Page 148 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 11 · Thoracic wall anatomy and surgical approaches

been a problem in animals with six or fewer ribs resected,
the potential for hypoventilation may be greater following
VetBooks.ir wall dynamics. The P aCO 2 should ideally be <45 mmHg,
chest wall resection as the animal adapts to new chest
although most animals do not need mechanical ventilation
unless the P aCO 2 is >55–60 mmHg or there is severe respir-
atory acidosis. Partial reversal of pure opioids with low-
dose butorphanol or low-dose naloxone can help with
opioid-induced hypoventilation whilst maintaining anal-
gesia. Arterial blood gases should be measured every 2–6
hours initially until the animal is adequately oxygenated and
ventilating; every 6–12 hours thereafter is usually adequate.
Pulse oximetry may be useful to monitor oxygenation, but
can be difficult in the awake patient.

Surgical approaches (a)

Lateral or intercostal thoracotomy
A lateral or intercostal thoracotomy is the standard
approach for many intrathoracic diseases and provides
good exposure for a specifically defined region (Figure 11.3).
See Operative Technique 11.1 for a step-by-step guide to
performing a lateral thoracotomy.
Access to structures not in the immediate area of
the thoracotomy is limited and, as a general rule, an inter-
costal thoracotomy allows access to approximately one-
third of the ipsilateral thoracic cavity (Orton, 2003;
Moores et al., 2007). Although rarely required, exposure
can be increased by approximately 33% with dorsal and
ventral osteotomies of the rib either cranial or caudal to
the intercostal incision. Closure of the intercostal thora-
cotomy is achieved by placement of circumcostal (see
Operative Technique 11.1) or transcostal sutures (Figure
11.4). In one study, the intercostal nerve was entrapped
by circumcostal sutures in 70% and 100% of cases when
the blunt and the sharp end, respectively, of the needle
was passed around the caudal rib. In the same study, it
was shown that dogs whose intercostal thoracotomies
were closed with circumcostal sutures showed signifi-
cantly more pain and had significantly greater require-
ments for fentanyl in the first 24 hours postoperatively (b)
than dogs whose ribs were closed using a transcostal Intercostal thoracotomy closure using a transcostal
technique (Rooney et al., 2004). 11.4 technique. (a) Holes are drilled into the mid-body of the caudal
rib with a small intramedullary pin or large Kirschner wire. Note that the
underlying lungs are being protected from iatrogenic trauma with a
Access required Surgical approach moistened laparotomy sponge. (b) Once the hole is drilled in the caudal
Trachea Right 3rd to 4th intercostal space rib, suture material is passed around the cranial rib and through the hole
in the caudal rib. Following preplacement of the transcostal sutures, the
Patent ductus arteriosus Left 4th intercostal space sutures are used to approximate the ribs by an assistant while the
Ligamentum arteriosum Left 4th intercostal space surgeon ties the knots.
Lung lobectomy Right or left 5th or 6th intercostal space
Pericardectomy Right or left 5th intercostal space Complications
Pulmonic stenosis Left 5th intercostal space Short-term complications are reported in up to 47% of
Oesophagus: cats and dogs following lateral intercostal thoracotomy
• Cranial Left 4th intercostal space (Moores et al., 2007). Haemorrhage, pain, air leakage,
• Caudal Left 9th intercostal space seroma, infection, wound dehiscence, thoracic limb
Thoracic duct: lameness and re-expansion pulmonary oedema are all
• Dog Right 9th intercostal space potential complications. Haemorrhage is most often
• Cat Left 9th intercostal space caused by inadvertent trauma to the internal thoracic
Caudal mediastinal mass Left or right 9th intercostal space artery during the approach or closure of an intercostal
thoracotomy (Bonath, 1996). Postoperative air leakage,
Cranial mediastinal mass Cranial sternotomy
which can manifest as pneumothorax, pneumomedi a -
Hepatic surgery Caudal sternotomy s tinum or subcutaneous emphysema, is caused by
ecommended surgical approach for a defined surgical problems with either the thoracotomy closure (such as
11.3
procedure or to reach a specific anatomical location. failure to achieve an airtight closure, incisional dehiscence,

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