IPOM versus eTEP as minimally invasive approaches for ventral/incisional hernias: a systematic review and meta-analysis

Abdominal wall ventral hernias constitute a significant workload for the surgeon, with over 300,000 repaired annually in both Europe and the United States, and are responsible for an economic burden of 3.2 billion dollars each year [1]. They consist of primary (umbilical, paraumbilical, epigastric and Spigelian), incisional and parastomal hernias. Despite an improved understanding in closure techniques (i.e. optimal suture-to-wound length ratio) and biomechanics [2, 3], incisional hernias remain a common complication after abdominal surgery, with a reported incidence as high as 60% in high-risk cohorts [4, 5]. Primary ventral hernias, on the other hand, occur spontaneously and affect 20% of the healthy adult population [6]. Whilst they can simply be aesthetically displeasing, they can also cause discomfort, pain and worse still, result in incarceration of abdominal contents, necessitating emergency interventions.

Ventral hernia mesh repair techniques have rapidly evolved over the last two decades. Whilst it is generally accepted that laparoscopic repair is superior to open repair in terms of seroma formation, length of hospital stay and recurrence, it can also result in complications [7‐9]. The traditional laparoscopic technique involved reduction of the hernial sac and bridging the defect with an intraperitoneal prosthesis without defect closure (IPOM) [10]. However, increased short-term postoperative pain (due to the use of tackers) [11] and early recurrence (due to mesh migration) [12] have led to the development of alternative techniques, such as enhanced-view totally extraperitoneal (eTEP) repair [13], whereby a prosthesis is laid out flat in the dissected retromuscular space, without the need for mesh fixation.

We aimed to compare short- and long-term outcomes between minimally invasive IPOM and eTEP techniques for ventral hernias in this current meta-analysis.

This systemic review and meta-analysis was conducted in accordance with the Cochrane Handbook of Systematic Review & Meta-Analysis of interventions (v6.2) principles and reported according to the Preferred Reporting Items for Systemic Review and Meta-Analyses (PRISMA) [14] and Assessing the Methodological Quality of Systematic Reviews (AMSTAR 2) [15] guidelines. It was registered in the PROSPERO database (CRD42024534570).

The current systematic review and meta-analysis, encompassing 12 studies and 868 patients, demonstrates significantly more pain at postoperative day 7 as well as longer hospital stay in the IPOM(+) group but no differences in complications or recurrence between the two groups. However, these findings have to be interpreted with caution given that the majority of included studies were observational with a short follow-up (longest duration was 28 months in eTEP group in Bellido Luque et al.) [21] and have likely underestimated the true recurrence rate. A robotic (versus a laparoscopic) platform was utilized in two of the studies [23, 28] and the resultant improved ergonomics may have influenced the operative time. Although the majority of hernias operated on across the 12 studies comprised primary ventral hernias, there is now substantial evidence in the literature demonstrating similar safety and efficacy when eTEP is used to repair incisional hernias [32, 33]. It is important to highlight that most hernias were midline hernias in the current meta-analysis and their defects were medium in size at an average of 36 cm². However, eTEP has been shown to be an effective treatment strategy in the repair of subcostal incisional hernias, with lower postoperative pain and shorter hospital stay compared to traditional IPOM +  [33]. Five of the 12 studies described simultaneous TAR with eTEP, performed for bigger defects and/or lateral hernias [22‐24, 27, 28] (see Table 1).

Open ventral hernia mesh repair techniques are historically associated with high recurrence rates, ranging from 12 to 52% [34, 35] and hence have been largely superseded by the laparoscopic approach. One of the largest series of laparoscopic IPOM published in 2003, whereby a bridging onlay mesh was inserted without defect closure, demonstrated a recurrence rate of only 4.7% after a mean follow-up of 20.2 months [34]. However, it also had a moderately high postoperative complication rate of 13.2%. Subsequently, Franklin Jr et al., in his series of 384 patients treated with laparoscopic IPOM + with a mean follow-up of 47.1 months, showed that the recurrence rate could be further reduced to 2.9% following defect closure, with an acceptable complication rate (10.1%) [36]. However, defect closure during laparoscopic IPOM is not universally performed as it is technically challenging. In the current meta-analysis, 4 out of 12 studies [24, 29‐31] did not close the defect. However, data from all twelve studies were pooled together to generate summative outcomes in the overall analysis. Notwithstanding this, we have performed subgroup analyses comparing IPOM with defect closure (IPOM +) with eTEP and demonstrated that similar findings prevailed, particularly with regards to recurrence (2.7% IPOM + vs. 1.8% eTEP; p = 0.65).

Laparoscopic IPOM, although superior to open repair in terms of faster recovery and return to work and lower wound and mesh complication rates, is not without its pitfalls. Indeed it is associated with poor cosmesis due to skin bulging over the defect, weakness over the bridged gap, mesh eventration as well intraperitoneal bowel adhesions to the mesh [9, 11, 37]. In addition, some patients could experience a certain degree of lack of core support and functional stability when the defect is not closed but simply bridged with a prosthesis [38]. Defect closure, whilst technically cumbersome, may provide a more uniform scaffolding that allows mesh ingrowth and reduce the risk of mesh eventration and skin bulging and seroma formation [37, 39, 40]. However, detractors of defect closure argue that it may convert a tension-free into a tension repair and hence increase the risk of recurrence. A recent meta-analysis by Tryliskyy et al. [41]. evaluating IPOM versus IPOM + failed to demonstrate any significant difference between the two techniques when recurrence and major complications were grouped together as a composite outcome. However, the latter study was limited by the inclusion of merely 3 RCTs with divergent hernia and operative characteristics. Further research is warranted to determine if defect closure in IPOM translates into superior patient outcomes.

Enhanced-view extraperitoneal repair (eTEP), on the other hand, involves dissection in the retromuscular/extraperitoneal plane and obviates the need for mesh fixation as the mesh is sandwiched in between the rectus abdominis muscle anteriorly and the rectus sheath posteriorly [37, 42, 43], hence becoming the favoured approach for some surgeons. Due to the more extensive dissection required (as well as the need for transversus abdominis muscle release in cases of large defects), eTEP is associated with longer operative times, as evidenced in the current study. However, no other significant differences were observed between the two techniques. The longer operative times could translate into increased costs but the latter are offset by the use of a simple polypropylene mesh (versus a composite mesh) in cases of eTEP.

Enhanced-view totally extraperitoneal repair requires a sound understanding of abdominal wall anatomy and has a steep learning curve. A 2022 meta-analysis revealed a 2% incidence of intraoperative complications and a 1% incidence of major complications [44]. These include inadvertent puncture of the posterior rectus sheath resulting in pneumoperitoneum, hollow viscus injury, retrorectus haematomas/seromas, damage to epigastric vessels or neurovascular bundles (especially during transversus abdominis release), internal (or interparietal) hernia secondary to dehiscence of the re-approximated posterior sheath, injury to the linea alba during the midline cross-over (resulting in early hernia recurrence) as well as areas of ecchymosis on the abdominal wall (possibly from vascular injury or muscle shearing during anterior sheath closure) [42, 45‐47]. With regards to contraindications, eTEP may not be possible in cases with an extensive (from xiphoid to pubis) prior midline incision, as the preperitoneal space would have been violated, rendering the midline cross-over risky if not impossible [47].

Our current analysis has some limitations. Firstly, most of the data originate from observational studies, with their inherent biases as well as short follow-ups. Recurrence rates could be different if patients were followed up for longer. Secondly, whilst most studies employed laparoscopic techniques, two (of twelve) [23, 28] utilized a robotic platform but the data were analysed together in the statistical analysis. Finally, we cannot comment on costs or patient-reported outcome measures (such as core strength and cosmesis) as these were not uniformly reported. Nonetheless, our findings demonstrate that IPOM (+) is as effective as eTEP for ventral hernias in the short-term and both have an acceptable safety profile. It is perhaps prudent to reiterate that ‘not one size fits all’ when it comes to ventral hernias and that some cases may be better served with an IPOM (+) [defect sizes ranging from 2 to 6 cm] and others, eTEP [defect sizes 5–12 cm, ± rectus diastasis] and others, still an open primary/suture repair (< 2 cm defect).