Background
Surgical
anatomy
The oesophagus is a muscular tube
approximately 25 cm Ion occupying the posterior mediastinum and extending from
if cricopharyngeal sphincter to the cardia of the stomach; 2 cm of this tube
lies below the diaphragm. The musculature of if upper 5 per cent, including the upper oesophageal sphincter is striated;
the middle 40 per cent has mixed striated an smooth muscle with the proportion
of smooth muscle increasing distally; the distal 55 per cent is entirely smooth muscle It is lined by squamous
epithelium. The parasympathetic nerve supply is mediated by the vagus which has
synaptic connections to the myenteric (Auerbach’s) plexus. Meissner submucous
plexus is very sparse in the oesophagus.
There
is an upper and a lower oesophageal sphincter. The upper sphincter is powerful
striated muscle, while the lower sphincter is much more subtle, but the elegant
studies
Liebermann-Meffert have shown that there is an
anatomic sphincter at the gastro-oesophageal junction. The arch of the aorta makes a definite impression on the oesophagus that can be seen on
a radiograph (Fig. 50.1) or during endoscopy. It is helpful to remember the
distances 15, 25 and 40 for anatomical
location during endoscopy (Fig. 50.2).
Physiology
The main function of the oesophagus is to transfer food from the mouth
to the stomach in a co-ordinated fashion. The initial movement of food from the
mouth is voluntary. The
The
upper oesophageal sphincter is normally closed at rest and serves as a
protective mechanism against regurgitation of oesophageal contents into the
respiratory passages, but it also serves to stop air entering the oesophagus
other than the small amount that enters during swallowing. Failure to relax on
swallowing may predispose to the development of a pharyngeal pouch (pulsion
diverticulum).
The
lower oesophageal sphincter (LOS) prevents gastric and duodenal contents from
refluxing into the lower oesophagus (Fig. 50.4).
The tone of the sphincter is influenced by many things including food,
gastric distension, smoking and gastrointestinal hormones. The diaphragm also
contributes to the action of the LOS. The function of the physiological
sphincter was first demonstrated by Code by manometry using small balloons (Fig.
50.5).
Nowadays LOS pressure is
measured by perfused tubes or microtransducers. The normal LOS is 3—4 cm long
and has a pressure of 10—25 mmHg (or cmH2O).
Manometry
may also be used to assess peristalsis (Fig. 50.6). The LOS relaxes in advance
of the peristaltic wave. Primary peristalsis is induced by a swallow Secondary
peristalsis is the normal response to a stubborn food bolus or refluxed
material and also clears the oesophagus (Fig. 50.7). Clearance and
neutralisation of refluxed gastric acid is mainly achieved by primary
peristalsis which carries saliva with its
Symptoms
Dysphagia
Dysphagia is the term used to describe
difficulty, but not necessarily pain, on swallowing. The localisation of the
holdup may help to differentiate between an obstruction at the cnicopharyngeal
sphincter in the body of the oesophagus or at the lower end. The type of
dysphagia is important. It may be dysphagia for solids or fluids, intermittent
or progressive, precise or vague in its appreciation.
Odynophagia
Odynophagia refers to pain on swallowing.
Patients with reflux oesophagitis often feel burning retrosternal discomfort
within a few seconds of swallowing hot beverages, citrus drinks or alcohol.
Odynophagia may be particularly severe in chemical injury of the oesophagus.
Regurgitation and reflux
Regurgitation and reflux are terms that are
often used synonymously. It is helpful to differentiate between the two symptoms
although it is not always possible. Regurgitation should strictly refer to the
return of oesophageal contents from above an obstruction in the oesophagus
that may be functional or mechanical. Reflux is the passive return of
gastroduodenal contents to the mouth as part of the symptomatology of gastro-oesophageal
reflux disease. Loss of weight, anaemia, cachexia, change of voice due to
refluxed material irritating the vocal cords or recurrent laryngeal nerve palsy,
and cough or dyspnoea due to tracheal aspiration are all important symptoms of
oesophageal disorders.
Chest pain
Chest pain similar in character to angina
pectoris may arise from an oesophageal cause, especially gastro-oesophageal
reflux and motility disorders.
Investigations
Radiography
Contrast radiography has been somewhat
overshadowed by endoscopy, but remains a very useful investigation for
demonstrating narrowing, space-occupying lesions, anatomical distortion or
abnormal motility. An adequate barium swallow takes time to do and should be
tailored to the problem under investigation. It may be helpful to give a solid
bolus (bread or marshmallow) if a motility disorder is suspected. Video
recording is also useful to allow subsequent replay and detailed analysis.
However, it should be stressed that barium radiology is very inaccurate in the
diagnosis of gastro-oesophageal reflux, unless the reflux is gross, and should
not be used for this purpose. Plain radiographs will show opaque foreign bodies.
Endoscopy
Endoscopy is necessary for the investigation
of most oesophageal conditions. It is required to view the inside of
Rigid oesophagoscopy
Rigid oesophagoscopy is now virtually
obsolete, but some surgeons still cling to this traditional method. The most
commonly used instrument is the Negus oesophagoscope although there are newer
varieties with better quality distal lighting, such as the Earlam oesophagoscope
which is circular in cross section. Passage of a rigid oesophagoscope is a
skilful business and is relatively safe in the hands of an expert, but there is
still a significant risk of perforation. There may be something to be said for
the occasional use of a rigid instrument to examine the lower pharynx and the
cricopharyngeal area, since the view can be rather poor with a flexible endoscope,
in which case a shorter (and safer) laryngoscope is used. Most foreign bodies
may be removed with a flexible gastroscope and an overtube to protect the
oesophagus, but some may prefer to use the rigid instrument and large grasping
forceps especially for a large foreign body such as a set of dentures (Fig.
50.9). It should be noted that most modern dentures are not radio-opaque.
Dilatation of oesophageal
Fibre-optic endoscopy (see Chapter 51)
The flexible fibre-optic gastroduodenoscope
has virtually supplanted the rigid instrument for diagnostic and therapeutic
endoscopy of the oesophagus because it has many advantages. General
anaesthesia is not required, most examinations can be done on an out-patient
basis, the quality of the magnified image is superb, especially with modern
video-endoscopes, the instrument is much safer to pass and there is a greater
range of therapeutic devices. The technology of fibre-optic endoscopy continues
to improve at a steady pace.
As
a matter of routine the stomach and duodenum are examined as well as the
oesophagus. If a stricture is encountered if may be helpful to dilate it to
allow a complete inspection of the upper gastrointestinal (GI) tract, but this
advice should be tempered by clinical common sense. All endoscopic manipulations
involve a degree of risk and it is prudent to keep risks to a minimum.
Therapeutic
procedures
Dilatation of
strictures
The advent of guidewire directed dilatation of
the oesophagus in the 1970s has been a major advance. The Eder— Puestow
dilator (Fig. 50.11) was the first to be used. This had
Balloons
may also be used for dilatation of strictures. They come in many varieties. Some
are designed for passage down the biopsy channel, others for passage in the
X-ray department. In general balloons achieve rather less effective dilatation
than solid dilators, but they may be useful to begin dilatation of difficult
strictures.
Laser therapy
Lasers may be used to core a channel through a
cancer for palliation of dysphagia. Similar effects may be produced by bipolar
diathermy, injection of absolute alcohol or argon beam plasma coagulation.
Oesophageal manometry
Manometry is now widely used to diagnose
oesophageal motility disorders. Recordings are usually made by passing a
multilumen catheter with three to eight recording orifices at different levels
down the oesophagus and into the stomach. The catheter channels are perfused
with water by a low compliance pneumohydraulic pump for accurate measurement
of rapid pressure changes. The catheter is withdrawn progressively up the
oesophagus and recordings are taken at intervals of 0.5—1.0 cm to measure the
length and pressure of the LOS and to assess motility in the body of the
oesophagus during swallowing. Catheters with solid-state transducers are easier
to use and are becoming more popular, but are still rather expensive.
24-hour pH recording
Prolonged measurement of oesophageal pH is now
accepted as the most accurate method for the diagnosis of gastrooesophageal
reflux. A small pH probe is passed into the distal oesophagus and positioned 5
cm above the upper margin of the LOS as defined by manometry. The probe is
then connected to a miniature digital recorder which is worn on a belt