Colorectal and emergency surgical patients in the literature supporting EHS and AHS guidelines on abdominal wound closure: a granular analysis

This study is a structured granular review aiming to critically appraise the evidence base underpinning the 2022 European Hernia Society (EHS) and American Hernia Society (AHS) guidelines on abdominal wall closure, specifically focusing on colorectal and emergency surgery patients [10].

Eligibility: A total of 39 references cited as evidence for the updated EHS/AHS guideline recommendations, including the original 2015 guidelines, were screened for inclusion. Studies were considered eligible if they were referenced to answer the guideline key questions (KQs) (Table 4). Of these, 38 met the inclusion criteria: 19 systematic reviews, 13 randomized controlled trials, 1 literature review, and 5 observational studies. Full-text publications were used for data extraction. When complete datasets were not available, corresponding authors were contacted to request raw data. A reminder was sent after two weeks, and if no reply was received within an additional two weeks, the request was documented as unanswered. For each included study, data were collected using a standardized extraction form (Appendix). When colorectal and/or emergency surgery patients were included, subgroup data were recorded. Extracted information included study design, patient numbers, surgical approach, and type of incision. For the colorectal subgroup, additional details were collected when available, such as surgical indication and the use of prophylactic (parastomal) mesh. Data on interventions, such as incision type, closure technique (e.g., small bites vs. mass closure, continuous vs. interrupted suture, suture material), use of prophylactic mesh, abdominal binders, and postoperative activity restrictions, were also recorded.

The primary outcome of interest was the rate of incisional hernia.

Risk of bias assessments were performed independently by reviewers in duplicate with conflicts settled by consensus (VB, SB, AD, TG, GvR). Systematic reviews and meta-analyses were assessed independently by two reviewers (ME, LM) using the AMSTAR 2 tool [13], randomised controlled trials were assessed using the Cochrane Risk of Bias RoB2 tool [14] and non-randomised studies using the ROBINS-I tool [15]. GRADE was used to assess the quality of the non-randomised studies [16]. Our analysis focused on interpreting the methodological quality of the systematic reviews by assessing adherence to the domains outlined in AMSTAR 2. Descriptive analyses were performed where and when applicable. P-values < 0.05 were considered statistically significant.

Out of the 94 references included in the updated guidelines [10], 39 articles were used to support the recommendations and were therefore considered eligible for analysis. These studies encompassed a cumulative sample of 133,460 patients (n = 37, as one article [17] did not report the number of patients, and the original guidelines [9] were excluded from this sample) — see Table 1.

Five articles were excluded from our analysis as they did not pertain to colorectal or emergency surgical patients [27, 29‐31, 40], in addition to the original guideline article [9].) 33 studies met inclusion criteria and were analysed [26, 28, 32‐39, 41‐55]. These included 12 randomised controlled trials (RCTs) [19, 22, 36‐39, 46‐51], 15 systematic reviews/meta-analyses [18, 23, 32‐35, 41‐45, 52‐55], 1 literature review [28] and 5 observational studies [20, 21, 24‐26]. Among these studies, 32 included colorectal surgical patients [26, 28, 32‐39, 41‐46, 48‐55] and 16 included patients undergoing emergency surgery [28, 32‐38, 41‐43, 45, 47, 49‐51] - see Tables 2 and 3. Among these, 32 studies included colorectal surgery patients [26, 28, 32‐39, 41‐46, 48‐55], and 16 studies included patients undergoing emergency surgery [28, 32‐38, 41‐43, 45, 47, 49‐51]-see Tables 2 and 3.

In total, 32 articles included colorectal patients of which twenty-one discerned the proportions of colorectal patients [18‐26, 32, 36‐39, 42, 43, 46, 48, 51, 53] and [54]) - Table 1. Of these, nine studies focused exclusively on colorectal patients [19‐26] and [37]. Eleven articles did not specify the number of colorectal patients included [28, 33‐35, 41, 44, 45, 49, 50, 52] and [55] and the remaining twelve articles included colorectal patients as part of a heterogeneous group of surgical patients [18, 32, 36, 38, 39, 42, 43, 46, 48, 51, 53] and [54] and indicated the proportion.

Regarding the surgical setting, 24 studies included elective colorectal patients [26, 32‐35, 38, 39, 43‐48, 51, 53‐55] and 10 articles included colorectal emergent patients [32‐34, 36, 37, 43, 45, 49]– [50] − 6 articles included emergent and elective colorectal patients [32‐34, 43, 45] and [51]. None of the articles reported the results separately for colorectal emergent surgery patients.

None of the reviewed articles explored colorectal surgery as a potential risk factor for incisional hernia through univariate or multivariate analyses. Furthermore, none of the articles addressed the usage of parastomal mesh in their analyses.

Only four articles provided separate findings for abdominal emergency patients [37, 47, 49] and [50], while no articles reporting separate findings for emergency colorectal surgery. None of the articles had explored emergency surgery as a potential risk factor for incisional hernia through univariate or multivariate analysis.

Risk assessment tools for incisional hernia were assessed in 3 articles [24‐26]. Table 4 provides a summary of the key characteristics analysed across the included studies regarding incisional hernia risk assessment and related risk/protective measures per key question (KQ) of the updated guidelines [10]. Twenty four articles assessed risk of incisional hernia as an outcome [18‐26, 28, 33, 34, 41‐51], 14 articles assessed closure of laparotomy incisions [32‐39, 42, 47‐51] and 4 articles assessed postoperative care [52‐55].

Key Question 1 explores whether the type of surgical approach or incision affects the risk of incisional hernia. Of the eleven studies cited in the guidelines, ten were analysed (excluding the original guideline [10]), nine of which included colorectal surgery patients—eight with 100% and one with 64.3% colorectal populations”). - Table 4 [18‐26] None of the studies included emergency surgery patients. Four (4/9) studies evaluated the impact of surgical approach on hernia risk [18‐21], while five assessed incision type [22‐26]. Only two had incisional hernia as a primary outcome, and outcome reporting was heterogeneous in terms of definitions, follow-up, and diagnosis; no study stratified results by urgency or indication.

Key Question 2 evaluates whether fascial closure of laparoscopic or robotic ports reduces port-site hernia. Four studies were cited [28‐31], only one [28] of which included colorectal and emergency patients, without specifying proportions or analysing subgroups. None of the studies provided stratified outcomes or specified closure techniques in detail.

Key Question 3 investigates which closure techniques and materials are most effective in laparotomy incisions. Of nine studies cited in the guidelines, eight were included in our analysis. All eight involved colorectal and/or emergency patients, although subgroup proportions were not consistently reported [32‐39]. One study included only colorectal emergency patients [37], two included predominantly colorectal patients [32, 39], one included >50% emergency patients [36], and three did not specify subgroup proportions [33‐35]. Various closure techniques were analysed, including continuous vs. interrupted sutures [33, 34], small-bite technique [33, 39], absorbable vs. non-absorbable sutures [33, 34], and antiseptic (triclosan-coated) sutures [32, 35‐38]. No study was industry-funded.

Key Question 5 addresses whether prophylactic mesh placement at the time of laparotomy closure reduces the risk of incisional hernia in high-risk patients. All eleven studies cited in the guidelines were included in our analysis [41‐51], and all involved colorectal and/or emergency surgery patients. Eight studies reported subgroup proportions [42,43,46,48,51 for colorectal; 47,49–51 for emergency], with two including 100% emergency patients [49, 50]. All studies assessed mesh augmentation; nine detailed mesh positioning, while in two cases it was either unclear or not reported [44, 51]. Four studies were industry-funded [46, 48, 49, 51].While the use of mesh was consistently associated with lower hernia rates, none of the studies stratified this effect by patient type, urgency, or indication.

Key Question 6 evaluates whether postoperative use of abdominal binders reduces the risk of incisional hernia. Three studies were included [52‐54], all of which involved colorectal patients, though only two reported their proportions (6.2% and 34.9%) [53, 54] None of the studies included emergency patients, and outcomes were not stratified by diagnosis or urgency. All studies analysed binder use during postoperative recovery, with heterogeneity in duration, compliance, and definition of hernia.

Key Question 7 examines whether limiting physical activity after open abdominal surgery reduces the risk of incisional hernia. Only one study [55] was included in the guidelines under this question. It involved colorectal patients but did not report their proportion, nor did it include emergency patients. The study evaluated outcomes related to early versus delayed return to normal activity but did not stratify results by patient type or indication.

This is the first article critically appraising the evidence supporting the European and American Hernia Society (EHS/AHS) guidelines on abdominal wall closure in colorectal and emergency surgery patients, adding important data for readers, researchers and policymaker and paving the way for further studies on the topic.

For this inherent methodology we focused solely on the sources included in the 2022 EHS/AHS guidelines, without systematically incorporating newly published studies on the topic [7].

We acknowledge that the reported figure of 133,460 patients represents the total number of patients across the studies cited in the EHS/AHS guidelines, and thus may include overlap between systematic reviews and their underlying primary studies. This figure should therefore be interpreted as a representative measure of the evidence base size, rather than the exact number of unique patients. Our conclusions are based on study quality and inclusiveness of colorectal and emergency subgroups, not on the absolute patient count. We added also this statement in the strength and limitations subsection of the study. Furthermore, where full datasets were not available from the articles or supplementary materials, attempts were made to contact the corresponding authors, but noresponses were received. As a result, our ability to reanalyse or verify subgroup-specific outcomes was limited.

Key Questions 6 and 7, addressing postoperative care and restriction of activity after open abdominal surgery, highlight important gaps in current evidence. Although the use of abdominal binders has been explored in some studies, including one suggesting potential benefits on physical and mental wellbeing [59], this was not incorporated into the guidelines, and the evidence remains insufficient to support clear recommendations. Moreover, the underlying studies were small, with missing data and suboptimal design, limiting their reliability. Regarding activity restriction, no recommendation could be made due to the complete lack of high-quality evidence, underscoring an urgent need for prospective trials and robust observational studies, ideally based on registries with long-term follow-up and standardised definitions.

Overall, the quality of evidence underpinning the guideline recommendations remains low or very low, and the strength of recommendations was generally weak across all key questions. Within both elective and emergency colorectal surgery, further research is needed to clarify the interrelationship between surgical site occurrences, surgical site infections, and incisional hernia development. While SSI is recognised as a major risk factor for incisional hernia [1, 11, 12], the effect of SSI prevention strategies on the incidence of hernia has not been systematically investigated. Notably, although the updated guidelines report no evidence that antimicrobial-coated sutures prevent incisional hernia, the cited studies only had 30 days of follow-up, sufficient for SSI detection but inadequate for hernia assessment. Longer-term studies evaluating the true impact of SSI prevention measures on hernia formation are therefore necessary.

The results of our analysis underscore that baseline data on specific subgroups in the field of abdominal wall closure are still lacking and the generalization based on extending the results from different procedures could introduce further bias rather than overcome the current dilemmas. In a recent metanalysis including 41 Randomized control trials (RCT) and 9 prospective studies [60], small-bites technique with a slowly absorbable suture showed significantly better results over large-bite technique in elective surgery, while continuous modified Smead-Jones suturing showed a significantly better profile in the emergency setting, suggesting that difference may exist between these populations. For elective patients, the long-term outcome data from STICHT trial [61] are awaited shortly and could add further high-quality data to the current debate, even regarding different subgroups of patients.

Future research should also aim at harmonising abdominal wound closure techniques while developing patient-specific approaches based on individual risk factors. Tailored strategies may be particularly beneficial for high-risk subgroups such as those undergoing emergency colorectal surgery. Furthermore, given the significant impact of both SSI and incisional hernia on quality of life, collecting patient-reported outcome measures (PROMs) is essential to investigate the impact of these complications on patients. Outcomes that are meaningful to patients, including perceptions of surgical wound healing, physical function, cosmetic outcomes, and tolerance of supportive interventions such as binders and exercise restrictions, deserve greater attention.