Re-drainage
Many cases of chronic empyema will heal by
re-expansion of the lung if proper dependent drainage is provided. In those
instances in which there is a discharging sinus or a drainage tube in situ, 5
millilitres of iodized oil should be introduced into the cavity through the
sinus or tube, and skiagrams should be taken in the antero-posterior and
lateral positions. From these it is possible to decide the position which a
tube should occupy in order to provide dependent drainage. If a sinus leads into
the bottom of the empyema, it may be dilated by the introduction of a
laminaria tent, and a tube of adequate calibre subsequently fixed in position.
A sinus should never be dilated with bougies, for cases have been reported in
which this procedure has been followed by the formation of a brain abscess. If
the sinus or tube does not lead into the bottom of the cavity, dependent
drainage should be provided by the resection of a portion of rib; the site for
this operation may be determined from the skiagrams taken after the
introduction of iodized oil. Resection of a rib gives an opportunity to obtain
a biopsy of the cavity wall for examination for evidence of tuberculosis, and
also to inspect the interior of the cavity and thus exclude the presence of a
foreign body. Therefore, even in those cases in which there is already an
opening into the bottom of the cavity, resection of a portion of rib is usually
preferable to dilatation of the sinus with a laminaria tent. The drainage tube
is cut flush with the chest wall and allowed to discharge into the dressings,
because the mild negative pressure induced by water-seal drainage is
insufficient to influence re-expansion of the lung in a chronic case. It is possible to use much higher negative pressures
(5-20 centimetres of mercury) by means of a suction pump, and there are many
observers who believe that suction hastens obliteration of a chronic empyema.
However, although suction is theoretically sound, it is doubtful whether it is
of much practical value. In my own opinion, expansion of the lung is encouraged
more by vigorous physical exercise than by suction and, as it is impossible to
employ both simultaneously, physical activity should take priority. It is, of
course, possible to use suction at night and leave the patient free to exercise
himself during the day, and this may be a happy compromise for those who
believe that suction really does influence re-expansion of the lung. There is
no doubt, however, that re-expansion of the lung depends rather on breathing
exercises and physical activity than on any other factor.
Irrigation of a properly-drained chronic empyema
serves no purpose and therefore has no place in treatment.
After dependent drainage has been provided, progress
in re-expansion of the lung should be observed from sinograms (see page
34) taken at intervals of 2-4 weeks. When the cavity is small the sinograms may
be more informative if the cavity is filled with iodized oil and the films are
taken with the patient recumbent. The tube should not be permanently removed
until these sinograms show that the cavity has been obliterated.
In many cases of chronic empyema, dependent drainage
is followed by obliteration of the cavity, provided that the patient carries
out his post-operative treatment with enthusiasm. If the sinograms show that
the empyema has become static in size, the need for further operative treatment
must be accepted.
Decortication
The obvious ideal treatment of a chronic empyema is
operative removal of the fibrous tissue which covers the lung and chest wall,
so that the lung is free to expand and respiratory movement of the chest wall
is unhampered. This operation, known as decortication, is particularly suitable
for chronic undrained sterile empyemas, and also for persistent drained
cavities which are large, because, in the latter case, the alternative
operation of mobilization of the chest wall is certain to lead to considerable
diminution in respiratory function. A "large" empyema may be defined
here as one in which the cavity extends under more than 4 ribs.
Decortication is performed under general anaesthesia.
An intravenous infusion should be set up before starting the operation, because
decortication is often accompanied by considerable loss of blood, which should
be balanced by transfusion. Operative exposure is obtained by resecting a long
length of a rib overlying the centre of the cavity. The thick fibrous tissue
which lines the chest wall is separated from the parietes by blunt dissection ;
in old-standing cases, this may require the use of considerable force. The
separation is then continued over the surface of the lung, and this calls for
much care and patience in order to avoid serious damage to the lung. A certain
amount of trauma to the lung is often unavoidable and, consequently, blood and
air may leak from its surface at numerous points, but this is harmless provided
that the injury is superficial. The operation is not terminated until all the
fibrous tissue has been removed, including that on the surface of the
diaphragm. It is also advisable to free
the lung from adhesions for
some distance beyond the perimeter of the empyema ; ideally the whole lung
should be freed from attachment to the parietes. The decortication must not be
considered adequate until the anaesthetist is able, by the use of positive pressure,
to inflate the lung to such a degree that the pleural space is completely
obliterated. Before the chest is closed, a small intercostal tube is inserted
at the apex of the space and another of larger bore is introduced at the base.
Mechanical suction is
applied to the apical tube during the first 48 hours after operation ; this
tube is then removed. The basal tube is used for drainage into a water-seal
bottle and is taken "out after 3 or 4 days. Any fluid or air which
accumulates after this time should be removed immediately by aspiration.
Breathing exercises and early activity are important factors in gaining and
maintaining complete re-expansion of the lung and in restoring full
respiratory movement.
In
some cases decortication may prove technically impossible and have to be
abandoned ; drainage of the empyema must then be continued and the cavity
subsequently obliterated by a plastic operation on the chest wall.
When
decortication achieves its object, the result is extremely pleasing, for the
patient is left with no deformity or reduction in respiratory capacity (Fig.
17).
Plastic operations on the chest wall
With small
chronic empyemas—that is to say, those which do not extend under more
than 4 ribs—the cavity may be obliterated more simply by mobilizing the chest
wall than by decortication, and, since the mobilization is limited to a small
area, the subsequent deformity and loss of function is not serious. A plastic
operation on the chest wall is also indicated in the case of larger cavities
when decortication has proved impossible.
In all operations of
this type it is necessary to resect the ribs overlying the cavity and for a
short distance beyond it. If the cavity is large—that
is, in a case in which decortication has failed—this decostalization will
involve the removal of a large number of ribs, and it is then usually wise to
divide the procedure into 2 or more stages. When the ribs overlying the cavity
have been removed, the chest wall remains too rigid to fall into contact with
the underlying lung, because of the thick fibrous tissue which forms the
parietal wall of the empyema. This obstacle may be overcome either by excising
the parietal wall of the cavity, together with the overlying intercostal
tissues (Schede's operation), or by further mobilization of the parietal wall
so that it can be brought into contact with the visceral wall (Roberts' flap
operation). With Schede's operation, which is the most suitable procedure for
very small cavities, particularly if there is a fistula present, the cavity is
packed with dry gauze. The cavity is subsequently repacked daily, so that the
wound heals partly by the formation of granulation tissue and partly as a
result of the fact that the overlying soft tissues are gradually drawn into
contact with the visceral wall of the cavity, to which they adhere. In Roberts'
flap operation, the cavity is opened along its inferior, anterior and superior
boundaries, so that the parietal wall forms a flap hinged posteriorly. This
flap is rotated outwards and a wedge of fibrous tissue excised along the line
where the visceral and parietal walls meet posteriorly. The flap is thus sufficiently
(a)
(b)
(a) (b)
mobilized to allow it to fall on to the visceral wall
of the empyema. It is held in this position by a pack placed on its outer
surface. The skin and superficial muscles are sutured over this pack, leaving a
small opening for drainage. The pack is removed after 10 days and the wound
firmly strapped over a large pad of gauze and cotton wool. With moderate and
large-sized cavities this operation is preferable to Schede's operation,
because it is more likely to be successful, and there is less deformity as well
as a quicker convalescence.
hae mopneumo-thorax. (b) months
after decortication.
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