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Biomedical subjects

J M Marks

Publications and source records attributed to J M Marks.

At least 19 recordsLinked to original sources
PubMed2005

The economic impact of incorporating flexible endoscopy into a community general surgery practice.

BACKGROUND: Flexible endoscopy is a vital component of gastrointestinal surgery. It has and will replace many of the surgical procedures now commonly performed. Flexible endoscopy, unfortunately, is not an integral part of surgical residency training based on resident operative experience as reported by the Residency Review Committee. Moreover, general surgeons have deferred the practice of flexible endoscopy to the gastroenterologists because of concerns over turf battles and referral patterns. The purpose of this study was to assess the overall case load and the economic impact of flexible endoscopy on the practice of general surgery in a community hospital setting. METHODS: This retrospective review was performed over a 6-month period. The total cases and the total billings of inpatient and outpatient procedures for a group practice of five general surgeons in a community hospital were evaluated. The billings were the actual charges based on current procedural terminology (CPT) codes for these procedures using the Medicare fee schedule. RESULTS: Of the 2,159 procedures performed, 1,154 involved flexible endoscopy cases accounting for 54% of all cases (1,154 of 2,159) performed from February 1, 2003 to July 31, 2003. Flexible endocopy accounted for 43% of the total charges. A. total of 46 surgical procedures and 216 future endoscopies were generated from the flexible endoscopic procedures. Future endoscopic cases were for surveillance of colonic neoplasia and Barrett's esophagus. CONCLUSIONS: Flexible endoscopy contributed to a major portion of the caseload and revenue generated by the general surgery group studied. The overall impact of flexible endoscopy is even greater than reported because of the future endoscopic surveillance cases or surgical interventions generated on the basis of endoscopic findings.

Ambulatory Surgical Procedures↗
PubMed2001

Evaluation of endoscopic and laparoscopic training practices in surgical residency programs.

BACKGROUND: The ability to adequately train surgical residents in flexible and rigid endoscopy has become a difficult challenge for program directors. The American Board of Surgery requires residents to be familiar in these procedures but the methods for training have not been well defined nor formally outlined. The goals of this study were to evaluate resident experience in flexible endoscopy and laparoscopy and to investigate the specific methods used by surgical programs for the training of residents. METHODS: A survey was created by the authors and the Resident Education Committee of the Society of American Gastrointestinal Endoscopic Surgeons and was mailed to all program directors in general surgery in the United States based on the data base of the Association of Program Directors in Surgery (APDS). RESULTS: Ninety-six of 283 surveys were returned (33.9%). The surgeon played a greater role in flexible endoscopic training in 1998 as compared to 1988 (p=0.002). When analyzed by type of institution, community programs showed a similar trend but this was not seen in academic programs. Formal endoscopy rotations existed in 60% of programs but flexible endoscopy (5.2%) and laparoscopy (10.4%) fellowships were uncommon. No significant differences in the number of advanced laparoscopic procedures performed were found between academic and community programs. The presence of a laparoscopic fellow did not significantly decrease the number of cases per resident. CONCLUSION: According to our survey, surgery departments have a greater impact on flexible endoscopic training in 1998 than in 1988. This is likely due to the creation of formal endoscopy rotations and the hiring of fellowship trained endoscopic instructors. In addition, community programs have been able to provide adequate experience in both basic and advanced laparoscopic techniques as compared to academic programs. As with flexible endoscopy, however, formal laparoscopic rotations may be necessary to allow more intensive experience for each resident.

Academic Medical Centers↗
PubMed2001

A comparison of common bile duct pressures after botulinum toxin injection into the sphincter of Oddi versus biliary stenting in a canine model.

BACKGROUND: Botulinum toxin A (Botox) functionally paralyzes the sphincter of Oddi in both animals and humans, resulting in reduced pressures. No study, however, has specifically addressed common bile duct (CBD) pressures after Botox injection into the sphincter of Oddi with regard to treating biliary leaks and fistulae. The goals of this present study are to compare, versus biliary stenting, the change in CBD pressures after Botox injection into the sphincter of Oddi, as well as to evaluate the timing of onset and duration of these effects on sphincteric relaxation. METHODS: After midline laparotomy in 20 mongrel dogs, a pediatric umbilical catheter was inserted into the CBD via a small cholecystotomy and attached to a water-perfused pressure transducer. After baseline CBD pressure readings, a lateral duodenotomy was performed. A total of 100 units of Botox was injected with an endoscopic sclerotherapy needle into all four quadrants of the ampulla. The dogs were randomly divided into four groups to undergo repeat laparotomy at either postoperative day 1 (group I), postoperative day 3 (group II), postoperative day 7 (group III), or postoperative day 14 (group IV). At the time of second laparotomy, a pressure-sensing catheter was reinserted into the CBD and pressures recorded. Each dog then underwent transpapillary biliary stenting with a 7 Fr. x 5 cm Cotton-Leung biliary stent and CBD pressures were again recorded. RESULTS: CBD pressures were significantly lower as compared with baseline for all groups after Botox injection and after biliary stenting (P <0.001) In addition, no significant differences in the degree of CBD pressure reduction were identified between groups I through IV after Botox injection. The measured decrease in CBD pressure from baseline after Botox injection as compared with biliary stenting was significantly different for groups I and II (P <0.05) but not for groups III and IV. CONCLUSION: Botox injection into the sphincter of Oddi results in significant CBD pressure reduction within 24 hours and continues for 14 days. Also, after postoperative day 3, there is no significant difference in the reduction of CBD pressure from baseline between Botox injection and biliary stenting. Based on these findings, Botox injection into the sphincter of Oddi may be a beneficial alternative to biliary stenting for the treatment of biliary leaks and fistulae.

Animals↗
PubMed2000

Short-term endobiliary stenting results in chronic inflammation of the porcine extrahepatic biliary system.

This study reports the histologic changes seen in the biliary ductal system and pancreas as a result of endobiliary stenting. Ten mini pigs underwent endoscopic placement of suprapapillary endobiliary stents. The animals were killed and the liver, biliary tree, and pancreas were resected en bloc and prepared for histologic examination. Endobiliary stenting was found to result in significant chronic inflammation in the biliary system within 4 weeks of stent placement. These changes were present throughout the entire extrahepatic biliary ductal system and persisted throughout the 15-week study period. There was no significant acute inflammation in the biliary tree nor acute or chronic inflammation in the pancreatic duct. Further study is indicated to determine whether these changes will result in fibrosis and stricture.

Animals↗
PubMed1998

GABA receptor subunit mRNA expression in brain of conflict, yoked control and control rats.

Animal conflict models have been used for years as a preclinical screen for predicting anxiolytic therapeutic efficacy. Anxiolytics, including benzodiazepines, increase punished responding. This suggests that the punished behavior may be mediated by the GABA receptor. To evaluate this hypothesis, we performed in situ hybridization histochemistry studies of GABA receptor subunits (alpha1-alpha4) and synthetic enzymes glutamic acid decarboxylase (GAD65 and GAD67) in four groups of rats: conflict (punishment), yoked controls (rats shocked without conflict training history), fixed interval only controls (rats that worked for food but were not shocked) and untreated controls. With conflict behavioral training, bilateral reduction of mRNA for the GABAA alpha1 subunit was seen relative to controls in the cortex, thalamus and hippocampus. In contrast, alteration of alpha2 mRNA levels appeared only in the yoked control group, with increased levels seen in the thalamus and cortex and decreased levels in the hippocampus. There were no differences in the alpha2 mRNA level between the control and the conflict behavioral trained animals. Further, no significant differences were found between groups in the mRNA levels for the alpha3 subunit, alpha4 subunit, GAD65, and GAD67. These results suggest that the behaviors related to conflict and uncontrollable aversive stimuli (yoked control group) are accompanied and perhaps mediated by selective changes in the GABAA alpha1 or alpha2 subunits, respectively. These findings highlight the potential usefulness of the conflict model as a means of elucidating the biological underpinnings of anxiety disorder. Published by Elsevier Science B.V. All rights reserved.

Animals↗
PubMed1998

Biliary stenting is more effective than sphincterotomy in the resolution of biliary leaks.

BACKGROUND: Biliary fistulae may occur following surgical injury, abdominal trauma, or inadequate closure of a cystic duct stump. These leaks are most often managed by drainage of the associate biloma and either endoscopic sphincterotomy or placement of a biliary endoprosthesis to decrease the pressure gradient between the bile duct and the duodenum created by the muscular contraction of the ampullary sphincter. In a previous study, we demonstrated a statistically significant reduction in ductal pressures following stent placement as compared to sphincterotomy. The goal of this present study was to determine if reduction in ductal pressures correlates clinically with the resolution of biliary leaks in an animal model. METHODS: Fourteen mongrel dogs underwent laparotomy, cholecystectomy without closure of the cystic stump, and a lateral duodenotomy to identify the major papilla. The dogs were then randomized into three groups. Group I (n = 5) was a control group undergoing closure of the duodenotomy only. Group II (n = 4) underwent sphincterotomy. Group III (n = 5) underwent placement of a 7 Fr x 5 cm biliary endoprosthesis prior to duodenotomy closure. A drain was placed adjacent to the cystic duct stump in all groups. Drain output was recorded daily. The biliary leak was considered resolved when the output was < 10 cc/day. Regardless of suspected fistula closure, the drains were not removed until 2 weeks postprocedure. Necropsy was performed to identify undrained intraperitoneal bile. Statistical analysis was performed using Student's paired t test. RESULTS: All dogs had bile leaks identified on postoperative day 1. The number of days required for resolution of bile leak in group I (mean +/- SEM) was 7.60 +/- 0.87 days, as compared to 6.75 +/- 0.80 days for group II and 2.60 +/- 0.24 days for group III. There was no significant difference in the duration of bile leak between groups I and II (p = 0.445). Group III, however, had a significant reduction in the duration of biliary fistulae as compared to both groups I and II (p < 0.005). At autopsy, persistent bilomas were identified in 80% of group I, 25% of group II, and 0% of group III. None of the dogs showed evidence of dehisence of the duodenotomy closure site as a source of bile leak. CONCLUSION: Biliary stenting significantly reduces the time to resolution of cystic duct leaks as compared to sphincterotomy in a canine model. The results obtained in this study support the use of biliary endoprostheses in the management of biliary leaks and fistulae.

Animals↗
PubMed1998

Pretreatment with allopurinol diminishes pancreatography-induced pancreatitis in a canine model.

BACKGROUND: The role of oxygen-derived free radicals in the pathogenesis of pancreatitis has been supported by data from previous studies using animal models. This study was conducted to determine whether prophylaxis with the xanthine oxidase inhibitor allopurinol would decrease the incidence and severity of pancreatography-induced pancreatitis in a canine model. METHODS: Thirty-two dogs were randomized to receive either placebo or oral allopurinol 1 hour before the procedure. A laparotomy and duodenotomy were performed and a pancreatogram was obtained. Postoperatively, pancreatic enzymes were drawn for 5 days. The animals were then euthanized, and the pancreas was weighed and evaluated histologically. RESULTS: The histologic incidence of pancreatitis was significantly reduced in the allopurinol pretreatment group (6.7%) as compared with the placebo group (41.2%, p < 0.01). A significant decrease in postoperative serum amylase levels among dogs pretreated with allopurinol was also noted. A similar trend was observed in lipase levels. The pancreas weight index was decreased in the allopurinol pretreatment group as well (control = 0.00246 vs. allopurinol = 0.00195, p < 0.02). CONCLUSIONS: Pretreatment with oral allopurinol decreases the incidence of pancreatography-induced pancreatitis. These results support the role of xanthine oxidase inhibitors in the prevention of endoscopic retrograde cholangiopancreatography-induced pancreatitis.

Allopurinol↗
PubMed1998

Percutaneous endoscopic gastrostomy.

Accessing the stomach via a gastrostomy is the preferred method for providing enteral nutritional support when supplementation is required for more than three or four weeks. Since its introduction in the early 1980s, percutaneous endoscopic gastrostomy has become the most popular method for creating a gastrostomy. It is a quick and cost-effective method and has supplanted open gastrostomy for the establishment of a gastrocutaneous fistula to provide access to the stomach for numerous indications. It is associated, however, with serious and potentially lethal complications which must be completely understood by the endoscopist. In addition, patient selection and thorough attention to details are paramount to the performance of a safe percutaneous endoscopic gastrostomy.

Cost-Benefit Analysis↗
PubMed1997

Comparison of bile duct pressures following sphincterotomy and endobiliary stenting in a canine model.

BACKGROUND: Cystic duct (CD) leaks following laparoscopic cholecystectomy may be diagnosed and managed with ERCP. Treatment options include endoscopic sphincterotomy (ES) and/or endobiliary stenting (Stent). This study was undertaken to determine if ES or Stent is more effective in lowering bile duct pressures by disrupting the pressure gradient created by the sphincter of Oddi and therefore more beneficial in the management of CD. METHODS: Mongrel dogs underwent midline laparotomy and antegrade cannulation of the common bile duct (CBD) with an umbilical artery catheter. Baseline CBD pressures were measured following duodenotomy; 5 Fr and 7 Fr stents measuring 2.5 cm, 4.5 cm, and 7 cm were inserted retrograde into the CBD. CBD pressure was measured after each stent insertion. A 1-cm sphincterotomy was the performed using a double channel papillotome. RESULTS: Insertion of both 5 Fr and 7 Fr stents significantly lowered CBD pressure as compared to sphincterotomy alone, p < 0.05. There was no significant difference in the reduction in CBD pressure following the insertion of either the 5 Fr or 7 Fr stents of varying lengths. Sphincterotomy alone did not significantly decrease CBD pressure as compared to baseline pressure. The insertion of a stent following sphincterotomy also caused a significant decrease in CBD pressure as compared to sphincterotomy alone, p = 0.034. CONCLUSION: Stent placement or ES with Stent placement significantly reduced CBD pressure as compared to ES alone. Stent diameter and length were not significant variables in this study. These results support the use of Stent or ES with Stent rather than ES alone in the management of CD leaks.

Animals↗
PubMed1997

Cost analysis of diagnostic laparoscopy vs laparotomy in the evaluation of penetrating abdominal trauma.

BACKGROUND: Diagnostic laparoscopy for the evaluation of injuries in patients with penetrating abdominal trauma has been shown to decrease the morbidity and mortality associated with mandatory laparotomy. The overall impact on patient care and hospital costs has not been thoroughly investigated. The goal of this study was to determine the economic impact of laparoscopy as a diagnostic tool in the management of patients following penetrating trauma to the abdomen or flank. METHODS: Retrospective chart review of all hemodynamically stable patients with penetrating trauma to the abdomen or flank, but without other injuries requiring emergent intervention, admitted to a level I trauma center between January 1, 1992, and September 30, 1994. Those patients who underwent either laparoscopy (DL) or laparotomy (NL) or both (CONV) and who had no intraabdominal organ injuries requiring surgical therapeutic intervention were included in the study. Age, operative time, operative findings, length of hospitalization, Injury Severity Score (ISS), variable costs, and total costs were recorded for each patient. RESULTS: Fourteen patients underwent negative/nontherapeutic laparoscopy (DL), 19 patients underwent negative/nontherapeutic laparotomy (NL), and four patients underwent both laparoscopy and laparotomy, a conversion procedure (CONV). There was no significant difference in age, operative times, or ISS between the DL and NL groups. Mean ISS of CONV patients was significantly greater than that of DL patients, 5.75 +/- 1.97 vs 2.43 +/- 0.63 (p < 0.05). Mean operative time for CONV patients was also significantly greater than both DL and NL patients, 106.5 +/- 17.00 min vs 66.1 +/- 6.55 and 47. 3 +/- 7.50 min, respectively (p < 0.05). The mean length of stay was significantly shorter in the DL group as compared to the NL or CONV groups, 1.43 +/- 0.20 vs 4.26 +/- 0.31 and 5.0 +/- 0.82 (p < 0.0001). The variable costs for the DL group were significantly lower than those incurred by patients in the NL and CONV groups, $2,917 +/- 175 vs $3,384 +/- 102 and $3,774 +/- 286, (p < 0.05). Variable costs were not significantly different between the NL and CONV groups. Total costs were also significantly lower in the DL group when compared to NL and CONV, $5,427 +/- 394 vs $7,026 +/- 251 and $7,855 +/- 750 (p < 0.005), but again, they were not statistically different between the NL and CONV groups. The overall total costs for laparoscopy, including the costs incurred by conversion patients, was significantly less than the total costs for laparotomy patients, $5,664 +/- 394 vs $7,028.47 +/- 250 (p < 0.005). This resulted in an overall savings of $1,059.44 per laparoscopy performed. The overall negative/nontherapeutic laparotomy rate during this study was 19.1%, which was significantly lower than the negative or nontherapeutic exploration rate during the time period prior to the use of laparoscopy (p < 0.01, z = 2.550). CONCLUSION: Variable and total costs and length of stay were significantly lower in our population of patients who underwent DL as compared to NL. The rate of negative or nontherapeutic laparotomy was also significantly reduced when compared to the rate identified during the era prior to the use of laparoscopy. Laparoscopy resulted in an overall savings of $1,059 per laparoscopy performed when compared to laparotomy.

Abdominal Injuries↗
PubMed1996

Management of common bile duct stones.

Management of common bile duct stones has changed rapidly as new developments in surgical and endoscopic equipment have become available. Prior to advanced laparoscopic surgical techniques and endoscopic sphincterotomy, common bile duct stones required open surgery, choledochotomy, and manual removal. New alternatives in the management of choledocholithiasis must be understood to allow for comprehensive management of common bile duct stones. Endoscopic and surgical techniques can also be combined for excellent results utilizing minimally invasive techniques. The appropriate choice of therapy will depend on the experience and the resources available.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1995

Access routes for enteral nutrition.

Comprehensive management of patients includes a thorough evaluation of nutritional requirements. The risks and the benefits of enteral and parenteral supplementations have been heavily investigated. Recent literature supports use of the gastrointestinal tract, when functioning, as the preferred route for supplemental nutrition. There are multiple access routes available to clinicians to provide enteral nutrition, including feeding tubes, which can be placed transnasally, percutaneously, or surgically. These various techniques have individual indications, contraindications, and complications associated with the procedures. They also have varying levels of invasiveness and overall durability. We discuss the different access routes available for enteral feeding, as well as the process for selecting the most appropriate route.

Enteral Nutrition↗