Tissue distribution and acute toxicity of silver after single intravenous administration in mice: nano-specific and size-dependent effects

BACKGROUND

Silver nanoparticles (AgNPs) are an important class of nanomaterials used as antimicrobial agents for a wide range of medical and industrial applications. However toxicity of AgNPs and impact of their physicochemical characteristics in in vivo models still need to be comprehensively characterized. The aim of this study was to investigate the effect of size and coating on tissue distribution and toxicity of AgNPs after intravenous administration in mice, and compare the results with those obtained after silver acetate administration.

METHODS

Male CD-1(ICR) mice were intravenously injected with AgNPs of different sizes (10 nm, 40 nm, 100 nm), citrate-or polyvinylpyrrolidone-coated, at a single dose of 10 mg/kg bw. An equivalent dose of silver ions was administered as silver acetate. Mice were euthanized 24 h after the treatment, and silver quantification by ICP-MS and histopathology were performed on spleen, liver, lungs, kidneys, brain, and blood.

RESULTS

For all particle sizes, regardless of their coating, the highest silver concentrations were found in the spleen and liver, followed by lung, kidney, and brain. Silver concentrations were significantly higher in the spleen, lung, kidney, brain, and blood of mice treated with 10 nm AgNPs than those treated with larger particles. Relevant toxic effects (midzonal hepatocellular necrosis, gall bladder hemorrhage) were found in mice treated with 10 nm AgNPs, while in mice treated with 40 nm and 100 nm AgNPs lesions were milder or negligible, respectively. In mice treated with silver acetate, silver concentrations were significantly lower in the spleen and lung, and higher in the kidney than in mice treated with 10 nm AgNPs, and a different target organ of toxicity was identified (kidney).

CONCLUSIONS

Administration of the smallest (10 nm) nanoparticles resulted in enhanced silver tissue distribution and overt hepatobiliary toxicity compared to larger ones (40 and 100 nm), while coating had no relevant impact. Distinct patterns of tissue distribution and toxicity were observed after silver acetate administration. It is concluded that if AgNPs become systemically available, they behave differently from ionic silver, exerting distinct and size-dependent effects, strictly related to the nanoparticulate form.

Outpatient laparoscopic laser cholecystectomy

Laparoscopic laser cholecystectomy has been performed clinically in the United States since 1988. After refinement of the technique, the procedure was offered on an outpatient basis. Eighty-three patients underwent laparoscopic laser cholecystectomy during the study period. Thirty-seven (45%) had the procedure as an outpatient. Younger patients were more suited for the outpatient procedure and those without previous surgery were more likely to have the procedure done as an outpatient. Weight, operating time, and gallbladder pathology were similar, although patients with acute inflammation of the gallbladder were more likely to require hospitalization. The primary reason for patient admission was patient preference.

Polypoid lesions of the gallbladder

BACKGROUND

Polypoid lesions of the gallbladder encompass a wide variety of pathology. Although most of these lesions are benign, some early carcinomas of the gallbladder do present as polypoid lesions. Problems remain in selecting patients with polypoid lesions of the gallbladder for surgery, the operative approach, and the method of follow-up of those deemed not needing surgery.

DATA SOURCES

This review was done by Medline search of the English literature by the keywords "polypoid lesions of gallbladder," "gallbladder polyps," "carcinoma of gallbladder," and "benign tumors of gallbladder."

CONCLUSIONS

Most small polypoid lesions of the gallbladder are benign and remain static for years. Three- to six-monthly ultrasonography examination is warranted in the initial follow-up period but it is probably unnecessary after 1 or 2 years. Age more than 50 years and size of polyp more than 1 cm are the two most important factors predicting malignancy in polypoid lesions of the gallbladder. Other risk factors include concurrent gallstones, solitary polyp, and symptomatic polyp. Laparoscopic cholecystectomy is the treatment of choice unless the suspicion of malignancy is high, in which case it is advisable to have open exploration, intraoperative frozen section, and preparation for extended resection.

Diagnosis and treatment of gallbladder perforation

AIM: To present our clinical experience with gallbladder perforation cases.

METHODS: Records of 332 patients who received medical and/or surgical treatment with the diagnosis of acute cholecystitis in our clinic between 1997 and 2006 were reviewed retrospectively. Sixteen (4.8%) of those patients had gallbladder perforation. The parameters including age, gender, time from the onset of symptoms to the time of surgery, diagnostic procedures, surgical treatment, morbidity, and mortality were evaluated.

RESULTS: Seven patients had typeIgallbladder perforation, 7 type II gallbladder perforation, and 2 type III gallbladder perforation according to Niemeier’s classification. The patients underwent surgery after administration of intravenous electrolyte solutions, and were treated with analgesics and antibiotics within the first 36 h (mean 9 h) after admission. Two patients died of sepsis and multiple organ failure in the early postoperative period. Subhepatic abscess, pelvic abscess, pneumonia, pancreatitis, and acute renal failure were found in 6 patients.

CONCLUSION: Early diagnosis and emergency surgical treatment of gallbladder perforation are of crucial importance. Upper abdominal computerized tomography for acute cholecystitis patients may contribute to the preoperative diagnosis of gallbladder perforation.

Pathobiology of opisthorchiasis: an update

Opisthorchis viverrini infection is associated with several hepatobiliary diseases including cholangitis, obstructive jaundice, hepatomegaly, cholecystitis and cholelithiasis. Pathological consequences of O. viverrini infection occur mainly in the liver, extrahepatic bile ducts, gall bladder and kidney. These pathologies have been described in both humans and experimental animals. Moreover, both experimental and epidemiological evidence strongly implicate the liver fluke infection in the etiology of cholangiocarcinoma--the bile duct cancer. This review summarizes the pathology of opisthorchiasis from literature mainly published between 1970 and the present time and, particularly, emphasizes on current concept in pathogenesis of the disease. The theme is to highlight the new era of pathogenetic study of opisthorchiasis especially on host-parasite interaction and host immune/inflammatory responses leading to tissue damage.

Incidental gallbladder cancer by the AFC-GBC-2009 Study Group

BACKGROUND

Incidental gallbladder cancer (GBC) is frequently discovered on the specimen when cholecystectomy for a benign disease is performed. The objective of the present study was to assess the management of incidental GBC patients in a French registry.

METHODS

Data on patients with GBC treated between 1998 and 2008 were retrospectively collated in a French, multicenter database.

RESULTS

The registry contained 218 patients with incidental GBC (67 men and 151 women; median age = 64 years; age range = 31-88). One hundred forty-eight (68%) patients underwent re-resection after a median time interval of 48 days (range = 2-245). The most common complete procedure (66% of cases) was 4b + 5 segmentectomy with lymphadenectomy but not bile duct resection. Port-site excision was performed in 54 patients. The mortality and morbidity rates were 3 and 37%, respectively. Resection of the common bile duct (43%) increased postoperative complications (60 vs. 23%, p = 0.0001). Local residual tumor was found in 83 (56%) patients; it was significantly correlated with the T stage and influenced long-term survival. R0 was obtained in 143 (97%) patients and port-site invasion was histologically confirmed in one patient (1.8%). After a median follow-up period of 34 months, the 1-, 3-, and 5-year survival rates for the 148 patients with re-resection were 76, 54, and 41%, respectively. Re-resection significantly increased survival in patients with T2 (p = 0.0001) and T3 (p = 0.04) disease. Resection of the common bile duct increased neither R0 resection nor overall survival (p = 0.06).

CONCLUSION

This study validates the concept of re-resection in T2 and T3 GBC. Bile duct resection increases postoperative morbidity but does not improve survival. There is currently a modification in the surgical management of incidental GBC, with minor liver resection and no common bile duct resection.

Propensity of ectopic liver to hepatocarcinogenesis: case reports and a review of the literature

Two patients with ectopic liver are described. In one patient, a small ectopic liver attached to the gastric serosa developed hepatocellular carcinoma (HCC). The preoperative diagnosis was an alpha-fetoprotein (AFP)-producing carcinoma and a malignant ulcer of the stomach. Total gastrectomy and esophago-jejunostomy were performed. The tumor that measured 4 x 2 x 2 cm contained an AFP-producing HCC and normal liver tissue. In another patient who had alcoholic cirrhosis, ectopic liver on the serosa of the gallbladder was found to have the same histological changes as the mother liver. A survey of the literature disclosed more than 20 cases in which HCC developed outside the liver; the liver did not have HCC. By contrast, there was only one report on HCC occurring in the liver in the presence of a noncancerous, relatively large accessory liver lobe. Because ectopic liver does not have a complete vascular and ductal system as a normal liver, it is perhaps functionally handicapped and more prone to hepatocarcinogenesis.

Hepatobiliary fibropolycystic diseases. A clinical and histological review of 51 patients

The clinical, radiological and hepatic histological features of 51 patients with hepatobiliary fibropolycystic disease were reviewed. Many of the patients had more than one of the diseases; the combination of both congenital hepatic fibrosis (CHF) and Caroli's disease was most striking. Twelve patients with CHF (50% male) presented at 6 +/- 2 years of age (mean +/- SEM) with hepatosplenomegaly or variceal bleeding. Their main problems were recurrent variceal bleeds and renal disease. Polycystic kidneys and renal stones were present in 79% and chronic renal failure in 30%. Six of the 8 patients with Caroli's disease were male (75%) and presented later (aged 37 +/- 8 years) with hepatomegaly or cholangitis. Recurrent cholangitis developed in most (7/8) and 2 had polycystic kidneys. Twelve patients had a combination of CHF and Caroli's disease presenting with hepatosplenomegaly, bleeding or cholangitis. As in Caroli's disease, most (83%) were male, but the age of presentation (15 +/- 4 years), and the incidence of polycystic kidneys (42%) and renal failure (8%) was intermediate between CHF and Caroli's disease. In these patients, bleeds always predated cholangitis. Histologically, acute cholangitis was superimposed on the changes of CHF. Adult polycystic liver disease (10 patients) presented later (43 +/- 3 years) in females (90%) with pain, a mass or incidentally; polycystic kidneys were present in 33%. Microhamartomas (10 patients), which were usually incidental findings, were diagnosed latest (50 +/- 6 years). Three choledochal cysts were seen. The hazard of cancer in these diseases was reflected by 2 bile duct cancers and 1 pancreatic cancer (incidence 6%). This study has confirmed that hepatobiliary fibropolycystic diseases form part of a family and are often associated together. However, the diseases are of greatly differing severity and the prognosis in an individual patient is determined by the fibropolycystic diseases present.

Evidence that MIG-6 is a tumor-suppressor gene

Mitogen-inducible gene 6 (MIG-6) is located in human chromosome 1p36, a locus frequently associated with human lung cancer. MIG-6 is a negative regulator of epidermal growth factor (EGF) signaling, and we show that Mig-6 - like EGF - is induced by hepatocyte growth factor/scatter factor (HGF/SF) in human lung cancer cell lines. Frequently, the receptors for both factors, EGFR and Met, are expressed in same lung cancer cell line, and MIG-6 is induced by both factors in a mitogen-activated protein kinase-dependent fashion. However, not all tumor lines express MIG-6 in response to either EGF or HGF/SF. In these cases, we find missense and nonsense mutations in the MIG-6 coding region, as well as evidence for MIG-6 transcriptional silencing. Moreover, germline disruption of Mig-6 in mice leads to the development of animals with epithelial hyperplasia, adenoma, and adenocarcinoma in organs like the lung, gallbladder, and bile duct. These data suggests that MIG-6 is a tumor-suppressor gene and is therefore a candidate gene for the frequent 1p36 genetic alterations found in lung cancer.

Xanthogranulomatous cholecystitis

(Fibro) xanthogranulomatous cholecystitis is an uncommon lesion which may form a tumor-like mass in inflamed gallbladders. A few cases have been mistaken for neoplasms. In a review of 40 cases there were 26 associated with gallstones and nine with tumors of the biliary tract, six of which also had stones. Grossly the lesions are usually soft, are yellow to brown, and measure up to 2.5 cm. Microscopically, there are varying amounts of inflammation, xanthoma-like foam cells, and scarring. The lesions appear to result from ruptured Rokitansky-Aschoff sinuses with intramural extravasation of bile and subsequent xanthogranulomatous reaction.

From the archives of the AFIP. Benign tumors and tumorlike lesions of the gallbladder and extrahepatic bile ducts: radiologic-pathologic correlation. Armed Forces Institute of Pathology

A diverse spectrum of benign tumors and tumorlike lesions arises from the gallbladder and bile ducts, and despite their diversity, these lesions share common embryologic origins and histologic characteristics. Although these lesions are relatively uncommon, their importance lies in their ability to mimic malignant lesions in these locations. Benign neoplasms are derived from the epithelial and nonepithelial structures that compose the normal gallbladder and bile ducts. The epithelium gives rise to adenomas, cystadenomas, and the unusual condition of biliary papillomatosis. Granular cell tumors, neurofibromas, ganglioneuromas, paragangliomas, and leiomyomas are examples of benign tumors that may originate from nonepithelial structures. Tumorlike lesions are more commonly found in the gallbladder and include xanthogranulomatous cholecystitis, adenomyomatous hyperplasia, cholesterol polyps, and heterotopias. In the clinical setting of a patient with nonspecific abdominal complaints or symptoms of biliary obstruction, the discovery of a gallbladder or bile duct polyp or mass, gallbladder wall thickening, or biliary stricture is most often indicative of malignancy. However, the differential diagnosis should include benign tumors and tumorlike lesions. The preoperative determination of a benign lesion may significantly alter therapy and patient prognosis.

Gallbladder disease in Shetland Sheepdogs: 38 cases (1995-2005)

OBJECTIVE

To determine risk, clinical features, and treatment responses for gallbladder disorders in Shetland Sheepdogs.

DESIGN

Retrospective case-control study.

ANIMALS

38 Shetland Sheepdogs with gallbladder disease.

PROCEDURES

Medical records were reviewed for signalment, history, physical findings, laboratory results, imaging features, coexistent illnesses, histologic findings, treatments, and survival rates.

RESULTS

Mature dogs with gastrointestinal signs were predisposed (odds ratio, 7.2) to gallbladder disorders. Gallbladder mucocele was confirmed in 25 dogs. Concurrent problems included pancreatitis, hyperlipidemia, corticosteroid excess, hypothyroidism, protein-losing nephropathy, diabetes mellitus, cholelithiasis, and gallbladder dysmotility. Mortality rate was 68% with and 32% without bile peritonitis. Nonsurvivors had high WBC and neutrophil count and low potassium concentration. Although preprandial hypercholesterolemia, hypertriglyceridemia, and high serum liver enzyme activities were common, gallbladder disease was serendipitously discovered in 11 of 38 dogs. Histologic examination (n=20 dogs) revealed gallbladder cystic mucosal hyperplasia in 20 dogs, cholecystitis in 16, periportal hepatitis in 9, and vacuolar hepatopathy in 7. Surgery included cholecystectomy (n=17) and cholecystoenterostomy (4). In 1 hyperlipidemic dog without clinical signs, gallbladder mucocele resolved 6 months after beginning use of a fat-restricted diet and ursodeoxycholic acid.

CONCLUSIONS AND CLINICAL RELEVANCE

Shetland Sheepdogs are predisposed to gallbladder disorders, with mucoceles and concurrent dyslipidemia or dysmotility in many affected dogs. Most dogs were without clinical signs during mucocele development. Low survival rate after cholecystectomy in clinically affected dogs suggested that preemptive surgical interventions may be a more appropriate treatment strategy.

Localized vasculitis of the gastrointestinal tract

We studied the clinical and pathologic findings of 63 patients with localized vasculitis of the gastrointestinal tract, including 35 partial bowel resections, 14 cholecystectomies, five partial pancreatectomies, six appendectomies, one omentectomy, one gastrectomy, and one esophagectomy. Vasculitis was classified histologically as polyarteritis (n = 33), phlebitis (n = 12), Churg-Strauss angiitis (n = 8), small-vessel vasculitis (n = 6), Buerger's disease (n = 2), and giant-cell arteritis (n = 1). Nineteen of 33 cases of polyarteritis affected the small bowel or gallbladder, and nine patients with polyarteritis had elevated serum antinuclear antibodies or rheumatoid factor. Eight of 12 cases of phlebitis affected the right colon; there were giant cells in four of these 12 cases, a history of medication use in seven of eight cases, and no evidence of serum autoantibodies. Short-term follow-up (mean, 5 years) demonstrated that systemic disease developed in six of 23 patients with polyarteritis (four of whom had elevated serum rheumatoid factor or antinuclear antibodies), the patient with giant-cell arteritis, and one of two patients with Buerger's disease. Systemic vasculitis did not develop in patients with other types of vasculitis. We conclude that patients with gastrointestinal phlebitis, polyarteritis without serum autoantibodies, and small-vessel vasculitis have a low short-term risk for the development of systemic disease.

Hepatobiliary disease in cystic fibrosis: a survey of current issues and concepts

The incidence of hepatobiliary complications of cystic fibrosis (CF) has been increasing in parallel with the rate of survival. Detection of hepatic involvement remains a problem, as liver function tests, serum bile acid determinations, and ultrasonography do not permit an early diagnosis. The pathogenesis of cholelithiasis has been elucidated in the past few years. However, the mechanism leading to the pathognomonic CF lesion, focal biliary cirrhosis, is still unknown. There are indications that mucus plugging may be the ancestral lesion and the triggering factor. The possibility that correction of the abnormalities of bile acid metabolism could slow the progress or prevent CF cirrhosis is discussed in light of recent experimental data.

Surgical management of gallbladder mucoceles in dogs: 22 cases (1999-2003)

OBJECTIVES

To describe preoperative, surgical, and postoperative findings and determine prognostic indicators and treatment recommendations in dogs treated surgically for gallbladder mucocele.

DESIGN

Retrospective study.

ANIMALS

22 client-owned dogs.

PROCEDURES

Medical records of dogs with gallbladder mucoceles that were treated surgically were reviewed. History, clinical signs, results of selected clinicopathologic analyses and abdominal ultrasonography, surgical procedure performed, results of histologic examination of a liver biopsy specimen, and survival time were recorded. Follow-up information was obtained via telephone interview with owners and referring veterinarians.

RESULTS

Dogs were 7 to 15 years of age and had non-specific clinical signs (vomiting, anorexia, and lethargy). Physical examination findings included icterus, signs of depression, and signs of discomfort on palpation of the abdomen. Sixteen dogs had a definitive diagnosis and 6 dogs were strongly suspected of having a gallbladder mucocele on the basis of results of abdominal ultrasonography. Fifteen dogs survived after surgery; 3 of these dogs had bile-induced peritonitis, and 4 had pancreatitis. One dog was euthanatized as a result of severe pancreatitis, and 1 was euthanatized because of acute renal failure; 5 dogs died as a result of pancreatitis, cholecystitis, or bile-induced peritonitis. Hepatic abnormalities were detected histologically in all dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

No predictors of survival were identified. No associations between outcome of surgical treatment (survival vs nonsurvival) and preoperative findings, biliary rupture, surgical procedure performed, results of histologic examination of the liver, or development of pancreatitis were found. Cholecystoduodenostomy and cholecystectomy appear to be acceptable treatments for gallbladder mucocele.

Sonography of adenomyomatosis of the gallbladder: radiologic-pathologic correlation

Sonograms of six patients with adenomyomatosis of the gallbladder were reviewed and correlated with oral cholecystographic and pathologic findings. The gallbladder was visualized in four of the six patients by oral cholecystography, which also revealed intramural diverticula. Five of the six patients showed sonographic evidence of diffuse or segmental thickening of the gallbladder wall and intramural diverticula, seen as anechoic or echogenic foci within the wall. Intramural diverticula containing bile appeared as anechoic spaces; those containing biliary sludge or gallstones appeared as echogenic foci with or without acoustic shadows or reverberation artifacts. There was good correlation between sonographic and pathologic findings in three patients. The authors conclude that adenomyomatosis of the gallbladder should be suspected when (a) there is diffuse or segmental thickening of the gallbladder wall and (b) intramural diverticula are seen as anechoic or echogenic foci with or without associated acoustic shadows or reverberation artifacts.

Gallbladder Perforation: Risk Factors and Outcome

BACKGROUND

Gallbladder perforation is difficult to diagnose and is associated with significant morbidity. This study investigates factors affecting outcome in patients with gallbladder perforation over two decades.

MATERIALS AND METHODS

From 1982 to 2002 data from patients undergoing cholecystectomy at one institution were prospectively collected. Patients treated for gallbladder perforation and gangrenous cholecystitis were identified and outcomes were compared. The chi(2) test, Student's t-test, and Mann-Whitney rank sum test were used for statistical analysis.

RESULTS

Two hundred eight of 11,360 patients who underwent cholecystectomy were diagnosed with gangrenous cholecystitis and 30 were diagnosed with gallbladder perforation. The perforation was contained in 9 and free in 21 patients. The diagnosis of gallbladder perforation was made preoperatively in 3% of patients. Men outnumbered women and Hispanics outnumbered Caucasians. Compared to patients with gangrenous cholecystitis, patients with gallbladder perforation presented at an older age (53 versus 60 years; P < 0.05), had more cardiovascular comorbidity (29% versus 50%; P < 0.05) and postoperative complications (19% versus 37%; P < 0.05), and required more ICU admissions (9% versus 33%; P < 0.001) and longer hospital stays (8 versus 13 days; P < 0.001). Early cholecystectomy within 24 h improved outcome (P < 0.05).

CONCLUSIONS

Gallbladder perforation is a rare complication of cholelithiasis that occurs more often in men, Hispanics, and older patients. It is rarely diagnosed preoperatively. Late operative intervention is associated with increased morbidity, mortality, number of ICU admissions, and long postoperative hospital stays. An early cholecystectomy strategy may lead to improved outcomes but may be difficult to implement and may not be cost-effective.

Current practices and future prospects for the management of gallbladder polyps: A topical review

A gallbladder polyp is an elevation of the gallbladder mucosa that protrudes into the gallbladder lumen. Gallbladder polyps have an estimated prevalence in adults of between 0.3%-12.3%. However, only 5% of polyps are considered to be "true" gallbladder polyps, meaning that they are malignant or have malignant potential. The main radiological modality used for diagnosing and surveilling gallbladder polyps is transabdominal ultrasonography. However, evidence shows that other modalities such as endoscopic ultrasound may improve diagnostic accuracy. These are discussed in turn during the course of this review. Current guidelines recommend cholecystectomy for gallbladder polyps sized 10 mm and greater, although this threshold is lowered when other risk factors are identified. The evidence behind this practice is relatively low quality. This review identifies current gaps in the available evidence and highlights the necessity for further research to enable better decision making regarding which patients should undergo cholecystectomy, and/or radiological follow-up.

Gallbladder Pathology in Morbid Obesity

BACKGROUND

Obese patients are at increased risk for biliary disease. The prevalence and type of gallbladder pathology in morbidly obese patients was evaluated, and compared with a non-obese control group.

METHODS

A consecutive series of obese patients (n=478) who had undergone bariatric surgery with concurrent routine cholecystectomy and a consecutive group of organ donors (n=481) were compared. Gallbladder pathology was defined as: cholelithiasis, cholecystitis, cholesterolosis, or normal pathology.

RESULTS

Mean age of obese patients and of donors was 42 +/- 9 and 43 +/- 17 years respectively and mean BMI was 52 +/- 10 and 27 +/- 7 kg/m2 respectively, P<0.05. There were more females in the obesity group (88% vs 47%, P<0.0001). 31% of obese patients and 7% of controls had a previous cholecystectomy (P<0.0001). 21% of the obese and 72% of the controls had normal gallbladder pathology (P<0.0001). Overall, obese patients had a higher incidence of cholelithiasis (25% vs 5%, P<0.0001), cholecystitis (50% vs 17%, P<0.0001), and cholesterolosis (38% vs 6%, P<0.0001) compared with controls. Obese patients with BMI <50 were more likely than those with BMI > or =50 to have normal gallbladder pathology (27% vs 14%, P<0.001). Female patients were more likely to have undergone previous cholecystectomy than males in both the obese group (34% vs 11%, P<0.001) and the control group (12% vs 2%, P<0.0001). Normal pathology was more common in male patients (80% vs 63%, P<0.0001) and patients <50 years (76% vs 66%, P<0.05) in the control group.

CONCLUSIONS

Obese patients have an increased incidence of benign gallbladder disease than a group of controls, and the relative risk appears to be positively correlated with the level of increase in the BMI. Obesity appears to change the effect of age and gender on gallbladder pathology.

Hospital volume and patient outcomes after cholecystectomy in Scotland: retrospective, national population based study

OBJECTIVES

To define associations between hospital volume and outcomes following cholecystectomy, after adjustment for case mix using a national database.

DESIGN

Retrospective, national population based study using multilevel modelling and simulation.

SETTING

Locally validated administrative dataset covering all NHS hospitals in Scotland.

PARTICIPANTS

All patients undergoing cholecystectomy between 1 January 1998 and 31 December 2007.

MAIN OUTCOME MEASURES

Mortality, 30 day reoperation rate, 30 day readmission rate, and length of stay.

RESULTS

We identified 59,918 patients who had a cholecystectomy in one of 37 hospitals: five hospitals had high volumes (>244 cholecystectomies/year), 10 had medium volumes (173-244), and 22 had low volumes (<173). Compared with low and medium volume hospitals, high volume hospitals performed more procedures non-electively (17.1% and 19.5% v 32.8%), completed more procedures laparoscopically (64.7% and 73.8% v 80.9%), and used more operative cholangiography (11.2% and 6.3% v 21.2%; χ(2) test, all P<0.001). In a well performing multivariable analysis with bias correction for a low event rate, the odds ratio for death was greater in both the low volume (odds ratio 1.45, 95% confidence interval 1.06 to 2.00, P=0.022) and medium volume (1.52, 1.11 to 2.08, P=0.010) groups than in the high volume group. However, in simulation studies, absolute risk differences between volume groups were clinically negligible for patients with average risk (number needed to treat to harm, low v high volume, 3871, 1963 to 17,118), but were significant in patients with higher risk. In models accounting for the hierarchical structure of patients in hospitals, those in medium volume hospitals were more likely to undergo reoperation (odds ratio 1.74, 1.31 to 2.30, P<0.001) or be readmitted (1.17, 1.04 to 1.31, P=0.008) after cholecystectomy than those in high volume hospitals. Length of stay was shorter in high volume hospitals than in low (hazard ratio for discharge 0.78, 0.76 to 0.79, P<0.001) or medium volume hospitals (0.75, 0.74 to 0.77, P<0.001). These differences were also only of clinical significance in patients at higher risk.

CONCLUSIONS

There is wide variation among hospitals in the management of gallstone disease and an association between higher hospital volume and better outcome after a cholecystectomy. The relative risk of death is lower in high volume centres, and although absolute risk differences between volume groups are significant for elderly patients and patients with comorbidity, they are clinically negligible for those at average risk.

Sonography of the gallbladder: significance of striated (layered) thickening of the gallbladder wall

Sonographic identification of thickening of the gallbladder wall that consists of multiple striations (alternate hypoechoic and hyperechoic layers) has been considered strong evidence of the presence of acute cholecystitis. We studied 27 patients in whom sonograms showed striated thickening of the gallbladder wall to determine the diagnostic significance of this finding. Striations were classified as focal or diffuse. Sonograms were correlated with pathologic findings in 16 patients and with clinical diagnoses and laboratory findings in 11. Patients were categorized as having cholecystitis with or without gangrene or edema of the gallbladder wall unrelated to gallbladder disease. Striated thickening of the gallbladder wall was due to cholecystitis in 10 patients, and all 10 had gangrenous changes at surgery or at pathologic examination. Striations were focal in eight of these patients and diffuse in two. Striated thickening of the gallbladder wall was due to edema of the wall unrelated to gallbladder disease in 17 patients. Causes included congestive heart failure (n = 4), renal failure (n = 5), liver disease (hepatic failure [n = 1], hepatitis [n = 6]), ascites (n = 2), hypoalbuminemia (n = 3), pancreatitis (n = 1), blockage of the lymphatic/venous drainage of the gallbladder (n = 2), and prominent Rokitansky-Aschoff sinuses (n = 1). More than one abnormality was present in five patients. Striations were focal in 11 of these patients and diffuse in six. The sonographic finding of striated gallbladder wall thickening is no more specific for cholecystitis than the observation of gallbladder wall thickening by itself, and it may occur in a variety of diseases. However, in the clinical setting of acute cholecystitis, the presence of striations suggests gangrenous changes in the gallbladder. The extent of the striations (focal or diffuse) is not useful in predicting the cause of the striated gallbladder wall thickening.

Routine surgical pathology in general surgery

BACKGROUND

Although pathological analysis provides the definitive diagnosis for most resection specimens, recent evidence suggests that such analysis may be omitted for certain routine samples. This was a retrospective analysis of the value of routine histopathological examination performed in daily general surgical practice.

METHODS

All specimens from routine appendicectomies, cholecystectomies, haemorrhoidectomies and inguinal hernia repairs performed between 1993 and 2002 were included. The analysis included a comparison of histological and macroscopic diagnoses, review of preoperative and peroperative findings, and an evaluation of the consequences of routine histopathological assessment on patient management and costs.

RESULTS

With the exception of hernia specimens, the rate of submission for routine pathological evaluation was 100 per cent. No hernia sac specimen from more than 2000 interventions revealed aberrant histological findings. Of 311 haemorrhoidectomy specimens three showed malignancy, all of which had a suspicious macroscopic appearance. Of 1465 appendices, only one (0.1 per cent) had a potentially relevant histological diagnosis that was not suspected macroscopically. Among 1523 cholecystectomy specimens, all adenomas (0.6 per cent) and carcinomas (0.4 per cent) were suspected macroscopically or developed in association with a known disease.

CONCLUSION

The rarity of incidental histological findings relevant to patient management, especially in the absence of macroscopic abnormalities, suggests that routine histological examination of certain specimens may be omitted. A more elementary role for macroscopic examination of the specimen by the surgeon and the pathologist is proposed.

Comparison of preoperative serum CA19-9 levels with results of diagnostic imaging modalities in patients undergoing laparotomy for suspected pancreatic or gallbladder disease

A prospective, blinded study of CA19-9 in 2,467 patients having abdominal surgery yielded 356 patients with pancreatic, gallbladder, and biliary disease who submitted coded preoperative serum specimens. In this group, there were 84 patients with pancreatic cancer and 24 patients with gallbladder-biliary cancer; the remainder had benign lesions. The recorded imaging data and marker results were merged with the patients' demographic, clinical, and surgical data and tissue diagnoses for analysis. Receiver operator character calculation suggested that a reference value of 100 U/ml for CA19-9 was appropriate rather than the 37-40 U/ml value most frequently employed and yielded a specificity of 97% in the 467 operated patients with a sensitivity of 8.3% for all nonpancreatic-biliary cancers and 62% overall for these lesions. In the more diagnostically challenging nonicteric patients, CA19-9 sensitivity was 55%, specificity was > 99%, positive predictive value (PPV) was 97%, and negative predictive value (NPV) was 88%. When CA19-9 results were combined with those from endoscopic retrograde cholangiopancreatography, ultrasound (US), or computed tomography (CT), the PPV, and especially the NPV were increased. The addition of carcinoembryonic antigen results did not affect overall results. The addition of CA19-9 results to ambiguous or indeterminant imaging interpretation clearly improved the combined specificity, sensitivity, and PPV, but the change was less impressive, albeit positive, for NPV. The combination of CA19-9 and CT (or US) is a reasonable, cost-effective, noninvasive approach to establishing the diagnosis of pancreatic, cholangitic, or biliary cancer in nonicteric patients. Although no single procedure or combination of procedures was found to detect early, small lesions, CA19-9 is clearly a clinically useful adjunct to imaging in nonjaundiced patients suspected of having these malignancies.

The hyperplastic cholecystoses: cholesterolosis and adenomyomatosis

Cholesterolosis and adenomyomatosis, two diseases of the gallbladder that are unrelated to cholelithiasis or cholecystitis, are detected on oral cholecystograms with considerable frequency. These disorders are of uncertain etiology, and it is also unclear if they cause clinical symptoms. Cholesterolosis is the result of the accumulation of triglycerides and esterified sterols in macrophages in the lamina propria. The abnormality is unassociated with cholesterol gallstones, supersaturation of bile with cholesterol, hyperlipidemia, obesity, or atherosclerosis. Adenomyomatosis involves hyperplasia of the tissues of the gallbladder wall with outpouches of the mucosa similar to diverticula of the colon. In this report, the pathology, etiology, clinical and radiologic features, and treatment of these two entities are reviewed.

Learning curve of transumbilical single incision laparoscopic cholecystectomy (SILS): a preliminary study of 80 selected patients with benign gallbladder diseases

BACKGROUND

Transumbilical single incision laparoscopic surgery (SILS) is a new laparoscopic procedure in which only one transumbilical incision is made, demonstrated as a scarless procedure. Here we report a single-center preliminary experience of transumbilical single incision laparoscopic cholecystectomy (SILC) in the treatment of benign gallbladder diseases, defining a single surgeon's learning curve.

METHODS

A total of 80 patients underwent SILC successfully by a single experienced laparoscopic surgeon. The operation was performed following the routine LC procedure. Then the perioperative demographics were recorded and the operative time was used to define the learning curve.

RESULTS

The study group included 27 male and 53 female patients with gallstones (56 cases), cholesterol polyps (16 cases), an adenomatous polyp (3 cases), adenomyomatosis (1 case), or complex diseases (4 cases), and all consented to undergo SILC. No patient was converted to normal LC or open surgery. There were no perioperative port-related or surgical complications. The average operative time was 46.9 ± 14.6 min. The average postoperative hospital stay was 1.8 ± 1.3 days. The learning curve of the SILC procedures for this series of selected patients confirmed that SILC is a feasible, safe, and effective approach to the treatment of benign gallbladder diseases.

CONCLUSIONS

For experienced laparoscopic surgeons, SILC is an easy and safe procedure. Patients benefit from milder pain, a lower incidence of port-related complications, better cosmesis, and fast recovery. The SILC procedure may become another option for the treatment of benign gallbladder diseases for selected patients.