Thoracic surgery involves approaches like intercostal thoracotomy, rib resection, split rib, and median sternotomy to access the thoracic cavity for conditions like diaphragmatic hernia and abscesses. Key anatomical considerations for these approaches include the musculature, vasculature, and respiratory physiology of the thoracic wall and pleural spaces. Common indications for thoracic surgery are penetrating wounds, foreign bodies, fractures, abscesses, and tumors affecting the lungs, heart, or pleural spaces.

1. Thoracic Surgery

2. History
 Reports on thoracic surgery are available as early as 1960 for the treatment
of traumatic pericarditis.
 Complete mediastinum in cattle so surgeons took advantage of
mediastinum thoracic- divides the thorax into right and left cavities.
 So unilateral thoracotomy was successful unless there is an injury to
mediastinum
 About the LA in india due to sentiments the surgery is undertaken and
usually not cost effective but in other countries it is not so so a scanty
literature is available as regards to large animals

4. The cavum mediastina serosum, or Sussdorf space (see Fig 4), is a mediastinal serosal cavity that develops
in the foetus from the cranial pneumatoenteric recess in the primary, united TA cavity. During foetal growth,
the cranial part of the Sussdorf space in the thorax becomes separated from the abdominal cavity and
omental bursa by the development of the septum transversum

5.  The mediastinum completely separates the right and left pleural
cavities.
 The mediastinum is the region of the thoracic
cavity located between the two lungs. Included within
the mediastinum are numerous structures, ranging from the heart
and great vessels (aorta, superior and inferior venae cava) to lymph
nodes and nerves.
 The pleura which is a serous memberane- single layer of
mesothelial cells and overlying stroma of lymphatics and BV

6.  Cavity Contain two complete serous sacs
around lungs. The junction of the two
sacs near the midline of the thorax forms
a double layer of pleura called the
mediastinum thoracic(divides the thorax
into rt and lt cavities). Dead space
between parietal and visceral pleura is
pleural sac.contains serours fluid to
reduce the friction
 The space created by pleural
reflection(towards diagphragm) when not
occupied by the lung is called
costodiagphragmatic recess

7.  Pleural cupula: right side in ruminants-pleural
cavity extends cranially to the first rib-may be
accidentally punctured during surgery or by
penetrating wounds.
 Indications of thoracic surgery- diaphragmatic
hernia, diaphragmatic abscess, penetrating
wounds, foreign bodies in the thoracic cavity,
fractured ribs, localized lung abscess,
bronchial fistula, suppurative or constrictive
pericarditis, pneumothorax or hydrothorax,
thoracic tumours, obsturciton in the thoracic
part of the oesophagus.

8. Anatomical considerations
 13 pair of ribs, 13 vertebrae, 9 sternebrae (camel 8, since 4 asternal
pair of ribs, costal arch is 9-12 costal carilages whereas 10-12 in
other animals), costal arch, xiphoid cartilage, manubrium
 Each rib forms two synovial costoverterbral articulations with
corresponding vertebra and first nine form the synovial articulations
with the sternum
 The movement afforded by the synovial joints, curvilinear shape of
the cavity and costal cartilages enable the expansion and relaxation
of the thoracic cavity

10.  Muscles of the thoracic wall invaded while lateral thoracotomy
between 5-8th rib---skin- cutaneous muscle of the trunk, latissimus
dorsi, serratus ventralis, external intercostal and internal intercostal

11.  The intercostal arteries and veins arise from aorta and
azygous vein.
 Course ventrally along the caudal border of each rib
and merge with the internal thoracic artery and vein
lateral to the sternum and internal to the costal
cartilages. (intercostal vessels and nerves on cranial
border are also present)
 The intercostal nerves- ventral branches of thoracic
nerves and join the intercostal vessels.

12. Physiology
 Thoracic wall has active and passive
structures- bucket handle motion
 Passive structures: characteristic compliance
and change according to the active changes
in pleural pressures
 Passive will inward coil or outward coil
depending on the thoracic pressure (from
inside)
 V0 is unstressed volume at which passive
elastic structures of the thoracic wall are
relaxed. When the thoracic vol is less than
V0 then an outward passive recoil is
created. And when the thoracic vol is
greater than V0 an inwards passive recoil is
created. The balance of thoracic pressure
(inward elastic recoil of the lung exactly
balances the outward passive recoil of the
wall is functional residual capacity of the
lung)

13.  Total pulmonary compliance is added
compliance of thoracic wall and
lungs
 Abnormalities in the total pulmonary
compliance results from changes in
lungs compliance or thoracic wall
compliance.
 Pulmonary diseases that reduce the
lung compliance (restrictive lung
diseases) decrease the functional
residual capacity by increasing
inward elastic coiling of the lungs
 Diseases that decrease the thoracic
wall compliance- increase the
functional residual capacity of the
lungs by increasing outward recoiling
of the thoracic wall

14. https://www.youtube.com/watch?v=hp-gCvW8PRY
 Loss of functional attachment between lungs and thoracic wall
causes inward recoiling of the lungs and outward recoiling of the
wall to its V0. This explains the sprung appearance in pneumothorax
 Contraction of diaphragm and inspiratory muscles cause a negative
pressure and inspiratory airflow-lungs expansion
 The inspiratory muscle (external intercostals and diaphragm)
transthoracic pressure should be greater to over come the airway
resistance of lungs and inward elastic coil of the thoracic wall. The
passive elastic wall assists in inspiration until the volume exceed V0

15.  The pulmonary diseases that increase the airway resistance or
decrease lungs compliance require generation of higher
transthoracic pressures by active respiratory bellows and distressed
respiration.
 Expiration is a passive during quiet breathing---elastic recoil of the
lungs and passive inward movement of thoracic wall while the
thoracic vol is greater than V0
 Paradoxical movement of the thoracic wall- paralysis(low cervical
spinal injuries) the diaphragmatic contractions force exceeds the
passive outward recoil of the wall and inward movement of thoracic
wall during inspiration---reduces the effectiveness of ventilation
 (Flial chest (two or more ribs fractures) and pectum excavatum

16. General considerations
 Knowledge of special instruments and cardiopulmonary physiology
 Preoperative and postoperative assessment
 Anemia and hypovolaemia because anesthesia would aggrevate the problem of
insufficient oxygenation and circulation
 The lungs should be auscultated and survey radiographs to overrule the pulmonary
diseases
 General anesthetics should be carefully selected (General anesthetic induction and
maintainence with inhalant anesthetic )
 Maintenance of adequate ventilation is a prerequisite in thoracic surgery

17. Transport of gases
 Inspiration: pleural cavity is enlarged and intrapleural becomes
negative so lungs fill more and more with air----so alveolar pressure
become subatmospheric---pressure gradient is established---air
enters the alveoli. During expiration the chest and lungs return to
resting----reverse gradient
 There is a negative pleural pressure in normal animals. When the
thoracic cavity is opened – atmospheric air enters- pleural cavity—
abolish the negative pressure—lungs tissue collapse due to their
natural elastic property—mediastinum deviates towards the
unopened thoracic cavity—causes partial collapse of the unexposed
lung.

18. How the intrapleural pressure affects the cardiac output
 When the intrapleural is negative—during inspiration—promotes the
venous return to right side of heart—at the end of expiration intrapleural
returns to the resting value---the rate of flow of venous return is
decreased but maintained due to peripheral/CVP gradient.—but when
thoracic cavity is opened---intrapleural pressure increases and Peripheral
/CVP gradient disappears- less venous return—less filling pressure of
ventricles—reduced cardiac output
 Therefore need to IPPV- mechanical respirators commercially available-
maintain the rate between 12-16/ min is suitable
 Expiratory phase should be longer than the inspiratory phase to allow
passive deflation of lungs and adequate clearance of carbondioxide.
 After surgery the maintainence of negative pleural pressure is ensured
by practicing full expansion of the lungs when a small incision is left for
insertion of catheter through which suction and drainage is enabled—
inflate the lungs to full ---suck out the air---and close the incision by
removing the catheter with a jerk and prepalaced matress sutures to
prevent any further entry of air into the thoracic cavity.

19. Postoperative
 Observe the patient for spontaneous return of the
normal respiration after the ventilator is disconnected
 The endotracheal tube is removed after return of
swallowing reflex
 Assisted to return to sternal recumbency as soon as
possible(gunny bags stuffed supported)
 Analgesics and antibiotics
 Transient radial paralysis due to lateral recumbency
should be taken care
 If transudation is excessive causing marked dyspnoea
then go for drainage
 https://www.youtube.com/watch?v=aFB036O_U9o

20. Approaches depends
upon following factors

21. Factors
1. Lesion type: DH, lobectomy, pericardiotomy, thoracocentesis
2. Condition of the animal- whether an early diagnosed
3. - withstand extensive sternotomy(splitting of sternum)/
Intercostal incision should be taken up
4. The site to be approached
5. Technique preferred by the surgeon (cost effectivity, availability of
facilities, risk of the animals, shape and size of the thorax etc)
 Intercostal thoracotomy
 Rib resection
 Split rib
 Sternotomy
 Paracostal (to repair diaphragmatic rents/drain diaphragmatic
abscess/ hernia etc)
 Transternal thoracotomy: combination of intercostal and sternal to
have more exposure of the thoracic cavity
(7th intercostal space for DH )

22. Sites for surgical approach to the thoracic cavity in
bovines

23. Factors
 Shape and size of thorax
Less capacious- more manipulation-
sternotomy
More capacious – more manipulation-
intercostal is sufficient/ rib split/ rib
resection

24. Techniques of thoracotomy
 Intercostal
incision:
• Cranial to the rib –
intercostal vessels are
located caudally
• Extend the incision to
desired length
• A self retaining rib
retractor is used for
adequate exposure of
the intrathoracic
organs.

25. Techniques
• Serratus ventralis
dorsally and external
abdominal obliqus
ventrally – after
incising the facia.
Separate the fibres to
expose external
intercostal muscle.

26. Thoracotomy
• During expiratory
pause the
intercostal m and
pleura – incised-
midway between
the ribs

27. Closure
 Chromic
catgut/nylon –
cranial and caudal to
incision- ribs
opposed with towel
clamps
 Adv: simple&quick
Dis: insufficient- heart
& great vessels
- Rib fracture when
held with rib
retractor

30. Technique
 St. incision- over
rib- reflect
periosteum- lat.
and medial

31. Rib resection
 Periosteal
elevator- used
to separate the
periosteum
medially and
laterally

33. Closure
 Series of
interrupted
sutures placed
about 1 cm
apart- lateral
and medial
periosteal
surfaces- cranial
and caudal edge
of incision
 Adv: -good
healing
 No gap
 Disadv: lot of
skill
 Time consuming
 Weak point-
absence of rib

34. Split rib technique
 Expose the rib
 St. longitudinal
incision- center-
oscillating bone
saw.
 Rib is sectioned-
transversely at
either ends- of
primary incision

35. Split rib technique
 Adv: maximum
exposure-
without
involvement of
rib retractor
 Closure is simple
and quick-
interrupted
stainless steel
wire

36.  Disadv:
Dent formation along margins
 Sternum splitting incision (Median
sternotomy)
 Required for extensive manipulation-
cardiac defects and associated structures
 Animal on dorsal recumbency
 Skin incision- manubrium to xiphoid
 Sternum split- chisel/splitter/ electrical
saw
 Don’t sever vessels – either side of
midline

37. Closure
 Drill hole in sternabrae- suture with
monofilament nylon
 Disadv:
-Postoperative pain- discomfort- depth
of respiration is affected
-Inaccurate apposition
-cardiac output is reduced due to
increased CVP

38. Transabdominal
 Other approaches like transabdominal to
repair DH- paracostal incision

39. Transternal thoracotomy

40. Pleural effusions
 Parietal and visceral pleura is continuous moistened with the clear fluid –
gets reabsorbed so that only few ml – in the cavity- contains electrolytes
with small amount of protein and cell- Sometimes abnormal accumulations
– sign of a definitive disease
 The formation and absorption is controlled by starling’s force i.e. Capillary
hydrostatic pressure and colloidal osmotic pressure.
 Normally, fluid formed by parietal pleura is reabsorbed by thevisceral
pleura. Fluid of parietal pleura moves from the blood capillaries --- due to
the parietal hydrostatic pressure A.

41. Parietal pleura Visceral PleuraPleural Cavity
Capillary
hydrostatic
pressure A
Negative
hydrostatic
pressure B
+
Colloid
osmotic
pressure C
Capillary
colloid
osmotic
pressure D
Capillary
colloid
osmotic
pressure D

42. Net pressure
for fluid
A+B+C+D
Movement Absorption
Pleural Fluid formation and reabsorption
The hydrostatic pressure in the systemic capillaries which
supply the parietal pleura is greater than in the pulmonary
capillaries which supply the visceral pleura---so the fluid
moves to visceral pleural

43.  Common in buffaloes and cattle
 It may be pleural or non pleural origin
 Hemodynamic and capilla
ry colloid osmotic changes and inflammatory process –increase the
effusions
 Right sided CHF causes –increased fluid formation
 Reduced pleural absorbtion– increased visceral capillry hydrostatic pressure
associated with left side CHF.
 More production of fluid with less absorption: Liver diseases—less protein
content—decreased colloidal pressure- increased fluid formation
 Inflammation of pleura—increases capillary hydrostatic pressure and protein
leakage---increased pleural fluid formation
 Lymphatic absorption is reduced by inflammatory thickening of pleura
 Hemothorax, chylothorax, pneumothorax or neoplasms
 Difference between transudates and exudates
 Transudates (low colloidal pressure,hypoalbunaemia, high hydrostatic
pressure, increased veonous hydrostatic pressure)
 Exudates: result of inflammatory conditions—increased permeability—fluid
leakage, protein and cells—it may be sterile (neoplasms, chylous effusion,
and hemorhage) or infected (Purulent)

44. Clinical Signs:
 Shallow respiratins, abducted elbows, cough, anorexia, restlessness and
reluctancy to move, pyrexia, pleurisy, brisket edema, distended jugular with
pulsation, muffled heart sounds, pleural friction rub. Affected site dullness
of sound. Pyothorax, haemothorax and hydrothorax should be
differentiated, also DH
 Diagnosis: If brisket edema- DH should be inspected. Plain radiographs
chest—ground glass appearance-obscure the cardiac and Diaphragmatic
silhouttes-
 A distinct horizontal fluid level line on standing RG. Collapse of lung and
shifting of heart and mediastinum due to fluid pressure

45.  Thoracocentesis- physical, cytological and biochemical and culture
sensitivity test