.23)
100.0
–.79241
0 Standardized mean difference
.792419
Table 5 Subgroup analysis according to operation time for unilateral inguinal hernia repair in comparison of SILH and MILH 5
Pooled SMD
P
Subgroup SILPEC versus MILPEC SILTAP versus MILTAP SILTAP versus MILTEP SILTEP versus MILTEP Overall
−0.08 (−0.39, 0.23) 0.16 (−0.39, 0.71) −0.10 (−0.58, 0.39) 0.39 (0.21, 0.57) 0.23 (0.09, 0.38)
0.60 0.57 0.70
Single-incision laparoscopic hernioplasty versus multi-incision laparoscopic hernioplasty: a meta-analysis Hao Lai,*1 Guojian Li,† Jun Xiao,*1 Yuan Lin* and Bangyu Lu‡ *Department of Gastrointestinal Surgery, Tumor Hospital of Guangxi Medical University, Nanning, Guangxi Autonomous Region, China †Administrative Department, Provincial Departments of Health, Nanning, Guangxi Autonomous Region, China and ‡Department of Minimally Invasive Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Autonomous Region, China
Key words hernioplasty, inguinal hernia, laparoscopy, meta-analysis, SILH. Correspondence Professor Yuan Lin, Department of Gastrointestinal Surgery, Tumor Hospital of Guangxi Medical University, 22 Shuangyong Road, Nanning 530021, Guangxi Autonomous Region, China. Email: [email protected] H. Lai MD; G. J. Li MD; J. Xiao MD; Y. Lin MD; B. Y. Lu MM. 1
These authors contributed equally to this work and should be considered as co-first authors. Accepted for publication 1 September 2013. doi: 10.1111/ans.12407
Abstract Background: Laparoscopic hernioplasty is the gold standard treatment for inguinal hernias. Recently, single-incision laparoscopic hernioplasty (SILH) has been suggested as an alternative technique. It is not evident whether the benefits of this procedure overcome the potential increased risk. Objective: The aim of this study was to compare the outcomes of SILH with conventional multi-incision laparoscopic hernioplasty (MILH) using a meta-analysis of available controlled clinical trials. Methods: Eligible articles were identified by searching several databases including Embase, Cochrane, PubMed and Google Scholar databases, up until May 2013. Evaluated outcomes were operative time, post-operative hospital stay, complications, conversion and recurrence. Results: Eight controlled clinical trials on 926 patients were randomized to either SILH (495 patients) or MILH (431 patients) for meta-analysis. Overall, there was no significant difference between SILH and MILH in complications, operative time for bilateral inguinal hernia repair, hospital stay, short-term recurrence or conversions. However, the operative time for unilateral inguinal hernia repair was significantly longer for SILH than for MILH (standardized mean difference 0.23 (95% confidence interval: 0.09–0.38); P = 0.00, I2 = 73.6%). Conclusions: Our meta-analysis showed that SILH is feasible and safe in certain patients when compared to MILH, and carries a similar outcome, with the exception of longer operative times for unilateral inguinal hernia repair. Additional high-powered randomized trials are needed to determine whether SILH truly offers any advantages; these future studies should focus particularly on failure of technique, pain score, analgesia requirements, cosmesis and quality of life.
Introduction Laparoscopic hernioplasty is largely accepted as the standard treatment for inguinal hernias due to its several advantages compared with open hernioplasty, such as a smaller incision, less postoperative pain, faster recovery and similar recurrence rate,1–3 even in complicated conditions.4 Despite its success, the disadvantage of this procedure is that multiple incisions are needed. Following the laparoscopic revolution of the 1980s, minimally invasive surgery has continued to evolve, with the introduction of so-called single-incision laparoscopic surgery (SILS), which can reduce ANZ J Surg 84 (2014) 128–136
the invasiveness of surgical procedures, including hernioplasty. To date, many studies have described single-incision laparoscopic hernioplasty (SILH) in adults and children, but most were not controlled clinical trials (CCTs) and failed to demonstrate major differences in clinical results between the single-incision laparoscopic technique and standard multiport laparoscopy. Additionally, the safety of SILH is not well established. The aim of this systematic review was to examine currently available evidence on the feasibility and safety of SILH and to compare short-term outcomes after SILH and multi-incision laparoscopic hernioplasty (MILH) as reported in CCTs. © 2013 Royal Australasian College of Surgeons
SILH versus MILH
Materials and methods Literature search A systematic literature search was performed using Embase, Cochrane, PubMed and Google Scholar databases to search for studies comparing SILH to MILH (to May 2013). The following medical subject heading (MeSH) terms and words were used for the search, in all possible combinations: ‘laparoendoscopic single site’, ‘LSS’, ‘single port access’, ‘SPA’, ‘single port surgery’, ‘SPS’, ‘transumbilical endoscopic surgery (TUES)’, ‘laparoendoscopic single site surgery’, ‘single incision laparoscopic surgery’, ‘SILS’, ‘transumbilical single port’, ‘TUSP’, ‘single incision multiport’, ‘inguinal herniorrhaphy’, ‘inguinal hernia repair’ and ‘inguinal hernioplasty’. A filter for identifying CCTs recommended by the Cochrane Collaboration5 was used to exclude non-randomized studies in MEDLINE and Embase.6 A second-level search that included a manual search of the reference lists of the retrieved articles helped to identify potential eligible studies.
129
was performed using the odds ratio (OR) and a random-effects model or a fixed-effects model according to the presence or absence of heterogeneity. Statistical analysis for continuous variables was performed using the standardized mean difference. We used the Q-based chi-square test and the I2 statistic to assess heterogeneity between studies, with a P-value of less than 0.10 representing statistical significance. Sensitivity and subgroup analyses were used to explore potential causes of heterogeneity. Subgroup analyses were performed according to the types of operation being compared: single-incision laparoscopic total extraperitoneal (SILTEP) hernioplasty versus multi-incision laparoscopic total extraperitoneal (MILTEP) hernioplasty, single-incision laparoscopic percutaneous extraperitoneal closure (SILPEC) versus multi-incision laparoscopic percutaneous extraperitoneal closure, single-incision laparoscopic trans-abdominal pre-peritoneal (SILTAP) herniorrhaphy versus MILTEP, and SILTAP versus multi-incision laparoscopic transabdominal pre-peritoneal herniorrhaphy.
Inclusion and exclusion criteria
Results
This meta-analysis included only CCTs that compared SILH to MILH. SILH can be performed using laparoscopic or endoscopic instruments, in which case it is referred to as laparoendoscopic single-site surgery or single-incision endoscopic surgery. All included studies had to report at least one of the following outcome measures: post-operative pain score, analgesia requirements, complications, conversion rate, operative time, post-operative hospital stay, recurrence rate and cosmetic score. Reviews, case reports, retrospective analyses and quasi-randomized trials were excluded. For duplicate publications, the smaller data set was excluded.
Of 681 records retrieved from the database search, none was identified through other sources. Figure 1 depicts a PRISMA flow chart for study inclusion and exclusion. After removing duplicate results, 643 records remained. Of these, comparisons of SILH and MILH were considered suitable for the pooled analysis. Three articles might have qualified for pooled analysis but were excluded because no full text was available.9–11 We attempted to communicate with the corresponding author to obtain the full text but no e-mail or telephone number was available.
Outcome measures Outcome variables were considered suitable for analysis if they met the following criteria: (i) continuous outcomes were reported as means and standard deviations, and (ii) identical variables reported by a minimum of two studies. Five outcome variables were considered the most suitable for analysis: operative time (min), post-operative hospital stay (day), complications (n), conversion (n) and recurrence (n). If the units used for the end point were not uniform, we attempted to convert them for ease of analysis. For example, for length of hospital stay, one study used minutes as the measurement7 and one used days,8 so we converted minutes to days for uniformity.
Characteristics of included studies The characteristics of included studies are summarized in Table 1. In total, 926 patients were randomized to either SILH (495 patients) or MILH (431 patients). The articles included in the quantitative synthesis were published between 2008 and 2013. No language
Data extraction and assessment of the risk of bias Data were extracted from each study by two independent reviewers (Hao Lai and Jun Xiao); the risk of bias was also evaluated by the reviewers using the Cochrane Handbook for Systematic Reviews of Interventions.5 The assessment was based on sequence generation, allocation concealment, blinding, incomplete outcome data, selective outcome reporting and other sources of bias. Agreement was achieved through discussion when necessary.
Statistical analysis Data were analysed using the software Stata 9.0 (Stata Corp, College Station, TX, USA). Statistical analysis for dichotomous variables © 2013 Royal Australasian College of Surgeons
Fig. 1. Flow chart for the systematic search and study selection strategy.
CCT
CCT
CCT CCT
SILTEP versus MILTEP Rui et al.15
Sherwinter7
Tai et al.8 Cugura et al.12
2010–2011
2009 2008–2009
2009–2010
2009–2010
South Korea
South Korea Croatia
USA
China
Japan
Japan
India Japan
Country
Adults
Adults Adults
Adults
Adults
Adults
Adults
Children Children
Patients
76
54 22
52
20
35
35
112 60
SILH
n
93
85 22
52
25
20
30
51 117
MILH
A glove single port device
Single-port system or 3 ports through a single incision Homemade single port 3 ports through a single incision
Single-port system
EZ access port
EZ access port
5-mm subumbilical port 4-mm port
SILH device
3 ports
3 ports 3 ports
3 ports
3 ports
3 ports
3 ports
3 ports 3 ports
MILH device
31/45/NA
5/6/43 7/8/7
18/25/9
NA
15/14/6
15/14/6
31/70/11 NA
SILH
36/57/NA
6/12/67 10/9/3
14/25/13
NA
6/12/2
11/19/0
11/34/6 NA
MILH
Sight (L/R/bilateral)
NA Obstructed and strangulated hernias, inguinoscrotal hernias, patients with associated other hernias, such as ventral hernias Age ≤ 20 years old; recurrent hernia; cardiopulmonary disfunction; emergency operation for treatment of acute bowel incarceration
Hypogastric zone operation history; incarcerated hernia; irreducible hernia; recurrent inguinal hernia; coagulation disorder glucocorticoid user; immunosuppressor user; anti-tumour drug user; lost follow-up patients NA
Patients with previous lower abdominal and pelvic surgery·
Patients with previous lower abdominal and pelvic surgery
NA NA
Exclusion criteria
CCT, controlled clinical trial; L, left; MILH, multi-incision laparoscopic hernioplasty; MILPEC, multi-incision laparoscopic percutaneous extraperitoneal closure; MILTAP, multi-incision laparoscopic trans-abdominal pre-peritoneal; MILTEP, multi-incision laparoscopic total extraperitoneal; NA, not available; R, right; SILH, single-incision laparoscopic hernioplasty; SILPEC, single-incision laparoscopic percutaneous extraperitoneal closure; SILTAP, single-incision laparoscopic trans-abdominal pre-peritoneal; SILTEP, single-incision laparoscopic total extraperitoneal.
CCT
CCT
SILTAP versus MILTAP Sato et al.17 (group 2)
Kim et al.16
2007–2011
CCT
2007–2011
2006–2007 2009–2010
Study period
CCT CCT
Study design
SILPEC versus MILPEC Bharathi et al.14 Uchida et al.13 SILTAP versus MILTEP Sato et al.17 (group 1)
Study
Table 1 Characteristics of included studies
130 Lai et al.
© 2013 Royal Australasian College of Surgeons
SILH versus MILH
131
Table 2 Follow-up time and mesh fixation Study
Duration of follow-up SILH
Type of mesh used (SILH and MILH)
MILH
Mesh fixation technique (SILH and MILH)
SILPEC versus MILPEC Bharathi et al.14 Uchida et al.13 SILTAP versus MILTEP Sato et al.17 (group 1)
3M 1.4 ± 1.2 M
3M 6.5 ± 1.8 M
NA NA
NA NA
NA
NA
A 11 cm × 15 cm piece of polypropylene mesh
Applying titanium spiral tacks (ProTack)
SILTAP versus MILTAP Sato et al.17 (group 2)
NA
NA
A 11 cm × 15 cm piece of polypropylene mesh
Applying titanium spiral tacks (ProTack)
SILTEP versus MILTEP Rui et al.15 Sherwinter7
3.8 (2.0∼5.5) M 1M
3.8 (2.0∼5.5) M 1M
A polypropylene mesh A parietex anatomical mesh
Tai et al.8 Cugura et al.12
8.7 M 11.5 ± 2.5 M
11 M 11 ± 1.6 M
A piece of polypropylene mesh Two pieces measuring 11 × 15 and 4 × 15 cm polypropylene mesh
Kim et al.16
10 D
10 D
A 13 × 9 cm parietex mesh
NA Applying titanium spiral tacks (ProTack) Applying two tacks Mesh was not fixed in the first few cases of SILH patients. But fixation was applying in the rest of SILH patients and performed in the same way as MILH. Applying two tacks (type unknown)
D, day; M, month; MILH, multi-incision laparoscopic hernioplasty; MILPEC, multi-incision laparoscopic percutaneous extraperitoneal closure; MILTAP, multi-incision laparoscopic trans-abdominal pre-peritoneal; MILTEP, multi-incision laparoscopic total extraperitoneal; NA, not available; SILH, single-incision laparoscopic hernioplasty; SILPEC, single-incision laparoscopic percutaneous extraperitoneal closure; SILTAP, single-incision laparoscopic trans-abdominal pre-peritoneal; SILTEP, single-incision laparoscopic total extraperitoneal.
restriction was placed on the search; seven included trials were reported in English and one was reported in Chinese.7,8,12–17 One study was conducted in China,15 two in Japan,13,17 one in Croatia,12 one in the USA,7 one in India14 and two in South Korea.8,16 One study included three group dates and was divided into two groups of comparative dates to allow pooled analysis of the outcomes.17 Two of the records were children who underwent SILPEC,13,14 and six were adults who underwent SILTEP or SILTAP.7,8,12,15–17 Of the four studies that described the exclusion criteria for patients, the most common reason for exclusion was a history of a hypogastric zone operation.12,15–17 All MILH devices were three-port systems, while the SILH devices were of various types. In most of the included studies, the follow-up was less than 12 months (Table 2), meaning that all outcomes – such as complications and recurrence rates – were classified as short-term outcomes. The type of mesh used for the adults in six studies differed (Table 2). Most studies favoured polypropylene mesh,8,12,15,17 while others used parietex anatomical mesh.7,16 In five studies,7,8,12,16,17 the mesh was fixed by applying titanium spiral tacks, while in one study the mesh fixation technique was unclear15 (Table 2). In an identical study, the mesh used and the mesh fixation technique in SILH were exactly as in MILH. Cosmetic outcome was evaluated in only two studies8,14 and in one of them this outcome was not reported as means and standard deviation,14 pain score and analgesia requirements were evaluated in only one study,7,8 leading us to exclude these outcomes from our meta-analysis.
Outcome measurements Complications included hematoma/seroma, peritoneal injury, extensive subcutaneous emphysema, urinary retention, vascular injury, hydrocele, decreased testicular size, wound erythema, wound infection, umbilical hernia and ileus. Subgroup analysis showed no © 2013 Royal Australasian College of Surgeons
significant difference in complications between any comparative subgroup. In the pooled analysis, there was no significant difference in total complications between SILH and MILH, and no significant heterogeneity was observed (Fig. 2a, Table 3). Six studies described the length of hospital stay.7,8,12,15–17 Subgroup analysis showed that hospital stay was not significantly different in any comparative subgroup except SILTAP versus MILTEP, and overall pool estimates showed that there were no significant differences in hospital stay between SILH and MILH. Low heterogeneity was seen across trials (Fig. 2b, Table 4) and no publication bias was absent (P = 0.06). Operative time for unilateral inguinal hernia repair was reported by eight studies,7,8,12–17 but in one of them this outcome was not reported as means and standard deviation and was excluded.14 Subgroup analysis showed that the average operative time for SILPEC and SILTAP for unilateral inguinal hernia repair did not differ significantly compared to conventional technology. Conversely, the pooled estimate in operative time from five CCTs in the SILTEP versus MILTEP subgroup suggested a significant difference. Overall, the pooled estimate of operative time suggested that SILH takes longer than MILH for unilateral inguinal hernia repair, with evidence of significant heterogeneity (Fig. 3a, Table 5), but without publication bias (P = 0.85). Six studies reported operative times for bilateral inguinal hernia repair,7,8,12–14,17 but in one of them this outcome was not reported as means and standard deviation.14 Subgroup analysis showed no significant difference for unilateral inguinal hernia repair between SILH and MILH for each group. Overall estimates also showed that there was no significant difference between SILH and MILH, without evidence of significant heterogeneity (Fig. 3b, Table 6) and without publication bias (P = 0.26).
132
Lai et al.
(a)
Odds ratio (95% Cl)
Study SILPEC versus MILPEC Bharathi et al.14 Subtotal
(b) % Weight
Standardized mean difference (95% Cl) % Weight
Study SILTAP versus MILTAP
0.80 (0.26, 2.53) 20.9 0.80 (0.26, 2.53) 20.9
SILTAP versus MILTAP Sato et al.17 Subtotal
1.19 (0.10, 13.99) 1.19 (0.10, 13.99)
3.9 3.9
Sato et al.17 Subtotal
4.69 (0.22, 101.72) 1.6 4.69 (0.22, 101.72) 1.6
SILTEP versus MILTEP Rui et al.15 Sherwinter7 Tai et al.8 Kim et al.16 Subtotal
1.28 (0.16, 9.97) 5.3 1.23 (0.35, 4.30) 14.6 0.54 (0.16, 1.79) 26.2 0.71 (0.25, 2.06) 27.4 0.79 (0.42, 1.49) 73.5
Overall
0.87 (0.52, 1.47) 100.0
.009830
1 Odds ratio
101.720
8.4 8.4
0.57 (0.08, 1.07)
10.3
0.57 (0.08, 1.07)
10.3
SILTAP versus MILTEP Sato et al.17 Subtotal
SILTAP versus MILTEP Sato et al.17 Subtotal
0.18 (–0.37, 0.73) 0.18 (–0.37, 0.73)
Fig. 2. (a) Forest plots of complications in subgroup analysis by ethnicity using a fix-effect model (contrast SILH versus MILH). (b) Forest plots of hospital stay in subgroup analysis by ethnicity using a fix-effect model (contrast SILH versus MILH).
SILTEP versus MILTEP Rui et al.15
0.53 (–0.07, 1.13)
Sherwinter7
0.00 (–0.38, 0.38)
17.3
Tai et al.8
0.00 (–0.34, 0.34)
21.9
Cugura et al.12
0.00 (–0.59, 0.59)
Kim et al.16
7.1
7.3
–0.21 (–0.51, 0.09)
27.6
Subtotal
–0.02 (–0.20, 0.15)
81.3
Overall
0.05 (–0.11, 0.21)
100.0
–1.1279
0 Standardized mean difference
1.12798
Table 3 Subgroup analysis comparing SILH and MILH for complications 3
Pooled OR
P
Subgroup SILPEC versus MILPEC SILTAP versus MILTAP SILTAP versus MILTEP SILTEP versus MILTEP Overall
0.80 (0.26, 2.53) 1.19 (0.10, 13.99) 4.69 (0.22, 101.72) 0.79 (0.42, 1.49) 0.87 (0.52, 1.47)
0.71 0.89 0.33 0.47 0.61
Test for heterogeneity X2
P
— — — 0% 0%
— — — 0.77 0.88
MILH, multi-incision laparoscopic hernioplasty; MILPEC, multi-incision laparoscopic percutaneous extraperitoneal closure; MILTAP, multi-incision laparoscopic trans-abdominal pre-peritoneal; MILTEP, multi-incision laparoscopic total extraperitoneal; OR, odds ratio; SILH, single-incision laparoscopic hernioplasty; SILPEC, single-incision laparoscopic percutaneous extraperitoneal closure; SILTAP, single-incision laparoscopic trans-abdominal pre-peritoneal; SILTEP, single-incision laparoscopic total extraperitoneal.
Table 4 Subgroup analysis comparing SILH and MILH for hospital stay 4
Pooled SMD
P
Subgroup SILTAP versus MILTAP SILTAP versus MILTEP SILTEP versus MILTEP Overall
0.17 (−0.37, 2.53) 0.57 (0.37, 1.07) −0.03 (−0.20, 0.15) 0.05 (−0.11,0.21)
0.53 0.02 0.79 0.51
Test for heterogeneity X2
P
— — 15.8% 39.3%
— — 0.31 0.13
MILH, multi-incision laparoscopic hernioplasty; MILTAP, multi-incision laparoscopic trans-abdominal pre-peritoneal; MILTEP, multi-incision laparoscopic total extraperitoneal; SILH, single-incision laparoscopic hernioplasty; SILTAP, single-incision laparoscopic trans-abdominal pre-peritoneal; SILTEP, single-incision laparoscopic total extraperitoneal; SMD, standardized mean difference.
Six studies evaluated conversions,7,8,14–17 but only three patients from two studies required conversions.14,17 Conversions were the same in both treatment subgroups, and the overall estimates also showed no significant difference between SILH and MILH, without heterogeneity across trials (Fig. 4a, Table 7), and no publication bias (P = 0.09). Short-term recurrence was evaluated by seven studies,7,8,12–15,17 but present in only three of them.12,14,17 No difference in short-term recurrence was found, and the overall pool estimate continued to show this trend, without heterogeneity across trials (Fig. 4b, Table 8), and without publication bias (P = 0.89).
Sensitivity analysis The inclusion criteria of this meta-analysis were subjected to sensitivity analysis to determine whether modification of the inclusion criteria of the meta-analysis affected the results (Fig. 5a). A single study involved in the meta-analysis was deleted each time to reflect
the influence of each individual data set on the pooled ORs. The corresponding pooled ORs were essentially unaltered (data not shown), indicating that our results were statistically sound.
Risk of publication bias A funnel plot of the studies included in our primary outcome of complications was created to explore publication bias (Fig. 5b). The funnel plot shows the confidence interval (CI) and effect estimate. The latter shows a symmetrical distribution around the effect estimate, indicating that publication bias was likely minimal for studies that evaluated SILH techniques. Although complications were evaluated by eight studies,7,8,12–17 two studies did not have any event in either group and so were not included in the funnel plot.12,13 The funnel plot should be interpreted with caution. Linear regression analysis was not performed to determine funnel plot asymmetry as none of the dichotomous outcomes were included in sufficient trials for this method. © 2013 Royal Australasian College of Surgeons
SILH versus MILH
133
Fig. 3. (a) Forest plots of operative time for unilateral inguinal hernia repair in subgroup analysis by ethnicity using a fix-effect model (contrast SILH versus MILH). (b) Forest plots of operative time for bilateral inguinal hernia repair in subgroup analysis by ethnicity using a fix-effect model (contrast SILH versus MILH).
(a)
(b) Standardized mean difference (95% Cl) % Weight
Study SILPEC versus MILPEC Uchida et al.13 Subtotal
–0.08 (–0.39, 0.23) –0.08 (–0.39, 0.23)
21.2 21.2
SILTAP versus MILTAP Sato et al.17 Subtotal
0.16 (–0.39, 0.71) 0.16 (–0.39, 0.71)
6.8 6.8
SILTAP versus MILTEP Sato et al.17 Subtotal
–0.10 (–0.58, 0.39) –0.10 (–0.58, 0.39)
8.6 8.6
SILPEC versus MILPEC Uchida et al.13 Subtotal
0.06 (–0.26, 0.37)
32.5
0.06 (–0.26, 0.37)
32.5
–0.24 (–0.79, 0.31)
10.4
–0.24 (–0.79, 0.31)
10.4
SILTAP versus MILTAP Sato et al.17 Subtotal
SILTEP versus MILTEP
SILTEP versus MILTEP Rui et al.15 Sherwinter7 Tai et al.8 Cugura et al.12 Kim et al.16 Subtotal Overall
–1.5733
Standardized mean difference (95% Cl) % Weight
Study
0 Standardized mean difference
0.95 (0.33, 1.57) 0.27 (–0.12, 0.65) 0.78 (0.42, 1.13) –0.55 (–1.15, 0.06) 0.29 (–0.02, 0.59) 0.39 (0.21, 0.57)
5.3 13.8 16.5 5.7 22.1 63.4
0.23 (0.09, 0.38)
100.0
1.57335
Sherwinter7
–0.01 (–0.39, 0.38)
21.3
Tai et al.8
0.24 (–0.10, 0.58)
26.9
Cugura et al.12
0.00 (–0.59, 0.59)
9.0
Subtotal
0.11 (–0.12, 0.34)
57.2
Overall
0.06 (–0.12, 0.23)
100.0
–.79241
0 Standardized mean difference
.792419
Table 5 Subgroup analysis according to operation time for unilateral inguinal hernia repair in comparison of SILH and MILH 5
Pooled SMD
P
Subgroup SILPEC versus MILPEC SILTAP versus MILTAP SILTAP versus MILTEP SILTEP versus MILTEP Overall
−0.08 (−0.39, 0.23) 0.16 (−0.39, 0.71) −0.10 (−0.58, 0.39) 0.39 (0.21, 0.57) 0.23 (0.09, 0.38)
0.60 0.57 0.70
