Due to previous mesh placement, potential peritoneal adhesion, and disturbed anatomical planes, the repair of recurrent incisional hernia poses a technical challenge. As a result, the recurrence rates and complication risks are higher for recurrent hernia [14], and previous incisional hernia repair is classified as a complex abdominal wall hernia [15].
The results of a large cohort study showed that the cumulative 5-year recurrence rate of incisional hernia after initial repair was 12.3%, increased to 23.8% after the second repair, 35.3% after the third, and 38.7% after the fourth repair [16]. The use of prostheses has greatly improved the outcomes of ventral and incisional hernia repairs in terms of recurrence, and the use of mesh-based surgical techniques is consistently recommended in the guidelines [17–20, 4]. However, the recurrence rate after incisional hernia repair remains high during the long-term follow-up period. The Danish hernia registry study reported that the cumulative risk of reoperation at 5 years after elective incisional hernia repair was 12.3% for open mesh repair, 10.6% for laparoscopic mesh repair, and 17.1% for non-mesh repair [21]. Moreover, it has been suggested that the recurrence rates are likely even higher in real-world circumstances; thus, surgeons call for a follow-up of at least 10 years [2]. A considerable number of recurrent incisional hernias require reoperation. Nearly 20% of all incisional hernias treated in our institution during 5 years were recurrent incisional hernias, and the proportion was consistent with that of previous reports [1, 22, 23]. This suggests that selection of the appropriate surgical strategies for recurrent incisional hernia repair is of utmost clinical and socioeconomic importance.
In the literature, there is a lack of comparison between open and laparoscopic techniques for outcomes following recurrent incisional hernia repair. For laparoscopic repair, single-arm studies of case series reported a mean operative time of 147 minutes [12], and overall postoperative complication rate between 11.5% and 13%, and a recurrence rate between 3.1 and 5.7% among cohorts with fewer than 100 patients during an intermediate mean follow-up period of 30 to 41 months [12, 23]. For open repair, Berry et al. presented a case series of 47 recurrent incisional hernias with open sublay repair. Wound-related complications occurred in 12 patients (25.5%), and four (8%) developed re-recurrences after a mean of 20 months of follow-up [24]. Another recent large prospective study comparing the outcomes of 896 initial vs. 798 recurrent open ventral hernias in a tertiary hernia center reported that patients with recurrent ventral hernia had older age, more comorbidities, and a larger hernia defect. Intraoperative CST was performed in 39.5% of recurrent ventral hernias. The overall recurrence rate of recurrent ventral hernias was 4.7% at a mean of 27.6 ± 37.4 months of follow-up. The most common postoperative complications were seromas (17.8% of 798 patients who had recurrent ventral hernia repairs), wound infection (8.9%), wound-related reoperations (5.0%), hematomas (3.5%), and mesh infection (2.1%) [25].
To date, there is still no guideline or recommendation regarding the optimal approach for recurrent abdominal wall hernia management. In this retrospective study, 292 patients with recurrent incisional hernias were included. To our knowledge, this is one of the largest studies focusing on this topic. The results from our study in terms of postoperative complications and recurrence rates in the subgroups are consistent with those reported by previous studies. Furthermore, our study also investigated the influence of hernia defect size or related techniques on the outcomes, which had been insufficiently addressed in previous studies. Since the imbalance in patient characteristics among the four subgroups, we offered a focus on the comparisons between Group I (open sublay repair without CST) and Group III (IPOM), Group II (open sublay repair with CST) and Group IV (hybrid techniques).
Surgeries without additional approaches: open sublay repair vs. IPOM
In the present study, the minimally invasive IPOM technique for recurrent incisional hernia was associated with a significant reduction in operative time and length of hospital stay compared to open sublay mesh repair without CST for largely equivalent patient cohorts. Additionally, the recurrence rates were similar between the two groups. These findings are consistent with the results from previous studies comparing laparoscopic and open incisional ventral hernia repair [26–28]. Some studies indicated that open hernioplasties were associated with higher risk of postoperative complications, particularly wound infections, compared to laparoscopic approaches. However, this difference was not significant in our research, when comparing open sublay repair without CST and laparoscopic IPOM only. Of note, a slightly higher BMI and less mesh repair history were found in the laparoscopic IPOM group compared to the open sublay repair group. This suggests that patient selection may plays a role when comparing outcomes between the two operations. In those patients with small to medium size defects, higher BMI may be more likely to benefit from the laparoscopic IPOM. While the history of mesh repair, especially intraabdominal mesh repair history, may have a negative impact on the choice of pure laparoscopic IPOM for reoperation of recurrent incisional hernia.
Additional techniques: CST vs. hybrid techniques
For similar patient cohorts, the outcomes between open sublay repair with CST and hybrid procedures were comparable except for a difference in the incidence of pulmonary embolus/DVT. The reason for the higher incidence of thrombosis in the hybrid technique group remains unclear, but may be correlated with hemodynamic changes in the venous system during repeat pneumoperitoneum establishment. In addition, we also observed that patients in the open sublay with CST group may have a slightly but not significantly higher incidence of seroma than those in the hybrid technique group. This observation may be the consequence of more extensive dissection for the CST.
Anterior CST vs. posterior CST-TAR
Compared with posterior CST-TAR, anterior CST was associated with more wound morbidities caused by perforator vessel injury. In our study, there were 42 cases of anterior CST and eight cases of posterior CST-TAR. Four cases of wound infection and one recurrence were observed after anterior CST, while none was reported after TAR. However, these differences were not significant. A recent study showed that open anterior CST with perforator vessels preserving was comparable to TAR and had equally acceptable outcomes for complex hernias, in terms of surgical site infection and surgical site occurrence rates, recurrence rates, and quality of life [8].
Open or laparoscopic approaches alone vs. additional techniques
Despite differences among the four groups in terms of BMI, previous meshes placed, hernia defect size, mesh size, and mesh excision, there was no significant difference in hernia recurrence rates in our study. The rates of overall complications after open sublay repair without CST and laparoscopic IPOM were lower than those after open sublay repair with CST and the hybrid procedure. The rates of major complications were also significantly lower after laparoscopic IPOM and open sublay repair without CST compared to those after open sublay repair with CST and the hybrid procedure. However, these results should be interpreted with caution because of the risk of selection bias. The reason why the patients who underwent CST or hybrid techniques had compromised outcomes may be the increased complexity of the case. Neither CST nor the hybrid technique can be considered routine surgical techniques for “simple” incisional hernia. In most cases, they were performed for “complex” cases, with larger hernia defects, significant loss of domain, or multiple recurrences. Further, additional dissection and adhesiolysis following prior abdominal wall hernia repair may increase the operation time and introduce extra injuries to tissues, which may lead to higher rates of intraoperative and postoperative complications (surgical site infection, seroma, bleeding, etc.), particularly iatrogenic enterotomies and other organ injuries [1, 8, 27].
Stratified analysis by the EHS width
When comparing patients with different defect widths (W1, W2, and W3), we found that recurrent incisional hernias with higher EHS width classes required larger meshes and a greater proportion of open sublay with CST and the hybrid procedure. They also involved longer operation time, longer hospital stays, higher complication rates, and slightly but not significantly higher recurrence rates. This finding further confirms that larger hernia defects play a role in procedure selection and clinical outcomes for patients with recurrent incisional hernia.
Of Note, the calculated mesh/defect ratio in W3 were much less compared to W1 and W2, similarly, in Group I and Group II compared to Group II and Group IV. It may cause concern that the forces resisting mesh displacement in these groups (W3, Group II and Group IV) are much weaker. However, the mesh/defect ratio was initially applied in a mesh bridging repair. The actual risk of mesh displacement may be overestimated, especially in the patient with larger defect, since the fascial defect was closed before mesh placement in our study. These advanced techniques for defect closure in “complex” cases, in a sort of way, “saved” the size of mesh required.
Tailored strategy
Several hernia features may influence the selection of the appropriate surgical approach for a recurrent incisional hernia, including defect size and location, type of recurrence, intraabdominal adhesions, number of previous repairs, prior repairs with or without meshes, etc. We hypothesize that no single approach is suitable for all patients with recurrent incisional hernia, and a tailored procedure can be used to achieve optimal outcomes.
For small, simple recurrent incisional hernia with a low risk of inferior prognosis, either laparoscopic IPOM or open sublay repair can be selected. Laparoscopic surgery may be more cost-effective due to the shorter operative time and length of hospital stay. Additionally, patients with higher BMI or less intraabdominal mesh history may be more likely to benefit from laparoscopic repair. Another possible advantage of laparoscopic surgery is that it can more entirely explore the incisional scar and identify occult incisional hernias. However, it should be kept in mind that an expensive special mesh and fixation device are used either in laparoscopic IPOM or in the hybrid procedure. Also, a high risk of intraabdominal adhesions and long-term complications like ileus after laparoscopic IPOM remains a concern and seems non-negligible according to the literature [4]. These are some of the reasons that the proportion of laparoscopic IPOM technique in our institution was decreasing year by year, from 55.6% in 2015 to 40.8% in 2019. Recent studies have yielded promising results when several new minimal invasive repair techniques were used for small and mid-sized primary and secondary ventral hernias, including the mini/less open sublay technique (MILOS) [29], endoscopic MILOS (EMILOS) [30], and enhanced-view totally extraperitoneal (eTEP) technique [31]. However, the evidence is still inadequate for definite conclusions.
“Complex” recurrent incisional hernias often require repair with wide hernia defect closure, extensive dissection, and larger mesh placement. Both sublay repair with CST and the hybrid procedure, which have equivalent postoperative complication and recurrence rates, are reliable techniques. Furthermore, the TAR procedure was increasing for complex hernias in our hospital in the later years of our study period. And for individuals with recurrent incisional hernias, the retro-muscular and lateral preperitoneal planes often remain minimally violated despite multiple repairs [32]. The progress of minimally invasive technology has further innovated the CST, including the endoscopic anterior CST, the laparoscopic TAR, and the robotic TAR [33, 34]. Less postoperative complications were reported after these minimally invasive CST.
Risk factors of postoperative complications
In the present study, longer operative time, higher BMI, and smoking were identified as risk factors, and are well known to influence the risk of complications following hernia repair. Of note, one risk factor we found for the complications was a larger hernia defect size (EHS width W3 ≥ 10 cm), which has also been reported in previous studies [21, 23, 35]. From a clinical standpoint, larger hernia size means more extensive dissection, more difficulties in closure of the defect and larger meshes placed. These factors can explain why larger hernias are associated with a higher risk of postoperative complications. On the other hand, the EHS width classification of recurrent incisional hernias could be easily used to predict poorer prognosis. Interestingly, the highly suspected factors, including multiple repair history, usage of mesh in previous repair and mesh removal in reoperation, were not significant for predicting complications.
Limitations
Our study includes a rather large population with repair surgeries performed by a few surgeons from the same team with a standardized protocol, which reflects what most surgeons practice for this specific condition. However, the study has several limitations. Firstly, since this was an observational study, the data was collected retrospectively from a single institution. There might be information bias from the surgeons’ choice of procedures and from imbalance in patient characteristics among the groups. Recurrent incisional hernia is a complex clinical issue, as it involves hernia defect size, hernia location, previous mesh placement and previous procedure. Therefore, it is difficult to control the baseline of all patients’ characteristics. Secondly, data concerning postoperative pain [3] and other patient-reported outcome measures were insufficient. Lastly, there was a lack of long-term follow-up outcomes. However, the present study reflects the clinical practice in our institution.