Sublay repair results in superior mesh incorporation and histological fibrogenesis in comparison to onlay and primary suture in an experimental rat model

Electrospun meshes for abdominal wall hernia repair: Potential and challenges

Surgical meshes are widely used in abdominal wall hernia repairs. However, consensus on mesh treatment remains elusive due to varying repair outcomes, especially with the introduction of new meshes, posing a substantial challenge for surgeons. Addressing these issues requires communicating the features of emerging candidates with a focus on clinical considerations. Electrospinning is a versatile technique for producing meshes with biomechanical architectures that closely mimic the extracellular matrix and enable incorporation of bioactive and therapeutic agents into the interconnective porous network, providing a favorable milieu for tissue integration and remodeling. Although this promising technique has drawn considerable interest in mesh fabrication and functionalization, currently developed electrospun meshes have limitations in meeting clinical requirements for hernia repair. This review summarizes the advantages and limitations of meshes prepared through electrospinning based on biomechanical, biocompatible, and bioactive properties/functions, offering interdisciplinary insights into challenges and future directions toward clinical mesh-aided hernia repair. STATEMENT OF SIGNIFICANCE: Consensus for hernia treatments using surgical meshes remains elusive based on varying repair outcomes, presenting significant challenges for researchers and surgeons. Differences in understanding mesh between specialists, particularly regarding material characteristics and clinical requirements, contribute to this issue. Electrospinning has been increasingly applied in mesh preparation through various approaches and strategies, aiming to improve abdominal wall hernia by restoring mechanical, morphological and functional integrity. However, there is no comprehensive overview of these emerging meshes regarding their features, functions, and clinical potentials, emphasizing the necessity of interdisciplinary discussions on this topic that build upon recent developments in electrospun mesh and provide insights from clinically practical prospectives.

Defect width as a percentage of transverse abdominal diameter: An index to predict the requirement for component separation in incisional hernia repair

Purpose

Preoperative decision making prior to incisional hernia repair brings benefits but also presents challenges. Defect width (DW) is the key index in hernia staging but does not precisely indicate the requirement for component separation (CS). DW as a percentage of transverse abdominal diameter (TAD) determined by CT imaging was investigated for its capacity to indicate the necessity of CS for successful defect closure under physiological tension.

Methods

A total of 116 patients treated for incisional hernia by surgery between April 1st, 2015 and September 30th, 2020 were enrolled and clinical data retrospectively analyzed. All hernias were repaired with defect closure and mesh reinforcement. 82 patients received Rives-Stoppa repair (RS group) and 34 Rives-Stoppa repair with CS (CS group). Preoperative CT images were reviewed to measure maximum DW and TAD at umbilical level and the DW/TAD percentage (DTP) calculated. Accuracies of DW and DTP in predicting necessity of CS were compared through statistical analysis.

Results

Mean RS DW was 59.41 ± 18.70 mm and CS DW 105.76 ± 13.47 mm (p = 0.000). Mean RS DW/TAD percentage was 21.25 ± 6.48 and CS DW/TAD 38.56 ± 6.26 (p < 0.05). Area under the curve (AUC) for receiver operating characteristic (ROC) curves gave values of 0.798 for DW and 0.825 for DTP (p < 0.05).

Conclusion

DTP is a reliable index with greater accuracy than DW for prediction of the necessity of CS in incisional hernia repair.

Different cellular and immunohistochemical abdominal wall cicatrization parameters evaluation in comparison with sublay, onlay, and ipom technique in an experimental rat model

PURPOSE

Incisional hernia (IH) occurs when there is a partial or complete solution of continuity of a fascia previously incised. Systematic reviews demonstrate that surgical treatment of IHs with the use of meshes are approximately 16%. Meta-analyses have demonstrated the superiority of mesh placement using sublay technique, but without a pathophysiological explanation. Thus, we aim to evaluate the different techniques of mesh positioning in an experimental model.

METHODS

Fifty rats were distributed into five groups; control; simulation (SM)-submitted to laparotomy only; onlay-the mesh was positioned in onlay fashion; retromuscular (SL)-the mesh was positioned in a sublay fashion; intraperitoneal (IPOM)-positioning of the mesh adjacent to the transversalis fascia, inside the cavity. After 60 days, adhesions, tensiometry, histology, and immunohistochemistry were addressed.

RESULTS

The IPOM group had the most adhesions, together with the SL group, with significantly relevant results. The SL group had higher values of tensiometric evaluation, while the IPOM group had the lowest mean in the tensiometry evaluation, being even lower than the SM group. Regarding histological and immunohistochemical findings, the SL group had a higher pixel number count compared to the groups, with statistical significance, in addition to higher expression of polymorphonuclear infiltrate and CD68 markers.

CONCLUSION

The mesh positioning in sublay compartment is associated with the development of more pronounce minimum tensile force required for detaching the surrounding abdominal wall tissues it was incorporated. The intensity of these findings correlates to the different histological and immunohistochemical profiles observed following each repair, since SL group was characterized by a higher proportion of collagen, inflammatory, and reparative elements. Characterizing these pro-healing elements and its counterparts will allow the development of new therapeutic tools which could be added to the still far-from-ideal current therapeutic options for IH treatment.

Midterm Results of the Open and Minimally Invasive Transversus Abdominis Release Technique for the Treatment of Abdominal Wall Hernias in an Academic Center

Introduction: Large hernia defects are a challenge for general and specialized hernia surgeons. The transversus abdominis release (TAR) technique has revolutionized the treatment of complex hernias since it allows the closure of large midline hernias, as well as hernias in different locations. This study aims to report the experience with the TAR technique and mid-term results in the first 101 patients. Methods: Non-concurrent cohort review of our prospectively collected electronic database. All patients submitted to a TAR (open or minimally invasive eTEP-TAR) from 2017 to 2020 were included. Demographic data, comorbidities, hernia characteristics, preoperative optimization, intraoperative variables, and clinical outcomes were gathered. The main outcomes of this study are hernia recurrences and surgical morbidity. Results: A total of 101 patients were identified. The median follow-up was 26 months. Mean age and body mass index was 63 years and 31.4 Kg/m2, respectively. Diabetes was present in 22% of patients and 43% had at least one previous hernia repair. Nineteen patients had significant loss of domain. Mean hernia size and area were 13 cm and 247 cm2, respectively. Ninety-six percent of cases were clean or clean-contaminated. The mean operative time was 164 min and all patients received a synthetic mesh. We diagnosed two hernia recurrences and the overall (medical and surgical) complication rate was 32%. The hernia-specific complication rate was 17%, with seven surgical site infections and seven surgical site occurrences requiring procedural interventions. Notably, weight loss was associated with a lower risk of SSOPI and reoperations. Conclusion: We show an encouraging 2% of recurrences in the mid-term follow-up in the setting of clinically complex hernia repair. However, we observed a high frequency of overall and hernia-specific complications pointing to the complexity of the type of surgery itself and the patients we operated on.

The experimental methodology and comparators used for in vivo hernia mesh testing: a 10-year scoping review

PURPOSE

Before being marketed, hernia mesh must undergo in vivo testing, which often includes biomechanical and histological assessment. Currently, there are no universal standards for this testing and methods vary greatly within the literature. A scoping review of relevant studies was undertaken to analyse the methodologies used for in vivo mesh testing.

METHODS

Medline and Embase databases were searched for relevant studies. 513 articles were identified and 231 duplicates excluded. 126 papers were included after abstract and full text review. The data extraction was undertaken using standardised forms.

RESULTS

Mesh is most commonly tested in rats (53%). 78% of studies involve the formation of a defect; in 52% of which the fascia is not opposed. The most common hernia models use mesh to bridge an acute defect (50%). Tensile strength testing is the commonest form of mechanical testing (63%). Testing strip widths and test speeds vary greatly (4-30 mm and 1.625-240 mm/min, respectively). There is little consensus on which units to use for tensile strength testing. Collagen is assessed for its abundance (54 studies) more than its alignment (18 studies). Alignment is not measured quantitatively. At least 21 histological scoring systems are used for in vivo mesh testing.

CONCLUSIONS

The current practice of in vivo mesh testing lacks standardisation. There is significant inconsistency in every category of testing, both in methodology and comparators. We would call upon hernia organisations and materials testing institutions to discuss the need for a standardised approach to this field.

Prevention of incisional hernia with a reinforced tension line (RTL) versus primary suture only in midline laparotomies: 3-year follow-up in a randomized clinical trial

PURPOSE

Incisional hernia (IH) has an incidence of 10-23%, which can increase to 38% in specific risk groups. The objective of this study is to report the results at 3 years of follow-up of the use of the reinforced tension line (RTL) technique compared with primary suture only (PSO) closure in the prevention of IH in high-risk patients undergoing laparotomy.

METHODS

Open randomized controlled clinical trial. Included were patients older than 18 years who underwent midline laparotomy, emergency or scheduled, who were considered high risk, and who completed 3-year follow-up. The patients were randomized 1:1 to the RTL technique or to PSO. The objective was to report the incidence of IH and the complications associated with the closure method. Intention-to-treat analysis and Cox regression were performed.

RESULTS

A total of 124 patients were randomized; 51 patients from the RTL group and 53 patients from the PSO group finished the 3-year follow-up. The incidence of IH was higher in the PSO group (15/53, 28.3%) than the RTL group (5/51, 9.8%) (p = 0.016, OR 0.35, 95% CI 0.14-0.88, number needed to treat 5.4, log-rank test p = 0.017). The groups were similar in the rates of surgical site infection, hematoma, seroma, and postoperative pain during follow-up.

CONCLUSIONS

The RTL technique is useful in the prevention of IH when compared with PSO in high-risk midline laparotomy patients, and it is not associated with a higher percentage of complications.

TRIAL REGISTRATION

Local Committee CI-HRAEB-2013-020. March 13, 2013.

CLINICAL TRIALS

NCT02136628, retrospectively registered.