Incisional Hernia Repair: Meta-Analysis on Laparoscopic and Open Surgical Repair

By Rosario Vecchio, Serena Scilletta, Eva Intagliata

Affiliations

1. Department of General Surgery and Medical Surgical Specialities, University of Catania, Policlinico G. Rodolico – San Marco, Catania, Italy

doi: 10.29271/jcpsp.2025.07.886

ABSTRACT
Despite the benefits of laparoscopic surgery, routine laparoscopic treatment of incisional hernia remains controversial. The aim of this meta-analysis was to compare the outcomes after laparoscopic and open incisional hernia repair and to assess the advantages and limitations of these techniques. A literature search was performed from January 2006 to April 2022, using the PubMed and Scopus databases. Six randomised controlled trials, four prospective studies, and five retrospective studies were eligible; however, the meta-analysis was conducted only on the six randomised clinical trials. Laparoscopic repair was associated with a higher incidence of intraoperative complications (risk ratio calculated as open surgery/laparoscopy was 0.18 with a 95% CI from 0.06 to 0.055, p <0.05), whereas open surgery had a highly significant greater risk of surgical site infections (risk ratio calculated as open/laparoscopy was 4.47 with a 95% confidence interval from 2.16 to 9.25, p <0.001). Haematoma and seroma formation had the same rate of incidence after the two approaches. Most of the reviewed articles found a longer hospital stay in the open group, while operation time and time to oral intake did not show a significant difference between the techniques. Most of the reviewed articles suggested a higher risk of intraoperative complications in laparoscopic surgery and a lower risk of postoperative complications in laparoscopy. The recurrence rate was similar after the two approaches, but most of the studies had a short follow-up. Further studies with a longer follow-up are required.

Key Words: Incisional hernia, Laparoscopic repair, Outcomes.

INTRODUCTION

Open and laparoscopic surgery are two valid techniques for repairing incisional hernia. Despite the well- known benefits of laparoscopic surgery over open surgery, which one is the best treatment method for incisional hernia repair, remains contro- versial. As a matter of fact, laparoscopy is less invasive, but there is a lack of evidence supporting the routine use of this surgical technique.

The purpose of this study was to conduct a meta-analysis of relevant articles in literature in order to assess the advantages  and  limitations  of  both  techniques.

METHODOLOGY

A search of the literature was performed from January 2006 to April 2022, using PubMed and Scopus databases. The Medical Subject Headings (MeSH) used were incisional hernia repair, laparoscopic versus open, laparoscopic open comparative, incisional hernia mesh repair, and abdominal wall repair.

The PICOS (patient or problem, intervention, comparison, and outcome) model aided in the definition of the clinical question in terms of the specific patient condition, as well as the identi-fication of clinically relevant data in the Literature. Rando-mised clinical trials have been considered for the statistical meta-analysis, as randomisation reduces the bias by enhancing the probability that factors not included in the study design are uniformly distributed across the study and control groups. In this way, any differences observed between the two groups may be attributed to the treatment.

Studies excluded from the analysis were those about recurrent incisional hernia, those describing a hybrid approach or robotic-assisted approach, those including recurrent incisional hernia, non-comparative studies, and studies not written in the English language.

Six randomised controlled trials,^1-6 four prospective studies,^7-10 and five retrospective studies^11-15 were eligible for this study, but only the randomised ones were selected for the meta- analysis. A graphical illustration of the results is shown in Figure 1.

Data from the literature on patients' characteristics, including the number of patients in each trial and the number of participants in each surgical procedure, are shown in Table I. Data were pooled only if homogeneous.

In the laparoscopic group, all the patients underwent the IPOM (intraperitoneal onlay mesh) procedure, while in the open group, three different techniques were used: Inlay mesh in one study,¹ sublay mesh in four studies,^2,4-6 and onlay mesh in three studies.^1,3,4

Figure  1:   Flow  chart  of  the  researched  studies.

Most of the studies included only adult patients (≥18 years)^1,3-6 and reported median age and interquartile range (IQR); others reported mean age.^2,7-15 The gender of patients was expressed as the number of males and its percentage. Body mass index (BMI) and hernia diameter were expressed as mean, except for Olmi et al., which reported BMI as the median value.¹ Rogmark et al. and Eker et al. expressed hernia diameter as a median value.^5,6

The outcomes of this study consisted of intraoperative and postoperative complications. Intraoperative complications included serosae injuries, bleeding, and iatrogenic injuries. Postoperative complications included the formation of seroma, haematoma, surgical site infections, and a number of recurrences.

Moreover, operative time, time to oral intake, and days of hospital stays were also considered.

According to their nature, outcome variables were divided into two groups: Binary or qualitative (recurrence, intraoperative complications, postoperative complications, formation of seroma, formation of haematoma, and surgical site infections), and continuous or quantitative (operative time, time to oral intake, and days of hospital stay).

To investigate the binary measures, the risk ratio, which is the ratio between the probability of an outcome in the open group and the probability of the same outcome in the laparoscopic group, was used; therefore, the required data were the total number of patients and the number of outcome positivity for each group. Mean and standard deviation were used for  continuous  outcomes.

Since mean and standard deviation were used if data were reported in form of median, interquartile range, and confidence interval, they were estimated with the following formula. To estimate mean (x) using the values of median (m), low and high end of the range (a and b), respectively, and the sample size, n: x ≈ (a + 2m + b) /4.¹⁶ To estimate variance S and standard deviation SD using low and high end of the range a-b and the sample size, 

To estimate standard deviation (SD) using 95% confidence interval (a and b) and the sample size, 

To estimate mean x using median m, interquartile range, q1-q3: x ≈ (q1 + m + q3) / 3.¹⁷ To estimate standard deviation (SD) using interquartile range, q1-q3: SD = (q3-q1) / 1.35.¹⁷

The level of significance was set at 5%, so a p-value of <0.05 was considered statistically significant. MedCalc for the statistical analysis was used.

RESULTS

Four of the six selected studies specified the number of intraoperative complications. In a randomised controlled trial by Eker et al., the total perioperative complication rate after laparoscopic repair was significantly higher than for the open repair (10% vs. 2%, p = 0.05).⁶ A similar result was found by Itani et al., (open group 1.4% vs. laparoscopic group 9.6%, p = 0.05).³

Another randomised clinical trial did not demonstrate any significant difference between the two surgical approaches.⁴ Navarra et al. did not report any intraoperative complications (Table  I).²

For the intraoperative parameter, the test for the null hypothesis of heterogeneity was not statistically significant (p = 0.96), so a fixed-effect meta-analysis was performed. The results indicated a lower risk of intraoperative complications in open surgery compared to the the laparoscopic techniques, with a significant difference between the two methods (p <0.05). The risk ratio in terms of open surgery/laparoscopy was 0.18 with a 95%  CI  from  0.06  to  0.055.

A graphical illustration of the results is shown in the forest plot (Figure  2).

The analysis of results suggested a no significant degree of heterogeneity in postoperative complications (p >0.05), except for wound infection incidence. Thus, a fixed-effects analysis was performed. Even if the results showed a risk ratio of 1.08, so there could be a lower risk for the laparoscopic group. The 95% confidence interval contained the unit (0.69 to 1.68), so this result was not statistically significant (accordingly the p-value was >0.05). Therefore, there was not a significant difference between the two techniques in postoperative complications, except for wound infection incidence. The forest plot shows  the  results  of  this  analysis  (Figure  3).

Table I: Patients’ characteristics and hernia size in each study and in each group. The data are homogeneous except for mesh location.

Author, year	Navarra et al. 2007	Olmi et al. 2007	Asencio et al. 2009	Itani et al. 2010	Rogmark et al. 2013	Eker et al. 2013
Number of patients	24	170	84	146	133	194
Procedure	-	-	-	-	-	-
Open total	12	85	39	73	69	100
Open inlay	-	81	-	-	-	-
Open sublay (Rives)	12	-	12	-	69	100
Open onlay	-	4	27	73	-	-
Laparoscopic IPOM	12	85	45	73	64	94
Age (years)	-	-	-	-	-	-
Open mesh	64.1	median 65 (IQR 20.8)	60.55	59.6	58	56.7
Laparoscopic mesh	59.3	median 60.0 (IQR 8.7)	58.02	61.2	58	59.1
Gender (number and % of male)	-	-	-	-	-	-
Open mesh	3 (25.00%)	35 (41.18%)	11(28.21%)	67 (91.80%)	28 (40.58%)	59 (59.00%)
Laparoscopic Mesh	5 (41.67%)	38 (44.71%)	18 (40.00%)	67 (91.80%)	27 (42.18%)	56 (60.00%)
BMI (mean, kg/m2)	-	-	-	-	-	-
Open mesh	-	median 28 (IQR 8)	30.61	31.20	29.30	29.30
Laparoscopic Mesh	-	median 28 (IQR 7)	31.35	30.60	29.30	28.30
Hernia diameter (mean, cm)	-	-	-	-	-	-
Open Mesh	6.90	10.50	10.19	-	median 5 (IQR 3.6)	median 5 (IQR 4.10)
Laparoscopic Mesh	5.90	9.70	9.51	-	median 5 (IQR 4.7)	median 5 (IQR 4.8)

Figure 2: Forest plot showing intraoperative complications shows a significant lower risk for open group.

Figure 3: Forrest plot of postoperative complications shows no significant differences between two methods.

Figure 4: Forest plot of formation of seroma shows no significant differences between two groups.

Figure 5: Forest plot showing haematoma formation demonstrates no significant differences between two surgical techniques.

Five studies reported data on seroma formation.^1-3,5,6,18 The results of the studies were not homogeneous, in fact, the test for the null hypothesis of heterogeneity was significant (p = 0.02). As a result, a random-effects meta-analysis was performed. There was a risk ratio of 0.74 (calculated as open surgery/laparoscopy), so it could suggest a lower risk in the open group, but 95% confidence interval contained the unit (0.26-2.08). Therefore, there was no significant difference between the two surgical methods (p = 0.57). Figure 4 shows the forest plot illustrating the results of this clinical outcome. Only three studies reported data on haematoma complication.^3,5,6 Inadequate haemostasis is the most common cause of wound haematoma.¹⁹ The degree of heterogeneity in results was not statistically significant between the studies (p = 0.90). Therefore, a fixed-effects model was performed. The risk ratio was 1.09, so it could suggest a lower risk for the laparoscopic group, but 95% CI contained the unit (0.54-2.22). Thus, the difference between methods was not significant (p = 0.81). Figure 5 shows these results from a forest plot.

All studies included in the meta-analysis reported data regarding surgical site infections.^1-6 A surgical site infection is an infection that occurs in the surgical site up to 30 days after intervention and can be superficial or deep. In this outcome, there was no evidence of heterogeneity between studies (p = 0.12), so a fixed-effects model was used. The risk ratio (calculated as open/laparoscopy) was 4.47 with a 95% CI from 2.16 to 9.25, therefore, it did not contain any unit. Therefore, the results suggested a highly significant difference between the two methods (p <0.001). The risk of wound infection was lower for laparoscopy compared to open surgery.

The first continuous outcome was operation time. Five studies reported this information, expressed in minutes.^1,2,4-6 A high degree of heterogeneity between the studies was found in the analysis of the results (p <0.0001), so a random-effects meta-analysis was performed. The results suggested that the mean difference calculated as open minus laparoscopy was 0.42 (that means 25 minutes longer in open than in laparoscopy), but 95% CI contained zero, so there was not a significant difference between the open and laparoscopic surgery in terms of operation time (p = 0.40).

Five of the six studies included in this meta-analysis reported data about recurrence rate but with a different interval of follow-up: Varying from six months;² to one year;⁴ two years;^1,3 and three years.⁶ These follow-up periods are too small to obtain a realistic result and, furthermore, are too different among the studies.^9,20,21 No evidence of hetero-geneity among the studies was found (p = 0.97). The risk ratio (calculated as open/laparoscopy) was 0.74 with a 95% CI from 0.45 to 1.21, therefore, it contained a unit. Thus, there is no significant difference between two surgical techniques (p = 0.22).

The time to oral intake was reported in days by two studies.^2,4 The degree of heterogeneity was not significant (p = 0.38). As a result, a fixed-effects meta-analysis was performed. The standardised mean difference (open minus laparoscopy) was -0.09, suggesting a difference between the two methods of about two hours more after the laparoscopy than after the open surgery. However, the 95% CI contained zero, so the finding was not significant (p = 0.65). Thus, there was no significant difference between these two techniques.

Five studies reported the length of hospital stay expressed in days.^1,2,4-6 Comparing all the studies, the test for the null hypothesis of heterogeneity was significant with a p = 0.001. Thus, a random-effects meta-analysis was performed. Standardised mean difference (calculated as open minus laparoscopy) was 0.35, suggesting a difference of about eight hours more in the open surgery than in laparoscopy. Nevertheless, 95% CI contained zero, so the findings were not statistically significant (p = 0.11). Thus, there was no difference between the two techniques in terms of length of hospital stay.

DISCUSSION

This study compared laparoscopic versus open incisional hernia repair in the existing Literature. Fifteen studies were reviewed and 6 of them with 751 patients were included in the meta-analysis.

Laparoscopic incisional hernia repair is a relatively new and emerging surgical approach that has the potential to replace the open technique but has also the potential for serious complications.

As a result, the small sample size of patients and the short follow-up of the primary studies severely limited the results of this study. In fact, there were very few studies comparing the outcomes of laparoscopic and open approaches for incisional hernia.

Nevertheless, some interesting findings emerged from this meta-analysis. Laparoscopy demonstrated to have a significantly higher risk of intraoperative complications. Even though most of the studies in the Literature showed a lower incidence of postoperative complications in the laparoscopic group, in this meta-analysis there was not a meaningful difference between the two techniques in this outcome, except for wound infection.

Similarly, this meta-analysis and most of the examined publi-cations found no significant difference in seroma formation between the two surgical methods, and only two of them^3,9 showed a significantly higher risk in the open group. Despite most of the selected studies had no significant findings except for three of them,^3,5,15 the statistical analysis revealed a meaningful higher risk in patients undergoing open surgery. On the contrary, all the selected articles concluded that the difference in the risk of haematoma formation between the two approaches was not significant, and the present meta-analysis provided the same conclusion.

This study has shown that the recurrence rate was similar between the two surgical methods, but a clear conclusion cannot be reached because of the different and relatively short follow-up time reported in the articles. However, some studies^5,11,15 showed that the open group has a higher chance of reoperation and readmission because of hernia relapse.

The review of the Literature revealed that each study had different results about the duration of operation and most of them were significant: In fact, six articles demonstrated a longer operation time in the open surgery, while four studies showed that laparoscopic surgery lasted longer. Never-theless, this meta-analysis revealed that there was no significant difference between the two surgical techniques in this outcome.

Only two of the fifteen studies examined time to oral intake,^2,4 and neither demonstrated a significant difference between the two surgical techniques. Even this statistical analysis showed no differences in this outcome. Finally, even though most of the reviewed articles found a longer hospital stay in the open group, in the present meta-analysis, there was no significant difference between the two techniques. This meta-analysis has several limitations. First, post-operative pain and quality of life, both of which are considered critical outcomes for incisional hernia repair, could not be assessed. Only four studies included pain-assessment instruments, and they were used in different ways, so a direct comparison was impossible. Itani et al. used a visual analogue scale (VAS) and the Medical Outcomes Study 36-Item Short Form Health Survey (MOS SF-36) to assess the functional status.³ Eker et al.⁶ studied pain through VAS and postoperative nausea. Asencio et al.⁴ used VAS for pain measuring and EQ5D tariffs for measuring health-related quality of life (HRQoL). Finally, Rogmark et al.⁵ compared postoperative pain three weeks after surgery determined by the bodily pain subscale of the SF-36.

Second, the different and short follow-up time of each study limited the analysis of recurrence. Studies in the Literature demonstrated that a longer follow-up period might result in more hernia recurrence.²² As a result, there was uncertainty about long-term recurrence rates after the two types of hernia surgery, and for this reason, long-term follow-up studies are needed in order to compare the durability of repair. Other systematic reviews on hernia recurrence with a longer follow-up period are required before any definitive recommendations can be issued.

The third limitation was that this meta-analysis considered just three single postoperative complications: formation of seroma, haematoma, and surgical site infection. The authors did not study bowel injury and mesh infections. It would be important because the nature of postoperative problems may have substantial differences between the two procedures. In open repair, most complications were wound-related, seldom needing reoperation, whereas in the laparoscopy there was an important risk of undetected enterotomy. For this reason, cases with a high suspicion of small bowel injury must be converted to routine open repair.^18,19

The fourth limitation was the challenge for obtaining homogeneous data across the six randomised controlled trials because some authors utilised mean and standard deviation, and others used median and IQR. Therefore, this data had to be converted with specific formulas for performing the statistical test.

The last limitation was due to variability in operative technique, in particular mesh location in open repair, because the laparoscopic method was intraoperative onlay mesh (IPOM) in all studies. In fact, in three studies they used sublay position,^2,5,6 while two of them used the onlay method.^3,4 Finally, in Olmi et al.’s study,¹ 95.2% of patients were operated on with inlay mesh and the remaining part with onlay position. This could influence some of the outcomes.

CONCLUSION

Incisional hernia is one of the most common complications after surgery and till now, as it has been detected with the present meta-analysis, it is unclear which one is the best surgical procedure. The authors may suggest that future studies about intraoperative and postoperative compli-cations incidence related to hernia repair should be standardised in the study design, outcomes and follow-up conduct, and a dedicated database should be created.

COMPETING  INTEREST:
The authors declared no conflict of interest.

AUTHORS’  CONTRIBUTION:
RV: Revised the manuscript.
SS: Collected the data.
EI: Wrote the paper.
All authors approved the final version of the manuscript to be published.

REFERENCES

1. Olmi S, Scaini A, Cesana GC, Erba L, Croce E. Laparoscopic versus open incisional hernia repair: An open randomised controlled study. Surg Endosc 2007; 21(4):555-9. doi: 10. 1007/s00464-007-9229-5.
2. Navarra G, Musolino C, De Marco ML, Bartolotta M, Barbera A, Centorrino T. Retromuscular sutured incisional hernia repair: A randomised controlled trial to compare open and laparoscopic approach. Surg Laparosc Endosc Percutan Tech 2007; 17(2):86-90. doi: 10.1097/SLE.0b013e318030ca8b.
3. Itani KM, Hur K, Kim LT, Anthony T, Berger DH, Reda D, et al. Comparison of laparoscopic and open repair with mesh for the treatment of ventral incisional hernia: A randomised trial. Arch Surg 2010; 145(4):322-8; discussion 328. doi: 10.1001/archsurg.2010.18.
4. Asencio F, Aguilo J, Peiro S, Carbo J, Ferri R, Caro F, et al. Open randomised clinical trial of laparoscopic versus open incisional hernia repair. Surg Endosc 2009; 23(7):1441-8. doi: 10.1007/s00464-008-0230-4.
5. Rogmark P, Petersson U, Bringman S, Eklund A, Ezra E, Sevonius D, et al. Short-term outcomes for open and laparoscopic midline incisional hernia repair: a randomised multicenter controlled trial: The ProLOVE (prospective randomised trial on open versus laparoscopic operation of ventral eventrations) trial. Ann Surg 2013; 258(1):37-45. doi: 10.1097/SLA.0b013e31828fe1b2.
6. Eker HH, Hansson BM, Buunen M, Janssen IM, Pierik RE, Hop WC, et al. Laparoscopic vs. open incisional hernia repair: A randomised clinical trial. JAMA Surg 2013; 148(3):259-63. doi: 10.1001/jamasurg.2013.1466.
7. Earle D, Seymour N, Fellinger E, Perez A. Laparoscopic versus open incisional hernia repair: A single-institution analysis of hospital resource utilization for 884 consecutive cases. Surg Endosc 2006; 20(1):71-5. doi: 10.1007/s00 464-005-0091-z.
    
8. Alizai PH, Lelaona E, Andert A, Neumann UP, Klink CD, Jansen M. Incisional hernia repair of medium- and large-sized defects: Laparoscopic IPOM versus open SUBLAY technique. Acta Chir Belg 2019; 119(4):231-5. doi: 10. 1080/00015458.2018.1501962.
9. Kockerling F, Simon T, Adolf D, Kockerling D, Mayer F, Reinpold W, et al. Laparoscopic IPOM versus open sublay technique for elective incisional hernia repair: A registry-based, propensity score-matched comparison of 9907 patients. Surg Endosc 2019; 33(10):3361-9. doi: 10.1007/ s00464-018-06629-2.
10. Kohler A, Lavanchy JL, Gasser R, Wyss R, Nowak L, Scheiwiller A, et al. Mesh fixation to fascia during incisional hernia repair results in increased prevalence of pain at long-term follow up: A multicenter propensity score matched prospective observational study. Surg Endosc 2022; 36(2):951-8. doi: 10.1007/s00464-021-08355-8.
11. Ahonen-Siirtola M, Rautio T, Ward J, Kossi J, Ohtonen P, Makela J. Complications in laparoscopic versus open incisional ventral hernia repair. A retrospective comparative study. World J Surg 2015; 39(12):2872-7. doi: 10.1007/ s00268-015-3210-6.
12. Asti E, Sironi A, Lovece A, Bonitta G, Bonavina L. Open versus laparoscopic management of incisional abdominal hernia: Cohort study comparing quality of life outcomes. J Laparoendosc Adv Surg Tech A 2016; 26(4):249-55. doi: 10.1089/lap.2016.0060.
13. Soliani G, De Troia A, Portinari M, Targa S, Carcoforo P, Vasquez G, et al. Laparoscopic versus open incisional hernia repair: A retrospective cohort study with costs analysis on 269 patients. Hernia 2017; 21(4):609-18. doi: 10.1007/ s10029-017-1601-3.
14. Lavanchy JL, Buff SE, Kohler A, Candinas D, Beldi G. Long-term results of laparoscopic versus open intraperitoneal onlay mesh incisional hernia repair: A propensity score-matched analysis. Surg Endosc 2019; 33(1):225-33. doi: 10.1007/s00464-018-6298-6.
15. Henriksen NA, Friis-Andersen H, Jorgensen LN, Helgstrand F. Open versus laparoscopic incisional hernia repair: Nationwide database study. BJS Open 2021; 5(1):zraa010. doi: 10.1093/bjsopen/zraa010.
16. Hozo SP, Djulbegovic B, Hozo I. Estimating the mean and variance from the median, range, and the size of a sample. BMC Med Res Methodol 2005; 5:13. doi: 10.1186/1471- 2288-5-13.
17. Wan X, Wang W, Liu J, Tong T. Estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range. BMC Med Res Methodol 2014; 14:135. doi: 10.1186/1471-2288-14-135.
18. Goodney PP, Birkmeyer CM, Birkmeyer JD. Short-term outcomes of laparoscopic and open ventral hernia repair: A meta-analysis. Arch Surg 2002; 137(10):1161-5. doi: 10. 1001/archsurg.137.10.1161.
19. Kyzer S, Alis M, Aloni Y, Charuzi I. Laparoscopic repair of postoperation ventral hernia. Early postoperation results. Surg Endosc 1999; 13(9):928-31. doi: 10.1007/s0046 49901137.
20. Ballem N, Parikh R, Berber E, Siperstein A. Laparoscopic versus open ventral hernia repairs: 5-year recurrence rates. Surg Endosc 2008; 22(9):1935-40. doi: 10.1007/s00464- 008-9981-1.
21. Martins MR, Santos-Sousa H, do Vale MA, Bouca-Machado R, Barbosa E, Sousa-Pinto B. Comparison between the open and the laparoscopic approach in the primary ventral hernia repair: A systematic review and meta-analysis. Langenbecks Arch Surg 2024; 409(1):52. doi: 10.1007/s00423-024- 03241-y.
22. Juvany M, Hoyuela C, Carvajal F, Trias M, Martrat A, Ardid J. Long-term follow-up (at 5 years) of midline incisional hernia repairs using a primary closure and prosthetic onlay technique: Recurrence and quality of life. Hernia 2018; 22(2):319-24. doi: 10.1007/s10029-018-1730-3.