Alexis Thomson and Alexander Miles - Manual of Surgery

A >> Alexis Thomson and Alexander Miles >> Manual of Surgery

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A comparison of the pulse in the artery beyond the seat of the aneurysm
with that in the corresponding artery on the healthy side, shows that on
the affected side the wave is smaller in volume, and delayed in time. A
pulse tracing shows that the normal impulse and dicrotic waves are lost,
and that the force and rapidity of the tidal wave are diminished.

[Illustration: FIG. 71.--Radiogram of Aneurysm of Aorta, showing
laminated clot and erosion of bodies of vertebrae. The intervertebral
discs are intact.]

An aneurysm exerts pressure on the surrounding structures, which are
usually thickened and adherent to it and to one another. Adjacent veins
may be so compressed that congestion and oedema of the parts beyond are
produced. Pain, disturbances of sensation, and muscular paralyses may
result from pressure on nerves. Such bones as the sternum and vertebrae
undergo erosion and are absorbed by the gradually increasing pressure of
the aneurysm. Cartilage, on the other hand, being elastic, yields before
the pressure, so that the intervertebral discs or the costal cartilages
may escape while the adjacent bones are destroyed (Fig. 71). The skin
over the tumour becomes thinned and stretched, until finally a slough
forms, and when it separates haemorrhage takes place.

[Illustration: FIG. 72.--Sacculated Aneurysm of Abdominal Aorta nearly
filled with laminated clot. Note greater density of clot towards
periphery.]

In the progress of an aneurysm towards rupture, timely clotting may
avert death for the moment, but while extension in one direction has
been arrested there is apt to be extension in another, with imminence of
rupture, or it may be again postponed.

#Differential Diagnosis.#--The diagnosis is to be made from other
pulsatile swellings. Pulsation is sometimes transmitted from a large
artery to a tumour, a mass of enlarged lymph glands, or an inflammatory
swelling which lies in its vicinity, but the pulsation is not
expansile--a most important point in differential diagnosis. Such
swellings may, by appropriate manipulation, be moved from the artery and
the pulsation ceases, and compression of the artery on the cardiac side
of the swelling, although it arrests the pulsation, does not produce any
diminution in the size or tension of the swelling, and when the pressure
is removed the pulsation is restored immediately.

Fluid swellings overlying an artery, such as cysts, abscesses, or
enlarged bursae, may closely simulate aneurysm. An apparent expansion may
accompany the pulsation, but careful examination usually enables this to
be distinguished from the true expansion of an aneurysm. Compression of
the artery makes no difference in the size or tension of the swelling.

Vascular tumours, such as sarcoma and goitre, may yield an expansile
pulsation and a soft, whifling bruit, but they differ from an aneurysm
in that they are not diminished in size by compression of the main
artery, nor can they be emptied by pressure.

The exaggerated pulsation sometimes observed in the abdominal aorta, the
"pulsating aorta" seen in women, should not be mistaken for aneurysm.

#Prognosis.#--When _natural cure_ occurs it is usually brought about by
the formation of laminated clot, which gradually increases in amount
till it fills the sac. Sometimes a portion of the clot in the sac is
separated and becomes impacted as an embolus in the artery beyond,
leading to thrombosis which first occludes the artery and then extends
into the sac.

The progress of natural cure is indicated by the aneurysm becoming
smaller, firmer, less expansile, and less compressible; the murmur and
thrill diminish and the pressure effects become less marked. When the
cure is complete the expansile pulsation is lost, and there remains a
firm swelling attached to the vessel (_consolidated aneurysm_). While
these changes are taking place the collateral arteries become enlarged,
and an anastomotic circulation is established.

An aneurysm may prove _fatal_ by exerting pressure on important
structures, by causing syncope, by rupture, or from the occurrence of
suppuration. _Pressure_ symptoms are usually most serious from aneurysms
situated in the neck, thorax, or skull. Sudden fatal _syncope_ is not
infrequent in cases of aneurysm of the thoracic aorta.

_Rupture_ may take place through the skin, on a mucous or serous
surface, or into the cellular tissue. The first haemorrhage is often
slight and stops naturally, but it soon recurs, and is so profuse,
especially when the blood escapes externally, that it rapidly proves
fatal. When the bleeding takes place into the cellular tissue, the
aneurysm is said to become _diffused_, and the extravasated blood
spreads widely through the tissues, exerting great pressure on the
surrounding structures.

The _clinical features_ associated with rupture are sudden and severe
pain in the part, and the patient becomes pale, cold, and faint. If a
comparatively small escape of blood takes place into the tissues, the
sudden alteration in the size, shape, and tension of the aneurysm,
together with loss of pulsation, may be the only local signs. When the
bleeding is profuse, however, the parts beyond the aneurysm become
greatly swollen, livid, and cold, and the pulse beyond is completely
lost. The arrest of the blood supply may result in gangrene. Sometimes
the pressure of the extravasated blood causes the skin to slough and,
later, give way, and fatal haemorrhage results.

The _treatment_ is carried out on the same lines as for a ruptured
artery (p. 261), it being remembered, however, that the artery is
diseased and does not lend itself to reconstructive procedures.

_Suppuration_ may occur in the vicinity of an aneurysm, and the aneurysm
may burst into the abscess which forms, so that when the latter points
the pus is mixed with broken-down blood-clot, and finally free
haemorrhage takes place. It has more than once happened that a surgeon
has incised such an abscess without having recognised its association
with aneurysm, with tragic results.

#Treatment.#--In treating an aneurysm, the indications are to imitate
Nature's method of cure by means of laminated clot.

_Constitutional treatment_ consists in taking measures to reduce the
arterial tension and to diminish the force of the heart's action. The
patient must be kept in bed. A dry and non-stimulating diet is
indicated, the quantity being gradually reduced till it is just
sufficient to maintain nutrition. Saline purges are employed to reduce
the vascular tension. The benefit derived from potassium iodide
administered in full doses, as first recommended by George W. Balfour,
probably depends on its depressing action on the heart and its
therapeutic benefit in syphilis. Pain or restlessness may call for the
use of opiates, of which heroin is the most efficient.

_Local Treatment._--When constitutional treatment fails, local measures
must be adopted, and many methods are available.

#Endo-aneurysmorrhaphy.#--The operation devised by Rudolf Matas in 1888
aims at closing the opening between the sac and its feeding artery, and
in addition, folding the wall of the sac in such a way as to leave no
vacant space. If there is marked disease of the vessel, Matas' operation
is not possible and recourse is then had to ligation of the artery just
above the sac.

_Extirpation of the Sac--The Old Operation._--The procedure which goes
by this name consists in exposing the aneurysm, incising the sac,
clearing out the clots, and ligating the artery above and below the sac.
This method is suitable to sacculated aneurysm of the limbs, so long as
they are circumscribed and free from complications. It has been
successfully practised also in aneurysm of the subclavian, carotid, and
external iliac arteries. It is not applicable to cases in which there is
such a degree of atheroma as would interfere with the successful
ligation of the artery. The continuity of the artery may be restored by
grafting into the gap left after excision of the sac a segment of the
great saphena vein.

_Ligation of the Artery._--The object of tying the artery is to diminish
or to arrest the flow of blood through the aneurysm so that the blood
coagulates both in the sac and in the feeding artery. The ligature may
be applied on the cardiac side of the aneurysm--proximal ligation, or to
the artery beyond--distal ligation.

_Proximal Ligation._--The ligature may be applied immediately above the
sac (Anel, 1710) or at a distance above (John Hunter, 1785). The
_Hunterian operation_ ensures that the ligature is applied to a part of
the artery that is presumably healthy and where relations are
undisturbed by the proximity of the sac; the best example is the
ligation of the superficial femoral artery in Scarpa's triangle or in
Hunter's canal for popliteal aneurysm; it is on record that Syme
performed this operation with cure of the aneurysm on thirty-nine
occasions.

It is to be noted that the Hunterian ligature does not aim at
_arresting_ the flow of blood through the sac, but is designed so to
diminish its volume and force as to favour the deposition within the sac
of laminated clot. The development of the collateral circulation which
follows upon ligation of the artery at a distance above the sac may be
attended with just that amount of return stream which favours the
deposit of laminated clot, and consequently the cure of the aneurysm;
the return stream may, however, be so forcible as to prevent coagulation
of the blood in the sac, or only to allow of the formation of a red
thrombus which may in its turn be dispersed so that pulsation in the sac
recurs. This does not necessarily imply failure to cure, as the
recurrent pulsation may only be temporary; the formation of laminated
clot may ultimately take place and lead to consolidation of the
aneurysm.

The least desirable result of the Hunterian ligature is met with in
cases where, owing to widespread arterial disease, the collateral
circulation does not develop and gangrene of the limb supervenes.

_Anel's ligature_ is only practised as part of the operation which deals
with the sac directly.

_Distal Ligation._--The tying of the artery beyond the sac, or of its
two branches where it bifurcates (Brasdor, 1760, and Wardrop, 1825), may
arrest or only diminish the flow of blood through the sac. It is less
successful than the proximal ligature, and is therefore restricted to
aneurysms so situated as not to be amenable to other methods; for
example, in aneurysm of the common carotid near its origin, the artery
may be ligated near its bifurcation, or in aneurysm of the innominate
artery, the carotid and subclavian arteries are tied at the seat of
election.

_Compression._--Digital compression of the feeding artery has been given
up except as a preparation for operations on the sac with a view to
favouring the development of a collateral circulation.

_Macewen's acupuncture or "needling"_ consists in passing one or more
fine, highly tempered steel needles through the tissues overlying the
aneurysm, and through its outer wall. The needles are made to touch the
opposite wall of the sac, and the pulsation of the aneurysm imparts a
movement to them which causes them to scarify the inner surface of the
sac. White thrombus forms on the rough surface produced, and leads to
further coagulation. The needles may be left in position for some hours,
being shifted from time to time, the projecting ends being surrounded
with sterile gauze.

The _Moore-Corradi method_ consists in introducing through the wall of
the aneurysm a hollow insulated needle, through the lumen of which from
10 to 20 feet of highly drawn silver or other wire is passed into the
sac, where it coils up into an open meshwork (Fig. 73). The positive
pole of a galvanic battery is attached to the wire, and the negative
pole placed over the patient's back. A current, varying in strength from
20 to 70 milliamperes, is allowed to flow for about an hour. The hollow
needle is then withdrawn, but the wire is left _in situ_. The results
are somewhat similar to those obtained by needling, but the clot formed
on the large coil of wire is more extensive.

[Illustration: FIG. 73.--Radiogram of Innominate Aneurysm after
treatment by the Moore-Corradi method. Two feet of finely drawn silver
wire were introduced. The patient, a woman, aet. 47, lived for ten months
after operation, free from pain (cf. Fig. 75).]

Colt's method of wiring has been mainly used in the treatment of
abdominal aneurysm; gilt wire in the form of a wisp is introduced
through the cannula and expands into an umbrella shape.

_Subcutaneous Injections of Gelatin._--Three or four ounces of a 2 per
cent. solution of white gelatin in sterilised water, at a temperature of
about 100 F., are injected into the subcutaneous tissue of the abdomen
every two, three, or four days. In the course of a fortnight or three
weeks improvement may begin. The clot which forms is liable to soften
and be absorbed, but a repetition of the injection has in several cases
established a permanent cure.

_Amputation of the limb_ is indicated in cases complicated by
suppuration, by secondary haemorrhage after excision or ligation, or by
gangrene. Amputation at the shoulder was performed by Fergusson in a
case of subclavian aneurysm, as a means of arresting the blood-flow
through the sac.

TRAUMATIC ANEURYSM

The essential feature of a traumatic aneurysm is that it is produced by
some form of injury which divides all the coats of the artery. The walls
of the injured vessel are presumably healthy, but they form no part of
the sac of the aneurysm. The sac consists of the condensed and thickened
tissues around the artery.

The injury to the artery may be a subcutaneous one such as a tear by a
fragment of bone: much more commonly it is a punctured wound from a stab
or from a bullet.

The aneurysm usually forms soon after the injury is inflicted; the blood
slowly escapes into the surrounding tissues, gradually displacing and
condensing them, until they form a sac enclosing the effused blood.

Less frequently a traumatic aneurysm forms some considerable time after
the injury, from gradual stretching of the fibrous cicatrix by which the
wound in the wall of the artery has been closed. The gradual stretching
of this cicatrix results in condensation of the surrounding structures
which form the sac, on the inner aspect of which laminated clot is
deposited.

A traumatic aneurysm is almost always sacculated, and, so long as it
remains circumscribed, has the same characters as a pathological
sacculated aneurysm, with the addition that there is a scar in the
overlying skin. A traumatic aneurysm is liable to become diffuse--a
change which, although attended with considerable risk of gangrene, has
sometimes been the means of bringing about a cure.

The treatment is governed by the same principles as apply to the
pathological varieties, but as the walls of the artery are not diseased,
operative measures dealing with the sac and the adjacent segment of the
affected artery are to be preferred.

ARTERIO-VENOUS ANEURYSM

An abnormal communication between an artery and a vein constitutes an
arterio-venous aneurysm. Two varieties are recognised--one in which the
communication is direct--_aneurysmal varix_; the other in which the
vein communicates with the artery through the medium of a sac--_varicose
aneurysm_.

Either variety may result from pathological causes, but in the majority
of cases they are traumatic in origin, being due to such injuries as
stabs, punctured wounds, and gun-shot injuries which involve both artery
and vein. In former times the most common situation was at the bend of
the elbow, the brachial artery being accidentally punctured in
blood-letting from the median basilic vein. Arterio-venous aneurysm is a
frequent result of injuries by modern high-velocity bullets--for
example, in the neck or groin.

In _aneurysmal varix_ the higher blood pressure in the artery forces
arterial blood into the vein, which near the point of communication with
the artery tends to become dilated, and to form a thick-walled sac,
beyond which the vessel and its tributaries are distended and tortuous.
The clinical features resemble those associated with varicose veins, but
the entrance of arterial blood into the dilated veins causes them to
pulsate, and produces in them a vibratory thrill and a loud murmur. In
those at the groin, the distension of the veins may be so great that
they look like sinuses running through the muscles, a feature that must
be taken into account in any operation.

As the condition tends to remain stationary, the support of an elastic
bandage is all that is required; but when the condition progresses and
causes serious inconvenience, it may be necessary to cut down and expose
the communication between the artery and vein, and, after separating the
vessels, to close the opening in each by suture; this may be difficult
or impossible if the parts are matted from former suppuration. If it is
impossible thus to obliterate the communication, the artery should be
ligated above and below the point of communication; although the risk of
gangrene is considerable unless means are taken to develop the
collateral circulation beforehand (Makins).

_Varicose aneurysm_ usually develops in relation to a traumatic
aneurysm, the sac becoming adherent to an adjacent vein, and ultimately
opening into it. In this way a communication between the artery and the
vein is established, and the clinical features are those of a
combination of aneurysm and aneurysmal varix.

As there is little tendency to spontaneous cure, and as the aneurysm is
liable to increase in size and finally to rupture, operative treatment
is usually called for. This is carried out on the same lines as for
aneurysmal varix, and at the same time incising the sac, turning out the
clots, and ligating any branches which open into the sac. If it can be
avoided, the vein should not be ligated.

ANEURYSMS OF INDIVIDUAL ARTERIES

#Thoracic Aneurysm.#--All varieties of aneurysm occur in the aorta, the
fusiform being the most common, although a sacculated aneurysm
frequently springs from a fusiform dilatation.

The _clinical features_ depend chiefly on the direction in which the
aneurysm enlarges, and are not always well marked even when the sac is
of considerable size. They consist in a pulsatile swelling--sometimes in
the supra-sternal notch, but usually towards the right side of the
sternum--with an increased area of dulness on percussion. With the
X-rays a dark shadow is seen corresponding to the sac. Pain is usually a
prominent symptom, and is largely referable to the pressure of the
aneurysm on the vertebrae or the sternum, causing erosion of these bones.
Pressure on the thoracic veins and on the air-passage causes cyanosis
and dyspnoea. When the oesophagus is pressed upon, the patient may have
difficulty in swallowing. The left recurrent nerve may be stretched or
pressed upon as it hooks round the arch of the aorta, and hoarseness of
the voice and a characteristic "brassy" cough may result from paralysis
of the muscles of the larynx which it supplies. The vagus, the phrenic,
and the spinal nerves may also be pressed upon. When the aneurysm is on
the transverse part of the arch, the trachea is pulled down with each
beat of the heart--a clinical phenomena known as the "tracheal tug."
Aneurysm of the descending aorta may, after eroding the bodies of the
vertebrae (Fig. 71) and posterior portions of the ribs, form a swelling
in the back to the left of the spine.

Inasmuch as obliteration of the sac and the feeding artery is out of the
question, surgical treatment is confined to causing coagulation of the
blood in an extension or pouching of the sac, which, making its way
through the parietes of the chest, threatens to rupture externally. This
may be achieved by Macewen's needles or by the introduction of wire into
the sac. We have had cases under observation in which the treatment
referred to has been followed by such an amount of improvement that the
patient has been able to resume a laborious occupation for one or more
years. Christopher Heath found that improvement followed ligation of the
left common carotid in aneurysm of the transverse part of the aortic
arch.

[Illustration: FIG. 74.--Thoracic Aneurysm, threatening to rupture
externally, but prevented from doing so by Macewen's needling. The
needles were left in for forty-eight hours.]

#Abdominal Aneurysm.#--Aneurysm is much less frequent in the abdominal
than in the thoracic aorta. While any of the large branches in the
abdomen may be affected, the most common seats are in the aorta itself,
just above the origin of the coeliac artery and at the bifurcation.

The _clinical features_ vary with the site of the aneurysm and with its
rapidity and direction of growth. A smooth, rounded swelling, which
exhibits expansile pulsation, forms, usually towards the left of the
middle line. It may extend upwards under cover of the ribs, downwards
towards the pelvis, or backward towards the loin. On palpation a
systolic thrill may be detected, but the presence of a murmur is neither
constant nor characteristic. Pain is usually present; it may be
neuralgic in character, or may simulate renal colic. When the aneurysm
presses on the vertebrae and erodes them, the symptoms simulate those of
spinal caries, particularly if, as sometimes happens, symptoms of
compression paraplegia ensue. In its growth the swelling may press upon
and displace the adjacent viscera, and so interfere with their
functions.

The _diagnosis_ has to be made from solid or cystic tumours overlying
the artery; from a "pulsating aorta"; and from spinal caries; much help
is obtained by the use of the X-rays.

The condition usually proves fatal, either by the aneurysm bursting into
the peritoneal cavity, or by slow leakage into the retro-peritoneal
tissue.

The Moore-Corradi method has been successfully employed, access to the
sac having been obtained by opening the abdomen. Ligation of the aorta
has so far been unsuccessful, but in one case operated upon by Keen the
patient survived forty-eight days.

#Innominate aneurysm# may be of the fusiform or of the sacculated
variety, and is frequently associated with pouching of the aorta. It
usually grows upwards and laterally, projecting above the sternum and
right clavicle, which may be eroded or displaced (Fig. 75). Symptoms of
pressure on the structures in the neck, similar to those produced by
aortic aneurysm, occur. The pulses in the right upper extremity and in
the right carotid and its branches are diminished and delayed. Pressure
on the right brachial plexus causes shooting pain down the arm and
muscular paresis on that side. Vaso-motor disturbances and contraction
of the pupil on the right side may result from pressure on the
sympathetic. Death may take place from rupture, or from pressure on the
air-passage.

[Illustration: FIG. 75.--Innominate Aneurysm in a woman, aet. 47, eight
months after treatment by Moore-Corradi method (cf. Fig. 73).]

The available methods of treatment are ligation of the right common
carotid and third part of the right subclavian (Wardrop's operation), of
which a number of successful cases have been recorded. Those most
suitable for ligation are cases in which the aneurysm is circumscribed
and globular (Sheen). If ligation is found to be impracticable, the
Moore-Corradi method or Macewen's needling may be tried.

#Carotid Aneurysms.#--Aneurysm of the _common carotid_ is more frequent
on the right than on the left side, and is usually situated either at
the root of the neck or near the bifurcation. It is the aneurysm most
frequently met with in women. From its position the swelling is liable
to press on the vagus, recurrent and sympathetic nerves, on the
air-passage, and on the oesophagus, giving rise to symptoms referable to
such pressure. There may be cerebral symptoms from interference with the
blood supply of the brain.

Aneurysm near the origin has to be diagnosed from subclavian,
innominate, and aortic aneurysm, and from other swellings--solid or
fluid--met with in the neck. It is often difficult to determine with
precision the trunk from which an aneurysm at the root of the neck
originates, and not infrequently more than one vessel shares in the
dilatation. A careful consideration of the position in which the
swelling first appeared, of the direction in which it has progressed, of
its pressure effects, and of the condition of the pulses beyond, may
help in distinguishing between aortic, innominate, carotid, and
subclavian aneurysms. Skiagraphy is also of assistance in recognising
the vessel involved.

Tumours of the thyreoid, enlarged lymph glands, and fatty and
sarcomatous tumours can usually be distinguished from aneurysm by the
history of the swelling and by physical examination. Cystic tumours and
abscesses in the neck are sometimes more difficult to differentiate on
account of the apparently expansile character of the pulsation
transmitted to them. The fact that compression of the vessel does not
affect the size and tension of these fluid swellings is useful in
distinguishing them from aneurysm.