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Dive into the research topics where G. Kenneth Johnson is active.

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Featured researches published by G. Kenneth Johnson.


Gastrointestinal Endoscopy | 1995

Treatment of pancreatic pseudocysts with ductal communication by transpapillary pancreatic duct endoprosthesis

Marc F. Catalano; Joseph E. Geenen; Michael J. Schmalz; G. Kenneth Johnson; Robert S. Dean; Walter J. Hogan

BACKGROUND Endoscopic treatment of pancreatic pseudocysts via cystenterostomy has been recognized as a successful treatment option in carefully selected patients. Pancreatic transpapillary stenting as an alternative treatment option in patients with pancreatic pseudocysts directly communicating with the main duct has received little consideration. The aim of the current study was to assess the safety and utility of transpapillary pancreatic endoprosthesis in the treatment of communicating pseudocysts. METHODS Twenty-one patients underwent placement of 33 transpapillary endoprostheses for the treatment of symptomatic pancreatic pseudocysts. All pseudocysts communicated with the main pancreatic duct and ranged in size from 3 to 9 cm (mean 6 cm). Eight patients had associated pancreatic duct strictures. RESULTS Stent placement was successful in all cases: 13 directly into the pseudocyst, 8 beyond the stricture but not into the pseudocyst. Initial resolution of pseudocysts was seen in 17 patients, with 16 patients free of pseudocyst recurrence at mean follow-up of 37 months. All patients with associated strictures were treated successfully. Factors predictive of success included presence of strictures, size of pseudocyst greater than or equal to 6 cm, location in the body of the pancreas, and duration of pseudocyst less than 6 months. Complications included one episode of mild pancreatitis. CONCLUSIONS Endoscopic treatment of symptomatic pancreatic pseudocysts with ductal communication by transpapillary pancreatic duct stenting is a safe, effective modality and should be considered a first line therapy.


Digestive Diseases and Sciences | 1989

Idiopathic recurrent pancreatitis

Rama P. Venu; Joseph E. Geenen; Walter J. Hogan; John Stone; G. Kenneth Johnson; Konrad H. Soergel

The cause of recurrent acute pancreatitis can be identified in the majority of patients. A small group of patients in whom an etiological association is not obvious is characterized as idiopathic recurrent pancreatitis (IRP). During the last seven years, we used endoscopic retrograde cholangiopancreatography (ERCP) and sphincter of Oddi (SO) manometric pressure studies to investigate 116 patients initially diagnosed as IRP. Forty-four of the 116 patients were found to have a demonstrable cause of their pancreatitis. Appropriate therapeutic intervention was carried out in 43 of these patients with a favorable outcome in the majority of patients noted during long-term follow-up.


Gastrointestinal Endoscopy | 1991

Endoscopic treatment of biliary tract strictures in sclerosing cholangitis: a larger series and recommendations for treatment

G. Kenneth Johnson; Joseph E. Geenen; Rama P. Venu; Michael J. Schmalz; Walter J. Hogan

We report a group of 35 patients with primary sclerosing cholangitis who had long-term follow-up after endoscopic treatment of major ductal strictures in the primary or secondary biliary ducts. Our patients were all symptomatic with ascending cholangitis or jaundice. There was significant improvement as measured by clinical parameters of hospitalization rates and laboratory data and comparable radiography. Long-term follow-up averaged 24 (+/- 2.8 months). We believe endoscopic treatment of sclerosing cholangitis should be attempted in selected symptomatic cases with major ductal strictures before liver transplantation.


Gastrointestinal Endoscopy | 1989

Endoscopic therapy for benign bile duct strictures

Dj Geenen; Joseph E. Geenen; Walter J. Hogan; Jeffrey Schenck; Rama P. Venu; G. Kenneth Johnson; Al Jackson

Endoscopic therapy was attempted in 25 patients with benign strictures of the bile duct. In 23 patients, treatment involved endoscopic balloon dilation of the stricture zone or balloon dilation plus endoprosthesis placement. In 22 of 25 patients (88%), there was benefit from the endoscopic treatment. In 20 of 23 patients, there was significant radiographic improvement (p less than 0.001) in the diameter of their stricture following endoscopic therapy. All patients with elevated liver enzymes demonstrated rapid improvement following treatment. There was no significant morbidity or mortality associated with endoscopic treatment of benign biliary tract strictures. Follow-up study (mean, 4 +/- 0.3 years) discloses no recurrence of symptoms or elevated enzymes indicative of recurrent strictures. The treatment of benign bile duct strictures by a combination therapy of balloon dilation and stent placement provides a safe and effective treatment modality and an alternative to operative intervention.


Gastrointestinal Endoscopy | 1995

A comparison of nonionic versus ionic contrast media : results of a prospective, multicenter study

G. Kenneth Johnson; Joseph E. Geenen; R. Bedford; John F. Johanson; Oliver W. Cass; Stuart Sherman; Walter J. Hogan; Michael Ryan; William B. Silverman; Steven A. Edmundowicz; Mark Payne

BACKGROUND Pancreatitis is one of the most common complications associated with ERCP. Multiple factors have been implicated for this potentially serious complication. Numerous suggestions for minimizing risks at ERCP have been offered, one of which is to use nonionic, low osmolarity contrast agents for pancreatic injection. Results of previous studies comparing different contrast media have been inconclusive. METHODS To evaluate the role contrast material plays in the development of post-ERCP pancreatitis, the Midwest Pancreaticobiliary Group performed a prospective double-blind controlled study. A total of 1,979 consecutive ERCP patients were enrolled, and 1,659 patients with pancreatic duct injections were divided into subgroups according to the complexity of the ERCP. Post-ERCP pancreatitis was compared between similar groups. Patients were randomized to receive injections of nonionic, low osmolarity contrast or standard ionic contrast media. RESULTS The overall incidence of post-procedural pancreatitis was 10.2%. Those with diagnostic ERCP had the lowest incidence at 5.6%. Therapeutic procedures (12.3%) and sphincter of Oddi manometry (15.2%) had higher rates. Those injected with standard (ionic) contrast had an incidence of 10.4% and after injection with lower osmolar (nonionic) contrast, there was a 10% post-procedural pancreatitis rate. CONCLUSIONS Patients with more complex procedures develop pancreatitis more frequently. The use of low osmolar (nonionic) contrast media does not decrease the incidence of post-ERCP pancreatitis.


Gastrointestinal Endoscopy | 1997

Evaluation of post-ERCP pancreatitis: potential causes noted during controlled study of differing contrast media

G. Kenneth Johnson; Joseph E. Geenen; John F. Johanson; Stuart Shermal; Walter J. Hogan; Oliver W. Cass

BACKGROUND Possible sources of post-ERCP pancreatitis were evaluated during a prospective, randomized, controlled study comparing different contrast media. METHODS A total of 1979 patients were randomized and subdivided into groups during the study. Patients were grouped for comparison depending on the type of procedure performed during ERCP. Diagnostic patients studied with pancreatograms (Group I) were compared with other groups, specifically, those not studied with pancreatograms (Group IV). All patients had subjective and objective estimates of the difficulty in cannulation of both ducts. The incidence of postprocedural pancreatitis was compared between and within each group. RESULTS In Group I there was a progressively higher incidence of pancreatitis with increased numbers of pancreatic duct injections. Patients with the highest (19.5%) frequency of pancreatitis received 10 or more injections into the pancreatic duct. Group I cases with difficult common bile duct cannulations had a higher frequency of post-ERCP pancreatitis (9.5%), as compared with the entire group (5.6%). CONCLUSIONS There was a higher incidence of pancreatitis associated with increased manipulation around the papillary orifice, especially with multiple pancreatic duct injections. There was also a slightly higher incidence of post-ERCP pancreatitis in cases with difficult common bile duct cannulation. Endoscopists are encouraged to evaluate and develop safer cannulation techniques that minimize the number of injections into the pancreatic duct and enhance selective cannulation.


Gastroenterology | 1990

Endoscopic retrograde brush cytology

Rama P. Venu; Joseph E. Geenen; Mukund Kini; Walter J. Hogan; Mark Payne; G. Kenneth Johnson; Michael J. Schmalz

Endoscopic retrograde cholangiopancreatography has been shown to be a very valuable adjunct in the diagnosis of malignancy involving the biliary and/or pancreatic ductal system. However, characteristic endoscopic retrograde cholangiopancreatography radiographic findings associated with malignant strictures are frequently not specific and cytological confirmation becomes essential for the diagnosis. Unfortunately, the current overall diagnostic yield of positive cytology in such circumstances ranges from 18%-56% depending on the technique. A new brush device has been designed which is uniquely adapted to pancreaticobiliary strictures of varying anatomical configurations. This study shows results using this new cytology brush in a series of 53 patients with pancreaticobiliary malignancy. A significant improvement in the cytological yield of tumor confirmation was obtained with a diagnostic sensitivity of 70% and specificity of 100% using the new brush technique.


Gastrointestinal Endoscopy | 1987

Endoscopic treatment of biliary duct strictures in sclerosing cholangitis: follow-up assessment of a new therapeutic approach

G. Kenneth Johnson; Joseph E. Geenen; Rama P. Venu; Walter J. Hogan

Endoscopic sphincterotomy was performed on 10 patients with sclerosing cholangitis to improve biliary tract drainage and to remove bile duct sludge and stones. In addition, Gruentzig-type balloons were placed endoscopically to dilate severe biliary duct strictures in eight of these patients, and endoprostheses were inserted to bridge high grade strictures in three patients. In order to assess the effectiveness of endoscopic treatment, we compared the number of hospitalizations for clinical episodes of cholangitis in this patient group for similar periods of time before and after therapy. Episodes of cholangitis requiring hospitalization decreased from 2.5 +/- 0.4 per patient in the 12 months prior to endoscopic therapy to 0.2 +/- 0.2 episodes per patient in the year following treatment and to 0.33 +/- 0.2 episodes per patient in the additional follow-up period during the second year. Liver function tests have improved significantly over the follow-up period of 19.1 +/- 2.6 months from the time of endoscopic treatment. The serum bilirubin decreased from 6.9 +/- 2.0 mg/dl to 2.7 +/- 1.4 mg/dl; serum alkaline phosphatase decreased from 959 +/- 214 IU to 385 +/- 89 IU; and serum transaminase decreased from 117 +/- 17 IU to 77 +/- 12 IU. Endoscopic treatment appears to be effective in patients with severe sclerosing cholangitis.


Gastrointestinal Endoscopy | 1999

Clinical presentation and short-term outcome of endoscopic therapy of patients with symptomatic incomplete pancreas divisum

L. Jacob; Joseph E. Geenen; Marc F. Catalano; G. Kenneth Johnson; Dj Geenen; Walter J. Hogan

BACKGROUND The clinical significance of incomplete pancreas divisum (IPD) has not been fully described. In this study we report the clinical presentation and results of endoscopic treatment of the 32 (0.6%) patients with IPD seen at our center over a 10-year period. METHODS The study population consisted of 24 women and 8 men (mean age 42 years, range 13 to 82 years). Ten (31%) patients presented with acute recurrent pancreatitis, 5 (16%) with chronic pancreatitis, and 3 (9%) with pancreatic type pain. Detailed history, laboratory tests, US, CT, and ERCP excluded other etiologies for their symptoms. The remaining 14 (44%) presented with biliary problems. The 18 symptomatic patients with IPD were treated as follows: 8 received dorsal duct stents, 3 underwent minor papilla endoscopic sphincterotomy and dorsal duct stent placement, 4 had minor papilla dilatation only, and 3 had ventral duct stents placed. RESULTS Patients were then followed for recurrence of pancreatitis and pancreatic-type pain. Mean follow-up was 15.5 months (range 3 to 30 months). Six (60%) of the patients with acute recurrent pancreatitis and 4 (80%) with chronic pancreatitis benefitted from the endoscopic therapy. However, only 1 (33%) of the patients with pancreatic-type pain benefitted. CONCLUSION The clinical presentation and response to endoscopic therapy of patients with ICP appeared to be similar to that of patients with complete pancreas divisum.


Gastrointestinal Endoscopy | 1987

Intraluminal radiation therapy for biliary tract malignancy--an endoscopic approach.

Rama P. Venu; Joseph E. Geenen; Walter J. Hogan; G. Kenneth Johnson; Kenneth M. Klein; John Stone

Carcinomas involving the biliary tract commonly lead to biliary tract obstruction. Most tumors are unresectable at the time of diagnosis, and palliative surgery for biliary decompression is associated with a mortality rate of 10% to 15% and a morbidity rate of 25% to 35%.1,2 Radiation therapy has been used for treating carcinoma involving the biliary tract with variable success.5 More recently, effective palliation has been accomplished by percutaneously or endoscopically placed biliary stents or prostheses. Intraluminal radiation therapy (ILRT) has been used to deliver radiation to the tumor site at several centers. However, to accomplish such intraluminal radiation therapy, an indwelling T-tube or percutaneously placed transhepatic catheter is necessary. We report a new technique for intraluminal hepatobiliary radiation therapy using an endoscopically placed nasobiliary catheter as the port for introducing the radiation source. This technique has a unique advantage of avoiding percutaneous puncture for placement of a catheter into the liver or a laparotomy for T -tube placement.

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Joseph E. Geenen

Medical College of Wisconsin

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Walter J. Hogan

Medical College of Wisconsin

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Rama P. Venu

Medical College of Wisconsin

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Michael J. Schmalz

Medical College of Wisconsin

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John Stone

Medical College of Wisconsin

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Konrad H. Soergel

Medical College of Wisconsin

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Aram V. Manoukian

Medical College of Wisconsin

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Dj Geenen

Medical College of Wisconsin

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John F. Johanson

Medical College of Wisconsin

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Marc F. Catalano

Medical College of Wisconsin

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