Endoluminal Vacuum Therapy (E-Vac): A Treatment Option in Oesophagogastric Surgery.

BACKGROUND: Leaks from the upper gastrointestinal tract often pose a management challenge, particularly when surgical treatment has failed or is impossible. Vacuum therapy has revolutionised the treatment of wounds, and its role in enabling and accelerating healing is now explored in oesophagogastric surgery. METHODS: A piece of open cell foam is sutured around the distal end of a nasogastric tube using a silk suture. Under general anaesthetic, the foam covered tip is placed endoscopically through the perforation and into any extra-luminal cavity. Continuous negative pressure (125 mmHg) is then applied. Re-evaluation with change of the negative pressure system is performed every 48-72 h depending on the clinical condition. Patients are fed enterally and treated with broad-spectrum antibiotics and anti-fungal medication until healing, assessed endoscopically and/or radiologically, is complete. RESULTS: Since April 2011, twenty one patients have been treated. The cause of the leak was postoperative/iatrogenic complications (14 patients) and ischaemic/spontaneous perforation (seven patients). Twenty patients (95%) completed treatment successfully with healing of the defect and/or resolution of the cavity and were subsequently discharged from our care. One patient died from sepsis related to an oesophageal leak after withdrawing consent for further intervention following a single endoluminal vacuum (E-Vac) treatment. In addition, two patients who were successfully treated with E-Vac for their leak subsequently died within 90 days of E-Vac treatment from complications that were not associated with the E-Vac procedure. In two patients, E-Vac treatment was complicated by bleeding. The median number of E-Vac changes was 7 (range 3-12), and the median length of hospital stay was 35 days (range 23-152). CONCLUSIONS: E-Vac therapy is a safe and effective treatment for upper gastrointestinal leaks and should be considered alongside more established therapies. Further research is now needed to understand the mechanism of action and to improve the ease with which E-Vac therapy can be delivered.

Confocal laser scanning microscopy and area-scale analysis used to quantify enamel surface textural changes from citric acid demineralization and salivary remineralization in vitro.

OBJECTIVES: This paper investigates the application of confocal laser scanning microscopy to determine the effect of acid-mediated erosive enamel wear on the micro-texture of polished human enamel in vitro. METHODS: Twenty polished enamel samples were prepared and subjected to a citric acid erosion and pooled human saliva remineralization model. Enamel surface microhardness was measured using a Knoop hardness tester, which confirmed that an early enamel erosion lesion was formed which was then subsequently completely remineralized. A confocal laser scanning microscope was used to capture high-resolution images of the enamel surfaces undergoing demineralization and remineralization. Area-scale analysis was used to identify the optimal feature size following which the surface texture was determined using the 3D (areal) texture parameter Sa. RESULTS: The Sa successfully characterized the enamel erosion and remineralization for the polished enamel samples (P<0.001). SIGNIFICANCE: Areal surface texture characterization of the surface events occurring during enamel demineralization and remineralization requires optical imaging instrumentation with lateral resolution <2.5 µm, applied in combination with appropriate filtering in order to remove unwanted waviness and roughness. These techniques will facilitate the development of novel methods for measuring early enamel erosion lesions in natural enamel surfaces in vivo.

Matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1 and tumour necrosis factor alpha release during cardiopulmonary bypass.

An inflammatory response occurs during cardiac surgery involving cardiopulmonary bypass. Matrix metalloproteinase-9 is an enzyme involved in cytokine processing and leucocyte extravasation. It is secreted as a pro-enzyme in response to several inflammatory mediators and is inhibited by endogenous tissue inhibitor of metalloproteinase-1. The interaction between matrix metalloproteinase-9 and its inhibitor during cardiopulmonary bypass is not known. We measured tumour necrosis factor alpha, and matrix metalloproteinase-9 and its inhibitor using enzyme immunoassay at three time points in 20 patients undergoing elective coronary artery bypass grafting with cardiopulmonary bypass. Tumour necrosis factor and matrix metalloproteinase concentrations increased in all patients during bypass (both p < 0.0001), whereas the inhibitor in contrast, decreased (p < 0.0001). We conclude that matrix metalloproteinase-9 is released as part of the inflammatory response during cardiac surgery. Levels of the endogenous inhibitor of metalloproteinase, however, show a different pattern of release, suggesting independent regulation.