Groin hernia repair is globally performed in more than 20 million patients per year [1,2,3,4,5]. Multiple surgical techniques exist to repair groin hernias with variable outcomes. Despite guidelines [6,7,8], there is significant worldwide diversity in management of groin hernias, depending on surgeons' expertise, patients characteristics, local resources, reimbursement systems and cultural differences between regions.

In 2018, the HerniaSurge group, a joint initiative of seven scientific surgical societies with a focus on hernia surgery, published the first International Guidelines for Groin Hernia Management [9]. These guidelines were developed according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) system [10, 11], and were endorsed by the European Hernia Society (EHS), the Americas Hernia Society (AHS), The Asian-Pacific Hernia Society (APHS), the Afro Middle East Hernia Society (AMEHS), the Australasian Hernia Society, the European Association for Endoscopic Surgery (EAES) and International Endohernia Society (IEHS) [12,13,14,15,16,17,18]. However, acceptance among general surgeons remains unknown. A modified consensus method was developed to gauge the degree of agreement with the guidelines among health care professionals. This manuscript presents the outcomes of consensus conferences both in-person and online.

Methods

The International Guidelines on Groin Hernia Management were developed by a working group of 50 hernia experts, called the ‘HerniaSurge’ group [9]. All experts had clinical and scientific expertise in groin hernia surgery. Research questions were formulated and assigned to groups of two or three experts. Critical appraisal of the literature was performed according to Evidence-Based Medicine (EBM) rules and the GRADE approach [11, 19, 20]. During several meetings, results were discussed within the working group. Chapters were written and statements and recommendations were formulated. The Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument was used for the guideline development process to ensure the highest standard for quality [21]. Finally, the guidelines were validated by three external reviewers.

A face-to-face expert consensus meeting among the HerniaSurge members was held in Rotterdam on June 5th 2016 to discuss the final statements and recommendations. A modified Delphi method was used. All statements and recommendations with level of evidence were presented. Discussion was initiated by presenting a summary of the reviewed literature pertaining to that specific topic. The experts voted on the eligibility of each recommendation for voting at international plenary consensus conferences. Refraining from voting was not allowed. Statements and recommendations that all HerniaSurge members agreed on were included for the plenary consensus conferences. Finally, 46 items from the international guidelines for groin hernia management were selected as most important and renewing (See “Appendix”).

International plenary consensus conferences

Plenary consensus conferences were organized at four international congresses: the European Hernia Society (EHS) Congress 2016 in Rotterdam, The Netherlands; the European Association for Endoscopic Surgery (EAES) Congress 2016 in Amsterdam, The Netherlands; the Asian-Pacific Hernia Society (APHS) Congress 2016 in Tokyo, Japan; and the Americas Hernia Society (AHS) Congress 2017 in Cancun, Mexico. Forty-six key statements and recommendations were presented at each conference chaired by an independent coordinator (NvV).

Before the start of each congress, society members were e-mailed with the announcement of the plenary consensus conference. Additionally, a concept of the international guideline on groin hernia management was published online to provide background information prior to the consensus conferences.

At the plenary consensus conferences, key statements and recommendations were presented in seven categories: ‘Groin Hernias,’ ‘General Aspects,’ ‘Open Groin Hernia Repair,’ ‘Laparo-endoscopic Groin Hernia Repair,’ ‘Bilateral, Femoral and Incarcerated Hernias,’ ‘Outcomes,’ and ‘Organization of Care.’ All items were displayed with the original research question, the level of evidence and strength of the recommendation. Additionally, all congress delegates were asked four baseline questions about their profession, continental origin, yearly number of groin hernia repairs they performed and their preference for surgical repair method.

Congress delegates were given one minute per statement or recommendation to vote. There were three voting options for statements and four options for recommendations (Table 1). Voting at the plenary consensus conferences was performed using a digital voting system accessible via an app or online website. Consensus was defined as agreement by more than 70% of the participants.

Table 1 Answer possibilities at the plenary consensus conferences and web survey

Due to logistical reasons, live voting was not possible at the APHS in Tokyo. Alternatively, all statements and recommendations were presented in a plenary presentation and paper questionnaires were handed out to all congress delegates after the session. The paper questionnaires contained all statements and recommendations with the voting options. Completed questionnaires could be returned during the rest of the congress at the HerniaSurge booth in the main hall of the congress building.

After each congress, the 46 key statements and recommendations were entered into a web survey and sent by e-mail to all members of the corresponding hernia society. The e-mail referred to the recent plenary consensus conference. Members that were unable to attend the congress were invited to cast their vote through the online web survey. Voting options were the same as the abovementioned. There was no time limit to complete the web survey. The web surveys were launched after each congress, and open until April 1st 2017.

SPSS was used to analyze the outcomes per hernia society. A Chi-square test was performed to determine whether baseline characteristics differed between hernia societies.

Results

In total 822 (range 723–1072) participants cast their votes either in-person or online: 303 EHS delegates (213 on-site, 90 via web survey), 404 EAES members (181 on-site, 223 via web survey), 233 AHS delegates (84 on-site, 149 via web survey), and 132 APHS members (54 on-site, 78 via web survey). A majority of the participants was either a surgeon (65,8%) or a hernia expert surgeon (23,1%). Continental origin corresponded for all hernia societies, except for the APHS where 44,7% (59/132) of the participants was from Asia. A similar group of 39% (52/132) participants at this congress originated from Europe. The expertise among participants is reflected by yearly number of groin hernia repairs: 30,5% of the respondents performed over 100 repairs per year and 32,4% performs 51–100 repairs annually (Fig. 1). Preference for surgical technique was in 30,9% a Lichtenstein repair, in 29,6% a laparoscopic totally extraperitoneal repair (TEP) and 24,3% a transabdominal preperitoneal repair (TAPP) (Fig. 2).

Fig. 1
figure 1

Annual number of groin hernia repairs per society member

Fig. 2
figure 2

Preferred method of groin hernia repair (> 60% of the cases) per society member

Baseline characteristics were found not to be significantly different between hernia societies, χ2(1) = 46.06, p > 0.05. Level of Evidence (LoE), as determined by the HerniaSurge working group, will be provided after each statement or recommendation. The level of consensus (LoC) will be provided in the calculated percentage.

Groin hernias

Consensus was reached on all statements and recommendations in the category ‘Groin Hernias’ (Fig. 3).

Fig. 3
figure 3

Level of consensus for each statement and recommendation on Groin hernias

There was consensus in 94% that the presence of a groin hernia can be confirmed by physical examination alone in the vast majority of patients with appropriate signs and symptoms (LoE: low; LoC: 94%). Ultrasonography is the preferred imaging when there is doubt about the presence of a groin hernia [22] while MRI, CT or herniography are alternatives [23].

Intrinsic risk factors for the development of primary inguinal hernias include inheritance, a previous contra-lateral hernia, male gender, age and abnormal collagen metabolism [24,25,26,27,28,29]. Acquired risk factors for the development of primary inguinal hernias are previous prostatectomy and low body mass index [30,31,32,33,34,35]. Perioperative risk factors for recurrence like poor surgical technique, low surgical volume, and surgical inexperience should be considered in the management of groin hernia patients (LoE: low; LoC: 92%).

The EHS classification system is suggested to stratify inguinal hernia patients for tailored treatment, research and audit (LoE: low; LoC: 81%) [36].

Symptomatic groin hernias should be treated surgically. Asymptomatic or minimally symptomatic inguinal hernia patients may be managed with “watchful waiting” since their risk of hernia-related emergencies is low. The majority of these individuals will eventually require surgery, and surgical risks and the watchful waiting strategy should be discussed with patients (LoE: High; LoC: 89%) [37,38,39,40].

General aspects

Consensus was reached on seven recommendations on ‘General aspects’ (Fig. 4). No consensus was reached on one statement and four recommendations. The statement without consensus concerned the benefits of so-called lightweight meshes in inguinal hernia surgery (LoE: low; LoC: 69%). The recommendations without consensus concerned the cost-effectiveness of day-case laparo-endoscopic surgery (LoE: moderate; LoC: 69%), no antibiotic prophylaxis in average-risk patients in a low-risk environment in open mesh repair (LoE: high; LoC: 67%), no antibiotic prophylaxis in average-risk patients in any environment in laparo-endoscopic repair (LoE: low; LoC: 63%) and general or local anesthesia over regional in patients aged 65 and older (LoE: low; LoC: 55%).

Fig. 4
figure 4

Level of consensus for each statement and recommendation on General aspects

One standard repair technique for all groin hernias does not exist. It is recommended that surgeons/surgical services provide both anterior and posterior approach options (LoE: very low; LoC: 91%). Surgical treatment should be tailored to the surgeon’s expertise, patient- and hernia-related characteristics and local/national resources (LoE: very low; LoC: 96%) [41]. HerniaSurge suggests Lichtenstein or a laparo-endoscopic repair as optimal techniques. Provided that resources and expertise are available, laparo-endoscopic techniques have faster recovery times, lower chronic pain risk and are cost-effective [42,43,44,45,46,47,48,49,50,51,52,53,54,55].

Mesh repair is recommended as the first choice, either by an open procedure or a laparo-endoscopic repair technique (LoE: moderate; LoC: 95%) [56]. Surgeons should be aware of the intrinsic characteristics of the meshes they use (LoE: low; LoC: 96%).

Day surgery is recommended for simple groin hernia provided aftercare is organized and suggested for selected other cases (e.g., after local anesthetic in ASA III patients) (LoE: moderate; LoC: 95%) [55, 57, 58].

Local anesthesia in open repair has many advantages and is suggested to be used (especially in patients with severe systemic disease) provided the surgeon is experienced in this technique (LoE: high; LoC: 76%) [59,60,61,62,63,64]. Perioperative field blocks are recommended in all cases of open repair (LoE: high; LoC: 84%) [65,66,67,68,69].

Open groin hernia repair

Consensus was reached on all statements and recommendations on ‘Open Groin Hernia Repair’ (Fig. 5).

Fig. 5
figure 5

Level of consensus for each statement and recommendation on Open groin hernia repair

In open surgery, Lichtenstein repair is recommended over a pre-peritoneal mesh repair (LoE: very low; LoC: 75%) [70, 71]. The use of open non-mesh repair in specific patients or types (e.g., young males with lateral hernia L1) of inguinal hernia as an acceptable alternative to a Lichtenstein technique requires further studies (LoE: low; LoC: 71%).

In case a non-mesh inguinal hernia repair will be performed, the Shouldice technique is recommended since it has lower recurrence rates than other suture repairs (LoE: moderate; LoE: 77%) [56].

Despite comparable results, three-dimensional implants (plug-and-patch and bilayer) are not recommended because of the excessive use of foreign material, the need to enter both the posterior and anterior planes and the additional cost (LoE: low; LoC: 82%) [72,73,74,75].

Nerve anatomy awareness and recognition during surgery is recommended to reduce the incidence of chronic post-herniorrhaphy pain (LoE: low; LoC: 94%). During open surgery, planned prophylactic ilioinguinal nerve resection is not suggested since it does not reduce chronic pain incidence and it increases the incidence of postoperative sensory loss (LoE: low; LoC: 83%) [76]. Pragmatic resection of the ilioinguinal nerve and/or the iliohypogastric nerve is recommended if iatrogenic nerve injury occurs or if the nerve(s) interfere(s) with mesh position (LoE: low; LoC: 91%) [77].

Laparo-Endoscopic groin hernia repair

Consensus was reached on all statements and recommendations on ‘Laparo-endoscopic Groin Hernia Repair’ (Fig. 6).

Fig. 6
figure 6

Level of consensus for each statement and recommendation on Laparo-endoscopic groin hernia repair

For male patients with primary unilateral inguinal hernia, a laparo-endoscopic technique is suggested because of a lower postoperative pain incidence and a reduction in chronic pain incidence, provided that a surgeon with specific expertise and sufficient resources is available. However, there are patient and hernia characteristics that warrant a Lichtenstein as first choice (LoE: moderate; LoC: 73%) [78].

TAPP and TEP have similar operative times, overall complication risks, postoperative acute and chronic pain incidence, and recurrence rates (LoE: moderate; LoC: 72%) [78,79,80,81,82,83,84,85,86]. Since TAPP and TEP have comparable outcomes, it is recommended that the choice of the technique should be based on the surgeon’s skills, education, and experience (LoE: moderate; LoC: 94%).

In almost all cases, mesh fixation in TEP is unnecessary. In both TAPP and TEP it is recommended to fix the mesh in large direct hernias (M3-EHS classification) to reduce recurrence risk (LoE: very low; LoC: 85%).

It is recommended that the contra-lateral groin be inspected at the time of TAPP repair. If a contra-lateral inguinal hernia is found at the time of surgery and prior informed consent was obtained, repair is recommended (LoE: very low; LoC: 85%) [87, 88].

Bilateral, femoral and incarcerated hernias

Consensus was reached on all recommendations on ‘Bilateral, Femoral, and Incarcerated Hernias’ (Fig. 7).

Fig. 7
figure 7

Level of consensus for each recommendation on Bilateral, femoral and incarcerated hernias

Primary bilateral inguinal hernias are recommended to be repaired laparo-endoscopically (LoE: low; LoC: 91%). There is discussion concerning the laparo-endoscopic management of potential bilateral hernias (occult hernia issue). After patient consent, during TAPP, the contra-lateral side can be inspected. This is not suggested during unilateral TEP repair.

Provided expertise is available, women with groin hernias are suggested to undergo timely laparo-endoscopic mesh repair in order to decrease chronic pain risk and avoid missing a femoral hernia (LoE: moderate; LoC: 77%) [89,90,91].

In the case of elective femoral hernia repair mesh is recommended to be used (LoE: low; LoC: 92%) [92, 93].

Risk factors for incarceration/strangulation include female gender, femoral hernia presence, and a history of hospitalization related to groin hernia [28, 94,95,96,97]. It is suggested that treatment of emergencies is tailored according to patient- and hernia-related factors, local expertise, and resources. Monofilamental large pore polypropylene mesh-based repair is suggested in emergent groin hernia surgery with a clean or clean-contaminated surgical field (LoE: low; LoC: 73%) [98, 99].

Outcomes

Consensus was reached on five of the six recommendations concerning ‘Outcomes’ (Fig. 8). On the recommendation about immediate re-operation in patients with immediate postoperative pain, there was no agreement (LoE: very low; LoC: 59%).

Fig. 8
figure 8

Level of consensus for each recommendation on Outcomes

After groin hernia repair an early return to normal activities can be safely recommended (LoE: low; LoC: 83%) [100].

Chronic postoperative inguinal pain (CPIP) is a serious complication affecting 10–12% of inguinal hernia repair patients [101,102,103]. It is defined as bothersome moderate pain impacting daily activities lasting at least 3 months postoperatively [104]. CPIP risk factors include young age, female gender, high pre-operative pain, early high postoperative pain, recurrent hernia and open repair [7, 105].

It is suggested that CPIP management is performed by multidisciplinary teams (LoE: low; LoC: 94%) [106]. It is also suggested that CPIP is managed by a combination of pharmacological and interventional measures. If this is unsuccessful, management should be followed by, in selected cases, (triple) neurectomy and (in selected cases) mesh removal [107].

Recurrence rates after inguinal hernia repair can be as high as 15% [108]. For recurrent hernias after failed anterior tissue or mesh repair, posterior repair is recommended (LoE: moderate; LoC: 91%). If recurrence occurs after a posterior repair, an anterior repair is recommended (LoE: moderate; LoC: 88%). After a failed anterior and posterior approach, management by a dedicated hernia surgeon is recommended (LoE: low; LoC: 96%).

Organization of care

Consensus was reached on all statements and recommendations concerning the ‘Organization of Care’ (Fig. 9).

Fig. 9
figure 9

Level of consensus for each statement and recommendation on Organization of care

A goal-directed curriculum including review of anatomy, procedure steps, intraoperative decision making and proficiency-based, simulation enhanced technical skills training should be available to trainees whenever possible (LoE: moderate; LoC: 97%) [109].

In order for centers and surgeons to be certified as either a hernia center or a hernia specialist, minimal requirements on numbers of operations, follow-up and quality control should be met (LoE: very low; LoC: 85%) [110].

The development and implementation of national groin hernia registries in every country is suggested (LoE: low; LoC: 90%). They should include long-term patient follow-up data and account for local healthcare structures.

Due to a substantial lack of access to surgery, inguinal hernia prevalence in low resource settings is too high (LoE: moderate; LoC: 73%) [111,112,113,114,115,116]. Dissemination and implementation plans of the guidelines are recommended to be developed by global (HerniaSurge), regional (international societies) and local (national societies/chapters) initiatives through internet websites, social media and smartphone apps (LoE: very low; LoC: 87%) [117, 118].

It is suggested that in low resource settings the focus is on performing high-volume Lichtenstein repair under local anesthesia using a low-cost mesh (LoE: low; LoC: 87%) [119].

An overarching plan to improve access to safe inguinal hernia surgery in low resource settings is needed [120]. It is suggested that this plan contains simple guidelines and a sustainability strategy allowing implementation and maintainability, independent of international aid (LoE: low; LoC: 89%).

Discussion

This study shows 87% (range 55–97%) consensus on the key statements and recommendations from the International Guidelines for Groin Hernia Management. Consensus, defined as more than 70% agreement among participants, was reached in 87% (34/39) of recommendations and in 86% (6/7) of statements. No consensus was obtained on one statement and on five recommendations, concerning the categories ‘General Aspects’ and ‘Outcome.’ The high level of agreement by so many surgeons working worldwide is an indication of high support of the content of the international guidelines.

Developing guidelines internationally poses challenges to ensure and monitor the dissemination of the content. Its implementation is subject to local working conditions, availability of resources, local economy, cultural differences, diversity in reimbursement systems and differences in logistical capabilities [121, 122]. The plenary consensus conferences at four international congresses served as a means to disseminate the content of the international guidelines and to study the level of consensus among the surgical community.

In our study 822 participants cast their votes. This response rate is higher than in a previous consensus conference on groin hernias [8]. The number of participating EHS, EAES and AHS members was comparable, whereas from the APHS there were only 132 participants. Partly this can be explained by the use of paper questionnaires instead of live voting. A majority of the respondents (540 physicians) completed the web survey. Despite this reasonable number, a higher response rate might have been reached through sending reminders. Optimal use of repetitive emails, internet, and social media might contribute to a higher number of respondents in the future.

In spite of the small number of participating surgeons, assumably a relatively large number of participants are dedicated hernia surgeons. This is reflected by the high number of hernia operations performed per participant annually. The level of experience among the participants was high, with 62.9% of the participants performing more than 50 repairs annually. The expertise among consensus participants is a strength of this study.

The average annual number of groin hernia repairs per surgeon was lower for EAES delegates, which can be explained by the fact it is a laparo-endoscopic society and not a society dedicated to hernia surgery alone. Although EAES members are laparo-endoscopic experts, only 43% favored TAPP or TEP over Lichtenstein (39,8%). It is remarkable that representatives of a laparo-endoscopic society favor an open procedure in daily practice.

The preferred laparo-endoscopic method of repair was TEP for all societies. Whereas the mesh plug technique is a popular procedure for inguinal hernia repair in Asia –mainly Japan– [123] the preferred method among the APHS members was a TEP (35,3%), possibly explained by the relatively high number of European (39%) participants at this congress. Specification of the continental origin and the preference of surgical technique can provide clarity on these results. For all hernia societies, there is a potential bias in the diversity of surgeons that voted.

No consensus could be reached on the use of light versus heavy-weight meshes (69%), superior cost-effectiveness of day-case laparo-endoscopic repair (69%), omitting prophylactic antibiotics in hernia repair, general or local anesthesia over regional in elderly patients (55%) and acute re-operation in case of immediate postoperative pain (59%). As we did not ask voters for their motivations we can only guess for explanations. Discrepancies can be related to inconclusive (low) evidence, conflicting national protocols, personal experience, cultural differences or financial aspects. Recommendations without consensus give directions for future research.

Our results show that antibiotic prophylaxis remains a controversial issue worldwide. Despite a high level of evidence, no consensus could be reached on omitting antibiotics in open repair (67%). Neither consensus was reached for omitting antibiotics in laparo-endoscopic repair (63%). Differences were distinguished between continents as well: 79% and 75% consensus among EHS-members on omitting antibiotic prophylaxis in respectively open and laparo-endoscopic repair, versus only 46% and 39% agreement among AHS delegates. The same recommendations were already published in 2009 in the European guidelines for inguinal hernia [6]. Whereas these recommendations seem to have changed daily practice in European countries, implementation in the United States awaits. A possible explanation may be the recommendation of antibiotic prophylaxis in hernia surgery by other guidelines [124]. Furthermore, prophylactic antibiotics are a required indicator and considered a quality measure by Centers for Medicare and Medicaid Services [9]. Medico-legal aspects potentially play a role in the USA. Conflicting evidence confirms the ambiguity on this topic [125].

Day surgery for groin hernia repair has become increasingly common over the past several decades. Although there was 95% consensus that groin hernia surgery can be performed in day surgery, there was only 69% consensus on the cost-effectiveness of day-case laparo-endoscopic repair. This suggests implementation issues with laparo-endoscopic surgery. Financial incentives and judicial prescriptions might play a role since several countries require a hospital stay after certain types of surgery [126, 127]. The variety in reimbursement policies can be an explanation, but could not be confirmed in this study.

Whereas 81% of all responders are in favor of the EHS classification system for research and quality purposes, only 69% of the AHS delegates agreed with this recommendation. This outcome suggests a lower level of acceptance of the EHS classification in the USA. A possible explanation could be the development by European surgeons or discrepancies between the EU and the USA [36, 128].

A limitation of this study is the involvement of only 822 participants. There are over one million specialist surgeons worldwide [129]. The involvement of only a limited number of participants in this consensus study should be critically analyzed.

Lack of a formal consensus conference method can be considered another limitation. Despite the widespread utility of consensus methods, guidelines for conducting consensus studies are lacking [130]. Existing formal consensus methods often synthesize the best available evidence or reflect the opinion of a small number of experts [131,132,133,134,135,136,137]. This introduces a bias of highly present knowledge, whereas in the general surgical community other ideas prevail. Modified consensus development conferences with the involvement of the general community have been initiated before, but were limited to Europe only [138], conducted online [139] or had a limited number of participants [6]. The consensus conferences of this study introduce a new research method involving the general surgical community.

A third limitation of this study was the dependency on the logistic circumstances, such as the location and timing of congresses, the conference program, and participation of congress organizations to host the plenary consensus meetings. All consensus conferences needed to be hosted shortly after the online publication of the draft guidelines to facilitate participants with access to background information. Conducting an online consensus study only would limit time and costs. However, organizing face-to-face consensus conferences creates more awareness and promotes implementation of the new guideline.

The literature review deadline was July 2015 and new studies were published after this date. This can be considered a limitation because outcomes of new studies have consequences for statements and recommendations. The necessity of updating will always be the case in writing guidelines and consensus development processes.

Lastly, organizing consensus conferences will always require an investment of time and money. Many countries around the world do not have the resources, either in expertise or financially, that are needed. Therefore, it can be argued that the development of international guidelines and global consensus benefits health professionals and patients all around the globe.

Conclusion

The consensus conferences showed 87% consensus on the key statements and recommendations of the first International Guidelines for Groin Hernia Management. No consensus was reached on the use of light versus heavy-weight meshes (69%), superior cost-effectiveness of day-case laparo-endoscopic repair (69%), omitting prophylactic antibiotics in hernia repair, general or local versus regional anesthesia in elderly patients (55%) and re-operation in case of immediate postoperative pain (59%). Relevant understanding can be obtained about acceptability of the recommendations and the guideline. The outcomes of this study provide a solid basis for standardizing the care path of patients with groin hernias and identifying future research questions.