Early postoperative outcomes in a retrospective propensity score-matched comparison of robotic extended totally extraperitoneal (r-eTEP) and extended totally extraperitoneal (eTEP) repair for ventral hernia

Ventral hernias, defined as a protrusion of abdominal content through a defect in the fascia of the abdominal wall [1] encompassing congenital and acquired defects, are a common condition associated with significant patient morbidity, including paint, incarceration, and recurrence [2‐6].

Ventral hernia repair (VHR) is one of the most frequently performed procedures in the United States, with over 350,000 operations annually [7]. Various techniques for VHR exist, ranging from open procedures with or without mesh placement [8] to minimally invasive approaches such as laparoscopic and robotic-assisted techniques.

Minimally invasive methods have demonstrated lower complication rates, shorter hospital stays, lower treatment costs and a reduced risk of recurrence compared to open repair [9‐12]. Among these, robotic surgery offers additional benefits including enhanced precision and ergonomics [13, 14].

The extended totally extraperitoneal repair (eTEP), initially introduced for inguinal hernia repair, has been adapted for ventral and incisional hernias, yielding promising results such as low complication rates, reduced postoperative pain and shorter hospital stay [15‐18]. Compared to other minimally invasive methods (i.e. intraperitoneal onlay mesh) eTEP is associated with lower odds of hernia recurrence and a lower risk of surgical site infection (SSI) as demonstrated in multiple meta-analysis and systematic reviews [19].

Robotic eTEP (r-eTEP) combines the advantages of robotic platforms with the benefits of eTEP, allowing for precise, minimally invasive placement of the retromuscular mesh. Furthermore it can be combined with a transversus abdominis release (TAR) [20, 21]. TAR is one of the only techniques allowing primary closure of large defects while simultaneously maintaining retromuscular mesh placement. This is of utmost importance as primary fascial closure is associated with a lower hernia recurrence [22]. Compared with laparoscopic ventral hernia repair (lapVHR), robot-assisted ventral hernia repair (rVHR) shows improved results with a shorter hospital length of stay, lower reoperation rate, fewer conversions to laparotomy and comparable complication and recurrence rates [23‐27], although concerns remain regarding longer operative times and higher costs [25, 28].

The comparison between eTEP and r-eTEP is important to understand the advantages and disadvantages of each technique and to make evidence-based recommendations for the selection of the optimal surgical method. In addition, due to the newly introduced technique and the limited number of studies on this topic, further studies are needed. To date, only a limited number of studies have analysed r-eTEP, and to our knowledge, only one study has compared eTEP and r-eTEP [20, 21, 29‐31]. In their comparison of both techniques, Lu et al. reported that r-eTEP is used more frequently in patients with more complex abdominal wall defects and has similar perioperative outcomes, such as length of stay and reoperation rates, but with significantly longer operating times and higher hospital costs [32]. However, propensity score matching (PSM) was not conducted, limiting the ability to balance group characteristics for accurate outcome comparisons.

The purpose of this study is to present and provide a comprehensive analysis of early postoperative results of r-eTEP and compare operative outcomes between r-eTEP and laparoscopic eTEP through a propensity score matched analysis.

Minimally invasive techniques such as eTEP and r-eTEP have demonstrated better intraoperative and postoperative results compared to open approaches [9, 10]. r-eTEP repair is a relatively new surgical approach and has shown potential advantages over eTEP in studies conducted thus far [23‐26]. However, concerns about longer operative times and higher healthcare costs remain [28]. The number of studies on this topic is limited, and additional studies are therefore needed.

This study aimed to compare the outcomes of eTEP and r-eTEP techniques while addressing gaps in the existing literature, thus providing further evidence for potential treatment strategies.

Preoperative patient characteristics, especially BMI and ASA scores, did not show significant differences between the two groups, unlike other studies that observed significant differences or described higher BMI and ASA scores [31, 32]. However, in our study, the patient data were matched via propensity score matching (PSM) to minimize differences and enable more precise analyses, thus minimizing bias.

A comprehensive analysis of hernia characteristics demonstrated that M3 and M4 hernias according to the EHS classification were significantly more frequently operated on using the r-eTEP technique (M3 p-value: 0.006; M4 p-value: 0.020). Incisional hernias and hernias with rectus diastasis were also significantly more common in the r-eTEP group. This finding suggest that the r-eTEP technique may be preferable for more managing complex hernias. This aligns with previous studies that noted r-eTEP was used for more challenging cases [32]. This highlights the advantages of the robotic platform, including its precision and ergonomic benefits [38].

In the eTEP group, the median defect size was 6 cm² and the median mesh size required was 375 cm², compared to the r-eTEP group, which had a median defect size of 16 cm² and a median mesh size of 420 cm² (p-value = 0.015). These significant differences further support the hypothesis that r-eTEP is better suited for larger and more complex hernia defects, requiring more extensive closures. This is consistent with findings by Lu et al., who also reported a preference for robotic procedures in such cases [32].

The median operation time in this study was 131 min for eTEP and 117 min in r-eTEP, with no statistically significant difference. However, these results contrast with prior studies, which reported longer operative times for robotic techniques [28, 32]. Compared with our results, longer operation times have been reported for the TEP technique, with durations of 168 and 218.9 min, as well as for the r-TEP technique, with a duration of 162.2 min [16, 18, 31]. The shorter operation times observed in this study may reflect the expertise of a single surgeon performing all procedures. The shorter operative times observed in this study may reflect the expertise of a single experienced surgeon performing all procedures. While this ensured consistency and a fair comparison between the two techniques, it also limits the generalizability of the findings, as these results may not be easily replicated by surgeons with varying levels of experience Our results also highlight the benefits of robotics, indicating shorter operative times in r-eTEP than in laparoscopic eTEP, although not significantly. Further studies are needed to validate these trends and evaluate how robotic systems can reduce operative times as their usage becomes more routine [39].

The overall intraoperative complication rate was low in both groups with no significant difference (4.4% for eTEP versus 0% for r-eTEP). However, these complications were not severe and did not require conversion to an open procedure. These findings align with other studies that reported similar results. Belansky et al. reported a relatively low intraoperative complication rate of 2.5% since the introduction of eTEP for ventral hernia repair [16]. Similarly, a meta-analysis reported an intraoperative complication rate of 2% [19]. According to Belyansky et al., no intraoperative complications were described in the r-eTEP group [31]. The low complication rate in both groups confirms the safety and feasibility of the eTEP and r-eTEP techniques, with r-eTEP possibly having an additional safety advantage but without a statistically significant result.

Drains were used more frequently in the r-eTEP group than in the eTEP group. The increased use of the r-eTEP method for complexity of hernias treated with r-eTEP. The decision to place a drain was primarily influenced by intraoperative findings, such as a tendency to bleed, or by the presence of specific risk factors, including therapeutic anticoagulation or diabetes. The size of the hernia defect, however, did not play a role in the decision making process. The higher frequency of drain placement in the r-eTEP may have contributed to the slightly higher incidence of postoperative pain observed with r-eTEP, although the difference was not statistically significant.

The median postoperative hospital stay for robotic eTEP was 2 days (range:2–2), which was significantly shorter than that for laparoscopic eTEP at 3 (range:2–3.5) days (p value < 0.001). These results indicate a faster recovery and earlier discharge of patients with the r-eTEP technique Possible explanations for this observation include the enhanced precision and ergonomics of the robotic platform, which may reduce tissue trauma and postoperative discomfort, thereby promoting a faster recovery. This result was observed in the meta-analysis by Peñafiel et al., where the hospital stay was significantly shorter for robotic-assisted compared with laparoscopic repair, with a mean difference of − 1.05 days [40]. In the study conducted by Lu, no relevant difference was observed, with the overall length of stay being low for both techniques (0.2 days for eTEP vs. 0.1 days for r-eTEP) [32]. In other studies, the mean length of stay for r-eTEP was 0.7 days, which was lower than that reported in our study [31, 41]. This difference could reflect variations in practice, with some studies possibly performing these operations on an outpatient basis, while in our department in Germany, we routinely perform inpatient monitoring post-procedure. For instance, in the study by Bauer et al. in Germany, patients stayed in the hospital for an average of 3 days following r-eTEP, which aligns closely with our findings [20]. This suggests that the postoperative length of stay can vary based on country-specific protocols and clinical practices. Further research is required to explore these factors more comprehensively and gain a deeper understanding of the mechanisms underlying this variation.

Our results showed a similar postoperative complication rate within the first 30 days in the eTEP and in the r-eTEP group (13.3%). Similarly, surgical site-specific complications rates, such as SSO and SSI rates, were comparable between the two groups. The only instance of blood transfusion in the laparoscopic group was due to postoperative arterial bleeding at the trocar site in the left lower abdomen. This complication was swiftly addressed at the bedside with suturing. The patient had no known risk factors that could have contributed to the bleeding. In other studies comparing both techniques Lu et al. reported a complication rate of 9.2% for eTEP and 2.3% for r-eTEP [32]. Other studies on r-eTEP also reported a complication rate between 4.9% and 5.4% [20, 31]. Compared with these studies, the postoperative complication rates were comparable. However, this could be influenced by the exclusion procedure and propensity score matching, which allow a better comparison between the two groups and thus increase the validity of our results. In our dataset, 51 patients were excluded from the eTEP group and seven patients from the r-eTEP group had no postoperative complications. Therefore, the observed difference compared to other studies should be interpreted with caution. A direct comparison between the two groups regarding postoperative complications, especially SSO or seroma, is difficult in our case because drains were used significantly more often in the r-eTEP group. This could influence the risk of seroma formation and the validity of the comparison. Further investigations and larger multicenter studies are needed to determine the reasons for these differences.

The findings of the present study show that the r-eTEP technique may offer potential benefits. In particular, for the repair of more complex hernias such as large hernia defects, incisional hernias, and hernias with rectus diastasis, the r-eTEP technique was more frequently used and has been demonstrated to be the preferred method in this cohort. R-eTEP had a significantly shorter hospital stay compared to e-TEP while intraoperative and postoperative complications were comparable in both groups. However, randomised-controlled studies are necessary to address this potential benefits.