Pulmonary hydatid cysts

The goal of surgical therapy in pulmonary hydatid disease is to remove the cyst while preserving as much lung tissue as possible. The surgical method may be different in the intact (simple) and ruptured (complicated) cysts. The operation has two steps: a) removal of the germinative layer, b) management of the residual pulmonary cavity. Simple cysts are generally removed after needle aspiration or enucleation without needle aspiration.
General principles of the operation�The aim of surgery in pulmonary hydatid cyst is to remove the cyst completely while preserving the lung tissue as much as possible . Lung resection is performed only if there is an irreversible and disseminated pulmonary destruction. Careful manipulation of the cyst and adherence to the precaution to avoid the contamination of the operative field with the cyst content is the imperative part of the operation.

1. PULMONARY HYDATID
DISEASE
Prof. Abdulsalam Y Taha
School of Medicine
Faculty of Medical Sciences
University of Sulaimani
Iraq
https://sulaimaniu.academia.edu/AbdulsalamTaha

2. Pulmonary
Hydatid
Cysts

3. The Cyst
Hydatid disease is a parasitic infection
caused by Echinococcus granulosus. The
cyst lodges most commonly in the liver and
the lungs, respectively. Morphologically,
hydatid cyst consists of three layers and
hydatid fluid. The first layer is the pericyst or
adventitia which is the host tissue formed by
the lung as a reaction to the foreign body
(parasite). The other two layers , the
laminated membrane (external layer of the
cyst) and the germinative layer (inner layer
of the cyst), belong to the parasite( .The cyst
fluid resembles water in appearance which
may contain daughter vesicles.

6. The cysts exist in
different forms: intact or
ruptured, single or
multiple, unilateral or
bilateral, solely located
in the lung or
concomitantly in other
organ lodgments
(especially in the liver).

7. The goal of surgical therapy in
pulmonary hydatid disease is to remove
the cyst while preserving as much lung
tissue as possible. The surgical method
may be different in the intact (simple)
and ruptured (complicated) cysts. The
operation has two steps: a) removal of
the germinative layer, b) management of
the residual pulmonary cavity. Simple
cysts are generally removed after needle
aspiration or enucleation without needle
aspiration.

8. Enucleation cannot be performed in
ruptured cysts. The lung cavity that
remains after removal of the cyst may
be left as it is or obliterated by sutures
from within the cavity in regard to the
size and location of the cyst. However,
the bronchial openings in the cavity
must be closed by sutures in all cases.
Rarely, hydatid cysts can occur in other
thoracic structures such as pulmonary
artery, chest wall or diaphragm. Those
cysts located on the liver dome are
operated by transthoracic–
transdiaphragmatic approach.

9. A perforated hydatid cyst located in the right lower lobe of the lung.
The air is seen between the laminated membrane and the cyst.

10. A computerized tomography of the chest showing 2 intact
hydatid cysts located in the right lower lobe of the lung.

11. A CT appearance of a ruptured hydatid cyst
located in the right parahilar area.

12. Two ruptured cysts located in the right lower lobe of the lung. The
fluid of the smaller one is completely expectorated while the larger
cyst seems still having the fluid. Partial or complete expectoration of
the fluid after cyst rupture is completely related to the presence or
absence of an open bronchiole adjacent to the cyst.

17. The macroscopic appearance of the hydatid cyst in the lung

18. General principles of the operation
The aim of surgery in pulmonary
hydatid cyst is to remove the cyst
completely while preserving the lung
tissue as much as possible . Lung
resection is performed only if there is
an irreversible and disseminated
pulmonary destruction. Careful
manipulation of the cyst and adherence
to the precaution to avoid the
contamination of the operative field
with the cyst content is the imperative
part of the operation. The cysts located
on the liver dome are easily accessible
and resected via right thoracotomy with
the transdiaphragmatic approach.

19. Finding the cyst
Once the chest is opened, the lung is
palpated gently to avoid the rupture of
the cyst. The anesthesiologist deflates
the lung in the operated site and the
surgeon finds the cyst located in the
depth of the lung tissue easily if it is
not very small or if it is located
superficially. The smaller cyst located
within the parenchyma is found by
gentle palpation of the lobe that is
obtained to have the cyst in
computerized tomography of the chest.

21. Covering the adjacent lung with the
towels
Because there is always a risk of
spillage of daughter vesicles into the
operating field during the operation,
the lung should be surrounded by
sterile towels immediately at the
beginning of the operation. Only the
area of the cyst-containing lung must
be in the operating field before any
attempt be made to remove the cyst
or aspirate the cystic fluid

23. Removal of the cyst
The intact cysts are removed in
one of the two ways: removal of
the cyst following aspiration of
the cystic fluid, or by
enucleation of the cyst without
aspiration of the fluid. Ruptured
cysts can only be removed by
aspiration of the cyst content,
then by the removal of the cyst
membrane

25. 1. Removal of the cyst following
aspiration of the cystic fluid. The
intact cysts may contain living
vesicles suspending in the cystic
fluid. A careful aspiration of the fluid
prevents the dissemination of the
vesicles into the chest or to the
bronchus. The aspiration is
performed with a syringe adapted to
a 3-valved aspiration catheter. Ten
percent povidone iodine may be
injected into the cyst through the
same catheter to kill the living
vesicles within the cyst

26. When minimal fluid is left in the cystic
cavity, the needle insertion site is enlarged
and suction apparatus is inserted into the
cyst to aspirate the residual fluid
completely. After the aspiration has been
completed, the edges of the pericyst are
enlarged in an extent so that the laminated
membrane can easily be taken out. The
assistant grasps the edges of the pericyst
and the surgeon takes the laminated
membrane (which is generally disrupted)
out of the cavity

28. 2. Enucleation of the intact cyst without needle aspiration.
Enucleation is performed by removing the intact cyst from
the cystic cavity by a careful dissection between the pericyst
and the laminated membrane. Pericystic layer is incised or
cut superficially until the laminated membrane of the cyst is
seen. This incision is then extended to a certain length so
that the delivery of the cyst is possible. The pericyst is
separated from the laminated membrane patiently by sharp
and blunt dissections. Inflating the lung by the
anaesthesiologist and gentle and adjusted manual pressure
over the surrounding lung by the surgeon assist the delivery
The cyst is delivered over the gauze steeped in povidone
iodine and then taken out of the chest with the gauze.

31. Management of the residual cavity
When the cyst is removed, the
remaining pulmonary cavity is cleaned
completely with sterile gauze and,
observed for the presence of air
leakage. Air leakage can be seen by
direct observation and also by filling
the cavity with sterile saline solution.
The cavity is filled with the fluid only
after closure of the major bronchial
opening (s) has been performed .

33. The simple alveolar air leakage is
not an important issue, which can
easily be managed during the
obliteration of the cavity with
imbrication sutures. The
obliteration (capitonnage) is made
by circumferential imbricating
separated sutures with a 3-0
chromic catgut or a 3-0 coated
polyglactin from within the cavity

35. When two steps of the
resection of the cyst(s) have
been accomplished, the
towels surrounding the lung
are taken out from the chest
using the grasping
instruments. Because the
towels may contain cystic
material, the hands must not
be used in their removal from
the operative field.

37. Transthoracic–transdiaphragmatic
approach to the subdiaphragmatic
hydatid cysts
Not infrequently, thoracic surgeons are
asked for the management of hydatid
cysts located at the upper part
(subdiaphragmatic location) of the liver.
A thoracotomy provides better
exploration and access to the cyst
located in this area when compared to
the laparotomy.

38. The principal of the resection of liver cyst is similar with the
pulmonary cyst; however, there are important technical
differences between the two operations: the hepatic cysts
contain daughter vesicles more commonly than the
pulmonary cysts. For this reason, a scolocidal agent (to kill
the parasite) such as hypertonic saline solution or 10%
povidone iodine must be injected through the diaphragm into
the cyst to prevent the spreading of the living vesicles in the
abdomen or thorax before the opening and removal of the
cyst. The diaphragm is cut using a scissors and its muscle is
separated from the cyst by blunt and sharp dissections with
no pressure over the cyst. When the intracystic pressure has
been lowered, the cyst is opened from the uppermost part of
the cyst and its content is aspirated by a large holed suction
device.

40. Because the cyst contains
numerous daughter vesicles
that are not technically
possible to aspirate with a
suction device or take out by
a grasper, a spoon is used to
evacuate the cavity
completely
A rubber tube is inserted into the cavity
and taken out from the skin under the
diaphragm. The edges of the cyst's
fibrous capsule are closed with mattress
sutures.

42. Removal of the hydatid cysts from the main
pulmonary artery
Very rare, but a highly fatal situation, is the
lodgement of the hydatid cyst in the
pulmonary artery. Main pulmonary artery
must be investigated carefully for the
presence of ‘filling defect’ in every case with
multiple pulmonary hydatid cysts. The
removal of the hydatid cyst is performed with
pulmonary arteriotomy via sternotomy under
total circulatory arrest or cardiopulmonary
bypass.

44. Resection of the hydatid cyst
located on the thoracic wall
The chest wall is one of the
unusual locations of the hydatid
cyst. Because there is no cavity left
after the removal of the cyst on the
chest wall, the surgical technique
includes only the removal of the
cyst.

45. RESULTS
Postoperative complication rate is 0.8–4% for the intact cysts and,
4–6% for the ruptured cysts. The most common postoperative
complications are prolonged air-leak, empyema and, pneumonia due
to the aspiration of cystic content or washing solution through an
open bronchus adjacent to the cyst.
The mortality rate is lower than 1% in the intact cysts and around 2%
in the complicated cysts. The mortality is closely related to the
presence of unrecognized cysts in the central nervous system (CNS)
or in the proximal part of the pulmonary artery. The size of the cyst
is also another factor which maybe associated with the increased
complication rate.
The CNS and the pulmonary arteries must be evaluated before
surgical attempt is made in every case with disseminated
hydatidosis.
Recurrence rate is between 1 and 6%. Adherence to the precaution
to avoid spreading of the cystic material and, the use of albendazole
in selected patients decreases the recurrence rate.
Pulmonary resection (i.e., lobectomy) is necessary in less than 10%
of the patients.

46. Indications for resection in pulmonary hydatid disease
Indication Number of patients %
Huge simple cyst causing lobe destruction 5 38.4
Suspicion of a tumour 1 7.6
Infected ruptured cyst 5 38.4
Hydatid broncheictasis 1 7.6
Life-threatening haemoptysis secondary to
central hydatid cyst eroding pulmonary
vessel. 1 7.6
Total 13 100

47. Pulmonary hydatid cyst is endemic in our
country. It is responsible for most of the
thoracotomies in our practice. In Faisal Haba's
series, surgery for pulmonary hydatid cyst
constituted 25-35% of thoracotomies. Parasitic
infestation by hydatid cyst when complicated is
a common indication for resection in Iraq.
Elhassani reported a 28% of cases treated by
pulmonary resection for pulmonary hydatid cyst
while 20% of patients with pulmonary hydatid
disease required resection in Faisal Haba
series.

48. The treatment for hydatid disease is surgical
removal of the cyst and its contents with
preservation of lung parenchyma. Every trial
should be done to remove as little as possible of
functioning lung tissue in order not to affect
pulmonary functions. Pulmonary resection is
reserved for the simple giant cyst that causes
permanent and irreversible changes in the
affected part of the lung and for the complicated
cyst where infection has caused lung abscess.
Resection is also indicated when there are
multiple daughter cysts within the mother cyst. In
patients with massive haemoptysis or recurrent
suppuration following the removal of the cyst,
resection of the involved part of the lung is
advisable. Bronchobiliary fistula is another
indication for lung resection in PHC .

50. AN 8 YEAR OLD BOY WITH INTACT HC IN LLL

57. To summarize the case:
The diagnosis of intact PHC in an endemic
area is not difficult. Plain radiographic
appearance of (full moon against the dark
sky) is characteristic. The main concern is
the surgical removal of the cyst and its
contents safely, without spilling the
scolices-rich fluid into the surgical field and
thus avoiding recurrence and surgical
closure of the bronchial fistulae to achieve
early and full lung expansion
postoperatively. Safe removal requires
protection of the airways from fluid spillage
and drowning during surgery. This is the
combined responsibility of the surgeon and
anaesthesiologist. No double-lumen
endotracheal tubes are designed for
children due to their small airways.

58. BILATERAL PULMONARY HYDATIDOSIS