Thoracotomy in animals

Thoracotomy in animals is the surgical incision of the chest wall to enter the thoracic cavity of animals. it is a important surgical procedure for surgical affections of thoracic cavity.

The normal negative pressure of the pleural space will be lost on account of air entering the pleural cavity. thus there will be increase in the pressure in the pleural cavity, which overcomes the pressure of the air inside the lungs leading to lung collapse.

Prerequisites for thoracotomy

Since the normal negativity of the thorax is altered by the presence of air in the thoracic cavity, Facility for mechanical ventilation of the lungs is a must before opening the thorax.

This is done using a ventilator which provides intermittent positive pressure ventilation.

Thoracotomy in Dogs

There are various thoracic cavity approaches for thoracotomy in dogs-

1. Intercostal incision
2. Intercostal incision with resection of adjacent rib
3. Rib resection
4. Median sternotomy

Intercostal incision

• Incise cranial to the rib since the intercostal vessels courses the rib caudally.
• A self retaining rib retractor should be used for exposure of the thoracic cavity
• For closure, place series of interrupted sutures around adjacent ribs
• Hold the ribs closer and tie the sutures individually
• A simple continuous suture in the intercostal muscles seals the incision against air leaks

Intercostal thoracotomy

• Lateral recumbency
• Select the site for incision
• Locate appropriate intercostals space
• Sharply incise the skin, subcutis and cutaneous trunci
• Deepen the incision through lattisimus dorsi, transect the scalenus and pectoral muscles
• Separate muscle fibers of serratus ventralis
• Incise the external and internal intercostal muscles
• Penetrate the pleura
• Extend the incision dorsally and ventrally for desired exposure (Avoid incising internal thoracic vessel as they course subpleurally near the sternum).
• Use Finochitto rib retractor to spread the rib
• Closure of the thoracotomy is by preplacing heavy monofilament sutures around the adjacent rib and approximating the ribs before tying the sutures.
• Negative pressure of the pleural cavity should be re-established while tying the last suture of the thoracotomy incision.
• This is done by inflating the lungs fully so that all air is emptied from the pleural cavity.
• The last suture should be tied when the lung is in full inflation to establish negative pressure in the pleural cavity.

Rib resection

• Incise directly over the rib
• Incise the periosteum longitudinally and strip off the periosteum completely from the rib
• Resect the rib at the proximal end and then disarticulate it at the constochondral junction
• Incise the exposed periosteum of the resected rib and the pleura to enter the thoracic cavity
• Closure is done by suturing the pleura and periosteum together, followed sequentially the subsequent layers

Median sternotomy

• Dorsal recumbency
• Incise skin on midline of the sternum
• Expose sternum by incision and dissection of the overlying muscles
• Transect the sternebrae longitudinally on the midline to enter the thoracic cavity
• Retract the edges with a Finochitto rib retractor
• Closure is to be done with wires or heavy sutures place around the sternebrae
• Establish negative pressure while tying the last knot

Recommended site for thoracotomy in dogs

Organ	Intercostal space	Side
Heart	4th or 5th	Left or Right
Lungs	4th to 6th	Left or Right
Cranial Oesophagus	3rd or 4th	Left
Caudal Oesophagus	6th to 9th	Left or Right

Thoracotomy in Bovines

There are various thoracic cavity approaches for thoracotomy in bovines-

1. Intercostal incision
2. Rib resection
3. Split-rib technique

Intercostal incision

• Incise cranial to the rib since the intercostal vessels courses the rib caudally.
• A self retaining rib retractor should be used for exposure of the thoracic cavity.
• For closure, place series of interrupted sutures around adjacent ribs.
• Hold the ribs closer and tie the sutures individually.
• A simple continuous suture in the intercostal muscles seals the incision against air leaks.

Rib resection

• Incise directly over the rib
• Incise the periosteum longitudinally and strip off the periosteum completely from the rib
• Resect the rib at the proximal end and then disarticulate it at the constochondral junction
• Incise the exposed periosteum of the resected rib and the pleura to enter the thoracic cavity
• Closure is done by suturing the pleura and periosteum together, followed sequentially the subsequent layers

Split-rib technique

• Expose the rib and longitudinally incise over the rib at its centre
• Section the rib transversely at either ends of the primary incision to approach the thoracic cavity
• Closure of the rib incision is done by interrupted sutures

Site for thoracotomy in bovines

Procedure	Site
Thoracentesis	5th to 7th
Pericardiocentesis, Pericardiotomy, Pericardiectomy	5th intercostal space or 5th rib resection
Diaphragmatic herniorrhaphy	6th or 7th rib
Transthoracic oesophagotomy	8th rib
Diaphragmatic abscess	7th rib
Lobectomy	4th or 5th rib