Thoracic wall

Question 1

Wha flaps can be based on the thoracodorsal artery?

Answer 1

• Thoracodorsal axial pattern flap
• Composite musculocutaneous flap incorporating latissimus dorsi

Question 2

What muscle attaches to the manubrium?

Answer 2

Sternocephalicus muscle

Question 3

What can be used as landmarks during an IC thoracotomy?

Answer 3

• Ribs - finger can be placed uder latissimus to count back from first rib
• Scalenus - attached to 5th rib

Question 4

What muscle is a landmark for the internal thoracic artery?

Answer 4

Transverse thoracic muscle (travels dorsal to muscle)

Question 5

How many intercostal arteries are present?

Answer 5

12 (ribs 1-12)

Question 6

Where do the internal thoracic arteries arise from?

Answer 6

Left and right subclavian arteries

Question 7

What structures can be damaged during a cranial median sternotomy?

Answer 7

• The brachiocephalic truncks and cranial vena cava (Sit right below the sternum and can become collapse during retraction resembling connective tissue)
• Brachiocephalic trunks form from the internal jugular vein and brachial vein. Brachiocephalic trunks then combine to form cranial vena cava in cranial mediastinum

Question 8

What form of IC thoracotomy closure has been associated with less post-op pain?

Answer 8

• Transcostal suture rather than circumcostal

Question 9

List options for approaching the thorax

Answer 9

• Intercostal thoracotomy
• Rib resection thoracotomy
• Median sternotomy
• Xiphoid resection thoracotomy
• Transsternal thoracotomy
• Transdiaphragmatic thoracotomy
• Paracostal approach
• Thoracoscopy

Question 10

What vessels will be encountered during approach for a median sternotomy?

Answer 10

• Perforating branches of the internal thoracic artery and vein when seperating the pectoral muscles

Question 11

What instruments can be used to perform a median sternotomy?

Answer 11

• Reciprocating saw
• Osteotome
• Special sternal saw
• Sternal splitter
• Bone cutters

Question 12

Where are the sternal LNs located?

Answer 12

Where the internal thoracic arteries meet the transverse thoracic muscle

Question 13

Why is an alternating figure-of-8 pattern beneficial for closure of the sternum?

Answer 13

• Avoids distraction of the dorsal or ventral edge
• Maximises boney contact
• Reduces pain
• Facilitates healing

Question 14

What vessels may bleed during a transdiaphragmatic thoracotomy?

Answer 14

Branches of the phrenic artery

Question 15

What can the paracostal approach be used for?

Answer 15

• Right sided for accessing thoracic duct, cisterna chyli and aorta
• Adrenalectomy
• Migrating FBs for abdominal and thoracic exploration

Question 16

What are the 2 broad options for thoracoscopy?

Answer 16

• Intercostal
• Paraxyphoid

Question 17

What breeds are predisposed to pectus excavatum?

Answer 17

• Burmese and Bengal cats

Sternum and caudal ribs fail to gro normally, possible due to shortened or hypoplastic diaphragm, resulting in concave abnormality of the caudal sternebrae

Question 18

How is pectus excavatum treated?

Answer 18

• External splinting in young animal with compliant sternebrae
• Older animals may need an internal splint (VCP) or osteotomy of deformed sternebrae and costochondral junctions with external splinting

Question 19

In what breed has a sternal cleft been described?
Along with what other congenital defects?

Answer 19

• GSD
• With PPDH and cranial abdominal hernia

Question 20

What is a “step” sign on TFAST?

Answer 20

Indicates a discontinuity of the parietal pleura. Can signify IC muscle tear or rib fracture

Question 21

In what animals with thoracic bite wounds should surgery be recommended?

Answer 21

All those with rib fractures, pulm contusion or pneumothorax (according to a study)

Ongoing haemorrhage, pneumothorax or sepsis are indications for surgical exploration

Question 22

How can multiple laceration of the IC muscles be apposed?

Answer 22

Basket-weave pattern

Question 23

List the most common thoracic wall neoplasias

Answer 23

• Chondrosarcoma
• OSA
• FSA
• Other spindle cell tumours (haemangiopericytoma, PNST, Schwannoma)
• HSA infrequent
• MST

Question 24

What are the recommended margins for thoracic wall tumours?

Answer 24

At least 3cm

Question 25

What is considered the maximum thoracic wall resection for adequate reconstruction?

Answer 25

6 ribs

Question 26

List options for sternal reconstruction

Answer 26

- Deep pectoral muscle flaps - Sanwiches of mesh and PMMA - Kiel bone

Question 27

What muscle flaps can be used for thoracic wall reconstruction?

Answer 27

- Latissimus dorsi - External abdominal oblique - Transversus abdominis - Diaphragmatic advancement (ribs 8-13) (may require caudal lung lobectomy)

Question 28

List options for reconstruction with commercial products

Answer 28

- Polypropylene mesh - PTFE mesh/sheet ($$, strong and occlusive) - Polyglactin mesh (absorbable, good for infected sites) - Porcine SIS Infection rates with polypropylene mesh 0-5.7%. Can be minimised by covering with well vascularised tissue (omentum, muscle)

Question 29

How often should the thoracostomy tube be suctioned in the post-op period? When is pleural effusion most common after thoracic wall reconstruction?

Answer 29

- Suctioned every hour until 3 consecutive negative results have been obtained. Then every 4 hours for 12 hours - Pleural effusion after reconstruction within forst 48hr and then declines sharply within 4-5 days