Tumor Ablation Using 3-Dimensional Electromagnetic-Guided Ultrasound Versus Standard Ultrasound in a Porcine Model.

Introduction. The objective of this study was to compare the placement of ablation needles using 3-dimensional electromagnetic-guided ultrasound (guided) to standard ultrasound guidance (standard) in both laparoscopic surgery and open surgery. Endpoints for this study included targeting accuracy and number of required needle withdrawals and reorientations. Methods. Using a porcine model, fiducial markers were placed into the kidney and liver to represent tumors. Navigation and identification of target sites was achieved using standard or guided ultrasound. Intraprocedural observations as well as the number of needle placement attempts per target were recorded. Three board-certified general surgeons performed the navigation and ablation procedures. After completion of the navigation and ablation procedures, necropsy was performed. The position of the ablation zones relative to the fiducial markers was recorded. Results. A total of 48 procedures were performed across 6 animals (50% open and 50% laparoscopic). Overall, the guided ablations required 50% fewer attempts to successfully target the marker (P = .01). There was a 62% reduction of attempts for guided laparoscopic ablation (P = .006). On subgroup analysis of laparoscopic ablation, the benefit remained for liver (P = .041) ablations, but not for renal ablations (P = .093). There was no significant difference between the groups with regard to targeting accuracy (91.3% guided vs 95.4% standard, P = .58). Conclusions. The number of targeting attempts required during laparoscopic ablation procedures was significantly less with guided than with standard ultrasound, particularly for laparoscopic ablation of liver lesions. These findings suggest that the guided ultrasound can potentially reduce complications during laparoscopic ablation procedures.

The effect of alcohol on Sirt1 expression and function in animal and human models of hepatocellular carcinoma (HCC).

INTRODUCTION: Chronic heavy alcohol use is an independent risk factor for developing hepatocellular carcinoma (HCC). Sirtuin-1 (Sirt1) is a NAD+-dependent deacetylase implicated in alcohol-induced liver injury and overexpressed in human HCC. The aims of this study were to investigate Sirt1 expression in mouse models of HCC and chronic EtOH-feeding, and in human HCC cells expressing alcohol metabolizing enzymes. METHODS: C57BL/6 and B6C3 mice were injected with DEN and randomized to receive drinking water (DW) or EtOH-DW for 8 weeks at 36 weeks. Livers were analyzed for HCC incidence, size, and Sirt1 expression. In parallel, human HepG2 cells or HepG2 cells transfected to express ADH and CYP2E1 (VL-17a cells) were treated with alcohol (0-50 mM) and/or CAY10591 (Sirt1 activator) or EX-527 (Sirt1 inhibitor). RESULTS: B6C3 mice exhibited significantly elevated Sirt-1 expression vs. C57BL/6 mice and Sirt-1 expression was elevated in HCC vs. non-tumor liver. However, EtOH-feeding did not further affect Sirt1 expression in mice of either background despite EtOH increasing HCC size and incidence in B6C3 mice. In vitro, EtOH treatment significantly decreased Sirt1 expression in VL-17a-cells and stimulated cell growth, an effect not observed in HepG2 cells. The effects of ethanol on VL-17a cells were abrogated by pretreatment with CAY10591. CONCLUSIONS: Sirt1 expression correlates with susceptibility to form HCC, but is not further affected by alcohol feeding. Conversely Sirt1 expression and function is impacted by alcohol metabolism capacity in human HCC cells in vitro. These discrepancies in Sirt1-expression-function may reflect differences in enzyme expression compared to activity, or more complex changes in genes targeted for deacetylation during tumor progression in the setting of chronic alcohol ingestion.

Optimal ablation volumes are achieved at submaximal power settings in a 2.45-GHz microwave ablation system.

INTRODUCTION: Local ablative therapies, including microwave ablation (MWA), are common treatment modalities for in situ tumor destruction. Currently, 2.45-GHz ablation systems are gaining prominence because of the shorter application times required. The aims of this study were to determine optimal power and time to ablation volume (AbV) ratios for a new 1.8-mm-2.45-GHz antenna using ex vivo tissue models. METHODS: The 1.8-mm-2.45-GHz Accu2i MWA system was employed to perform ablations in bovine liver, porcine muscle, and porcine kidney ex vivo. Whole tissues were prewarmed (35°C) and multiple ablations performed at power settings of 60 to 180 W for 2- to 6-minute time intervals. Postablation, tissues were dissected, AbVs calculated, and correlations to power and time settings made. RESULTS: Significant increases in AbV were measured between each of the time points for a constant power setting in all 3 tissues. Increasing power settings led to significant increases in AbV at power settings ≤140 W. However, no significant increase in AbV was obtained at power settings >140 W. CONCLUSIONS: Optimal efficiency for MWA using a new 1.8-mm-2.45-GHz system is achieved at settings of ≤140 W for 6 minutes in a range of ex vivo tissue and no additional benefit occurs by increasing the power setting to 180 W in these tissues.

Laparoscopic microwave ablation of human liver tumours using a novel three-dimensional magnetic guidance system.

BACKGROUND: Accurate antenna placement is essential for effective microwave ablation (MWA) of lesions. Laparoscopic targeting is made particularly challenging in liver tumours by the needle's trajectory as it passes through the abdominal wall into the liver. Previous optical three-dimensional guidance systems employing infrared technology have been limited by interference with the line of sight during procedures. OBJECTIVE: The aim of this study was to evaluate a newly developed magnetic guidance system for laparoscopic MWA of liver tumours in a pilot study. METHODS: Thirteen patients undergoing laparoscopic MWA of liver tumours gave consent to their participation in the study and were enrolled. Lesion targeting was performed using the InnerOptic AIM™ 3-D guidance system to track the real-time position and orientation of the antenna and ultrasound probe. RESULTS: A total of 45 ablations were performed on 34 lesions. The median number of lesions per patient was two. The mean ± standard deviation lesion diameter was 18.0 ± 9.2 mm and the mean time to target acquisition was 3.5 min. The first-attempt success rate was 93%. There were no intraoperative or immediate postoperative complications. Over an average follow-up of 7.8 months, one patient was noted to have had an incomplete ablation, seven suffered regional recurrences, and five patients remained disease-free. CONCLUSIONS: The AIM™ guidance system is an effective adjunct for laparoscopic ablation. It facilitates a high degree of accuracy and a good first-attempt success rate, and avoids the line of site interference associated with infrared systems.

Microwave ablation for hepatic malignancies: a multiinstitutional analysis.

OBJECTIVE: This study hypothesized that tumor size, number of tumors, surgical approach, and tumor histology significantly affected microwave ablation (MWA) success and recurrence-free survival. BACKGROUND: Although many hepatobiliary centers have adopted MWA, the factors that influence local control are not well described. METHODS: Consecutive patients with hepatic malignancy treated by MWA were included from 4 high-volume institutions (2003-2011) and grouped by histology: hepatocellular carcinoma (HCC), colorectal liver metastases, neuroendocrine liver metastases, and other cancers. Independent significance of outcome variables was established with logistic regression and Cox proportional hazards models. RESULTS: Four hundred fifty patients were treated with 473 procedures (139 HCC, 198 colorectal liver metastases, 61 neuroendocrine liver metastases, and 75 other) for a total of 875 tumors. Median follow-up was 18 months. Concurrent hepatectomy was performed in 178 patients (38%), and when performed was associated with greater morbidity. Complete ablation was confirmed for 839 of 865 tumors (97.0%) on follow-up cross-sectional imaging (10 were unevaluable). A surgical approach (open, laparoscopic, or percutaneous) had no significant impact on complication rates, recurrence, or survival. The local recurrence rate was 6.0% overall and was highest for HCC (10.1%, P = 0.045) and percutaneously treated lesions (14.1%, P = 0.014). In adjusted models, tumor size 3 cm or more predicted poorer recurrence-free survival (hazard ratio: 1.60, 95% CI: 1.02-2.50, P = 0.039). CONCLUSIONS: In this large data set, patients with 3 cm or more tumors showed a propensity for early recurrence, regardless of histology. Higher rates of local recurrence were noted in HCC patients, which may reflect underlying liver disease. There were no significant differences in morbidity or survival based on the surgical approach; however, local recurrence rates were highest for percutaneously ablated tumors.

Comparison of culture and molecular techniques for microbial community characterization in infected necrotizing pancreatitis.

BACKGROUND: Infected necrotizing pancreatitis is associated with significant morbidity and mortality. Peripancreatic fluid cultures may fail to identify all the infecting organisms. The aim of this study was to compare the bacterial biome of peripancreatic fluid from infected necrotizing pancreatitis patients using 16S ribosomal RNA (rRNA) DNA deep sequencing and quantitative polymerase chain reaction (qPCR) targeting the 16S rRNA gene versus standard laboratory culture. MATERIALS AND METHODS: Peripancreatic fluid was collected during operative or radiologic intervention and samples sent for culture. In parallel, microbial DNA was extracted, qPCR targeting the 16S rRNA gene and 16S rRNA PCR amplification followed by Illumina deep sequencing were performed. RESULTS: Using culture techniques, the bacterial strains most frequently identified were gram-negative rods (Escherichia coli, Klebsiella pneumoniae) and Enterococcus. Samples in which culture results were negative had copy numbers of the 16S rRNA gene close to background in qPCR analysis. For samples with high bacterial load, sequencing results were in some cases in good agreement with culture data, whereas in others there were disagreements, likely due to differences in taxonomic classification, cultivability, and differing susceptibility to background contamination. Sequencing results appeared generally unreliable in cases of negative culture where little microbial DNA was input into qPCR sequencing reactions. CONCLUSIONS: Both sequencing and culture data display their own sources of bias and potential error. Consideration of data from multiple techniques will yield a more accurate view of bacterial infections than can be achieved by any single technique.

Laparoscopic transgastric endolumenal cystogastrostomy and pancreatic debridement.

BACKGROUND: Cystogastrostomy is commonly performed for internal drainage of pancreatic pseudocysts (PP) and concomitant debridement of walled-off pancreatic necrosis (WOPN). While an open approach to cystogastrostomy is well established, an optimal minimally invasive technique continues to evolve. This laparoscopic transgastric endolumenal cystogastrostomy presented here allows for a large cystogastrostomy with complete debridement of necrosis and internal drainage through a minimally invasive approach. METHODS: We performed a retrospective review of 22 patients with symptomatic PP/WOPN treated with attempted laparoscopic transgastric endolumenal cystogastrostomy (Lap-TEC) and pancreatic debridement. Short- and long-term outcomes were assessed. RESULTS: From November 2006 to March 2013, a total of 22 Lap-TEC/pancreatic debridement procedures were attempted; 15 were completed laparoscopically. The median age of the cohort was 49.5 ± 12 years (range = 18-71), average body mass index = 29.1 kg/m(2), 77 % had an ASA score ≥ 3, and 10 were female. Gallstones were the most common etiology (50 %), and median time between initial presentation and surgery was 86 days (range = 0-360). Median operative time and estimated blood loss were 213 min and 100 cc, respectively. Forty-one percent of the patients were admitted to the ICU postoperatively and the average length of stay was 14 days (range = 4-50). Median follow-up was 2 months (range = 0-62.5), with one patient having a procedure-related complication. No other reoperations, late complications, or mortalities occurred. All patients had resolution of their symptoms and fluid collections. CONCLUSION: This technique of internal drainage via Lap-TEC and pancreatic debridement has been successful in achieving primary drainage and relieving symptoms of PP/WOPN with no mortality and minimal morbidity.

Altered lysophosphatidic acid (LPA) receptor expression during hepatic regeneration in a mouse model of partial hepatectomy.

BACKGROUND: Hepatic regeneration requires coordinated signal transduction for efficient restoration of functional liver mass. This study sought to determine changes in lysophosphatidic acid (LPA) and LPA receptor (LPAR) 1-6 expression in regenerating liver following two-thirds partial hepatectomy (PHx). METHODS: Liver tissue and blood were collected from male C57BL/6 mice following PHx. Circulating LPA was measured by enzyme-linked immunosorbent assay (ELISA) and hepatic LPAR mRNA and protein expression were determined. RESULTS: Circulating LPA increased 72 h after PHx and remained significantly elevated for up to 7 days post-PHx. Analysis of LPAR expression after PHx demonstrated significant increases in LPAR1, LPAR3 and LPAR6 mRNA and protein in a time-dependent manner for up to 7 days post-PHx. Conversely, LPAR2, LPAR4 and LPAR5 mRNA were barely detected in normal liver and did not significantly change after PHx. Changes in LPAR1 expression were confined to non-parenchymal cells following PHx. CONCLUSIONS: Liver regeneration following PHx is associated with significant changes in circulating LPA and hepatic LPAR1, LPAR3 and LPAR6 expression in a time- and cell-dependent manner. Furthermore, changes in LPA-LPAR post-PHx occur after the first round of hepatocyte division is complete.

Lysophosphatidic acid receptor expression and function in human hepatocellular carcinoma.

BACKGROUND: Lysophosphatidic acid (LPA) is a ubiquitously expressed phospholipid that regulates diverse cellular functions. Previously identified LPA receptor subtypes (LPAR1-5) are weakly expressed or absent in the liver. This study sought to determine LPAR expression, including the newly identified LPAR6, in normal human liver (NL), hepatocellular carcinoma (HCC), and non-tumor liver tissue (NTL), and LPAR expression and function in human hepatoma cells in vitro. METHODS: We determined LPAR1-6 expression by quantitative reverse transcriptase polymerase chain reaction, Western blot, or immunohistochemistry in NL, NTL, and HCC, and HuH7, and HepG2 cells. Hepatoma cells were treated with LPA in the absence or presence of LPAR1-3 (Ki16425) or pan-LPAR (α-bromomethylene phosphonate) antagonists and proliferation and motility were measured. RESULTS: We report HCC-associated changes in LPAR1, 3, and 6 mRNA and protein expression, with significantly increased LPAR6 in HCC versus NL and NTL. Analysis of human hepatoma cells demonstrated significantly higher LPAR1, 3, and 6 mRNA and protein expression in HuH7 versus HepG2 cells. Treatment with LPA (0.05-10 µg/mL) led to dose-dependent HuH7 growth and increased motility. In HepG2 cells, LPA led to moderate, although significant, increases in proliferation but not motility. Pretreatment with α-bromomethylene phosphonate inhibited LPA-dependent proliferation and motility to a greater degree than Ki16425. CONCLUSIONS: Multiple LPAR forms are expressed in human HCC, including the recently described LPAR6. Inhibition of LPA-LPAR signaling inhibits HCC cell proliferation and motility, the extent of which depends on LPAR subtype expression.

The use of a novel MUC1 antibody to identify cancer stem cells and circulating MUC1 in mice and patients with pancreatic cancer.

BACKGROUND AND OBJECTIVES: MUC1 is over-expressed and aberrantly glycosylated in >60% of human pancreatic cancer (PC). Development of novel approaches for detection and/or targeting of MUC1 are critically needed and should be able to detect MUC1 on PC cells (including cancer stem cells) and in serum. METHODS: The sensitivity and specificity of the anti-MUC1 antibody, TAB 004, was determined. CSCs were assessed for MUC1 expression using TAB 004-FITC on in vitro PC cell lines, and on lineage(-) cells from in vivo tumors and human samples. Serum was assessed for shed MUC1 via the TAB 004 EIA. RESULTS: In vitro and in vivo, TAB 004 detected MUC1 on >95% of CSCs. Approximately, 80% of CSCs in patients displayed MUC1 expression as detected by TAB 004. Shed MUC1 was detected serum in mice with HPAF-II (MUC1(high) ) but not BxPC3 tumors (MUC1(low)). The TAB 004 EIA was able to accurately detect stage progression in PC patients. CONCLUSIONS: The TAB 004 antibody may be explored as a therapeutic targeting agent for CSCs in PC. The TAB 004 EIA detected circulating MUC1 in a stage-dependent manner in patients with PC and thus may be explored as a PC stage diagnostic biomarker.

Diet-induced obesity and ethanol impair progression of hepatocellular carcinoma in a mouse mesenteric vein injection model.

BACKGROUND: Hepatocellular carcinoma (HCC) is a rapidly increasing cancer whose known risk factors are chronic ethanol abuse, viral hepatitis infection, and aflatoxin exposure. Obesity, an emerging HCC risk factor, is reaching epidemic proportions in developed nations. This study investigated the effects of diet-induced obesity (DIO) and chronic ethanol consumption on HCC progression in mice in vivo. METHODS: In this study, C57BL/6 DIO mice and lean litter mates were maintained on a 60% (high-fat diet [HFD]) diet or a 10% (control diet [CD]) kcal% fat diet for 7 weeks before they were weaned to 10/20% ([v/v], alternating days) ethanol in drinking water (EtOH) or maintenance on drinking water (H(2)O) alone. Hepatic tumor formation was initiated by intrahepatic Hepa1-6 cell (6 × 10(6) cells) inoculation 6 weeks later via the mesenteric vein. RESULTS: The animals receiving the HFD showed decreased tumor incidence and area of hepatic foci versus the CD animals maintained on H(2)O alone. The action of EtOH suppressed tumor incidence further in both the CD and the HFD mice. Serologic analysis showed no significant differences in liver enzymes among the groups. Protein analysis demonstrated increased P450 2E1 (CYP2E1) in the groups maintained on EtOH, an effect exacerbated by HFD. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis demonstrated increased tumor necrosis factor-alpha (TNF-α) expression in HFD HCC mice (H(2)O and EtOH) concomitant with decreased transforming growth factor-beta (TGF-ß) expression. CONCLUSIONS: Although obesity and EtOH consumption are known risk factors for HCC initiation and development, the data in this study suggest that these factors impair progression of established tumors within the liver.

Obesity, but not ethanol, promotes tumor incidence and progression in a mouse model of hepatocellular carcinoma in vivo.

BACKGROUND: Hepatocellular carcinoma (HCC) is a major global health burden. Although chronic, heavy alcohol abuse is an established risk factor for HCC, obesity is emerging as an increasingly important factor in HCC development. Given that other risk factors for HCC act synergistically to promote tumorigenesis, we investigated the effects of diet-induced obesity and chronic ethanol consumption on tumor progression. METHODS: A diethylnitrosamine (DEN) mouse model of HCC was established and mice randomized to control (CD; 10 % kcal% fat) or high fat (HFD; 60 % kcal% fat diet) at 5 weeks of age. At 35 weeks, mice were randomized to 10/20 % ethanol (EtOH) in drinking water (alternate days), or drinking water (H2O) alone. Tumor incidence/size were measured and confirmed. Liver tissue was analyzed for oxidative stress and EtOH-metabolizing enzymes and serum analyzed for liver function and nutritional status. RESULTS: DEN treatment induced HCC formation in 60 % CD-H2O mice (6 of 10), an effect exacerbated by HFD (89 %). Tumors in HFD animals occupied significantly more of the liver than mice on CD. EtOH-feeding did not impact HCC incidence or tumor size. HFD resulted in increased liver injury and liver:body weight ratio regardless of EtOH consumption. Increased tumor incidence was associated with elevated hepatic oxidative stress in the absence of changes in intrinsic antioxidant (glutathione) levels. CONCLUSIONS: Obesity independently promoted HCC formation in the absence or presence of a known hepatocarcinogen (DEN), and enhanced both number and size of hepatic tumors independent of chronic EtOH consumption in mice.

Evaluation of an innovative, cordless ultrasonic dissector.

Ultrasonic thermal energy is commonly used for dissection and vessel ligation. This study compared HARMONIC ACE and Sonicision Cordless Ultrasonic Dissector (SCUD). The devices were used in an in vivo porcine model to coagulate 189 arteries up to 5 mm. Seal times were similar: SCUD, 5.2 ± 1.7 s; ACE, 4.9 ± 1.5 s (P = .20). Burst pressures for SCUD and AVE were 578 ± 284 and 605 ± 288 mm Hg, respectively (P = .48). Stratification by vessel diameter yielded similar results. In all, 17 applications resulted in seal failure on either the proximal or distal side, with no difference between SCUD (4.4%) and ACE (6.6%; P = .37). Histological examination of 48 specimens showed similar thermal spreads: 1.06 ± 0.05 versus 1.08 ± 0.05 mm for SCUD and ACE, respectively (P = .82). In 41 timed mesenteric transections, SCUD required 24.8 ± 4.9 s, which was significantly less than the 33.8 ± 5.4 s for ACE (P < .0001), with no bleeding in either group. SCUD and ACE showed similar vessel seal times, burst pressures, thermal spreads, and seal failure rates. SCUD was more efficient than ACE in mesenteric transection.

Microwave ablation using 915-MHz and 2.45-GHz systems: what are the differences?

OBJECTIVES: This study was conducted to evaluate differences between 915-MHz and 2.45-GHz microwave ablation (MWA) systems in the ablation of hepatic tumours. METHODS: A retrospective analysis of patients undergoing hepatic tumour MWA utilizing two different systems over a 10-month period was carried out. RESULTS: Data for a total of 48 patients with a mean age of 58 ± 1.24 years were analysed. A total of 124 tumours were ablated; 72 tumours were ablated with a 915-MHz system and 52 with a 2.45-GHz system. Mean tumour diameters were 1.7 ± 0.1 cm in the 915-MHz group and 2.5 ± 0.2 cm in the 2.45-GHz group (P < 0.01). Mean ablation time per burn was 8.1 ± 0.3 min in the 915-MHz group and 4.0 ± 0.1 min in the 2.45-GHz group (P < 0.01). The mean number of burns per lesion was 2.0 ± 0.1 in the 915-MHz group and 1.7 ± 0.1 in the 2.45-GHz group (P < 0.05). The mean ablation time per lesion was 9.7 ± 0.7 min in the 915-MHz group, and 6.6 ± 0.6 min in the 2.45-GHz group (P < 0.01). The 2.45-GHz system demonstrated a better correlation between ablation time and tumour size (r(2) = 0.6222) than the 915-MHz system; (r(2) = 0.0696). Mean total energy applied per lesion, and energy applied per cm, were greater with the 915-MHz system (P < 0.05 and P < 0.01, respectively). Total energy applied per lesion was similarly correlated for the 2.45-GHz (r(2) = 0.6263) and 915-MHz (r(2) = 0.7012) systems. Mean total energy applied per cm/min was greater with the 2.45-GHz system (P < 0.05). CONCLUSIONS: Both 915-MHz and 2.45-GHz MWA systems achieve reproducible hepatic tumour ablation. The 2.45-GHz system achieves equivalent, but more predictable and faster ablations using a single antenna system.

Adrenocortical carcinoma with intracaval extension to the right atrium: resection on cardiopulmonary bypass.

CASE PRESENTATION: A 28-year-old woman presented with dyspnea on exertion and elevated testosterone level. A 21 × 19 cm right adrenal mass was found invading the liver and inferior vena cava (IVC); tumor thrombus extended to the right atrium on transthoracic echocardiogram. OPERATIVE PROCEDURE: Median sternotomy and extended right subcostal incisions were made. Inferior surface of liver was mobilized and vessels to the tumor divided and packed. The IVC was isolated and cardiopulmonary bypass initiated. Tumor was excised from IVC and tumor thrombus extracted. After partial IVC wall resection, the venotomy was closed. The right atrium was explored for remaining thrombus. Segment 7 of the liver was resected with division of right hepatic vein. The patient was removed from bypass, and the cut surface of liver was reinforced with chromic sutures. Intraoperative ultrasound demonstrated no remaining tumor thrombus. Provisional closure was achieved with wound vac, and the next day, the patient's wound was closed primarily. OUTCOME: On postoperative day 3, the patient was extubated; she was discharged on day 12. Pathology revealed well-differentiated adenocarcinoma weighing 2.3 kg with negative surgical margins. Two months after surgery, she received radiation for suspected lumbar vertebral metastasis and initiated mitotane therapy. Follow-up surveillance scans showed no evidence of disease. DISCUSSION: Adrenocortical carcinoma is a rare malignancy presenting frequently in advanced stage with poor prognosis. Chemotherapy is often only moderately effective, while complete surgical resection is potentially curative. In this patient, excellent short-term outcome was achieved through radical surgical resection. We continue to monitor her closely for evidence of recurrence.

Invasive biliary mucinous cystic neoplasm: a review.

OBJECTIVES: Biliary mucinous cystic neoplasms (BMCNs) are recently redefined rare liver tumours in which insufficient recognition frequently leads to an incorrect initial or delayed diagnosis. A concise review of the subtle, sometimes non-specific, clinical, serologic and radiographic features will allow for a heightened awareness and more comprehensive understanding of these entities. METHODS: Literature relating to the presentation, diagnosis, treatment, pathology and outcomes of BMCNs and published prior to March 2012 was reviewed. RESULTS: Biliary mucinous cystic neoplasms most commonly occur in females (≥60%) in the fifth decade of life. Clinical symptoms, serologic markers and imaging modalities are unreliable for diagnosis of BMCNs, which leads to misdiagnosis in 55-100% of patients. Perioperative cyst aspiration is not recommended as invasive BMCNs can only be differentiated from non-invasive BMCNs by microscopic evaluation for the presence of ovarian-type stroma. Intraoperative biopsy and frozen section(s) are essential to differentiate BMCNs from other cystic liver lesions. The treatment of choice is complete excision and can result in excellent survival with initial correct diagnosis. CONCLUSIONS: A low threshold for considering BMCN in the differential diagnosis of cystic liver lesions and increased attentiveness to its subtle diagnostic characteristics are imperative. The complete surgical resection of BMCNs and the use of appropriate nomenclature are necessary to improve outcomes and accurately define prognosis.

Poor resident-attending intraoperative communication may compromise patient safety.

BACKGROUND: Prior research suggests that hierarchy in medicine may impact communication and patient safety. This study examined the factors that influence surgical trainees in expressing their opinion in the operating room and the consequences this might have on patient safety. METHODS: An anonymous survey of general surgery, gynecology, and orthopedic surgery residents and attendings was conducted at a teaching institution in 2010. Separate surveys were used for attendings and for trainees consisting of 26 and 27 questions, respectively, with 17 questions in common. The surveys assessed whether the surgical hierarchy interfered with the residents voicing concerns about patient safety. Survey data was compiled, and χ2, Fisher exact tests, and the Wilcoxon rank sum test were used depending on the normality of the data. RESULTS: Thirty-eight trainees and 23 attendings participated in the survey; 74%-78% of trainees and attendings recalled an incident where the trainee spoke up and prevented an adverse event. While all attendings reported that they encourage residents to question their intraoperative decision making, only 55% of residents agreed (P<0.01). Residents indicated that they were more likely to voice their opinion with some attendings than with others based on their personality. Both groups agreed that the hierarchical structure of general surgical residency is necessary. CONCLUSION: Our findings indicate that resident attending intraoperative communication can prevent adverse patient events. Trainees often feel impaired in voicing their concerns to their attendings. Strategies that improve resident attending communication intraoperatively are needed as they are likely to enhance patient safety.

Collagen-elastin ratio predicts burst pressure of arterial seals created using a bipolar vessel sealing device in a porcine model.

BACKGROUND: Bipolar electrosurgical devices are used to generate rapid and efficient hemostasis in a wide range of surgical procedures. Of the factors that influence seal integrity, vessel (artery) diameter has been considered the most important variable. In this study we hypothesized that the relative ratio of the components that form the seal (collagen and elastin) determine the degree of vessel distensibility and play an equally important role in defining seal strength. METHODS: Porcine carotid, renal, iliac, and femoral arteries were sealed using a bipolar electrosurgical device in vivo. Following removal, arterial diameter was measured and vessels' seals tested for arterial burst pressure (ABPr). Samples were then analyzed histologically and biochemically for collagen and elastin content. RESULTS: Arteries with the highest collagen-elastin ratio (C/E) (renal) consistently demonstrated significantly higher burst pressures than those arteries with lower C/E ratios (iliac and femoral) independent of artery diameter. CONCLUSION: Using arteries of distinct anatomical origin and physiological function, we demonstrate that total collagen content, and more specifically C/E ratio, in porcine arteries is a more accurate predictor of ABPr than vessel size alone.

Evaluation of composite mesh for ventral hernia repair.

INTRODUCTION: Composite mesh prostheses incorporate the properties of multiple materials for ventral hernia repair. This study evaluated a polypropylene/ePTFE composite mesh with a novel internal polydioxanone (PDO) absorbable ring. METHODS: Composite mesh was placed intraperitoneally in 16 pigs through an open laparotomy and explanted at 2, 4, 8, and 12 weeks. Intraabdominal adhesions were measured laparoscopically. Host tissue in-growth was assessed histologically and tensiometrically. Degradation of the internal PDO ring component was also measured tensiometrically. Appropriate statistical tests were used, and P ≤.05 indicated significance. RESULTS: No adhesions were formed in 50% of the grafts explanted at 8 weeks and 25% of grafts explanted at 12 weeks. There were significantly more vascular structures at 8 weeks, 73.5 ± 28, compared with 2 weeks, 6.75 ± 2 (P ≤.01). The T-peel force at the mesh-host tissue interface was not significantly different among time points. The absorbable PDO ring underwent complete degradation by 12 weeks. CONCLUSIONS: This composite mesh was associated with minimal intraabdominal adhesions, progressive in-growth of host tissues, and complete degradation of a novel internal PDO ring that aided mesh positioning. This composite hernia mesh showed a favorable performance in a porcine model of open ventral hernia repair.

Real-time three-dimensional guided ultrasound targeting system for microwave ablation of liver tumours: a human pilot study.

OBJECTIVES: This study aimed to evaluate a novel three-dimensional ultrasound (US) guidance system for use in hepatic microwave ablation (MWA). METHODS: An in vitro assessment was performed in which users with different degrees of experience were evaluated for accuracy in targeting phantom lesions embedded in agar using US alone, or US in conjunction with the InVision™ System (IVS). An eight-patient pilot trial of the IVS was then performed in the setting of open hepatic MWA, in which lesions would otherwise have been targeted with conventional US. RESULTS: In vitro studies demonstrated that the IVS significantly improved targeting accuracy at all levels of operator experience (novice, beginner and expert). In the human trial, a total of 31 tumours were targeted and all lesions were hit in one pass, as assessed by independent US image observations. There were no adverse operative events; however, there was minor line-of-sight interference with the infra-red tracking mechanism when some lesions high on the dome of the liver were targeted. CONCLUSIONS: The IVS significantly increased the accuracy of complex targeting procedures of phantom lesions and enhanced targeting in an eight-patient clinical pilot study. During the accrual phase of this pilot study, the development of improved non-optical tracking hardware obviated the requirement to maintain a direct line of sight. The trial was then halted prematurely in order to focus on the application of the IVS utilizing this non-optical modality.