Characterization of ventral incisional hernia and repair using shear wave elastography

Port-site hernia recurrence at previous 5-mm laparoscopic access: case report and review of literature

Port-site hernia (PSH) of less than 10 mm is an exceptionally rare complication of minimally invasive surgery (MIS). To date, there have been no cases in the literature reporting recurrence of PSH from a 5 mm incision. We present the first case of PSH recurrence in a woman who underwent surgery for benign gynaecological pathology via a MIS approach. Her post-operative course was complicated by an episode of symptomatic hernia arising from a 5 mm accessory trocar which was surgically managed. A few months later she re-presented with the same symptoms and had a PSH recurrence of the same port-site. Two corrective surgeries employing different techniques were performed. The first episode was managed laparoscopically using interrupted stitches. On the other hand, the PSH recurrence was managed by placement of a mesh. Ultrasound played a crucial role in diagnostics, especially in the recurrent setting. Due to the complete absence of similar cases in the literature, the decision making around the management of a PSH recurrence from a 5 mm trocar site proved to be challenging. As MIS is the current standard of care, more cases are likely to occur, however despite the increasing number of surgical procedures performed via MIS, no established guidelines for managing such complications have been proposed. Trying to bridge this gap, we present the case report of the first case of PSH recurrence from a 5 mm accessory port and a review of the most significant literature available to date. We finally summarise the reported cases of PSH and the types of surgical repair conducted to highlight the absence of a standard of care.

Comparison of the Effectiveness of Ultrasound Imaging and Perioperative Measurement in the Diagnosis and Characterization of Incisional Hernia

Background

Incisional hernia (IH) is a common complication after abdominal surgery, and there is no gold standard imaging modality for its diagnosis. Although computed tomography is frequently used in clinical practice, it has limitations such as radiation exposure and relatively high cost. The aim of this study is to establish standardization and hernia typing by comparing preoperative ultrasound (US) measurements and perioperative measurements in IH cases.

Methods

The patients who were operated for IH in our institution between January 2020 and March 2021 were reviewed, retrospectively. In result, 120 patients were included in the study, and the cases had preoperative US images and perioperative hernia measurements. IH was divided into three subtypes as omentum (Type I), intestinal (Type II), and mixed (Type III) according to the defect content.

Results

Type I IH was detected in 91 cases, Type II IH in 14 cases, and Type III IH in 15 cases. When the diameters of IH types were compared for preoperative US and perioperative measurements, respectively, there was no statistical significance (P = 0.185 and P = 0.262). According to Spearman correlation, there was a positive very strong correlation between preoperative US measurements and perioperative measurements (ρ = 0.861 and P < 0.001).

Conclusion

As stated by our results, US imaging can be performed easily and quickly, providing a reliable way to accurately detect and characterize an IH. It can also facilitate the planning of surgical intervention in IH by providing anatomical information.

Amniotic fluid allograft enhances the host response to ventral hernia repair using acellular dermal matrix

Ventral hernia repair (VHR) with acellular dermal matrix (ADM) has high rates of recurrence that may be improved with allogeneic growth factor augmentation such as amniotic fluid allograft (AFA). We hypothesized that AFA would modulate the host response to improve ADM incorporation in VHR. Lewis rats underwent chronic VHR with porcine ADM alone or with AFA augmentation. Tissue harvested at 3, 14, or 28 days was assessed for region-specific cellularity, and a validated histomorphometric score was generated for tissue incorporation. Expression of pro-inflammatory (Nos1, Tnfα), anti-inflammatory (Arg1, Il-10, Mrc1) and tissue regeneration (Col1a1, Col3a1, Vegf, and alpha actinin-2) genes were quantified using quantitative reverse-transcription polymerase chain reaction. Amniotic fluid allograft treatment caused enhanced vascularization and cellularization translating to increased histomorphometric scores at 14 days, likely mediated by upregulation of pro-regeneration genes throughout the study period and molecular evidence of anti-inflammatory, M2-polarized macrophage phenotype. Collectively, this suggests AFA may have a therapeutic role as a VHR adjunct.

Polyester Mesh Functionalization with Nitric Oxide-Releasing Silica Nanoparticles Reduces Early Methicillin-Resistant Staphylococcus aureus Contamination

Background: Infected hernia mesh is a cause of post-operative morbidity. Nitric oxide (NO) plays a key role in the endogenous immune response to infection. We sought to study the efficacy of a NO-releasing mesh against methicillin-resistant Staphylococcus aureus (MRSA). We hypothesized that a NO-releasing polyester mesh would decrease MRSA colonization and proliferation. Materials and Methods: A composite polyester mesh functionalized with N-diazeniumdiolate silica nanoparticles was synthesized and characterized. N-diazeniumdiolate silica parietex composite (NOSi) was inoculated with 10⁴,10⁶, or 10⁸ colony forming units (CFUs) of MRSA and a dose response was quantified in a soy tryptic broth assay. Utilizing a rat model of contaminated hernia repair, implanted mesh was inoculated with MRSA, recovered, and CFUs were quantified. Clinical metrics of erythema, mesh contracture, and adhesion severity were then characterized. Results: Methicillin-resistant Staphylococcus aureus CFUs demonstrated a dose-dependent response to NOSi in vitro. In vivo, quantified CFUs showed a dose-dependent response to NOSi-PCO. Treated rats had fewer severe adhesions, less erythema, and reduced mesh contracture. Conclusions: We demonstrate the efficacy of a NO-releasing mesh to treat MRSA in vitro and in vivo. Creation of a novel class of antimicrobial prosthetics offers new strategies for reconstructing contaminated abdominal wall defects and other procedures that benefit from deploying synthetic prostheses in contaminated environments.

A Model-Based Approach to Investigate the Effect of a Long Bone Fracture on Ultrasound Strain Elastography

The mechanical behavior of long bones and fractures has been under investigation for many decades due to its complexity and clinical relevance. In this paper, we report a new subject-specific methodology to predict and analyze the mechanical behavior of the soft tissue at a bone interface with the intent of identifying the presence and location of bone abnormalities with high accuracy, spatial resolution, and contrast. The proposed methodology was tested on both intact and fractured rabbit femur samples with finite element-based 3-D simulations, created from actual femur computed tomography data, and ultrasound elastography experiments. The results included in this study demonstrate that elastographic strains at the bone/soft tissue interface can be used to differentiate fractured femurs from the intact ones on a distribution level. These results also demonstrate that coronal plane axial shear strain creates a unique contrast mechanism that can be used to reliably detect fractures (both complete and incomplete) in long bones. Kruskal-Wallis test further demonstrates that the contrast measure for the fracture group (simulation: 2.1286±0.2206; experiment: 2.7034 ± 1.0672) is significantly different from that for the intact group (simulation: 0 ± 0; experiment: 1.1540±0.6909) when using coronal plane axial shear strain elastography ( < 0.01). We conclude that: 1) elastography techniques can be used to accurately identify the presence and location of fractures in a long bone and 2) the proposed model-based approach can be used to predict and analyze strains at a bone fracture site and to better interpret experimental elastographic data.