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 pharyngeal swallow response is triggered by stimulation of the pharynx and involves sequential contraction of the oropharyngeal musculature, together with simultaneous closure of the nasal and respiratory passages, and opening of the upper oesophageal sphincter. The body of the oesoph­agus then propels the food bolus by primary peristalsis, through a relaxed lower oesophageal sphincter, into the stomach, taking air with it (Fig. 50.3). Primary peristalsis is under vagal control.

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 high bicarbonate content down to the lower oesophagus. Tertiary contractions occur occasionally and are non­peristaltic waves (Fig. 50.8).

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 the oesophagus and the oesophagogastric junction, to obtain a biopsy or cytology specimen, for the removal of foreign bodies and to dilate strictures. Traditionally there are two types of instrument available — the rigid oesophagoscope and the flexible fibre-optic endoscope.

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   strictures has been done for many years with the rigid instru­ment and the classic Chevalier Jackson bougie (Fig. 50.10), but dilators that are passed over a guidewire are much safer and they are now in general use.

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 been produced by the Eder instrument company many years previously. The guidewire was intended to be passed blindly, but the method did not become popular until it was realised that the guidewire could be passed down the biopsy channel of an endoscope and through a stricture under vision. The endoscope is withdrawn leaving the guidewire in place and the dilators are passed over the guidewire. X-ray screening can be used to check that the wire is in satisfactory position and the dilators pass safely. With experience X-ray screening is rarely required, but may be reserved for difficult cases. To restore normal swallowing the stricture should be dilated to at least 16 mm diameter or 50 Fr. Charriêre, a French instrument maker, originally measured dilators in millimetres circumference, hence the use of French gauge. Guidewire directed dilatation of oesophageal strictures is now normal practice in most units and there are many different types of dilator. The Celestin stepped dilators (Fig. 50.12) are widely used in the UK and have the merit of being easy to pass since only two are required for complete dilatation.

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 and allows most normal activities. A 20—24-hour recording period is usual and the pH record is analysed by an auto­mated computer program using DeMeester’s criteria. In some cases with atypical symptoms it is useful to compare the relationship between symptoms and reflux episodes.