Upper Gastrointestinal Surgery - part 1 ppt

It is aided in these functions by the upper and lower oesophageal sphincters sited at its proximal and distal ends.. Anatomical Relationships of the Oesophagus The oesophagus can be arti

Springer Specialist Surgery Series

Transplantation Surgery, edited by Hakim & Danovitch, 2001

Neurosurgery: Principles and Practice, edited by Moore & Newell, 2004

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John W L Fielding and Michael T Hallissey

Upper Gastrointestinal Surgery

Series Editor: John Lumley

British Library Cataloguing in Publication Data

Upper gastrointestinal surgery – (Springer specialist surgery series)

1 Digestive organs – Surgery

I Fielding, J W L (John William Lewis) II Hallissey, Michael T.

617.4 ′3

ISBN 1852336072

Library of Congress Cataloging-in-Publication Data

Upper gastrointestinal surgery/[edited by] John W L Fielding and Michael T Hallissey.

p.cm – (Springer specialist surgery series)

Includes bibliographical references and index.

ISBN 1-85233-607-2 (h/c: alk paper)

1 Digestive organs – Surgery 2 Gastrointestinal system – Surgery 3 Liver – Surgery

4 Upper Gastrointestinal Surgery I Fielding, J W L II Hallissey, Michael T III Series.

[DNLM: 1 Digestive System Surgical Procedures 2 Biliary Tract Diseases – surgery

3 Gastrointestinal Diseases – surgery 4 Liver Diseases – surgery WI 900 H529 2004]

RD540.5.H47 2004

617.4 ′3–dc22 2004042555

Apart from any fair dealing for the purposes of research or private study, or criticism or review, as

permit-ted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or

transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the

case of reprographic reproduction in accordance with the terms of licences issued by the Copyright Licensing

Agency Enquiries concerning reproduction outside those terms should be sent to the publishers.

ISBN 1-85233-607-2 Springer-Verlag London Berlin Heidelberg

Springer-Verlag is part of Springer Science+Business Media

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© Springer-Verlag London Limited 2005

The use of registered names, trademarks, etc in this publication does not imply, even in the absence of a

specific statement, that such names are exempt from the relevant laws and regulations and therefore free for

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Training and assessment have followed these trends, but often in a disorganisedfashion, without due concern for curricular development and adequate integration ofbasic and advanced educational requirements

Regardless of these arguments, all surgeons working in a field require appropriate

skills and the best available information to deliver optimal care; the Springer Specialist

Surgical Series addresses these needs.

This volume considers the upper gastrointestinal tract, from the oesophagus to thesmall bowel The liver, biliary tree and pancreas make up a separate volume, but the spleen, that orphan of the upper abdomen, is expertly covered, providing the readerwith an added bonus

The editors have skilfully chosen topics that provide a comprehensive cover of thefield, while emphasizing the growing edges and future direction of their speciality Theyhave brought together a unique group of authors, each a recognized expert in the field.The resultant text is compelling and essential reading for all those involved in the management of disease of the upper alimentary tract, whatever their discipline

Foreword

by Professor John Lumley v

Contributors ix

1. The Anatomy and Physiology of the Oesophagus

Peter J Lamb and S Michael Griffin 1

2. The Anatomy and Physiology of the Stomach

Ian R Daniels and William H Allum 17

3. The Anatomy and Physiology of the Small Bowel

6. Benign Disease of the Oesophagus

Stephen E.A Attwood and Christopher J Lewis 69

7. Benign Diseases of the Stomach

Robert C Mason 91

8. Benign Disease of the Small Bowel

Ling S Wong, Emmanuel A Agaba and Michael R.B Keighley 101

9. Benign Disease of the Diaphragm

Juliet E King and Pala B Rajesh 117

10. Benign Diseases of the Spleen

Refaat B Kamel 127

11. Epithelial Neoplasms of the Oesophagus

Derek Alderson and Jonathan H Vickers 155

12. Epithelial Neoplasms of the Stomach

13. Cancer at the Gastro-oesophageal Junction (Epidemiology)

Gill M Lawrence 181

14. Neoplasms of the Small Bowel

Aviram Nissan and Martin S Karpeh 193

15. Stromal Upper GI Tract Neoplasms

Stephan T Samel and Stefan Post 207

16. Neoplasms of the Spleen

Mark G Coleman and Michael R Thompson 221

17. Lymphomas

Mark Deakin, A Murray Brunt, Mark Stephens and Richard C Chasty 231

18. Pathology of the Oesophagus and Stomach

Sukhvinder S Ghataura and David C Rowlands 241

19. Premalignant Lesions of the Oesophagus: Identification

to Management

Andrew Latchford and Janusz A.Z Jankowski 259

20. High Risk Lesions in the Stomach

Marc C Winslet and S Frances Hughes 271

21. Upper GI Endoscopy

Michael T Hallissey 279

22. Imaging in GI Surgery

Julie F C Olliff and Peter J Guest 287

23. High Risk Lesions in the Oesophagus and Nuclear Medicine

Andrew Phillip Chilton and Janusz A Z Jankowski 307

24. Surgical Resection for Oesophageal Cancer: Role of Extended

Lymphadenectomy

Hubert J Stein, Jörg Theisen and Jörg-Rüdiger Siewert 317

25. Surgical Resection of the Stomach with Lymph Node Dissection

Mitsuru Sasako, Takeo Fukagawa, Hitoshi Katai and Takeshi Sano 335

26. Chemotherapy of Upper GI Neoplasms: Proven/Unproven

Niall C Tebbutt and David Cunningham 349

27. Radiotherapy in Upper GI Tract Neoplasms

M Suhail Anwar, Ju Ian Geh and David Spooner 359

Index 369

CONTENTS

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Emmanuel A Agaba MB BS, FRCSDepartment of Surgery

Walsgrave HospitalUniversity Hospitals Coventry andWarwickshire NHS Trust

CoventryUKDerek Alderson MB BS, MD, FRCSDivision of Surgery

University Department of SurgeryBristol Royal Infirmary

BristolUKWilliam H Allum BSc, MD, FRCSDepartment of Surgery

Royal Marsden Hospital NHS TrustSutton

SurreyUK

M Suhail Anwar BSc, MBBS, MRCP, FRCR

Department of OncologyCancer Centre

Queen Elizabeth HospitalBirmingham

UKStephen E A Attwood MD, MB BCh, FRCSI, FRCS

Regional Laparoscopic UnitNorthumbria Healthcare TrustNorth Tyneside

NorthumberlandUK

A Murray Brunt MB BS, MRCP, FRCRDepartment of Oncology

University Hospital of North StaffordshireStoke-on-Trent

UK

Richard C Chasty MB BS, MD, FRCP,MRCPath

Department of HaematologyUniversity Hospital of North StaffordshireStoke-on-Trent

UKAndrew Phillip Chilton MRCPDepartment of GastroenterologyKettering General HospitalKettering

NorthampshireUK

Mark G Coleman MD, FRCSThe Colorectal Unit

Derriford HospitalPlymouthUKDavid Cunningham MD, FRCPDepartment of MedicineThe Royal Marsden HospitalSutton, Surrey

UKIan R Daniels MB, FRCSDepartment of SurgeryPelican CentreNorth Hampshire HospitalBasingstoke

Hampshire, UKMark Deakin ChM, FRCS, FRCSEDepartment of Surgery

University Hospital of North StaffordshireStoke on Trent

UKJohn W L Fielding MD, FRCSDepartment of SurgeryQueen Elizabeth HospitalBirmingham

Takeo Fukagawa MD, PhD

Department of Surgical Oncology

National Cancer Centre Hospital

Upper GI Surgical Unit

Queen Elizabeth Hospital

Birmingham

UK

S Michael Griffin MB BS, MD, FRCS

Northern Oesophago-Gastric Unit

Royal Victoria Infirmary

Newcastle upon Tyne

UK

Peter J Guest MRCP, FRCR

Department of Imaging

University Hospital Birmingham

Queen Elizabeth Hospital

George R Harrison BSc, MB BS, FFARCS

Department of Pain Management

Selly Oak Hospital

University Department of Cancer Studiesand Molecular Medicine

Leicester Medical SchoolLeicester Royal InfirmaryLeicester

UKRefaat B Kamel MD, FICS, FACSDepartment of General SurgeryFaculty of Medicine

Ain-Shams UniversityInternational College of SurgeonsCairo

EgyptMartin S Karpeh MDThe State University of New YorkDivision of Surgical OncologyHealth Sciences CenterStony Brook, NYUSA

Hitoshi Katai MD, PhDDepartment of Surgical OncologyNational Cancer Centre HospitalTokyo

JapanMichael R.B Keighley MB BS, MS, FRCSDepartment of Surgery

University of BirminghamQueen Elizabeth HospitalBirmingham

UKJuliet E King BM, FRCSDepartment of Thoracic SurgeryBirmingham Heartlands HospitalBirmingham

UKPeter J Lamb MB BS, FRCSNorthern Oesophago-Gastric Cancer UnitRoyal Victoria Infirmary

Newcastle upon TyneUK

Andrew Latchford MB BS, BSc, MRCPDepartment of Gastroenterology

St Mark’s HospitalHarrow

MiddlessexUK

CONTRIBUTORS

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Gill M Lawrence PhDWest Midlands Cancer Intelligence UnitThe University of Birmingham

BirminghamChristopher J Lewis MB BCh, MRCSDepartment of Upper GI SurgeryHope Hospital

SalfordUKRobert C Mason BSc, MB ChB, MD, FRCSDepartment of Surgery

St Thomas’ HospitalLondon

UKPeter McCulloch MB ChB, MD, FRCSAcademic Unit of Surgery

University Hospital AintreeUniversity of LiverpoolLiverpool, UK

Aviram Nissan MDGastric and Mixed Tumor ServiceDepartment of Surgery

Memoral Sloan-Kettering Cancer CenterNew York, NY

USAJulie F.C Olliff MRCP, FRCRDepartment of ImagingUniversity Hospital BirminghamQueen Elizabeth HospitalBirmingham

UKStefan Post MDSurgery ClinicUniversity HospitalMannheimGermanyPala B Rajesh MB BS, FRCS, FETCSRegional Department of Thoracic SurgeryBirmingham Heartlands HospitalBirmingham

UKDavid C Rowlands FRCPathDepartment of HistopathologyThe Medical School

University of BirminghamQueen Elizabeth Medical CentreBirmingham

UK

Stephan T Samel MDGroup Practice Dres Schiller / SamelGöttingen

GermanyTakeshi Sano MD, PhDDepartment of Surgical OncologyNational Cancer Centre HospitalTokyo

JapanMitsuru Sasako MD, PhDDepartment of Surgical OncologyNational Cancer Center HospitalTokyo

JapanJörg-Rüdiger Siewert MD, FACS, FRCSChiurg Klinik und Poliklinik

Klinikum rechts der Isar der TU MünchenMünchen

GermanyDavid Spooner MB ChB, BSc, FRCP, MRCP,FRCR

Department of OncologyCancer Centre

Queen Elizabeth HospitalBirmingham

UKHubert J Stein MDChirurgische Klinik und PoliklinikKlinikum rechts der Isar der TU MünchenMünchen

GermanyMark Stephens MB BCh, MRCPathDepartment of HistopathologyCentral Pathology LaboratoryStoke-on-Trent

UKNiall C Tebbutt BM BCh, PhD, MRCP,FRACP

Department of OncologyAustin Hospital

Heidelberg, VictoriaAustralia

Jörg Theisen MDChirurgische Klinik und PoliklinikKlinikum rechts der Isar der TU MünchenMünchen

Weston General Hospital

Weston Super Mare

North Somerset

UK

Marc C Winslet MS, FRCSDepartment of SurgeryRoyal Free & University College MedicalSchool

The Royal Free HospitalLondon

UKLing S Wong MD, FRCSDepartment of SurgeryWalsgrave HospitalUniversity Hospitals Coventry andWarwickshire NHS Trust

CoventryUK

CONTRIBUTORS

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● To develop an understanding of the

surgical anatomy of the oesophagus

● To establish the normal physiology and

control of swallowing

● To determine the structure and function

of the antireflux barrier

● To evaluate the effect of surgery on the

function of the oesophagus

Introduction

The oesophagus is a muscular tube connecting

the pharynx to the stomach and measuring

25–30 cm in the adult Its primary function is as

a conduit for the passage of swallowed food and

fluid, which it propels by antegrade peristaltic

contraction It also serves to prevent the reflux

of gastric contents whilst allowing

regurgita-tion, vomiting and belching to take place It is

aided in these functions by the upper and lower

oesophageal sphincters sited at its proximal and

distal ends Any impairment of oesophageal

function can lead to the debilitating symptoms

of dysphagia, gastro-oesophageal reflux or

oesophageal pain

The apparently simple basic structure of

the oesophagus belies both its physiological

importance and the dangers associated with

surgical intervention As a consequence of its

location deep within the thorax and abdomen,

a close anatomical relationship to major tures throughout its course and a marginalblood supply, the surgical exposure, resectionand reconstruction of the oesophagus arecomplex Despite advances in perioperativecare, oesophagectomy is still associated with thehighest mortality of any routinely performedelective surgical procedure [1]

struc-In order to understand the ogy of oesophageal disease and the rationale for its medical and surgical management a basic knowledge of oesophageal anatomy andphysiology is essential The embryologicaldevelopment of the oesophagus, its anatomicalstructure and relationships, the physiology of its major functions and the effect that surgeryhas on them will all be considered in thischapter

pathophysiol-Embryology

The embryonic development of the oesophaguslike that of all major organ systems takes placebetween the fourth and eighth weeks of gesta-tion as the three germ layers differentiate into specific tissues During the fourth week, asthe embryo folds, part of the dorsal yolk sac isincorporated into the developing head as theforegut (Figure 1.1a) This ultimately developsinto not only the oesophagus, stomach and duo-denum but also the pharynx, lower respiratorysystem, liver, pancreas and biliary tree

Early in the fourth week the laryngotracheal

diverticulum develops in the midline of the

ventral wall of the foregut This extends caudally

and becomes separated from the foregut by

growth of the tracheo-oesophageal folds, which

fuse to form the tracheo-oesophageal septum

(Figure 1.1b and c) This creates the

laryngotra-cheal tube (ultimately the larynx, trachea,

bronchi and lungs) and dorsally the oesophagus

[2] Failure of this separation can occur due to

a shortage of proliferating endothelial cells in

the tracheo-oesophageal folds This results in a

tracheo-oesophageal fistula, which is commonlyassociated with oesophageal atresia Completefailure to close the tracheo-oesophageal septum

is much less common and results in a oesophageal cleft Normally the oesophaguslengthens rapidly as a result of cranial bodygrowth (with descent of the heart and lungs) toreach its final relative length by the seventhweek During elongation the lumen is tem-porarily obliterated by proliferation of endo-dermal cells and failure to recanalise results inoesophageal atresia

laryngo-Oesophageal atresia is present in mately 1 in 3000 live births In 85% of casesthere is proximal oesophageal atresia with afistula between the distal oesophagus and therespiratory tract, usually the trachea Lesscommon combinations are oesophageal atresiawithout a fistula (10%), a fistula without atresia(2%) and a fistula between the upper oesopha-gus and trachea (1%) Because of the embryonictime period during which these failures takeplace 50% of oesophageal malformations areassociated with major defects in other organsystems In 25% these are cardiovascular, most commonly a patent ductus arteriosus, although musculoskeletal and other gastroin-testinal defects, classically an imperforate anus,are also seen

approxi-The artery of the foregut is the coeliac axisand whilst this supplies the distal oesophagus,more proximally it takes branches directly fromthe developing aorta During the developmentalsequence described, the epithelium and glands

of the oesophagus are derived from endoderm.The striated skeletal muscle of the proximalthird of the oesophagus is derived from mes-enchyme in the caudal branchial arches whilstthe smooth muscle of the more distal oesopha-gus develops from surrounding splanchnic mes-enchyme Even in the fetus the oesophagus is ofvital functional importance, allowing swallowedamniotic fluid to pass to the intestines forabsorption and placental transfer to maternalblood

Adult Oesophageal Anatomy

The oesophagus is a muscular tube protected atits ends by the upper and lower oesophageal

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Aorta

Coeliac axis Midgut

Hindgut

(ii) Pharynx Oesophagus

FFigure 1.1 a–c The embryological development of the

oesophagus a Sagittal section of a 4-week-old embryo

b–c The development of the tracheo-oesophageal septum and

separation of the oesophagus and laryngotracheal tube

sphincters It commences as a continuation of

the pharynx at the lower border of the

cricopha-ryngeus muscle, at the level of the sixth cervical

vertebra (C6) The surface marking for this

point is the lower border of the cricoid cartilage

It enters the chest at the level of the

supraster-nal notch and descends through the superior

and posterior mediastinum along the front

of the vertebral column It passes though the

oesophageal hiatus in the diaphragm at the

level of the tenth thoracic vertebra to end at

the gastro-oesophageal junction The surface

marking for this point is the left seventh costal

cartilage The oesophagus measures 25–30 cm

in length although this varies according to the

height of the individual and in particular the

suprasternal–xiphoid distance

Anatomical Relationships of the

Oesophagus

The oesophagus can be artificially divided from

proximal to distal into cervical, thoracic and

abdominal segments [3] (Figure 1.2)

Cervical Oesophagus

This begins at the lower border of the cricoidcartilage (C6) and ends at the level of the tho-racic inlet or jugular notch (T1) It lies betweenthe trachea anteriorly and the prevertebral layer

of cervical fascia posteriorly, deviating slightly

to the left at the level of the thyroid gland beforereturning to enter the thorax in the midline(Figure 1.3) The recurrent laryngeal nerves run

in a caudal direction either side of the agus in the tracheo-oesophageal groove Theyinnervate the laryngeal muscles and surgicaltrauma to the nerve at this point results in anipsilateral vocal cord palsy More laterally lie thelobes of the thyroid gland with the inferiorthyroid artery and the carotid sheath contain-ing the carotid vessels and the vagus nerve

oesoph-Thoracic Oesophagus

The upper thoracic oesophagus extends thelength of the superior mediastinum between the thoracic inlet and the level of the carina (T5).The middle and lower thoracic oesophagus lies

THE ANATOMY AND PHYSIOLOGY OF THE OESOPHAGUS

Pulmonary artery Oesophagus

Diaphragm

Upper thoracic oesophagus

Middle thoracic oesophagus

Abdominal oesophagus

Lower thoracic oesophagus Lower

Oesophagus

Figure 1.2 The divisions and anatomical relations of the oesophagus

in the posterior mediastinum subdivided by the

midpoint between the tracheal bifurcation and

the oesophagogastric junction (Figure 1.2)

In the superior mediastinum the upper

thor-acic oesophagus maintains close contact with

the left mediastinal pleura and posteriorly with

the prevertebral fascia At this level the

oesoph-agus is indented by the arch of the aorta on its

left side and crossed by the azygos vein on

its right side As it descends into the posterior

mediastinum it is also crossed anteriorly and

indented by the left main bronchus and crossed

by the right pulmonary artery (Figure 1.2)

Below this level the pericardium and left atrium

lie anterior to the oesophagus

The middle thoracic oesophagus deviates to

the right, coming into close apposition with the

right mediastinal pleura, which covers its right

side and posterior aspect It also moves forward

with a concavity more marked than the

verte-bral column, allowing the azygos vein, the

tho-racic duct, the right upper five intercostal

arteries and the descending aorta to all pass

posteriorly during its course

The azygos vein originates in the upper

abdomen and enters the mediastinum via the

aortic opening in the diaphragm It ascends

along the right posterolateral aspect of the

oesophagus before arching over the root of

the right lung to enter the superior vena cava

(Figure 1.2) Resection of this arch allows

improved surgical access to the oesophagus via

the right chest The thoracic duct originates in

the cisterna chyli anterior to the second lumbar

vertebra and passes through the diaphragmatic

hiatus on the right side of the aorta posterior to

the right crus It provides lymphatic drainage

for the lower body and the left half of the upper

body The duct lies on the right lateral aspect of

the descending thoracic aorta in the inferior

mediastinum It is here that the duct or its radicals may be inadvertently damaged duringmobilisation of the oesophagus, resulting in achylothorax [4] The duct then ascends, passingbehind the oesophagus to lie on its left side inthe superior mediastinum The oesophagus ini-tially lies to the right of the descending aorta butcrosses it during its descent to lie anterior and

on its left side as it approaches the diaphragm

Abdominal Oesophagus

The lower oesophagus comprises the lower racic, oesophagus together with the short intra-abdominal portion of oesophagus (Figure 1.2).The oesophageal opening in the diaphragm lies within fibres of the left crus inside a sling

tho-of fibres passing across from the right crus Atthis point the vagal trunks lie on the anteriorand posterior surface of the oesophagus having emerged from the oesophageal plexuses

on its lower surface The oesophageal branches

of the left gastric artery with associated veinsand lymphatics also accompany the oesoph-agus The intra-abdominal portion of theoesophagus extends from the diaphragm to the gastro-oesophageal junction It is covered

by peritoneum (the gastrophrenic ligament)and lies posterior to the left lobe of the liver

It is usually 1–2 cm in length although even

in the normal individual this varies according

to the muscle tone, degree of gastric distensionand respiration

Although essentially a midline structure,these deviations of the oesophagus to the left inthe neck, to the right in the posterior medi-astinum and left and anteriorly towards thediaphragmatic hiatus have important clinicalconsequences This course must be consideredcarefully when the surgical approach to the

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Oesophagus

Recurrent laryngeal nerve Carotid sheath

Thyroid Trachea

Comon carotid artery Interior jugular vein Vagus nerve

oesophagus is determined For optimum

expo-sure the cervical oesophagus should be

approached from the left side of the neck, the

thoracic oesophagus from the right side of

the thorax and the lower oesophagus and the

gastro-oesophageal junction from the abdomen

or by a left thoraco-abdominal approach [5]

Endoscopic Anatomy

These relations are also important when we

con-sider the endoscopic anatomy of the

oesopha-gus By consensus endoscopic landmarks are

identified by their distance in centimetres from

the incisor teeth, measured with the flexible

video-endoscope The narrowest point of the

oesophagus is its commencement at the level of

cricopharyngeus (upper oesophageal

sphinc-ter), 15 cm from the incisors Further

indenta-tions are caused by the aortic arch at 22 cm, the

left main bronchus at 27 cm and the diaphragm

at 38 cm All distances vary according to the

height of the individual An enlarged left atrium

may also indent the anterior aspect of the lower

oesophagus

The gastro-oesophageal junction is defined

endoscopically as the upper margin of the

prox-imal gastric folds On average this is at 37 cm in

females and 40 cm in males although it migrates

proximally in the case of a sliding hiatus hernia

The squamocolumnar junction is also visible

endoscopically as the Z-line and usually

coin-cides with the gastro-oesophageal junction,

although it may be more proximal in the

pres-ence of Barrett’s oesophagus where there is

columnarisation of the lower oesophagus [6]

Attachments of the Oesophagus

The oesophagus is held in loose areolar tissue in

the mediastinum, allowing sizable vertical

movement during respiration Within this are

slips of smooth muscle fibres tethering it to

neighbouring structures, notably the trachea,

left bronchus, pericardium and aorta The

major oesophageal attachment, however, is

dor-sally, the phreno-oesophageal ligament This

condensation of connective tissue is an

exten-sion of the diaphragmatic and thoracic fascia

Its upper and lower limbs tether the lower few

centimetres of the thoracic oesophagus and the

gastro-oesophageal junction to the aorta and

the diaphragmatic hiatus It is weak anteriorly

and laterally but the posterior aspect is strongand serves to maintain the intra-abdominalposition of the gastro-oesophageal junction andlower oesophageal sphincter Weakening of the phreno-oesophageal ligament allows theoesophagus to rise, resulting in a sliding type ofhiatus hernia The ligament also maintains the angle between the distal oesophagus and theproximal stomach (the angle of His), allowing amucosal fold of the greater curve aspect of thegastro-oesophageal junction to close against the lesser curvature The flap valve created mayhave a role in the antireflux mechanism of thegastro-oesophageal junction

Structure of the Oesophagus

Upper Oesophageal Sphincter (UOS)

This creates a zone of high pressure between thepharynx and the proximal oesophagus, whichrelaxes during swallowing and preventsaerophagia during respiration At this level hor-izontal fibres of the cricopharyngeus musclepass posteriorly from the cricoid bone to jointhe inferior pharyngeal constrictor and create acontinuous muscular band Posteriorly justproximal to cricopharyngeus there is a relativeweakness, Killian’s triangle, that is the origin of

a pharyngeal pouch

Body of the Oesophagus

Histologically this is made up of four layers:adventitia, muscle, submucosa and mucosa(Figure 1.4) In the mediastinum the oesopha-gus has no serosal covering and the dense con-nective tissue of the adventitia forms its outerlayer The muscular layer is composed of anouter longitudinal and an inner circular layer.Proximally, the longitudinal fibres originatefrom the dorsal aspect of the cricoid and thecricopharyngeus tendon to descend in a gentlespiral These longitudinal muscle fibres splitabove the gastro-oesophageal junction creating

a potential vertical weakness on the left terolateral aspect This is the most common site

pos-of a tear in the case pos-of spontaneous rupture pos-ofthe oesophagus (Boerhaave’s syndrome) Thecircular muscle layer is continuous proximallywith the inferior constrictor and the musclefibre arrangement is elliptical in nature This isdesigned for peristalsis, to propel food to thestomach and clear refluxed gastric contents

THE ANATOMY AND PHYSIOLOGY OF THE OESOPHAGUS

from the oesophagus The proximal 4–6 cm of

both layers of oesophageal muscle is striated

There is a mixture of striated and smooth

muscle below this to around 10–13 cm and the

lower half to one-third of the oesophagus

con-tains only smooth muscle [7]

The submucosal layer consists of elastin

fibres within a loose connective tissue and

allows distension of the oesophagus during

swallowing The absence of a serosal layer

makes oesophageal anastomosis technically

difficult and reliant upon the strength of the

submucosa It transmits abundant lymphatic

channels, blood vessels, and the submucosal

nerve plexus It also contains oesophageal

glands, which open into the lumen via a long

single duct These secrete mucus for bolus

lubri-cation, bicarbonate ions to neutralise refluxed

acid and growth factors that help to maintain

the integrity of the oesophageal epithelium

The oesophageal mucosa is a non-keratinisedstratified squamous epithelium with a base-ment membrane separating it from the under-lying lamina propria and muscularis mucosa(Figure 1.4) This changes close to the gastro-oesophageal junction to a columnar-linedgastric epithelium at the squamocolumnar junction In Barrett’s oesophagus columnarmetaplasia of the lower oesophagus occurs as aresponse to chronic acid and bile reflux charac-terised histologically by intestinal metaplasiaand the presence of goblet cells [8]

Lower Oesophageal Sphincter (LOS)

Although there is a functional high-pressurezone in the lower oesophagus, the presence of

an anatomical sphincter has been disputed.There is, however, an increase in the circularmuscle layer at this level and ultrastructural

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Myenteric plexus

Circular muscle Longitidinal muscle

Adventitia

Submucosa

Submucosal gland

Muscularis mucosae Stratified squcmous epithelium Mucosa Lamina propria

studies have demonstrated morphological

alter-ations in the muscle cells of this area

Blood Supply and Lymphatic

Drainage of the Oesophagus

Arterial Supply

The oesophagus receives a segmental blood

supply with extensive collaterals along its

course (Figure 1.5) In the neck and superior

mediastinum it is primarily supplied by vessels

from the inferior thyroid artery, a branch of

the subclavian artery Rarely these may be

supported by smaller vessels directly from the

common carotid, vertebral or subclavian

arter-ies In the posterior mediastinum the

oesopha-gus receives direct aortic branches These

short vessels must be carefully identified during

mobilisation of the oesophagus and ligated in

continuity to prevent avulsion from the aorta

They anastomose with bronchial arteries that

enter the oesophagus at the tracheal bifurcation,

and small branches from the intercostal

arter-ies The lower oesophagus receives its main

supply from ascending branches of the left

gastric artery, originating from the coeliac axis,

aided by the left inferior phrenic artery

Although the nutrient arteries to the

oesopha-gus are not end arteries, this segmental supply

must be carefully considered during surgical

reconstruction of the oesophagus to prevent

ischaemic complications

Venous Drainage

This commences along the length of the

oesophagus with the submucosal venous plexus,

which drains into an extrinsic plexus on the

oesophageal surface As with the arterial supply,

the precise venous drainage is variable From

the upper oesophagus it is via the inferior

thyroid veins to the brachiocephalic vein and in

the mediastinum it is via the azygos and

hemi-azygos systems that ultimately drain into the

superior vena cava However, from the lower

oesophagus it is via tributaries of the left gastric

vein, which empties into the portal vein

creat-ing a portosystemic anastomosis in the lower

oesophagus In the presence of portal venous

hypertension raised pressure is transmitted to

the submucosal plexus of the lower oesophagus,

creating fragile varicosities These oesophageal

varices are important clinically as a major cause

of massive upper gastrointestinal haemorrhage.The direct communication with both the sys-temic and portal systems may also be important

in the metastatic dissemination of oesophagealcarcinoma

Lymphatic Drainage

The lymphatic pathways draining the gus are complex and the presence of lymphat-ics within the mucosa makes it unique withinthe gastrointestinal tract These and extensivesubmucosal lymphatics form a complex inter-connecting network extending the length of theoesophagus, intermittently piercing the muscu-lar layers to drain into the para-oesophageal

oesopha-THE ANATOMY AND PHYSIOLOGY OF oesopha-THE OESOPHAGUS

102 103 100

112

105 101

107 106

109

8 9 1 10

Inferior thyroid artery

Trachea

Direct gortic branches

Left gastric artery

Splenic artery

Coeliac axis

Common hepatic artery

Figure 1.5 Arterial blood supply and lymphatic drainage of theoesophagus Cervical lymph nodes: 100, lateral cervical; 101,cervical para-oesophageal; 102, deep cervical; 103, supraclavic-ular Mediastinal lymph nodes: 105, upper para-oesophageal;

106, paratracheal; 107, carinal; 108, middle para-oesophageal;

109, left and right bronchial; 110, lower para-oesophageal;

112, posterior mediastinal Abdominal lymph nodes: 1, rightparacardial; 2, left paracardial; 3, lesser curve; 7, left gastric; 8,common hepatic; 9, coeliac axis; 11, splenic artery

plexus The para-oesophageal nodes lie

along the oesophageal wall draining to

peri-oesophageal nodes and more distant lateral

oesophageal nodes Ultimately these empty into

the thoracic duct although direct connections

between the oesophageal plexus and the duct

may also be present This arrangement allows

for early and widespread lymphatic

dissemina-tion of oesophageal carcinoma once the

base-ment membrane has been breached

Lymph node status is a profound prognostic

factor for oesophageal carcinoma and the

pattern of dissemination derived from resected

specimens suggests that the lymphatic drainage

broadly mirrors the arterial blood supply The

upper oesophagus drains in a mainly cephalic

direction to the cervical nodes; the middle

oesophagus to the oesophageal,

para-aortic and tracheo-bronchial stations; the lower

oesophagus to both these mediastinal stations

and upper abdominal stations, particularly the

paracardial nodes and those along the left

gastric artery (Figure 1.5) This direction of

lym-phatic flow has been confirmed by radionuclide

studies following endoscopic injection of a

radioactive tracer at different levels of the

oesophagus According to the TNM (tumour,

node, metastasis) classification the regional

lymph nodes are, for the cervical oesophagus,

the cervical nodes including the supraclavicular

nodes, and, for the intrathoracic oesophagus,

the mediastinal and perigastric nodes,

exclud-ing the coeliac nodes (considered M1a nodes)

[3] The precise nomenclature differs slightly

from the description by the Japanese Society

[9] (Figure 1.5) although the two systems are

broadly similar

Nerve Supply of the Oesophagus

The innervation of the oesophagus comprises

an extrinsic parasympathetic and sympathetic

supply and the intrinsic intramural plexuses It

is controlled by a complex swallowing centre

located in the brainstem, which coordinates and

interprets signals from within the brainstem

and from peripheral receptors in the pharynx

and oesophagus

Parasympathetic Supply

This provides the predominant motor and

sensory innervation of the oesophagus The

fibres originate from the vagal motor nuclei andare distributed to the oesophagus via the vagusnerve to form the oesophageal plexus The glos-sopharyngeal nerve and the recurrent laryngealbranches of the vagus also carry some fibres tothe proximal oesophagus

Sympathetic Supply

This appears to play a more minor role inoesophageal function The preganglionic fibresoriginate from the fifth and sixth thoracic spinalcord segments and pass to the cervical, thoracicand coeliac ganglia The postganglionic fibresterminate in the myenteric plexus within theoesophageal wall

Intramural Plexuses

The myenteric (Auerbach’s) plexus lies betweenthe circular and longitudinal muscle layers andbecomes more prominent in the smooth muscleportion of the oesophagus Degeneration of themyenteric plexus in the region of the loweroesophageal sphincter results in achalasia of thecardia, a major motor disorder of the oesopha-gus, which is characterised by failure of thelower oesophageal sphincter to relax upon swal-lowing The submucosal (Meissner’s) plexus ismore sparse, containing nerve fibres but noganglia

The neural control of the oesophagus will becovered in greater detail when the physiologicalcontrol of oesophageal function is considered

Physiology of the Oesophagus

Fasting State

In the fasting state the oesophageal body isrelaxed and the upper and lower oesophagealsphincters are tonically contracted to preventgastro-oesophageal reflux and aspiration Theintraluminal pressure is atmospheric in the cer-vical oesophagus but more distally it becomesnegative and approximates with intrapleuralpressure, fluctuating with respiration (–5 to–10 mmHg on inspiration, 0 to +5 mmHg onexpiration) The short intra- abdominal portion

of the oesophagus lies in the slightly positive

1 · UPPER GASTROINTESTINAL SURGERY

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