90. Esophagus Flashcards
nerve supply that travels with thoracic esophagus into abdomen
dorsal and ventral vagal trunkscranially: pharyngoesophageal n, recurrent laryngeal nerves, paralaryngeal n, vagal n.
T/Fthe esophagus has a serosal outer layer
FALSEadventitia
diffierence in muscular composition of the esophagus in dogs vs cats
dogs—entirely skeletal musclecats—skeletal muscle and terminates as smooth muscle, terminal portion folds transversely (herringbone)
sphincters of the esophagus
had to ddx anatomicallycranial: cranial esophageal sphincter (made of cricopharyngeal/thyropharyngeal muscles)caudal: lower esophageal sphincter (gastroesophageal junction–hi P)
main blood supply to the esophagus
- cervical esophagus: cranial and caudal thyroid arteries2. thoracic esophagus cranial 2/3: bronchoesophageal artery3. thoracic esophagus caudal 1/3: esophageal branches of aorta and dorsal intercostal arteries4. terminal abdominal esophagus: left gastric artery
3 phases of swallowing
- oropharyngeal (oral (voluntary), pharyngeal (involuntary), pharyngoesophageal/cricopharyngeal): prehend, masticate, make bolus, push through cricopharyngeal sphincter (protect nasopharynx with contraction of palatal/pharyngeal constriction to close, caudal epiglottis reflection and vocal fold adduction to protect airway); final stage is relaxation of muscles while delivering bolus to cranial esophagus2. esophageal: primary peristaltic wave stimulated by dissension from bolus, pushes aborally; second wave will occur if dissension remains in esophagus3. gastroesophageal: muscularis relaxes ahead of the bolus and the bolus is propelled through gastroesophageal sphincter
nerves responsible for oropharyngeal stage of swallowing
5 trigeminal 7 facial9 glossopharyngeal10 vagus12 hypoglossal
in healthy dogs, esophageal transmit time with liquid vs kibble
DEPENDS ON POSITIONING!sternal: 3 (liquid) -4 (kibble) minR lateral recumbency: 7(liquid) –9 (kibble) minfaster in STERNAL
general causes of dysfunction of the esophagus
- mechanical (or anatomic) lesions: FB, tumors, strictures, vascular ring anomalies, intussusceptions, hiatal hernias2. functional (or NM) lesions: hypoperistalsis/aperistalsis3. inflammatory lesions: acute vs chronic
reasons why esophagus has higher prevalence of incisional dehiscence
- lack serosa (heals create fibrin seal and source of stem cells)2. segmental blood supply3. lack omentum4. constant motion5. tension at surgical site
T/Fcan ligate branches supplying thoracic esophagus and it will live
TRUE as long as cervical and abdominal portions are intact due to strong intramural blood plexuses in the submucosaCANNOT ligate cervical and thoracic segments at the same time (necrosis)
surgical approaches to the esophagus
- ventral midline2. cranial median sternotomy3. right and left lateral thoracotomies depending on lesion
suture holding layer of esophagus
submucosa
resection of how much of the esophagus has been associated with an increased rate of dehiscence
resection of > 3-5 cm of esophagus has been associated with increased dehiscence
considerations for a two layer closure in the esophagus
- intraluminal knots simple interrupted of submucosa, mucosa2. extraluminal knots inverting pattern or appositional simple interrupted(can consider simple interrupted or continuous single layer but interrupted is preferred)
what is the maximum cervical and thoracic esophagus that can be resected in experimental dogs
20% cervical 50% thoracicCAUTION: TENSION
method to relieve tension on esophageal R&A
circumferential PARTIAL myotomy of outer muscle layer (to heal by 2nd intention) caution with excessive mobilization due to disruption of the segmental blood supply
methods of esophageal R&A
–simple interrupted closure–end to end stapling devices–biodegradable anastomic ring–esophageal substitution
esophageal patching
omentum, pericardium, SIS, muscle (sternothyroid, longus colli), buccal mucosal graftscan be used to reinforce closure (on-lay)can be used following esophagoplasty after longitudinal division of esophageal stricture (in-lay)
esophageal substitution
if massive resectioncan replace cervical esophagus with inverse tubed skin graft; can also use muscle grafts, gastric advancement for other areas of esophagus to be replacedmultistage procedureMINIMAL clinical experience
in embryos, what are the great vessels derived from
paired dorsal and ventral aortas and the 6 interconnecting pairs of aortic arches (6 brachial arches)arches 1,2 involute3rd arches becomes carotid arteriesleft 4th AA –> adult aortic archright 4th–> right subclavianleft 6th AA–>pulmonary trunk, ductus arteriosus (ligamentum arteriosus)right 6th–>pulmonary artery
7 types of vascular ring anomalies
- PRAA with left LA (most common 95%)2. PRAA with right LA (NO ring, no obstruction)3. PRAA with aberrant LEFT subclavian artery and right LA (artery passes dorsal from the right sided Ao–single ring incomplete stricture)4. PRAA with aberrant left subclavian and Left LA (double ring strictures)5. Double AA (significant tracheal stenosis)6. normal AA (left) with persistent right LA (mirror image of PRAA and left LA–NEEDS A RIGHT LATERAL THORACOTOMY)7. aberrant right subclavian (arising from Ao instead of brachiocephalic trunk and travels dorsal across esophagus–partial ring, may not see clinical signs, but is common)
in PRAA patients with LA, how often is the ligamentum patent (ductus)? And what other abnormality may be present
left cranial vena cava 45%patent ductus 10%other congenital abnormalities 20%
signalment for PRAA
GSD, Irish Setter> 15 kg20% diagnosed by 2 months80% diagnosed by 6 months
