Vascular Surgery
Lec: 4
Vascular Injuries:-
Etiology:-
1.Pentrating injuries: a- Low velocity injuries like knife, pistol in which
the damage is mainly confined to the wound tract.
b- High velocity injuries like missiles, gunshot which leads to soft tissue cavitation and
impact injury to the bone here the involved artery usually destroyed and/or
thrombosed for several Cms beyond the path of penetration.
2. Blunt trauma: a- Compressive force can damage arterial wall directly. b-
Rapid deceleration may stretch the artery and leads to intimal tear since it is the least
elastic layer of the arterial wall, blood will dissect under intimal flap leading to
thrombosis of vessel.
Pathophysiology:-
1. Complete cut of an artery here the cut ends will constrict
and retract into adjacent tissue, bleeding usually stop due to vasoconstriction and
development of firm thrombus in each of the two ends, clot tend to propagate
distally till the flow is restored by collateral circulation here distal blood flow will be
lost and ischemia develop whose severity vary according to a- the site of
interruption. b- the quality of collateral vessels c- the demand of distally
supplied tissue. Symtoms are usually found one major joint below the site of
arterial injury, the skin become cold, pale or mottled with numbness or sensory loss,
loss of movement, sometimes these findings may delay and loss of pulse is the only
finding, in some cases recurrent episodes of bleeding may occur and alarm prescence
of vascular injury.
2. Partly injuried artery in which part of arterial wall remain intact and complete
arterial contriction cannot occur as in case of total injury this will produce serious or
recurrent bleeding, large hematoma may develop and usually become pulsatile since
it communicate with arterial lumen, blood flow may be maintained distally and end-
organ ischemia is less found, it may escape diagnosis initially and later will present as
an expanding hematoma, false anuyrism or arteriovenous fistula.
3. Non Severed artery here intimal damage produce intra-arterial thrombosis and
arterial flow will be lost or decreased but without external bleeding, examination
may be normal initially, but signs of ischemia may develop over a variable period of
time.
Clinical evaluation:-
most arterial injuries can be identified readily because of
external bleeding or large hematomas, ischemia distal to the injury is uncommon
with isolated vascular injury except for wounds of popliteal and common femoral
arteries, moreover, distal arterial pulses may be intact in 20% of cases, the clinical
indications for emergency operative exploration of a suspected vascular wound are
summarized as following.
1.Diminished or absent distal pulse. 2.Persistant arterial bleeding.
3.Large or expanding hematoma. 4.Major bleeding with hypotension or shok.
5.Bruit at or distal to suspected site of injury. 6.injury of anatomically related nerve.
When they are available and the conditions are appropriate Dopplar study and
Angiography can be very helpful in the evaluation of potential arterial injuries
especially in multi-injured patient, moreover, surgical management may be improved
by identifying the site and extent of vascular damage.
Operative Mangement:-
all major arterial injuries should be repaired provided
that the tissue they supply is viable and the general condition of the patient is
satisfactory, the urgency of repair is directly related to the degree of ischemia,
although every hour delay may diminish success rate, there is no absolute period
beyond which repair is contraindicated, following steps must be done.
1. Ensure safe airways and breathing, control external bleeding with direct pressure
and packing of bleeding site, proximal torniqet is better to avoided, but if they are
necessary the time period of its application must be calculated, antibiotic and
tetanus prophylaxis are given, when present other injuries are evaluated and priority
determined
2. A wide operative field is prepared including the other limb in cases of lower limb
injury to allow Saphenous vein graft(SVG) harvesting when it is required, vertical
incisions along the course of injured vessel are used and proximal and distal control
of vessel obtained to decrease the amount of bleeding.
3. Both proximal and distal ends of injured vessel are dissected out, Embolectomy
using Fogarty catheter of both segments done to remove any present clots, irrigation
with Heparin/Saline solution done, both ends are trimed and continuity of the vessel
is re-established either by direct end to end anastamosis or when the lost segment is
large by reversed SVG interposition, hemostasis secured, wound debrided,
anastamosis must be covered with muscle or flap, drain put and incision closed.
4. post-operative care include maintenance of normal intravascular volume, distal
pulse evaluation by examination and/or dopplar study and moniter of distal limb to
avoid development of compartment syndrome.