Introduction

Hiatal hernia describes a dilated esophageal hiatus through which the gastroesophageal junction protrudes, and in the maximum variant the entire stomach and other intestinal organs can be displaced in the thorax [1]. There are four types of hiatal hernias (I–IV), with type I (sliding hernia) being the most frequent variant. Intra-abdominal pressure (e. g. chronic obstructive pulmonary disease or chronic constipation) and congenital causes are assumed to be the causes of hiatal hernias [2]. Around 80–90% of hiatal hernias are associated with gastroesophageal reflux disease (GERD), especially in type I hernias [3]. The indication for surgical treatment depends on the extent of the hernia morphology and the clinical symptoms.

Surgical treatment in type I hiatal hernias (sliding hernias) predominantly aims to control the GERD symptoms if medical treatment fails [3,4,5]. Here, usually anti-reflux techniques such as a Nissen or Toupet fundoplications are used, creating a sleeve around the gastroesophageal junction to reinforce the distal esophageal sphincter [1]. In most procedures a cruroplasty is performed to narrow the hiatal orifice [6]. Although recurrence rates of 59% following pure suture cruroplasty after 5 years are described [7] it still remains controversial, if mesh reinforcement of the cruroplasty should be performed [8]. Guidelines from the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) and the European Association of Endoscopic Surgery (EAES) see advantages in terms of a lower recurrence rate after mesh reinforcement, but do not recommend routine mesh implantation in the treatment of GERD of type I hiatal hernias due to insufficient literature evidence and a relevant mesh-associated complication potential such as dysphagia and erosion of the esophagus [5]. As a consequence, indications for mesh should be limited to patients with weak crurae and a larger hiatal defect [9]. The benefit of using a mesh augmentation of the cruroplasty in type I hernias may not outweigh the concerns of mesh-associated complications. However, there are some data supporting the use of a mesh in type I hiatal hernias augmenting the cruroplasty [9,10,11] reducing recurrence and intrathoracic wrap herniation. For decision pro or against a mesh augmentation, some authors suggest a patient tailored algorithm, taking hiatal hernia type, hiatal diameter, tropism of the hiatal pillars and presence of recurrence into account [7,8,9,10,11,12,13] But the controversy underlines the lack of high-evident data to support or refuse a routine mesh reinforcement of the cruroplasty during type I hiatal hernia repair.

Therefore, this matched pair analysis investigates the effect of mesh augmentation of the cruroplasty during type I hiatal hernia repair with data derived from the Herniamed registry.

Methods

The Herniamed Registry is a multicenter, internet-based hernia registry [12] with 936 participating hospitals and surgeons (status April 2023) in private practice (Herniamed Study Group) in Germany, Austria, and Switzerland who have entered data on their patients undergoing routine hernia surgery. All patients signed an informed consent agreeing to participate. As part of the information provided to patients regarding participation in the Herniamed Quality Assurance Study and signing the informed consent declaration all patients were informed that the treating hospital or medical practice should be informed about any problem occurring after the operation and that the patient should have a clinical examination if needed. All postoperative complications occurring up to 30 days after surgery were recorded. At 1-year follow-up, postoperative complications were once again reviewed when the general practitioner and patient completed a questionnaire [12]. At 1-year follow-up, the general practitioner and the patient were also asked about any recurrences, pain at rest, pain on exertion, and chronic pain requiring treatment. If a recurrence, pain, secondary hemorrhage, or blood effusion are reported by the general practitioner or the patient, the patient can be requested to attend clinical examination.

The present retrospective analysis of prospective data compares the perioperative and 1-year follow-up data between October 2009 and March 2022 in patients undergoing type I hiatal hernia repair. Inclusion criteria were fully documented elective primary laparoscopic axial hiatal hernia repairs with Toupet or Nissen fundoplication in patients with GERD, minimum valid age of 16 years and complete 1-year follow-up. In a registry the individual surgeon of the participating institutions decide about the type of fundoplication and the additionally use of a mesh.

All statistical analyses were performed using the software SAS 9.4 (SAS Institute Inc., Cary, NC, USA) and intentionally calculated to a full significance level of 5%, i.e., they were not corrected with respect to multiple testing. For unadjusted comparison of parameters between female and male patients (to present the differences between the original pre-matched samples), χ2 test and t tests (Satterthwaite) were performed for categorical and continuous variables, respectively.

Pairs of mesh and non-mesh patients were matched using a 1:1 propensity-score matching with a greedy algorithm and a caliper of 0.2 standard deviations. The variables used for matching were as follows: age, weight and morbid obesity (classification of body mass index (BMI, kg/m2)), defect size, American Society of Anesthesiologists (ASA) status, preoperative pain, regurgitation, dysphagia, anemia/hemorrhage, lung disorders and presence of at least one further risk factor (chronic obstructive pulmonary disease, diabetes mellitus, aortic aneurysm, immune suppression, cortisone medication, smoking, coagulopathy, anticoagulant, or antiplatelet medication) as well as sex and type of fundoplication (Nissen, Toupet). The last two were used as fixed matching variables, i.e., there must be no deviation within the matched pair.

The balance of the matched sample was assessed using standardized differences (also given for the pre-matched sample), which should not exceed 10% (< 0.1) after creating matched pairs. Matched samples were then analyzed for intraoperative complications, general complications, postoperative complications, complication-related reoperations, recurrence on 1-year follow-up, pain on exertion on 1-year follow-up, pain at rest on 1-year follow-up, pain requiring treatment on 1-year follow-up, trocar hernia on 1-year follow-up, secondary hemorrhage on 1-year follow-up, blood effusion on 1-year follow-up and infection on 1-year follow-up via McNemar’s test. The results obtained are presented as the concordant and discordant results per matched pair within a 2 × 2 frequency table. Further, the corresponding p values and the odds ratio (OR) estimates for matched samples with 95% confidence interval are included in a forest plot of the results.

Results

Univariate analysis

In total 6533 patients were included in the analysis (Fig. 1), mesh patients composed 19.16% (n = 1252) of the population. The defect sizes in the subgroup of patients with mesh augmentation was with mean 16.3 cm2 [14.54; 18.2] versus 10.8 cm2 [8.7; 12.9] significantly larger compared with the subgroub witout the use of mesh (p < 0.001) (Table 1). Unadjusted comparison of the patient and operation characteristics before matching (Table 2) showed significant differences between mesh vs. non-mesh repair for the preoperative pain, surgical technique, regurgitation, dysphagia, and pain (p < 0.001, each). Table 3 presents the unadjusted analysis of postoperative outcome before matching. After 1 year of follow-up mesh vs. non-mesh patients showed no significant difference in all outcome parameter except pain on exertion which tends to occur more frequently in non-mesh repair (p = 0.072).

Fig. 1
figure 1

Flowchart of patient inclusion

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Table 1 Presentation of ranges and of unadjusted analysis results for homogeneity between mesh and non-mesh hiatoplasty for age and defect size
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Table 2 Unadjusted comparison of mesh versus non-mesh hiatoplasty for patient and operation characteristics before matching
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Table 3 Unadjusted analysis of postoperative outcome comparing mesh versus non-mesh hiatoplasty before matching
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Covariable-adjusted matched pair analysis

Propensity-score matching was performed for 1252 with mesh to 5281 patients without mesh revealing 1207 matched pairs. Figure 2 shows the standardized differences between the matching variables both before (original sample) and after (matched sample) matching.

Fig. 2
figure 2

Standard differences between the matching variables both before (original sample) and after (matched sample) matching

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That difference was well below 10% for all matching variables, attesting to a good balance between the groups for matched pair comparison for those variables. Table 4 demonstrates significant differences between mesh and non-mesh patients after matching. For recurrence there is a significant disadvantage for non-mesh patients. Here, 4.72% of mesh patients and 7.29% of non-mesh patients reported recurrence, when their matched patient reported no recurrence (discordant cases). Additionally in 0.33% both patients of a pair (concordant cases) had a recurrence. This corresponds to a significant deviation (p = 0.012). The same effect can be seen for pain on exertion (8.78% vs 12.10%; p = 0.014, with further 1.08% concordant cases) and pain requiring treatment (6.13% vs 9.11%; p = 0.010, with further 0.99% concordant cases). Regarding all other outcome parameters, no significant differences could be seen between mesh and non-mesh patients (Fig. 3).

Table 4 Outcome parameters between mesh and non-mesh patients after matching (n = 1.207 matched pairs)
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Fig. 3
figure 3

Forest plot—adjusted odds ratios (incl. confidence intervals) for all outcome parameter comparing mesh vs. non-mesh

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Standardized differences for patients with and without follow-up-information

Figure 4 shows the results of the standardized differences for patients with (n = 6.533) and without (n = 3.368) follow-up information. Standardized differences above a value of 10% were found only for age. The patients in the analysis population were on average 3.5 years older. Standardized differences of less than 0.1 were found for all other variables, including the perioperative complication rates, and are thus not suggestive of any bias in patient selection.

Fig. 4
figure 4

Scatter plot of standardized differences between patients with and without follow-up information

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Defect sizes in the matched pair groups

After matching the defect sizes were in both groups with mean 15.9 cm2 comparable (Table 5).

Table 5 Presentation of mean values and ranges for age and defect size for mesh versus non-mesh hiatoplasty after matching
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Types of meshes used in hiatoplasty

A hughe variety of meshes has been used for augmentation of the hiatoplasty (Fig. 5). Beside polypropylene meshes, biological and biosynthetic meshes have been inserted for mesh hiatoplasty.

Fig. 5
figure 5

Distribution of the mesh types for mesh hiatoplasty after matching (n = 1.207 matched pairs)

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Fixation of meshes

The majority of meshes for the augmentation for the hiatoplasty have been fixed with suture, tacks and glue (Table 6).

Table 6 Type of fixation in mesh hiatoplasty in 1.207 patients after matching
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How was the recurrence diagnosed

In the subgroup of patients with non-mesh hiatoplasty n = 92 and in the subgroup of patients with mesh hiatoplasty n = 61 were diagnosed. The diagnosis was confirmed in n = 48 cases (31.4%) by radiology, in n = 106 cases (69.3%) by endoscopy and in n = 28 cases (18.3%) clinically.

Discussion

This is the first large-scale study investigating mesh vs. non-mesh repair in laparoscopic type I hiatal hernia repair with GERD on the bases of data derived from a registry. We could demonstrate that in the subgroup of patients with large defect sizes mesh augmentation of the cruroplasty is associated with a significant lower recurrence rate at 1-year follow-up without increasing the risk of any complications.

Prevention of recurrence after hiatal hernia repair seems of utmost importance, since re-do operations are associated with an increased risk for complications [13]. In type I hiatal hernias there is consensus that sufficient anterior or posterior narrowing of the crura (cruroplasty) should be performed during every type I hiatal hernia repair [6, 14,15,16]. However, it remains controversial if the cruroplasty should be augmented with a mesh [10, 17,18,19,20,21], since the benefits of lower recurrence rates and long-lasting control of GERD symptoms should outweigh the risk of potential mesh-associated complications. In our study we could demonstrate, that using a mesh for augmenting the cruroplasty in the subgroup of patients with larger defect sizes is significantly associated with a reduced risk for recurrence. However, meshes and particularly synthetic meshes are suspect to increase the risk of erosion and fistula formation at the esophageus. Our results show up to 1-year follow-up that the risk for complications was comparable in the mesh and non-mesh group. This underlines the fact, the results from the studies suggesting a higher risk for complications in the mesh group must be interpreted with caution, mostly because only small case series have been published [6, 11, 12]. Furthermore, it must be considered that the mortality of a recurrence repair after failed type I hiatal hernia repair is sevenfold higher compared to the primary repair [22], highlighting the importance of a durable and stable primary repair. In a meta-analysis of RCTs comparing mesh augmentation of the cruroplasty vs. suture cruroplasty it has been shown that the risk for reoperation is significantly lower in the mesh group, while complication rates and operation time was comparably low in both groups [23]. Another meta-analysis revealed comparable results with lower recurrence rates after mesh augmentation of the cruroplasty with no increase in complications, questioning the omnipresent fear of mesh-associated complications [24]. In a risk–benefit-analysis of three RCTs and nine prospective controlled studies with 915 patients it could be demonstrated that the recurrence rate after mesh augmentation is almost halved in a follow-up period of 3 years with a decrease from 20.5% to 12.1% [25]. This reduction in recurrence rate corresponds to an absolute risk reduction of 8.4% or a number needed to treat (NNT) of 12 (95% CI 10.6–13.5). The reduction in recurrence rates appeared even more convincing in a subgroup analysis focusing on studies with a follow-up period of more than 2 years and the use of synthetic meshes. In this group, an life-long absolute risk reduction of 5.6% and an NNT of 18 (95% CI 13.3–27.3) was found with mesh augmentation of the cruroplasty [25]. The mesh-associated complications were rare (1.9%) and did not lead to a higher procedure-related complication rate or more overall complications of the procedure, which again contradicts arguments against the routine use of mesh augmentation in hiatal hernia surgery [25]. With our data we can only bring up arguments for the selective use of mesh augmentation of the cruroplasty in type I hiatal hernias with larger defects.

In our study population the risk of intra-, peri- and postoperative complications, secondary hemorrhage or blood effusion was not increased by using a synthetic mesh to reinforce the cruroplasty, which indicates that mesh-related complications seems to be not so frequent. In contrast, the non-mesh group with larger defect sizes had a significantly higher risk for recurrence, underlining the possible role of mesh augmentation in the prevention of a potential reoperation. Also, pain at rest and pain requiring treatment were significantly more frequent among the non-mesh group. Therewith, our findings may have some clinical implications. Pain following laparoscopic anti-reflux surgery occurs in over 20% of patients The preoperative consenting process in type I hiatal hernia patients specifically with larger defect sizes should include all arguments for and against mesh augmentation for the necessary cruroplasty. In younger patients, who may live long enough to experience a potential recurrence, a mesh augmentation of the cruroplasty should be discussed. In case the patients decline the use of mesh, the known risk of complications of a potential reoperation needs to be addressed and explained.

The large number of cases in registries are eminently suited to comparative studies since no patients are excluded due to strict criteria for clinical trial (high external validity) and, further potential influence factors on the outcome are also considered. However, since this is a registry-based study, there are some limitations.

There may also be some selection bias since choice of operative technique may depend on the surgeon’s expertise and different reimbursement for each surgical technique. Also, the health care systems of the countries recording their patients in the Herniamed Registry (e.g., Germany, Austria, Switzerland) may have specific limitations and biases regarding surgical treatment of hiatal hernias. However, in the Herniamed Registry these limitations are well-controlled and the following measurements are utilized to limit biases, limitations and incorrect or missing data, which could diminish generalizability of findings: signed contract with the responsible surgeon on each participating hospital for data correctness and completeness, display of missing data by the software, review of the perioperative outcome on 1-year follow-up and control of the data entry by experts as part of the certification process of hernia centers. The best safeguard is to match the data against other administrative data, literature or other registries [26]. Also, patient reported outcomes (PRO) as part of the follow-up process in the Herniamed registry are increasingly used [27, 28], adding value to the clinical evaluation and increasing patient satisfaction [29].

Since 1-year follow-up information is not available for one third of patients, it is necessary to rule out selection bias. On analysis of the standardized differences for patients with and without follow-up, values of 0.1 were routinely found, also for the perioperative complication rates, which argue against selection bias.

In conclusion, we could demonstrate that mesh augmentation of the cruroplasty during type I hiatal hernia repair with larger defect sizes is significantly associated with decreased rates of hernia recurrence, pain on exertion and pain requiring treatment.