Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Douglas A. Howell is active.

Publication


Featured researches published by Douglas A. Howell.


Gastrointestinal Endoscopy | 2004

Endoscopic management of adenoma of the major duodenal papilla

Marc F. Catalano; Jeffrey D. Linder; Amitabh Chak; Michael V. Sivak; Isaac Raijman; Joseph E. Geenen; Douglas A. Howell

BACKGROUND It is well established that adenoma of the major duodenal papilla has a potential for malignant transformation. Standard treatment has been surgical (duodenotomy/local resection, pancreaticoduodenectomy). Endoscopic management is described, but there is no established consensus regarding the approach to papillectomy or the need for surveillance. This study describes endoscopic management and long-term follow-up of papillary tumors by 4 groups of expert pancreaticobiliary endoscopists. METHODS Consecutive patients with papillary tumors referred to 4 pancreaticobiliary endoscopy centers for evaluation for endoscopic papillectomy were reviewed. For each patient, an extensive questionnaire was completed, which included 19 preoperative and 15 postoperative data points. A total of 103 patients (53 women, 50 men, age range 24-93) who underwent attempted endoscopic resection were included. Of these, 72 had sporadic adenoma, and the remaining patients had familial adenomatous polyposis, including Gardners variant. Presenting symptoms were jaundice/cholangitis/pain (n=59), pancreatitis (n=18), and bleeding (n=12). Twenty-six patients were asymptomatic. RESULTS Endoscopic treatment was successful, long term, in 83 patients (80%) and failed (initial failure or recurrent tumor) in 20 (20%) patients. Success was significantly associated with older age (54.7 [16.6] vs. 46.6 [21.7] years; p=0.08) and smaller lesions (21.1 [8.3] vs. 29.7 [7.2] mm; p<0.0001). Success rate was higher for sporadic lesions compared with genetically determined lesions (63 of 72 [86%] vs. 20 of 31 [67%]; p=0.02). There were 10 initial failures, which was more common for sporadic lesions (7 of 10). The overall success rate for papillectomy was similar in patients who had adjuvant thermal ablation (81%) compared with those who did not (78%). However, recurrence (n=10) was more common in the former group (9 of 10, [90%]; p=0.22). Complications (n=10) included acute pancreatitis (n=5), bleeding (n=2), and late papillary stenosis (n=3). Acute pancreatitis was more common in patients who did not have pancreatic duct stents placed (17% vs. 3.3%). Papillary stenosis was more frequent without short-term pancreatic duct stent placement (15.4% vs. 1.1%), although the difference was not statistically significant, because this complication was infrequent. CONCLUSIONS Endoscopic treatment of papillary adenoma in selected patients appears to be highly successful. The majority can undergo complete resection after ERCP. In expert hands, complications are infrequent and may be avoided by routine placement of a pancreatic duct stent.


Gastrointestinal Endoscopy | 1998

Endoscopic pancreatic sphincterotomy: indications, outcome, and a safe stentless technique

E. Elton; Douglas A. Howell; Willis G. Parsons; T. Qaseem; Brian L. Hanson

BACKGROUND Endoscopic pancreatic sphincterotomy is less widely practiced than biliary sphincterotomy, in part because of the lack of firm data regarding its indications and safety. In addition, recent reports of ductal and parenchymal changes occurring after pancreatic stenting raise concerns about the standard practice of stent placement at the time of pancreatic sphincterotomy. We report our experience with pancreatic sphincterotomy and describe the use of a technique involving overnight nasopancreatic drainage rather than stenting. METHODS We reviewed the records of the 164 pancreatic sphincterotomies performed on 160 patients at our institution between January 1, 1991, and October 1, 1996, comparing procedures done with overnight nasopancreatic catheter placement with those done with stenting or no drainage. We also examined the long-term clinical outcome of patients after pancreatic sphincterotomy. RESULTS Of the 164 sphincterotomies, 98 were done with overnight nasopancreatic drainage, 50 with stent placement, and 16 with no drainage. Complications (all pancreatitis) were significantly more frequent in the group with no drainage (12.5%) as compared with those with drainage (0.7%); p < 0.003. Nasopancreatic drainage was as safe as stent placement, with no complications after 98 procedures. Pancreatic sphincterotomy was effective when used as primary therapy, with 64% of patients so treated experiencing complete and long-lasting resolution of symptoms after the procedure. CONCLUSIONS Pancreatic sphincterotomy is safe and effective, although pancreatic drainage is required to reduce the incidence of pancreatitis. Overnight nasopancreatic drainage is the method of choice, as it carries as low a complication rate as stent placement, but without the need for a repeat procedure, and presumably without the risk of ductal and parenchymal damage.


Gastrointestinal Endoscopy | 2013

A multicenter, U.S. experience of single-balloon, double-balloon, and rotational overtube–assisted enteroscopy ERCP in patients with surgically altered pancreaticobiliary anatomy (with video)

Raj J. Shah; Maximiliano Smolkin; Roy D. Yen; Andrew S. Ross; Richard A. Kozarek; Douglas A. Howell; Gennadiy Bakis; Sreenivasan S. Jonnalagadda; Abed Al-Lehibi; Al Hardy; Douglas R. Morgan; Amrita Sethi; Peter D. Stevens; Paul Akerman; Shyam Thakkar; Brian C. Brauer

BACKGROUND Data on overtube-assisted enteroscopy to facilitate ERCP in patients with surgically altered pancreaticobiliary anatomy, or long-limb surgical bypass, is limited. OBJECTIVE To evaluate and compare ERCP success by using single-balloon (SBE), double-balloon (DBE), or rotational overtube enteroscopy. DESIGN Consecutive patients identified retrospectively. SETTING Eight U.S. referral centers. PATIENTS Long-limb surgical bypass patients with suspected pancreaticobiliary diseases. INTERVENTION Overtube-assisted enteroscopy ERCP. MAIN OUTCOME MEASUREMENTS Enteroscopy success: visualizing the pancreaticobiliary-enteric anastomosis or papilla. ERCP success: completing the intended pancreaticobiliary intervention. Clinical success: greater than 50% reduction in abdominal pain or level of hepatic enzyme elevations or resolution of jaundice. RESULTS From January 2008 through October 2009, 129 patients had 180 enteroscopy-ERCPs. Anatomy was Roux-en-Y: gastric bypass (n = 63), hepaticojejunostomy (n = 45), postgastrectomy (n = 6), Whipple procedure (n = 10), and other (n = 5). ERCP success was 81 of 129 (63%). Enteroscopy success: 92 of 129 (71%), of whom 81 of 92 (88%) achieved ERCP success. Reasons for ERCP failure (n = 48): afferent limb entered but pancreaticobiliary anastomosis and/or papilla not reached (n = 23), cannulation failure (n = 11), afferent limb angulation (n = 8), and jejunojejunostomy not identified (n = 6). Select interventions: anastomotic stricturoplasty (cautery ± dilation, n = 16), stone removal (n = 21), stent (n = 25), and direct cholangioscopy (n = 11). ERCP success rates were similar between Roux-en-Y gastric bypass and other long-limb surgical bypass and among SBE, DBE, and rotational overtube enteroscopy. Complications were 16 of 129, 12.4%. LIMITATIONS Retrospective study. CONCLUSION (1) ERCP is successful in nearly two-thirds of long-limb surgical bypass patients and in 88% when the papilla or pancreaticobiliary-enteric anastomosis is reached. (2) Enteroscopy success in long-limb surgical bypass is similar among SBE, DBE, and rotational overtube enteroscopy methods. (3) Referral of long-limb surgical bypass patients who require ERCP to high-volume institutions may be considered before more invasive percutaneous or surgical alternatives.


Gastrointestinal Endoscopy | 1992

Endoscopic needle aspiration biopsy at ERCP in the diagnosis of biliary strictures.

Douglas A. Howell; R.P. Beveridge; John J. Bosco; M. Jones

We have developed a ball-tipped catheter with a retractable 22-gauge, 7-mm long needle to perform endoscopic needle aspiration (ENA) for cytology and compared this technique to brush cytology of malignant-appearing biliary strictures during ERCP. Of 31 patients, 26 had proven malignant strictures involving the common bile duct and 5 had benign lesions. All 31 patients had ENA and 29 were brushed. Positive ENAs were obtained in 16 of 26 patients (61.5%) and positive brushings in 2 of 24 (8.3%). With the addition of two suspicious ENAs for pancreatic adenocarcinoma, 73% of patients had positive or suspicious cytology for malignancy by combined ENA and brush with a specificity of 100%. Although ENA appeared to be more sensitive in diagnosing cholangiocarcinoma, it proved to be most effective in the diagnosis of pancreatic adenocarcinoma when compared with brush cytology. One patient with cholangiocarcinoma in our series was diagnosed by brush cytology only, with a negative ENA, supporting our recommendation of using both endoscopic brushings and ENA for cytology when evaluating biliary strictures.


Gastrointestinal Endoscopy | 1998

Diagnostic and therapeutic ERCP using an enteroscope and a pediatric colonoscope in long-limb surgical bypass patients

E. Elton; Brian L. Hanson; T. Qaseem; Douglas A. Howell

Diagnostic and therapeutic ERCP has nearly the same high success and low complication rates in Billroth II gastroenterostomy patients as in patients with normal anatomy.1,2 However, long-limb surgical bypasses have, in general, precluded endoscopic access for retrograde cannulation. Patients who have undergone these operations have usually been evaluated and treated with interventional radiologic procedures or surgery. With the advent and refinement of push enteroscopes and pediatric colonoscopes, however, endoscopic access to the papilla is now possible. We describe here our initial experience in using these endoscopes for retrograde cannulation and therapeutic ERCP in patients who have undergone long-limb bypasses.


Gastrointestinal Endoscopy | 2009

Comparative performance of uncoated, self-expanding metal biliary stents of different designs in 2 diameters: final results of an international multicenter, randomized, controlled trial.

Burr J. Loew; Douglas A. Howell; Michael K. Sanders; David J. Desilets; Paul P. Kortan; Gary R. May; Raj J. Shah; Yang K Chen; Willis G. Parsons; Robert H Hawes; Peter B Cotton; Adam Slivka; Jawad Ahmad; Glen A. Lehman; Stuart Sherman; Horst Neuhaus; Brigitte Schumacher

BACKGROUND The Wallstent has remained the industry standard for biliary self-expanding metal stents (SEMSs). Recently, stents of differing designs, compositions, and diameters have been developed. OBJECTIVE To compare the new nitinol 6-mm and 10-mm Zilver stents with the 10-mm stainless steel Wallstent and determine the mechanism of obstruction. DESIGN Randomized, prospective, controlled study. SETTING Nine centers experienced in SEMS placement during ERCP. PATIENTS A total of 241 patients presenting between September 2003 and December 2005 with unresectable malignant biliary strictures at least 2 cm distal to the bifurcation. MAIN OUTCOME MEASUREMENT Stent occlusions requiring reintervention and death. RESULTS At interim analysis, a significant increase in occlusions was noted in the 6-mm Zilver group at the P = .04 level, resulting in arm closure but continued follow-up. Final study arms were 64, 88, and 89 patients receiving a 6-mm Zilver, 10-mm Zilver, and 10-mm Wallstent, respectively. Stent occlusions occurred in 25 (39.1%) of the patients in the 6-mm Zilver arm, 21 (23.9%) of the patients in the 10-mm Zilver arm, and 19 (21.4%) of the patients in the 10-mm Wallstent arm (P = .02). The mean number of days of stent patency were 142.9, 185.8, and 186.7, respectively (P = .057). No differences were noted in secondary endpoints, and the study was ended at the 95% censored study endpoints. Biopsy specimens of ingrowth occlusive tissue revealed that 56% were caused by benign epithelial hyperplasia. CONCLUSIONS SEMS occlusions were much more frequent with a 6-mm diameter SEMS and equivalent in the two 10-mm arms despite major differences in stent design, material, and expansion, suggesting that diameter is the critical feature. Malignant tumor ingrowth produced only a minority of the documented occlusions.


Annals of Internal Medicine | 1988

Odynophagia from aphthous ulcers of the pharynx and esophagus in the acquired immunodeficiency syndrome (AIDS).

Michael C. Bach; August J. Valenti; Douglas A. Howell; Thomas J. Smith

Excerpt Nonspecific aphthous ulcers of the mouth are common in immunocompetent patients (1). The ulcers are self-limited, rarely progress to involve the hypopharynx or esophagus, and do not usually...


Annals of Surgery | 1998

Endoscopic Sphincterotomy for Stones By Experts Is Safe, Even in Younger Patients With Normal Ducts

Peter B. Cotton; Joseph E. Geenen; Stuart Sherman; John T. Cunningham; Douglas A. Howell; David L. Carr-Locke; Nicholas Nickl; Robert H. Hawes; Glen A. Lehman; A. Ferrari; Adam Slivka; David R. Lichtenstein; John Baillie; Paul S. Jowell; Laura M. Lail; Harry Evangelou; John J. Bosco; Brian L. Hanson; Brenda J. Hoffman; Soroya Rahaman; Rene Male

OBJECTIVE To provide current information on the risks of endoscopic sphincterotomy for stone. SUMMARY BACKGROUND DATA In recent years (since the popularity of laparoscopic cholecystectomy), endoscopic sphincterotomy has been used increasingly for the management of bile duct stones in relatively young and healthy patients. The validity of this trend has been questioned using data on short-term complications derived from earlier decades that involved more elderly and high-risk patients. METHODS Seven academic centers collected data prospectively using a common database. Complications within 30 days of the procedures were documented by standard criteria. RESULTS Of 1921 patients, 112 (5.8%) developed complications; two thirds of these events were graded as mild (<3 days in hospital). There was no evidence of increased risk in younger patients or in those with smaller bile ducts. There was only one severe complication and there were no fatalities in 238 patients age <60, with bile duct diameters of <9 mm. CONCLUSION Sphincterotomy for stones can be performed very safely by experienced endoscopists.


The American Journal of Gastroenterology | 2007

Mechanical lithotripsy of pancreatic and biliary stones: Complications and available treatment options collected from expert centers

Miriam Thomas; Douglas A. Howell; David L. Carr-Locke; C. Mel Wilcox; Amitabh Chak; Isaac Raijman; James L. Watkins; Michael J. Schmalz; Joseph E. Geenen; Marc F. Catalano

INTRODUCTION:IPD and common bile duct (CBD) stones often require mechanical lithotripsy (ML) at ERCP for successful extraction. The frequency and spectrum of complications is not well described in the literature.AIM: To describe the frequency and spectrum of complications of ML.METHODS: A comprehensive retrospective review of cases requiring ML of large or resistant PC and/or CBD stones using a 46-point data questionnaire on type(s) of complication, treatment attempted, and success of treatment. The study involved 7 tertiary referral centers with 712 ML cases (643 biliary and 69 pancreatic).RESULTS: Overall incidence of complications were: 4–4% (31/712); 23/643 biliary, 8/69 pancreatic; 21 single, 10 multiple. Biliary complications: trapped (TR)/broken (BR) basket (N = 11), wire fracture (FX) (N = 8), broken (BR) handle (N = 7), perforation/duct injury (N = 3). Pancreatic complications: TR/BR basket (N = 7), wire FX (N = 4), BR handle (N = 5), pancreatic duct leak (N = 1). Endoscopic intervention successfully treated complications in 29/31 cases (93.5%). Biliary group treatments: sphincterotomy (ES) extension (N = 7), electrohydraulic lithotripsy (EHL) (N = 11), stent (N = 3), per-oral Soehendra lithotripsy (N = 8), surgery (N = 1), extracorporeal lithotripsy (N = 5), and dislodge stones/change basket (N = 4). Pancreatic group treatments: ES extension (N = 3), EHL (N = 2), stent (N = 5), Soehendra lithotriptor (N = 4), dislodge stones/change basket (N = 2), extracorporeal lithotripsy (ECL) (N = 1), surgery (N = 1). Perforated viscus patient died at 30 days.CONCLUSION: The majority of ML in expert centers involved the bile duct. The complication rate of pancreatic ML is threefold greater than biliary lithotripsy. The most frequent complication of biliary and pancreatic ML is trapped/broken baskets. Extension of ES and EHL are the most frequently utilized treatment options.


Annals of Internal Medicine | 1990

Aphthous ulceration of the gastrointestinal tract in patients with the acquired immunodeficiency syndrome (AIDS).

Michael C. Bach; Douglas A. Howell; August J. Valenti; Thomas J. Smith; Dean L. Winslow

Excerpt Patients with steroid-responsive, severe aphthous ulceration involving the mouth, hypopharynx, and esophagus have been described in a previous report (1). In these patients, serious morbidi...

Collaboration


Dive into the Douglas A. Howell's collaboration.

Top Co-Authors

Avatar

Christopher Lawrence

Medical University of South Carolina

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge