Jon B. Morris

EUS compared with CT, magnetic resonance imaging, and angiography and the influence of biliary stenting on staging accuracy of ampullary neoplasms

BACKGROUND Computerized tomography (CT), magnetic resonance imaging (MRI), and transabdominal ultrasound frequently fail to detect ampullary lesions. Endoscopic ultrasound (EUS) is a sensitive modality for detecting and staging ampullary tumors. Accurate staging may be affected by biliary stenting, which is frequently performed in these patients with obstructive jaundice. The present study assessed the accuracy of ampullary tumor staging with multiple imaging modalities in patients with and those without endobiliary stents. METHODS Fifty consecutive patients with ampullary neoplasms from two endosonography centers were preoperatively staged by EUS plus CT (37 patients), MRI (13 patients), or angiography (10 patients) over a 3(1/2) year period. Twenty-five of the 50 patients had a transpapillary endobiliary stent present at the time of endosonographic examination. Accuracy of EUS, CT, MRI, and angiography was assessed with the TNM classification system and compared with surgical-pathologic staging. The influence of an endobiliary stent present at the time of EUS on staging accuracy of EUS was also evaluated. RESULTS EUS was more accurate than CT and MRI in the overall assessment of the T stage of ampullary neoplasms (EUS 78%, CT 24%, MRI 46%). No significant difference in N stage accuracy was noted between the three imaging modalities (EUS 68%, CT 59%, MRI 77%). EUS T stage accuracy was reduced from 84% to 72% in the presence of a transpapillary endobiliary stent. This was most prominent in the understaging of T2/T3 carcinomas. CONCLUSIONS EUS is superior to CT and MRI in assessing T stage but not N stage of ampullary lesions. The presence of an endobiliary stent at EUS may result in underestimating the need for a Whipple resection because of tumor understaging.

Protection of the small intestine from nonocclusive mesenteric ischemic injury due to cardiogenic shock

In a pericardial tamponade model of cardiogenic shock in pigs, we had previously shown that acute reductions in cardiac output produce severe mesenteric ischemia due to disproportionate splanchnic vasoconstriction. In this study, we extended the period of cardiogenic shock in order to investigate the pathogenesis of ischemic injury to the small intestinal wall. Four hours of tamponade produced sustained changes in splanchnic hemodynamics, similar to those observed in the prior short-term experiments. The resultant mesenteric ischemia caused necrotic lesions of the small intestine which were characteristic of those seen in nonocclusive mesenteric ischemia in human subjects. Prior alpha-adrenergic blockade failed to prevent either sustained mesenteric vasospasm or ischemic injury. In contrast, prior blockade of the renin-angiotensin axis, whether by nephrectomy or angiotensin-converting enzyme inhibition, blocked the splanchnic vasoconstriction, and thereby protected the small intestine from ischemic injury. The primary hemodynamic and pathologic features of this model of nonocclusive mesenteric ischemia appear to be mediated by the renin-angiotensin axis.

Role of surgery in antibiotic-induced pseudomembranous enterocolitis

With the increased use of prophylactic and broad-spectrum antibiotics, pseudomembranous colitis has emerged as a significant clinical problem. Management with specific anti-Clostridium difficile therapy (vancomycin or metronidazole) has reduced mortality to less than 2%. Nevertheless, the disease may progress to a fulminant toxic colitis or colonic perforation. Additionally, another subset of patients will present with a dramatic clinical picture, suggesting acute peritonitis, eventuating in unnecessary laparotomy. This report reviews both the medical and surgical literature during the past 15 years of patients treated for pseudomembranous colitis. Analysis of this clinical data has provided us with the opportunity to both define the role of surgery in this disorder and illustrate the necessity for a combined medical and surgical cooperative approach in the early management of this iatrogenic disease.

Internal medicine and general surgery residents' attitudes about the ACGME duty hours regulations: a multicenter study.

Purpose To assess internal medicine and general surgery residents’ attitudes about the effects of the Accreditation Council for Graduate Medical Education duty hours regulations on medical errors, quality of patient care, and residency experiences. Method In 2005, the authors surveyed 200 residents who trained both before and after duty hours reform at six residency programs (three internal medicine, three general surgery) at five academic medical centers in the United States. Residents’ attitudes about the effects of the duty hours regulations on the quality of patient care, residency education, and quality of life were measured using a survey instrument containing 19 Likert scale questions on a scale of 1 to 5. Survey responses were compared using the Student’s t-test. Results The response rate was 80% (159 residents). Residents reported that whereas fatigue-related errors decreased slightly, errors related to reduced continuity of care significantly increased. Additionally, duty hours regulations somewhat decreased opportunities for formal education, bedside learning, and procedures, but there was no consensus that graduates would be less well trained after duty hours reform. Residents, particularly surgical trainees, reported improvements in quality of life and reduced burnout. Conclusions Residents in medicine and surgery had similar opinions about the effects of duty hours reform, including improved quality of life. However, resident opinions suggest that reduced fatigue-related errors have been offset by errors related to decreased continuity of care and that the quality of the educational experience may have declined. Quantifying the degree to which regulating duty hours affected errors related to discontinuity of care should be a focus of future research.

Long term survival after pancreatic resection for pancreatic adenocarcinoma

OBJECTIVE:The aim of this study was to determine the long term survival of patients with pancreatic adenocarcinoma who underwent surgical resection and to assess the association of clinical, pathological, and treatment features with survival.METHODS:Between January, 1990, and December, 1998, 125 patients underwent a pancreaticoduodenal or partial pancreatic resection for pancreatic ductal adenocarcinoma at our institution. The records of these patients were reviewed for demographics, tumor characteristics including size, histological grade, margin status, lymph node status, surgical TNM staging, and postoperative adjuvant therapy. The primary outcome variable analyzed was survival.RESULTS:A total of 116 patients had complete follow-up and were included in the final analysis. The median survival after surgery was 16 months. The 1-, 3-, 5-, and 7-yr survival rates for all 116 patients were 60%, 23%, 19%, and 11%, respectively. The 1-, 3-, 5-, and 7-yr survival rates for patients who received adjuvant therapy were 69%, 28%, 23%, and 18% compared with 20% and 0% in patients who did not receive adjuvant therapy (p < 0.0001). The 1-, 3-, 5-, and 7-yr survival rates for patients with negative lymph nodes were 73%, 38%, 26%, and 22% compared with survival rates of 52%, 14%, 14%, and 9% in patients with positive lymph nodes (p = 0.01). In multivariate analyses, adjuvant therapy was the only feature found to be strongly associated with survival (hazards ratio = 0.26, 95% CI = 0.15–0.44).CONCLUSIONS:The overall 5- and 7-yr survival rates of 19% and 11% in our study further validate that surgical resection in patients with pancreatic adenocarcinoma can result in long term survival, particularly when performed in association with adjuvant chemoradiation.

Pathogenesis of nonocclusive ischemic colitis

The nonocclusive component of ischemic colitis in anesthetized pigs was mimicked using cardiogenic shock produced by pericardial tamponade. Increases in pericardial pressure produced decreases in arterial pressure (PA) and cardiac output (CO), with corresponding rises in total peripheral resistance (i.e., cardiogenic shock). This was associated with marked reductions in blood flow through the inferior mesenteric artery (IMA), due primarily to disproportionate increases in IMA vascular resistance. Levels of plasma renin activity correlated closely with these changes in mesenteric hemodynamics. Confirmed, total alpha adrenergic blockade with phenoxybenzamine failed to block this selective mesenteric vasoconstriction, while ablation of the renin-angio-tensin axis with captopril completely abolished it, thereby ameliorating the colonic ischemia. Central intravenous infusions of pathophysiologic levels of angiotensin II, without tamponade, mimicked the response to shock seen with tamponade alone. In an additional group of pigs, 4 hours of sustained shock (tamponade) followed by 2 hours of normotension (release of tamponade and resuscitation) produced lesions characteristic of ischemic colitis, including full-thickness mucosal ulceration. Such lesions were ameliorated significantly in pigs in which the renin-angiotensin system had been ablated by bilateral nephrectomy. Nonocclusive ischemic colitis appears to be mediated primarily by a remarkable sensitivity of the colonic vasculature to the renin-angiotensin axis.

Endosonography is superior to angiography in the preoperative assessment of vascular involvement among patients with pancreatic carcinoma.

Surgical exploration in patients with pancreatic carcinoma without adequate preoperative attempts to determine resectability results in resection in only a minority of patients. Besides distant metastases, involvement of the major vessels is the most important parameter for determining resectability in patients with pancreatic adenocarcinoma. Angiography has been an integral part of pancreatic cancer staging. Lately, endoscopic ultrasound (EUS) has emerged as a more accurate tool in the diagnosis and staging of pancreatic cancer. We hypothesize that EUS is more accurate than selective venous angiography (SVA) for assessing resectability of pancreatic adenocarcinoma based on preoperative evaluation of vascular involvement. Twenty-one patients who met the inclusion criteria were prospectively evaluated with both EUS and SVA before undergoing surgical exploration for attempted curative resection. Vascular involvement was determined by EUS and SVA using previously described criteria. The sensitivity, specificity, and overall accuracy of EUS and SVA in assessing vascular involvement were compared, using surgical exploration as the gold standard. Endoscopic ultrasound had a higher sensitivity than SVA for detecting vascular involvement (86% vs. 21%, respectively;p = 0.0018). The specificity and accuracy of EUS for detecting vascular involvement was 71% and 81%, respectively. In contrast, the specificity and accuracy of SVA for detecting vascular involvement was 71% and 38%, respectively. Endoscopic ultrasound is significantly more sensitive than angiography for detecting vascu lar involvement in patients with pancreatic adenocarcinoma and, thus, may improve patient selection for attempted curative resection.

Surgical jejunostomy in aspiration risk patients.

One hundred patients underwent laparotomy for independent jejunal feeding tube placement. Neurologic disease was present in 50%, and obtundation (28) and oropharyngeal dysmotility (25) were the most common indications for enteral feeding. The post-pyloric route was chosen because of aspiration risk in almost all (94%) patients. Postoperative (30-day) mortality rate was 21%, because of cardiopulmonary failure in most (18). One death resulted directly from aspiration of tube feeds. Two surgical complications required reoperation: one wound dehiscence and one small bowel obstruction. Four wound infections occurred. Two patients underwent reoperation after tube removal, and four tubes required fluoroscopically guided reinsertion for peritubular drainage (2), removal (1), and occlusion (1). Aspiration pneumonia was present in 18 patients preoperatively and in eight postoperatively. None of the patients with feeding-related pre-operative aspiration pneumonia (13) had a recurrence while fed by Jejunostomy. Three patients developed postoperative aspiration pneumonia before initiation of Jejunostomy feedings. Jejunostomy may be performed with low morbidity rate and substantial reduction of feeding-related aspiration pneumonia, and is the feeding route of choice in aspiration risk patients.

Perceptions of Graduating General Surgery Chief Residents: Are They Confident in Their Training?

BACKGROUND Debate exists within the surgical education community about whether 5 years is sufficient time to train a general surgeon, whether graduating chief residents are confident in their skills, why residents choose to do fellowships, and the scope of general surgery practice today. STUDY DESIGN In May 2013, a 16-question online survey was sent to every general surgery program director in the United States for dissemination to each graduating chief resident (CR). RESULTS Of the 297 surveys returned, 76% of CRs trained at university programs, 81% trained at 5-year programs, and 28% were going directly into general surgery practice. The 77% of CRs who had done >950 cases were significantly more comfortable than those who had done less (p < 0.0001). Only a few CRs were uncomfortable performing a laparoscopic colectomy (7%) or a colonoscopy (6%), and 80% were comfortable being on call at a Level I trauma center. Compared with other procedures, CRs were most uncomfortable with open common bile duct explorations (27%), pancreaticoduodenectomies (38%), hepatic lobectomies (48%), and esophagectomies (60%) (p < 0.00001). Of those going into fellowships, 67% said they truly had an interest in that specialty and only 7% said it was because they were not confident in their surgical skills. CONCLUSIONS Current graduates of general surgery residencies appear to be confident in their skills, including care of the trauma patient. Fellowships are being chosen primarily because of an interest in the subspecialty. General surgery residency no longer provides adequate training in esophageal or hepatopancreatobiliary surgery.

The utility of computed tomography in colonic diverticulitis.

Forty-one patients admitted to our hospital during an 18-month period with the clinical diagnosis of colonie diverticulitis were analyzed to evaluate the utility of computed tomography (CT). Abdominal pain and leukocytosis were the most common presenting manifestations, 75 and 66%, respectively. Just over one-half of the patients also demonstrated hematuria. Twenty patients required surgical intervention, most commonly for failure to improve despite medical management. Preoperative studies included 10 sigmoidoscopies, 30 plain abdominal roentgenograms, 20 barium enemas (BE), and 24 CT scans. Two CT scans were also obtained after operation for successful percutaneous drainage of intra-abdominal abscesses. Abdominal roentgenograms were most commonly obtained but least helpful, with only one third demonstrating any abnormality whatsoever. Sigmoidoscopy was least commonly performed but almost universally abnormal. Specificity was low, however, in that spasm with inability to advance the endoscope was the most common finding. Of the 20 barium enemas obtained, 60% had findings consistent with diverticulitis, most commonly localized perforation or fixed narrow segment. Sixty-three per cent of CT scans were abnormal. The most frequent findings were localized thickening of the colonie wall and increased density in the pericolic fat. Diverticular abscess, which may be inferred by other studies, was definitely diagnosed in one third of the patients with abnormal CT scans. CT also provided the ability to identify extracolonic intra-abdominal pathology. The study demonstrates that both barium enema and CT are effective in diagnosing diverticulitis, although CT can be performed without risk. CT played no therapeutic role before operation, although two patients benefited after operation by CT-guided drainage of intra-abdominal abscesses. The decision for surgery was most frequently dependent on clinical examination and never solely on the basis of either the barium enema or CT in this study. The major benefit of CT appears to be its ability to identify both gross and subtle changes indicative of diverticular disease and extracolonic pathology in a relatively noninvasive manner.