Postoperative Abdominal Adhesions: Clinical Significance and Advances in Prevention and Management

A functional PVA aerogel-based membrane obtaining sutureability through modified electrospinning technology and achieving promising anti-adhesion effect after cardiac surgery

Pericardial barrier destruction, inflammatory cell infiltration, and fibrous tissue hyperplasia, trigger adhesions after cardiac surgery. There are few anti-adhesion materials that are both functional and sutureable for pericardial reconstruction. Besides, a few studies have reported on the mechanism of preventing pericardial adhesion. Herein, a functional barrier membrane with sutureability was developed via a modified electrospinning method. It was composed of poly(l-lactide-co-caprolactone) (PLCL) nanofibers, poly(vinyl alcohol) (PVA) aerogel, and melatonin, named PPMT. The PPMT had a special microstructure manifested as a staggered arrangement of nanofibers on the surface and a layered macroporous aerogel structure in a cross-section. Besides providing the porosity and hydrophilicity obtained from PVA, the structure also had suitable mechanical properties for stitching due to the addition of PLCL nanofibers. Furthermore, it inhibited the proliferation of fibroblasts by suppressing the activation of Fas and P53, and achieved anti-inflammatory effects by affecting the activity of inflammatory cells and reducing the release of pro-inflammatory factors, such as interleukin 8 (IL-8) and tumor necrosis factor α (TNF-α). Finally, in vivo transplantation showed that it up-regulated the expression of matrix metalloproteinase-1 (MMP1) and tissue inhibitor of metalloproteinase-1 (TIMP1), and down-regulated the expression of Vinculin and transforming growth factor β (TGF-β) in the myocardium, thereby reducing the formation of adhesions. Collectively, these results demonstrate a great potential of PPMT membrane for practical application to anti-adhesion.

•

A functional PVA aerogel-based membrane (PPMT) obtained sutureability through modified electrospinning technology.

•

The primary mechanism to anti-adhesion of PPMT membrane was explored.

•

Promising anti-adhesion effect of PPMT membrane was accomplished in pericardium reconstruction in rabbit.

The effect of N-acetyl-l-cysteine on inflammation after intraperitoneal mesh placement in a potentially contaminated environment: Experimental study in the rat

BACKGROUND

The use of prosthetic meshes in abdominal wall reconstruction is a well-established approach; however, in certain cases where a bowel resection coexists its application is disputed. Any underlying inflammatory process may augment adhesion formation which is a major postoperative complication. In this animal study, our aim was to investigate the effect of N-acetyl-l-cysteine (NAC) on adhesion formation and the expression of inflammatory markers when a mesh was used in a clean or a potentially contaminated environment.

METHODS

Sixty male Wistar rats were randomly and equally allocated in 3 groups: A, B and C. Animals in all groups underwent laparotomy, a prosthetic mesh was placed and chemoprophylaxis with ciprofloxacin was administered. In groups B and C an enterectomy was also performed. NAC was injected intraperitoneally in group C. Adhesion formation, IL-1a, IL-6, TNF-a and histological data including fibrosis, neutrophils' infiltration and neovascularization were assessed. Mesh samples were sent for cultivation.

RESULTS

Adhesion formation was significantly less and inflammation markers were also lower in group C compared to group B (p<0.05). Histological findings were significant for greater fibrosis, neutrophils' infiltration and neovascularization in group B compared to both group A and C. Regarding mesh cultures, more specimens were tested positive in group B (p <0.05). Outcomes between group A and C did not differ.

CONCLUSION

NAC effectively ameliorated adhesion formation and inflammation in a potentially septic environment where a prosthetic mesh was placed.

The prevention of postoperative port-site adhesion following single-port access (SPA) laparoscopic surgeries

ABSTRACT

No studies have examined the issue of intraabdominal port-site adhesion following single-port access (SPA) laparoscopic surgeries. The purpose of the present study was to investigate the clinical effects of temperature-sensitive adhesion barrier solution in preventing periumbilical adhesion in SPA laparoscopy. This was a prospective, single-arm study in which patients were given GUARDIX-SGTM after SPA laparoscopic surgery for benign gynecologic diseases. One gram of GUARDIX-SGTM was applied on the abdominal viscera just below the umbilical port site and adjacent abdominal wall prior to fascia closure. The primary endpoint was the incidence of postoperative adhesion evaluated by visceral sliding technique through transabdominal sonography after three months. Between June 2019 and March 2020, a total of 37 healthy patients without any history of previous abdominal surgery received SPA laparoscopic surgery by a single surgeon. No postoperative complications such as wound dehiscence or surgical site infection occurred during the follow-up period of three months. No postoperative adhesion around the umbilicus was noted in all 37 patients. The mean visceral movement measured by transabdominal sonography during maximal respiration was 4.9 cm (4.9 ± 1.9 cm). Using an adhesion barrier around the port site prior to fascia closure prevents postoperative adhesion in benign SPA laparoscopic gynecologic surgery.

Endostatin in fibrosis and as a potential candidate of anti-fibrotic therapy

Fibrotic diseases pose significant clinical challenges due to their broadness and complexity. Thus, a better understanding of fibrogenesis and the development of more effective treatments is imperative. Recent evidence suggests a significant antifibrotic potential of an endogenous glycoprotein, endostatin. While endostatin has been widely studied for its role as an anticancer adjuvant by inhibiting tumor angiogenesis, its possible implication in fibrosis remains largely unclear. Here, we review the role of endostatin in various cellular processes and highlight its antifibrotic activity. We hypothesize that endostatin conveys a homeostatic function in the process of fibrosis by regulating (a) TGF-β1 and its downstream signaling; (b) RhoA/ROCK pathway; (c) NF-κB signaling pathway; (d) expression of EGR-1; (e) PDGF/PDGFR pathway; (f) autophagy-related pathways; (g) pathways associated with cell proliferation and apoptosis. Finally, we propose a schematic model of the antifibrotic roles and mechanisms of endostatin; also, we outline future research directions of endostatin and aim to present a potential therapeutic approach for fibrosis.

Automatic implantable cardioverter defibrillator (AICD) within the abdomen as a cause of adhesive small bowel obstruction (ASBO): a case report

Adhesive small bowel obstruction (ASBO) is commonly caused by intra-abdominal adhesions, usually from prior surgery. Conservative management is the mainstay of treatment, with adhesiolysis required for non-resolving obstruction. An unusual patient presentation of ASBO is presented here, where the cause is proposed as an automatic implantable cardioverter defibrillator (AICD) within the abdomen. Although the patient had several presentations of ASBO successfully treated with conservative management, a non-resolving obstruction required surgical management. At laparotomy, the AICD was found to be in close association with extensive matted adhesions to adjacent small bowel. Adhesiolysis was performed, with the AICD implanted in a subrectus pocket. The patient had an uncomplicated recovery, and at review 6 weeks following the operation was found to have a normal bowel habit with nil further episodes concerning for obstruction. This case highlights the importance of non-classical risk factors being a possible cause of ASBO.

Establishment of a Rabbit Intervertebral Disc Degeneration Model by Percutaneous Posterolateral Puncturing of Lumbar Discs Under Local Anesthesia

OBJECTIVE

An anterior approach is applied to establish the majority of rabbit intervertebral disc degeneration (IDD) models in current studies. However, for research on disc repair via biomaterial implantation and tissue engineering, this traditional model establishment method has many shortcomings, such as the risk of general anesthesia, unnecessary tissue damage, and the influence of scar formation on the visual field for secondary implantation surgery. The aim of this study was to report a modified method of establishing an IDD model by applying percutaneous posterolateral puncturing for rabbit lumbar disc surgery under local anesthesia.

METHODS

We built a rabbit model of IDD by percutaneous posterolateral annulus fibrosus puncturing (AFP) (with or without nucleus pulposus aspiration [NPA]) under local anesthesia. Then, we analyzed the outcome after 12 weeks via magnetic resonance images, disc height changes, and disc histologic grades determined from morphologic observation and histologic analyses (hematoxylin and eosin and safranin-O staining and type II collagen expression analysis).

RESULTS

The IDD model was successfully built based on both AFP and AFP/NPA, as demonstrated by the results of magnetic resonance imaging index, morphologic, and histologic analyses. Both methods can successfully produce an IDD model after 12 weeks. However, we found that the addition of NPA significantly enhanced the modeling results.

CONCLUSIONS

Our results show that percutaneous posterolateral AFP/NPA of rabbit lumbar discs under local anesthesia is a minimally invasive, safe and reproducible method of establishing an IDD model. The posterolateral surgical approach is especially suitable for disc regeneration studies that require secondary biomaterial implantation via an anterior approach after the IDD model is established.

Accuracy of third trimester ultrasound in predicting neonatal birthweight in patients with inflammatory bowel disease

OBJECTIVE

To evaluate the accuracy of third trimester ultrasound in predicting birthweight in patients with inflammatory bowel disease (IBD) using the gestation-adjusted projection (GAP) method.

STUDY DESIGN

Retrospective cohort study including pregnant patients with IBD who had third trimester ultrasounds and delivered at a single institution from 2012 to 2017. Controls included pregnant patients without IBD seen during the study period with third trimester ultrasounds. Correlation plots of GAP birthweight and actual birthweight (AB) were created for IBD-positive cases, IBD-negative controls, and IBD-positive cases with and without prior abdominal surgery. GAP predicted birthweight error was calculated for cases and controls. Univariable linear regression models estimated the association between predicted birthweight and AB. Multivariable linear regression models estimated the association between GAP birthweight and AB adjusting for age, BMI, race, and IBD status.

RESULTS

320 patients were included (172 cases and 148 controls). Cases were more likely to be older (p < 0.001), white (p < 0.001), and have a lower BMI (p = 0.001). Correlation plots of GAP birthweight and AB showed linear correlations in cases (Spearman ρ = 0.81), controls (ρ = 0.74), cases with (p = 0.78) and without prior surgery (ρ = 0.83). GAP birthweight was significantly associated with AB in controls and cases in univariable linear regression models (β = 0.85, standard error = 0.04, p < 0.001; β = 0.90, standard error = 0.06, p < 0.001, respectively). No significant difference was found between the parameter estimates of the two models (p = 0.47). GAP birthweight remained significantly associated with AB in a multivariable linear regression model (β = 0.86, standard error = 0.03, p < 0.001). There were no significant differences between GAP predicted birthweight error between controls and cases (APE 11% vs 10% respectively, p = 0.56) and between cases without and with prior surgery (APE 10% vs 11%, p = 0.7).

CONCLUSION

The accuracy of fetal biometry in the third trimester for predicting actual birthweight was equivalent between patients with and without IBD and those with prior abdominal surgery.

Anti-Adhesive Effect of Porous Polylactide Film in Rats

Excessive adhesion between tissues on a significant area can cause the development of disorders, cosmetic problems, and ileus. Methods for preventing adhesion include the use of drugs and anti-adhesion barriers for physical blocking. In this study, the adhesion prevention effect of polylactide film in porous form was analyzed. A porous polylactide film was manufactured using a molecular weight of at least 100,000. To generate porosity, 98% methylene chloride and 95% ethyl alcohol were used as solvents. The thickness, surface, and internal pore shape of film were investigated. The crystal structures and melting temperature of film were measured. In the rat model, the presence and severity of adhesion were then analyzed. The thickness of the film ranged from 10 to 20 µm. The surface of the film contained pores with diameters of less than 10 µm. Partial crystallinity appeared from 15° to 20°, but the structure was amorphous overall. In the rat cecum abrasion model, adhesion occurred in 3 of the 13 rats in the polylactide experimental group, representing a 23.1% incidence rate. There were statistically significant differences in the severity of adhesion. The use of porous polylactide films can reduce the incidence of adhesion.

Biodegradable Zwitterionic Cream Gel for Effective Prevention of Postoperative Adhesion

Postoperative peritoneal adhesions were frequent complications for almost any types of abdominal and pelvic surgery. This led to numerous medical problems and huge financial burden to the patients. Current anti-adhesion strategies focused mostly on physical barriers including films and hydrogels. However, they can only alleviate or reduce adhesions to certain level and their applying processes were far from ideal. This work reported the development of a biodegradable zwitterionic cream gel presenting a series of characters for an idea anti-adhesion material, including unique injectable yet malleable and self-supporting properties, which enabled an instant topical application, no curing, waiting or suturing, no hemostasis requirement, protein/cell resistance and biodegradability. The cream gel showed a major advancement in anti-adhesion efficacy by completely and reliably preventing a primary and a more severe recurrent adhesion in rat models.

Association Between Statin Use at the Time of Intra-abdominal Surgery and Postoperative Adhesion-Related Complications and Small-Bowel Obstruction

IMPORTANCE

Adhesion-related complications (ARCs), including small-bowel obstruction, are common complications of intra-abdominal surgery. Statins, which have antifibrotic pleiotropic effects, inhibit adhesion formation in murine models but have not been assessed in humans.

OBJECTIVE

To assess whether statin use at the time of intra-abdominal surgery is associated with a reduction in ARCs.

DESIGN, SETTING, AND PARTICIPANTS

These 2 separate retrospective cohort studies (The Health Improvement Network [THIN] and Optum's Clinformatics Data Mart [Optum]) compared adults receiving statins with those not receiving statins at the time of intra-abdominal surgery. Individuals undergoing intra-abdominal surgery from January 1, 1996, to December 31, 2013, in the United Kingdom and from January 1, 2000, to December 31, 2016, in the US were included in the study. Those with obstructive events before surgery or a history of inflammatory bowel disease were excluded. Data analysis was performed from September 1, 2012, to November 24, 2020.

EXPOSURE

The primary exposure was statin use at the time of surgery.

MAIN OUTCOMES AND MEASURES

The primary outcome was ARCs, defined as small-bowel obstruction or need for adhesiolysis, occurring after surgery. Sensitivity analyses included statin use preceding but not concurrent with surgery, fibrate use, and angiotensin-converting enzyme inhibitor use. All analyses were adjusted for age, sex, and conditions associated with microvascular disease, such as hypertension, hyperlipidemia, obesity, and tobacco use; surgical approach and site; and diagnosis of a malignant tumor.

RESULTS

A total of 148 601 individuals met the inclusion criteria for THIN (mean [SD] age, 49.6 [17.7] years; 70.1% female) and 1 188 217 for Optum (mean [SD] age, 48.2 [16.4] years; 72.6% female). A total of 2060 participants (1.4%) experienced an ARC in THIN and 54 136 (4.6%) in Optum. Statin use at the time of surgery was associated with decreased risk of ARCs (THIN: adjusted hazard ratio [HR], 0.81; 95% CI, 0.71-0.92; Optum: adjusted HR, 0.92; 95% CI, 0.90-0.95). Similar associations were appreciated between statins and small-bowel obstruction (THIN: adjusted HR, 0.80; 95% CI, 0.70-0.92; Optum: adjusted HR, 0.88; 95% CI, 0.85-0.91).

CONCLUSIONS AND RELEVANCE

This study's findings suggest that, among individuals in 2 separate cohorts undergoing intra-abdominal surgery, statin use may be associated with a reduced risk of postoperative ARCs. Statins may represent an inexpensive, well-tolerated pharmacologic option for preventing ARCs.

Probabilistic Risk Assessment of Prophylactic Surgery Before Extended-Duration Spaceflight

Introduction. Prophylactic surgery before spaceflight may eliminate the risk of appendicitis and cholecystitis in astronauts on deep space missions. However, even minimally invasive surgery increases the risk of small bowel obstruction (SBO). Probabilistic risk assessment (PRA) is a method that can be used to estimate the benefits and risks of prophylactic surgery. Methods. Risks of appendicitis and cholecystitis during a 2.5-year Mars mission are compared to the risk of SBO after laparoscopic removal of the appendix, gallbladder, or both. A PRA model using Monte Carlo methodology was used to forecast the risks. Results. Prophylactic appendectomy and cholecystectomy combined, conferred an increased probability of medical evacuation (pEVAC) due to SBO as compared to the no surgery group. A slightly higher probability for the loss of crew life (pLOCL) was found in the no surgery group when compared to the cases in which either prophylactic appendectomy alone, or appendectomy plus cholecystectomy are performed. Discussion. The need for medical evacuation can be viewed as a potential risk for death in the context of a space mission where evacuation is not possible. Because of the higher pEVAC due to SBO and relatively small benefit in the reduction of pLOCL in the prophylactic surgery groups, this analysis does not support the prophylactic removal of appendix and/or gallbladder for spaceflight. Future advances in surgical or medical technique or mission medical capabilities may change these results. This work demonstrates the utility of PRA in providing quantitative answers to "what if" questions where limited information is available.

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.

Management of giant presacral schwannoma. Clinical series and literature review

PURPOSE

Presacral schwannomas are rare tumors. Due to their benign nature and slow growth, these tumors are often giant and become difficult to treat. Their removal is a surgical challenge with different strategies reported in the literature. This study presents the consecutives cases of presacral schwannomas operated on in our institution, our surgical strategy and literature review.

METHODS

This retrospective study includes all consecutive patients operated on for a pre-sacral schwannoma in our department between 2006 and 2019, i.e. 6 patients. We report clinical features, pre and post-operative imaging, surgical data and post-operative outcomes.

RESULTS

All patients had symptoms before surgery (constipation, dysuria, radicular or lower back pain) with an average duration of 7.4 months. All patients underwent an MRI and a CT scan before the surgery. Five patients had type III schwannoma according to Klimo classification and one patient had a type II. The average size was 504,9 cm³ (range 53,1-1495,4). All the patients were operated on by an anterior approach in a double team with an mean duration of 246 min. Intraoperative bleeding was less than 500 ml for 4 patients, 2 patients had significant bleeding (2700 and 2900 mL). Excision was total or subtotal in all cases. One patient had an intraoperative complication (air embolism). Follow up at 3 months was excellent with a disappearance of symptoms for all patients except one patient who retained constipation. One patient had a late complication (bowel obstruction due to tissue adhesions). At last follow-up after phone interview, no patient had clinical symptoms that could suggest a recurrence.

CONCLUSION

The anterior approach with a double surgical team is a great option for the treatment of presacral schwannoma. Combined with adequate preoperative imaging and intraoperative stimulation, it reduces the risk of intra and postoperative complications.

"BAX602" in Preventing Surgical Adhesion after Extracorporeal Ventricular Assist Device Implantation for Refractory Congestive Heart Failure: Study Protocol for a Multicenter Randomized Clinical Trial

BACKGROUND

The high surgical risk in redo cardiac surgery is largely attributed to adhesions around the epicardium and the great vessels. BAX602 is an adhesion prevention reagent composed of two synthetic polyethylene glycols. Spraying BAX602 over the epicardium and the great vessels reportedly contributes to adhesion prevention after pediatric cardiac surgery. The present study aims to evaluate the safety and effectiveness of BAX602 spray in patients undergoing extracorporeal ventricular assist device implantation surgery to treat refractory congestive heart failure.

METHODS AND DESIGN

This investigator-initiated, multicenter, pivotal, two-arm, open-label, randomized trial will include a total of 30 patients. The primary outcome measure is the severity of adhesions, which will be evaluated during re-sternotomy surgery performed 2-12 weeks after the primary extracorporeal ventricular assist device implantation surgery. The adhesion severity will be evaluated at five predefined sites using a four-grade adhesion evaluation score (0 = no adhesion; 1 = filmy and avascular adhesion; 2 = dense/vascular adhesion; 3 = cohesive adhesion). This measure will be summarized in two ways to evaluate the effect of BAX602: (1) the total score of the severity of adhesions at all five sites (ranging from 0 to 15), and (2) the total number of sites with dense/vascular or cohesive adhesions (ranging from 0 to 5).

ETHICS AND DISSEMINATION

The study findings will be disseminated at regional, national, and international conferences and through peer-reviewed scientific journals.

TRIAL REGISTRATION

The trial was registered in the UMIN Clinical Trials Registry (UMIN-CTR: UMIN000038998) on 6 January 2020.

Outcome of Laparoscopic Adhesiolysis in Infertile Patients with Pelvic Adhesions Following Cesarean Delivery: A Randomized Clinical Trial

OBJECTIVES

To evaluate results of laparoscopic adhesiolysis in patients with post cesarean infertility regards restoration of the fertility and achievement of pregnancy. To identify a group of patients who should primarily be offered laparoscopic adhesiolysis and those who should be treated by IVF.

DESIGN

Randomized prospective clinical trial MATERIALS AND METHODS: 184 patients with secondary infertility diagnosed to have periadnexal and pelvic adhesions, were randomly allocated into two groups: group I (92 cases) treated by laparoscopic adhesiolysis and group II (92 cases) who treated for a year by controlled ovarian stimulation and IUI up to 3 trials. Diagnostic work-up of infertility was carried out denoting normal semen, patent both tubes at HSG, and ovulatory at ovulation testing with normal hormonal profile. The outcomes, cumulative pregnancy rates calculated for each group after one year.

RESULTS

According to the adhesions, the patients classified into 4 groups: 8 cases inoperable, 43 cases with mild type adhesions, 26 cases with moderate type adhesions, and 5 cases with severe type adhesions. The patients followed up postoperatively for year. Overall pregnancy rate 54.35 %. For patients with mild adhesions 76.7%, for patients with moderate adhesions 61.5%, and for patients with severe adhesions 20%. Complications present in (1.57%), cost is (125.7-180.9 $). Over all pregnancy rate was 11.96% in group (II) CONCLUSIONS: laparoscopic adhesiolysis is the method of choice for dealing with mild to moderate periadnexal adhesions after C.S. The pregnancy outcome after lysis of severe periadnexal adhesions is poor. So, such patients are best treated by IVF.

Adhesive small bowel obstruction after appendectomy in children - Laparoscopic versus open approach

BACKGROUND

The aims of this study were to compare the incidence of small bowel obstruction (SBO) requiring laparotomy after laparoscopic appendectomy (LA) and open appendectomy (OA) in children and to identify risk factors for SBO.

METHODS

Medical records of patients who underwent appendectomy from 2000 to 2014 at our department of Pediatric Surgery were reviewed. Risk factors were analyzed using Cox proportional hazard regression.

RESULTS

Totally 619 out of 840 patients were included. OA was performed in 474 (76.6%), LA in 130 patients (21%), and 15 (2.4%) were converted from LA to OA. Age, sex and proportion of perforated appendicitis were comparable in the LA and OA groups. Median follow-up time was 11.4 years (2.6-18.4). The incidence of SBO after LA was 1.5%, after OA 1.9% and in the converted group 6.7% (p = 0.3650). There were no significant differences in the incidence of postoperative intraabdominal abscess, wound infection or length of stay between LA and OA. Perforation and postoperative intra-abdominal abscess were identified as risk factors with 9.03 (p < 0.001) and 6.98 (p = 0.004) times higher risk of SBO, respectively.

CONCLUSIONS

The risk for SBO after appendectomy in children was significantly related to perforated appendicitis and postoperative intra-abdominal abscess and not to the surgical approach.

LEVEL OF EVIDENCE

Level III.

Peritoneal adhesions: Occurrence, prevention and experimental models

Peritoneal adhesions (PA) are a postoperative syndrome with high incidence rate, which can cause chronic abdominal pain, intestinal obstruction, and female infertility. Previous studies have identified that PA are caused by a disordered feedback of blood coagulation, inflammation, and fibrinolysis. Monocytes, macrophages, fibroblasts, and mesothelial cells are involved in this process, and secreted signaling molecules, such as tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), tissue plasminogen activator (tPA), and type 1 plasminogen activator inhibitor (PAI-1), play a key role in PA development. There have been many attempts to prevent PA formation by anti-PA drugs, barriers, and other therapeutic methods, but their effectiveness has not been widely accepted. Treatment by biomaterial-based barriers is believed to be the most promising method to prevent PA formation in recent years. In this review, the pathogenesis, treatment approaches, and animal models of PA are summarized and discussed to understand the challenges faced in the biomaterial-based anti-PA treatments.

Endoscopic Treatment of a Twisted Small Bowel Obstruction after Laparoscopic Proximal Gastrectomy with Double Tract Reconstruction

This paper reports a case of a twisted small bowel obstruction in a 74-year-old man that occurred after a double tract reconstruction (DTR) in a laparoscopic proximal gastrectomy (PG) for early gastric cancer. The patient had inadequate oral intake and reflux symptoms for 10 days after discharge. Imaging analysis revealed a narrowed small bowel with twists between the esophagojejunostomy and gastrojejunostomy sites. A fully covered stent was placed in the narrowed small bowel for 2 weeks. The patient was then discharged after stent removal without any dietary problems. The authors' experience shows that twisted small bowel after a DTR in PG can be treated by endoscopy.

Berberine prevents primary peritoneal adhesion and adhesion reformation by directly inhibiting TIMP-1

Peritoneal adhesions are fibrous tissues that tether organs to one another or to the peritoneal wall and represent the major cause of postsurgical morbidity. Enterolysis at repeat surgeries induces adhesion reformation that is more difficult to prevent than primary adhesion. Here we studied the preventive effects of different approaches of berberine treatment for primary adhesion, and its effects on adhesion reformation compared to Interceed. We found the primary adhesion was remarkably prevented by berberine through intraperitoneal injection 30 min before abrasive surgery (pre-berberine) or direct addition into injured cecum immediately after the surgery (inter-berberine). Rats with adhesion reformation had a more deteriorative collagen accumulation and tissue injury in abrasive sites than rats with primary adhesion. The dysregulated TIMP-1/MMP balance was observed in patients after surgery, as well as adhesion tissues from primary adhesion or adhesion reformation rats. Inter-berberine treatment had a better effect for adhesion reformation prevention than Interceed. Berberine promoted the activation of MMP-3 and MMP-8 by directly blocking TIMP-1 activation core, which was reversed by TIMP-1 overexpression in fibroblasts. In conclusion, this study suggests berberine as a reasonable approach for preventing primary adhesion formation and adhesion reformation.

Prevention of Intra-abdominal Adhesions by Electrical Stimulation

The study investigated the ability of transdermal electric stimulation to prevent the formation of intra-abdominal adhesions in the combination with Seprafilm^® (anti-adhesive agent). One hundred and twenty-eight (128) rabbits were subjected to a surgical procedure to simulate the adhesion processes. After the simulation, the animals were divided into 4 groups (32 animals each), depending on the application of the methods of prevention: (1) control group (no anti-adhesives or electro-stimulation) (CG); (2) comparison group (applications of Seprafilm^®) (SF); (3) comparison group 2 (transdermal electric stimulation of the abdominal muscles) TES; (4) group (transdermal electric stimulation + Seprafilm^®) (TES + SF). We observed that the application of the Seprafilm^® alone led to a significant decrease in the adhesive process compared to the control group (CG) (p < 0.01). The adhesion process in the group underwent transdermal electrical stimulation (TES) was significantly lower compared to the Seprafilm^® group (SF) (p ≤ 0.05). The results demonstrated a significant decrease in the adhesion processes in the SF + TES group on days 1, 3, 7 and 14 in comparison with the CG group (p = 0.001), SF group (p = 0.001) and TES group (p = 0.01) group of animals. This study showed the efficacy of transdermal electrical muscle stimulation for the prevention of intra-abdominal adhesions. Moreover, the combination of Seprafilm^® anti-adhesion agent and electrical muscle stimulation resulted in the complete absence of adhesions. Our findings indicate the potential of such strategy for further clinical application.

Thermal stimuli-responsive hyaluronic acid loaded cellulose based physical hydrogel for post-surgical de novo peritoneal adhesion prevention

Effective strategies for post-surgical adhesion prevention have increasingly focused on injectable adhesion barriers due to their minimal invasiveness and wider applicability. In this study, a thermo-reversible hydrogel was developed by combining high molecular weight hyaluronic acid (HA) at various concentrations (0.05, 0.25, and 0.45% w/v) with tempo-oxidized nanocellulose (TOCN), methyl cellulose (MC) and polyethylene glycol (PEG) for anti-adhesion application. The hydrogel preparation time was short and did not require any chemical modification. TOCN ensured the mechanical stability of the hydrogel. MC confirmed thermo-sensitive feature. Higher amounts of HA increased the rate of hydrogel degradation. The HA 0.25 hydrogel was free-flowing, injectable at ambient temperature, capable of faster (40 ± 2 s), and reversible sol-gel (4 °C-37 °C) transition. A rat side-wall cecum abrasion model was used to confirm the complete de novo adhesion prevention efficacy of optimized HA 0.25 hydrogel, where the scratched abdominal wall of animals treated with HA 0.25 hydrogel healed after 14 days. During in vivo experiment, PEG in the hydrogel played a crucial role in adhesion prevention by minimizing friction between the surgical site and nearby organs. In a nutshell, HA 0.25 hydrogel, fabricated without crosslinking agent, is a potential candidate for tissue adhesion prevention strategies.

Adhesion reformation and the limited translational value of experiments with adhesion barriers: A systematic review and meta-analysis of animal models

Today, 40-66% of elective procedures in general surgery are reoperations. During reoperations, the need for adhesiolysis results in increased operative time and a more complicated convalescence. In pre-clinical evaluation, adhesion barriers are tested for their efficacy in preventing 'de novo' adhesion formation, However, it is unknown to which extent barriers are tested for prevention of adhesion reformation. The aim of this systematic review and meta-analysis is to assess the efficacy of commercially available adhesion barriers and laparoscopic adhesiolysis in preventing adhesion reformation in animal models. Pubmed and EMBASE were searched for studies which assessed peritoneal adhesion reformation after a standardized peritoneal injury (in the absence of an intra-peritoneal mesh), and reported the incidence of adhesions, or an adhesion score as outcome. Ninety-three studies were included. No study met the criteria for low risk of bias. None of the commercially available adhesion barriers significantly reduced the incidence of adhesion reformation. Three commercially available adhesion barriers reduced the adhesion score of reformed adhesions, namely Seprafilm (SMD 1.38[95% CI]; p < 0.01), PEG (SMD 2.08[95% CI]; p < 0.01) and Icodextrin (SMD 1.85[95% CI]; p < 0.01). There was no difference between laparoscopic or open adhesiolysis with regard to the incidence of adhesion reformation (RR 1.14[95% CI]; p ≥ 0.05) or the adhesion score (SMD 0.92[95% CI]; p ≥ 0.05). Neither currently commercially available adhesion barriers, nor laparoscopic adhesiolysis without using an adhesion barrier, reduces the incidence of adhesion reformation in animal models. The methodological quality of animal studies is poor.

HuoXueTongFu Formula Alleviates Intraperitoneal Adhesion by Regulating Macrophage Polarization and the SOCS/JAK2/STAT/PPAR-γ Signalling Pathway

Intraperitoneal adhesion is a common complication after abdominal surgery, which seriously affects the quality of life of patients. HuoXueTongFu Formula (HXTF) plays an important role in the prevention and treatment of intraperitoneal adhesions. However, the molecular-related mechanisms are still not fully known. In this study, the model of Intrapetitoneal adhesion was established by cecum abrasion and treated with HXTF for one week. RAW264.7 cells were given LPS, IFN-γ, IL-4, HXTF-medicated serum, and PPAR-γ agonist/antagonist, respectively. Histopathology, flow cytometry, ELISA, real-time PCR, and Western blotting were used to further detect the related protein, M1/M2 polarization tendency, and PPAR-γ nuclear translocation. The deposition of collagen fibres reduced in the local area of rats after the operation with HXTF treatment. Similar to IL-4, HXTF induced a tendency for macrophages to polarize toward M2 and promoted peroxisome proliferator-activated receptor-gamma (PPAR-γ) nuclear translocation. Furthermore, the use of HXTF and PPAR-γ agonists downregulated macrophage M1 polarization-related factors IL-1, IL-6, and TNF-alpha and upregulated M2 polarization-related factors IL-4, IL-10, and TGF-beta 1. Meanwhile, the use of HXTF and PPAR-γ agonists downregulated the SOCS3/JAK2/STAT1 pathway and activated the SOCS1/STAT6/PPAR-γ pathway. These results show that HXTF may reduce intraperitoneal adhesion by inducing macrophage M2 polarization and regulating the SOCS/JAK2/STAT/PPAR-γ pathway.

Ligustrazine nanoparticles nano spray's activation on Nrf2/ARE pathway in oxidative stress injury in rats with postoperative abdominal adhesion

Background

Postoperative abdominal adhesions formation is considered a significant clinical entity implicating the healing process following major pelvic and abdominal surgery, with serious clinical complications and need for substantial health care expenditures. However, setting a physical barrier between the damage site and the neighboring tissues is a convenient and highly valid way to minimize or prevent peritoneal adhesions. The present experimental study evaluated the preventive effect of ligustrazine nanoparticles nano spray (LNNS) on postoperative abdominal adhesion in rats and explored its mechanism.

Methods

Sixty male Sprague Dawley (SD) rats were randomly divided into sham operation group, control group, sodium hyaluronate group and low, medium, and high dose LNNS groups. All groups were prepared with abdominal adhesion models except for the sham operation group. The models were made by opening the abdominal cavity to and filing the serosa in ileocecal junction. The abdominal cavity of rats in the sham operation group were only opened and sutured. The wound surface of rats in the sodium hyaluronate group, low, medium, and high dose LNNS groups were sprayed with sodium hyaluronate gel (0.5 mL/kg) and LNNS (2.5, 5, and 10 mL/kg). Rats in each group were sacrificed 7 days later. Degree of adhesion was evaluated by naked eyes and the pathological sections were scored afterwards. The collagen synthesis in adhesion tissues was detected by Masson's trichrome stain, and the activities of reactive oxygen species (ROS), nitric oxide (NO), superoxide dismutase (SOD) and malondialdehyde (MDA) in peritoneal fluid were detected with the method of chromogenic substrate. Levels of TNF-α and IL-1β in serum, and the protein levels of MCP-1 and MMP-9 in adhesion tissues were detected by ELISA and. immunohistochemistry respectively. RT-PCR and Western blot were utilized to identify the expression levels of Nrf2, heme-oxygenase-1, NQO1 mRNA and protein in adherent intestinal tissues.

Results

Compared with the control group, the incidence of postoperative abdominal adhesions decreased in the low, medium and high dose LNNS groups, while the expression of SOD in the peritoneal fluid significantly increased. The expression levels of ROS, MDA and NO were reduced remarkably (P<0.05), so were the expression levels of serum TNF-α and IL-1β (P<0.01) and the expression of MCP-1 protein in adhesion tissues. The MMP-9 protein expression, and Nrf2, heme-oxygenase-1, NQO1 mRNA and protein expressions increased.

Conclusions

LNNS with medium or high dose can significantly reduce the incidence of postoperative abdominal adhesions, the mechanism of which may be the activation of Nrf2/ARE pathway, resulting in the up-regulation of Nrf2, heme-oxygenase-1, NQO1 and mRNA expression, as well as the levels of TNF-α and IL-1β in peripheral blood and the expression of MCP-1 protein in adhesion tissues. Meanwhile, the content of MMP-9 protein in adhesion tissues were raised, and oxidative stress and inflammatory response are released.

Biomaterial Implants in Abdominal Wall Hernia Repair: A Review on the Importance of the Peritoneal Interface

Biomaterials have long been used to repair defects in the clinical setting, which has led to the development of a wide variety of new materials tailored to specific therapeutic purposes. The efficiency in the repair of the defect and the safety of the different materials employed are determined not only by the nature and structure of their components, but also by the anatomical site where they will be located. Biomaterial implantation into the abdominal cavity in the form of a surgical mesh, such as in the case of abdominal hernia repair, involves the contact between the foreign material and the peritoneum. This review summarizes the different biomaterials currently available in hernia mesh repair and provides insights into a series of peculiarities that must be addressed when designing the optimal mesh to be used in this interface.

Chinese Trauma Surgeon Association for management guidelines of vacuum sealing drainage application in abdominal surgeries-Update and systematic review

Vacuum sealing drainage (VSD) is frequently used in abdominal surgeries. However, relevant guidelines are rare. Chinese Trauma Surgeon Association organized a committee composed of 28 experts across China in July 2017, aiming to provide an evidence-based recommendation for the application of VSD in abdominal surgeries. Eleven questions regarding the use of VSD in abdominal surgeries were addressed: (1) which type of materials should be respectively chosen for the intraperitoneal cavity, retroperitoneal cavity and superficial incisions? (2) Can VSD be preventively used for a high-risk abdominal incision with primary suture? (3) Can VSD be used in severely contaminated/infected abdominal surgical sites? (4) Can VSD be used for temporary abdominal cavity closure under some special conditions such as severe abdominal trauma, infection, liver transplantation and intra-abdominal volume increment in abdominal compartment syndrome? (5) Can VSD be used in abdominal organ inflammation, injury, or postoperative drainage? (6) Can VSD be used in the treatment of intestinal fistula and pancreatic fistula? (7) Can VSD be used in the treatment of intra-abdominal and extra-peritoneal abscess? (8) Can VSD be used in the treatment of abdominal wall wounds, wound cavity, and defects? (9) Does VSD increase the risk of bleeding? (10) Does VSD increase the risk of intestinal wall injury? (11) Does VSD increase the risk of peritoneal adhesion? Focusing on these questions, evidence-based recommendations were given accordingly. VSD was strongly recommended regarding the questions 2-4. Weak recommendations were made regarding questions 1 and 5-11. Proper use of VSD in abdominal surgeries can lower the risk of infection in abdominal incisions with primary suture, treat severely contaminated/infected surgical sites and facilitate temporary abdominal cavity closure.

PLGA/PLCA casting and PLGA/PDPA electrospinning bilayer film for prevention of postoperative adhesion

Postoperative adhesion is a common complication and preventing adhesions during or immediately after operation is particularly important. The application of solid barrier materials represents the most successful clinical strategy to prevent postoperative adhesion. However, a simple physical barrier effect might be insufficient in preventing adhesion satisfactorily. Multilayered structures can be designed with an outer layer as the barrier and an inner layer to respond to relative drug release. In this article, bilayer film composed of a PLGA/PLCA casting layer as barrier and PLGA/PDPA electrospinning layer to respond to the release of anti-fibrosis drug l-Phe was designed and synthesized. The adhesion prevention effect of the above PLGA/PLCA/PDPA bilayer film was examined and compared with single PLGA/PLCA casting film and single PLGA/PDPA electrospinning film by applying rabbit sidewall defect-cecum abrasion model. As demonstrated by histological observation and immunohistochemical analysis, the bilayer film was the most effective of the three films in postoperative adhesion prevention in terms of both physical barrier effect and anti-fibrosis effect of the PDPA macromolecular prodrug. Besides anti-fibrosis effect, PDPA could also suppress excess proliferation of vascular endothelial cells and microvessel caused by long-term stimulation of implantation materials to the surrounding tissues. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2030-2039, 2019.

Efficacy and safety of laparoscopic splenectomy and esophagogastric devascularization for portal hypertension: A single-center experience

Many patients in China have portal hypertension secondary to liver cirrhosis. Splenectomy and devascularization have become an efficacious surgical procedure for portal hypertension, and has been recommended in China as the first choice for the treatment of portal hypertension for a long time. As a result of advances in laparoscopic equipment and techniques, splenectomy and esophagogastric devascularization have been carried out with laparoscope.From January 2012 to December 2017, 453 patients who were diagnosed with portal hypertension and serious gastroesophageal varices received surgical management in our institution. 250 patients chose laparoscopic splenectomy and esophagogastric devascularization and 203 underwent open splenectomy and esophagogastric devascularization.We retrospectively analyzed the perioperative data and follow-up data of these patients. The operation time of laparoscopic group was longer than open group (P ≤ .001). Intraoperative blood loss was less (P ≤ .001), the passing of flatus was earlier (P = .042), and postoperative hospital stay was shorter (P = .001) in the laparoscopic group. During postoperative follow-up of 4 to 75 months, the incidence of esophagogastric variceal rebleeding, encephalopathy, and secondary liver cancer showed no significant differences.Laparoscopic splenectomy and esophagogastric devascularization were safe and more effective than open surgery for portal hypertension and gastroesophageal varices.

Adhesion Prevention to Polypropylene Meshes Using Combined Icodextrin Four Percent and Dimetindene Maleate

BACKGROUND

The use of surgical meshes in ventral hernia repair has significantly reduced hernia recurrence rates. However, when placed intraperitoneally prosthetic materials can trigger the development of peritoneal adhesions. The present experimental study evaluated the combined icodextrin 4% and dimetindene maleate treatment in preventing peritoneal adhesion formation to polypropylene and titanium-coated polypropylene meshes.

MATERIALS AND METHODS

Sixty female white rabbits were divided into four groups. A 2 × 2 cm piece of mesh was fixed to intact peritoneum in all animals through a midline laparotomy. A lightweight polypropylene mesh was implanted in groups 1 and 2 and a titanium-coated polypropylene mesh in groups 3 and 4. Groups 2 and 4 were treated, intraoperatively, with intravenous dimetindene maleate (0.1 mg/kg) and intraperitoneal solution of icodextrin 4% (20 mL/kg) and for the next 6 d with dimetindene maleate intramuscularly. The observation period lasted 15 d. Adhesion scores, percentage of mesh affected surface, tissue hydroxyproline levels, and tissue histopathology were examined.

RESULTS

All animals in group 1 and 57% of animals in group 3 presented postoperative adhesions. The combination of antiadhesives significantly reduced the extent and severity of adhesions as well as the hydroxyproline levels in groups 2 and 4 compared with groups 1 and 3. On microscopic evaluation, animals in group 1 exhibited higher inflammation scores compared with group 2, whereas animals in groups 2 and 4 had better mesotheliazation compared with groups 1 and 3.

CONCLUSIONS

The combined administration of icodextrin 4% and dimetindene maleate reduces the extent and severity of adhesions and may be successfully used to prevent adhesion formation after mesh intraperitoneal placement.

Effect of statins on experimental postoperative adhesion: a systematic review and meta-analysis

Adhesion is a significant concern after surgery. Many researchers studied the anti-adhesive effect of statin, of which results were inconsistent. Thus, we purposed to perform a systematic review and meta-analysis to evaluate the effect of statins on postoperative adhesion in an experimental study. A comprehensive search was conducted using MEDLINE, EMBASE, and Google Scholar to identify animal studies that investigated the postoperative anti-adhesive effect of statins applied at the surgical area. Primary outcome measure was gross adhesion score. Secondary outcomes included microscopic adhesion score and tissue plasminogen activator (t-PA) activity. Totally, 298 rats from 9 animal studies (172 rats received statin therapy and 126 rats received placebo or no treatment) were included in the final analysis. The combined results showed that gross and microscopic adhesion scores were significantly lower in the statin group in comparison to the control group (standardized mean difference [SMD] = 1.65, 95% confidence interval [CI]: 1.02 to 2.28, P_chi² < 0.001, I² = 77.9%; SMD = 1.90, 95% CI: 1.10 to 2.79, P_chi² < 0.001, I² = 84.5%, respectively). However, there was no evidence of a difference in t-PA activity (SMD = -3.43, 95% CI: -7.95 to 1.09, P_chi² < 0.001, I² = 95.5%). In conclusion, statins were effective in preventing postoperative adhesion, as assessed based on gross and microscopic adhesion scores in rats.

Porous Polylactide Film Plus Atorvastatin-Loaded Thermogel as an Efficient Device for Peritoneal Adhesion Prevention

Peritoneal adhesion is a common postoperative complication that causes many kinds of organ dysfunctions. It can be minimized by the integration of physical isolation and pharmaceutical treatment. However, the gas permeability of traditional medical devices for adhesion prevention is not satisfactory, which increases the risk of infection and inflammation, thus facilitating the formation of peritoneal adhesion. In this study, a device of porous polylactide (PLA) film plus atorvastatin (ATV)-loaded thermogel was developed for peritoneal adhesion prevention. PLA film acted as a physical barrier to prevent the connection of fibrin bridges between the injured tissues and nearby normal organs. Simultaneously, ATV was released to achieve the antifibrin deposition and anti-inflammatory effect. The porous properties of PLA film and thermogel increased the gas permeability and further inhibited the inflammatory responses. The in vivo study demonstrated that the porous PLA film with ATV-loaded thermogel possessed excellent anti-inflammation ability and satisfactory antiadhesion capacity, indicating its great potential for clinical application.