Consequences and complications of peritoneal adhesions

Recent Advances in Functional Hydrogel for Repair of Abdominal Wall Defects: A Review

The abdominal wall plays a crucial role in safeguarding the internal organs of the body, serving as an essential protective barrier. Defects in the abdominal wall are common due to surgery, infection, or trauma. Complex defects have limited self-healing capacity and require external intervention. Traditional treatments have drawbacks, and biomaterials have not fully achieved the desired outcomes. Hydrogel has emerged as a promising strategy that is extensively studied and applied in promoting tissue regeneration by filling or repairing damaged tissue due to its unique properties. This review summarizes the five prominent properties and advances in using hydrogels to enhance the healing and repair of abdominal wall defects: (a) good biocompatibility with host tissues that reduces adverse reactions and immune responses while supporting cell adhesion migration proliferation; (b) tunable mechanical properties matching those of the abdominal wall that adapt to normal movement deformations while reducing tissue stress, thereby influencing regulating cell behavior tissue regeneration; (c) drug carriers continuously delivering drugs and bioactive molecules to sites optimizing healing processes enhancing tissue regeneration; (d) promotion of cell interactions by simulating hydrated extracellular matrix environments, providing physical support, space, and cues for cell migration, adhesion, and proliferation; (e) easy manipulation and application in surgical procedures, allowing precise placement and close adhesion to the defective abdominal wall, providing mechanical support. Additionally, the advances of hydrogels for repairing defects in the abdominal wall are also mentioned. Finally, an overview is provided on the current obstacles and constraints faced by hydrogels, along with potential prospects in the repair of abdominal wall defects.

What Should I Use? Impact of Adhesion Barriers on Postoperative Abdominal Complications: A Systematic Review

BACKGROUND

Adhesions are a feared complication of abdominal surgery. There have been many new adhesion barriers developed and tested; however, there is no recent systematic review analyzing all the published literature. To address this, we aimed to analyze the different types of adhesion barriers, and determine their effects on postoperative outcomes in patients.

METHODS

A total of 14,038 articles utilizing adhesion barriers in abdominal surgery were retrieved from the PubMed, EMBASE, and Scopus databases. Inclusion criteria were: patients undergoing abdominal surgery, patients receiving an adhesion barrier, and reported postoperative outcomes. Two reviewers independently screened titles/abstracts and full-text articles using Covidence. The ROBINS-I tool was used to assess the quality of the included studies. Study protocol: Prospero CRD42023458230.

RESULTS

A total of 20 studies, with no overall high risk of bias, with 171,792 patients were included. Most studies showed an equivocal benefit for adhesion barriers, with no singular adhesion barrier type that had definitive superior outcomes compared to the others. Bioresorbable barriers emerged as the most extensively researched adhesion barrier type, exhibiting promising results in colorectal surgery. Starch-based adhesion barriers also exhibited a reduction in overall postoperative bowel obstructions and may be beneficial for stoma sites and port closures. On the other hand, many studies raised concerns regarding complications, including risk of abscess formation, fistula development, peritonitis, and anastomotic leakage.

CONCLUSIONS

Adhesion barriers should be considered on a case-by-case basis, however, they should not be utilized prophylactically in all abdominal surgeries due to their risk of complications.

Does the presence of abdominal wall adhesions make gynecologic robotic surgery difficult?

This study aimed to assess the status of abdominal wall adhesions resulting from prior surgeries and their impact on the outcomes of robotic surgery. We retrospectively reviewed clinical information, surgical outcomes, and the status of abdominal wall adhesions in patients who underwent gynecologic robotic surgery at Yamanashi Central Hospital, between April 2018 and March 2023. Abdominal wall adhesions were classified into seven locations and their presence was assessed at each site. Among the 768 cases examined, 196 showed the presence of abdominal wall adhesions. Notably, patients with a history of abdominal surgery exhibited a significantly higher incidence of abdominal wall adhesions than those without such surgical history, although no significant difference was observed in the frequency of adhesions in the upper left abdomen. Patients with a history of gynecologic, gastrointestinal, or biliopancreatic surgeries were more likely to have adhesions at the umbilicus or upper abdomen sites where trocars are typically inserted during robotic surgery. Although cases with abdominal wall adhesions experienced longer operative times than those without, there was no significant difference in estimated blood loss. In 13 cases (1.7%), adjustments in trocar placement were necessary due to abdominal wall adhesions, although none of the cases required conversion to open or conventional laparoscopic surgery. Abdominal wall adhesions pose challenges to minimally invasive procedures, emphasizing the importance of predicting these adhesions based on a patient's surgical history to safely perform robotic surgery. These results suggest that the robot's flexibility proves effective in managing abdominal wall adhesions.

Can we predict peritoneal adhesions formation after cesarean delivery?

OBJECTIVE

To examine demographic and obstetrical factors that are associated with adhesion formation following cesarean delivery.

METHODS

We conducted a population-based study that included all women over 18 years og age who underwent two cesarean deliveries between the years 1988 and 2016 in a large tertiary medical center. We excluded women with adhesions already diagnosed during the first cesarean delivery, history of other abdominal or pelvic surgery, history of pelvic infection or pelvic inflammatory disease, history of endometriosis and history of uterine Müllerian anomalies. In addition, women with a classical or T-shaped uterine incision, non-singleton pregnancies, and fetal chromosomal or structural abnormalities were excluded.

RESULTS

During the study period, 32.6% (n = 2283) of women were diagnosed with peritoneal adhesions during the second cesarean delivery. Factors found to be significantly associated with peritoneal adhesions were maternal age 35 years or older at the first cesarean delivery, Bedouin Arab ethnicity, composite of intrapartum and postpartum infectious morbidity, and cesarean deliveries that were performed after the onset of labor. In contrast, having a previous vaginal birth was found to be protective.

CONCLUSIONS

Our results suggest that a woman's characteristics at her first cesarean delivery and her obstetrical history may be predictive of the likelihood of adhesion formation.

Transvaginal extraperitoneal single-port laparoscopic sacrocolpopexy for apical prolapse after total/subtotal hysterectomy: Chinese surgeons' initial experience

BACKGROUND

To introduce a novel technique of transvaginal extraperitoneal single-port laparoscopic sacrocolpopexy (ESLS) for apical prolapse and to evaluate the feasibility and short-term outcomes of this technique.

METHODS

Sixteen patients were enrolled to undergo ESLS between January 2020 and May 2021. Perioperative outcomes were included. Short-term results were assessed by Pelvic Floor Distress Inventory-20 (PFDI-20), Pelvic Organ Prolapse Quantification (POP-Q) scores, mesh exposure and prolapse recurrence.

RESULTS

A total of 14/16 cases (87.5%) were successfully completed. The mean operation time was 118 min (range 85-160), and the mean blood loss was 68 ml (range 20-100). The mean postoperative visual analog scale (VAS) pain score at 24 h was 0.7. No intraoperative complications occurred except for one patient who developed subcutaneous emphysema. All patients gained a significant improvement in both physical prolapse and quality of life at 12 months after surgery, and there was no mesh exposure or prolapse recurrence.

CONCLUSIONS

Our experience showed that transvaginal ESLS is a feasible and effective technique for apical prolapse with a previous hysterectomy. However, this technique should be performed by surgeons with extensive experience both in vaginal surgery and laparoscopic single-port surgery.

Real-time fluorescence-guided adhesiolysis with indocyanine green in intra-abdominal surgery (with video)

Intra-abdominal adhesions have consistently posed a challenge for surgeons during procedures. This study aims to investigate the feasibility of utilizing indocyanine green (ICG) in conjunction with near-infrared imaging for the detection of intra-abdominal adhesions. In vitro, we analyzed factors affecting ICG fluorescence. We divided SD rats into groups to study ICG excretion in different digestive tract regions. Additionally, we reviewed surgical videos from previous cholecystectomy cases, categorizing them by ICG injection timing and assessing fluorescence imaging in various digestive tract regions. Finally, we preoperatively injected ICG into two cholecystectomized patients with abdominal adhesions, guiding intraoperative adhesiolysis with near-infrared fluorescence imaging. In vitro, we observed a significant influence of protein and ICG concentrations on ICG fluorescence intensity. Our rat experiments unveiled a strong and highly significant correlation (Kendall's tau-b = 1, P < 0.001) between the timing of ICG injection and the farthest point of intestinal fluorescence. A retrospective case analysis further validated this finding (Kendall's tau-b = 0.967, P < 0.001). Under the guidance of fluorescence navigation, two cholecystectomized patients with intra-abdominal adhesions successfully underwent adhesiolysis, and no postoperative complications occurred. The intraoperative combination of ICG with near-infrared fluorescence imaging effectively enhances the visibility of the liver, bile ducts, and various segments of the gastrointestinal tract while providing real-time navigation. This real-time fluorescence guidance has the potential to aid surgeons in the dissection of intra-abdominal adhesions.

Improving the Physical Properties of Starch-Based Powders for Potential Anti-Adhesion Applications

Postoperative adhesion is one of the most common complications that occur during and after surgery; thus, materials that can prevent adhesion are often applied. Starch powders with a high water absorption capacity are preferred, and many studies have focused on increasing the water absorption of modified starches, as native starch powders display poor water-holding capacities. The effects of salts on the physical properties of acetylated distarch phosphate potato starch powders were investigated here. Changes in functional groups, the crystal structures of modified starch, particle morphologies, water absorption, viscosity, and in vivo adhesion were investigated. The results showed that salts greatly improved the water absorption and viscosity of acetylated distarch phosphate potato starch powders. Among the three different salt-modified starch powders, NaCl-modified starch powders displayed higher water absorption and viscosity and demonstrated better in vivo anti-adhesion performance. The results of this study propose a potential biomaterial that may function as an anti-adhesive, potentially leading to reduced surgical risks and a better quality of life for patients.

Evaluation of the effect of previous endometriosis surgery on clinical and surgical outcomes of subsequent endometriosis surgery

PURPOSE

Patients often undergo repeat surgery for endometriosis, due to recurrent or residual disease. Previous surgery is often considered a risk factor for worse surgical outcome. However, data are scarce concerning the influence of subsequent endometriosis surgery.

METHODS

A retrospective study in a centre of expertise for endometriosis was conducted. All endometriosis subtypes and intra-operative steps were included. Detailed information regarding surgical history of patients was collected. Surgical time, intra-operative steps and major post-operative complications were obtained as outcome measures.

RESULTS

595 patients were included, of which 45.9% had previous endometriosis surgery. 7.9% had major post-operative complications and 4.4% intra-operative complications. The patient journey showed a median of 3 years between previous endometriosis surgeries. Each previous therapeutic laparotomic surgery resulted on average in 13 additional minutes (p = 0.013) of surgical time. Additionally, it resulted in more frequent performance of adhesiolysis (OR 2.96, p < 0.001) and in a higher risk for intra-operative complications (OR 1.81, p = 0.045), however no higher risk for major post-operative complications (OR 1.29, p = 0.418). Previous therapeutic laparoscopic endometriosis surgery, laparotomic and laparoscopic non-endometriosis surgery showed no association with surgical outcomes. Regardless of previous surgery, disc and segmental bowel resection showed a higher risk for major post-operative complications (OR 3.64, p = 0.017 respectively OR 3.50, p < 0.001).

CONCLUSION

Previous therapeutic laparotomic endometriosis surgery shows an association with longer surgical time, the need to perform adhesiolysis, and more intra-operative complications in the subsequent surgery for endometriosis. However, in a centre of expertise with experienced surgeons, no increased risk of major post-operative complications was observed.

Multifunctional Oxidized Dextran-Metformin as a Tissue-Adhesive Hydrogel to Prevent Postoperative Peritoneal Adhesions in Patients with Metabolic Syndrome

Patients with metabolic syndrome (MetS) undergoing surgery are at high risk of developing peritoneal adhesions and other severe postoperative complications. However, the single shielding function and absence of physiological activity render conventional methods less useful in preventing adhesions in patients with MetS. To address this challenge, a convenient method is introduced for developing a novel tissue-adhesive hydrogel called oxidized dextran-metformin (ODE-ME) via Schiff base linkages. This injectable ODE-ME hydrogel exhibits excellent tissue-adhesive properties and various physiological functions, particularly enhanced antibacterial effects. Furthermore, in vivo experiments demonstrate that the hydrogel can effectively alleviate hyperglycemia, reduce excessive inflammation, and improve fibrinolytic activity in MetS mice, thereby preventing adhesions and promoting incisional healing. The hydrogel concurrently isolates injured tissues and lowers the blood glucose levels immediately after surgery in mice. Therefore, the ODE-ME hydrogel functions as a multifunctional barrier material and has potential for preventing postoperative peritoneal adhesions in patients with MetS in clinical settings.

Risk factors for adverse outcomes following paraesophageal hernia repair among obese patients

BACKGROUND

Although obesity is an established risk factor for adverse outcomes after paraesophageal hernia repair (PEHR), many obese patients nonetheless receive PEHR. The purpose of this study was to explore risk factors for adverse outcomes of PEHR among this high-risk cohort. We hypothesized that obese patients may have other risk factors for adverse outcomes following PEHR.

METHODS

A retrospective study of adult obese patients who underwent minimally invasive PEHR from 2017 to 2019 was performed. Patients were excluded for BMI < 30 or if they had concomitant bariatric surgery at time of PEHR. The primary outcome of interest was a composite adverse outcome (CAO) defined as having any of the four following outcomes after PEHR: persistent GERD > 30 d, persistent dysphagia > 30 d, recurrence, or reoperation. Chi-square and t-test analysis was used to compare demographic and clinical characteristics. Multivariable logistic regression analysis was used to evaluate independent predictors of CAO.

RESULTS

In total, 139 patients met inclusion criteria with a median follow-up of 19.7 months (IQR 8.8-81). Among them, 51/139 (36.7%) patients had a CAO: 31/139 (22.4%) had persistent GERD, 20/139 (14.4%) had persistent dysphagia, 24/139 (17.3%) had recurrence, and 6/139 (4.3%) required reoperation. On unadjusted analysis, patients with a CAO were more likely to have a history of prior abdominal surgery (86.3% vs 70.5%, p = 0.04) and were less likely to have undergone a preoperative CT scan (27.5% vs 45.5%, p = 0.04). On multivariable analysis, previous abdominal surgery was independently associated with an increased likelihood of CAO whereas age and preoperative CT scan had a decreased likelihood of CAO.

CONCLUSIONS

Although there were adverse outcomes among obese patients, minimally invasive PEHR may be feasible in a subset of patients at specialized centers. These findings may help guide the appropriate selection of obese patients for PEHR.

Antiadhesive Nanofibrous Materials for Medicine: Preventing Undesirable Tissue Adhesions

Undesirable postoperative tissue adhesions remain among the most common complications after surgery. Apart from pharmacological antiadhesive agents, various physical barriers have been developed in order to prevent postoperative tissue adhesions. Nevertheless, many introduced materials suffer from shortcomings during in vivo application. Thus, there is an increasing need to develop a novel barrier material. However, various challenging criteria have to be met, so this issue pushes the research in materials to its current limits. Nanofibers play a major role in breaking the wall of this issue. Due to their properties, such as a large surface area for functionalization, tunable degradation rate, or the possibility of layering individual nanofibrous materials, it is feasible to create an antiadhesive surface while maintaining biocompatibility. There are many ways to produce nanofibrous material; electrospinning is the most used and versatile technique. This review reveals the different approaches and puts them into context.

Adhesive Small Bowel Obstruction: A Review

Adhesion is a leading cause of small bowel obstruction. Adhesive small bowel obstruction has significant challenges in diagnosis, treatment and prevention with considerable impact on morbidity and socioeconomic burden. Small bowel obstruction caused by adhesion or any other aetiology is clinically indistinguishable due to similar clinical presentation. Computed Tomography scans and water-soluble contrast studies are more specific in diagnosis and possess value in predicting the need for surgery. Surgical management is indicated only in complicated cases or failed conservative treatments with the majority resolving with non-operative management. However, there is no clear-cut consensus about the timing of operative intervention. Meticulous surgical practice is the keystone in preventing adhesion formation despite the availability of numerous pharmacological and surgical strategies. This review aims to update the current knowledge of the pathophysiology of adhesion formation, treatment options and various prevention modalities of adhesive small bowel obstruction.

KEYWORDS

diagnosis; laparotomy; prevention; surgery.

Novel, Blended Polymeric Microspheres for the Controlled Release of Methotrexate: Characterization and In Vivo Antifibrotic Studies

Low dose methotrexate (MTX) is known to effectively decrease type I collagen production in dermal fibroblasts, while increasing the matrix metalloproteinase-1 (MMP-1) production in vitro. For in vivo use as an antifibrotic agent on wounds, a linear and extended controlled release formulation of MTX is required. The objective of this study was to optimize the fabrication of MTX-loaded polymeric microspheres with such properties, and to test the efficacy for the prevention of fibrosis in vivo. Poly lactic-co-glycolic acid (PLGA), Poly (L-lactic acid) (PLLA) and the diblock copolymer, methoxypolyethylene glycol-block-poly (D, L-lactide) (MePEG-b-PDLLA), were used to fabricate microspheres, which were then characterized in terms of size, drug encapsulation efficiency, and in vitro release profiles. The optimized formulation (PLGA with diblock copolymer) showed high drug encapsulation efficiency (>80%), low burst release (~10%) and a gradual release of MTX. The amphipathic diblock copolymer is known to render the microsphere surface more biocompatible. In vivo, these microspheres were effective in reducing fibrotic tissue which was confirmed by quantitative measurement of type I collagen and α-smooth muscle actin expression, demonstrating that MTX can be efficiently encapsulated in PLGA microspheres to provide a delayed, gradual release in wound beds to reduce fibrosis in vivo.

The preventive effect of omega-3 fish oil on the formation of peritoneal adhesions

<br><b>Introduction:</b> Postoperative peritoneal adhesions that form after abdominal surgery still continue to exist as an unresolved health problem.</br> <br><b>Aim:</b> The aim of the study is to examine whether omega-3 fish oil has a preventive effect on postoperative peritoneal adhesions.</br> <br><b>Material and methods:</b> Twenty-one female Wistar albino rats were separated into 3 groups (sham, control and experimental), each consisting of 7 rats. In the sham group, only laparotomy was performed. In both the control and experimental group rats, the right parietal peritoneum and cecum were traumatised to form petechiae. Following this procedure, the abdomen was irrigated with omega-3 fish oil in the experimental group. The rats were re-explored on the 14^th postoperative day and any adhesions were scored. Tissue samples and blood samples were taken for histopathological and biochemical analysis.</br> <br><b>Results:</b> None of the rats that were administered omega-3 fish oil developed macroscopic postoperative peritoneal adhesions (P = 0.005). The omega-3 fish oil formed an anti-adhesive lipid barrier on the injured tissue surfaces. Microscopic evaluation revealed diffuse inflammation with excessive connective tissue and fibroblastic activity in the control group rats, while foreign body reactions were common in the omega-3 rats. The mean amount of hydroxyproline in samples from injured tissues was significantly lower in the omega-3 rats than in the control rats (P = 0.004).</br> <br><b>Conclusion:</b> Intraperitoneal application of omega-3 fish oil prevents postoperative peritoneal adhesions by forming an anti-adhesive lipid barrier on injured tissue surfaces. However, further studies are needed to determine whether this adipose layer is permanent or will be resorbed over time.</br>.

HPLC/MS characterization of Syzygium aromaticum L. and evaluation of its effects on peritoneal adhesion: Investigating the role of inflammatory cytokines, oxidative factors, and fibrosis and angiogenesis biomarkers

The dried flower bud of Syzygium aromaticum L. (S. aromaticum) (Myrtaceae), cloves, have been used for their analgesic and anti-inflammatory activities. Peritoneal adhesion (PA) is the most common complication of abdominal and pelvic surgeries, which causes significant adverse effects and severe economic burden. The present study aimed to evaluate the preventive effect of S. extract (SAE) on PA formation in a rat model. Male Wistar 8-week-old rats were randomly divided into sham, control (received vehicle), and treatment (0.25%, 0.5%, and 1% w/v of SAE) groups. The adhesion and related factors were examined using the Nair scoring system and immunological and biochemical kits for the levels of inflammatory cytokines [interleukin (IL)-6 and tumor necrosis factor (TNF)-α], growth factors [transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF)], oxidative [nitric oxide (NO) and malondialdehyde (MDA)], and anti-oxidative [glutathione (GSH)] factors. Our results figured out that the adhesion score and IL-6, TNF-α, TGF-β1, VEGF, NO, and MDA levels were significantly increased, but the GSH level was decreased in the control group compared to the sham group (p < 0.001-0.05). On the other hand, the 0.25% SAE group had a lower adhesion score, and IL-6, TNF-α, TGF-β1, VEGF, NO, and MDA levels were significantly decreased compared with the vehicle group, and the level of GSH was increased (p < 0.001-0.05). SAE could efficiently reduce adhesion score and regulate inflammatory cytokines, oxidative and anti-oxidative factors, and biomarkers of fibrosis and angiogenesis. Therefore, clove extract can be considered a potential candidate for PA management.

Efficacy of gelatin sponge in the prevention of post-surgical intra-abdominal adhesion in a rat model

Although different products have been developed to prevent post-surgical adhesion, their efficacy remains unsatisfactory. This study aimed to evaluate the efficacy of the gelatin sponge in the prevention of post-surgical intra-abdominal adhesions in a rat model. Rats were randomly divided into sham, adhesion, and gelatin groups. All rats, except the sham group, underwent cecal abrasion to establish an adhesion model. After celiotomy, a sterile gelatin sponge was applied intra-abdominal on the abraded cecum in the gelatin group. Rats were sacrificed on day 14 post-surgery and intra-abdominal adhesions were evaluated and scored. Adhesion tissues were evaluated by histological, histochemical, and immunohistochemical analysis. Intra-abdominal adhesions were recorded in all rats of the adhesion group. Intra-abdominal application of gelatin sponge significantly (P < 0.001) reduced intra-abdominal adhesions by 91% in the gelatin group relative to the adhesion group. The histological analysis revealed a marked decrease (P < 0.001) in the inflammatory score and neovascularization in the gelatin group. The histochemical analysis found that gelatin sponge administration reduced adhesion formation and thickness of adhesion tissue. Moreover, gelatin sponge significantly (P < 0.0001) increased MMP-9 expression and decreased macrophage marker expression in adhesive tissue. This study revealed that the application of gelatin sponge markedly reduced the post-surgical intra-abdominal adhesions and suggests new guidance for using gelatin sponge as an anti-adhesive substance in clinical practice.

Localized bioelectrical conduction block from radiofrequency gastric ablation persists after healing: safety and feasibility in a recovery model

Gastric ablation has demonstrated potential to induce conduction blocks and correct abnormal electrical activity (i.e., ectopic slow-wave propagation) in acute, intraoperative in vivo studies. This study aimed to evaluate the safety and feasibility of gastric ablation to modulate slow-wave conduction after 2 wk of healing. Chronic in vivo experiments were performed in weaner pigs (n = 6). Animals were randomly divided into two groups: sham-ablation (n = 3, control group; no power delivery, room temperature, 5 s/point) and radiofrequency (RF) ablation (n = 3; temperature-control mode, 65°C, 5 s/point). In the initial surgery, high-resolution serosal electrical mapping (16 × 16 electrodes; 6 × 6 cm) was performed to define the baseline slow-wave activation profile. Ablation (sham/RF) was then performed in the mid-corpus, in a line around the circumferential axis of the stomach, followed by acute postablation mapping. All animals recovered from the procedure, with no sign of perforation or other complications. Two weeks later, intraoperative high-resolution mapping was repeated. High-resolution mapping showed that ablation successfully induced sustained conduction blocks in all cases in the RF-ablation group at both the acute and 2 wk time points, whereas all sham-controls had no conduction block. Histological and immunohistochemical evaluation showed that after 2 wk of healing, the lesions were in the inflammation and early proliferation phase, and interstitial cells of Cajal (ICC) were depleted and/or deformed within the ablation lesions. This safety and feasibility study demonstrates that gastric ablation can safely and effectively induce a sustained localized conduction block in the stomach without disrupting the surrounding slow-wave conduction capability.NEW & NOTEWORTHY Ablation has recently emerged as a tool for modulating gastric electrical activation and may hold interventional potential for disorders of gastric function. However, previous studies have been limited to the acute intraoperative setting. This study now presents the safety of gastric ablation after postsurgical recovery and healing. Localized electrical conduction blocks created by ablation remained after 2 wk of healing, and no perforation or other complications were observed over the postsurgical period.

Self-healing, injectable hydrogel based on dual dynamic covalent cross-linking against postoperative abdominal cavity adhesion

Clinically, increasing the peritoneal barrier is an effective adjunct to reducing postoperative peritoneal adhesion. This study presents a facile template for preparing a supramolecular hybrid hydrogel through dynamic covalent cross-linking between carboxymethyl chitosan (CMCS), 2-formylphenylboronic acid (2-FPBA), and quercetin (Que). The as-prepared complex CMCS/2-FPBA/Que (CFQ) hydrogel exhibited favorable antibacterial, anti-inflammatory, and antioxidant effects. A L929 cytotoxicity evaluation confirmed the favorable cytocompatibility of the CFQ hydrogel. The postoperative anti-adhesion ability of the CFQ hydrogel was further evaluated in rats with lateral wall defects and cecal abrasions. Compared with control groups, the tissue adhesion rate was significantly reduced by increasing the Que concentration in all the hydrogel-treated groups. Additionally, the sustained-release time of the C3F0.8Q0.08 hydrogel can exceed 14 days, which is highly desirable for clinical wound treatment. STATEMENT OF SIGNIFICANCE: Postoperative adhesions are a very common postoperative complication that seriously affects the quality of life of patients. The currently commonly used methods for preventing adhesion mainly use degradable barrier materials for physical separation. In this study, we prepared a dual dynamic covalently cross-linked CFQ hydrogel, which is not only degradable and injectable, but also has multiple properties such as antibacterial, antioxidant and anti-inflammatory, which can effectively prevent postoperative adhesion and promote wound healing.

Variability in the management of adhesive small bowel obstruction in children

BACKGROUND

This study assessed inter-hospital variability in operative-vs-nonoperative management of pediatric adhesive small bowel obstruction (ASBO).

METHODS

A multi-institutional retrospective study was performed examining patients 1-21 years-of-age presenting with ASBO from 2010 to 2019 utilizing the Pediatric Health Information System. Multivariable mixed-effects logistic regression was performed assessing inter-hospital variability in operative-vs-nonoperative management of ASBO.

RESULTS

Among 6410 pediatric ASBO admissions identified at 46 hospitals, 3,239 (50.5%) underwent surgery during that admission. The hospital-specific rate of surgery ranged from 35.3% (95%CI: 28.5-42.6%) to 74.7% (66.3-81.6%) in the unadjusted model (p < 0.001), and from 35.1% (26.3-45.1%) to 73.9% (66.7-79.9%) in the adjusted model (p < 0.001). Factors associated with operative management for ASBO included admission to a surgical service (OR 2.8 [95%CI: 2.4-3.2], p < 0.001), congenital intestinal and/or rotational anomaly (OR 2.5 [2.1-3.1], p < 0.001), diagnostic workup including advanced abdominal imaging (OR 1.7 [1.5-1.9], p < 0.001), non-emergent admission status (OR 1.5 [1.3-1.8], p < 0.001), and increasing number of complex chronic comorbidities (OR 1.3 [1.2-1.4], p < 0.001). Factors associated with nonoperative management for ASBO included increased hospital-specific annual ASBO volume (OR 0.98 [95%CI: 0.97-0.99], p = 0.002), older age (OR 0.97 [0.96-0.98], p < 0.001), public insurance (OR 0.87 [0.78-0.96], p = 0.008), and presence of coinciding non-intestinal congenital anomalies, neurologic/neuromuscular disease, and/or medical technology dependence (OR 0.57 [95%CI: 0.47-0.68], p < 0.001).

CONCLUSIONS

Rates of surgical intervention for ASBO vary significantly across tertiary children's hospitals in the United States. The variability was independent of patient and hospital characteristics and is likely due to practice variation.

LEVEL OF EVIDENCE

III.

Localized Controlled Release of Kynurenic Acid Encapsulated in Synthetic Polymer Reduces Implant-Induced Dermal Fibrosis

Excessive fibrosis following surgical procedures is a challenging condition with serious consequences and no effective preventive or therapeutic option. Our group has previously shown the anti-fibrotic effect of kynurenic acid (KynA) in vitro and as topical cream formulations or nanofiber dressings in open wounds. Here, we hypothesized that the implantation of a controlled release drug delivery system loaded with KynA in a wound bed can prevent fibrosis in a closed wound. Poly (lactic-co-glycolic acid) (PLGA), and a diblock copolymer, methoxy polyethylene glycol-block-poly (D, L-lactide) (MePEG-b-PDLLA), were used for the fabrication of microspheres which were evaluated for their characteristics, encapsulation efficiency, in vitro release profile, and in vivo efficacy for reduction of fibrosis. The optimized formulation exhibited high encapsulation efficiency (>80%), low initial burst release (~10%), and a delayed, gradual release of KynA. In vivo evaluation of the fabricated microspheres in the PVA model of wound healing revealed that KynA microspheres effectively reduced collagen deposition inside and around PVA sponges and α-smooth muscle actin expression after 66 days. Our results showed that KynA can be efficiently encapsulated in PLGA microspheres and its controlled release in vivo reduces fibrotic tissue formation, suggesting a novel therapeutic option for the prevention or treatment of post-surgical fibrosis.

Preoperative prediction of inadvertent enterotomy during adhesive small bowel obstruction surgery using combination of CT features

OBJECTIVES

The purpose of this study was to identify the preoperative CT features that are associated with inadvertent enterotomy (IE) during adhesive small bowel obstruction (ASBO) surgery.

METHODS

From January 2015 to December 2019, all patients with ASBO who underwent an abdominal CT were reviewed. Abdominal CT were retrospectively reviewed by two radiologists with a consensus read in case of disagreement. IE during ASBO surgery was retrospectively recorded. Univariate and multivariate analyses of CT features associated with IE were performed and a simple CT score was built to stratify the risk of IE. This score was validated in an independent retrospective cohort. Abdominal CT of the validation cohort was reviewed by a third independent reader.

RESULTS

Among the 368 patients with ASBO during the study period, 169 were surgically treated, including 129 ASBO for single adhesive band and 40 for matted adhesions. Among these, there were 47 IE. By multivariate analysis, angulation of the transitional zone (OR = 4.19, 95% CI [1.10-18.09]), diffuse intestinal adhesions (OR = 4.87, 95% CI [1.37-19.76]), a fat notch sign (OR = 0.32, 95% CI [0.12-0.85]), and mesenteric haziness (OR = 0.13, 95% CI [0.03-0.48]) were independently associated with inadvertent enterotomy occurrence. The simple CT score built to stratify risk of IE displayed an AUC of 0.85 (95% CI [0.80-0.90]) in the study sample and 0.88 (95% CI [0.80-0.96]) in the validation cohort.

CONCLUSION

A simple preoperative CT score is able to inform the surgeon about a high risk of IE and therefore influence the surgical procedure.

KEY POINTS

• In this retrospective study of 169 patients undergoing abdominal surgery for adhesive small bowel obstruction, 47 (28%) inadvertent enterotomy occurred. • A simple preoperative CT score enables accurate stratification of inadvertent enterotomy risk (area under the curve 0.85). • By multivariable analysis, diffuse intestinal adhesions and angulation of the transitional zone were predictive of inadvertent enterotomy occurrence.

Cytochalasin B Modulates Nanomechanical Patterning and Fate in Human Adipose-Derived Stem Cells

Cytoskeletal proteins provide architectural and signaling cues within cells. They are able to reorganize themselves in response to mechanical forces, converting the stimuli received into specific cellular responses. Thus, the cytoskeleton influences cell shape, proliferation, and even differentiation. In particular, the cytoskeleton affects the fate of mesenchymal stem cells (MSCs), which are highly attractive candidates for cell therapy approaches due to their capacity for self-renewal and multi-lineage differentiation. Cytochalasin B (CB), a cyto-permeable mycotoxin, is able to inhibit the formation of actin microfilaments, resulting in direct effects on cell biological properties. Here, we investigated for the first time the effects of different concentrations of CB (0.1–10 μM) on human adipose-derived stem cells (hASCs) both after 24 h (h) of CB treatment and 24 h after CB wash-out. CB influenced the metabolism, proliferation, and morphology of hASCs in a dose-dependent manner, in association with progressive disorganization of actin microfilaments. Furthermore, the removal of CB highlighted the ability of cells to restore their cytoskeletal organization. Finally, atomic force microscopy (AFM) revealed that cytoskeletal changes induced by CB modulated the viscoelastic properties of hASCs, influencing their stiffness and viscosity, thereby affecting adipogenic fate.

Deletion of Calponin 2 Reduces the Formation of Postoperative Peritoneal Adhesions

Aim of the study: Postoperative peritoneal adhesions are a common cause of morbidity after surgery, resulting in multiple complications. Macrophage-mediated inflammation and myofibroblast differentiation after tissue injury play central roles in the pathogenesis and progression of adhesion formation. Calponin 2 is an actin cytoskeleton regulatory protein in endothelial cells, macrophages and fibroblasts that are key players in the development of fibrosis. Deletion of calponin 2 has been shown to attenuate inflammatory arthritis, atherosclerosis and fibrocalcification of the aortic valves. The present study investigated the effect of calponin 2 deletion on attenuating the formation of peritoneal adhesions in a mouse model for potential use as a new therapeutic target.Materials and methods: Sterile surgical procedures under general anesthesia were used on paired wild type (WT) and calponin 2 knockout (KO) mice to generate mild injury on the cecal and abdominal wall peritonea. Three and seven days post-operation, the mice were compared postmortem for the formation of peritoneal adhesions. Tissues at the adhesion sites were examined with histology and immunofluorescent studies for macrophage and myofibroblast activations.Results: Quantitative scoring demonstrated that calponin 2 KO mice developed significantly less postoperative peritoneal adhesions than that in WT mice. Calponin 2 deletion resulted in less infiltration of F4/80⁺ macrophages at the adhesion sites with less myofibroblast differentiation and collagen deposition than WT controls.Conclusions: The data show that deletion of calponin 2 effectively reduces postoperative peritoneal adhesion, presenting a novel molecular target for clinical prevention.

Infección temprana de la malla quirúrgica en herniorrafia incisional. Incidencia, factores de riesgo y desenlaces en más de 60.000 pacientes

Introducción. La infección de la malla en cirugía de reparación de hernias de pared abdominal es un desenlace pobre, asociado a un incremento en el riesgo de complicaciones. El objetivo del presente estudio fue analizar la incidencia, los factores asociados y desenlaces en pacientes llevados a herniorrafia incisional con malla con posterior diagnóstico de infección temprana. Métodos. Estudio de cohorte retrospectiva. Se utilizaron los datos de egresos hospitalarios de la National Inpatient Sample (NIS) de los Estados Unidos de América para identificar a todos los pacientes adultos llevados a herniorrafia incisional durante los años 2010 a 2015. Se utilizaron modelos de regresión logística bivariada y multivariada para evaluar los factores de riesgo en infección temprana de la malla, y finalmente, modelos de regresión logística y lineal, según el tipo de variable dependiente, de tipo stepwise forward para evaluar la asociación entre el diagnóstico de infección de malla y los desenlaces adversos. Resultados. En total se incluyeron 63.925 pacientes. La incidencia de infección temprana de la malla fue de 0,59 %, encontrando como factores asociados: comorbilidades (obesidad, desnutrición proteico calórica, anemia carencial y depresión), factores clínico-quirúrgicos (adherencias peritoneales, resección intestinal, cirugía laparoscópica y complicaciones no infecciosas de la herida) y administrativos o asistenciales. Conclusiones. La infección temprana, aunque infrecuente, se asocia con un aumento significativo en el riesgo de complicaciones. La optimización prequirúrgica con base en los factores de riesgo para este desenlace nefasto es un elemento clave para la reducción de la incidencia y mitigación del impacto de la infección en los pacientes con herniorrafía incisional con malla.

[Surgical approach for small bowel obstruction in the Russian Federation. National survey of surgeons]

OBJECTIVE

To study surgical approach for small bowel obstruction (SBO) regarding national and international guidelines.

MATERIAL AND METHODS

Considering literature data, national and international guidelines and clinical practice, we have formulated 15 questions regarding surgical approach for non-neoplastic SBO. Questions were sent by e-mail to the members of the Russian Society of Surgeons. Survey lasted 60 days. We used the program that provides the respondent with the possibility of visual control of survey results. Survey results were compared with national and international clinical guidelines, Russian- and English-language scientific publications. Restriction of the number of votes >1 and identification of respondents were not provided by the program. There was no reward for survey. A summary is provided on the main issues.

RESULTS

There were 557 respondents (3.0% of surgeons in the Russian Federation). We obtained 481-620 answers for each question.

CONCLUSION

This study is a valuable tool for primary assessment of current surgical practice for SBO in the Russian Federation. Study design did not imply conclusions on the optimal strategy based on opinions of majority of respondents. According to our survey, a significant number of respondents use the treatment strategy that differ from clinical guidelines. Their approach is based on their own clinical experience and local guidelines for the treatment of SBO. Less than half of the answers matched to national clinical guidelines, less than 10% - to the WSES guidelines. Despite the formal coincidence of some statements in national clinical guidelines and English-language recommendations, significant nonconformities require scientific discussion.

Extraperitoneal Laparoscopic Radical Cystectomy With Preservation of Fertility for the Treatment of Ewing Sarcoma: The First Report of a Reliable Surgical Method

OBJECTIVE

To improve the complications of traditional laparoscopic radical cystectomy (LRC), a novel technique of extraperitoneal laparoscopic radical cystectomy (ELRC) with preservation of fertility was described.

MATERIALS AND METHODS

Selected patients with bladder cancer were treated with the ELRC technique. The seminal vesicles and the vas deferens were preserved. Patient's perioperative conditions, tumor prognosis, and follow-up data were analyzed retrospectively.

RESULTS

We successfully completed ELRC surgery in dozens of patients. The orthotopic ileal neobladder was placed in the extraperitoneal area, completely preserving the peritoneum. The postoperative complications caused by postoperative peritoneal loss were reduced. Moreover, the perioperative period was strictly managed with the concept of enhanced recovery after surgery (ERAS). We described the operation process in detail through a typical case of a child. All patients were free of complication at short-term follow-up, and reported satisfied sexual function with normal erections.

CONCLUSION

The ELRC technique has benefits in terms of decreased ileus, reoperation rates, hospital stay, ease of management of urinary leaks, and improves the patient quality of life. ELRC is also an oncologically safe approach with excellent significant functional outcomes in carefully selected transitional cell carcinoma (TCC) or non-TCC patients who expect to maintain sexual function and fertility, especially for young patients. In addition, more patient groups and longer follow-ups are needed to further understand the safety and practicality of the ELRC technology.

Prevention of post-surgical adhesion bands by local administration of frankincense n-hexane extract

Background

and purpose: The formation of postoperative intra-abdominal adhesion band formation may lead to severe complications. This study aimed to evaluate the preventive effect of local administration of frankincense n-hexane extract (FHE) on the formation of postsurgical adhesion bands.

Materials and methods

FHE was extracted from the resin of a Boswellia sacra tree and its components were identified by gas chromatography-mass spectrometry (GC-MS). In an animal model, the expression levels of TNF-α and TGF-β1 cytokines after application of FHE were assessed to check the inflammatory and fibrotic cues, respectively.

Results

Following FHE compound analysis, in vivo experiments demonstrated that intraoperative local administration of FHE resulted in the prevention of adhesion band formation. The adhesion grades in the FHE-treated group were significantly lower than those in the negative control (NC) and the positive control (Interceed). The infiltration of inflammatory cells observed by histopathology revealed a significant anti-inflammatory potential of FHE. Furthermore, the gene expression results proved that significant suppression of TNF-α and TGF-β1 was responsible for its antiadhesion properties.

Conclusions

The study reported the potential of FHE as an ointment for the prevention of adhesion bands.

•

Recognition of compounds with anti-inflammatory, antifibrotic activities in FHE using gas chromatography-mass spectrometry.

•

The avoidance of adhesion bands formation, in vivo following intraoperative local administration of FHE.

•

A notable anti-inflammatory potential of FHE detected by histopathology results.

•

Approving the regulation of TNF-α and TGF-β1 involved in the intra-abdomen adhesion preventive properties of FHE.

Genetic and Epidemiological Similarities, and Differences Between Postoperative Intraperitoneal Adhesion Development and Other Benign Fibro-proliferative Disorders

Intraperitoneal adhesions complicate over half of abdominal-pelvic surgeries with immediate, short, and long-term sequelae of major healthcare concern. The pathogenesis of adhesion development is similar to the pathogenesis of wound healing in all tissues, which if unchecked result in production of fibrotic conditions. Given the similarities, we explore the published literature to highlight the similarities in the pathogenesis of intra-abdominal adhesion development (IPAD) and other fibrotic diseases such as keloids, endometriosis, uterine fibroids, bronchopulmonary dysplasia, and pulmonary, intraperitoneal, and retroperitoneal fibrosis. Following a literature search using PubMed database for all relevant English language articles up to November 2020, we reviewed relevant articles addressing the genetic and epidemiological similarities and differences in the pathogenesis and pathobiology of fibrotic diseases. We found genetic and epidemiological similarities and differences between the pathobiology of postoperative IPAD and other diseases that involve altered fibroblast-derived cells. We also found several genes and single nucleotide polymorphisms that are up- or downregulated and whose products directly or indirectly increase the propensity for postoperative adhesion development and other fibrotic diseases. An understanding of the similarities in pathophysiology of adhesion development and other fibrotic diseases contributes to a greater understanding of IPAD and these disease processes. At a very fundamental level, blocking changes in the expression or function of genes necessary for the transformation of normal to altered fibroblasts may curtail adhesion formation and other fibrotic disease since this is a prerequisite for their development. Similarly, applying measures to induce apoptosis of altered fibroblast may do the same; however, apoptosis should be at a desired level to simultaneously ameliorate development of fibrotic diseases while allowing for normal healing. Scientists may use such information to develop pharmacologic interventions for those most at risk for developing these fibrotic conditions.

Radiologist Checklist for Selecting Patients to Undergo PIPAC (Pressurized IntraPeritoneal Aerosol Chemotherapy)

Peritoneal carcinomatosis frequently occurs in advanced gastrointestinal and gynecological cancers. As factors such as poor drug uptake and distribution cause chemotherapy to be less effective, alternative therapies have been explored. Introduced in 2013, PIPAC (pressurized intraperitoneal aerosol chemotherapy) uses aerosolized chemotherapeutics sprayed into the patient’s peritoneal cavity using a laparoscopic approach. Despite the literature showing encouraging data regarding the tolerability and efficacy of PIPAC, there is a lack of articles on the role that imaging plays in selecting patients suitable for PIPAC. The aim of this study is to combine literature-based evidence and clinical experience to provide information able to support training radiologists, as well as experienced radiologists interested in innovative therapies.

Diagnosis and management of small bowel obstruction in virgin abdomen: a WSES position paper

Background

Small bowel obstruction (SBO) is a common surgical emergency, causing high morbidity and healthcare costs. The majority of SBOs are caused by adhesions that result from previous surgeries. Bowel obstruction, however, also occurs in patients without previous operation or known pathology, a so called virgin abdomen. It is unknown if small bowel obstruction in the virgin abdomen (SBO-VA) can be managed according to the same principles as other cases of small bowel obstruction. The aim of this position paper is to evaluate the available evidence on etiology and management of small bowel obstruction in the virgin abdomen.

Methods

This is a narrative review with scoping aspects. Clinical topics covered in this review include epidemiology and etiology of SBO-VA, diagnosis and imaging, initial assessment, the role of surgical management in SBO-VA, and the role of non-operative management in SBO-VA.

Results

Our scoping search revealed seven original studies reporting original patient data related to SBO-VA. All the included studies are retrospective cohorts, with populations ranging between 44 and 103 patients with SBO-VA. Adhesions were found to be the cause of the obstruction in approximately half of the reported cases of SBO-VA. A relatively high number of cases of SBO-VA were managed surgically with studies reporting 39–83%. However, in cases where a trial of non-operative management was started, this was generally successful.

Conclusion

The data available suggest that etiology and treatment results for patients with SBO-VA are largely comparable to the results in patients with SBO after previous abdominal surgery. We therefore propose that patients with a virgin abdomen could be treated according to existing guidelines for SBO and adhesive small bowel obstruction.

The Influence of Prior Abdominal Surgery on Robot-Assisted Partial Nephrectomy

Background

We evaluated the influence of prior abdominal surgery on perioperative outcomes in patients who underwent robot-assisted partial nephrectomy in initial Japanese series.

Methods

We reviewed patients with small renal tumors who underwent robot-assisted partial nephrectomy from October 2011 to September 2020 at our institution. Patients with prior abdominal surgery were compared with those without prior surgery based on perioperative outcomes. The chi-square test and Mann-Whitney U test were used for statistical analyses of variables.

Results

Of 156 patients who underwent robot-assisted partial nephrectomy, 90 (58%) had no prior abdominal surgery, whereas 66 patients (42%) underwent prior abdominal surgery. No significant differences in perioperative outcomes were observed between with and without prior abdominal surgery groups. In transperitoneal approach robot-assisted partial nephrectomy, 31 patients (80.4%) had prior abdominal surgery. Trocar insertion time in the with prior abdominal surgery group took longer than the without prior abdominal surgery group (32 vs. 28.5 min, P = 0.031). No significant difference was observed in the conversion rate between the two groups (P = 0.556).

Conclusion

Robot-assisted partial nephrectomy appears to be a safe approach for patients with prior abdominal surgery. In transperitoneal approach robot-assisted partial nephrectomy with prior abdominal surgery, trocar insertion time was longer, but no significant differences were found in other outcomes. Transperitoneal approach robot-assisted partial nephrectomy is thus considered a safe procedure for patients with prior abdominal surgery.

Salvia miltiorrhiza hydroalcoholic extract inhibits postoperative peritoneal adhesions in rats

Background

One of the most prevalent postoperative complications is believed to be intra-abdominal peritoneal adhesions, which is followed by several complications. Several adhesion prevention products have been examined, yet none of them were found to be completely effective. The current research is conducted to evaluate the beneficial effects of Salvia miltiorrhiza hydroalcoholic extract in inhibiting postoperative peritoneal adhesions in rats.

Methods

Forty rats were randomly classified into five equal groups (n = 8): 1) the normal group did not undergo surgical operations, 2) the control group in which the adhesion was induced, and which did not receive any treatment, 3) distilled water group that received distilled water, and 4,5) treatment groups treated with 1 and 5% of Salvia miltiorrhiza hydroalcoholic extract. The rats were euthanized 14 days following the surgery and the macroscopic score, the microscopic score of granulomatous inflammation and granulation tissue formation, IHC markers (vimentin, CD31, IL-1β, COX-2, and iNOS), and oxidative stress biomarkers (MDA, GPx, CAT, and TAC) were assessed in the experimental groups of the study.

Results

The difference between the control group and other groups for the adhesions macroscopic score, microscopic score, IHC markers, and oxidative stress biomarkers was significant (p < 0.05). Distilled water had no protective effect on the formation of peritoneal adhesions. Salvia miltiorrhiza treatment in two different doses significantly reduced macroscopic and microscopic scores, MDA concentration, Vimentin, IL-1β, COX-2, and iNOS compared to the control group (p < 0.05). The levels of GPx, CAT, and TAC in the treatment groups increased significantly compared with the control group (p < 0.05). Our findings revealed that a higher dose of Salvia miltiorrhiza was more effective in reducing peritoneal adhesions, proinflammatory and mesenchymal cell markers, and oxidative stress.

Conclusions

Salvia miltiorrhiza extract, owing to its strong antioxidant and anti-inflammatory properties, could effectively reduce peritoneal adhesions. Therefore, Salvia miltiorrhiza is recommended to be used as an effective anti-peritoneal post-operative adhesive agent.

Carboxymethyl Cellulose, Pluronic, and Pullulan-Based Compositions Efficiently Enhance Antiadhesion and Tissue Regeneration Properties without Using Any Drug Molecules

Pharmacological-based treatment approaches have been used over time to prevent postlaparotomy adhesion. However, the rapid elimination of therapeutics from the peritoneum, and their unwanted side effects, easy flow from the wound site by gravity, and low therapeutic efficacy increase the urgent need for the next generation of antiadhesion agents. This article represents the development of biocompatible and biodegradable antiadhesion agents that consist of carboxymethyl cellulose (CMC) and pullulan with three different types of physical characteristics such as the solution type (ST), film type (FT), and thermosensitive type (TST). These antiadhesion agents that contain no drugs exhibit excellent physical characteristics and superior stability over 30 days in the operative sites without any toxicity and side effects that make the compositions strong candidates as novel antiadhesion agents. Also, the proposed samples reveal superior antiadhesion and tissue regeneration properties in Sprague-Dawley (SD) rats after surgery over Medicurtain. Medicurtain effectively prevented postlaparotomy adhesion in ∼42% of experimental animals, whereas ST 2.25-10, ST 2.5-5, ST 2.5-10, FT 20, and TST 1.5 were effective in 100% of animals. Thus, we believe these antiadhesion agents could be promising to reduce adhesion-related complications during and post-surgical operations and deserve consideration for further study for clinical purposes.

Double-layered Nanofibrous Patch for Prevention of Anastomotic Leakage and Peritoneal Adhesions, Experimental Study

BACKGROUND/AIM

Anastomotic leakage is a feared complication in colorectal surgery. Postoperative peritoneal adhesions can also cause life-threatening conditions. Nanofibrous materials showed their pro-healing properties in various studies. The aim of the study was to evaluate the impact of double-layered nanofibrous materials on anastomotic healing and peritoneal adhesions formation.

MATERIALS AND METHODS

Two versions of double-layered materials from polycaprolactone and polyvinyl alcohol were applied on defective anastomosis on the small intestine of healthy pigs. The control group remained with uncovered defect. Tissue specimens were subjected to histological analysis and adhesion scoring after 3 weeks of observation.

RESULTS

The wound healing was inferior in the experimental groups, however, no anastomotic leakage was observed and the applied material always kept covering the defect. The extent of adhesions was larger in the experimental groups.

CONCLUSION

Nanofibrous materials may prevent anastomotic leakage but delay healing.

Evaluation of an octyl group-modified Alaska pollock gelatin-based surgical sealant for prevention of postoperative adhesion

Postoperative adhesion can lead to an increase in the number of surgeries required, longer operation times, and high medical costs, resulting in the quality of life of the patient being lowered. To address these clinical problems, we developed a surgical sealant with anti-adhesion properties for the prevention of postoperative adhesion following application to the large intestine surface. The developed sealant was composed of octyl (C8) group-modified Alaska pollock-derived gelatin (C8-ApGltn) and a poly(ethylene)glycol-based 4-armed crosslinker (4S-PEG) (C8-ApGltn/4S-PEG sealant). Hydrophobic modification of the ApGltn molecule with C8 groups effectively enhanced both the burst strength on the large intestine surface and the bulk modulus. An in vitro anti-adhesion test indicated that cured C8-ApGltn/4S-PEG sealant adhered to the large intestine surface showed low adhesive strength compared with commercial anti-adhesion film. Besides, cured C8-ApGltn/4S-PEG sealant effectively inhibited albumin permeation and penetration of L929 fibroblasts. In vivo experiments using a rat peritoneal anti-adhesion model showed that C8-ApGltn/4S-PEG sealant acted as a sealing barrier on the target cecum surface and also provided an anti-adhesion barrier to prevent postoperative adhesion between the peritoneum and cecum. C8-ApGltn/4S-PEG sealant showed sufficient cytocompatibility and biodegradability and therefore has potential for use in gastroenterological surgery.

Fouling-resistant zwitterionic polymers for complete prevention of postoperative adhesion

Postoperative adhesions are most common issues for almost any types of abdominal and pelvic surgery, leading to adverse consequences. Pharmacological treatments and physical barrier devices are two main approaches to address postoperative adhesions but can only alleviate or reduce adhesions to some extent. There is an urgent need for a reliable approach to completely prevent postoperative adhesions and to significantly improve the clinical outcomes, which, however, is unmet with current technologies. Here we report that by applying a viscous, cream-like yet injectable zwitterionic polymer solution to the traumatized surface, postoperative adhesion was completely and reliably prevented in three clinically relevant but increasingly challenging models in rats. The success rate of full prevention is over 93% among 42 animals tested, which is a major leap in antiadhesion performance. Clinically used Interceed film can hardly prevent the adhesion in any of these models. Unlike current antiadhesion materials serving solely as physical barriers, the "nonfouling" zwitterionic polymer functioned as a protective layer for antiadhesion applications with the inherent benefit of resisting protein/cell adhesions. The nonfouling nature of the polymer prevented the absorption of fibronectins and fibroblasts, which contribute to the initial and late-stage development of the adhesion, respectively. This is the key working mechanism that differentiated our "complete prevention" approach from current underperforming antiadhesion materials. This work implies a safe, effective, and convenient way to fully prevent postoperative adhesions suffered by current surgical patients.

The anti-adhesive effect of anti-VEGF agents in experimental models: A systematic review

Adhesions constitute a major problem in abdominal-pelvic and thoracic surgery with significant impact in the postoperative quality of life and healthcare services utilization. Adhesiogenesis is the result of increased fibrin formation, impaired fibrinolysis, angiogenesis, and fibrosis. Despite the recent advancements, the ideal anti-adhesive agent remains to be determined. To this end, we performed a comprehensive literature search in PubMed, EMBASE, and Scopus databases to identify studies investigating the antiadhesive role of anti-VEGF agents in peritoneal, pleural, and pericardial experimental adhesion models. Fifteen studies were eligible for inclusion with a total population of 602 animals (334 rats, 180 rabbits, and 88 mice). The majority of included studies (11/15) used bevacizumab, while three studies used other anti-VEGF antibodies and one study used an anti-VEGFR-antibody. A rat model was used in nine studies, while rabbit (n = 3) or mouse (n = 3) models were used less frequently. Eleven studies used peritoneal models, three studies used pleural models, and one study used a pericardial model. The scales (n = 12) and interval (Range: 1-42 days) used for the evaluation of adhesions varied between the studies. All studies demonstrated a significant decrease in adhesion scores between the anti-VEGF and control groups up to 42 days postprocedure. VEGF blockade resulted in decreased fibrosis in four out of five studies that used peritoneal models, while the effect on pleural models depended on the pleurodesis agent and was significant between 7 and 28 days. The effect of anti-VEGF agents on anastomosis integrity depends on the dose and the model that is used (inconclusive results).Current data support the anti-adhesive role of Anti-VEGF agents in all three serosal surfaces up to 6 weeks postprocedure. Further studies are needed to confirm the anti-adhesive role of anti-VEGF agents in pleural and pericardial adhesion experimental models and investigate any effect on anastomosis integrity in peritoneal models.

The potential association between metabolic syndrome and risk of post-surgical adhesion

Metabolic syndrome (MetS) is defined by the clustering of several associated with a group of disorders that include: obesity, dyslipidemia, hypertension, and insulin resistance. The incidence of MetS is increasing globally around the world. Indeed the rates of different types of surgery in older or younger patients with Mets are increasing and they are exposed to a wide range of operations including abdominal, pelvic, urologic, or any invasive procedures. Post-surgical adhesion is a common problem and is a challenge for the surgeon. Despite many studies on its pathogenesis, there remain many un-answered questions about it, for example why certain tissues and patients are more at higher risk of post-surgical adhesions. Many studies have suggested that MetS is associated with up-regulating molecular mechanisms leading to chronic inflammation and hypercoagulability. In this review, we discuss some of the molecular mechanisms by MetS may enhance post-surgical adhesion, and particularly regarding those involved in coagulation and inflammation.

Injury Characteristics and Outcomes of Patients With Inflammatory Bowel Disease After Trauma: A Propensity Score Matched Analysis

BACKGROUND

The clinical course of patients with inflammatory bowel disease (IBD) after trauma is largely unknown. We sought to compare the clinical course of patients with IBD to those without.

METHODS

We conducted a retrospective case-control study of adult patients admitted to a level-1 trauma center from January 1, 2008, through October 1, 2015. Seventy-five patients with IBD were identified. Cases were matched to controls by age, sex, injury severity, and mechanism using 4:1 propensity score-matching analysis. Injury characteristics, clinical course, and infectious and noninfectious complications were compared using bivariate and multivariate analysis.

RESULTS

Participants had a mean age of 56 years and mean injury severity score of 15. Of the 75 cases, 44% had ulcerative colitis, 44% had Crohn's disease, and 12% had undetermined type. More cases were on an immunosuppressant (19% vs 2%, P < 0.01) or steroids (8% vs 2%, P = 0.02) on admission compared with controls. More cases had prior abdominal surgery (P = 0.01). Cases had fewer brain injuries (P = 0.02) and higher admission Glasgow Coma Scale (P < 0.01) but required more neurosurgical intervention (P = 0.03). Cases required more orthopedic surgeries (P < 0.01) and more pain management consultations (P = 0.04). In multivariable analysis, IBD was associated with increased odds of operative intervention, pain management consultation, venous thromboembolism, and longer hospital stay (P < 0.05). Patients on immunosuppressants had increased odds of requiring surgery (P = 0.04), particularly orthopedic surgery (P < 0.01).

CONCLUSIONS

Baseline factors associated with inflammatory bowel disease may place patients at higher risk for surgery and complications after trauma.

Peritoneal adhesions do not increase intra-operative organ injury or adverse neonatal outcomes during a repeated cesarean delivery

PURPOSE

To examine whether the presence of peritoneal adhesions at the second cesarean delivery (CD), attributable to the first CD, are associated with maternal intra-operative organ injury and adverse neonatal outcomes.

METHODS

A retrospective cohort study was conducted, comparing severe maternal intra-operative organ injury and adverse neonatal outcomes, between women with and without peritoneal adhesions. All women with two CDs during the follow-up period were included. Women with adhesions diagnosed during the first CD, history of other abdominal or pelvic surgery, pelvic infection or pelvic inflammatory disease, endometriosis, uterine Mullerian anomalies and newborns with known chromosomal or structural abnormalities were excluded, resulting in 7925 women. Intra-operative peritoneal organ injury was defined as a composite of bladder injury, ureteral injury, small bowel injury or hysterectomy. The examined adverse neonatal outcomes were low 1 and 5 min Apgar scores, intrapartum death (IPD) and postpartum death (PPD). Multivariate logistic regression was performed.

RESULTS

Peritoneal adhesions at the second CD, attributable to the first CD were diagnosed in 32.6% of patients (n = 2581). The presence of peritoneal adhesions was not found to be independently associated with intra-operative organ injury nor with 5 min Apgar scores, IPD and PPD. Second CDs complicated with adhesions were found to be associated with low (< 7) 1 min Apgar scores (adjusted OR 1.38, CI 1.20-1.58, p < 0.001).

CONCLUSION

Adhesions attributable to a previous CD do not seem to increase the risk for intra-operative organ injury and adverse neonatal outcomes. These findings may assist in reassuring patients who are facing a second CD.

Biomaterials to Prevent Post-Operative Adhesion

Surgery is performed to treat various diseases. During the process, the surgical site is healed through self-healing after surgery. Post-operative or tissue adhesion caused by unnecessary contact with the surgical site occurs during the normal healing process. In addition, it has been frequently found in patients who have undergone surgery, and severe adhesion can cause chronic pain and various complications. Therefore, anti-adhesion barriers have been developed using multiple biomaterials to prevent post-operative adhesion. Typically, anti-adhesion barriers are manufactured and sold in numerous forms, such as gels, solutions, and films, but there are no products that can completely prevent post-operative adhesion. These products are generally applied over the surgical site to physically block adhesion to other sites (organs). Many studies have recently been conducted to increase the anti-adhesion effects through various strategies. This article reviews recent research trends in anti-adhesion barriers.

Dual dynamically crosslinked thermosensitive hydrogel with self-fixing as a postoperative anti-adhesion barrier

Tissue adhesion is a severe postoperative complication. Various strategies have been developed to minimize postoperative adhesion, but the clinical efficacy is still far from satisfactory. Herein, we present a dual dynamically crosslinked hydrogel to serve as a physical postoperative anti-adhesion barrier. The hydrogel was generated by dynamic chemical oxime bonding from alkoxyamine-terminated Pluronic F127 (AOP127) and oxidized hyaluronic acid (OHA), as well as hydrophobic association of AOP127. Rheological analysis demonstrated that the hydrogel exhibits temperature sensitivity. At 37 °C, it shows much higher modulus and higher stability than the Pluronic F127 hydrogel. Hemolytic assays suggested that the hydrogel undergoes low hemolysis. In addition, it exhibited anti-adhesion to blood cells in blood cell adhesion tests. It also showed an anti-attachment effect to fibroblasts and biocompatibility in vitro cell studies. Macroscopic evaluation and lap-shear tests revealed that the hydrogel has a moderate adhesive capacity to tissue, which is important for self-fixation. A rat model of sidewall defect-bowel abrasion was established to evaluate the anti-adhesion effect in vivo. The gross observation and pathological analysis revealed a significant reduction in postoperative peritoneal adhesion in the AOP127/OHA hydrogel-treated group than those treated with normal saline or Pluronic F127 hydrogel. Hence, the dual dynamically crosslinked hydrogel with self-fixable capacity may be suitable as a physical barrier for postoperative adhesion prevention. STATEMENT OF SIGNIFICANCE: Despite the development of numerous postoperative anti-adhesion barriers, their anti-adhesion efficacy is still limited in clinical trials due to poor tissue adhesion and rapid clearance from injured areas. Herein, we have developed a dual dynamic crosslinked hydrogel, generated by dynamic oxime bonds and hydrophobic interactions. The hydrogel is temperature-sensitive and demonstrates moderate tissue adhesion capacity, which allows for self-fixation when applied to defects. The introduction of dynamic covalent bonds improves the stability of the hydrogel. Moreover, the hydrogel not only displays appropriate hemocompatibility, cytocompatibility and anti-adhesion of blood cells and fibroblasts, but it also effectively contributes to preventing postoperative peritoneal adhesions in vivo. Hence, this dual dynamic crosslinked hydrogel may have potential applications as a physical barrier in clinical practice.

A Comparative Analysis between Laparoscopic and Open Adhesiolysis at a Tertiary Care Center

Laparotomy has been the favored approach regarding surgical management of small bowel obstruction (SBO); however, laparoscopy may offer improved outcomes. Patients undergoing laparoscopic lysis of adhesions (LOA) at our institution for SBO will have lower postoperative morbidity and 30-day mortality. Patients undergoing LOA at our institution, from 2000 to 2011, were reviewed. Categorical data were analyzed with χ2or Fisher's exact tests. Continuous data were analyzed with Student's t test or Wilcoxon rank sum. One hundred two (38 laparoscopic, 64 open) LOA cases were selected. Perioperative contamination and conservative management were higher in the open group. Open cases had a greater incidence of intensive care unit (ICU) admissions and longer length of stay. Stratified analysis determined a strong association between perioperative contamination and a higher incidence of ICU admission, perioperative contamination and longer LOS, and conservative management and longer LOS. Finally, patient outcome did not differ between those treated by surgeons trained in minimally invasive surgery (MIS) compared with those not trained in MIS. Careful consideration of surgical approach and timing is called for in all patients with SBO; however, whenever possible, laparoscopic preference should be given to most patients in an expeditious fashion irrespective of MIS training.

Safety and efficacy of transperitoneal laparoscopic nephron sparing surgery in patients with previous abdominal surgery

OBJECTIVE

The aim of this study is to assess the safety and feasibility of the transperitoneal laparoscopic approach during nephron sparing surgery in patients with previous abdominal surgery.

PATIENTS AND METHODS

We retrospectively analyzed patients undergoing transperitoneal laparoscopic partial nephrectomy for renal masses. All patients had received a diagnosis of cT1a renal exophytic mass (⩽5 cm). Patients were divided into two groups, those with and without previous abdominal surgery. Patients with solitary kidney or major previous abdominal surgery were excluded in this study. The operative time, estimated blood loss, length of stay, surgical complications, and positive surgical margins were recorded to compare outcomes among two groups.

RESULTS

Of the 157 patients who were included in our study, 71 (45.3%) had a history of abdominal surgery (Group 1), while the remaining 86 (54.7%) had not (Group 2). Cholecystectomy was the most common previous surgery performed near the renal fossa. Patients with previous abdominal surgery experienced increased operative time (111.5 vs 83.2 min; p = 0.001). However, no statistically significant difference was found in estimated blood loss (122.1 vs 114.4 mL; p = 0.363), length of stay (4.1 vs 3.8 days; p = 0.465), rate of conversion to open surgery (2.8% vs 2.3%; p = 0.234), and rate of complications (p = 0.121). However, operative time (p = 0.003) and length of stay (p < 0.001) were greater in patients with versus those without previous open cholecystectomy.

CONCLUSION

Our results suggest that laparoscopic partial nephrectomy after minor previous abdominal surgery is safe and feasible in selected patients affected by renal masses with low nephrometry score. However, previous cholecystectomy results in an increased risk of conversion to open surgery and longer hospital stay in patients undergoing right laparoscopic partial nephrectomy.