James Ellsmere

Does multidetector-row CT eliminate the role of diagnostic laparoscopy in assessing the resectability of pancreatic head adenocarcinoma?

BackgroundWe hypothesized that the high-quality images from multidetector-row computed tomography (MDCT) would lead to improved sensitivity and specificity for predicting resectable pancreatic head adenocarcinoma, thus diminishing the value of staging laparoscopy.MethodsForty four consecutive patients underwent thin-section dual-phase MDCT to stage their tumor, followed by an attempted pancreaticoduodenectomy. Four radiologists who were blinded to the operative outcome reviewed the scans and graded the presence of distant and nodal metastases, as well as the degree of arterial and portal involvement. The radiologic criteria for resectability were no distant metastasis, a patent portal vein, and <50% arterial involvement.ResultsThe overall resectability for this cohort was 52% (23/44). The 21 unresectable cases, included five liver metastases, three peritoneal metastases, and 13 locally invasive tumors. The negative margin resection rate was 34% (15/44). There were no portal vein resections. The sensitivity and specificity of MDCT for predicting resectability were 96% (22/23) and 33% (7/21), respectively. In this cohort, the positive and negative predictive values were 61% (22/36) and 87.5% (7/8), respectively. As determined by univariate logistic regression, only the degree of arterial involvement was a significant predictor of resectability (p = 0.02). As determined by multivariate logistic regression using both arterial and portal involvement, arterial involvement was predictive (p = 0.03) but portal vein involvement was not (p = 0.45).ConclusionsDespite the improvements in image quality obtained with multidetector-row technology, CT imaging remains a relatively nonspecific test for predicting resectability in patients with adenocarcinoma of the head of the pancreas. Minimally invasive modalities with higher specificity, particularly laparoscopy, continue to have an important role in staging pancreatic head adenocarcinoma.

A Navigation System for Augmenting Laparoscopic Ultrasound

Establishing image context is the major difficulty of performing laparoscopic ultrasound. The standard techniques used by transabdominal ultrasonographers to understand image orientation are difficult to apply with laparoscopic instruments. In this paper, we describe a navigation system that displays the position and orientation of laparoscopic ultrasound images to the operating surgeon in real time. The display technique we developed for showing the orientation information uses a 3D model of the aorta as the main visual reference. This technique is helpful because it provides surgeons with important spatial cues, which we show improves their ability to interpret the laparoscopic ultrasound.

Intraoperative ultrasonography during planned liver resections: why are we still performing it?

BackgroundIntraoperative ultrasonography (US) is used in many centers before oncologic liver resections to detect additional tumors and to evaluate the relationship of tumors to major vascular structures. As preoperative imaging improves, it is expected that the diagnostic yield from intraoperative US will diminish. In this study we attempt to determine if fewer unrecognized tumors were being detected and whether intraoperative US is having less impact on surgical decision making.MethodsWe compared 50 consecutive cases (mean age = 57.2 ± 10 years; 27 men) who underwent laparotomy for a planned resection of primary liver malignancies or metastases between September 2003 and July 2005 with 50 consecutive cases (mean age = 56.9 ± 14 years; 25 men) between January 1999 and September 2003. Dedicated intraoperative liver US was performed or supervised by a gastrointestinal radiologist using a 5.0-MHz linear- or curvilinear-array transducer during each procedure.ResultsThe rate of detecting unrecognized tumors has not changed significantly (14% vs. 20%, p = 0.70). The use of US to establish the relationship between tumor and the vasculature has not changed (48% vs. 60%, p = 0.23). The percentage of cases where the US findings were responsible for altering surgical management was 20% for both groups. The resection rate was 72% for both groups. The negative resection margin rate has also not changed significantly (86% vs. 69%, p = 0.09).ConclusionsDespite the advances in cross-sectional imaging, the frequency of unrecognized tumors found during intraoperative liver US and its use for surgical guidance has not changed significantly. Currently routine intraoperative US alters the management of approximately one fifth of our patients undergoing attempted liver resection for primary malignancies or metastases.

Multiscale segmentation of the aorta in 3D ultrasound images

Fast, reliable segmentation of the abdominal aorta from three dimensional ultrasound remains a difficult problem. Standard methods based on local information like thresholding, region growing or active contours fail in separating the arteries from the veins and suffer from the lack of homogeneity of the vessel intensity and from the partial contour information. We propose to use a model-based multiscale detection of the vessels centerlines based on a cylindrical model with circular cross-section, and adapted from previous work. Our method provides a set of centerlines and an estimate of the vessel radii along each line. After an interactive selection of the desired lines, a model of the aorta is generated using the radii information and compared to a manual segmentation. This model can also be locally improved using a level set technique in order to stick to the contours of the image and to allow non-circular cross-section.

Endoscopic interventions for weight loss surgery

In this paper we review the state‐of‐the‐art in endoscopic interventions for obesity treatment and make best practice recommendations for weight loss surgery (WLS). We performed a systematic search of English‐language literature published between April 2004 and June 2008 in MEDLINE and the Cochrane Library on WLS and endoscopic interventions, endoscopically placed devices, minimally invasive surgery, image‐guided surgery, endoluminal surgery, endoscopic instrumentation, interventional gastroenterology, transluminal surgery, and natural orifice transluminal surgery. We also searched the literature on endoscopic interventions and WLS and patient safety. We identified 36 pertinent articles, all of which were reviewed in detail; assessed the current science in endoscopic interventions for WLS; and made best practice recommendations based on the latest available evidence. Our findings indicate that endoscopic interventions and endoscopically placed devices may provide valuable approaches to the management of WLS complications and the primary management of obesity. Given the rapid changes in endoscopic technologies and techniques, systematic literature review is required to address issues related to the emerging role of endoluminal surgery in the treatment of obesity. These interventions should be a high priority for development and investigation.

Bariatric Surgery Training: Getting Your Ticket Punched

Laparoscopic bariatric surgery has gained popularity but has been proven to be a technically challenging set of operations that requires a long learning curve. Trainees must acquire advanced laparoscopic skills and knowledge of the perioperative care of the bariatric patient. The challenge is to ensure that those surgeons performing gastric bypass, gastric banding, and duodenal switch procedure are trained appropriately. In the past, very different opportunities have been available for the general surgeon seeking to practice bariatric surgery. Early on, many surgeons began performing bariatric surgery without any formal training. Later, weekend courses, mini-fellowships, and formal minimally invasive surgery/bariatric fellowships were established. Today, best practice requires an intensive training experience and ongoing commitment to the field.

Freehand Ultrasound Reconstruction Based on ROI Prior Modeling and Normalized Convolution

3D freehand ultrasound imaging is becoming a widespread technique in medical examinations. This imaging technique produces a set of irregularly spaced B-scans. Reconstructing a regular grid from these B-scans is a challenging problem that enables the visualization and further analysis of the acquired data. This paper focuses on extending an existing method [1] to define the output reconstruction grid based on principal component analysis (PCA). Our method introduces a model for the region of interest (ROI) in order to adapt the grid to the ROI. In addition, a technique based on normalized convolution is proposed for the interpolation problem. A new applicability function based on the correlation function of a linear probe is used to avoid inter-resolution cell blurring.

Benchmarking hospital outcomes for laparoscopic adjustable gastric banding.

BackgroundSince the Food and Drug Administration (FDA) approval of laparoscopic adjustable gastric bands (LAGB) in June 2001, the number LAGB procedures performed in the United States has increased exponentially. This study aimed to benchmark the authors’ initial hospital experience to FDA research trials and evidence-based literature.MethodsOver a 2-year period, 87 consecutive patients with a mean age of 43 years (range, 21–64 years) and a body mass index of 45.6 kg/m2 (range, 35–69 kg/m2) underwent an LAGB procedure at the authors’ institution. The authors conducted a retrospective review of the outcomes including conversion, reoperation, mortality, perforation, erosion, prolapse, port dysfunction, excess weight loss, and changes in comorbidities, then compared the data with published benchmarks.ResultsGender, age, and body mass index were comparable with those of other series. Perioperative adverse events included acute stoma obstruction (n = 1) and respiratory complications (n = 2). Delayed complications included gastric prolapse (n = 4) and port reservoir malposition (n = 4). Five bands were explanted. The mean follow-up period was 14 months (n = 79). The mean percentage of excess weight loss was 30% (range, 4.7–69%) at 6 months, 41% (range, 9.6–82%) at 12 months, and 47% (range, 14–92%) at 24 months. Comorbidities resolved included diabetes (74%), hypertension (57%), gastroesophageal reflux disease (55%) and dyslipidemia (38%).ConclusionsThe short-term outcomes for LAGB were comparable with published benchmarks. With adequate weight loss, most patients achieve significant improvement in obesity-related illnesses. With new bariatric accreditation standards and mandates required for financial reimbursement, hospitals will need to demonstrate that their clinical outcomes are consistent with best practices. The authors’ early experience shows that LAGB achieves significant weight loss with low mortality and morbidity rates. Despite a more gradual weight loss, most patients achieve excellent weight loss with corresponding improvement of comorbidities within the first 2 years postoperatively.

Endoluminal instrumentation is changing gastrointestinal surgery.

Advances in endoluminal instrumentation and technology are enabling endoscopists to perform increasingly sophisticated procedures. Indications for these procedures are likely to expand as outcomes studies show they are efficacious and cost-effective. This article highlights several recent advances in endoluminal suturing, dissecting, and ligating and discusses the impact of these advances on the practice of gastrointestinal surgery. Endoluminal suturing offers select patients with gastroesophageal reflux disease a safe and effective alternative to laparoscopic surgery. Devices designed for endoluminal hemostasis and endoscopic mucosal resection can be used effectively for a broader range of applications and are already being used to perform transluminal surgery in animal models; human trials are forthcoming. Gastrointestinal surgeons should support efforts to critically evaluate endoluminal techniques because they have an opportunity to improve care. Surgical residents planning careers in gastrointestinal surgery need to understand endoscopic techniques and consider their training opportunities.

Reply to: Re: Intraoperative ultrasonography during planned liver resections remains an important surgical tool ((2007) 21: 1280–1283)

We thank Prof. Cerwenka for his informative and insightful comments regarding our article. He highlights the importance of high-quality preoperative imaging, and that oftentimes this necessitates repeating studies using liverspecific protocols. Contrast-enhanced liver ultrasonography looks promising but its use in the USA is still considered investigational. Overall, his clinical experience is very similar to ours. Despite the impressive advances in crosssectional imaging over the last decade, intraoperative liver ultrasonography still plays an important role in guiding the surgical management of many patients with both benign and malignant liver lesions.