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Principles of gastrointestinalendoscopy Tatiana Martin

Kat Schwab

Sukhpal Singh

Abstract Endoscopes, both rigid and flexible, are used in many surgical specialties.

They allow for minimally invasive investigations of symptoms, diagnosis

of pathology and application of directed therapies. Although the ability to

see inside the human body has challenged pioneers of medical science for

centuries, it is only in the last 100 years that technology has evolved to

produce the advances in computers, fibreoptics and mechanics required

for endoscopy.

This article provides an overview of rigid and flexible endoluminal

endoscopy, focussing on the common examinations of the GI tract,

namely oesophagogastroduodenoscopy (OGD), sigmoidoscopy and colo-

noscopy. Laparoscopy, the most common form of rigid endoscopy, is dis-

cussed elsewhere in this series.

Keywords Colonoscopy; complications; endoscopy; flexible endoscopy;

history of endoscopy; oesophagogastroduodenoscopy; procedure; proc-

toscopy; rigid endoscopy; sigmoidoscopy

What is endoscopy?

The word ‘endoscopy’ comes from the Greek Endon ¼ inside and

Skopeo ¼ to look at, therefore an endoscope is defined as an

instrument that can be introduced into the body to view its in-

ternal parts. Endoscopy can be subdivided into rigid and flexible.This article discusses the basics of gastrointestinal (GI) flexible

and rigid endoscopy.

A brief history of endoscopy

The first endoscope came from Bozzini, a German urologist in

1806. He used concave mirrors and candlelight to allow exami-

nation of the bladder through a hollow tube, called the ‘Licht-

leiter’ (light conductor). Nitze later improved on Bozzini’s work

with the addition of an electric light. The first laparoscopy was

performed in 1901 on a dog, by George Kelling who realized the

importance of insufflating air into the abdomen and coined the

term ‘coelioscopy’. Human laparoscopy was first performed in

1910 by a Swedish surgeon called Jacobaeus. Technological ad-

vances in the post-war period of the 1950s saw the birth of

fibreoptics and Hopkin’s fibreoptic endoscope allowing flexible

scopes suitable for use in the GI tract. Endoscopy was trans-

formed in the 1980s by the invention of the video computer chip

that enabled the image from the endoscope to be magnified and

then displayed on a television screen. The advent of wireless

technology revolutionized our ability to visualize the smallbowel by way of capsule endoscopy, which allows 360-degree

views as well as measurement of pH, temperature and pres-

sure. Further innovations in instrumentation and technology are

already being made, from high-definition and three-dimensional

images, to single port access surgery and the use of robotics.

Current types of endoscopy are listed in Table 1.

The flexible endoscope

Although there are many different applications for the flexible

endoscope, the basic equipment is similar between all types of

scopes. The main equipment includes the endoscope, stack and

instrumental tools.

Endoscope:

fibreoptic system to conduct light from a source through

the scope to its tip

chip camera positioned at tip and connector system to

relay image back to screen

plumbing systems with independent channels to allow

irrigation of tip, suction and insufflation

working channel for passage of instruments

control body (Figure 1) that houses the outlets for the

plumbing systems, ports for access to the working chan-

nel(s) and the control knobs which allow rotation of the

distal tip in two planes.

Stack ( Figure 2 ):

light source

insufflator system

suction unit and water reservoir

electrosurgical unit, including argon plasma system

image recorder (video/digital recorder; photo-capture and

printer).

Instruments/extras:

biopsy forceps

snares

injecting needles

electrosurgical probes

dilating and stenting kits

banding devices for variceal treatment & EMR (endoscopic

mucosal resection).

Gastrointestinal flexible endoscopy

Joint Advisory Group on GI endoscopy (JAG)

“JAG” ensures the quality and safety of patient care by defining

and maintaining the standards by which endoscopy is practised

in the UK www.thejag.org.uk. JAG provides nationwide training

for doctors and nurses through regional training and mentored

assessment programmes, as well as running centralized basic

and advanced skills courses. To practise independently as an

endoscopist, JAG certification is needed and course attendance

compulsory, although for surgical trainees this is not expected

Tatiana Martin MBBS BSc MRCS is an ST3 in General Surgery at The Royal

London Hospital, London, UK. Conflicts of interest: none declared.

Kat Schwab MBBS(Hons) BSc(Hons) MRCS is a Surgical Specialist Registrar

and MATTU Research Fellow at Royal Surrey County Hospital, Surrey,

UK. Conflicts of interest: none declared.

Sukhpal Singh FRCS is a Consultant Upper Gastrointestinal and General

Surgeon at Frimley Park Hospital, Surrey, UK. Conflicts of interest: none

declared.

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SURGERY 32:3 139 2013 Elsevier Ltd. All rights reserved.

http://www.thejag.org.uk/

http://dx.doi.org/10.1016/j.mpsur.2013.12.010


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Types of endoscopy Flexible endoscopy

Body system Name of endoscopy What is visualized/accessed

Gastrointestinal (GI) tract Oesophagogastroduodenoscopy (OGD) Oesophagus, stomach and duodenum

Enteroscopy Small intestineColonoscopy Large intestine (and terminal ileum)

Sigmoidoscopy Sigmoid colon, rectum

Endoscopic ultrasound (EUS) Upper GI tract and biliary tree

Biliary tree, hepatic ducts Endoscopic retrograde

cholangiopancreatography (ERCP)

Pancreas, common bile duct, hepatic ducts,

gallbladder

Choledocoscopy e intraoperative or peroral

(Spyglass for example)

Access to bile ducts for biopsy and lithotripsy

Respiratory tract Bronchoscopy/endobronchial ultrasound Trachea, large and small bronchi

Ear, nose and throat Rhinoscopy Nose

Laryngoscopy Throat

Urological Cystoscopy Bladder, urethra

Ureteroscopy Ureters

Gynaecological Hysteroscopy UterusFalloscopy Fallopian tubes

Rigid endoscopy

Type of procedure Speciality Example of use

Laparoscopy All subspecialities Diagnostic

Upper gastrointestinal surgery Bariatric procedures

Nissen fundoplication

Cholecystectomy

Splenectomy

Lower gastrointestinal surgery Appendicectomy

Colectomy

Gynaecology Hysterectomy

Salpingo-oophorectomy

Bladder neck repair (incontinence)

Thoracoscopy Vascular surgery Cervical sympathectomy

Thoracic surgery Video-assisted thoracoscopic surgery (VATS)

Extraperitoneal

laparoscopy

General surgery Hernia repair (inguinal, femoral, obturator)

Endocrine surgery Thyroidectomy/parathyroidectomy

Vascular surgery Subfascial endoscopic perforator surgery

(SEPS)

Urology Adrenalectomy

Nephrectomy

Prostatectomy

Endoluminal Lower gastrointestinal surgery Rigid sigmoidoscopy/proctoscopy

Head and neck surgery Rigid nasendoscopy/laryngoscopy/

oesophagoscopy

Urology Cystoscopy/ureteroscopy

Trans-urethral resection of the prostate

(TURP)

Gynaecology Hysteroscopy

Arthroscopy Orthopaedic surgery Diagnostic

Removal of intra-articular loose bodies

Trimming cartilage

Anterior cruciate ligament reconstruction

Table 1

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until after the fifth year of registrar training. JAG also provides

guidance on the set up and running of endoscopy units, to ensure

universal standards are met.

Endoscopy units

Gastrointestinal flexible endoscopies are usually performed in dedi-

cated endoscopy day units with specially trained staff. The units

consist of a reception and waiting area for patients, with easily

accessible toilet facilities, individual private treatment rooms for the

provisionof theendoscopy, a step-down/recovery area,cleaningand

sterilizing facilities for the turnaround of the scopes and adminis-

tration offices. The most commonly performed gastrointestinal en-

doscopies are oesophagogastroduodenoscopy and colonoscopy.

Sedation and monitoring Patient tolerance of endoscopic procedures may be improved

with sedation and locally administered analgesic agents. National

guidelines exist with evidence-based recommendations, sum-

marized as follows:

safe secure intravenous (IV) access (non-butterfly) to be

used and remain until post-recovery

continuous non-invasive blood pressure and pulse oxim-

etry monitoring

continuous peri-procedural oxygenation of patient

benzodiazepine and opioid IV to be used as sedative and

analgesic

appropriate dose for age and physiological condition of

patient, given as small aliquots and titrated good communication with nursing staff regarding dosage

and vital signs

awareness of cardiopulmonary complications of drugs and

their management (head down and IV fluids for low blood

pressure, over-sedation and respiratory depression

requiring reversal agents and appropriate resuscitation)

clear thorough documentation of entire procedure not just

endoscopic findings.

Consent

Before undergoing an endoscopy, patients should have under-

gone the process of giving informed consent e adequate

procedural information given, risks and complications explained,

co-morbidities and possible use of sedation addressed with

ample opportunity for questions to be answered. Consent is

usually supported with information leaflets.

Upper gastrointestinal tract endoscopy

Indications

Diagnostic to investigate causes of anaemia, upper GI haemorrhage,

persistent vomiting

to investigate upper GI symptoms including dyspepsia,

reflux, dysphagia (difficulty in swallowing) and odyno-

phagia (pain on swallowing)

Surveillance

review of peptic ulcer healing

Barrett’s Oesophagus

post-surgery

Biopsying

CLO test for Helicobacter pylori

duodenal biopsy for coeliac disease

mucosal biopsy for pathology Therapeutic

intervention of upper GI bleeding e including adrenaline

injection, clips, gold probe

variceal treatment e including injecting, banding and glue

polyp snaring

removal of foreign bodies

dilatation of strictures or achalasia

stenting

Specialist endoscopic procedures

EUS (endoscopic ultrasound assessment of organs), EUS

guided FNA (fine needle aspiration), EUS guided coeliac

axis block

endoscopic retrograde cholangiopancreatography

(ERCP) e utilizing a side-viewing scope and fluoroscopy

to access the bile and pancreatic ducts

percutaneous endoscopic gastrostomy (PEG) insertion,

guidance of enteral feeding tubes under direct vision

endoscopic or EUS-guided drainage (e.g. pancreatic

pseudocysts)

radiofrequency ablation of dysplastic Barrett’s

Oesophagus

EMR, submucosal dissection and PerOral Endoscopic

Myotomy (POEM).

The procedure

Patients are kept nil by mouth for 4e6 hours before the proce-

dure. Local anaesthetic spray is administered to the oropharynx

to reduce the gag reflex and intravenous sedation may be

administered. The patient lies on their left side with monitoring

attached and a mouth guard is placed between their teeth to

prevent scope damage. The endoscopist, after checking that the

scope has been connected to the stack correctly (light, suction,

insufflation and irrigation), gently passes the scope over the

tongue and manoeuvres through the pharynx to intubate the

oesophagus. The scope is passed through the oesophagus and

stomach through to duodenum under direct vision, noting pa-

thology as seen. Retroflexion or J-manoeuvre allows for full

Rigid sigmoidoscopeProctoscope

Light source

and eyepiece

Proctoscope light

connector

Manual insufflator

Figure 1

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vision of the fundus of the stomach and the gastro-oesophageal

junction (GOJ). Any extra instrumentation such as biopsy can

be performed and photographs may be taken as evidence of

findings. Any insufflated gas can be removed by suctioning onwithdrawal of the scope.

Risks/complications of oesophagogastroduodenoscopy (OGD)

The risk of complications is quoted as approximately 1 in 1000,

increased in therapeutic procedures.

The main risks in order of most common are:

cardiopulmonary problems (aspiration, respiratory

depression, hypotension, arrhythmias)

perforation

bleeding

injury to teeth.

Lower gastrointestinal flexible endoscopy

Indications

Diagnostic

investigation of change of bowel habit, especially diar-rhoea and increased frequency of stool

investigate anaemia (usually in conjunction with OGD)

investigate symptoms including abdominal pain, bloat-

ing, weight loss and unexplained rectal bleeding

Surveillance

inflammatory bowel disease

polyposis

post-cancer surgery

Biopsying

terminal ileum biopsies for Crohn’s disease

biopsying pathology visualized on radiological imaging

Light source and

insufflation system

Electrosurgical unit

Monitor

Image recording systems,

photo-capture and printer

Suction unit and

water reservoir

Stack systems and extras for flexible endoscopy

Figure 2

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tattooing lesions for laparoscopic resection

Therapeutic

snaring polyps

APC or laser therapy to vascular anomalies

haemorrhage control

stenting

Screening for cancer

positive faecal occult blood results (FOBs) in the na-tional screening programme

strong family history

familial polyposis syndrome.

The procedure

Bowel preparation is required before lower GI endoscopy to

ensure clear vision of all colonic mucosa. This consists of 2e3

days of a low-fibre diet prior to colonoscopy and prescribed oral

laxatives to clear the colon the day before (for colonoscopy) or

enemas on the day (for flexible sigmoidoscopy). Care needs to be

taken with preparation in patients with significant renal or car-

diovascular comorbidities due to the osmotic laxative effects. If

there are concerns, a patient can be admitted for administrationof the preparation and supplemental intravenous fluid. Intrave-

nous analgesia and sedation are given before the procedure to

help the patient tolerate the colonoscopy. This is not usually

required for flexible sigmoidoscopy.

A digital rectal examination is performed first to check sphincter

tone, assess bowel preparation, lubricate the anus and ensure no

anal lesions have been missed. The colonoscope is then inserted

into the anus and guided through the rectum and colon (sigmoid,

descending, transverse and ascending) to the caecum and possibly

terminal ileum. Sigmoidoscopy will visualize the left colon. Insuf-

flation is required to visualize the lumen. ‘Looping’ of the colono-

scope in the non-fixed colon may result in discomfort for the patient

and lack of forward progress. Methods to resolve formation of theloop and prevent recurrence can include torque application to the

scope, fixation of scope tip and withdrawal to straighten the scope,

stiffening of the scope, repositioning of the patient and pressure

applied by an assistant to the patients abdomen. To try to ensure

that no pathology is missed, slow withdrawal of the scope is

advised. Polyps can be snared, biopsies and photographs taken and

interventions performed throughout the procedure.

Risks/complications of lower GI endoscopy

Cardiopulmonary problems (as listed for OGD).

Dehydration from bowel preparation.

Perforation (risk increases with biopsy and polypectomy)

0.2%.

Bleeding 1.5%.

Rigid endoscopy

Rigid endoscopes allow access to shallow and easily accessible

cavities,suchas in thehead andpelvis fordiagnostic andtherapeutic

purposes, or with surgical incisions for minimally invasive cavity

work, such as the chest, abdomen or joints. Surgical applications of

rigid endoscopy are discussed further in a chapter on laparoscopy.

We will look briefly here on GI rigid endoscopies as an example.

Rigid sigmoidoscopy and proctoscopy are routinely performed

in OPD clinics and can be easily utilized in inpatient settings and

intra-operatively. They both require a simple light source and

sigmoidoscopy also uses gentle manual insufflation to aid visu-

alization of the rectum and distal sigmoid up to 25 cm. The

advantage of these procedures is that they can provide rapid

diagnosis, and in some cases treatment, without the need for

bowel preparation or sedation.

Proctoscopy Used for:

Diagnosis

benign anorectal disorders, such as haemorrhoids, fis-

sures, fistulae

carcinoma of anal canal or rectum

rectal polyps

other anorectal problems

Treatment

banding or injection of sclerosing agent to haemorrhoids

rectal washout intra-operatively on anterior resection or

faecal impaction relief.

Rigid sigmoidoscopy

Used for:

Diagnosis

mass lesions and mucosal abnormalities

bleeding from lower GI source

inflammatory rectal disease

biopsy

Treatment

conservative treatment of sigmoid volvulus

Intra-operatively

assess the ‘true’ height of a rectal cancer

inspect anastomosis.

The procedure

In theclinic setting, theexaminationis explainedto thepatient and

any questions are answered appropriately. It is essential to clarify

understanding and ensure that verbal consent is obtained. The

patient is placedon theexamining couch,in theleft lateral position

with buttocks exposed. Digital rectal exam (DRE) is then per-

formed, which allows lubrication of the anus, assessment of anal

tone andquality,improved comfort forthe patient andpalpation of

any lesions or abnormalities in anal canal or distal rectum. Most

scopes are disposable and familiarity with them is necessary to aid

positioning of the obturator,reusablelight sources and insufflation

connectors. The scope is lubricated and then gently inserted

through the anal canal before being rotated back 60

into therectum. It is not inserted any further without direct visualization so

as to avoid inadvertent injury or bleeding. The obturator is then

removed and disposed of, the light source attached and the

eyepiece closed. Gentle insufflation while looking through the

eyepiece allows visualization of the rectum as the scope is guided

forward through the valves of Houston (transverse folds of the

rectum). There is a distance gauge on the outside of the scope for

documentation of depth visualized or recording of where in the

rectum an abnormality has been observed. Biopsy forceps and

other instruments can be passed down the lumen as required.

Proctoscopy is approached in a similar manner and may be

performed after rigid sigmoidoscopy or alone after DRE for

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inspection of the anal canal and distal rectum. Be aware that the

connectors on your light source may need to be changed. The

obturator is easily reinserted for re-entry into the anal canal,

which is useful for detailed assessment of haemorrhoidal disease

and its descent. Therapeutic instruments such as Gabriel syringes

or banding devices can easily be passed through the lumen for

haemorrhoidal treatment.

Future developments in endoscopy

Imaging

High definition (HD) endoscopes e standard endoscopes

use less than 200,000 pixels to construct an image which

can limit detailed inspection of mucosa, however high-

resolution endoscopes (>850,000 pixels) are now

commercially available, which improves assessment of

structures and pathology, allowing endoscopists to make

more accurate “in vivo” diagnoses.

Narrow band imaging-filter enhances the quality of fine

structures and capillary network of the mucosal surfaces.

Light-induced fluorescence endoscopy (LIFE) e involves

passing of small probes through the endoscope to emit lightand stimulate certain moleculesdfluorophores, the re-

flected lightis detectedby miniature charge-coupled devices

(CCDs). Normal mucosa appears as a bright green back-

ground, however regions of increased haemoglobin (e.g.

ulcerated or thickened mucosa in flat/depressed tumours)

appear dark green while elevated tumours appear magenta.

Thistechnique aimsfor earlyidentification of pre-malignant

and malignant lesions that have minimal morphological

features on regular endoscopy

Photon endomicroscopy e utilizes fluorescence generated

by photons to construct an optical sectional image of tissue

endoscopically which is comparable to a traditional H&E-

stained biopsy. The limitation of this, however, is the

requirement of a trained specialist or histopathologist to

interpret the images

Endoscopes/endoscopic assistance

Endoscopes with full angulation ability up to 360.

Self-propelling endoscopes e scopes with gas propulsion

systems to ‘pull’ themselves around the colon.

Guiding systems e providing computer-generated scope

positioning to allow endoscopists improved awareness of

anatomical position of scope and information of direction

of loop formation.

Contrast EUS and EUS elastography may be able todistinguish between benign conditions such as chronic

pancreatitis and malignancy. If developed further, the

quantification of contrast to assess tumour characteristics

may even predict response to chemotherapy.

Development of smaller and smaller endoscopes (e.g.

scanning fibre endoscope [SFE]) that incorporate an optical

design to allow a large field of view despite their narrow

calibre as well as great flexibility. This is of particular use in

the visualization of biliary and pancreatic ducts.

Three-dimensional high-definition laparoscopes are

already on the market, with particular utilization in robotic

surgery, and further potential for application to flexible

endoscopic procedures.

Therapeutic tools

Advances in stents e shapes, materials including biode-

gradable, deployment systems, possible drug impregnation

for targeted delivery.

Dyes may be used to enhance contrast

Future techniques not yet fully in practice

Full-thickness mucosal resection of tumours.

NOTES e natural orifice transluminal endoscopic surgery

e the ability to reach intra-abdominal organs endoscopi-

cally through the mucosal wall of the GI tract (such as

stomach) and vaginal vault, with operating tools manipu-

lated through the work channels of an endoscope. There

has been reported success with appendicectomy and cho-

lecystectomy. The aim is to improve patient recovery,

reduce anaesthesia requirements and possibly allow day

surgery with minimal perioperative requirements.

Further development of capsule endoscopy to incorporate

computer-assisted diagnosis that would improve the la-

bour intensity of reporting. Other advances currently being

explored include local delivery of drugs in the small bowel

and biopsy using capsule endoscopy.

Integration of biological markers such as antibodies or

peptides, as well as fluorescence, to target specific markers

on tumours (e.g. HER2 antibodies). A

FURTHER READING

ASGE. Complications of upper GI endoscopy. Gastrointest Endosc 2002;

55: 784e

93.Bergman J, Tytgat G. New developments in the endoscopic surveillance of

Barrett’s oesophagus. Gut 2005; 54: i38e42. http://dx.doi.org/10.

1136/gut.2004.041590.

Bozzini PH. Lichtleiter, eine Erfindung zur Anschauung innerer Teile und

Krankheiten. J Prak Heilk 1806; 24: 107.

Green J. Complications of gastrointestinal endoscopy. Available at: http://

www.bsg.org.uk/pdf_word_docs/complications.pdf .

Guelrud M, Herrera I, Essenfeld H, et al. Enhanced magnification endos-

copy: a new technique to identify specialized intestinal metaplasia in

Barrett’s esophagus. Gastrointest Endosc 2001; 53: 559e65.

Hart R, Classen M. Complications of diagnostic gastrointestinal endos-

copy. Endoscopy 1990 Sep; 22: 229e33.

Haycock A, Oppong KW. The future developments in endoscopy. FrontlineGastroenterol 2012; 3: i19e23. Also available at: http://fg.bmj.com/

content/3/Suppl_1/i19.full.html#ref-list-1 .

Majumdar SK. A short history of gastrointestinal endoscopy. Bull Indian

Inst Hist Med Hyderabad 1993; 23: 67e86.

Sivak MV. Gastrointestinal endoscopy: past and future. Gut 2006; 55:

1061e4.

Standards of Practice Committee of the American Society for Gastro-

intestinal, Lichtenstein DR, Jagannath S, Baron TH, et al. Sedation

and anesthesia in GI endoscopy. Gastrointest Endosc 2008 Nov; 68:

815e26.

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