• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.7
• /
• pp.921-929
• /
• 2011

We measured experimentally the properties of fluid dynamics, velocity fields, and the pressure, around stenotic obstruction located inside a circular channel structure. Particle image velocimetry system was employed to obtain velocity fields at the central section of the circular channel in the streamwise direction. The stenosis model used was made of acrylic material with different stenotic aspect ratios. The working fluid was water and it was returned by a centrifugal pump system. Pressure measurements were carried out to validate the effect of a narrow passageway. Results showed that the acceleration of gap flow through stenotic obstruction and the pressure drop in the recirculation regime behind the stenosis model can be observed.

• Advances in pediatric surgery
• /
• v.10 no.2
• /
• pp.123-126
• /
• 2004

Intestinal obstruction secondary to intraabdominal adhesion is a well-known postoperative complication occurring after appendectomy. The aim of this study was to measure the incidence and clinical manifestations of mechanical intestinal obstruction after appendectomy for perforated appendicitis. We reviewed all of the children (age <16 years) who had been treated for appendicitis at Asan Medical Center between January 1996 and December 2001. Inclusion criterion included either gross or microscopic evidence of appendiceal perforation. Exclusion criteria were interval appendectomy, and patients immune compromised by chemotherapy. Associations of intestinal obstruction with age, sex, operation time, and use of peritoneal drains were analyzed. Four hundred and sixty two open appendectomies for appendicitis were performed at our department. One hundred and seventeen children were treated for perforated appendicitis (78 boys, 39 girls). The mean age was 8.9 years (range 1.5 to 14.8 years). There were no deaths. Eight patients were readmitted due to intestinal obstruction, but there was no readmission due to intestinal obstruction in patients with non-perforated appendicitis. The interval between appendectomy and intestinal obstruction varied from 12 days to 2 year 7 months. Four patients needed laparotomies. In three of four, only adhesiolysis was performed. One child needed small bowel resection combined with adhesiolysis. There was no significant association between age or sex and the development of intestinal obstruction. This was no association with operative time or use of peritoneal drain. Patients who required appendectomy for perforated appendicitis have a higher incidence of postoperative intestinal obstruction than those with nonperforated appendicitis. For the patients with perforated appendicitis, careful operative procedures as well as pre and postoperative managements are required to reduce adhesions and subsequent bowel obstruction.

• Journal of Korean Neurosurgical Society
• /
• v.46 no.3
• /
• pp.226-231
• /
• 2009

Objective : We describe our clinical experiences and outcomes in patients who had thromboembolic complications occurring during endovascular treatment of intracerebral aneurysms with a review of the literature. The types of thromboembolic complications were divided and the treatment modalities for each type were described. Methods : Between August 2004 and March 2009 we performed endovascular embolization with Guglielmi detachable coils for 173 patients with 189 cerebral aneurysms, including ruptured and unruptured aneurysms at our hospital. Sixty-eight patients were males and 105 patients were females. The age of patients ranged from 22-82 years (average, 58.8 years). We retrospectively evaluated this group with regard to complication rates and outcomes. The types of thromboembolic complications were classified into the following three categories: mechanical obstruction, distal embolic stroke, and stent-induced complications, which corresponded to types I, II, and III, respectively. A comparison of the clinical results was made for each type of complication. Results : Only eight patients had a thromboembolic complication during or after a procedure (4.6%). Of the eight patients, two had a mechanical obstruction as the causative factor; the other three patients had distal embolic stroke as the causative factor. The remaining three patients had stent-induced complications. In cases of mechanical obstruction, recanalization occurred due to the use of intra-arterial thrombolytic agents in one of two patients. Nevertheless, a poor prognosis was seen. In the cases of stent-induced complications, in one of three patients in whom a thrombus developed following stent insertion, a middle cerebral artery territory infarct developed with a poor prognosis despite the use of wiring and an intra-arterial thrombolytic agent. In the cases of distal embolic stroke, all three patients achieved good results following the use of antiplatelet agents. Conclusion : Treatment for thromboemboic complications due to mechanical obstruction and stent-induced complications include antiplatelet and intra-arterial thrombolytic agents; however, this cannot guarantee a sufficient extent of effectiveness. Therefore, active treatments, such as balloon angioplasty, stent insertion, and clot extraction, are helpful.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.22 no.3
• /
• pp.291-297
• /
• 2019

Bowel ischemia is a life-threatening surgical emergency. We report a case of rapidly progressive bowel necrosis in a previously healthy child without proven mechanical small bowel obstruction. The definite diagnosis was established at the time of an exploratory operation. Of note, imaging studies and even a laparotomy did not reveal any evidence of acute appendicitis or mechanical obstruction such as intussusception or Meckel's diverticulum. During hospitalization, since we could not rule out surgical abdomen after inconclusive image findings, we closely followed the patient and repeated physical examinations carefully. Eventually surgical exploration was performed based on changes in clinical condition, which proved to be the right decision for the patient. We propose that in children with suspected strangulation of small bowel obstruction, especially when imaging findings do not provide a conclusive diagnosis, the timely exploratory surgical approach ought to be chosen based on carefully observed clinical findings and other evaluations.

• Journal of Mechanical Science and Technology
• /
• v.17 no.6
• /
• pp.879-887
• /
• 2003

The flow in a parallel walled test channel, when obstructed with a geometry at the entrance, can be forward, reverse and stagnant depending on the position of the obstruction. This interesting flow phenomenon has potential benefit in the control of energy and various flows in the process industry In this experiment, the flat plate obstruction geometry was used as an obstruction at the entry of the test channel. The parameters that influence the flow inside and around the test channel were the gap (g) between the test channel and the obstruction geometry, the length (L) of the test channel and the Reynolds number (Re). The effect of the gap to channel width ratio (g/w) on the magnitude of the velocity ratio (V$\_$i/ / V$\_$o/ : velocity inside/ velocity outside the test channel) was investigated for a range of Reynolds numbers. The maximum reverse flow observed was nearly 20% to 60% of the outside velocity for Reynolds number ranging from 1000 to 9000 at g/w ratio of 1.5. The maximum forward velocity inside the test channel was found 80% of the outside velocity at higher g/w ratio of 8. The effect of the test channel length on the velocity ratio was investigated for different g/w ratios and a fixed Reynolds number of 4000. The influence of the Reynolds number on the velocity ratio is also discussed and presented for different gap to width ratio (g/w). The flow visualisation photographs showing fluid motion inside and around the test channel are also presented and discussed.

• Journal of Veterinary Clinics
• /
• v.41 no.2
• /
• pp.127-132
• /
• 2024

A 6-month-old intact female Bichon Frise dog weighing 0.9 kg presented with vomiting, anorexia, and lethargy persisting for 3 days. No remarkable abnormalities were detected on the history or physical examination. Laboratory findings were mostly normal, except for elevated levels of alkaline phosphatase (ALP) and blood urea nitrogen (BUN). Abdominal radiography revealed a fluid-dilated stomach and gas-dilated intestinal loops in the regional areas. Abdominal ultrasonography was performed to investigate the cause of gastrointestinal dilation, which revealed a rectangular, homogeneous, echogenic foreign material with no shadowing in the small intestine, causing mechanical obstruction. Upon further inquiry involving detailed re-take of history with the owner, a history of ingesting dog gum 4 days prior was identified. On surgical enterotomy, the hard pet food was identified and removed from the distal duodenum. Postoperatively, the patient's clinical signs showed complete improvement, with a return to normal appetite. The present case demonstrates that less-digestible, hard pet food, despite showing no shadowing on ultrasonography, can act as a foreign material, causing mechanical intestinal obstruction in a small-breed puppy. Furthermore, surgical removal of these materials is necessary in cases of intestinal obstruction.

• Journal of Digestive Cancer Research
• /
• v.10 no.2
• /
• pp.92-98
• /
• 2022

Self-expandable metal stent (SEMS) is effective for biliary drainage, especially in pancreaticobiliary cancer. The mechanical properties, material, and design of SEMS are important in preventing recurrent biliary obstruction and complication. Radial and chronic expansion forces play roles in preventing stent migration and collapse. Complications, such as stent impaction, cholecystitis, and pancreatitis, were related to the axial force. The nickel-titanium alloy shows more flexibility, conformability, and optimal axial force compared to previously used stainless steel. Additionally, the stent structure affected the mechanical properties of SEMS. Therefore, understanding the mechanical properties, material, and design of SEMS will provide the best outcome for biliary drainage, as well as better SEMS development.

• Journal of Veterinary Clinics
• /
• v.33 no.3
• /
• pp.179-182
• /
• 2016

An 11-year-old castrated male Maltese had vomiting, diarrhea, and abdominal distension for over two weeks and weight loss for several months. Clinical laboratory studies were not remarkable. Abdominal radiographs showed severe dilated intestine with a gravel sign. Colon was empty with normal diameter in the pneumocolon study. On ultrasonographs, most small bowel loops were dilated without normal peristalsis and showed abnormal thin wall. Barium contrast study revealed remarkably delayed gastric emptying and transit time up to $6^{th}$ day. On exploratory laparotomy, there were no mechanical obstruction and extra-intestinal abnormalities except severe dilated small intestine. Chronic fibrosing lymphohistiocytic leiomyositis with atrophy of tunica muscularis in the small intestines and colon was identified through full thickness biopsy and histopathology. Therefore, primary myopathic chronic intestinal pseudo-obstruction was diagnosed. This dog is survival with symptomatic treatments for eight months.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.18 no.4
• /
• pp.280-285
• /
• 2015

Heterotopic pancreas (HP) is defined as pancreatic tissue lacking anatomic and vascular continuity with the main body of the pancreas. Most are asymptomatic, but can cause ulcer, bleeding, intussusception, and mechanical obstruction. Herein, we presented one case of HP presented as duodenal tumor causing duodenal obstruction. A 7-year-old girl visited the emergency room for abdominal pain with vomiting for 24 hours. Computed tomography and upper gastrointestinal series revealed a polypoid mass with short stalk in the 2nd portion of duodenum. We attempted an endoscopic removal. However, the lumen was nearly obstructed by the mass and the stalk was too broad and hard to excise. The mass was surgically removed via duodenotomy. It was confirmed as a HP with ductal and acini components (type 2 by Heinrich classification). Postoperatively, the patient has been well without any complication and recurrence.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.18 no.3
• /
• pp.193-196
• /
• 2015

A fecaloma refers to a mass of accumulated feces that is much harder than a mass associated with fecal impaction. Fecalomas are usually found in the rectosigmoid area. A 10-year-old male with chronic constipation was admitted because of increasing abdominal pain. An abdominal computed tomography scan and a simple abdominal x-ray revealed rapidly evolving mechanical obstruction in the small intestine. Most of the fecalomas are successfully treated by conservative methods such as laxatives, enemas and rectal evacuation. When conservative treatments have failed, surgical intervention may be needed. In this case, an emergency operation was performed and a $4{\times}3{\times}2.5cm$ fecaloma was found in the distal ileum. We thus report a case of ileal fecaloma inducing small bowel obstruction in a patient with chronic constipation, who required surgical intervention. When symptoms of acute small intestinal obstruction develop in a patient with chronic constipation, a fecaloma should be considered in differential diagnosis.