Surgical Disease of the Oesophagus Flashcards
What feature of the oesophagus protects against damage by abrasion?
Tough lining of stratified squamous epithelium (mucosa)
What allows effective peristalsis to move food/liquids to the stomach and keep the oesophageal lumen empty?
two well developed coats of skeletal muscle (tunica muscularis) that spiral and cross each other in the oesophageal wall
What property of the oesophagus allows marked distension of the oesophagus when swallowing large food boluses?
longitudinal folds in the collapsed empty state
What feature of the oesophagus allows the entry and exit respectively of food and liquids and limit the presence of food/liquid within the oesophagus to a short duration of time after swallowing?
The upper and lower oesophageal sphincters
The structure of the oesophagus is different in the cat and dog.
Is this statement true or false?
True
The canine oesophagus has skeletal muscle throughout its length whilst the terminal few centimetres of the feline oesophagus has smooth muscle within the tunica muscularis.
What are the primary pathophysiological mechanisms of disease of the oesophagus? (4)
- Inflammation
- Dysmotility
- Obstruction - intraluminal, mural, extramural
- Traumatic injury
Name the pathophysiological mechanism for chronic regurgitation/ingestion of caustic or hot substance?
Inflammation
Name the pathophysiological mechanism for megaoesophagus.
Dysmotility
Name the pathophysiological mechanism for Oesophaeal FB?
Intraluminal obstruct
Name the pathophysiological mechanism for oesophgeal stricture?
Mural obstruct
Name the pathophysiological mechanism for vascular ring anomaly
Extramural obstruct
Name the pathophysiological mechanism for stick injury/cervical dog bite wound
Traumatic
Main 2 clinical signs of oesophageal disease?
Regurgitation
Dysphagia
Common but not main signs of oesophageal dx?
Cough
Dyspnea
Ptaylism
Fever
Lower appetite
Pathogenesis of nasal discharge with oesophageal dx?
Aspiration of food contents into the nasopharynx and/or trachea is common in patients with frequent regurgitation –> Inflammatory rhinitis
Pathogenesis of pneumonia with oesophageal dx?
Aspiration of food contents into the nasopharynx and/or trachea is common in patients with frequent regurgitation –> Aspiration pneumonitis
How to possible investigations into oesophageal disease? (8)
- History and CE
- Haematology + biochem
- Fluroscopy barium swallow
- Plain cervical xrays
- Thoracic xrays
- +ve contrast studies
- CT
- Oesophagoscopy
Which reflex will you assess to check if a patient is able to swallow?
Gag relfex
How to perform gag reflex?
Open patient’s mouth, touch patient’s larynx/tongue base.
Which cranial nerves does the gag reflex access?
Cranial nerves 9 and 10
Other than haem/biochem, what specific blood tests could be performed to investigate the oesophaus?
Ach antibodies - Myasthenia Gravis
What are the challenges of Fluroscopy? (3)
- Staff must be present within the room during radiation exposure to restrain the patient and to keep the fluoroscopy beam focussed on the patient, therefore there is a risk of radiation hazard to staff;
- The study is dependent on the patient eating and being co-operative;
- The patient is conscious, and the study is dependent on the patient remaining reasonably still.
Reasons the oesophagus has higher rates of complications historically. (4)
- does not have a serosa;
- has a segmental blood supply;
- has no omentum;
- is in constant motion due to swallowing and breathing.
Why may a serosal layer play a role in healing?
The serosa allows formation of an early fibrin seal by providing a source of pluripotent stem cells therefore may be important
Which area of the oesophagus has no layer equivalent to the serosa and therefore possibly effect healing?
Cervical
What overlays the thoracic oesophagus which is thought to act like the serosa?
Mesothelium
Experimentally, how necessary has the serosa been shown to be for visceral healing?
Unnecessary
What has latest data shown the blood supply of the oesophagus to be like?
It is now thought that disrupted oesophageal healing is more likely to arise if the intramural blood vessels are disrupted rather than the segmental blood supply.
How can we solve the lack of omentum in the oesophagus region?
The omentum can be lengthened, tunnelled through the diaphragm and used to support thoracic oesophageal surgical wounds.
Why is constant motion a poor reason for the low healing rate in the oesophagus?
stomach/intestines undergo peristalsis and heal
How many tension come about with an oesophageal wound?
Resect and anastomosis
How many Halstead principles are there?
7
What are Halstead’s surgical principles?
Strict aseptic technique
Gentle tissue handling
Meticulous haemostasis
Preservation of the blood supply
Closure with minimal tension on tissues
Anatomical closure with accurate tissue apposition
Obliteration of dead space
What should be done to the oesophagus before incision?
Suction the oesophageal lumen prior to incising the oesophagus, or immediately after incision to reduce local contamination of tissues with oesophageal contents;
Where should be incised on the oesophaus? (2)
- Incise through healthy oesophageal tissue;
- Choose the most advantageous approach to allow good exposure and access;
Which direction should an oesophageal surgical approach be?
Make a longitudinal oesophagotomy incision rather than a transverse incision because this is less likely to cause narrowing/stricture in healing;
What layer must be included when closing oeosphagus?
Submucosa
How many layer closure is recommended for oeosphagus?
1
Where should the knots be tied when closing oesophagus?
Extraluminal
What pattern to close oesophaus?
A simple interrupted appositional pattern is generally recommended; a simple continuous pattern is also suitable;
Suture material for oesophagus closure?
Use monofilament slowly absorbable suture material (such as polydioxanone or polyglyconate) to suture the oesophagus;
Where should sutures be placed compared to woud edge and also how far apart?
Sutures should be placed 3 mm from the cut edge of the oesophagus and 2-3 mm apart;
How can thoracic oesophagus be supported?
an omental flap tunnelled through the diaphragm;
Post op meds specifically for oesophaus? (3)
Assume postoperative oesophagitis will occur in most patients
- H2 receptor antagonists
- and/or proton pump inhibitors
- and/or gastric prokinetics;
What put be placed for nutrition after oesophgeal surgery? How long for? (2)
Place a gastrostomy or percutaneous endoscopic gastrostomy (PEG) tube to allow postoperative nutrition (for 5-10 days postoperatively) whilst resting the oesophagus and avoiding oesophageal distension by food boluses, etc;
How much of the oesophagus can be resected?
3-5cm
How to close oesophageal anastomosis?
Simple interrupted
Indication for oesophageal surgery? (Pathogenesis 3) (Examples 1 each)
- Relief of an oesophageal obstruction that cannot be removed by non-surgical means
= Intraluminal: endoscopically non-retrievable oesophageal foreign bodies;
= Intramural: resection of strictures that are refractory to balloon dilation;
= Extraluminal: transection of vascular ring anomalies; - Repair on an oesophageal tear or injury
= For example a bite wound, stick injury, following oesophageal foreign body retrieval; - Dysmotility
= Cricopharyngeal achalasia.
How to approach the oesophagus area:
- Cricopharyngeus muscle
(for treatment of cricopharyngeal achalasia)
Lateral cervical, incision centred over laryngeal region
How to approach the oesophagus area:
Most proximal oesophagus
(e.g. oesophageal stick injury)
Lateral cervical, incision centred over laryngeal region
How to approach the oesophagus area:
Cervical oesophagus
Ventral midline neck, separate the sternohyoid muscles and retract the trachea to the right
How to approach the oesophagus area:
Oesophagus at thoracic inlet/cranial thorax
Caudal ventral midline neck and cranial sternotomy
How to approach the oesophagus area:
Left cranial thoracic oesophagus
Left 3rd or 4th intercostal thoracotomy
How to approach the oesophagus area:
Right cranial thoracic oesophagus
Right 3rd, 4th or 5th intercostal thoracotomy
How to approach the oesophagus area:
Caudal oesophagus
Left 7th, 8th or 9th intercostal thoracotomy
How to approach the oesophagus area:
Caudal oesophagus and stomach
Combined ventral midline celiotomy and diaphragmatic incision or caudal sternotomy
What needs to be retracted to access oesophagus via aleft 3rd/4th intercostal thoracotomy? (2)
Retract the brachiocephalic trunk and subclavian vessels ventrally.
During a Left 7th, 8th or 9th intercostal thoracotomy to approach the caudal oesophagus. What anatomy must be aware of? (2)
- Dorsal branches of the left and right vagus nerve run along the side of the oesophagus and join to form the dorsal vagal trunk (which runs along the dorsal oesophagus).
- The ventral branches of the left and right vagus nerve run along the side of the oesophagus and join to form the ventral vagal trunk that runs along the ventral oesophagus.
How to position patient the best to access midline of oesophagus?
- Placing a sandbag under the neck in dorsal brings the vital anatomy nearer to the surface.
- Having the head as straight as possible, or even taping the head to the table, helps maintain the procedure at midline.
Which suture material for the oesophagus? (2)
Polyglyconate
Polydioxanone
(polyglecarprone looses tensile strength too quickly)
The commonest locations for foreign bodies to become lodged are? (3)
- Thoracic inlet
- Heart base
- Caudal oesophagus near diaphragm
What makes specific areas of the oesophagus more likely to have a FB?
Extraoesophageal structures limit oesophageal dilation at these locations making foreign body entrapment more likely.
Most common dog breed for oesophageal FB?
Small breed esp terriers
Which bone is most likely to get stuck?
Vertebra. The transverse processes on these bones can “dig” into the oesophagus which can make retrieval more difficult.
Clinical signs of an oesophageal FB? (6)
Retching, gagging, salivation, vocalisation, restlessness. Water and liquids can usually be swallowed and will pass the obstruction but solid food, if eaten, will be regurgitated immediately.
Cats with oesophageal foreign bodies present quite differently to dogs. Is this statement true or false?
True
Which of the following radiographic findings would suggest that there could be an oesophageal perforation or tear? (4)
Pneumomediastinum
Pleural effusion
Mediastinitis
Pneumothorax
After oesophageal FB removal, what should be performed?
Oesophagus should be re-examined endoscopically to assess the severity of damage and a lateral thoracic radiograph should be taken to assess for pneumomediastinum and/or pneumothorax that would indicate oesophageal perforation or tearing
How can you manage Perforations identified by a pneumomediastinum seen on post-retrieval radiographs?
Conservatively:
nil per os for 2-5 days. Consider placement of a gastrostomy or PEG tube, antibiotics, treatment of oesophagitis and analgesia.
When is surgery required for the oesophagus following FB? (4)
- There are radiographic signs of oesophageal perforation at the time of diagnosis
- Endoscopic retrieval of the foreign body has failed
- An oesophageal tear is seen on oesophagoscopy following foreign body retrieval
- There are radiographic signs of oesophageal perforation following endoscopic foreign body retrieval.
If we exclude lacerations secondary to oesophageal foreign bodies which have voluntarily been swallowed most other oesophageal injuries involve the A) oesophagus (rather than the B) oesophagus) so the anaesthetic and surgical approach is easier.
A) Cervical
B) Thoracic
What is Cricopharyngeal achalasia?
upper oesophageal sphincter fails to relax during the cricopharyngeal phase of swallowing. This prevents boluses of food passing from the oropharynx into the oesophagus.
How common is Cricopharyngeal achalasia?
Rare
What age of dogs suffer Cricopharyngeal achalasia?
Young
Which breed of dog suffers Cricopharyngeal achalasia?
Spaniel
How do does with Cricopharyngeal achalasia present?
Dogs with this condition make repeated attempts to swallow when eating. This causes marked distress and discomfort and is often accompanied by gagging, coughing, dropping food from the mouth, salivation, and nasal reflux of food. Often affected dogs may be underweight but are really hungry.
How is cricopharyngeal achalasia diagnosed?
after ruling out other causes of dysphagia and identifying failure of the food bolus to pass into the oesophagus during the cricopharyngeal phase of swallowing on a fluoroscopic barium swallow study.
What must be assessed when diagnosing cricopharyngeal achalasia and why?
oesophageal motility is assessed in dogs with cricopharyngeal achalasia because any oesophageal motility will be unaffected by treatment of cricopharyngeal achalasia.
What must Cricopharyngeal achalasia be differentiated from?
pharyngeal dysphagia
What is pharyngeal dysphagia caused by?
weakness of the pharyngeal constrictor muscles
How is cricopharyngeal achalasia treated?
excision of one half of the cricopharyngeus muscle
How do you approach surgery of cricopharyngeal achalasia?
A lateral approach is made to the larynx and the cricopharyngeus muscle is identified overlying the cricoid cartilage.
How is the surgery for cricopharyngeal achalasia performed?
The cricopharyngeus muscle is transected ventrally and then it is carefully dissected free from the oesophagus towards the dorsal midline where it is cut to remove approximately half of the muscle (i.e. the lateral portion of muscle). The wound is closed routinely.
How soon are results seen after surgery for cricopharyngeal achalasia?
Immediately
What is a vascular ring anomaly?
congenital malformation of the great vessels and their branches causes a constriction around the oesophagus. This acts as an extraluminal oesophageal obstruction and limits oesophageal dilation at the level of the vascular ring
Following surgery for cricopharyngeal achalasia; What can develop after surgery because of perioperative inflammation and occasionally dogs will have recurrence of clinical signs due to fibrosis;
pharyngeal dysfunction
What vascular ring anomaly makes up for 95% of cases?
4th aortic arch
What does the ductus arteriosus become at birth?
ligamentum arteriosus
Which side of the heart does the aorta, ductus arteriosus and pulmonary artery develop on?
LHS
How does persistent aortic arch present?
Onset of regurgitation when the animal is weaned onto semi-solid or solid food.
What do plain radiographs show with persistent aortic arch?
dilation of the oesophagus cranial to the heart base. Changes consistent with aspiration pneumonia are often present
What will a fluoroscopic barium swallow study demonstrate with Vasc ring anomaly?
Abrupt and extreme narrowing of the oesophagus at the heart base with passage of only small amount of liquid barium into a normal caudal oesophagus.
What does oesophagoscopy show with vascular ring anomaly?
acute oesophageal narrowing, through which the endoscope is unlikely to pass, at the heart base.
Prior to surgical correction of a vascular ring anomaly, what needs to be corrected? (2)
managed medically initially to improve their nutritional status and reduce oesophagitis secondary to regurgitation.
What are the feeding requirements for patients with a vascular ring anomaly prior to surgery? (3)
Feed small frequent meals of soft/liquid food.
The food bowl should be elevated such that the dog is standing up their back legs and the thoracic oesophagus is approximately vertical so that gravity can assist liquid passage through the construction.
For extremely debilitated patients a gastrostomy tube can be surgically placed, and the patient be fed exclusively by this route to improve their body condition prior to surgery.
What is oesophagititis due to with a vascular ring anomaly?
Oesophagitis in these cases is due to retention of food cranial to the heart base.
Why is referral recommended for vascular ring anomaly? (4)
The vascular ring is accessed via thoracotomy which provides challenges for anaesthesia and postoperative recovery;
Most surgeons will have limited experience of thoracic surgery and no experience of surgical treatment of a vascular ring anomaly;
The surgeon should be able to recognise and manage a range of vascular anomalies that might not have been clearly determined on preoperative investigations;
Failure to address all vascular anomalies or to dissect any fibrous bands that have developed around the oesophagus at the site of the vascular ring due to scarring will result in continued oesophageal constriction and persistent clinical signs with progression of oesophageal distension and dysmotility.
Why may oesophageal resection be needed?
- Neoplasia
- Severe circumferential damage
How much of the oesophagus can be resected?
3-5cm
What can be performed during oesophagus resection to reduce tension?
partial myotomy
How is a parital myotomy of the oesophagus performed?
The outer layer of oesophageal muscle is incised 2-3 cm proximal or distal (or both) to the anastomosis leaving the inner muscle later intact. The myotomy can heal by second intention.
