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Dive into the research topics where Michael J. Schmalz is active.

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Featured researches published by Michael J. Schmalz.


Gastrointestinal Endoscopy | 1992

Incidence and risk factors for biliary and pancreatic stent migration

John F. Johanson; Michael J. Schmalz; Joseph E. Geenen

Endoprostheses are commonly used in the treatment of biliary and pancreatic disorders. The frequency of and potential risk factors for stent migration, however, remain largely unknown. From January 1986 to June 1990, 807 biliary and pancreatic stents were placed at our institution. Our study analyzed the occurrence of stent migration among the 589 stents for which follow-up data were available. Results demonstrated incidence rates of 4.9 and 5.9% for proximal (into the duct) and distal (out of the duct) biliary stent migration, respectively. Likewise, incidence rates of 5.2 and 7.5% were observed for proximal and distal pancreatic stent migration, respectively. Malignant strictures, larger diameter stents, and shorter stents were significantly associated with proximal biliary stent migration. Sphincter of Oddi dysfunction and longer stents were associated with proximal pancreatic stent migration. Migration of stents out of the common bile duct occurred more frequently in papillary stenosis. No other significant risk factors for distal migration were found. These results indicate that stent migration is an important complication. Multiple risk factors were associated with stent migration and need to be considered in the development of new stent types.


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.


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.


Journal of Pediatric Gastroenterology and Nutrition | 1993

The diagnostic and therapeutic role of endoscopic retrograde cholangiopancreatography in children.

Christopher W. Brown; Steven L. Werlin; Joseph E. Geenen; Michael J. Schmalz

We performed 121 endoscopic retrograde cholangiopancreatographies (ERCPs) in 92 patients (60 girls and 32 boys), aged 4 months to 19 years, as part of diagnostic evaluation for suspected pancreatic or biliary tract disease or as therapeutic intervention. ERCP was successful in 116 attempts. The most common indications were recurrent pancreatitis (35 children), nonresolving acute pancreatitis (20), unexplained elevated amylase or lipase (19), postcholecystectomy syndrome (14), and elevated biliary tract enzymes (12). One hundred and one ERCPs were performed for more than one indication. The most common findings included chronic pancreatitis (26 cases), pancreas divisum (14), dilated pancreatic duct (10), gallstones or sludge (8), and abnormal common bile duct (8). Complications were uncommon and usually minor. ERCP is a safe and helpful procedure in the evaluation of suspected pancreatic and biliary tract disease in children and frequently allows for nonoperative treatment of these disorders.


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.


Gastrointestinal Endoscopy | 1998

Endoscopic retrieval of proximally migrated biliary and pancreatic stents: experience of a large referral center

Sandeep Lahoti; Marc F. Catalano; Joseph E. Geenen; Michael J. Schmalz

BACKGROUND Proximal migration of a biliary or pancreatic stent is an infrequent event but its management can be technically challenging. METHODS Review of all cases of proximally migrated biliary and pancreatic stents over a 10-year period at a referral pancreatic-biliary center. Data abstracted from patient records included indication for stenting, method of presentation, success of attempt, and method used. Successful methods were determined by reviewing procedure reports. Follow-up was attempted in all patients in whom stent retrieval had failed. RESULTS Thirty-three proximally migrated bile duct stents, and 26 proximally migrated pancreatic duct stents were identified. Most of the patients were without symptoms. Eighty-five percent of common bile duct stents and 80% of pancreatic duct stents were successfully extracted endoscopically. Seventy-one percent (34 of 48) were retrieved with a basket or balloon. Of the stents not retrieved, two patients did not return for repeat ERCP, three patients with malignant common bile duct strictures were managed with placement of a second stent, three patients with pancreatic duct stents have remained without symptoms with no further retrieval attempts, and three patients with proximally migrated pancreatic duct stents required surgery because of pain and failure of multiple endoscopic retrieval attempts. CONCLUSION Over 80% of proximally migrated bile duct and pancreatic duct stents may be extracted endoscopically. Few patients will require surgery.


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 | 1993

Endoscopic treatment of problems encountered after cholecystectomy

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

With the advent of laparoscopic cholecystectomy, a number of patients with various postprocedure problems have been referred for endoscopic management. Thirty-five patients were evaluated. The group included 26 women and 9 men, ages 24 to 90 years (mean, 50 years). Twenty-five patients with retained common bile duct stones were successfully treated with endoscopic sphincterotomy and balloon or basket removal. Three patients with bile duct strictures had balloon dilation and endoprosthesis placement and were free of signs of obstruction on 9-month follow-up. Bile leaks were treated successfully with endoscopic sphincterotomy and endoprosthesis placement. Two patients with bile duct leaks and biloma formation required percutaneous or surgical drainage in addition to endoscopic treatment. Three patients had more than one complication. Two patients had strictures with retained stones above the stricture; dilation of the stricture was performed and the stones were removed. One patient with the complication of biliary leak and a long, irregular stricture was treated temporarily by sphincterotomy and stent placement while awaiting surgery. Therapeutic biliary endoscopy is a valuable, minimally invasive alternative to surgery in patients with problems arising after laparoscopic cholecystectomy.


Gastrointestinal Endoscopy | 1993

Simple modification of a pancreatic duct stent to prevent proximal migration

John F. Johanson; Michael J. Schmalz; Joseph E. Geenen

1. Tada M, Karita M, Yanai H, Takemoto T. Treatment of early gastric cancer using strip biopsy, a new technique for jumbo biopsy. In: Takemoto T, Kawai K, eds. Recent topics of digestive endoscopy. Tokyo: Excerpta Medica, 1987:137-42. 2. Takekoshi T, Fujii A, Takagi K. Indication for endoscopic double-snare polypectomy (EDSP) [in Japanese]. Stomach Intest 1988;23:387-98. 3. Morson BC, Bussey HJR, Samoorian S. Policy of local excision for early cancer of the colorectum. Gut 1977;18:1045-50. 4. Inoue H, Endo M. Endoscopic esophageal mucosal resection using a transparent tube. Surg Endosc 1990;4:198-201. 5. Stiegmann GV, Cambre T, Sun JH. A new endoscopic elastic band ligating device. Gastrointest Endosc 1986;32:230-3. 6. Endo M, Takeshita K, Yoshida M. How can we diagnose the


Gastrointestinal Endoscopy | 1993

The incidence of post-sphincterotomy stenosis in group II patients with sphincter of Oddi dysfunction.

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

Patients with group II sphincter of Oddi dysfunction documented by elevated sphincter of Oddi pressure improve after endoscopic sphincterotomy. A large group II population was studied to determine the incidence of post-endoscopic sphincterotomy stenosis. Eighty-five patients (82 women and 3 men), ages 21 to 88 years (mean, 50 years), fulfilled the clinical criteria for group II sphincter of Oddi dysfunction; each had an elevated basal sphincter of Oddi pressure (> or = 40 mm Hg), and received endoscopic sphincterotomy. These patients were observed for a mean of 7 +/- 3 years. Four patients re-presented with clinical findings suggestive of recurrent sphincter of Oddi dysfunction; all were found to have a basal sphincter of Oddi pressure greater than or equal to 40 mm Hg. Symptoms re-developed within 4 months after endoscopic sphincterotomy (mean, 3.3 months). Endoscopic sphincterotomy was repeated in all four patients with one endoscopically treated complication. On 25-month mean follow-up, none of the patients had further signs or symptoms of papillary stenosis. Endoscopic sphincterotomy in patients with group II sphincter of Oddi dysfunction is associated with a low incidence of restenosis (4.7%). Repeat endoscopic sphincterotomy was found to be effective management in patients with papillary restenosis.

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Marc F. Catalano

Medical College of Wisconsin

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Walter J. Hogan

Medical College of Wisconsin

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Gk Johnson

Medical College of Wisconsin

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Dj Geenen

Medical College of Wisconsin

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Joseph E. Geenen

Medical College of Wisconsin

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G. Kenneth Johnson

Medical College of Wisconsin

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Rama P. Venu

Medical College of Wisconsin

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L. Jacob

Medical College of Wisconsin

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Lyndon V. Hernandez

Medical College of Wisconsin

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