Anatomy and physiology refresher

Basic esophageal anatomy

  • Cervical, thoracic and abdominal portions.
  • Feline esophagus resembles the human one:
    • Proximal one-third: striated muscle.
    • Distal two-thirds: smooth muscle.
  • The dog, in comparison, has an esophagus which consists of two oblique layers of striated muscle.
  • Innervation: vagus nerve. Essential for normal peristalsis and esophageal function.

Basic esophageal physiology

  • Two functional sphincter areas:
    • Cranial (upper) esophageal sphincter: protects larynx during ingestion of food. Consists of the cricopharyngeal muscle.
    • Gastro-esophageal (lower) sphincter: a 'high pressure zone' which prevents gastric reflux between swallows and between meals.
  • Phases of swallowing:
    • Oropharyngeal: bolus negotiates relaxed cranial esophageal sphincter.
    • Esophageal: peristalsis through esophagus.
    • Gastro-esophageal: bolus passes through gastro-esophageal sphincter into stomach.
  • Normal function requires coordinated action of all sphincters and phases of swallowing.

Approach to the feline esophageal case

  • Signalment: young age   →   congenital disorders; old age   →   degenerative/neoplastic disease.
  • Detailed clinical history is a prerequisite.
  • Examination for concomitant or complicating problems: chest auscultation; temperature monitoring, etc.
  • Hospitalization: observe ingestion of food, any regurgitation, noting timing and patterns and whether the consistency of the food affects the patient's responses.
  • Baseline hematological, biochemical and serological parameters.

Common clinical signs of esophageal disease

  • Regurgitation: differentiate from vomiting.
  • Cough: may indicate aspiration pneumonia.
  • Dysphagia: may indicate disturbance of cranial esophageal sphincter.
  • Dyspnea: caused by aspiration pneumonia, pain, esophageal perforation, mediastinitis, pleuritis etc.
  • Ptyalism: blood-tinged with foreign bodies or esophageal ulceration/necrosis.
  • Pyrexia: in secondary pneumonias.
  • Weight loss: common in chronic disorders of the esophagus.
  • Non-specific signs: pain and depression associated with esophagitis, mediastinitis and pleuritis.

Regurgitation

  • Passive, no abdominal effort, undigested food, tubular-shaped regurgitated material.

Vomiting

  • Active retching, abdominal contractions, partly digested food with bile present.

Diagnostic modalities in esophageal disease

  • Radiography: plain, contrast (barium, aqueous iodine) and fluoroscopic studies all helpful.Be careful of barium if suspicion of esphogeal perforation.
  • Endoscopy: rigid and flexible.
  • Ultrasonography.
  • Exploratory surgery.

Basic surgical principles

General

  • No serosal layer in esophagus therefore careful suturing required to produce water-tight closure.
  • It is commonly thought that the mucosal layer holds most strength. However, studies have questioned this concept. Dallman (1988) showed that in dogs the submucosa alone had the same holding strength as the submucosa and mucosa together.
  • Suture line reinforcement can be achieved:
    • Sternohyoideus muscle.
    • Omental pedicles.
    • Diaphragm pedicles.
    • Intercostal muscle pedicles.
  • Avoid suture line tension, which can produce dehiscence.
  • Debride to healthy edges before suturing (severely traumatized cervical esophagus and surrounding tissue can be managed as an open wound prior to delayed closure but gastrostomy tube feeding Gastrostomy: percutaneous tube (endoscopic) would be required).
  • In thorax, do not compromise the broncho-esophageal artery, the main blood supply to the thoracic esophagus.

Suture patterns

  • Simple appositional sutures used in a two-layered closure of esophagus.
  • Layer 1: mucosa/submucosa is the most important, and strongest layer. Place knots in esophageal lumen. Use interrupted sutures.
  • Layer 2: muscle/adventitia. Place knots outwith the adventitial layer.

Suture materials

  • Use synthetic absorbable swaged-on sutures in mucosa/submucosa and the same or monofilament non-absorbable material in the muscle/adventitia.
  • Size 3/0 or 4/0 should be suitable for most feline patients.

To form an esophageal end-to-end anastomosis

  • Occlude the lumen cranial and caudal to the resection with atraumatic clamps.
  • Start by reapposing the two cut edges of the esophagus by the use of stay sutures dorsally and ventrally in each portion.
  • Commence sutures on the outer aspect of the far wall of esophagus: close the muscle/adventitia here.
  • Next close the mucosa/submucosa on the far wall.
  • Move to near wall. Close the mucosa/submucosa.
  • Finally, close the muscle/adventitia on the near wall.
  • Reinforce the suture line if necessary (see above).

Approach to the esophagus

  • Cranial thoracic area: right lateral thoracotomy.
  • Caudal thoracic area: left lateral thoracotomy.
  • Median sternotomy gives large exposure, however, the esophagus will be in a deep location and careful mediastinal dissections will be required.

Summary of surgical conditions of the feline esophagus

Foreign body

  • See esophageal foreign body Esophagus: foreign body for further detail.
  • Treatment: fluid and electrolyte support, then:
    • Endoscopic retrieval (flexible/rigid).
    • Propulsion into stomach followed by gastrotomy (but bony material will dissolve).
    • Esophagotomy if other methods fail.
  • Post-operative: fluid support, antibiotics, nil by mouth 24-48 hours, gastrostomy tube nutrition for severely damaged esophagus (for 5-7 days).Always check the base of a cat's tongue for thread or wool entrapment.

Perforation

  • See esophageal perforation Esophagus: perforation for further detail.
  • Treatment: very small defects - conservative treatment: fluid support, antibiotics, gastrostomy tube feeding if required, close observation; larger defects - surgical repair/reconstructive procedures, aggressive treatment for sepsis, thoracic drainage.
  • Complications: mediastinitis, pleuritis - rapidly fatal conditions.

Stricture

  • See esophageal stricture Esophagus: stricture for further detail.
  • Treatment: bougienage, balloon dilatation repeated weekly combined with prednisolone Prednisolone to limit fibroplasia.
  • Surgical intervention may be required: esophagoplasty to increase lumen or resection and anastomosis to resect the stricture completely.
  • Complications: minor hemorrhage after dilatation/bougienage; occasionally perforation.

Hiatal hernia

  • Protrusion of distal esophagus/cardia through the esophageal hiatus of diaphragm.
  • Congenital and traumatic causes of enlarged diaphragmatic hiatus.
  • Signs: intermittent vomiting/regurgitation, gagging, dysphagia, weight loss, reflux esophagitis, dyspnea, obstruction in severe cases.
  • Diagnosis: radiography, fluoroscopy for intermittent 'sliding' hernias, endoscopy to diagnose secondary esophagitis. Application of broad abdominal pressure during fluoroscopy/radiography may help to diagnose sliding hernias.
  • Treatment: antacids, metoclopramide. If unresponsive, surgical objectives:
    • Increase resistance of lower esophageal sphincter.
    • Reduce (plicate) the esophageal hiatus.
    • Pexy fundus of stomach to left abdominal wall.
  • Nissen fundoplication shows promise (seek referral advice).

Gastro-esophageal intussusception

  • Similar condition to hiatus hernia.
  • The stomach and perhaps other abdominal organs prolapse into the distal esopahgus.

Vascular ring anomalies

  • See vascular ring anomalies Vascular ring anomaly for further details.
  • Diagnosis: history highly suspicious, confirmed by radiography, fluoroscopy, endoscopy. On dorsoventral view of heart, the aortic bulge will be absent.
  • Treatment: ligation and transection of ligamentum arteriosum via a left-sided 4th intercostal thoracotomy. Bougienage then applied across constriction.
  • Some dysfunction may persist after surgery due to scarring, hypomotility or extra-luminal fibrosis. Further surgery may help. Elevated feeding position may help.

Neoplasia

  • Primary neoplasia: squamous cell carcinoma in old cats. Secondary malignancies are possible in the esophagus.
  • Signs: non-specific, regurgitation, weight loss, anorexia, hematemesis, pain.
  • Diagnosis: radiography, endoscopy and endoscopic biopsy.
  • Treatment: palliative in many cases. Resection and reconstructive procedures possible and may necessitate gastric mobilization.

Peri-esophageal masses

  • Compression of esophagus is caused.
  • Cause: mediastinal lymphoma Lymphoma in young cats; thymoma in old cats.
  • Signs: regurgitation, dysphagia, dyspnea/tachypnea.
  • Diagnosis: radiography, endoscopy, fine needle aspiration biopsy Fine-needle aspirate, pleural fluid cytology Pleural fluid: cytology.
  • Treatment: lymphoma   →   chemotherapy Chemotherapy; general principles; thymoma   →   surgery may be feasible.