The use of self-expanding metallic stents in the upper gastrointestinal tract, placed under radiologic imaging or endoscopic guidance, is the current treatment of choice for the palliation of malignant gastrointestinal outlet obstructions. Advances in metallic stent design and delivery systems have progressed to the stage where this treatment is now considered a minimally invasive therapy. Metallic stent placement will broaden further into the field of nonsurgical therapy for the gastrointestinal tract. To date, metallic stents placed in the esophagus, gastric outlet, colorectum, and bile ducts are not intended to be curative, but rather to provide a palliative treatment for obstructions. The evolution of metallic stent technology will render such procedures not only palliative but also therapeutic, by enabling local drug delivery, and the use of biodegradable materials will reduce procedure-related complications.
Bile Ducts ; Esophagus ; Gastrointestinal Tract ; Palliative Care ; Stents ; Upper Gastrointestinal Tract

Sodium nitrorusside (SNP) is used for induced hypotension to decrease bleeding in operation site by direct relaxation of vascular smooth muscles. It is known that the infusion of SNP increases plasma renin activity (PRA) and this activation of renin-angiotensin system is one of physiologic mechanism opposing the hypotensive action. Captopril, the renin-angiotensin converting enzyme inhibitor, could reduced the dose of SNP during induced hypotension through blocking of the cardiovascular effect of renin-angiotensin system. The present study investigates the effect of captopril on PRA, aldosterone, elecholamines and electroytes and whether the pretreatment with captoril can reduce the dose of SNP. Forty patients who needed the induced hypotension for maxillofacial reconstructive surgery were studied. They were pertained to ASA class I and II and classified to 4 groups. Ten patients were pretreated with captopril 3 mg/kg, 10 min. before induction. And ten patients were 1 mg/kg, the other ten patients were 0.5 mg/kg and remainder served as control group. Blood samples for analysis were drawn according to the time sequence of SNP infusion; Stage 1; after the induction and before SNP infusion Stage 2; 30 min. after SNP (when mean arterial pressure was 60-70 torr) infusion Stage 3; before stopping infusion of SNP Stage 4; 30 min. after stopping infusion of SNP The results were as follows: 1) The duration of anesthesia were not stastically different among four groups. 2) Total dose of SNP were significantly decreased in each captopril group. 3) PRA and each value of control group were significantly increased compared with stage l. But there were no significant increase in stages 2, 3, 4 compared with control group PRA. 4) Aldosterone level of all captopril groups were decreased in all stage compared with control group. 5) Epinephrine and norepinephrine were significantly incerased in control group and returned to control level after stopping of SNP infusuon. In captopril group 3 mg/kg, norepinephrine of stage 2.3.4 were not significantly increased than stage l. Epinephrine in captopril 3 mg/ kg group, there were no significant changes except for stage 2. 6) While sodium was decreased in stage 3,4 compared with stage 1 in control group, potassium and chloride were not changed. In summary, captopril can reduce significantly the total dose of SNP required to produce induced hypotension during operation.
Aldosterone* ; Anesthesia ; Arterial Pressure ; Captopril* ; Catecholamines* ; Electrolytes* ; Epinephrine ; Hemorrhage ; Humans ; Hypotension* ; Muscle, Smooth, Vascular ; Nitroprusside* ; Norepinephrine ; Plasma* ; Potassium ; Relaxation ; Renin* ; Renin-Angiotensin System ; Sodium*

PURPOSE: We studied to determine whether the degenerative spondylolisthesis has rotary deformity in addition to forward displacement. MATERIALS AND METHODS: We have made an analysis of difference of rotary deformity between the 31 study groups of symptomatic degenerative spondylolisthesis and 31 control groups without any symptom,statistically. We also reviewed CT findings in 15 study groups. RESULTS: The mean rotary deformity in study groups was 6.1 degree(the standard deviation is 5.20), and the mean rotary deformity in control groups was 2.52 degree(the standard deviation is 2.16)(p <0.01) CONCLUSION: The rotary deformity can be accompanied with degenerative spondylolisthesis. We may consider the rotary deformity as a cause of symptomatic degenerative spondylolisthesis in case that any other cause is not detected.
Congenital Abnormalities* ; Spondylolisthesis*

OBJECTIVE:To evaluate the biodurability of the covering material in retrievable metallic stents covered with polycarbonate polyurethane. MATERIALS AND METHODS: Using a peristaltic pump at a constant rate of 1ml/min, bile was recirculated from a reservoir through a long tube containing four stents. Each of these was removed from the system every two weeks and a radial tensile strength test and scanning electron microscopy (SEM) were performed. Each stent, removed at 2, 4, 6 and 8 weeks, was compared with a control stent not exposed to bile juice. RESULTS: Gross examination showed that stents were intact at 2 weeks, but at 4, 6 and 8 weeks cracks were observed. The size of these increased gradually in accordance with the duration of exposure, and at 8 weeks several large holes in the polyurethane membrane were evident. With regard to radial tensile strength, extension and peak load at break were 84.47% and 10.030 N/mm, 54.90% and 6.769 N/mm, 16.55% and 2.452 N/mm, 11.21% and 1.373 N/mm at 0, 2, 4 and 6 weeks, respectively. Scanning electron microscopy at 2 weeks revealed intermittent pitting and cracking, and examination at 4, 6 and 8 weeks showed that the size of these defects was gradually increasing. CONCLUSION: When the polyurethane membrane was exposed to bile, biodegradation was first observed at week two and increased gradually according to the duration of exposure.
Bile Acids and Salts/physiology ; Biodegradation ; Hydrogen-Ion Concentration ; Microscopy, Electron, Scanning/*instrumentation ; Phantoms, Imaging ; *Polyurethanes ; *Stents ; Support, Non-U.S. Gov't ; Tensile Strength ; Time Factors

No abstract available.

No abstract available.
Cisterna Magna*

PURPOSE: To determine whether spontaneous a splenorenal shunt can be used as an imaging predictor of early renal hemodynamic changes in patients with cirrhosis. MATERIALS AND METHODS: The study included 82 cirrhotic patients and 41 control subjects. Three-phase CT was performed and CT attenuation values (Hounsfield units) of the renal cortex in three phases were measured to evaluate renal perfusion. Likelihood ratio tests for trend were conducted for age, presence of ascites, and Child's grade. RESULTS: The mean CT attenuation values of the renal cortex in cirrhotic patients were significantly lower than the values of control subjects in three phases: 153.3 +/- 37.9 versus 173.3 +/-25.2 in the arterial phase, 172.6 +/- 41.0 versus 197.6 +/- 26.5 in the portal phase and 136.9 +/- 26.0 versus 152.7 +/- 20.0 in the delayed phase, respectively. The mean CT attenuation value of cortices in patients with renal hypoperfusion was 119.9 +/- 11.8 in the portal phase. Child's class C (aOR: 58.4, 95% CI: 3.6-956.2; p < 0.01) and the presence of a renal shunt (aOR: 7.5, 95% CI: 1.8-30.5; p < 0.01) were associated with renal hypoperfusion. The incidence of renal hypoperfusion was associated with Child's grade (trend: p < 0.01), and not with the grade of ascites or age. CONCLUSION: A dilated spontaneous splenorenal shunt may be a risk factor for renal hypoperfusion in cirrhosis.
Ascites ; Fibrosis ; Hemodynamics ; Humans ; Incidence ; Liver ; Liver Cirrhosis ; Perfusion ; Risk Factors ; Splenorenal Shunt, Surgical

PURPOSE: To assess the safety and long term effectiveness of polyurethane-covered retrievable expandable nitinol stents in the treatment of benign and malignant tracheobronchial strictures. MATERIALS AND METHODS: Under fluoroscopic guidance, the stents were placed in 32 patients with dyspnea whose strictures were malignant in 15 cases and benign in 17. A stent was removed when complications occurred,or -electively- 2-6 months after placement in patients with benign strictures. The range of follow-up period was 1 -98 weeks (median, 47; range, 50) weeks. RESULTS: Stent placement was well tolerated in 30 patients. After placement, all 32 showed immediate symptom improvement and in none were complications such as ingrowth of a tumor or granulation tissue observed during the follow up period. Stent migration occurred in six patients. In one of six and four of five patients from whom, respectively, stents had been electively removed two and six months after placement, tracheo-bronchial restenosis did not occur during follow up. Second stents were placed in six patients in whom dyspnea recurred due to restenosis after elective stent removal. In two of these six, stents were removed six months after placement and dyspnea did not recur during follow up. CONCLUSION: The use of covered retrievable tracheobronchial stents is safe and feasible in the conservative treatment of patients with malignant tracheobronchial strictures as well as for selected patients with benign strictures.
Constriction, Pathologic* ; Dyspnea ; Follow-Up Studies* ; Granulation Tissue ; Humans ; Stents*

PURPOSE: To evaluate the usefulness of flexible covered stent in the treatment of acute colorectalobstruction secondary to colorectal carcinoma. MATERIALS AND METHODS: Flexible covered stents were placed in 11patients with clinical and radiologic signs of acute colonic obstruction secondary to colorectal carcinoma. Thepurposes of stent insertion were pre-operative bowel preparation in seven patients and palliative treatment infour. A fistula was present in two;in one this was between the proximal jejunum and colon, and the other wasrectovaginal. The usefulness of stent insertion for the purpose of preoperative bowel preparation was evaluatedaccording to the feasability and status of bowel preparation, as decided by the operator. Palliative treatment forthe relief of symptoms of acute bowel obstruction was evaluated according to the number and amount of defecation,bowel dilatation in simple abdomen radiography, and the presence of complications. RESULT: Bowel preparation forthe purpose of preoperative bowel cleansing was easy in seven patients;the fecal materials remaining in the colonpresented no problems during surgery. In one of four patients palliative treatment involved a colostomy;this wasdue to recurrent stent obstruction by fecal materials after three months, and in two other patients there wasstent obstruction after two and five months, respectively. The stent in one of four patients who underwentpalliative treatment was removed because of stent migration three days after insertion;the stents in two patientswith fistulas covered the fistulas successfully. Complications after stent insertion were anal pain in threepatients, anal bleeding in three and stent migration in one. CONCLUSION: The flexible covered stent was aneffective device for the relief of acute colonic obstruction secondary to malignant rectosigmoid neoplasia. Itallowed for single-stage operation and covered the fistula. We believe however that for further evaluation of theusefulness of this type of stent in long-term palliative treatment, a larger-scale study is needed.
Abdomen ; Colon ; Colorectal Neoplasms ; Dilatation ; Fistula ; Hemorrhage ; Humans ; Jejunum ; Palliative Care ; Radiography ; Stents*

PURPOSE: To compare breath-hold gadolinium enhanced MR angiography(MRA) with digital subtraction angiography. MATERIALS AND METHODS: Ten patients underwent angiography and breath-hold gadolinium enhanced MRA;the latterperformed at 1.5T with 3D FSPGR after a bolus injection of gadopentetate dimeglumine(0.4mmol/kg) RESULTS: Sevenof ten pathologic conditions(70%) evaluated by both techniques had a similar appearance. The conditions examinedwere as follows : the artery feeding renal cell carcinoma(n=2): renal artery stenosis(n=2); pulmonaryAVM(n=2);abdominal aortic aneurysm(n=1); atheromatous plaque in the lower abdominal aorta(n=1);an enlargedbronchial artery(n=1); and an aberrant renal artery(n=1). For evaluating an anatomic relationship, a reconstructed3D image obtained by MRA is more advantageous. CONCLUSION: Breath hold contrast enhanced MRA is a potentiallyuseful noninvasive screening method for detecting vascular abnormality of the aorta and its branches.
Angiography ; Angiography, Digital Subtraction ; Aorta ; Arteries ; Gadolinium ; Humans ; Mass Screening ; Renal Artery