Victor A.Tarasov, Yuriy K.Sharov, Pyotr I.Azarov, Evgeny S.Pobegalov, Vladimir V.Stavrovietskiy, Igor V.L'vov, Igor A.Kondrashov, Konstantin P.Zhidkov, Mikhail B.Blium, Armen G.Andreassian
MATERIAL AND METHODS. 603 patients aged 6 - 82 with mediastinal masses
underwent major surgery. 408 masses were benign or noninvasive, 195 - malignant
or invasive; 134 of the latter invaded 1 - 9 adjacent organs and structures. 49
patients had 82 great vessels invaded. 40 patients demonstrated signs of
mediastinal compression. 550 radical, extended or combined operations, 36
decompressive ones, and 17 explorative ones were performed. RESULTS.
Postoperative morbidity made up 7.0%, mortality - 3.0%, both being the lowest
after simple and extended radical or decompressive surgery, and the highest -
after explorations. CONCLUSIONS. Surgery is indicated in all mediastinal masses
due to potential risk of mediastinal compression. In cases of advanced
complicated tumours, decompressive surgery is the most safe option, exploration
being the most dangerous. Replacement of invaded great veins with
polytetrafluorethylene grafts should become a routine stage of radical and
decompressive surgery of advanced invasive mediastinal neoplasms. Major surgery
of mediastinal lymphomas has a number of benefits and may be performed without
mortality and with minimal morbidity when detecting surgical extent accurately
and carefully. Bilateral resection of invaded phrenic nerves does not lead to
fatal respiratory failure and may be performed if needed.
BACKGROUND. Surgical
tactics in mediastinal neoplasms is defined by risks of their malignization,
invasion and compression of vitally important organs. Removal of mediastinal
cysts and non-invasive tumours usually doesn't present serious problems,
provided that choice of surgical approach is adequate. Yet, invasion of vitally
important organs significantly limits the possibility of radical surgery.
Another problem is mediastinal compression which might be caused by both
malignant and benign masses. Superior vena cava and/or brachiocephalic veins are
frequently affected: mediastinal masses are now considered to be the most
common reason of superior vena cava syndrome (1). Major airway compression by
mediastinal neoplasms produces severe respiratory insufficiency which, in a
number of cases, can't be successfully managed by artificial ventilation. As
for mediastinal lymphomas, therapeutic approach seems to be rather
contradictory: on one hand, lymphomas are system diseases, and major surgery is
generally considered not to be appropriate for their treatment; on another
hand, extent of some mediastinal lymphomas and severity of produced symptoms
lead a number of authors to major surgical excisions, which, in their opinion,
not only provide rapid improvement of patients' condition, but also facilitate
consecutive specific therapy. With all disputability of this problem, the
surgeon's part in treatment of these patients seems to lack accurate
estimation.
MATERIAL AND METHODS. 603 patients with mediastinal
tumours and cysts underwent major surgery in our clinic from 1959 to 1998. 192
(31.8%) were male, 411 (68.2%) - female, age varying from 6 to 82 years; there
were 29 (4.8%) children and adolescents, 210 (38.4%) adults aged 18-40, and 364
(60.4%) were older than 40. 40 (6.6%) patients presented signs of mediastinal
compression: thoracic outlet syndrome in 2, superior vena cava syndrome in 30,
marked airway compression in 12, and other signs - in 2. 64.5% patients with
thymic masses presented generalized myasthenic syndrome, being of severe grade
in more than a half cases. Origination of
mediastinal masses is presented in Table 1.
Diagnostic
algorythm included 3-plan chest X-ray, multiplan chest roentgenoscopy,
pneumomediastinography, and pneumomediastinotomography; since 1990, the last
two methods were completely replaced by computed tomography and magnetic
resonance imaging.
Anaesthesia
in all cases was endotracheal narcosis. Surgical access was usually chosen
depending on mass localization. Retrosternal (mediastino-cervical) goiter was
successfully removed through standard cervical approach in the majority (89.1%)
of cases. Parasternal lipomas were removed as a rule through transrectal
approach with dilatation of Larrey's fissura. Overall, 262 (43.4%) median
sternotomies, 181 (30.0%) thoracotomy, 89 (14.8%) cervical, and 71 (11.8%)
other approaches were used.
408
(67.7%) masses appeared to be benign or noninvasive, 195 (32.3%) - malignant or
invasive. Invasion of 1 - 9 adjacent organs and structures was detected in 134
(22.2%) cases; in 49 of them, overall of 82 great vessels (66 veins, and 16
arteries) was revealed.
In 550
cases, radical surgery was performed, including 120 (19.9%) extended and 45
(7.5%) combined thymectomies, 47 (7.8%) other combined procedure, and 338
(56.0%) radical removal of masses without resection of adjacent organs and
structures. 36 (6.0%) patients underwent surgical mediastinal decompression
(excision of the most part of a tumour preserving some invaded adjacent
organs), and in 17 (2.8%) only exploration and biopsy was performed. In 3
patients, combined surgery included bilateral phrenic nerve resections.
In 19
(38.8%) of 49 patients with great vessel invasion, overall of 6 superior venae
cavae and 17 brachiocephalic veins were resected during combined procedures. In
6 of them, resected veins were reconstructed with polytetrafluorethylene grafts
(in one case, brachiocephalic vein was replaced with transposed azygos vein).
24 (49.0) patients underwent decompressive surgery, and 6 (12.2%) - only exploration.
14 (35.0%)
of 40 patients with signs of mediastinal compression underwent radical surgery,
21 (52.5%) - decompressive one, and 5 (12.5%) - exploration.
RESULTS. There were 42 (7.0%) postoperative complications; postoperative
mortality made up 3.0% (18 patients). Morbidity and mortality after different
kinds of surgery is presented in Table 2. There were no
thromboembolic complications after prosthetic replacement of great veins.
Overall,
the highest morbidity and mortality rate was seen after explorative surgery,
the lowest - after radical removal of benign masses and malignant tumours
without invasion of adjacent structures. In patients with invasion of adjacent
structures, mortality and morbidity were slightly above median rates. Morbidity
and mortality rates after combined surgery were comparatively higher than after
decompression. The same correlations are present in the groups of patients with
great vessel invasion and with mediastinal compression: morbidity and mortality
are the highest after explorative surgery, being the lowest after decompressive
one. Morbidity in cases with blood vessel prosthetic reconstruction was
slightly higher than in vessel resections without reconstruction, mortality in
these groups being similar.
Among 63
patients operated for mediastinal lymphoproliferative diseases, overall
mortality and morbidity rates exceed median ones; yet, there was no mortality
and minimal morbidity after simple and extended radical surgery and after
decompression. Morbidity and mortality rate after explorative and combined
surgery in lymphomas appeared to be comparatively high.
3 patients
who survived bilateral phrenic nerve resection experienced transitory
respiratory insufficiency which demanded artificial lung ventilation for 12
days postoperatively in 1 of them, but there was no mortality.
There were
no cases of thrombosis of blood vessel grafts 3 - 18 months after great vein
reconstruction.
DISCUSSION. According to our experience presented above, the worst
option in mediastinal tumours invading adjacent organs and structures
(especially great vessels) and/or complicated with mediastinal compression
seems to be explorative surgery. At the same time, surgical decompression is
possible in these cases with minimum of risk. So, we believe that, once the
chest is opened in a case of mediastinal tumour, it should not be closed
without at least prominent mediastinal decompression, if radical removal can't
be performed.
We are
fully agreed with those authors who consider that the use of prosthetic great
vessel replacement in their tumourous occlusion is warranted by immediate and
complete elimination of venous block and associated symptoms, which brings
quick and marked relief of patients' condition, even if radical surgery can't
be performed (2). In respect of comparatively low mortality and morbidity risk,
we suppose that prosthetic replacement of invaded great mediastinal veins
should be a routine stage of radical and decompressive surgical procedures in
invasive mediastinal neoplasms.
Severe
airway compression by mediastinal masses complicated by respiratory failure
presents an extremely dramatic situation and a number of difficult strategic
questions. Tracheobronchial stenting which pretends to become a standard
procedure for these patients (3, 4) is reported to be accompanied by mortality
rate up to 7% (4). As we have mentioned above
(see Table 2), decompressive surgery may
be performed in these cases with less mortality, to say nothing of benefits of
total or subtotal tumour removal - intoxication decrease, facilitation of
chemo- and radiotherapy, and some others.
Despite
general sceptical attitude to surgical removal of mediastinal lymphomas, our
results present us some reasons to agree with few advocates of surgery for
these patients. In our opinion, this kind of surgery may well be performed
without mortality and with minimal morbidity provided the choice of surgical
extent is accurate and careful. Benefits of removal of mediastinal lymphomas
are not only immediate mediastinal decompression, prevention of respiratory and
thromboembolic complications, facilitation of consecutive specific chemo- and
radiotherapy, but also providing plenty of pathological material for all kinds
of examinations and investigations, which, in a certain number of cases, may be
significant for accurate diagnosis. Importance of defining the role of surgery
in treatment of lymphomas is underlined by reports regarding low sensitivity of
a number of patients to chemotherapy (5, 6) and associated risks of great vein
thrombosis and pulmonary embolism (7).
At the
best of our knowledge, there are no reports of survival after bilateral phrenic
nerve resection. We suppose that 3 our patients who did survive had bilateral
phrenic nerve conductivity severely impaired for some time prior to surgery,
due to nerve invasion, so that they were adapted to respiration by means of
accessory respiratory musculature alone.
CONCLUSIONS. Significant number of mediastinal neoplasms are malignant
or invasive. Mediastinal masses always bear potential risk of mediastinal
compression; thus, surgery is indicated in all. In cases of invasion of
adjacent organs and structures, especially great vessels, and in mediastinal
compression, decompressive surgery is the most safe option, simple exploration
being the most dangerous. Indications and counter-indications for combined
radical surgery in advanced mediastinal tumours need further investigations and
adjustment. Replacement of invaded great veins with polytetrafluorethylene
grafts immediately relieves the symptoms of venous block, is not accompanied by
specific complications, and should become a routine stage of radical and
decompressive surgery of advanced invasive mediastinal neoplasms. Major surgery
of mediastinal lymphomas has a number of benefits and may be performed without
mortality and with minimal morbidity when detecting surgical extent accurately
and carefully. Bilateral resection of invaded phrenic nerves does not lead to
fatal respiratory failure and may be performed if needed.
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TABLE 1.
Origination of mediastinal masses.
Type of mediastinal
mass |
Number of cases |
% |
Thymomas |
154 |
25.5 |
Germ cell tumours |
15 |
2.5 |
Cysts |
94 |
15.6 |
Neurogenic tumours |
28 |
4.6 |
Lymphoproliferative diseases |
63 |
10.4 |
Lipomas |
87 |
14.4 |
Thyroid gland diseases |
106 |
17.6 |
Others |
56 |
9.3 |
TOTAL |
603 |
100.0 |
TABLE 2. Morbidity and mortality after different kinds of surgery.
Kind of surgery |
Patients |
%% |
Morbidity |
%% |
Mortality |
%% |
Total |
603 |
|
42 |
7.0 |
18 |
3.0 |
Simple and extended
radical |
458 |
76.0 |
19 |
4.1 |
3 |
0.7 |
Combined |
92 |
15.2 |
15 |
16.3 |
9 |
9.8 |
Decompressive |
36 |
6.0 |
3 |
8.3 |
2 |
5.6 |
Explorative |
17 |
2.8 |
5 |
29.4 |
4 |
23.5 |
|
|
|
|
|
|
|
Invasion of adjacent structures |
134 |
22.2 |
21 |
15.7 |
13 |
9.7 |
Combined |
92 |
68.7 |
16 |
17.4 |
9 |
9.8 |
Decompressive |
31 |
23.1 |
2 |
6.5 |
1 |
3.2 |
Explorative |
11 |
8.2 |
3 |
27.3 |
3 |
27.3 |
|
|
|
|
|
|
|
Invasion of great vessels |
49 |
8.1 |
12 |
24.5 |
8 |
16.3 |
With graft replacement |
6 |
12.2 |
2 |
33.3 |
1 |
16.7 |
Without graft replacement |
13 |
26.5 |
3 |
23.1 |
2 |
15.4 |
Decompressive |
24 |
49.0 |
4 |
16.7 |
2 |
8.3 |
Explorative |
6 |
12.2 |
3 |
50.0 |
3 |
50.0 |
|
|
|
|
|
|
|
Mediastinal compression |
40 |
6.6 |
6 |
15.0 |
5 |
12.5 |
Simple and extended
radical |
5 |
12.5 |
0 |
0.0 |
0 |
0.0 |
Combined |
9 |
22.5 |
3 |
33.3 |
2 |
22.2 |
Decompressive |
21 |
52.5 |
1 |
4.8 |
1 |
4.8 |
Explorative |
5 |
12.5 |
2 |
40.0 |
2 |
40.0 |
|
|
|
|
|
|
|
Mediastinal lymphomas |
63 |
10.4 |
5 |
7.9 |
4 |
6.3 |
Simple and extended
radical |
18 |
28.6 |
1 |
5.6 |
0 |
0.0 |
Combined |
24 |
38.1 |
3 |
12.5 |
3 |
12.5 |
Decompressive |
13 |
20.6 |
0 |
0.0 |
0 |
0.0 |
Explorative |
8 |
12.7 |
1 |
12.5 |
1 |
12.5 |
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