thoracotomy in cattle & horses

RIB RESECTIONINDICATIONS & PROCEDURE

Dane Tatarniuk, DVM

Question 1

What are the two most common indications for rib resection?

Question 1

What are the two most common indications for rib resection? Pericarditis Pleuritis / Pleuropneumonia

Pericarditis more common indication in bovine

Pleuritis more common indication in equine

Pericarditis

Etiology Traumatic reticulitis

10cm between reticulum & pericardium Wire, nails, etc. Pointed objects 5 to 14cm in length

Trauma to external chest Cardiac neoplasia

Lymphoma

Pericarditis

Pathophysiology Bacteria inoculation septic inflammation

increased permeability fluid exudation influx neutrophils & fibrin

Fibrin bridges within 3 days Collagen replaces fibrin by day 6 Extensive fibrosis by 1 month Constrictive & restrictive pericarditis

Pericarditis

Clinical symptoms Jugular vein distension Brisket edema Submandibular edema Cardiac abnormalities

Pericarditis

Diagnostics Auscultation

Splash heart beats Muffled heart sounds

Ultrasound 4-6th intercostal spaces, level of elbow Effusion : anechoic Exudate : granular, waving strands Thickened sac : organized fibrin, collagen

Radiographs Cardiomegaly appearance

Pleuritis

Cows Pleuritis with pyothorax

or pleural fluid Daily lavage, maintain

drainage

Question 2

Do cattle have complete or incomplete mediastinum?

Question 2

Do cattle have complete or incomplete mediastinum? Complete

Complete mediastinum Only lung on affected side collapses following

thoracotomy Other lung unaffected Respiration usually stays normal

Horses Incomplete mediastinum Walled off – then OK

Pericarditis

Pericardiocentesis Higher risk Caudal to left elbow, sternum to mid-chest Tie left front forward 18 gauge, 6 inch needle Slowly advance needle Watch for needle to move synchronous with

heart beat Aspirate blood – back up Collect fluid for cytology, culture

Rumen bacteria

Pericarditis

Percutaneous pericardial drain Earlier stages of pericarditis

(mostly fluid, little fibrin) Large bore sterile chest tube Similar insertion as for

pericardiocentesis Egress fluid continuously Ingress lavage daily Pull tube once fluid flushes clear

Thoracotomy

Standing, local lidocaine block

Incision over 5th or 6th rib 6th rib

Preferred - posterior to shoulder

5th rib Adduction of limb during

movement Subcutaneous air under

forearm, scapula More prone to cellulitis

Thoracotomy

Incision started at costo-chondral junction Extend dorsally 20cm Lower than CC junction

Lateral thoracic artery & vein Overlying thoracic muscles incised

Dorsally Latissimus dorsi muscle Serratus ventralis muscle

Ventrally Pectoralis profundus muscle Aponeurosis of obliquus externus

abdominis muscle

Thoracotomy

Periosteum incised by scalpel Periosteum retracted cranially & caudally

with periosteal elevators

Thoracotomy

Gigli wire placed 18cm above CC junction Transect Rib wide and thin Disarticulate rib at CC junction

Thoracotomy

Incise pleura Carefully

Exteriorize pericardium and suture to skin edge Same principle as

rumenostomy Can drain pericardial fluid with

needle, suction Incise pericardial sac Manually remove fibrin, clots Lavage sac liberally with

saline Leave open or close with drain

Thoracotomy

Post-operative Cover thoracotomy site with

sterile towel or combine roll Held in place with umbilical

tape Broad spectrum antibiotics Incision examined, flushed

daily Wound kept open as long as

fetid material egresses Can take wound up to 1

month to close

Prognosis

Cattle 15% survival for pericarditis 71% survival for pleuritis

Horses 88% survived surgery 46% returned to intended use

QUESTIONS ?