This document discusses various approaches and techniques for performing thoracotomy in animals. The appropriate approach depends on factors such as the type of lesion, the animal's condition, and the shape and size of the thorax. Common techniques described include intercostal incision, rib resection, split rib technique, and median sternotomy. Proper closure methods are also outlined for each technique. The document also provides details on heartworm disease, its pathogenesis, diagnosis, and treatment options such as melarsomine dihydrochloride administration or surgical removal of worms via ventriculotomy or through the right atrium.

1. Thoracotomy

2. Approaches depends
upon following factors

3. Factors
 Lesion type: DH, lobectomy,
pericardiotomy, thoracocentesis
 Condition of the animal- whether an
early
diagnosed
- withstand extensive
sternotomy(splitting of sternum)/
Intercostal incision should be taken
up

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

5. 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.

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

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

8. 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

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

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

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

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

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

16. 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

17. 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

18. Transabdominal
 Other approaches like transabdominal to
repair DH- paracostal incision
 Heart worm disease:
-dirofilaria immitis
-Mosquitoes- vectors
-Dog- Primary reservoir

20. Heart worm disease:
-3rdstage larva-
infective- 2-3
weeks- mosquito
mouth parts
-Penetrate skin-
susceptible animal-
3m- immature
worms – reach
right side of heart-
obtain full size-
15-35 cm –
5-6months- live for
>5years- non-
infective
microfilariae

21. Heart worm disease:
-adult worm – pulmonary trunk-less no. in
rt. Ventricle- but found in rt. Atrium and
caudal vena cava in heavily infested
animal
• -severity based on
3. No. of worms and location
4. Host immune response
5. Duration of infection

22. Heart worm disease
 Pathogenesis:
 Adult worm causes mechanical irritation of
intima and pulmonary arterial walls- CHF
 Glomerulonephritis- immune complexes
 Pulmonary inflammation and edema
 Symptoms: coughing, exercise intolerance,
dyspnoea, cyanosis,wt.loss despite good
appetite hemoptysis, syncope, epistaxis and
ascites

23.  Diagnosis:
 Antigen detection test
 Right ventricular hypertrophy patterns are
seen
 Detection of microfilariae in routine blood
examination- failure to detect- doesnot
rule out- presence of microfilariae in
heart- go for concentration technique-
count / ml of blood – 1000 MF=1 adult
worm
 5-10% dogs – adult worm- no detectable
circulating MF- eosinophillia is suggestive

24.  Mild cases- RG appearance- normal
 Angiocardiograms- linear filling defects –
branches of pulmonary artery
 Moderate and severe infections- RG-
dilatation of rt. Heart enlargement and
dilatation of pulmonary trunk and its
arteries

25.  Splitting
of second heart sound-
suggestive of pulmonary hypertension-
confirmed by direct cardiac catheterization
–measurement of rt.ventricular/
pulmonary artery pressure
 Treatment :
1.Melarsomine dihydrochloride @ 2.5 mg/kg
deep i.m.
2.Ivermectin

26. 3. Diethyl carbamazine @ 2.5 mg/ lb
b.w.daily -10 days-1month
4. 6 weeks after-disappearance of
clinical signs- dithiazanine iodide
(dizan)2-3mg/lb orally- kill the
microfilariae-7 days
5. Digoxin and diuretics are given in
CHF

27. 3. Restrict exercise- to reduce thrombosis and
endothelial damage
4. Class IV dirofilariasis – Caval syndrome- vena
cavae syndrome -extreme infestation- sudden
onset- collapse with haemoglobinaria and
respiratory distress
5. Surgical removal –questionable- suggested
that – dogs- with less than 50 worms- can
tolerate chemotherapy

28. Puncture ventriculotomy:

29. Puncture ventriculotomy:
 Apply a purse string
suture- pass an
alligator foreceps – in
rt. Ventricle-
repeatedly introduced
and taken out while
hemorrhage is
controlled by purse-
string suture

30. Through median sternotomy-from right
atrium and orifice of tricuspid valve
and caudal vena cava to save the life
of the dog.

31.  Rigid / flexible alligator forceps/
intravascular retrieval snare- via
rt. Jugular vein with fluoroscopic
guidance- pass the instrument
untill worms are no longer
retrieved
 Fluid therapy