Comparison of Surgically Resected Polypoid Lesions of the Gallbladder to their Pre-operative Ultrasound Characteristics

Background  Polypoid lesions of the gallbladder (PLG) have been a common finding on ultrasound examinations of the abdomen and are more prevalent since our use of equipment incorporating pulse shaping increased bandwidth, and enhanced phase use for image reconstruction began in 1996. Our study correlates the pre-operative ultrasonographic findings of these lesions to the surgically resected specimen with specific regard to identifying neoplastic polyps. Methods  A retrospective review was performed of 130 patients who had a pre-operative ultrasound of the gallbladder and subsequently underwent cholecystectomy between August 1996 and July 2007 at the Mayo Clinic Rochester. Results  Seventy-nine pseudopolyps (cholesterol polyps, inflammatory polyps, and adenomyomas) and 15 neoplastic polyps were identified on histopathologic analysis. However, 36 patients (27%) did not have a PLG upon histopathologic analysis. Thirty-one polyps had suspicious ultrasonographic characteristics for neoplastic changes. Twenty-nine were ≥10 mm, 12 had vascularity, and one demonstrated invasion. Of these, there were 23 pseudopolyps and six true polyps with neoplastic changes on final pathology (four dysplastic adenomas and two adenocarcinomas). Three asymptomatic polyps ≤10 mm (4%) in maximum diameter based on pre-operative ultrasound imaging (US) had neoplastic changes at pathology (two dysplastic adenomas and one adenocarcinoma). Several statistically significant risk factors were identified that increased the likelihood for malignancy in a PLG: history of primary sclerosing cholangitis (PSC), local invasion, vascularity, and ≥6 mm maximum diameter based on pre-operative US. Of PLGs ≤10 mm, 7.4% were neoplastic. Twenty-five patients were followed up with at least two serial ultrasound examinations. Of these, seven demonstrated polyp growth. None of these specimens demonstrated neoplastic changes. The positive predictive value (PPV) and negative predictive value (NPV) for ultrasound diagnosing neoplastic changes based on current criteria was 28.5% and 93.1%, respectively, with a false negative rate of 5.0%. Expanding the criteria to include cholecystectomy for PLGs ≥ 6 mm changes the positive predictive value and negative predictive value to 18.5% and 100%, respectively, with a false negative rate of 0%. Conclusion  Histopathologic analysis of polypoid lesions of the gallbladder continues to be the gold standard to identify malignancy. Ultrasound has been used extensively in the pre-operative management of these lesions, but modern ultrasound techniques are unable to differentiate between benign and malignant PLGs with any certainty. We recommend that strong consideration be given to surgical resection of PLGs ≥ 6 mm based on pre-operative US due to the significant risk of neoplasm. Additionally, PLGs in all patients with PSC, any patient in whom diligent long-term follow-up cannot be completed, and lesions that demonstrate growth, vascularity, invasion, or are symptomatic require cholecystectomy. Presented at SSAT at the DDW     

Canine ileal motor activity after a model of jejunoileal autotransplantation

OBJECTIVE: To determine mechanisms by which extrinsic innervation to the jejunoileum controls ileal motility. SUMMARY BACKGROUND DATA: Small bowel transplantation is complicated by diarrhea and delayed gastric emptying, possibly secondary to altered motility. Ileal motility after small bowel transplantation is poorly characterized. METHODS: Motor activity was recorded from four dogs during fasting and after feeding small (64 Kcal) or large (256 Kcal) meals. Short-chain fatty acids known to induce unique ileal motor patterns were administered into the distal ileum during fasting. Dogs were studied before and after jejunoileal denervation simulating autotransplantation. RESULTS: After jejunoileal denervation, the ileal migrating motor complex (MMC) persisted but was no longer temporally coordinated with duodenal MMCs. Spontaneous giant migrating contractions occurred more frequently after denervation and more commonly originated proximally in the jejunum, but the velocity of migration did not differ. In contrast, the incidence and characteristics of spontaneous discrete clustered contractions (DCCs) did not differ. Short-chain fatty acids reproducibly initiated giant migrating contractions and discrete clustered contractions in the distal ileum without differences before and after denervation. Large but not small meals inhibited the ileal MMC after denervation. CONCLUSIONS: Extrinsic innervation and/or intrinsic neural continuity with the duodenum and/or colon control temporal coordination of ileal motility with the duodenum and modulate postprandial inhibition of fasting motility and presence of giant migrating contractions. These changes in motility patterns may prove important in mediating enteric dysfunction after small bowel transplantation.     

Repair of a combined femoral pseudoaneurysm and arteriovenous fistula using a covered stent graft

Our purpose was to demonstrate clinical efficacy of covered stent use in the peripheral vasculature. A 68-year-old man was transferred from an outlying hospital for evaluation and treatment of a pulsatile mass in his right groin after cardiac catheterization. Imaging with duplex ultrasound and diagnostic arteriogram demonstrated a 6-cm pseudoaneurysm (PSA) of the right superficial femoral artery (SFA) and an arteriovenous fistula (AVF) of the SFA and the profunda vein. Using a covered stent extending from the proximal SFA across the origins of the AVF and PSA, complete exclusion was attained. Follow-up ultrasound at 6 weeks revealed a patent stent, no AVF, and thrombosis of the PSA. Endovascular treatment of peripheral lesions (AVF/PSA) in an elective to semi-elective setting offers patients a safe, less invasive treatment option to consider over traditional open surgery. Consequently, a formidable reduction in incision length, wound infection, and postoperative immobility can be expected.     

Contribution of intraoperative enteroscopy in the management of obscure gastrointestinal bleeding

Obscure gastrointestinal bleeding remains a significant diagnostic challenge. Our aims were (1) to determine the efficacy of intraoperative enteroscopy (IOE) in identifying lesions responsible for obscure gastrointestinal bleeding and (2) to determine the outcome of patients after treatment of these lesions. We retrospectively reviewed all patients who underwent IOE for obscure gastrointestinal bleeding from 1992 to 1998. Patients were divided into those with overt and those with occult gastrointestinal bleeding. Follow-up was complete in 67 patients (96%), with a median of 32 months (range 1 to 91 months). Seventy patients (52 overt and 18 occult) underwent IOE after extensive preoperative evaluation. Median duration of bleeding was 12 months, requiring a median of 14 blood transfusions. Risk factors for bleeding were identified in 46 patients (61 %). A lesion was identified and treated in 52 patients (74%)—39 in the overt group and 13 in the occult group. Lesions identified were vascular (54%), ulcerations (31%), tumors (11%), and small bowel diverticula (4%). Overall, 35 patients (52%) were found to have one or more lesions at IOE that were treated surgically and had no further bleeding. IOE, through a mid-small bowel enterotomy, has low morbidity and is effective in that it identified a treatable lesion in 74% of patients, which led to cure of bleeding in 52%. Presented at the Forty-First Annual Meeting of The Society for Surgery of the Alimentary Tract, San Diego, Calif., May 21–24, 2000, and published as an abstract in Gastroenterology 118(Suppl l):A1057, 2000.     

Red cell membrane stiffness in iron deficiency

The purpose of this study was to characterize red blood cell (RBC) deformability by iron deficiency. We measured RBC deformability to ektacytometry, a laser diffraction method for determining the elongation of suspended red cells subjected to shear stress. Isotonic deformability of RBC from iron-deficient human subjects was consistently and significantly lower than that of normal controls. In groups of rats with severe and moderate dietary iron deficiency, RBC deformability was also reduced in proportion to the severity of iron deficiency. At any given shear stress value, deformability of resealed RBC ghosts from both iron-deficient humans and rats was lower than that of control ghosts. However, increase of applied shear stress resulted in progressive increase in ghost deformation, indicating that ghost deformability was primarily limited by membrane stiffness rather than by reduced surface area-to-volume ratio. This was consistent with the finding that iron-deficient cells had a normal membrane surface area. In addition, the reduced mean corpuscular hemoglobin concentration (MCHC) and buoyant density of the iron-deficient rat cells indicated that a high hemoglobin concentration was not responsible for impaired whole cell deformability. Biochemical studies of rat RBC showed increased membrane lipid and protein crosslinking and reduced intracellular cation content, findings that are consistent with in vivo peroxidative damage. RBC from iron-deficient rats incubated in vitro with hydrogen peroxide showed increased generation of malonyldialdehyde, an end-product of lipid peroxidation, compared to control RBC. Taken together, these findings suggest that peroxidation could contribute in part to increased membrane stiffness in iron- deficient RBC. This reduced membrane deformability may in turn contribute to impaired red cell survival in iron deficiency.