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(BQ) Part 1 book General surgery prepare for the MRCS key articles from the surgery journal presentation of content: Anatomy of the anterior abdominal wall and groin, secretory functions of the gastrointestinal tract, physiology of malabsorption, abdominal access techniques,... and other contents.
https://kat.cr/user/Blink99/ General Surgery: Prepare for the MRCS Key articles from the Surgery Journal Series Editor W E G Thomas MS FRCS FSACS(Hon) Consultant Surgeon, Honorary Senior Lecturer, Sheffield University; Member of Council and past Vice President of the Royal College of Surgeons of England Clinical Editor Michael G Wyatt MSc MD FRCS FRCSEd (ad hom) Consultant Surgeon, Freeman Hospital, Newcastle‐upon‐Tyne; Honorary Reader, Newcastle University; Clinical Editor, SURGERY; Honorary Secretary, The Vascular Society of Great Britain and Ireland; Member of the Court of Examiners for the Intercollegiate MRCS Edinburgh London New York Oxford Philadelphia St Louis Sydney Toronto 2015 © 2015 Elsevier Ltd. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the publisher (other than as may be noted herein). First edition 2015 First published in Surgery: 2012‐2014 ISBN978‐0‐7020‐6802‐7 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data A catalog record for this book is available from the Library of Congress Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications. It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions. To the fullest extent of the law, neither the publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or https://kat.cr/user/Blink99/ otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. Content Strategist: Laurence Hunter Content Development Specialist: Kim Benson Designer: Miles Hitchen Preface Surgery has been at the forefront of providing quality articles especially designed for candidates sitting the Intercollegiate examinations for over 20 years. Now technology is making these quality articles available not only in printed form but also on‐line. However the increasing demand for easy access to quality information, has prompted the preparation of a series of ‘e‐books’ based on surgical specialisation bringing together articles written by experienced authorities on each topic as published in Surgery. The journal Surgery covers the whole of the surgical syllabus as represented by the Intercollegiate Surgical Curriculum. Each topic is covered in an up‐to‐date article by an acknowledged authority on the subject every three years, thus ensuring contemporaneous coverage of the core curriculum. These collections of articles for each surgical specialty are not only ideal for revision for the Intercollegiate examinations, but will also be invaluable for the specialist registrar in each surgical specialty. We warmly welcome this innovative approach and trust that this collection of ‘e‐books’ will significantly enhance the learning experience of all surgical trainees and also provide a useful update for all seeking to keep abreast with the latest advances in their particular branch of surgery. WEGT MGW Sheffield and Newcastle 2015 https://kat.cr/user/Blink99/ About The Surgery Journal Surgery is a continually updated, evidence‐based, learning resource for trainees. Based entirely on the Intercollegiate Surgical Curriculum, Surgery gives you high‐calibre and concise articles designed to help you pass the MRCS exams. Surgery also provides consultant surgeons with a clear didactic framework to help train residents and junior staff. Each issue of Surgeryis themed and contains both basic scientific and clinical sections. The basic science articles cover anatomy, physiology and pathology while the clinical sections cover all of the skills across all of the topics required for and tested in the MRCS exams. The authors are all recognized specialists and Surgery is curated by a highly qualified team of Editors. This ebook brings together a comprehensive collection of all the articles on general surgery. Over 100articles in total create a comprehensive compendium of surgical knowledge that will be a perfect resource for anyone preparing for the MRCS. Also included are MCQ and extended matching questions to test your understanding of the contents of this ebook. If after reading this ebook you would like to subscribe to Surgery please go to www.surgeryjournal.co.uk. Issue Editors forGeneral Surgery Sean Carrie MB ChB FRCS (ORL) Consultant Ear, Nose & Throat Surgeon, Freeman Hospital, Newcastle upon Tyne, UK Umesh Khot MBBS, MS, FRCS (England), FRCS (Gen) Consultant General and Colorectal Surgeon, Singleton and Morrison Hospitals, Swansea, UK Peter Lamb MBBS MD FRCS Consultant Upper Gastrointestinal Surgeon, Royal Infirmary, Edinburgh, UK Anthony Lander FRCS (Paed) Consultant Paediatric Surgeon, Birmingham Children’s Hospital, Birmingham, UK Soroush Sohrabi MD, PHD, MRCS Specialist Registrar in Vascular Surgery, Hull Royal Infirmary, Hull, UK Helen M Sweetland MD FRCS (Ed) Reader in Surgery and Honorary Consultant Surgeon, Cardiff and Vale University LHB,Cardiff, UK W E G Thomas MS FRCS FSACS(Hon) Consultant Surgeon, Honorary Senior Lecturer, Sheffield University; Member of Council and Past Vice President of the Royal College of Surgeons of England, UK Peter Vowden MS FRCS Consultant Vascular Surgeon, Bradford Teaching Hospitals NHS Foundation Trust; Visiting Professor of Wound Healing Research, University of Bradford, Bradford, UK https://kat.cr/user/Blink99/ This page intentionally left blank Surgery is an authoritative, comprehensive collection of educational reviews that present the current knowledge and practice of surgery Surgery also indicates recent advances that improve the understanding of disease and the safe and effective treatment of patients It comprises concise and systematically updated contributions that are produced over a three-year cycle Surgery is an excellent didactic tool to help consultant surgeons train their junior staff to become safe and competent surgeons Series editor W E G Thomas MS FRCS FSACS(Hon) Consultant Surgeon, Honorary Senior Lecturer, Sheffield University, Member of Council and past Vice President of the Royal College of Surgeons of England Clinical editor Michael G Wyatt MSc MD FRCS FRCSEd (ad hom) Consultant Surgeon, Freeman Hospital, Newcastle upon Tyne; Honorary Reader, Newcastle University; Clinical Editor, SURGERY; Honorary Secretary, The Vascular Society of Great Britain and Ireland, and Member of the Court of Examiners for the Intercollegiate MRCS Editorial adviser Harold Ellis CBE DM FRCS FRCOG Emeritus Professor of Surgery, London University Clinical Anatomist, Guy’s, King’s and St Thomas’s School of Biomedical Science, London, UK Editorial Board Mary Murphy MB BCh, BAO, FRCS (SN) Consultant Neurosurgeon Royal Free Hospital, London, UK Ian Nesbitt MBBS FRCA DICM(UK) Consultant in Anaesthesia and Critical Care Freeman Hospital, Newcastle-upon-Tyne, UK Andreas Adam FRCP FRCR FRCS Professor of Interventional Radiology King’s College London, UK Joseph Shalhoub BSc MBBS MRCS (Eng) FHEA PhD Specialty Registrar in General Surgery, London Deanery and Joint Vice President, Association of Surgeons in Training Jon Anderson FRCS(CTh) Consultant Cardiothoracic Surgeon Hammersmith Hospital NHS Trust, London, UK Frank CT Smith BSc MD FRCS Consultant Senior Lecturer in Surgery Bristol Royal Infirmary, Bristol, UK Emily Jane Baird MBChB MRCS (Glasgow) Trauma and Orthopaedic Specialty Registrar, West of Scotland Rotation; and President of the British Orthopaedic Trainees Association Helen Sweetland MD FRCS(Ed) Reader in Surgery and Honorary Consultant Surgeon Cardiff and Vale NHS Trust, UK Frank Carey FRCPath Professor and Consultant Histopathologist Ninewells Hospital, Dundee, UK Christopher R Chapple MD FRCS(Urol) FEBU Visiting Professor, Sheffield Hallam University Consultant Urological Surgeon, Royal Hallamshire Hospital, UK Ben Cresswell MBChB FRCS(Gen Surg) Consultant Hepatopancreatobiliary Surgeon The Basingstoke Hepatobiliary Unit North Hampshire Hospital, UK Michael J Kelly MChir FRCS MRCP(UK) Consultant Colorectal Surgeon, Leicester, UK and National Advisor Colorectal Cancer, NHS Improvement Court of Examiners RCSEng William Wallace MBChB(Hon) PhD FRCPE FRCPath Consultant Pathologist and Honorary Senior Lecturer Royal Infirmary of Edinburgh, UK Robert Wilkins MA DPhil (Oxon) Lecturer in Physiology Department of Physiology, Anatomy & Genetics St Edmund Hall, University of Oxford, UK Mark Wilkinson PhD FRCS(Orth) Senior Lecturer in Orthopaedics University of Sheffield, UK Consultant Orthopaedic Surgeon Northern General Hospital, Sheffield, UK Surgical and Clinical Anatomy for the MRCS exam Peter Lamb MBBS FRCS(Eng) MD FRCS(Gen) Consultant Upper GI and General Surgeon Royal Infirmary of Edinburgh, UK Series editors Anthony Lander PhD DCH FRCS(Paed) Senior Lecturer in Paediatric Surgery and Consultant Paediatric Surgeon, Birmingham Children’s Hospital, UK This series is available only on the website: www.surgeryjournal.co.uk Harold Ellis CBE DM MCh FRCS FRCOG London Vishy Mahadevan MB BS PhD FRCS London Founder editors John S P Lumley MS FRCS London John L Craven MD FRCS York https://kat.cr/user/Blink99/ Abdominal Surgery Volume 30:6 June 2012 A great revision guide for the MRCS and beyond 290 Anatomy of the anterior abdominal wall and groin Vishy Mahadevan 257 Adult groin hernias Terry Irwin Alison McCoubrey 296 Secretory functions of the gastrointestinal tract Henrik Isackson Christopher C Ashley 261 Investigation of the acute abdomen Janette K Smith Dileep N Lobo 306 Physiology of malabsorption Jonathan D Nolan Ian M Johnston Julian RF Walters 268 Investigation of abdominal masses Quat Ullah Richard A Nakielny Gynaecological causes of abdominal pain Shehnaaz Jivraj Andrew Farkas 310 BASIC SCIENCE ABDOMINAL SURGERY TEST YOURSELF Abdominal access techniques (including laparoscopic access) Cara Baker Ralph Smith Sukhpal Singh 275 Wound dehiscence and incisional hernia Nicholas J Slater Robert P Bleichrodt Harry van Goor 282 MCQs 315 Based entirely on the Intercollegiate Surgical Curriculum Issue Editor W E G Thomas ms frcs fsacs(hon) Consultant Surgeon, Honorary Senior Lecturer, Sheffield University, Member of Council and Past Vice President of the Royal College of Surgeons of England www.surgeryjournal.co.uk ONLINE, IN PRINT, IN PRACTICE © 2012 Elsevier Ltd ISSN 0263-9319 EMERGENCY SURGERY Catheter in urinary bladder Pressure transducer Needle in aspiration port Monitor Urine-collecting tubing and bag Clamp on collecting tubing distal to aspiration port Figure Needle-puncture technique for the measurement of intra-abdominal pressure The transducer should be mounted at the height of the patient’s anterior-superior iliac spine in the mid-axillary line and zeroed to air at this level Clean the aspiration port and surrounding tubing of the patient’s urinary catheter using the alcohol wipe and lay the tubing on the sterile towel connected between the urinary catheter and the collecting tubing and allow free drainage of urine between measurements The AbVisor connects to an electronic pressure transducer and the FoleyManometer is a simple fluid manometer, gradated such that the fluid in the tubing (urine or saline flush) is displayed as mmHg Both devices have been shown to provide accurate measurements and both correspond closely to values obtained by direct intra-peritoneal recordings.8,9 A third device, which measures intra-gastric pressure via a nasogastric tube is also available (SiMon, Pulsion Medical, Munich, Germany) The interested reader is directed to the individual device websites for more information on their use Step Perform the measurement Wearing sterile gloves, disconnect the collecting tubing from the catheter and instill 25 ml of sterile saline into the bladder Reconnect the tubing and immediately clamp just distal to the injection port to ensure that there is a continuous column of fluid between the bladder and the aspiration port Insert the green needle to the collection tubing via the aspiration port and observe the monitor e a pressure reading should register Allow minutes for the pressure reading to settle before recording the measurement, then remove the needle and unclamp the tubing to allow urine to drain freely Dispose of your sharps safely and return the patient to the usual position (usually at 30 ‘head-up’ nursing position) The needle should be disposed of between measurements, but the transducer tubing can be reused if a sterile cap is applied Management of elevated IAP Elevated IAP can be treated by surgical or non-surgical interventions All cases of intra-abdominal hypertension (IAP 12e20 mmHg), should undergo non-surgical optimization,10 however the majority of cases of abdominal compartment syndrome (IAP >20 mmHg), will require surgical decompression Non-surgical management Treat any underlying pathology that may be driving the elevated IAP Optimize mean arterial blood pressure (>80 mmHg) to improve organ perfusion Optimize ventilator settings to minimize transmitted pressure, whilst preserving oxygenation Optimize analgesia and consider the use of pro-kinetic agents Use nasogastric and flatus tubes to reduce gaseous distension of the stomach and/or colon Use appropriate imaging to diagnose and guide percutaneous drainage of any intra-abdominal collections/ascites Commercial devices for the measurement of IAP There are several commercially produced devices for the measurement of IAP These devices have the advantage of being designed specifically for the purpose and allow faster measurements to be taken following the initial set-up, but are more expensive than the needle-puncture technique described above Two devices exist for the measurement of bladder pressure e the AbVisor (Wolf Tory, Utah, USA) and the FoleyManometer (Holtech Medical, Charlottenlund, Denmark) Both devices are SURGERY 31:11 584 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY Consider the use of neuromuscular blockade in ventilated patients e this manoeuvre may increase abdominal wall compliance and reduce IAP, but is often only a temporizing measure Temporary abdominal closure Several methods for temporary abdominal closure exist and the choice of technique will depend on a number of factors e including the available local expertise/materials, the underlying pathology and the anticipated duration of treatment There are five aims for treatment: control of IAP prevention of adhesions between the organs and the abdominal wall prevention of ‘loss of domain’ or retraction of the fascial edges protection of the integrity of the fascial edges control of fluid exudates/transudates The ‘bogota bag’ closure was one of the first techniques described to provide temporary abdominal closure e for this technique, the fascial edges are left open and a piece of plastic sheet (often an opened sterile intravenous fluid bag) is sutured continuously around the fascial edges Whilst this is a cheap and efficient solution, it has the drawback that the fascial edges can be damaged by the sutures, the closure is prone to leakage of peritoneal fluids and there is no prevention of adhesions The ‘modified vacuum pack sandwich technique’ carries the advantage of protecting the fascial edges, providing better control of peritoneal secretions and preventing adhesions e this should be considered the technique of choice for short-term use11 (Figure 2) Surgical management Surgical management of raised intra-abdominal pressure can be classified as pro-active or reactive and consists of leaving an open abdominal wound e a laparostomy For patients undergoing laparotomy in whom one or more risk factors for ACS exist, thought should be applied as to whether or not the abdomen should be proactively left open with a temporary dressing and definitive closure deferred for a later date Measuring the IAP ‘on-table’ before and after fascial closure may help guide this decision In patients with a closed abdomen and a diagnosis of ACS, failure to improve IAP following application of the non-surgical techniques listed above should mandate surgical decompression Surgical decompression is usually achieved by performing a long midline laparotomy, whereby the skin, subcutaneous tissues and fascia are opened and a temporary abdominal dressing applied, until such a time that the abdomen can be closed without elevated pressures Even following decompression, a tertiary ACS can arise and so decompressed patients must continue to undergo pressure monitoring until their illness has resolved and the abdomen has been closed An ‘open-abdomen’ is surprisingly well tolerated and carries minimal risk of further morbidity e in particular the risk of infective complications is low Prophylactic antibiotics are not required (unless used to treat an underlying diagnosis) and patients not need to be kept sedated or ventilated while the abdomen is left open (again, unless required by their underlying pathology) Pain is not usually a significant problem Techniques for temporary abdominal closure are described below Performing the modified vacuum pack sandwich technique Following laparotomy, divide the ligamentum teres between clips and take down at least half of the length of the falciform ligament by dividing it using diathermy midway between it’s attachment to the liver and the abdominal wall Place large bore (30F) non-suction tube drains along each paracolic gutter and into the pelvis e position the exit Suction drains Paracolic and pelvic tube drains Sterile adhesive dressing Soft plastic sheet covering abdominal viscera Abdominal wall defect Abdominal wall defect — viscera covered by soft plastic sheet Sterile adhesive dressing Suction drains Bowel loop Figure Modified vacuum-packed sandwich technique for temporary abdominal closure SURGERY 31:11 585 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY points of the drains as far laterally as possible on the anterior abdominal wall Place a soft plastic sheet (an opened bowel bag is ideal) over the abdominal organs, tucking it well down into the pelvis, each of the paracolic gutters and over the anterior surface of the liver (this prevents adhesions forming between the organs and the abdominal wall) Position at least two suction drains over the plastic sheeting, with one lying along the lower border of the plastic sheet as it meets the lower fascial edge e again, place the exit position of the drains as far laterally as possible Apply a sterile adhesive dressing sheet over the open abdomen, overlapping onto the skin as far laterally, cranially and caudially as possible Do not allow the edges of the dressing to overlie the drains and ensure that all edges are firmly ‘stuck down’ without air bubbles or creases e it is essential to thoroughly dry the skin before applying the dressing Open the suction drains, which will stick the self-adhesive dressing to the plastic sheet covering the organs where the two are in contact The tube drains will allow any peritoneal fluid to drain and the suction drains will remove any fluid collecting between the two sheets The dressing should be changed every 48e72 hours Figure Lateral releasing incisions to facilitate definitive fascial closure without tension degree of contamination The healing of open skin wounds may be expedited by the application of a simple ‘vac dressing’ once the underlying fascia is closed In some cases, a significant loss of domain will prevent primary fascial closure, even using the staged approach In such patients, a ‘component separation’ may be useful, whereby lateral releasing incisions are made e dividing the external oblique apponeurosis in a line running around cm lateral to the linea semilunaris, extending from the lower costal margin to the iliac crest.13 This manoeuvre, performed bilaterally will provide an extra 5e8 cm of fascial capacity (Figure 3) In a small minority of patients, despite lateral releasing incisions, fascial closure will still not be achieved In such cases, a planned incisional hernia is usually the safest solution, whereby the fascial defect is left open and a ‘skin-only’ closure performed.14 A delayed mesh repair of the abdominal wall can be performed at a later date, when the acute illness has resolved and control of concurrent sepsis or nutritional deficits has been addressed If skin-only closure is not feasible e it is possible to apply a split skin graft direct to the exposed omentum or even bowel loops, which can then be treated as a planned incisional hernia at a later date A Topical negative pressure dressing More recently, several topical negative pressure dressings have been developed which are effective at preventing adhesions, maintaining abdominal domain and preserving fascial edges.12 In addition, there is some emerging evidence that these devices may help to both control peritoneal fluid and also reduce visceral oedema and collections The key has been the development of composite dressings, which prevent exposure of bowel to the sponge on which the negative pressure is applied The dressings are expensive, however, and also require a dedicated controlled pressure pump with dressing changes required every 48e72 hours They are most suited to situations where an abdomen may need to be left open for sometime, as the lack of adhesions and preservation of abdominal domain will facilitate delayed fascial closure An example of such a system is the AbThera dressing (KCI, San Antonio, Texas, USA) e as before, full details can be found on the manufacturer’s website Definitive closure of laparostomy wounds The precise timing for definitive closure will vary on a case-bycase basis, however as vital signs, acidosis and the use of inotropic medications and/or high levels of ventillatory support begin to improve, it is usually safe to consider fascial closure In each case, IAP should be monitored closely in the perioperative period and a low threshold maintained for re-laparostomy if pressures were to increase In the majority of cases, it will be possible to achieve complete fascial closure at a single sitting, but if this is not possible, a staged approach can be adopted whereby the wound is closed gradually from each end over the course of several days Skin edges can be ‘freshened’, by light debridement back to healthy tissues and may be closed primarily over suction drains or else left open to heal by secondary intention, depending on the SURGERY 31:11 REFERENCES Nortje J, Gupta AK The role of tissue oxygen monitoring in patients with acute brain injury Br J Anaesth 2006; 97: 95e106 Tiwari A, Haq AI, Myint F, Hamilton G Acute compartment syndromes Br J Surg 2002; 89: 397e412 Malbrain ML, Chiumello D, Pelosi P, et al Prevalence of intraabdominal hypertension in critically ill patients: a multicentre epidemiological study Intensive Care Med 2004; 30: 822e9 Tal R, Lask DM, Keslin J, Livne PM Abdominal compartment syndrome: urological aspects BJU Int 2004; 93: 474e7 Malbrain ML, Cheatham ML, Kirkpatrick A, et al Results from the International Conference of Experts on intra-abdominal hypertension and abdominal compartment syndrome I Definitions Intensive Care Med 2006; 32: 1722e32 586 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY Cheatham ML, Safcsak K Is the evolving management of intraabdominal hypertension and abdominal compartment syndrome improving survival? Crit Care Med 2010; 38: 402e7 Kron IL, Harman PK, Nolan SP The measurement of intra-abdominal pressure as a criterion for abdominal re-exploration Ann Surg 1984; 199: 28e30 Cheatham ML, De Waele JJ, De Laet I, et al The impact of body position on intra-abdominal pressure measurement: a multicenter analysis Crit Care Med 2009; 37: 2187e90 Cresswell AB, Jassem W, Srinivasan P, et al The effect of body position on compartmental intra-abdominal pressure following liver transplantation Ann Intensive Care 2012; 2(suppl 1): S12 10 Cheatham ML, Malbrain ML, Kirkpatrick A, et al Results from the International Conference of Experts on intra-abdominal SURGERY 31:11 11 12 13 14 587 hypertension and abdominal compartment syndrome Ii Recommendations Intensive Care Med 2007; 33: 951e62 Navsaria PH, Bunting M, Omoshoro-Jones J, Nicol AJ, Kahn D Temporary closure of open abdominal wounds by the modified sandwichvacuum pack technique Br J Surg 2003; 90: 718e22 Bovill E, Banwell PE, Teot L, et al Topical negative pressure wound therapy: a review of its role and guidelines for its use in the management of acute wounds Int Wound J 2008; 5: 511e29 Howdieshell TR, Proctor CD, Sternberg E, Cue JI, Mondy JS, Hawkins ML Temporary abdominal closure followed by definitive abdominal wall reconstruction of the open abdomen Am J Surg 2004; 188: 301e6 Tremblay LN, Feliciano DV, Schmidt J, et al Skin only or silo closure in the critically ill patient with an open abdomen Am J Surg 2001; 182: 670e5 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY Imaging and radiological interventions for the acute abdomen employed in solid organ lesion characterisation or in the setting of non-acute inflammatory bowel disease Computed tomography (CT) is considered the workhorse in the setting of the acute abdomen given its reported accuracy, availability, reproducibility and speed Coverage usually extends from above the hepatic dome, affording lung base visualization to exclude basal pneumonia mimicking abdominal pathology, to the upper thigh incorporating the whole of the pelvis Portal venous phase imaging with intravenous contrast is the norm although timing and multi-phasic imaging can be altered/performed according to the clinical question posed Non-contrast CT is commonly employed in cases of renal colic or in excluding perforation when contrast is contraindicated Contrary to US, paucity of intra-abdominal fat in thin patients often makes interpretation of body CT difficult given the lack of fat interfaces Enteral contrast, oral or rectal, although beneficial in differentiating fluid filled bowel loops from contained collections is often impractical in the true acute scenario In the correct setting, enteral contrast remains a useful problem solving tool such as following complex bariatric surgery in delineating anatomy or in defining fistulous communications In our department, the protocols in Table have been introduced to aid optimal diagnostic accuracy Ionizing radiation is arguably the most significant limitation in CT, with an average effective radiation dose of 8e10 mSv for a CT abdomen/pelvis standard protocol, in comparison to a chest X-ray dose of 0.02 mSv and abdominal X-ray dose of 0.1e1.0 mSv Magnetic resonance imaging (MRI) is not commonly used in preliminary investigation of the acute abdomen although its inherent contrast resolution and absence of ionizing radiation give it advantages especially in the setting of pregnancy Limitations include lesser spatial resolution compared to CT, longer imaging time, susceptibility to movement artefact and need for MRI-compatible adjuncts make it less ideal in the acute setting when continued active resuscitation is required.2 Raymond Chung Andrew Hatrick Abstract The acute abdomen represents the surgical conundrum encompassing a wide set of differential diagnoses each with their own individual management paths The optimal imaging modality and characteristic appearances of common causes of the acute abdomen will be delineated Interventional radiological techniques and their use in supporting the surgical team will also be covered Keywords Abdominal aortic aneurysm; appendicitis; cholecystitis; diverticulitis; embolization; mesenteric ischaemia; pancreatitis; perforation haemorrhage; mesenteric Introduction The acute abdomen is the surgical conundrum with numerous potential differential diagnoses ranging from surgical emergencies to self-limiting conditions Clinical evaluation is often difficult and an accurate diagnosis based on medical history, physical examination findings and blood laboratory test results is often only possible in a small percentage Imaging plays an everincreasing role in diagnosing, identifying and prioritizing those requiring immediate intervention Plain radiography has conventionally been the first imaging examination performed given its wide availability With the advent and increasing accessibility of computed tomography (CT), plain radiography has a more limited role Radiographic techniques include supine, lateral decubitus and upright abdominal radiography, and erect chest radiography Ultrasound (US) is similarly a frequently used imaging technique although more dependent on the operator, body habitus and degree of bowel gas which hampers visualization US affords excellent visualization of solid abdominal viscera and to some respect, the alimentary tract.1 Its advantages include its absence of ionizing radiation and a potential use as dynamic/functional vascular imaging With operator interaction, sites of clinical tenderness and sonographic findings can be correlated Intravenous and oral contrast-enhanced US is more commonly Appendicitis Acute appendicitis is a commonly made diagnosis in the setting of acute right iliac fossa pain There is a wide list of differentials with potential mimics including, but not limited to, mesenteric adenitis, diverticulitis and inflammatory bowel disease Improved diagnostic imaging has helped guide appropriate management and reduce the number of negative appendectomies An example involves acute epiploic appendagitis which appears as circular fat lesions with surrounding inflammatory change, commonly anterior to sigmoid colon wall Recognition is important as this is usually a self-limiting disorder and does not warrant further surgical intervention US is widely used but bowel evaluation with US is inherently difficult given the imaging artefacts produced by bowel containing gas (Figure 1) A retrocaecal appendix is also often indiscernible by US However, it remains a useful tool in excluding potential mimics of appendicitis Given the absence of ionizing radiation, this is the preferred modality in paediatric patients and young adult females with a high clinical suspicion of gynaecological pathology Visualization of the appendix is commonly best appreciated with a linear high-frequency transducer using the graded Raymond Chung BSc MBBS MRCS FRCR is an Interventional Radiology Fellow at St George’s Healthcare NHS Trust, London, UK Conflicts of interest: none Andrew Hatrick MA MB BChir MRCP FRCR EBIR is an Interventional Consultant at Frimley Park Hospital NHS Foundation Trust, Frimley, UK Conflicts of interest: none SURGERY 31:11 588 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY mm (outer wall to outer wall diameter).4 Periappendiceal fluid or echogenic inflamed fat may also be seen CT has a higher diagnostic yield but its judicial use is abdicated given the potential radiation risk in an often younger patient population group It is therefore more commonly employed as a secondary line of investigation following a non-diagnostic US in those with remaining clinical ambiguity Various centres incorporate individual protocols in suspected appendicitis such as focused CT, unenhanced, and post-contrast (both intravenous and/or enteric) acquisitions A normal appendix can be variable in appearance measuring between and 20 cm in length It typically originates cm below the ileocaecal valve within the right lower quadrant.5 The appendiceal wall is usually less than mm in thickness and the outer diameter is less than mm Direct CT indicators of appendicitis include an enlarged appendiceal diameter, commonly considered as greater than mm, wall thickening over mm, and mural hyperenhancement often seen as a bull’s eye sign which indicates submucosal oedema Mural hypoenhancement may suggest underlying infarction and therefore impending perforation.6 Appendicoliths although commonly seen are not necessarily indicative of an acute episode Supportive CT findings of periappendiceal inflammation include mesenteric fat stranding, lateroconal fascial thickening, local fluid, and abscess formation Additional findings of extraluminal gas, abscess and appendiceal wall defects are consistent with appendiceal rupture Periappendiceal abscess is commonly managed by percutaneous drainage and interval appendicectomy.4 MRI is reserved for pregnant women and paediatric cases following an inconclusive US, given the lack of ionizing radiation There are no described teratogenic or carcinogenic effects of MRI to the fetus In acute appendicitis the wall often appears thickened, appearing hypointense on T1-weighted images and hyperintense on T2-weighted images Periappendiceal mesenteric inflammation will appears as hyperintense signal on T2-weighted imaging.2 CT protocols depending on clinical question posed Indication Intravenous contrast Enteric contrast phase of scan Acute abdominal pain e e.g appendicitis/ collection Bariatric patients post-surgery e leak/ stricture? Portal venous phase Oral water prior to (65e70 seconds) scan if possible Post-small bowel surgery e leak/ fistula/stricture? Post-colonic surgery e leak? Mesenteric angiogram e haemorrhage? Portal venous phase Dilute gastrografin (65e70 seconds) 20 ml in 200 ml water, 20e30 minutes prior to scan Portal venous phase Dilute 20 ml (65e70 seconds) gastrografin in litre water, started 1.5 hours prior to scan Portal venous phase With oral water Æ (65e70 seconds) rectal contrast with 20 ml gastrografin diluted in litre water, inserted via large Foley catheter and enema giving set Pre-contrast, arterial Nil phase, and portal venous phase studies with axial, coronal and sagittal reformats Table compression technique allowing displacement of overlying gasfilled loops during continuous imaging.3 The appendix is typically layered in appearance and compressible Sonographic evidence of appendicitis is dependent on demonstrating a blind-ending, non-compressible, luminal structure with mural hypervascularity, and measuring more than Cholecystitis US is now the most common imaging modality in the investigation of right upper quadrant pain Features include sonographic Murphy’s sign, gallbladder wall thickening and hypervascularity, and peri-cholecystic stranding Intramural fissuring is a recognized sign of impending gallbladder perforation requiring imminent intervention As the primary imaging modality, US is well-suited to establishing potential aetiology such as gallstones and potential complications including biliary tree dilatation Gallstones are characteristically visualized as hyperechoic foci with posterior acoustic shadowing Their presence and location within the biliary tree is important given the potential impact of retained stones within the biliary tree proper Sonographic appearances suggestive of biliary tree obstruction include CBD diameter greater than mm and tram-track appearances of the intrahepatic biliary ducts CT may at times provide supplementary findings such as gallbladder luminal gas and intraluminal membranes suggesting gangrenous cholecystitis.4 Radiography is of limited use with only 15% of gallstones containing calcium visible on plain X-rays Pneumobilia may on occasion be appreciable and radiography has historically diagnosed gallstone ileus Figure Ultrasound e blind-ending, non-compressible luminal structure consistent with an inflamed appendix Hypoechoic adjacent collection following perforation SURGERY 31:11 589 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY Radiological interventions for cholecystitis Percutaneous cholecystostomy (PC) involves percutaneous drainage insertion into the gallbladder lumen under imaging guidance.7 Indications include calculous or acalculous cholecystitis, biliary obstruction and cholangitis This affords reduction of infective load in the setting of acute sepsis allowing subsequent elective cholecystectomy It also serves as a means for stone extraction and potential stone dissolution therapy And can be used as a definitive treatment in very medically unfit patients who will not undergo further surgery PC is usually performed under local anaesthetic and US guidance, with drain insertion via a Seldinger technique (Figure 2) Both transhepatic or transperitoneal access have been described, though a transhepatic route may reduce the risk of subsequent bile leak following drain removal Pancreatitis CT is the imaging modality of choice in acute pancreatitis both in confirming diagnosis and monitoring for potential complications (Figure 3) In the acute setting the pancreas often appears oedematous with peripancreatic inflammatory change There may be surrounding fluid collections and additional complications such as splenic/portal venous thrombosis can be diagnosed The best yield is usually days post-onset of symptoms Enhanced portal venous phase imaging is most commonly employed, with pancreatic necrosis demonstrated as areas of absent enhancement US is useful in establishing presence of gallstones as a possible aetiological factor but otherwise of limited use in diagnosing pancreatitis In the setting of continued imaging surveillance of retroperitoneal collections, and in the absence of overlying bowel gas, US is a valuable imaging modality in reducing the ionizing radiation to the patient Figure Axial CT demonstrating peripancreatic stranding and pseudocyst formation following pancreatitis Radiological interventions for pancreatitis Image-guided percutaneous drainage is usually reserved for pancreatic abscesses and infected pancreatic necrosis CT-guided insertion of multiple large-bore drains into the retroperitoneal space allow irrigation and, depending on local surgical expertise, these also act as potential ports for percutaneous retroperitoneal endoscopic necrosectomy Chronic symptomatic pseudocysts can be drained into the stomach by way of a radiologically placed trans-gastric pancreatic cyst-gastrostomy stent Diverticulitis CT is the most common modality for investigation with characteristic findings of wall thickening in the presence of diverticulae and peri-enteric fat stranding Colorectal cancer is a potential mimic of diverticulitis and follow-up to resolution or direct visualization of the colonic mucosa is therefore prudent Focal short segment involvement with a luminal mass raises such a possibility and mandates further endoscopic evaluation following resolution of the acute episode.8 Segmental involvement of greater than 10 cm is more commonly associated with diverticulitis whilst mesocolic lymph nodes are often found in both conditions Potential complications such as perforation, bowel obstruction and fistulous communication are also best delineated by CT, aiding classification according to the Modified Hinchey system9 and thus guiding the treatment algorithm Perforation The clinical condition of perforation may be secondary to a variety of underlying aetiology thus rendering initial clinical presentation difficult to interpret Imaging is critical in establishing the diagnosis and in directing the correct surgical approach In reviewing bowel gas, it is important to establish whether it is intra- or extraluminal Conventionally an erect chest radiograph was used in the initial diagnostic pathway, indicated by a crescentic transradiancy beneath the diaphragm unexplained by normal stomach/bowel gas A common mimic is Chilaiditi syndrome in which gas-containing bowel is interposed in the Figure Tubogram following percutaneous cholecystostomy Contrast outlines gallbladder and biliary tree Filling defects within the gallbladder are in keeping with gallstones SURGERY 31:11 590 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY hepatodiaphragmatic space Supine abdominal radiographs may also demonstrate Rigler’s sign (Figure 4), falciform ligament sign, football sign, continuous diaphragms sign and gas triangles Rigler’s or double-wall sign describes sharp delineation of the bowel wall due to gas on both sides The falciform ligament, not usually visualized, is similarly perceptible when gas runs alongside it The football sign is secondary to gas occupying the more superficial anterior portion of the abdomen resulting in a circular lucency Intraluminal bowel gas is usually circular in appearance, whilst extraluminal gas may appear as triangles when seen between closely appositioned bowel loops.10 Previously, left lateral decubitus was useful in those too unwell to remain erect, pneumoperitoneum visualized as free gas interposed between the free edge of the liver and the lateral wall of the peritoneal cavity Retroperitoneal perforation is more commonly associated with duodenal and sigmoid aetiology and suggested by gas demarcating the kidney or psoas muscle.10 CT is now increasingly used both in diagnosing the pneumoperitoneum and depicting the underlying aetiology CT is able to detect smaller quantities of free intraperitoneal air (Figure 5), seen as free gas locules within the abdominal cavity not confined to a viscus Identification of the aetiology involves both direct and secondary imaging findings such as a focal defect or thickening of bowel wall, adjacent mesenteric inflammatory stranding and site of the greatest volume of extraluminal gas For example, a higher volume of gas around the stomach and liver may indicate a gastroduodenal perforation whilst gas in the pelvis suggests a colonic or appendicular aetiology Figure Axial CT demonstrating free intraperitoneal gas indicative of perforation Radiological interventions in perforation/diverticulitis/intraabdominal collection Surgical intervention is dependent upon a variety of patient and local institutional factors Patients that develop a complicating collection but are deemed unsuitable for operative intervention may benefit from radiological intervention by draining the intraabdominal collection/abscess Percutaneous drainage may be sufficient for definitive treatment or function as a bridge to surgery following improvement in patient haemodynamic stability/ condition Access and therefore suitability can initially be determined by review of the CT appearances Ideally, a direct percutaneous route should be available avoiding other intra-abdominal structures and visible vascularity Choice of imaging modality in guiding drain insertion is in part depicted by collection size, location, and presence of gas as this may make differentiation of a gas containing collection from closely adjacent gas containing bowel difficult As a general rule of thumb, superficial and predominantly fluid containing collections are readily amenable to US-guided drainage whilst deep and gascontaining collections are better inserted under CT guidance Cross-modality guidance may also be considered, in which initial puncture into the collection may be under US imaging, and further deeper manipulation afforded by a plethora of available catheters and guidewires under fluoroscopic guidance Large-bore drains can in this way be inserted into even deep retroperitoneal spaces that appear initially inaccessible Deep complex pelvic collections although initially daunting may still be accessible either by a posterior para-sacral approach under CT guidance or even via a transrectal approach, using an endoanal probe to guide aspiration and drain insertion Drain management is equally important in successful treatment as initial insertion Imaging post-drain insertion is often indicated to exclude drain complications, establish volume of remaining collection and therefore need for either drain re-siting or up-sizing Figure Abdominal radiograph demonstrating Rigler’s sign involving the recto-sigmoid colon SURGERY 31:11 591 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY Small bowel obstruction An underlying aetiology at the site of transition should be investigated such as adhesions, volvulus, neoplasm or hernia Adhesions are the commonest cause of SBO but are not usually perceptible on CT and more usually diagnosed by exclusion in the setting of known previous abdominal surgery On an occasion, kinking of bowel or extraluminal compression may suggest this aetiology.12 Prudent attention to hernial orifices is also crucial given their common occurrence Internal hernias are much more difficult to identify and often only suggested by a cluster of small bowel loops, mesenteric engorgement and displacement of mesenteric vascular structures (Table 2) Circumferential wall thickening over mm and pneumatosis intestinalis should raise the suspicion for complicating strangulation.4 US, although useful in differentiating mechanical obstruction and paralytic ileus by visualizing peristaltic movement, is often hampered by bowel gas In small bowel obstruction (SBO) imaging is useful in clarification of diagnosis, identifying the aetiology, site, degree (partial or complete) of obstruction, and potential complications Radiography is widely available and commonly used in the setting of the emergency department Small and large bowel can usually be differentiated by their location e small bowel centrally located and large bowel arranged peripherally, and fold pattern e small bowel folds named valvulae conniventes extends across the entire bowel lumen whilst large bowel folds are haustra only span part way across the lumen Bowel is considered dilated when small bowel transverse diameter is greater than cm and colonic diameter is greater than 5.5 cm Air-fluid levels over 2.5 cm are considered abnormal whilst small bubbles trapped between dilated loops e named ‘string of beads sign’ e are also suggestive of small bowel obstruction.10 Multiple airfluid levels in a step-ladder pattern has also been described Dilated and completely fluid filled bowel loops are also seen in small bowel obstruction, depicted on radiography as a gasless abdomen Hernial orifices e inguinal, femoral, umbilical and obturator e should be examined closely as an underlying cause Abdomino-pelvic CT (Figure 6) with intravenous contrast medium taken at the portal venous phase is usually obtained Oral contrast (water or dilute iodinated medium) may aid delineation in those with sub-acute or intermittent obstruction Diagnosis relies on depicting fluid-filled dilated small bowel loops with a clear change in bowel diameter at a defined transition point with collapsed bowel distal to this The small bowel faeces sign,11 faeces-like material in the distended small bowel immediately proximal to the transition site, may aid identification of the point of obstruction Large bowel obstruction (LBO) In order of frequency, aetiology of large bowel obstruction is colorectal cancer, sigmoid volvulus, and diverticulitis Radiography demonstrates dilated large bowel loops in which an important distinction is the presence of associated small bowel dilatation Absence of small bowel gas suggests a competent ileocaecal valve, thus increasing the risk of perforation Plain radiography is often helpful in establishing certain diagnoses than reviewing the CT alone, given reported characteristic findings In sigmoid volvulus, the sigmoid colon twists on its mesentery resulting in a massively dilated sigmoid loop arising from the pelvis and usually extending up to the right upper quadrant, known as the ‘coffee bean’ sign Caecal volvulus, less common than the sigmoid variety, shows marked distended loop extending from the right iliac fossa into the left upper quadrant The small bowel is often dilated whilst the distal large bowel is collapsed CT will show dilated loops of sigmoid colon with a bird-beak appearance of the afferent and efferent segments The mesenteric vessels may demonstrate a whirl-like pattern with enhanced Abdomino-pelvic hernias Paraduodenal e right (fossa of Waldeyer) Paraduodenal e left (fossa of Landzert) C C C C C Transmesenteric C Table Figure Coronal CT demonstrating small bowel obstruction SURGERY 31:11 Foramen of Winslow Bowel through a defect in right mesocolon into fossa of Waldeyer inferior to transverse segment of duodenum Most common Cluster of small bowel between pancreatic body/tail and stomach, above and to the left of the ligament of Treitz Inferior displacement of the duodenojejunal junction and transverse colon Abnormal location of bowel loops in lesser sac or high subhepatic space Hernias of bowel through congenital or acquired defect in mesentery or omentum 592 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY engorged mesenteric vessels radiating from the twisted bowel which is highly evocative of volvulus (Figure 7) Similar to SBO, CT is useful in diagnosing, delineating aetiology, level, degree and complications of obstruction LBO is diagnosed when there is faecal/gas filled large bowel proximal to a defined transition point with large bowel diameter exceeding 5.5 cm or caecum diameter greater than 10 cm Physiological contraction may mimic a transition point Features supporting physiological contraction include comparable bowel calibre proximal and distal, normal luminal wall thickness and absence of peri-enteric stranding.13 use as a means of relieving partial obstruction can be considered In those with a short luminal obstruction, a combined procedure of endoluminal self-expanding metallic stenting by both endoscopists and interventional radiologists may provide symptomatic relief both as a palliative measure or as a bridging procedure to definitive surgery Curved reformatted images are particularly useful in determining stent size Tumour ingrowth in and around the stent may result in recurrent obstruction requiring repeat stenting Bowel ischaemia Formerly, bowel ischaemia was diagnosed by direct catheter angiography but this has fallen out of favour given its invasive nature and lack of sensitivity to other causes of acute abdomen CT is currently the preferred imaging modality for the diagnosis and assessment of bowel ischaemia Local bowel ischaemia may be caused by arterial thromboembolism, venous occlusion or nonocclusive ischaemia Arterial and portal venous dual-phase CT imaging is commonly recommended with multiplanar reformats Arterial phase imaging is optimal for demonstrating mesenteric arterial patency whilst venous phase imaging better depicts mesenteric veins, bowel wall, and contrast enhancement of the solid abdominal viscera Direct CT signs of mesenteric ischaemia are filling defects/ occluded mesenteric arteries/veins Arterial thromboembolism usually lodges within 3e10 cm from the origin of the superior mesenteric artery, or just beyond the origin of the middle colic artery Secondary signs include bowel wall thickening which may be secondary to oedema, haemorrhage or superadded infection Bowel wall thickening is more prominent in venous thrombosis causing mesenteric ischaemic due to venous congestion and haemorrhage.15 Abnormal wall enhancement seen as a target sign or absent bowel wall enhancement is also a characteristic of mesenteric ischaemia Fluid filled luminal dilatation is also seen in cases of irreversible bowel ischaemia Additional features of generalized inflammation include mesenteric stranding and ascites which in the presence of small bowel ischaemia may signify transmural small bowel wall necrosis Pneumatosis cystoides intestinalis may appear as focal intramural gas locules or expansive rims of gas This is not pathognomonic of bowel ischaemia, recognized in conditions such as infection and inflammation When seen within portal venous gas, this is recognized as a poor prognostic indicator Radiological interventions in obstruction Management of bowel obstruction is dependent on underlying aetiology Pseudoobstruction is managed supportively whilst sigmoid volvulus are usually decompressed with flatus tube insertion and/or flexible sigmoidoscopy Patients with adhesional small bowel obstruction are difficult to evaluate and manage Water-soluble contrast medium, most commonly gastrografin, has been evaluated as a therapeutic option in those not requiring urgent surgical intervention Gastrografin is an ionic, hyperosmolar contrast agent, approximately six times the osmolarity of extracellular fluid Its proposed therapeutic effect relates to shifting of fluid into the bowel lumen and increasing the pressure gradient across an obstructive lesion The bowel content is thus diluted and allows easier passage of bowel content through the narrowed lumen.14 Dilute water-soluble enema in LBO has historically been used as a way of delineating the site of obstruction, although extracolonic manifestations are not readily appreciable Concurrent Radiological interventions in mesenteric ischaemia Surgery is traditionally the treatment of choice especially in the case of peritonitis and likely need for bowel resection Primary endovascular therapy may be considered in the setting of early patient identification in the absence of peritoneal signs Treatment includes aspiration embolectomy, local catheter-directed lysis, mechanical thrombectomy, or direct antegrade vascular stenting Secondary laparotomy may still be required in cases of failure, delayed bowel necrosis or development of abdominal compartment syndrome Gastrointestinal haemorrhage CT is the preferred investigation in those with suspected gastrointestinal haemorrhage helping identify patients who need direct catheter embolization to those with alternate diagnoses and subsequent alternate management pathways Figure Coronal CT demonstrating whirl-like configuration of the mesenteric vessels in volvulus SURGERY 31:11 593 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY Triple-phase imaging consisting of an unenhanced, arterial and portal venous phase acquisitions are commonly employed The unenhanced study aids visualization of luminal blood which appears as hyperdense fluid It also serves as a reference for the post-contrast study to assess for areas of enhancement and correctly identify calcification which can be mistaken for contrast if arterial phase imaging is performed alone Active arterial haemorrhage is seen as contrast blush arising close to bowel wall into high density fluid filled bowel lumen CT angiographic extravasation may appear as linear, jetlike, swirled or pooled configuration Bleeding rates of 0.5e1 ml/minute have traditionally been considered necessary in order to demonstrate active haemorrhage In essence, high-attenuation material detected within bowel lumen on post-contrast imaging not visualized on the unenhanced study is likely to represent acute haemorrhage Portal venous phase imaging is useful for assessing any venous engorgement, haemorrhage and is more commonly used in evaluating solid organ enhancement Radiological interventions in gastrointestinal haemorrhage Direct catheter angiography is considered more sensitive in depicting smaller volumes of active haemorrhage, 0.5 ml/minute when selective angiography is performed Extravasation of contrast depicts a breach in arterial wall integrity allowing contrast to flow freely from the vessel into bowel lumen thus outlining bowel folds/haustra Indirect signs of gastrointestinal haemorrhage include detection of pseudoaneurysm, arteriovenous fistula, neovascularity and hyperaemia Common mimics include digital subtraction misregistration from bowel/respiratory movement and hypervascular bowel mucosa Transcatheter angiography allows immediate subsequent treatment following identification of the bleeding site Embolization within the setting of gastrointestinal haemorrhage relies on careful selective reduction in arterial inflow whilst maintaining collateral arterial supply The goal of this is to reduce arterial inflow to allow haemostasis whilst maintaining vascularization to prevent bowel ischaemic/infarction Optimal treatment relies on superselective arterial catheterization of the feeding vessel, reducing non-target embolization A variety of embolic material can be used including gelatin sponge, particulate agents such as polyvinyl alcohol and microcoils.16 Figure Coronal CT demonstrating mid-ureteric calculus with right hydronephrosis On US, renal calculi appear as echogenic foci within the collecting systems with posterior acoustic shadowing Colour Doppler imaging demonstrates the typical twinkling artefact near the calculus Complications such as pelvicalyceal obstruction/ hydronephrosis, pyelonephritis and peri-nephric abscess formation are also well delineated Ureteric calculi are however less well visualized although proximal obstruction may be indicative Scanning is best performed with a full bladder allowing optimal visualization of bladder and vesicoureteric junction calculi Demonstration of ureteric jets on Doppler helps exclude complete urinary obstruction Abdominal radiography is often used in the acute setting but is often insufficient to confidently establish and exclude concurrent diagnoses In our institute, it is more commonly used as a method of stone follow-up Renal colic and obstructed urinary system Unenhanced CT is the modality of choice with US reserved for cases when patient susceptibility to ionizing radiation is of overriding concern Diagnosis is dependent on the presence of renal/ureteric calculi seen as hyperdense foci on CT (Figure 8) Their size, location and density are all important in guiding management Secondary signs of obstruction include a dilated proximal collecting system (hydroureter/hydronephrosis) and peri-ureteric/-nephric stranding The latter may also be representative of a concomitant infective process Intravenous contrast allows assessment of nephrographic asymmetry but may potentially obscure smaller intrarenal stones.17 Delayed excretory imaging, with maximal contrast opacification of the collecting system aids assessment of potential intraluminal filling defects such as neoplasia and also eases visualization of the ureteric pathway which can be problematic in thin patients SURGERY 31:11 Radiological interventions in an obstructed urinary system Percutaneous nephrostomy is the technique of percutaneous drain insertion into the pelvicalyceal system This can be performed under local anaesthetic using a combination of ultrasound and fluoroscopic guidance Decompression of the renal collecting system in the acute setting is urgently indicated in the case of an infected obstructed system.18 Urinary obstruction in the presence of renal dysfunction is an acute indication but not emergent indication Hydronephrosis in itself, is not necessarily an indication for nephrostomy insertion as this does not automatically indicate obstruction and can be physiological In the acute setting, nephrostomy insertion is often employed as a stabilizing treatment allowing further medical management Adjunctive treatment such as antegrade ureteric double-J stent insertion is best delayed until resolution of sepsis as 594 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY perirenal and pararenal spaces Active contrast extravasation is considered the most direct sign of rupture whilst discontinuity of the arterial wall may aid identification of the site of rupture Radiological interventions in AAA rupture Endovascular aneurysm repair (EVAR) is now a widely accepted form of treatment over open aortic repair Availability is dependent on local expertise and often a joint enterprise between vascular surgeons and interventional radiologists The diagnosing arterial phase CT relays important anatomical factors in guiding endovascular treatment such as suitability of proximal and distal landing zones, length and angulation of aneurysm neck, endograft sizing, volume of mural thrombus and relation to visceral vessels These factors need to be appropriately addressed to ensure successful deployment of an appropriate endograft body and their extension limbs into the common iliac vessels via common femoral access sheaths Otherwise, inadequate exclusion of the aneurysm sac may occur with resulting problematic endoleaks and continued systemic arterial pressurization of the aneurysm sac (Figure 10) Figure Axial CT of abdominal aortic aneurysm rupture with left peri- and pararenal haematoma interventional catheter manipulation during the acute infective episode predisposes the patient to a septic shower Conclusion Imaging plays an ever expanding role in diagnosing and guiding patient management Choice of imaging modality and subtle variations in scanning protocols is directed by the clinical question posed It is imperative to understand the advantages and limitations of each technique to ensure maximal evaluation whilst minimizing patient risk Subsequent identification of patients amenable to radiological intervention is also imperative to ensure optimal patient outcome A Abdominal aortic aneurysm (AAA) Abdominal aortic aneurysm is irreversible dilatation of the abdominal aorta more than 1.5 times the expected normal diameter Aortic rupture is a surgical emergency and rapid imaging is required for both diagnosis and in guiding treatment For this, arterial phase post-contrast CT is the imaging modality of choice given its availability and speed (Figure 9) The most common CT finding is retroperitoneal haemorrhage which appears as hyperattenuating fluid This commonly involves multiple retroperitoneal compartments including the REFERENCES Maturen KE, Wasnik AP, Kamaya A, et al Ultrasound imaging of bowel pathology: technique and keys to diagnosis in the acute abdomen AJR Am J Roentgenol 2011; 197: 1067e75 Singh A, Danrad R, Hahn PF, Blake MA, Mueller PR, Novelline RA MR imaging of the acute abdomen and pelvis: acute appendicitis and beyond Radiographics 2007; 27: 1419e31 Puylaert JB Acute appendicitis: US evaluation using graded compression Radiology 1986; 158: 355e60 Vijayaraghavan G, Kurup D, Singh A Imaging of acute abdomen and pelvis: common acute pathologies Semin Roentgenol 2009; 44: 221e7 Brown MA Imaging acute appendicitis Semin Ultrasound CT MR 2008; 29: 293e307 Tsuboi M, Takase K, Kaneda I, et al Perforated and nonperforated appendicitis: defect in enhancing appendiceal wall e depiction with multi-detector row CT Radiology 2008; 246: 142e7 Akhan O, Akinci D, Ozmen MN Percutaneous cholecystostomy Eur J Radiol 2002 Sep; 43: 229e36 Stoker J, van Randen A, Lameris W, Boermeester MA Imaging patients with acute abdominal pain Radiology 2009; 253: 31e46 Hinchey E, Schaal PG, Richards GK Treatment of perforated diverticular disease of the colon Adv Surg 1978; 12: 85e109 10 Musson RE, Bickle I, Vijay RKP Gas patterns on plain abdominal radiographs: a pictorial review Postgrad Med J 2011; 87: 274e87 Figure 10 Coronal CT of proximal endoleak following endovascular aneurysm repair of abdominal aortic aneurysm SURGERY 31:11 595 Ó 2013 Elsevier Ltd All rights reserved EMERGENCY SURGERY 11 Lazarus DE, Slywotsky C, Bennett GL, Megibow AJ, Macari M Frequency and relevance of the “small-bowel feces” sign on CT in patients with small-bowel obstruction AJR Am J Roentgenol 2004; 183: 1361e6 12 Petrovic B, Nikolaidis P, Hammond NA, Grant TH, Miller FH Identification of adhesions on CT in small-bowel obstruction Emerg Radiol 2006; 12: 88e93 13 Godfrey EM, Addley HC, Shaw AS The use of computed tomography in the detection and characterisation of large bowel obstruction N Z Med J 2009; 122: 57e73 14 Di Saverio S, Catena F, Ansaloni L, Gabioli M, Valentino M, Pinna AD Water-soluble contrast medium (gastrografin) value in adhesive small 15 16 17 18 intestine obstruction (ASIO): a prospective, randomized, controlled, clinical trial World J Surg 2008; 32: 2293e304 Kaewlai R, Kurup D, Singh A Imaging of abdomen and pelvis: uncommon acute pathologies Semin Roentgenol 2009; 44: 228e36 Walker TG, Salazar GM, Waltman AC Angiographic evaluation and management of acute gastrointestinal haemorrhage World J Gastroenterol 2012; 18: 1191e201 Karam AR, Birjawi GA, Sidani CA, Haddad MC Alternative diagnoses of acute appendicitis on helical CT with intravenous and rectal contrast Clin Imaging 2007; 31: 77e86 Saad WEA, Moorthy M, Ginat D Percutaneous nephrostomy: native and transplanted kidneys Tech Vasc Interv Radiol 2009; 12: 172e92 Your Comprehensive Guide To Vascular and Endovascular Surgery! Vascular and Endovascular Surgery, 8th Edition Master everything you need to know for certification, recertification, and practice From foundational concepts to the latest developments in the field, Dr Wesley Moore and a team of international experts prepare you to succeed, using an easyto-read, user-friendly format and hundreds of review questions to promote efficient and effective study • Get up to speed with the most recent practices and techniques in vascular diagnosis, peripheral arterial disease and many more with 16 brand new chapters important role of endovascular procedures • Visualise key techniques and anatomy thanks to hundreds of easy-to-follow illustrations, including line drawings, CT scans, angiograms, arteriograms, and photographs ISBN: 9781455746019 February 2013 As a subscriber to Surgery, you can save 20% on this title and all Elsevier books Save 20% on your copy today! RRP £142.00 Use discount code: 52121 at checkout to apply your discount SURGERY 31:11 596 Ó 2013 Elsevier Ltd All rights reserved MCQS Test yourself MCQ and extended matching The MCQ and extended matching section in Surgery is designed to test your knowledge of selected topics in this issue of the journal Michael G Wyatt MSc MD FRCS FRCSEd (ad hom) Consultant Surgeon, Freeman Hospital, Newcastle upon Tyne, UK Honorary Reader, Newcastle University, Clinical Editor, SURGERY, Honorary Secretary, The Vascular Society of Great Britain and Ireland, and Member of the Court of Examiners for the Intercollegiate MRCS For questions 1e4, select the statements which are true and which are false The correct answers are given below E Imaging and radiological interventions for the acute abdomen Recognition and management of intraabdominal hypertension and the abdominal compartment syndrome When considering imaging and terventions for the acute abdomen When considering patients with the abdominal compartment syndrome A B C radiological in- A Abnormally high intra-abdominal pressures (IAP) can lead to multi-system organ dysfunction due to a combination of direct pressure effects and the release of endotoxins which can be life threatening Magnetic resonance imaging (MRI) is now the imaging method of choice in the preliminary investigation of the acute abdomen B Early signs of abdominal compartment syndrome include oliguria, acidosis, hypotension, rising ventilatory pressures and hypoxia Ultrasonic visualization of the appendix is commonly best appreciated with a linear high-frequency transducer using the graded compression technique C Plain abdominal radiography can diagnose cholecystitis, with a sensitivity and specificity of 90% D Ultrasound is currently the preferred imaging modality for the diagnosis and assessment of bowel ischaemia E Direct catheter angiography is considered more sensitive in depicting smaller volumes of active haemorrhage, 0.5 ml/minute when selective angiography is performed Patients with intra-abdominal hypertension (IAP 12e20 mmHg) should only undergo non-surgical optimization if they have no signs of compartment syndrome D An ‘open-abdomen’ is poorly tolerated and carries significant risk of infective complications E Recently developed topical negative pressure dressings are not effective in preventing adhesions, and preserving fascial edges The management of bariatric surgery complications For patients presenting with complications following bariatric surgery Control of major haemorrhage and damage control surgery A Only around 5% of gastric bands will require further surgery at some point B The risk of developing an obstruction following a laparoscopic Roux en-Y gastric bypass may be as high as 20%, with the mean time to presentation being approximately year C Patients undergoing bariatric surgery commonly develop gallstones due to changes in the cholesterol content of bile and in the motility of the gallbladder When considering the control of major haemorrhage and damage control surgery A Permissive hypotension aims at restricting fluid resuscitation until control of bleeding is achieved Major haemorrhage is life-threatening bleeding which accounts for blood loss greater than 40% (2 litres) of total circulating volume B The isthmus of the aorta is subject to significant stress during impact in road traffic accidents D C Primary blast injuries are a form of blunt trauma and the lungs and hollow viscera are most sensitive to the barotrauma produced The most significant early complications following laparoscopic sleeve gastrectomy are haemorrhage and leakage from the proximal staple line E D Although the incidence of iatrogenic injury to major vasculature is rare in laparoscopic surgery, it can result in catastrophic haemorrhage Most experienced bariatric surgeons will choose to relaparoscope any patient who is ‘not quite right’ after their operation, as radiological imaging of these patients can be difficult to undertake and inconclusive see next page SURGERY 31:11 597 MCQS Questions cont Lower gastrointestinal emergencies and appendicitis Theme: lower appendicitis A gastrointestinal emergencies and Its acute presentation is usually with an associated complication including inflammation, abscess, perforation or fistulation C Colorectal cancer is the most common cause, accounting for 50% of cases D Both Crohn’s disease and ulcerative colitis (UC) may present in this manner, but it is more frequent in UC E Is sometimes assessed using the Alvarado scoring system F Emergency presentation is associated with a poorer prognosis, with a higher incidence of lymph node metastasis, and a lower 5-year cancer-related survival G May present as an emergency as toxic mega colon, massive haemorrhage, perforation or obstruction H Is more common in the elderly, in those with chronic neurological disorders (stroke, Parkinson’s, multiple sclerosis), patients with mental illness and the institutionalized Large bowel obstruction Colorectal cancer Volvulus Acute colonic pseudo-obstruction Appendicitis SURGERY 31:11 Inflammatory bowel disease Acute toxic dilatation A, B All B, E C, D, E 1C, 2F, 3H, 4A, 5E, 6B, 7G, 8D Answers to incorrect statements Question C All patients with intra-abdominal hypertension (IAP 12e20 mmHg) should initially undergo non-surgical optimization D An ‘open-abdomen’ is surprisingly well tolerated and carries minimal risk of further morbidity e in particular the risk of infective complications is low E More recently, several topical negative pressure dressings have been developed which are effective at preventing adhesions, maintaining abdominal domain and preserving fascial edges Question A Magnetic resonance imaging (MRI) is not commonly used in preliminary investigation of the acute abdomen C Radiography is of limited use in diagnosing cholecystitis, with only 15% of gallstones containing calcium visible on plain X-rays D CT is currently the preferred imaging modality for the diagnosis and assessment of bowel ischaemia Question When considering the lower gastrointestinal emergencies and appendicitis conditions listed below, select the single most likely true statement from the list above Each option may be used only once, more than once or not at all Acute diverticulitis Answers Presents with all the symptoms, signs and radiological findings of large bowel obstruction, but without mechanical cause B A Around 20% of gastric bands will require further surgery at some point B The risk of developing an obstruction following a laparoscopic Roux en-Y gastric bypass may be as high as 5%, with the mean time to presentation being approximately year 598 .. .General Surgery: Prepare for the MRCS Key articles from the Surgery Journal Series Editor W E G Thomas MS FRCS FSACS(Hon) ... better access In the latter, so named from the Greek to ‘cut for the stone’, the patient is supine with the buttocks placed at the lower break in the table and the legs flexed at the hips and knees,... (with the xiphisternal junction at the summit of the arch) The lateral boundary on either side is, arbitrarily, the mid-axillary line (between the lateral part of the costal margin and the summit