surgical approaches to thorax in small animals

Thoracotomy

surgical incision of the chest wall.

SURGICAL ANATOMYThe thoracic cavity of dogs n cats are compressed laterally so greatest dimension is DV.

Intercostalisexternus

Rectusabdominis

Obliquus externusabdominis

Rectusthoracis

Scalenusdorsalis

Serratusventralis,

Serratus dorsalis cranialisObliquus internusabdominis

Serratus dorsaliscaudalisLongissimus

thoracis

Levator costae

Intercostalis internus

Intercostalisexternus

SURGICAL APPROACHES

Intercostal Thoracotomy

Rib Resection Thoracotomy

Median Sternotomy

Transsternal Thoracotomy

Special Considerations: In animals with respiratory dysfunction, oxygen may be

administered.

All animals with open chest cavities require intermittent positive pressure ventilation (including those with diaphragmatic hernias).

High ventilatory pressures should be avoided in patients with chronically collapsed lung lobes, pneumonia.

Thoracotomy procedures often cause substantial pain, and postoperative analgesic therapy is indicated.

Intercostal Thoracotomy

Standard approach

Excellent access to immediate structures

Complications – uncommon, if airtight closure

3rd to 10th ICS

Lateral radiograph

Finochietto retractors

THORACIC STRUCTURE LEFT RIGHT

Heart and Pericardium

PDA, Persistent Rt Aortic Arch

Pulmonic Valve

4,5

4 (5)

4

4,5

Lungs

Cranial lobe

Intermediate lobe

Caudal lobe

4-6

(4) 5

5 (6)

4-6

(4) 5

5

5 (6)

EsophagusCranial

Caudal 7-9

3,4

7-9

Caudal Venacava (6-7) 7-9

Thoracic DuctDogCat

(8-10)

8-10

8-10

(8-10)

Thoracostomy Tube PlacementMake an incision overthe dorsal third of the intercostalspace.

Tunnel the tube withtrocar - tipped stylet cranioventrally

Tilt the tube perpendicularto the thoracic wall, Hit the end of the tubeto pop it through the intercostal spaceand pleura

advance the tubecranially into the thorax

Clamp the tube once thestylet is partially retracted

Adjust the tube position sothat the tip is at the level of the secondintercostal space before securing it inplace.

Lateral Rib Resection Thoracotomy

A wider exposure of the chest (eg : removal of large masses)

Increased time & less secure closure

Infrequently used in small animals

Median Sternotomy

Entire thorax view

Spontaneous pneumothorax /pericardiectomy/ exploratory thoracotomy

Access to dorsal thoracic cavity is limited

Oscillating bone saw/ chisel/ osteotome

Transsternal Thoracotomy IC thoracotomy extended through sternum and

continued to other side’s ICS

Extensive exposure of specific region

Infrequently used

7th ICS - DH

1. PECTUS EXCAVATUM Inward concave deformation of caudal sternum and

costal cartilages

Retarded growth, dyspnoea, exercise intolerance, vomiting, cyanosis

Sx indicated if Cardio pulmonary effect is v severe

Multiple chondrotomy, excision of malformed costal cartilages, sternum struts, external splinting

2. RIB DEFORMITIES Missing ribs

Fused ribs

Multiple ribs

Malformed Ribs

Sx –if restricted ventilation & paradoxical respiration

3. METABOLIC BONE DISEASES Primary parathyroidism

Hypervitaminosis

Cartilage exostosis

Tx: According to underlying cause

4. INFECTION Bite, lacerations, FB Infection. Check pyothorax

before tx.

Tx: Drainage, Debridement

Osteomyelitis Partial sternectomy

FB Fistulous tract Contrast fistulogram excision

5. TRAUMA Internal injury!

Tx: Small wounds: standard

Open wound upto pleura seal with petroleum based gauze

Open chest wound pleural evacuation & stabilisation

IC muscle rupture -> closure like thoracotomy

IC vessel rupture

Simple non displaced rib # - rest & chest bandage

Unstable rib # : Internal fixation

Flail Chest : stabilisation, circumcostal suture, splint

6. NEOPLASIA Skin / sc benign , lipomas

Osteosarcoma, chondrosarcoma, fibro sarcoma, haemangiosarcoma

Internal thoracic wall –considered malignant

Neoplasms of rib – Primary malignant

Dx- Radiograph – osteolysis, extra thoracic soft tissue masses, mineralization, biopsy

Tx: Resection. Prognosis poor for osteosarcoma