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Background/Purpose: The water jet technique dissects tissue while sparing cord-like structures such as blood vessels. The mechanism of such tissue-selective dissection has been unknown. The novel piezo actuator-driven pulsed water jet (ADPJ) system can achieve dissection with remarkably reduced water consumption compared to the conventional water jet; however, the system's characteristics and dissection capabilities on any organ have not been clarified. The purposes of this study were to characterize the physical properties of the novel ADPJ system, evaluate the dissection ability in swine organs, and reveal the mechanism of tissue-selective dissection. Methods: The pulsed water jet system comprised a pump chamber driven by a piezo actuator, a stainless steel tube, and a nozzle. The peak pressure of the pulsed water jet was measured through a sensing hole using a pressure sensor. The pulsed water jet technique was applied on swine liver in order to dissect tissue on a moving table using one-way linear ejection at a constant speed. The dissection depth was measured with light microscopy and evaluated histologically. The physical properties of swine liver were evaluated by breaking strength tests using tabletop universal testing instruments. The liver parenchyma was also cut with three currently available surgical devices to compare the histological findings. Results: The peak pressure of the pulsed water jet positively correlated with the input voltage (R2 = 0.9982, p < 0.0001), and this was reflected in the dissection depth. The dissection depth negatively correlated with the breaking strength of the liver parenchyma (R2 = 0.6694, p < 0.0001). The average breaking strengths of the liver parenchyma, hepatic veins, and Glisson's sheaths were 1.41 ± 0.45, 8.66 ± 1.70, and 29.6 ± 11.0 MPa, respectively. The breaking strength of the liver parenchyma was significantly lower than that of the hepatic veins and Glisson's sheaths. Histological staining confirmed that the liver parenchyma was selectively dissected, preserving the hepatic veins and Glisson's sheaths in contrast to what is commonly observed with electrocautery or ultrasonic instruments. Conclusions: The dissection depth of liver tissue is well controlled by input voltage and is influenced by the moving velocity and the physical properties of the organ. We showed that the device can be used to assure liver resection with tissue selectivity due to tissue-specific physical properties. Although this study uses an excised organ, further in vivo studies are necessary. The present work demonstrates that this device may function as an alternative tool for surgery due to its good controllability of the dissection depth and ability of tissue selectivity. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Retrospective studies have drawn attention to possible detrimental effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the anastomotic leakage rate after colorectal resection. In this study, we examined the effects of the NSAID diclofenac on the breaking strength of an experimental colonic anastomosis and a skin incision as well as subcutaneous collagen accumulation. Methods: This was a randomized, blinded, placebo-controlled experimental study in 60 male Wistar rats treated with diclofenac 4 mg/kg/day or placebo. In each rat, a colonic anastomosis was performed and an expanded polytetrafluoroethylene (ePTFE) tube was placed subcutaneously. Incisional and anastomotic wound breaking strength and hydroxyproline content in the ePTFE tubes were measured 7 days after the operation. Results: We found no significant differences in any of the breaking strength measurements, but showed a median 38% reduction in hydroxyproline deposition as a result of diclofenac treatment (p = 0.03). In the placebo group, subcutaneous collagen deposition tended to correlate positively with skin incisional but negatively with anastomotic bio-mechanical strength. Conclusion: Postoperative diclofenac treatment significantly inhibited collagen deposition in subcutaneous granulation tissue. Anastomotic strength and skin wound strength were not significantly affected. The ePTFE model is suitable for assessing the effect of various drugs on collagen formation and thus on wound healing. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Recently, there has been a focus on the effect of the nonsteroidal anti-inflammatory drugs on the anastomotic leakage rate after colorectal surgery. Methods: An experimental, randomized, placebo-controlled prospective study on 32 male Wistar rats was carried out. We examined the effect of diclofenac 4 mg/kg/day on the cyclooxygenase-2 (COX-2) enzyme in the anastomotic tissue and on the breaking strength of anastomotic and incisional wounds. The operation was performed with colonic resection and hand-sewn anastomosis. After 3 days, the rats were sacrificed and the breaking strength and the COX-2 content of the anastomosis were measured. Results: There was a significantly reduced level of COX-2 in the rats treated with diclofenac (p = 0.001); no significant differences in any of the breaking strength measurements and no significant correlation between COX-2 levels and breaking strength of the anastomotic or incisional wounds could be found (p = 0.073 and p = 0.727). Conclusion: This study for the first time showed that a diclofenac dose of 4 mg/kg/24 h was sufficient to reduce the level of COX-2 enzymes in the anastomotic tissue in rats. This inhibition of the inflammatory response did not lead to reduced breaking strength of either anastomotic or incisional wounds. Whether there is a detrimental effect of COX inhibition on colorectal anastomoses in the clinical setting remains controversial. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: The properties of proton pump inhibitors most investigated are related to peptic diseases and upper gastrointestinal bleeding, but their influence on the healing of sutured gastric incisions has not been assessed. In the present study we evaluated the effect of subcutaneously administered pantoprazole on the healing of sutured gastric incisions in rats. Methods: Sixty rats were divided into a pantoprazole group and a control group. All rats were submitted to gastric suture in the gastric body and in the gastric fundus and had their gastric pH measured. The pantoprazole group received 20 mg/kg pantoprazole and the control group received 0.9% isotonic NaCl, both subcutaneously t.i.d. Healing analysis was carried out using collagen picrosirius red F3BA staining, and breaking strength was measured on the 4th and 7th postoperative days in all groups. Results: Gastric pH was higher in the pantoprazole group. In the fundus, the pantoprazole group had a higher measurement of breaking strength and a higher proportion of type-I over type-III collagen on the 7th postoperative day. In the body, the pantoprazole group had a higher proportion of type-I over type-III collagen on the 4th and 7th postoperative days. Conclusions: Pantoprazole given subcutaneously promoted a reduction in gastric acid secretion and was associated with improved healing of the sutured gastric incision in the fundus (squamous epithelium) of rats. These findings suggest that pantoprazole has healing properties in sutured gastric incisions with potential benefits in gastric surgery. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

In the present study, we examined the effect of a diverting colostomy on the intestinal healing of colonic anastomosis in the rat. For this purpose, we created a colonic stenosis 2 days prior to the formation of a distal one-layer end-to-end anastomosis with or without a proximal double-barreled deviation colostomy in the rats. Radiological examination of anastomotic leakage was performed daily for 4 days and on day 7 after the operation. We found that anastomotic leakage was markedly increased in rats with a diverting colostomy compared to control animals; i.e. the leakage index (percentage of days with leakage during the experimental period) in colostomy rats was 29%, whereas in animals with no colostomy, the leakage index was only 7%. Interestingly, it was observed that anastomosis formation was associated with a higher mortality rate in rats with colostomy diversion (36%) compared to control animals (7%). However, there was no difference in suture holding capacity on day 7. Moreover, body weight decreased significantly in the colostomy group compared to rats without surgical defunctioning when followed for up to 7 days after surgery. Taken together, our novel findings suggest that a diverting colostomy may increase intestinal leakage after anastomosis formation in the rat colon. Thus, the role of proximal colostomy in the protection of colorectal anastomosis needs to be reevaluated and further investigations are required to resolve the influence of surgical defunctioning on intestinal healing.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]