Enhancement of soil aggregation and physical properties through fungal amendments under varying moisture conditions.

Soil structure and aggregation are crucial for soil functionality, particularly under drought conditions. Saprobic soil fungi, known for their resilience in low moisture conditions, are recognized for their influence on soil aggregate dynamics. In this study, we explored the potential of fungal amendments to enhance soil aggregation and hydrological properties across different moisture regimes. We used a selection of 29 fungal isolates, recovered from soils treated under drought conditions and varying in colony density and growth rate, for single-strain inoculation into sterilized soil microcosms under either low or high moisture (≤-0.96 and -0.03 MPa, respectively). After 8 weeks, we assessed soil aggregate formation and stability, along with soil properties such as soil water content, water hydrophobicity, sorptivity, total fungal biomass and water potential. Our findings indicate that fungal inoculation altered soil hydrological properties and improved soil aggregation, with effects varying based on the fungal strains and soil moisture levels. We found a positive correlation between fungal biomass and enhanced soil aggregate formation and stabilization, achieved by connecting soil particles via hyphae and modifying soil aggregate sorptivity. The improvement in soil water potential was observed only when the initial moisture level was not critical for fungal activity. Overall, our results highlight the potential of using fungal inoculation to improve the structure of agricultural soil under drought conditions, thereby introducing new possibilities for soil management in the context of climate change.

Heterogeneity in Spore Aggregation and Germination Results in Different Sized, Cooperative Microcolonies in an Aspergillus niger Culture.

The fungus Aspergillus niger is among the most abundant fungi in the world and is widely used as a cell factory for protein and metabolite production. This fungus forms asexual spores called conidia that are used for dispersal. Notably, part of the spores and germlings aggregate in an aqueous environment. The aggregated conidia/germlings give rise to large microcolonies, while the nonaggregated spores/germlings result in small microcolonies. Here, it is shown that small microcolonies release a larger variety and quantity of secreted proteins compared to large microcolonies. Yet, the secretome of large microcolonies has complementary cellulase activity with that of the small microcolonies. Also, large microcolonies are more resistant to heat and oxidative stress compared to small microcolonies, which is partly explained by the presence of nongerminated spores in the core of the large microcolonies. Together, it is proposed that heterogeneity in germination and aggregation has evolved to form a population of different sized A. niger microcolonies, thereby increasing stress survival and producing a meta-secretome more optimally suited to degrade complex substrates. IMPORTANCE Aspergillus niger can form microcolonies of different size due to partial aggregation of spores and germlings. So far, this heterogeneity was considered a negative trait by the industry. We here, however, show that heterogeneity in size within a population of microcolonies is beneficial for food degradation and stress survival. This functional heterogeneity is not only of interest for the industry to make blends of enzymes (e.g., for biofuel or bioplastic production) but could also play a role in nature for effective nutrient cycling and survival of the fungus.

Visualising long distance sugar transport in fungi using infrared fluorescence scanning imaging.

Mycelia of saprotrophic basidiomycetes can cover large areas in nature that are typified by their heterogeneous nutrient availability. This heterogeneity is overcome by long distance transport of nutrients within the hyphal network to sites where they are needed. It is therefore key to be able to study nutrient transport and its underlying mechanisms. An IRDye-conjugate was used for the first time for imaging transport in fungi. A method was set up for time-lapse, high spatial resolution infrared imaging of IRDye-labelled deoxyglucose (IRDye-DG) in Schizophyllum commune and Agaricus bisporus. Scanning imaging visualised the tracer in individual hyphae as well as deeper tissues in mushrooms (mm-cm depth). The advantage of using fluorescence scanning imaging of IRDye in contrast to radiolabelled tracers studies, is that a higher spatial resolution and higher sensitivity (244 fg/ml) can be obtained. Moreover, it has a large field of view (25 × 25 cm) compared to microscopy (µm-mm range), allowing relatively fast and detailed imaging of large dimension samples.

Single Cell Analysis and Sorting of Aspergillus fumigatus by Flow Cytometry.

Experimental results in fungal biology research are usually obtained as average measurements across whole populations of cells, whilst ignoring what is happening at the single cell level. Microscopy has allowed us to study single-cell behavior, but it has low throughput and cannot be used to select individual cells for downstream experiments. Here we present a method that allows for the analysis and selection of single fungal cells in high throughput by flow cytometry and fluorescence activated cell sorting (FACS), respectively. This protocol can be adapted for every fungal species that produces cells of up to 70 microns in diameter. After initial setting of the flow cytometry gates, which takes a single day, accurate single cell analysis and sorting can be performed. This method yields a throughput of thousands of cells per second. Selected cells can be subjected to downstream experiments to study single-cell behavior.

Cycling in degradation of organic polymers and uptake of nutrients by a litter-degrading fungus.

Wood and litter degrading fungi are the main decomposers of lignocellulose and thus play a key role in carbon cycling in nature. Here, we provide evidence for a novel lignocellulose degradation strategy employed by the litter degrading fungus Agaricus bisporus (known as the white button mushroom). Fusion of hyphae allows this fungus to synchronize the activity of its mycelium over large distances (50 cm). The synchronized activity has a 13-h interval that increases to 20 h before becoming irregular and it is associated with a 3.5-fold increase in respiration, while compost temperature increases up to 2°C. Transcriptomic analysis of this burst-like phenomenon supports a cyclic degradation of lignin, deconstruction of (hemi-) cellulose and microbial cell wall polymers, and uptake of degradation products during vegetative growth of A. bisporus. Cycling in expression of the ligninolytic system, of enzymes involved in saccharification, and of proteins involved in nutrient uptake is proposed to provide an efficient way for degradation of substrates such as litter.

Growth induced translocation effectively directs an amino acid analogue to developing zones in Agaricus bisporus.

The vegetative mycelium of Agaricus bisporus supplies developing white button mushrooms with water and nutrients. However, it is not yet known which part of the mycelium contributes to the feeding of the mushrooms and how this depends on growth conditions. Here we used photon counting scintillation imaging to track translocation of the 14C-radiolabeled metabolically inert amino acid analogue α-aminoisobutyric acid (14C-AIB). Translocation to the periphery of the mycelium was observed in actively growing vegetative mycelium with a velocity of up to 6.6 mm h-1, which was 30-fold higher than the growth rate. Furthermore, 14C-AIB translocated to neighboring colonies after fusion by anastomosis depending on the relative growth rate in these colonies. When mushrooms started to develop, translocation of 14C-AIB was redirected to the fruiting bodies via mycelium and hyphal cords. More abundant mycelial cord formation and a 5-fold higher rate of translocation was observed for cultures growing directionally from inoculum located at one side of the substrate, when compared to non-directional growth (inoculum mixed throughout the substrate). The maximum translocation distance was also greater (≥50 and 22 cm, respectively). In conclusion, 14C-AIB translocation switches between vegetative growth and towards developing mushrooms, especially via cords and when source-sink relationships change.

Cell Wall Composition Heterogeneity between Single Cells in Aspergillus fumigatus Leads to Heterogeneous Behavior during Antifungal Treatment and Phagocytosis.

Aspergillus fumigatus can cause a variety of lung diseases in immunocompromised patients, including life-threatening invasive aspergillosis. There are only three main classes of antifungal drugs currently used to treat aspergillosis, and antifungal resistance is increasing. Experimental results in fungal biology research are usually obtained as average measurements across whole populations while ignoring what is happening at the single cell level. In this study, we show that conidia with the same genetic background in the same cell population at a similar developmental stage show heterogeneity in their cell wall labeling at the single cell level. We present a rigorous statistical method, newly applied to quantify the level of cell heterogeneity, which allows for direct comparison of the heterogeneity observed between treatments. We show the extent of cell wall labeling heterogeneity in dormant conidia and how the level of heterogeneity changes during germination. The degree of heterogeneity is influenced by deletions of cell wall synthesizing genes and environmental conditions, including medium composition, method of inoculation, age of conidia, and the presence of antifungals. This heterogeneity results in subpopulations of germinating conidia with heterogeneous fitness to the antifungal caspofungin, which targets cell wall synthesis and heterogeneous sensitivity of dormant conidia to phagocytosis by macrophages.IMPORTANCE The fungus Aspergillus fumigatus can cause invasive lung diseases in immunocompromised patients resulting in high mortality. Treatment using antifungal compounds is often unsuccessful. Average population measurements hide what is happening at the individual cell level. We set out to test what impact individual differences between the cell walls of fungal conidia have on their behavior. We show that a population of cells having the same genetic background gives rise to subpopulations of cells that exhibit distinct behavior (phenotypic heterogeneity). This cell heterogeneity is dependent on the strain type, gene deletions, cell age, and environmental conditions. By looking at the individual cell level, we discovered subpopulations of cells that show differential fitness during antifungal treatment and uptake by immune cells.

Subpopulations of hyphae secrete proteins or resist heat stress in Aspergillus oryzae colonies.

Hyphae at the outer part of colonies of Aspergillus niger and Aspergillus oryzae are heterogeneous with respect to transcriptional and translational activity. This heterogeneity is maintained by Woronin body mediated closure of septal pores that block interhyphal mixing of cytoplasm. Indeed, heterogeneity between hyphae is abolished in ΔhexA strains that lack Woronin bodies. The subpopulation of hyphae with high transcriptional and translational activity secretes enzymes that degrade the substrate resulting in breakdown products that serve as nutrients. The role of hyphae with low transcriptional and translational activity was not yet known. Here, we show that this subpopulation is more resistant to environmental stress in A. oryzae, in particular to temperature stress, when compared to hyphae with high transcriptional and translational activity. Notably, all hyphae of the ΔhexA strain of A. oryzae were sensitive to heat stress explained by the reduced heterogeneity in this strain. Together, we show that different subpopulations of hypha secrete proteins and resist heat stress showing the complexity of a fungal mycelium.

Novel Approach to Treat Uncomplicated Sigmoid Volvulus Combining Minimally Invasive Surgery with Enhanced Recovery, in a Rural Hospital in Zambia.

AIM: In sub-Saharan Africa, sigmoid volvulus is a frequent cause of bowel obstruction. The aim of this study was to evaluate the results of acute sigmoid resection and anastomosis via a mini-laparotomy in patients with uncomplicated sigmoid volvulus, following the principles of "Enhanced Recovery After Surgery (ERAS)", in a low-resource setting. MATERIALS AND METHODS: Patients with uncomplicated sigmoid volvulus were operated acutely, via a mini-laparotomy, according to the principles of ERAS. Intraoperative complications, duration of operation, morbidity, mortality and length of hospital stay were evaluated, retrospectively. RESULTS: From 1 March 2012 to 1 September 2017, 31 consecutive patients were treated with acute sigmoid resection and anastomosis, via a mini-laparotomy. There were 29 men and 2 women, median age 57 (range 17-92) years. Patients were operated after a median period of 4 (range 1.5-18) hours. The median duration of the operative procedure was 50 (range 30-105) minutes. Two patients died (6.3%). One patient died during an uncomplicated operation. The cause of death is unknown. One patient with a newly diagnosed HIV infection had an anastomotic dehiscence. After Hartmann's procedure, he died on the 17th post-operative day as a result of a HIV-related double-sided pneumonia, without signs of abdominal sepsis. One patient had an urinary retention and 1 patient haematuria after bladder catheter insertion. CONCLUSION: Acute sigmoid resection and primary anastomosis via a mini-laparotomy for uncomplicated sigmoid volvulus, without preoperative endoscopic decompression is a safe procedure with a low morbidity and mortality.

Value of macrobiopsies and transanal endoscopic microsurgery in the histological work-up of rectal neoplasms: A retrospective study.

AIM: To evaluate a step up approach: Taking macrobiopsies and performing excision biopsies in patients with suspected rectal cancer in which biopsies taken though the flexible endoscope showed benign histology. METHODS: Patients with a rectal neoplasm who underwent flexible endoscopy and biopsies were included. In case of benign biopsies rigid rectoscopy and macrobiopsies were employed. If this failed to prove malignancy, transanal endoscopic microsurgery (TEM) was used in a final effort to establish a certain preoperative diagnosis. The preoperative results were compared with the findings after surgical excision and follow up to calculate the reliability of this algorithm. RESULTS: One hundred and thirty-two patients were included. One hundred and ten patients with a carcinoma and 22 with an adenoma. Seventy-five of 110 carcinomas were proven malignant after flexible endoscopy. With the addition of rigid endoscopy and taking of macrobiopsies, this number increased to 89. Performing TEM excision biopsies further enlarged the number of proven malignancies to 100. CONCLUSION: The step-up approach includes taking macrobiopsies through the rigid rectoscope and performing excision biopsies using transanal endoscopic microsurgery in addition to flexible endoscopy. This approach, reduced the number of missed preoperative malignant diagnoses from 32% to 9%.

Prophylactic Mesh Placement During Formation of an End-colostomy Reduces the Rate of Parastomal Hernia: Short-term Results of the Dutch PREVENT-trial.

OBJECTIVE: The aim of this study was to investigate the incidence of parastomal hernias (PSHs) after end-colostomy formation using a polypropylene mesh in a randomized controlled trial versus conventional colostomy formation. BACKGROUND: A PSH is the most frequent complication after stoma formation. Symptoms may range from mild abdominal pain to life-threatening obstruction and strangulation. The treatment of a PSH is notoriously difficult and recurrences up to 20% have been reported despite the use of mesh. This has moved surgical focus toward prevention. METHODS: Augmentation of the abdominal wall with a retro-muscular lightweight polypropylene mesh was compared with the traditional formation of a colostomy. In total, 150 patients (1:1 ratio) were included. The incidence of a PSH, morbidity, mortality, quality of life, and cost-effectiveness was measured after 1 year of follow-up. RESULTS: There was no difference between groups regarding demographics and predisposing factors for PSH. Three out of 67 patients (4.5%) in the mesh group and 16 out of 66 patients (24.2%) in the nonmesh group developed a PSH (P = 0.0011). No statistically significant difference was found in infections, concomitant hernias, SF-36 questionnaire, Von Korff pain score, and cost-effectiveness between both study groups. CONCLUSION: Prophylactic augmentation of the abdominal wall with a retromuscular lightweight polypropylene mesh at the ostomy site significantly reduces the incidence of PSH without a significant difference in morbidity, mortality, quality of life, or cost-effectiveness.

Surgery and Obstetric Care are Highly Cost-Effective Interventions in a Sub-Saharan African District Hospital: A Three-Month Single-Institution Study of Surgical Costs and Outcomes.

BACKGROUND: The Lancet recently sponsored a commission examining the role of surgery in global health. There is a paucity of published information on the cost-effectiveness of surgery in low- and middle-income countries, a key metric in the prioritisation of limited resources. METHODS: All patients undergoing emergency laparotomy, elective and emergency inguinal hernia repair, elective and emergency caesarean section, amputation, fracture manipulation, or fracture fixation over a 3 months period in a single district African hospital were assessed. World Health Organisation global burden of disease (GBD) methodology was used to calculate the disability-adjusted life years (DALYs) saved for each patient (using global and local life expectancy). Fully loaded costs were calculated for each patient's care and providing the overall surgical service. Cost-effectiveness was calculated in year 2012 US$ per DALY saved for each procedure and overall. RESULTS: A total of 428 patients were included, with an overall cost-effectiveness of $10.70 per DALY averted. The cost-effectiveness of individual procedures (global life expectancy) was: Amputation­$17.66; Emergency caesarean section­$7.42; Elective caesarean section­$20.50; Emergency laparotomy­$8.62; Elective hernia repair­$15.26; Emergency hernia repair­$4.36; Fracture/dislocation reduction­$69.03; Fracture/dislocation fixation­$225.89. CONCLUSIONS: Surgery is a highly cost-effective healthcare measure in the setting of an African district hospital. The presented outcomes demonstrate that surgery is on a par with better-recognised and funded interventions such as HIV anti-retrovirals, malaria prevention and diarrhoea treatment. There are recognised limitations with the GBD methodology used here; however, this remains the best way to investigate the cost-effectiveness of health interventions. This study provides useful information on an, at present, under-studied field.

A Markov Decision Model to Guide Treatment of Recurrent Colonic Diverticulitis.

BACKGROUND & AIMS: Although colonic diverticulitis is a common disorder, there is no clear treatment strategy for patients with recurrent episodes of diverticulitis. We investigated whether colonic resection or conservative or medical treatments have the greatest effects on quality-adjusted life-years (QALYs). METHODS: A Markov model simulating patients with 2 episodes of non-surgically treated diverticulitis was used to simulate all relevant outcomes of each treatment strategy. A 1-year cycle length with 10-year follow-up period was used to allow for chance of recurrent diverticulitis. Primary outcome was QALYs gained from each strategy. Factors considered were morbidity, mortality, chance of colostomy formation, risk of recurrence, and persistence of abdominal pain. The probabilities of clinical events were determined by using the best available published data. RESULTS: A strategy in which colonic resection was performed after 2 episodes of diverticulitis was associated with the lowest quality-adjusted survival (a gain of 8.66 QALYs) and highest chance of stoma formation (1.1%) but the lowest chance of a mild (3.5%) or severe (1.1%) recurrence. The strategies of colonic resection or conservative or medical treatment after the third episode of diverticulitis were comparable in terms of quality-adjusted survival, providing 8.78, 8.76, and 8.74 QALYs, respectively. Probabilistic sensitivity analysis did not change these results. Persistent abdominal complaints were lowest in the medical treatment strategy. CONCLUSIONS: Elective surgery after 2 episodes of diverticulitis should be questioned in terms of QALYs. After the third episode of diverticulitis, surgical or conservative or medical treatments provide similar QALYs, but rates of abdominal symptoms are lower with the medical treatment strategy. This Markov decision model has limitations when the individual patient and physician face a complex decision weighing early and long-term risks and benefits of elective surgery or conservative management.

Large Contaminated Ventral Hernia Repair Using Component Separation Technique with Synthetic Mesh.

BACKGROUND: Large ventral hernia repair represents a major reconstructive surgical challenge, especially under contaminated conditions. Synthetic mesh is usually avoided in these circumstances because of fear of mesh infection, although evidence is outdated and does not regard new materials and techniques. The authors evaluated the safety of synthetic mesh in large contaminated ventral hernia repair. METHODS: All large ventral hernias repaired with the components separation technique and polypropylene mesh were included in analysis. Primary outcomes were wound and medical complications, with a focus on surgical-site infection and mesh removal. For risk analysis, patients were stratified by surgical wound class, Ventral Hernia Working Group grade, and modified Ventral Hernia Working Group grade. RESULTS: One hundred thirty-seven patients were included, with a mean age of 58.6 years, mean body mass index of 26.6 cm2, and mean defect size of 235.6 cm2. Surgical-site infection and total wound complication rates were 16.1 and 48.9 percent, respectively. The surgical wound class distribution of surgical-site infections was as follows: clean, five of 56 (9.1 percent); clean-contaminated, five of 34 (14.7 percent); contaminated, three of 19 (15.8 percent); and dirty/infected, nine of 28 (32.1 percent). Seven meshes (5.1 percent) needed removal, two after clean repairs, three after clean-contaminated repairs, and two after dirty/infected repairs. Surgical wound class (OR, 1.77; 95 percent CI, 1.20 to 2.61) and Ventral Hernia Working Group grade (OR, 2.31; 95 percent CI, 1.24 to 4.28) were predictors of surgical-site infection. CONCLUSION: Rate of surgical-site infection after large contaminated ventral hernia repair with synthetic mesh is considerable but with a low mesh removal rate.

Selective transport between heterogeneous hyphal compartments via the plasma membrane lining septal walls of Aspergillus niger.

Hyphae of ascomycetes are compartmentalized by septa. The central pore in these septa allows for cytoplasmic streaming. However, many of these pores are closed by Woronin bodies in Aspergillus, which prevents cytoplasmic mixing and thus maintains hyphal heterogeneity. Here, glucose uptake and transport was studied in Aspergillus niger. Glucose uptake was higher in the hyphal population with high transcriptional activity when compared to the population with low transcriptional activity. Glucose was transported from the colony center to the periphery, but not vice versa. This unidirectional flow was similar in the wild-type and the ΔhexA strain that does not form Woronin bodies. This indicated that septal plugging by Woronin bodies does not impact long distance glucose transport. Indeed, the glucose analogue 2-NBDG (2-(N-[7-nitrobenz-2-oxa-1,3-diazol-4-yl]amino)-2-deoxyglucose) translocated to neighboring hyphal compartments despite Woronin body mediated plugging of the septum that separated these compartments. Notably, 2-NBDG accumulated in septal cross walls, indicating that intercompartmental glucose transport is mediated by transporters that reside in the plasma membrane lining the septal cross-wall. The presence of such transporters would thus enable selective transport between heterogeneous compartments.

Switching from a unicellular to multicellular organization in an Aspergillus niger hypha.

UNLABELLED: Pores in fungal septa enable cytoplasmic streaming between hyphae and their compartments. Consequently, the mycelium can be considered unicellular. However, we show here that Woronin bodies close ~50% of the three most apical septa of growing hyphae of Aspergillus niger. The incidence of closure of the 9th and 10th septa was even ≥94%. Intercompartmental streaming of photoactivatable green fluorescent protein (PA-GFP) was not observed when the septa were closed, but open septa acted as a barrier, reducing the mobility rate of PA-GFP ~500 times. This mobility rate decreased with increasing septal age and under stress conditions, likely reflecting a regulatory mechanism affecting septal pore diameter. Modeling revealed that such regulation offers effective control of compound concentration between compartments. Modeling also showed that the incidence of septal closure in A. niger had an even stronger impact on cytoplasmic continuity. Cytoplasm of hyphal compartments was shown not to be in physical contact when separated by more than 4 septa. Together, data show that apical compartments of growing hyphae behave unicellularly, while older compartments have a multicellular organization. IMPORTANCE: The hyphae of higher fungi are compartmentalized by porous septa that enable cytosolic streaming. Therefore, it is believed that the mycelium shares cytoplasm. However, it is shown here that the septa of Aspergillus niger are always closed in the oldest part of the hyphae, and therefore, these compartments are physically isolated from each other. In contrast, only part of the septa is closed in the youngest part of the hyphae. Still, compartments in this hyphal part are physically isolated when separated by more than 4 septa. Even open septa act as a barrier for cytoplasmic mixing. The mobility rate through such septa reduces with increasing septal age and under stress conditions. Modeling shows that the septal pore width is set such that its regulation offers maximal control of compound concentration levels within the compartments. Together, we show for the first time that Aspergillus hyphae switch from a unicellular to multicellular organization.

VeA of Aspergillus niger increases spore dispersing capacity by impacting conidiophore architecture.

Aspergillus species are highly abundant fungi worldwide. Their conidia are among the most dominant fungal spores in the air. Conidia are formed in chains on the vesicle of the asexual reproductive structure called the conidiophore. Here, it is shown that the velvet protein VeA of Aspergillus niger maximizes the diameter of the vesicle and the spore chain length. The length and width of the conidiophore stalk and vesicle were reduced nearly twofold in a ΔveA strain. The latter implies a fourfold reduced surface area to develop chains of spores. Over and above this, the conidial chain length was approximately fivefold reduced. The calculated 20-fold reduction in formation of conidia by ΔveA fits the 8- to 17-fold decrease in counted spore numbers. Notably, morphology of the ΔveA conidiophores of A. niger was very similar to that of wild-type Aspergillus sydowii. This suggests that VeA is key in conidiophore architecture diversity in the fungal kingdom. The finding that biomass formation of the A. niger ΔveA strain was reduced twofold shows that VeA not only impacts dispersion capacity but also colonization capacity of A. niger.

Safety and durability of one-stage repair of abdominal wall defects with enteric fistulas.

OBJECTIVE: To evaluate the safety and long-term durability of 1-stage repair of enteric fistulas in the presence of an abdominal wall defect. BACKGROUND: Patients with enteric fistulas and an abdominal wall defect present an extreme challenge to surgeons and have been associated with significant morbidity and mortality. Durability of repair is unknown as studies fail to report this or use limited follow-up periods. METHODS: Chart review was done of consecutive patients who underwent 1-stage repair. Short-term outcomes included morbidity (wound and medical) and mortality. Long-term durability of repair was determined by prospective outpatient follow-up at least 3 years after surgery. RESULTS: Thirty-nine patients were included with a mean age of 61.2 years, a mean BMI of 24.4 kg/m2, and a mean abdominal wall defect size of 247.9 cm2. Component separation technique was used in 34 (87.2%) and synthetic mesh in 13 (33.3%) patients. There was 1 (2.6%) postoperative death. Twenty-four wound complications developed in 18 (46.2%) patients, including surgical-site infection in 8 (20.5%) patients. Two (5.1%) enteric fistulas recurred and were treated conservatively resulting in closure. Medical complications were seen 36 times in 23 (59%) patients. Twelve of 33 (36.4%) living patients developed a recurrent hernia after a mean follow-up of 62.7 months (range: 36-130). CONCLUSIONS: One-stage abdominal wall reconstruction with enteric fistula takedown is feasible at the cost of considerable morbidity. Our treatment strategy including component separation technique with synthetic mesh on-demand results in a durable repair in 6 to 7 of 10 patients.

Large and complex ventral hernia repair using "components separation technique" without mesh results in a high recurrence rate.

BACKGROUND: Recurrence rates after component separation technique (CST) are low in the literature but may be underestimated because of inadequate follow-up methods. METHODS: Prospective patient follow-up was performed of consecutive patients who underwent repair of large and complex ventral hernias using CST without mesh utilization. Primary outcome was recurrent hernia determined by clinical examination at least 1 year after surgery in all living patients. Current literature underwent meta-analysis regarding outcomes and mode of follow-up. RESULTS: Seventy-five patients were included with a mean age of 52.2 years and a mean defect size of 214.9 cm(2), respectively. Twenty-nine patients (38.7%) had a recurrent hernia after a mean of 40.9-month follow-up, and this was significantly higher than in the literature (14.0%, P < .01). Sixty-four percent of studies in the literature were unclear about the method of determining recurrent hernia or included telephone follow-up and questionnaires. CONCLUSIONS: CST coincides with a high recurrence rate when clinical follow-up is longer than a year. Reported recurrence rates are probably underestimated because the method and duration of follow-up are inadequate.

Toward an evidence-based step-up approach in diagnosing diverticulitis.

BACKGROUND: The lack of pathognomonic findings and the chance of complicated disease have resulted in the widespread use of additional imaging to diagnose acute colonic diverticulitis (ACD). The added value of additional imaging in the diagnostic workup of patients suspected of ACD is not well defined. AIMS: The aim of this study was to systematically review the literature of the accuracy of the clinical evaluation and diagnostic modalities for patients with suspected ACD, to come to an evidence-based approach to diagnose ACD. METHODS: A systematic review and meta-analysis of studies that reported diagnostic accuracy of the clinical diagnosis and diagnostic modalities in patients with suspected diverticulitis were performed. Study quality was assessed with the STARD checklist. True-positive, true-negative, false-positive, and false-negative findings were extracted and pooled estimates of sensitivity and specificity per diagnostic test were calculated, if applicable. RESULTS: The overall quality of the studies reporting the diagnostic accuracy of the clinical diagnosis, contrast enema and magnetic resonance imaging (MRI) were moderate to poor and not suitable for meta-analysis. Sensitivity of the clinical diagnosis varied between 64% and 68%. Ultrasound (US) and computed tomography (CT) studies were eligible for meta-analysis. Summary sensitivity estimates for US were 90% (95% CI: 76-98%) versus 95% (95% CI: 91-97%) for CT (p = 0.86). Summary specificity estimates for US were 90% (95% CI: 86-94%) versus 96% (95% CI: 90-100%) for CT (p = 0.04). Sensitivity for MRI was 98% and specificity varied between 70% and 78%. Sensitivity of contrast enema studies varied between 80% and 83%. CONCLUSION: In two-thirds of the patients, the diagnosis of ACD can be made based on clinical evaluation alone. In one-third of the patients, additional imaging is a necessity to establish the diagnosis. US and CT are comparable in diagnosing diverticulitis and superior to other modalities. CT has the advantage of higher specificity and the ability to identify alternative diagnoses. The role of MRI is not yet clear in diagnosing ACD. Contrast enema is considered an obsolete imaging technique to diagnose ACD based on lower sensitivity and specificity than US and CT. A step-up approach with CT performed after an inconclusive or negative US, seems a logical and safe approach for patients suspected of ACD.