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Biomedical subjects

R H Hawes

Publications and source records attributed to R H Hawes.

At least 19 recordsLinked to original sources
PubMed1999

Esophageal cancer staging: improved accuracy by endoscopic ultrasound of celiac lymph nodes.

BACKGROUND: Clinical staging of esophageal cancer is required for optimal therapy but remains imprecise. Pathologic verification of involved lymph nodes could potentially direct treatment allocation. With the rising incidence of distal and gastroesophageal junction adenocarcinomas, assessment of the celiac axis lymph nodes (CLNs) becomes important because it is a common nodal drainage basin. Endoscopic ultrasound (EUS) permits evaluation of CLNs and biopsy by fine-needle aspiration. This study examined the usefulness of this staging tool. METHODS: A consecutive series of 62 patients with esophageal cancer considered resectable by computed tomographic scan underwent EUS for T and N staging and were retrospectively studied. A CLN visualized by EUS as greater than 5 mm was considered positive. Fine-needle aspiration of the CLN was performed routinely. Endoscopic ultrasound and computed tomographic staging were compared on the basis of pathologic verification of CLNs. RESULTS: It was possible to evaluate CLNs by EUS in 59 (95%) of 62 patients: positive in 19, negative in 40. In EUS-positive patients, fine-needle aspiration was positive in 15, falsely negative in 2, and not done in 2. By computed tomographic scan, CLNs were negative in 57 patients and positive in 2. The CLNs were positive in 23 of 54 patients eligible for CLN pathologic verification. All positive CLNs not identified by EUS (7 false-negative EUS) were microscopic foci in one or two nodes and were associated with T3 tumors. Sensitivity and specificity of EUS were 72% and 97%, respectively, compared with 8% and 100% for computed tomographic scan. When EUS identified CLNs, fine-needle aspiration confirmed positivity in 88% of cases. CONCLUSIONS: Endoscopic ultrasound with fine-needle aspiration is useful in the detection and confirmation of CLN metastasis. In T3 tumors of the distal esophagus, a negative EUS result does not substantiate absence of CLN disease. Endoscopic ultrasound with fine-needle aspiration may be important in guiding treatment for patients with distal adenocarcinoma and documenting disease before neoadjuvant therapy.

Adenocarcinoma↗
PubMed1999

Bile duct stones and laparoscopic cholecystectomy: a decision analysis to assess the roles of intraoperative cholangiography, EUS, and ERCP.

BACKGROUND: The least costly management strategy for patients undergoing laparoscopic cholecystectomy is unclear. METHODS: A decision model incorporating cost ratios, test accuracy, complication, and failure rates was used to determine the costs of 4 peri-laparoscopic cholecystectomy strategies: endoscopic retrograde cholangiopancreatography (ERCP), intraoperative cholangiography (IOCG), endoscopic ultrasound (EUS), and expectant management. RESULTS: Expert IOCG is least costly for intermediate-risk patients when the risk of stones is between 17% and 34%. If expert EUS is available, 0% to 10% ("low" risk) merits expectant management; 11% to 55% ("intermediate" risk) merits EUS; and greater than 55% ("high" risk) merits ERCP. Thresholds were most sensitive to changes in the risks of symptoms and complications due to retained stones; and to procedural costs, sensitivity, and success rates. Neither IOCG nor EUS appears likely to reduce overall costs unless their accuracy and success rates are greater than 90% and their procedural cost is less than 60% to 70% that of ERCP. When neither are available, ERCP is preferable when the risk of stones is greater than 22%. Thresholds were relatively insensitive to changes in the risk and severity of ERCP-induced pancreatitis. CONCLUSIONS: The least costly strategy for laparoscopic cholecystectomy patients depends primarily on the risk of stones and stone-related symptoms, but procedural costs and operator expertise are also critical.

Cholangiography↗
PubMed1999

Endoscopic injection of bleeding esophageal varices with a poly-N-acetyl glucosamine gel formulation in the canine portal hypertension model.

BACKGROUND: It has been shown that poly-N-acetyl glucosamine produces rapid hemostasis by stimulating erythrocyte aggregation. Endoscopic injection of this substance may be effective in the treatment of bleeding varices. METHODS: In eight heparinized dogs with a bleeding esophageal varix greater than 2 mm in diameter, 2.5% to 3.5% poly-N-acetyl glucosamine gel was injected intravariceally and paravariceally. Endoscopy, endosonography, and histopathology were performed at 1, 7, 21, and 90 days after injection. RESULTS: In all cases, the variceal hemorrhage was stopped with three to four injections of a mean total gel volume of 1.9 mL. No recurrence of bleeding, ulceration, or stricture formation occurred. Through replacement of the gel by connective tissue, the varix was permanently obliterated in its whole course in five cases and in more than 70% of its length in three cases. No embolization and no poly-N-acetyl glucosamine antibodies were detected. CONCLUSIONS: Endoscopic injection of bleeding esophageal varices in this animal model with the use of poly-N-acetyl glucosamine gel was an effective and safe method for stopping the hemorrhage and inducing permanent varix obliteration.

Acetylglucosamine↗
PubMed1999

Prospective assessment of the utility of EUS in the evaluation of gallstone pancreatitis.

BACKGROUND: The ability to identify common bile duct stones by noninvasive means in patients with acute biliary pancreatitis is limited. The aim of this study was to prospectively evaluate the ability of endosonography (EUS) to identify cholelithiasis and choledocholithiasis and predict disease severity in patients with nonalcoholic pancreatitis. METHODS: EUS was performed immediately before endoscopic retrograde cholangiopancreatography (ERCP) by separate blinded examiners within 72 hours of admission. Gallbladder findings were compared between EUS and transabdominal ultrasonography (US). Using endoscopic extraction of a bile duct stone as the reference standard for choledocholithiasis, the diagnostic yield of EUS was compared with transabdominal US and ERCP. Features identified during endosonographic imaging of the pancreas were correlated with length of hospitalization. RESULTS: Thirty-six patients were studied. EUS and transabdominal US were concordant in their interpretation of gallbladder findings in 92% of patients. The sensitivity of transabdominal US, EUS, and ERCP for identifying choledocholithiasis was 50%, 91%, and 92% and the accuracy was 83%, 97%, and 89%, respectively. Length of hospital stay was longer in patients with peripancreatic fluid (9.2 vs. 5.7 days, p < 0.1) and shorter in patients with coarse echo texture (2.6 vs. 7.2 days, p < 0.05) demonstrated on EUS. CONCLUSIONS: EUS can reliably identify cholelithiasis and is more sensitive than transabdominal US in detecting choledocholithiasis in patients with biliary pancreatitis. EUS may be used early in the management of patients with acute pancreatitis to select those who would benefit from endoscopic stone extraction. The utility of EUS for predicting pancreatitis severity requires further investigation.

Abdomen↗
PubMed1999

Diagnosis of pancreas divisum by endoscopic ultrasonography.

BACKGROUND AND STUDY AIMS: During pancreatobiliary imaging by endoscopic ultrasound (EUS) at the authors' institution, it is customary to attempt to obtain the "stack sign", where the bile duct and the pancreatic duct can be seen to run in parallel through the pancreatic head. We suspected that such a view may not be attainable in patients with pancreas divisum because of the short ventral pancreatic duct. The aim of the study was to investigate whether the presence of pancreas divisum could be suspected on the basis of EUS findings. PATIENTS AND METHODS: The stack sign is obtained by positioning the echo endoscope in the long scope position with the transducer in the duodenal bulb. The balloon is then inflated and advanced snugly into the apex of the bulb. From this position, the bile duct (closest to the transducer) and the pancreatic duct can be seen to run in parallel through the pancreatic head. We attempted to obtain a stack sign during EUS examinations of six patients with pancreas divisum. EUS was done in these patients to look for evidence of chronic pancreatitis and the pancreas divisum was confirmed by endoscopic retrograde pancreatography. An attempt to obtain the stack sign was also made in 30 patients who had EUS for pancreatobiliary indications but did not have pancreas divisum. RESULTS: In only two out of six patients with pancreas divisum (33 %) were we able to obtain a stack sign. This was significantly different from the rate of observation of a stack sign in 83.3 % (25/30) of patients who did not have pancreas divisum (P=0.04). Of the two patients with pancreas divisum in whom a stack sign was seen, the ventral duct was markedly dilated (6.6 mm) in one, and the other patient had an unusually large ventral pancreas. CONCLUSIONS: The absence of a stack sign during pancreatobiliary imaging by EUS may suggest the diagnosis of pancreas divisum.

Congenital Abnormalities↗
PubMed1999

Endoscopic ultrasound guided fine needle aspiration biopsy: a large single centre experience.

BACKGROUND: Endoscopic ultrasound guided fine needle aspiration biopsy (EUS-FNA) is a recent innovation in the evaluation of gastrointestinal and pulmonary malignancies. AIMS: To review the experience with EUS-FNA of a large single centre. METHODS: 333 consecutive patients underwent EUS-FNA. Follow up data were available on 327 lesions in 317 patients, including 160 lymph nodes, 144 pancreatic lesions, 15 extraintestinal masses, and eight intramural tumours. RESULTS: A primary diagnosis of malignancy was obtained by EUS-FNA in 62% of patients with clinically suspicious lesions. The overall accuracy of EUS-FNA for the diagnosis of malignancy was 86%, with sensitivity of 84% and specificity of 96%. With respect to lesion types, the sensitivity, specificity, and accuracy were 85%, 100%, and 89% for lymph nodes; 82%, 100%, and 85% for pancreatic lesions; 88%, 100%, and 90% for perirectal masses; and 50%, 25%, and 38% for intramural lesions, respectively. Compared with size and sonographic criteria, EUS-FNA in the evaluation of lymph nodes provided superior accuracy and specificity, without compromising sensitivity. Inadequate specimens were obtained from only six patients, including 3/5 with stromal tumors. Only one complication occurred. CONCLUSIONS: EUS-FNA is safe and can readily obtain tissue specimens adequate for cytopathological diagnoses. Compared with size and sonographic criteria, it is a superior modality for the detection of nodal metastases. While providing accurate diagnosis of pancreatic and perirectal malignancies, results suggest the technique is less useful for intramural lesions.

Adolescent↗
PubMed1998

Endoscopic electrohydraulic lithotripsy in the management of pancreatobiliary lithiasis.

BACKGROUND: Clinical evaluation of intraoperative endoscopy with electrohydraulic lithotripsy (EHL) in the management of 13 patients with pancreatobiliary lithiasis was undertaken. METHODS: Ten patients with chronic pancreatitis with intraductal lithiasis in the head and three with biliary lithiasis (one choledochal, one cystic, one right intrahepatic) underwent intraoperative endoscopy with EHL. Shock waves were applied by visual contact with a 3-Fr gauge EHL probe until all stones were fragmented and irrigated free. All pancreatitis patients had failed ERCP attempts to stent their pancreatic ducts secondary to ductal lithiasis. Patients with pancreatic stones underwent lateral pancreatojejunostomy. Biliary stone patients underwent laparoscopic cholecystectomy with common duct exploration (two cases) and open cholecystectomy with choledochoduodenostomy (one case). RESULTS: Intraductal stone eradication was successful in all patients. Transampullary visualization of the duodenum was achieved in eight cases. Average EHL time was 65 min. There was no evidence of postoperative pancreatitis, cholangitis, or retained common duct stones. CONCLUSION: Intraoperative pancreatobiliary endoscopy with EHL is safe and effective in the eradication of pancreatic and bile duct stones. This novel technique represents a valuable adjunct in the management of chronic fibrocalcific pancreatitis with ductal lithiasis in the head region and in the open and laparoscopic management of intra- and extrahepatic bile duct stones.

Adult↗
PubMed1998

Pancreatic stenting prevents pancreatitis after biliary sphincterotomy in patients with sphincter of Oddi dysfunction.

BACKGROUND & AIMS: Patients with sphincter of Oddi dysfunction are at high risk of developing pancreatitis after endoscopic biliary sphincterotomy. Impaired pancreatic drainage caused by pancreatic sphincter hypertension is the likely explanation for this increased risk. A prospective, randomized controlled trial was conducted to determine if ductal drainage with pancreatic stenting protects against pancreatitis after biliary sphincterotomy in patients with pancreatic sphincter hypertension. METHODS: Eligible patients with pancreatic sphincter hypertension were randomized to groups with pancreatic duct stents (n = 41) or no stents (n = 39) after biliary sphincterotomy. The primary measured outcome was pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). RESULTS: Pancreatic stenting significantly decreased the risk of pancreatitis from 26% to 7% (10 of 39 in the no stent group and 3 of 41 in the stent group; P = 0.03). Only 1 patient in the stent group developed pancreatitis after sphincterotomy, and 2 others developed pancreatitis at the time of stent extraction. Patients in the no stent group were 10 times more likely to develop pancreatitis immediately after sphincterotomy than those in the stent group (relative risk, 10.5; 95% confidence interval, 1.4-78.3). CONCLUSIONS: Pancreatic duct stenting protects significantly against post-ERCP pancreatitis in patients with pancreatic sphincter hypertension undergoing biliary sphincterotomy. Stenting of the pancreatic duct should be strongly considered after biliary sphincterotomy for sphincter of Oddi dysfunction; pancreatic sphincter of Oddi manometry identifies which high-risk patients may benefit from pancreatic stenting.

Adult↗
PubMed1998

Clinical implications of endoluminal ultrasonography using through-the-scope catheter probes.

BACKGROUND: Ultrasound catheter probe-assisted endosonography is a relatively new technique. The aim of this prospective multicenter study was to determine its potential clinical impact by assessing changes in diagnostic and therapeutic management affected by catheter probes compared with ultrasound endoscopes. METHODS: Endosonographers at three centers selected theoretic diagnostic and therapeutic plans that would be followed if neither catheter probes nor ultrasound endoscopes were available. Patients with suitable lesions underwent endosonography with catheter probes followed by an ultrasound endoscope. Diagnostic and therapeutic plans were noted after each examination. RESULTS: Sixty-six patients, of whom 15 had a stenotic esophageal cancer, 39 had a mucosal or submucosal lesion, and 12 had a stricture of the pancreaticobiliary system or the gastrointestinal tract, were enrolled. If neither form of endosonography were available, invasive or surgical diagnostic procedures would have been performed on 23 (35%) patients and surgical therapy would have been planned in 31 (47%) patients. Catheter probe-assisted ultrasonography and endoscopic ultrasonography led to a less invasive diagnostic plan in 11 (16%) and 12 (18%) patients and a less invasive therapeutic plan in 10 (15%) and 14 (21%) patients, respectively (p > 0.1 for differences). CONCLUSIONS: Catheter probe-assisted endosonography has a modest effect on diagnostic and therapeutic management, comparable with endoscopic ultrasonography in the same patients. The vast majority of effected changes are toward less invasive management.

Digestive System Neoplasms↗
PubMed1998

Prospective assessment of the ability of endoscopic ultrasound to diagnose, exclude, or establish the severity of chronic pancreatitis found by endoscopic retrograde cholangiopancreatography.

BACKGROUND: Our aim was to verify endoscopic ultrasound (EUS) accuracy to diagnose, rule out, and establish the severity of chronic pancreatitis found by endoscopic retrograde cholangiopancreatography (ERCP). METHODS: Patients undergoing ERCP for unexplained abdominal pain and/or suspected chronic pancreatitis underwent EUS. EUS was performed by experienced operators who were aware of the history but blinded to ERCP results. Chronic pancreatitis was defined using the Cambridge classification: 0 to 1 = "normal," 2 to 4 = "all chronic pancreatitis," 3 to 4 = "moderate to severe chronic pancreatitis." The number of EUS criteria required to obtain sensitivity, specificity, positive and negative predictive values > or = 85% was determined. EUS criteria for chronic pancreatitis are hyperechoic foci, hyperechoic strands, lobularity, hyperechoic duct, irregular duct, visible side-branches, ductal dilation, calcification, and cysts. RESULTS: One hundred twenty-six patients underwent EUS and ERCP. EUS was highly sensitive and specific (> 85%) depending on the number of criteria present. Chronic pancreatitis is likely (PPV > 85%) when more than two criteria (for "all chronic pancreatitis") and more than six criteria (for "moderate to severe chronic pancreatitis") are present. "Moderate to severe chronic pancreatitis" is unlikely (NPV > 85%) when fewer than three criteria are present. Independent predictors of chronic pancreatitis were "calcification" (p = 0.000001), history of alcohol abuse (p = 0.002), and the total number of EUS criteria (p = 0.008). CONCLUSIONS: EUS can accurately diagnose, rule out, and establish the severity of chronic pancreatitis found by ERCP.

Adult↗
PubMed1998

Local staging of anal and distal colorectal tumors with the magnetic resonance endoscope.

BACKGROUND: We prospectively assessed the feasibility and accuracy of endoscopic magnetic resonance (EMR) scanning in the local staging of anal and colorectal cancer as compared to endosonography. METHODS: Fifteen patients with biopsy-proven anal (n = 2), rectal (n = 11), and distal colonic (n = 2) cancer underwent endosonography followed by EMR imaging. Scans were acquired using the magnetic resonance receiver coil incorporated into the tip of the non-ferromagnetic endoscope. Blinded to endosonography results, two radiologists interpreted the EMR images using the TNM system. Staging results were compared to endosonography in all patients and to histopathology in the 13 colorectal cases. RESULTS: EMR imaging, well tolerated in all patients, correlated with endosonography in 10 of 15 and 12 of 15 cases for T- and N-staging, respectively. In the 13 colorectal patients with available histopathology, accuracy of EMR and of endosonography in T-staging was 77% and 85%, respectively; N-staging accuracy was 62% for both. CONCLUSIONS: For anal and distal colorectal neoplasms, EMR imaging is feasible and provides local staging comparable to endosonography.

Adenocarcinoma↗
PubMed1998

A swine model for teaching endoscopic ultrasound (EUS) imaging and intervention under EUS guidance.

BACKGROUND AND STUDY AIMS: Endoscopic ultrasonography (EUS) has evolved into a clinically useful imaging modality. Widespread application of EUS has been hampered by the long learning curve and the paucity of training programs. We report here our efforts to develop an animal model for teaching endoscopic ultrasound. MATERIALS AND METHODS: The protocol for performing endoscopic ultrasound in live pigs included general anesthesia, endotracheal intubation, and mechanical ventilatory support. An echo-endoscope was then inserted into the pig gastrointestinal tract, and attempts were made to obtain ultrasound images that were comparable to human endoscopic ultrasound images. Intervention under EUS guidance was then attempted in the swine. RESULTS: It was possible to image the esophageal and gastric wall, pancreas, aorta, celiac artery, superior mesenteric artery, liver, and portal vein. The images obtained were analogous to human endoscopic ultrasound images. EUS-guided interventional techniques were also carried out, including EUS-guided fine-needle aspiration and celiac plexus neurolysis. CONCLUSIONS: A swine model appears to be useful for hands-on teaching in endoscopic ultrasound imaging and intervention under endoscopic ultrasound guidance.

Animals↗