Incisional hernias are an increasingly common complication encountered by surgeons and their patients, as survival rates from major abdominal surgery continue to improve. The incidence of incisional hernia after midline laparotomy is estimated to be 9%–20% after 1 year [1], resulting in approximately 8000 UK repairs annually [2]. While patient factors such as obesity, smoking and diabetes certainly contribute, excessive suture tension during the critical wound healing period causes local ischaemia at the suture-tissue interface and may initiate incisional hernia [3]. Subsequent suture “cheese-wiring” through fascia creates small linear defects that enlarge over time with repeated abdominal wall straining. The clinical and economic implications of incisional hernia have precipitated preventative research, including Jenkins rule [4], small-bite closure [5], and prophylactic mesh implantation [6] which are discussed in recent high-profile international guidelines [7, 8]. However, many surgeons continue to adopt suture closure over prophylactic planar mesh since this prolongs surgery and risks infection in a contaminated field.

Dumanian, a general surgeon with specialty training in plastic surgery, recently created a novel mesh suture (Duramesh™) intended to solve the biomechanical problem of suture pull-through, and was approved for humans, May 2021 and September 2022 in the EU/UK and US respectively. Duramesh™ (Figure 1) is a cylindrical latticework of polypropylene filaments attached to the swage-end of a standard curved needle which, upon tying, flattens out, emulating a ribbon of planar mesh, thereby distributing tension at the suture-tissue interface and allowing fibrovascular ingrowth around individual filaments to strengthen repair [9]. Preclinical studies have shown that Duramesh™ requires greater ultimate tensile strength and maximal force to cause suture pull-through, compared to 0-polyprolyene suture [9, 10]. Proponents of Duramesh™ report that it combines the simplicity and speed of suture closure while simultaneously reducing hernia occurrence and surgical site infection (SSI) typically seen with prophylactic mesh [6].

Mesh strips were the first iteration of mesh suture, consisting of planar mesh cut into 2 cm strips and tied like conventional suture to achieve tissue apposition. Animal models found improved resistance to pull-through and incisional hernia formation [11, 12], and several subsequent studies demonstrated safety in human primary umbilical hernia repair [13], contaminated incisional hernia repair [14], and repair of large abdominal wall defects [15]. Recognising growing enthusiasm amongst the abdominal wall community, we performed a scoping literature search that suggested the current evidence base for mesh suture and strips typically cites case-series, reporting relatively few patients; we decided to investigate this further via systematic review. At the time of writing, we believe this is the first systematic review of mesh suture and mesh strips for abdominal wall closure and ventral hernia repair.

The search identified 778 references. After removing 43 duplicates, the title and abstract of 735 studies were screened and 701 excluded. 34 manuscripts were examined in full of which six were suitable for inclusion [13–15, 22–24]. Five were retrospective case series (four single surgeon series [13–15, 22], one pooled database of multiple surgeons [24]), and one was an interim report from an ongoing randomised controlled trial [22]. Our PRISMA flow diagram is shown in Figure 2. In total, there were 585 patients reported of which 553 (95%) underwent mesh suture or mesh strip repair, and 32 patients underwent conventional suture repair during open surgery. There were no studies investigating laparoscopic or robotic trocar site closure. Meta-analysis was therefore not conducted due to heterogeneity of participants and low number of participants undergoing conventional suture repair.

The most important long-term surgical complication after failed closure of midline laparotomy or ventral hernia repair is occurrence or recurrence of incisional hernia, which can reduce quality of life significantly. Our systematic review assessed incisional hernia occurrence after repair with the novel mesh suture, Duramesh™, or its mesh strip precursor.

The mechanism behind mesh suture/strips is thought to be attributable to physics and the concept of suture pull-through. By definition, pressure equals force divided by surface area, so when tissue edges are approximated, local pressure at the suture-tissue interface is determined by outward force (rectus contraction and intraabdominal pressure) and the surface area of contact [25]. Mesh suture/strips are thought to reduce the likelihood of chronic “cheese-wiring” due to broader surface area of contact and enhanced tension distribution, therefore resisting fascial dehiscence and development of subsequent incisional hernia [9]. In an experimental study, Cengiz et al. demonstrated that smaller tissue bites increased wound strength by lowering the tension on individual stitches [26]. The principle underlying Duramesh™ is similar to the “small-bite closure” method and mesh repair of incisional hernia, as these techniques aim to distribute tension evenly along closed fascial edges. Furthermore, the 3D macroporous structure of Duramesh™, akin to other permanent mesh prostheses, has demonstrated greater tissue integration in in-vivo studies, suggesting an additional tissue response around a mesh scaffold via a permanent foreign body scar response [11, 27].

We found considerable study heterogeneity, poor study quality and critical risk of bias in this systematic review. Direct comparison of incisional hernia occurrence with selected articles from available high-quality literature was not possible due to heterogeneity in reporting follow-up, with a range of short to medium-term follow-up observed. However, incisional hernia occurrence with mesh suture/strips did appear lower than known published estimates. The STITCH trial revealed an incisional hernia rate of 13% at 1 year (n = 268, 9%–18% 95% CI) for the “small bite” group after midline laparotomy [28], and rates were 13% and 18% at 2 years (n = 188, 8%–18% 95% CI; n = 185, 13%–24% 95% CI) in the prophylactic onlay and sublay mesh groups of the PRIMA trial, respectively [6]. Other historic figures include a 21% recurrence rate at 21 months median follow-up (n = 3258) from the Danish registry study [29], and 18% at 1 year (n = 84, 10%–28% 95% CI) after primary mesh repair from Luijendijk et al’s landmark trial of mesh versus suture repair of incisional hernia [30]. The patient cohorts from these studies had largely similar characteristics (mean age, mean BMI, diabetics, smokers) to those found in this systematic review, excepting patients in the PRIMA trial who underwent elective abdominal aortic aneurysm repair and were thus increasingly prone to incisional hernia development due to associated connective tissue disease.

The STITCH [28] and PRIMA trials [6] were sufficiently important to achieve Lancet publication and have impacted the way surgeons perform closure of the abdominal wall following primary laparotomy. Notably, both studies involved other surgical specialties including gynaecology, urology and vascular surgery. Rates of incisional hernia amongst participating institutions in the STITCH trial [28] were varied (0%–25%) possibly reflecting differences in abdominal closure expertise and patient case mix rather than suture technique alone. Learning curve was also difficult to measure and may not have been accounted for. Conversely, in this systematic review of mesh suture/strips, general surgeons with an abdominal wall interest were performing closure which may explain the low incisional hernia rates observed compared to STITCH. Another common criticism of STITCH [28] is whether the use of a 31 mm needle (2/0 PDS) in the small bite arm versus a 48 mm needle (1 loop PDS) in the large bite arm contributed to the observed differences due to greater “buttonholing” of fascia with larger sized needles. The studies in this systematic review also used a range of needle sizes (from 2/0–2) so its specific impact remains uncertain. However, pre-clinical studies have shown that Duramesh™ has a reduced tendency to cut through tissue once implanted [10]. Applying only light suture tension to approximate tissues and avoid strangulation is a principle discussed in contemporary guidelines [7] and should be adhered to no matter the product used.

Prophylactic mesh augmentation during the index operation has garnered attention but despite the evidence has not been widely adopted due to impracticality. The PRIMA trial [6] was performed in patients with abdominal aortic aneurysm repair without violation of the gastrointestinal tract. Theoretical risk of contamination is often anecdotally cited as a reason for not performing prophylactic mesh augmentation and in two of the case series identified in this systematic review [14, 15], this concern was one of the indications for using mesh suture/strips instead. The ideal method of abdominal wall closure should prevent incisional hernia while minimising SSO risk and additional implantation time, particularly in comorbid patients where shorter operative times are beneficial. This is a potential strength of Duramesh™, but its incisional hernia and SSO rates need to be validated further with high-quality and unbiased prospective studies. The PRIMA trial [6] found only onlay prophylactic mesh to be statistically superior to primary suture. Onlay mesh placement, despite being relatively easy to implant, is considered an inferior biomechanical repair compared to retromuscular mesh placement for ventral and incisional hernias [8]. This perceived inferiority may have limited its widespread adoption for laparotomy closure. Duramesh™ may offer a pragmatic alternative particularly with patient populations where minimising operative complexity is crucial.

An important confounding factor in this review is length of follow-up. Nearly half of incisional hernias in a study by Fink et al. occurred more than a year after index operation, with rates rising from 12.6% at 1 year to 22.4% at 3 years post-surgery [31]. Burger et al. showed that recurrence following hernia repair continued even up to 10 years after surgery, particularly in suture repaired cases where the 10-year cumulative rate of recurrence was 63% for suture repair and 32% for prosthetic repair [32]. The follow-up duration of studies included in our systematic review ranged from 2.7–35.5 months, with four studies having 1 year follow-up or less [14, 15, 22, 24]. It is possible that shorter follow-up contributed to the relatively low incisional hernia occurrence. The series by Sarac [23] and Moradian [13], which had greater than 2 years mean follow-up, showed conflicting results with recurrence rates of 50% and 3% respectively. However, it should be noted that the patients studied were fundamentally different, comprising large midline ventral hernias in Sarac’s series [23] compared with small umbilical hernias in Moradian’s series [13]. It can therefore be argued that differences in operative complexity, BMI, CDC and VHWG grade meant that these patients were more likely to develop incisional hernia. Of note, the mesh strips in Sarac’s cohort were inserted using a Pulvertaft tendon weaver [23] rather than the “guiding suture”, as described originally by Dumanian [33]. Whether this has a significant impact compared to the differences in risk factors is unknown. Smoothness of mesh strip passage and tissue trauma is difficult to quantify and were not reported in any of the studies. We emphasise a need for continued long-term follow-up for patients treated with mesh suture/strips.

Variation in definitions and detection of incisional hernia may be another confounding factor in our review. A universally accepted definition for recurrence detection remains elusive, but recently a meeting of key opinion-leading hernia surgeons used a nominal group technique, which revealed that CT scanning should be the diagnostic method of choice [34]. Ethical issues around ionising radiation are greatly reduced by modern scanners but routine uptake in hernia trials remains a challenge [35]. An additional issue is whether small (<1 cm) fascial discontinuities visible on CT but without any definite intraabdominal protrusion should be classified as recurrence. Nonetheless, it is well-established that imaging increases the proportion of incisional hernia since impalpable recurrence is identified [36]. Although it may be argued that asymptomatic hernias are clinically irrelevant, Bloemen et al. propose that reporting imaging-detected hernias is justified since they are most at risk of incarceration, and some may enlarge over time or become symptomatic [37]. Notably, the STITCH trial, protocolled routine ultrasonography follow-up, with review of additional CT scanning if performed on clinical grounds [28]. In contrast, our review found imaging was not employed routinely and was only selectively used in three studies following equivocal physical examination. This may partly explain lower incisional hernia observed and emphasises the need for precise diagnosis for hernia trials.

The potential for larger volume knots when using mesh suture/strips compared to conventional sutures, raises concerns regarding patient comfort and SSO risk. The MOMENTUM trial [22], our only head-to-head comparative study between Duramesh™ and small-bite PDS closure, has so far demonstrated non-inferiority of Duramesh™ for SSO, pain score and patient satisfaction, potentially suggesting it is safe in the short-term (1 year follow-up). Marangi et al’s randomised controlled trial (RCT) of rectus diastasis repair [38], although excluded from our review, found Duramesh™ non-inferior to 0 Prolene for SSOs (including diastasis recurrence), pain score, and cosmetic satisfaction, using the validated BODY-Q score [39], but again follow-up duration was short at 6 months. Most patients in Moradian’s series of primary umbilical hernias were unable to feel the knot [13], although this aspect warrants further investigation in high-quality interventional trials. Other studies have shown that palpable sutures and stitch granulomas can occur with retained suture material and a thin subcutaneous fat layer around the umbilicus [40]. The median SSO result (17.4%) from our systematic review suggests mesh suture/strips may be similar to SSO rates reported in high-quality randomised controlled trials of prophylactic mesh repair of laparotomy, small-bite closure, and mesh repair of incisional hernia [6, 25, 27]. However, as can be seen in Figure 7, confidence intervals are wide with considerable heterogeneity between studies, preventing meta-analysis. As follows, there is currently insufficient high-quality and unbiased data to form a firm conclusion regarding its safety. Moreover, questions remain regarding the superiority of mesh suture over planar mesh for SSI rates. There are clear differences such as surface area of implant, pore size, tissue trauma, and devascularisation of tissue planes, which may theoretically lead to differences in SSI prevalence. Albeit substantially less invasive than planar mesh repair, the possibility of chronic mesh suture infection leading to explantation remains a critical area for future research.

An inherent limitation of our systematic review is that included trials were retrospective single-arm uncontrolled studies with critical risk of bias. Thus, patients were not randomised, and causality cannot be established. These were the best available data but multiple biases including selection bias and missing data bias are likely present. In the primary analysis, all data were pooled to compute a median value, and no distinction was made between patient variables such as hernia defect size, VHWG grade and ASA grade. Also, surgical variables such as surgeon experience, needle size and surgical technique may confound outcomes, and we suggest they should be standardised for future studies. Moreover, we were unable to adjust for patient risk factors, such as age, body mass index, or chronic obstructive pulmonary disease. Despite these limitations, the strength of this review is the use of a systematic approach and assessment of study quality using risk of bias tools that require rigorous methodology.

In summary, our systematic review found that mesh suture and mesh strips may be associated with low rates of short to medium-term incisional hernia occurrence, but this is merely anecdotal at this stage. Consequently, due to poor data quality, there is currently insufficient evidence to make any recommendations regarding Duramesh™ over current strategies for abdominal wall closure. Similarly, not enough high-quality data exists regarding product safety, so its safety profile remains uncertain. Well-designed RCTs with long-term follow-up are required to generate strong evidence. The abdominal wall community eagerly awaits the full results of the MOMENTUM study [22] and currently other RCTs are also recruiting [41, 42]. We suggest that future RCTs adhere to minimum standards [34] including at least 12 months of follow up, uniform technique for Duramesh™ implantation, and consistent use of imaging for hernia detection. High-quality comparative studies evaluating cost-effectiveness, quality of life, and other patient reported outcome measures are also required. Until then, Duramesh™ remains a potentially useful tool, but should be considered as part of a broader strategy of hernia prevention tailored to individual patient risk profiles and surgical contexts.