Vascular Trauma
Introduction
Trauma, both blunt and penetrating, is extremely common in Africa. As a result,
trauma to major vessels, in particular arteries, is a not uncommon clinical
occurrence. Some of the pathologic consequences of arterial injury including
bleeding and occlusion with tissue ischemia, are acute events demanding immediate
intervention to save life and limb and precluding any attempt at transfer or
referral. Therefore, the particular specialized surgical skills, techniques
and materials for the care of these patients need to be at the disposal of the
non-specialist African general surgeon. It is the purpose of this Review to
discuss these questions. While it will focus on the treatment of injured arteries,
attention will be given to those venous injuries which require surgical repair
rather than simple ligation. Finally photographs from the author’s personal
experience are presented in “Clinical cases”.
Epidemiology
The literature is full of epidemiological studies describing the features of
vascular trauma in various countries (1 - 9).
There is wide variation in the incidence, cause and mechanism of injury depending
on the local conditions. In a civilian population in Australia (5;9)
vascular injuries represent 1-2% of total trauma patients. However they account
for 20% of all trauma related death (5). Deaths from vascular
injury vary considerably with anatomic location and mechanism of injury. Thoracic
and abdominal injuries routinely have death rates between 30-50%; vascular injuries
to extremities are significantly lower in the range of 5%.
In an unparalleled large study from Vietnam Rich (10) reported
a total death of only 1.7% for all vascular injuries. It may be that life-threatening
vascular injuries were pre-selected by their failure to survive transport. In
the current warfare conditions of the American intervention in Iraq and Afghanistan
(11) vascular trauma represents 7% of total battle injuries,
88% of these were extremity injuries. The amputation rate was only 8% after
vascular repair.
In North India (3), with a low risk of personal violence, blunt
injuries, mostly motor vehicle accidents, account for 84% of vascular injuries.
Whereas in Medellin, Columbia (6) 93% of vascular injuries
are penetrating and in Georgia (2) they represent 85% of the
total. Surprisingly, in the European experience (8), up to
40% of vascular injuries are iatrogenic, as a result of vascular and other surgical
interventions. Kuwait (1) strikes a middle ground with 41%
penetrating, 23% a result of road traffic accidents (RTA) and 22% iatrogenic.
In Malaysia (4), over 50% of vascular injuries occur as a result
of RTAs.
As far as anatomic site of injury is concerned, variability is less. In Australia
(5;9) injuries are split almost equally between
thorax, abdomen and upper and lower extremities, with cervical injuries being
less common. In Latin America (7), extremity injuries are twice
as common as thoracic and abdominal, although these later result in a higher
mortality. As far as extremities are concerned upper and lower injuries occur
with similar frequency and the brachial, femoral and popliteal arteries are
the most commonly injured vessels. With special relevance to conditions in Africa,
in the Latin American survey (7), 68% of cases could be managed
on a clinical basis alone, that is without arteriography, and 78% were managed
within 6 hours of injury.
Pathology:
Basically, injury to an artery can result in rupture, occlusion or both. Rupture
leads to bleeding, either internal or external, depending on the circumstances,
or in cases of contained bleeding the more chronic condition of a traumatic
or false aneurysm. The other less common consequence of rupture occurs when
artery and parallel vein are each breached with a resulting arterio-venous fistula,
whose classical physical finding is the machine bruit. This condition, if sufficiently
large, can result in high output heart failure (12). Partial
rupture may or may not be associated with distal ischemia. Occlusion, whether
intrinsic, as in a contusion with intimal flap and dissection or after complete
transection, or extrinsic as a result of fracture and compression, results in
ischemia of the tissues reliant on the vascular supply. The degree of ischemia
is dependent on the associated collateral vessels and can be expressed in the
amputation rate when the specific vascular injury is treated by ligation: axillary
and brachial artery - 45-60%; common femoral artery – 80%; superficial
femoral – 45%; popliteal – 85% (13). Clearly successful
revascularization in these cases will reduce morbidity significantly. Thrombosis
and embolism are additional associated occlusive mechanisms.
The compartment syndrome (14) is an important complication
which may occur after reperfusion of previously ischemic extremities. It is
also associated with fractures, soft tissue injuries, burns and crush injuries
or, uncommonly, even after prolonged positioning (15). It
evolves as increasing pressure in an enclosed fascial compartment in either
the leg or forearm, which may surpass arterial pressure and result in further
ischemia, muscle necrosis and neurologic injury. Excessive pain and paresthesia
are the hallmarks of the complication and a high index of suspicion is required
to detect the problem. Intra-compartment pressures can be measured but in general
the rule is that fasciotomy should be carried out if the syndrome is suspected
or anticipated.
Trauma Mechanisms -
Blunt and penetrating trauma each has its associated pathological correlates.
Diagnosis of blunt injury is more often delayed. High impact frontal motor vehicle
collisions are associated with thoracic aortic injury, which will be discussed
below. Injury to abdominal aorta, iliac and femoral vessels may all occur with
blunt injury of sufficient force (16). Injury to the femoral
artery secondary to bicycle handlebars (17) is a condition
of which African surgeons should be aware. Vascular injury as a result of blunt
trauma to the extremities (18) is usually associated with
fractures although posterior dislocation of the knee is a well recognized cause.
Again even in the west 2/3 of these cases can be diagnosed on clinical basis
alone. Pediatric vascular injury has its own characteristics (19;20).
The morbidity and mortality of penetrating vascular injury is dependent on the
velocity and energy content of the trauma (21;22).
External bleeding is more common and the vascular injury usually diagnosed earlier.
All cases of penetrating trauma and significant bleeding near major arteries
should be explored with the suspicion of arterial injury and with preparation
for its repair as part of wound debridement (see below) even in the absence
of signs of distal ischemia. This will lower the risk of subsequent false aneurysm
or fistula.
Many scoring systems have been developed in order to standardize the assessment
of the severity of injury. (23;24)
Clinical Consequences
– Diagnosis of arterial injury starts with a suspicion based on the recognized
anatomy and mechanism of injury. The five “p”s are the classic clinical
signs of ischemia: pain, pallor (in white skinned individuals), paresthesia,
paralysis and pulselessness. Anyone having these signs has limb threatening
ischemia which mandates re-establishment of blood supply within 6 hours to prevent
irreversible tissue death. However lesser degrees of ischemia associated with
absence of the distal pulse can be tolerated if collateral flow is good. Trauma
surgeons have divided the clinical presentation of vascular trauma into hard
and soft signs. Hard signs include arterial bleeding, expanding or pulsatile
hematoma, bruit, pulse deficit or distal ischemia. Any one of these is a fairly
reliable sign of vascular trauma (25). Soft signs include
unexplained shock, history of significant bleeding, small hematoma, adjacent
nerve injury and proximity to major vessel and are less indicative of vascular
injury.
If you are lucky enough to have a hand held Doppler you can measure the blood
pressure at the ankle. An ankle/brachial pressure ratio (ABI) of <1 is abnormal
and denotes arterial injury in the absence of pre-existing occlusive disease.
Techniques:
The in hospital care of the trauma victim begins with initial assessment and
resuscitation according to the ABC Principles. These do not vary for those with
vascular injury except for an increased risk of requiring urgent operative intervention
to control bleeding.
Exposure - Standard exposures for major
arteries are well defined and should be adapted in cases of wounds to maintain
good soft tissue coverage (26). Specific descriptions of these
can be found in the relevant articles in the sections below (27-29).
Surgical Techniques – Specific surgical
techniques (30) must be mastered if successful vascular repair
is to be achieved. These include: proximal and distal exposure for control with
vascular clamps and loops; dissection and isolation of injured vessels including
veins; heparinization: local and/or systemic; use of vascular sutures; magnification
loops; assessment of injury: debridement, contusion, intimal flap and distal
dissection and thombosis; selective use of shunting; anatomic repairs:with vein
patch, end/end anastomosis without tension and reversed autologous vein graft
for larger defects; technical details of spatulated ends, running versus interrupted
sutures; distal thrombectomy (31); completion arteriography
(32); fasciotomy and soft tissue coverage. Proper handling
of the autogenous vein graft is important (33).
Fracture Management – The timing of
the vascular repair in relation to fracture management has long been a source
of controversy. The standard recommendation is for vascular repair to precede
orthopaedic management. Prevention of prolonged tissue ischemia is the objective.
While no prospective studies exist, McHenry (34), in a retrospective
study, suggested an increased need for fasciotomy when fractures are stabilized
before revascularization. No cases of disruption of vascular repair occurred
in 22 cases of subsequent fracture stabilization. Most fractures can be adequately
stabilized with traction or posterior plaster splinting but external fixation
may be necessary in some cases. Volgas (35) gives a good review
of management of ballistic injury.
Ancillary Measures – While the standard
techniques have been discussed above, certain other approaches can be mentioned.
Heroic extra-anatomic bypasses (36) can be carried out either
primarily in conditions of major tissue loss or presence of infection or secondarily
after initial failure. Endovascular techniques are being used increasingly in
hospitals with advanced vascular capability (37-39).
These are unlikely to be at the disposal of most African surgeons. Cardio-pulmonary
bypass may be of value in selected patients in settings where it is available
(40).
Imaging:
Imaging, in particular contrast arteriography, has played an important role
in the development of vascular surgery. While it is clear that advanced imaging
techniques are important in the management of zones 1 and 3 neck injuries (41)
and thoracic aortic disruption (42), for most extremity vascular
injuries pre-operative arteriography is not necessary. However on table operative
angiograms are easily carried out with a minimum of equipment and give important
information about the extent of injury and the adequacy of repair (32).
In suspected vascular injury exclusion arteriography has been shown to be cost-effective
(43).
Clinical and anatomic problems:
Cervical Vascular Injuries – Penetrating
injuries to the neck have been divided into three zones (28).
Suspected vascular injury in zones 1 & 3 in the presence of hard signs of
intra-cranial dysfunction mandates arteriography prior to exploration (41;44).
The operative approach is more difficult and the mortality higher with these
problems. Zone 2 injuries are recommended to undergo prompt exploration. Study
of the neurologic outcomes in neck injuries (45) shows that
the risk of cerebral infarction is unpredictable but that repair of injured
vessels gives a more favourable outcome than ligation.
Thoracic Vessels – Blunt thoracic aortic
injury is a specific clinical syndrome related to high impact deceleration injuries
and, although treatable, causes significant mortality related partially to delayed
diagnosis (27). Although 50% of victims die on impact, in
the rest the bleeding is temporarily contained by the aortic adventitia and
pleura and these patients are potentially salvageable. The injury typically
occurs at the site of the ligamentum arteriosum, just distal to the take off
of the left subclavian artery. The classic sign of widened mediastinum is unreliable
and investigation should be carried out in cases where there is a high index
of suspicion (42;46). Controversy remains
whether arch arteriography or CT scanning is more efficient in the diagnosis.
It appears that the use of heparin-bonded shunts allows improved results with
a lower incidence of paraplegia. Endovascular techniques are playing an expanding
role in the treatment of this problem (47).
Massive hemothorax requiring thoracotomy is defined as >1-1.5L at the time
of insertion of chest drains or 200-300ml/hr for the subsequent 4 hours. Some
of these cases will involve injury to the pulmonary vessels (48).
Abdominal Aorta and Visceral Vessels- Injuries
to major abdominal vessels are usually penetrating and cause significant mortality
often exceeding 50% (27;49;50).
Rapid decision-making is important in preventing exsanguination. Excessive attempts
at stabilization prior to laparotomy are unrewarding and fluid should actually
be restricted before surgical intervention (51). Severe refractory
hypotension or cardiac arrest prior to control of the abdominal aorta suggests
the need for initial thoracotomy and aortic clamping with cardiopulmonary massage
to stabilize the patient before exploration of the abdomen. A significant percentage
of cases have injuries to more that one major vessel. Visceral artery injuries
are particularly deadly (52). Survival rates are improved
with isolated venous and iliac injuries (51).
Upper Extremity - Injuries to the upper extremity
vessels are common, usually penetrating and may be associated with significant
nerve and orthopaedic injury (53). Blunt injury is usually
a result of supracondylar fracture of the humerus or dislocation of the elbow.
The amputation rate for ligation of the common brachial vessel is 55%; below
the take-off of the profunda brachial it is 25%. With isolated injury to the
infra-brachial vessels the amputation rate is even lower and ligation of either
the radial or ulnar arteries alone is usually well tolerated. A higher level
of technical skill is required in dealing with smaller vessels and use of magnification
loops has much to recommend it. Spasm of the vessels is more frequent and may
require topical lidocaine or intra-arterial papaverine. Prosthetic material
is not recommended. Passing of Fogarty catheters distally is important to remove
distal thrombus. Completion angiograms are important to detect abnormalities,
which might result in post-operative thrombosis of the repair. Soft tissue coverage
of the repair uses adjacent muscle. Fasciotomy needs to be done if ischemic
time is prolonged and orthopaedic stabilization should occur after vascular
repair. I would agree with Shanmugan (54) that pre-operative
angiography is seldom necessary, but cannot advocate all aspects of their management.
Lower Extremity: Hafez (55)
describes a large series of patients from South Africa with lower extremity
vascular injury. Only 19% of cases were a result of blunt trauma, the rest penetrating.
Only patients with “soft” signs of arterial injury had pre-operative
angiography, the rest were taken to the operating room for exploration. Surgically
the use of shunts was not routine, local heparinization only was used, fogarty
catheters were routinely passed and completion angiograms obtained, simple venous
injuries were repaired, complex ligated. If grafting was required contralateral
reversed saphenous vein was used. Revascularization was carried out before fracture
stabilization. In 46% of cases fasciotomies were performed; when there were
tense compartments, combined arterial and venous lesions, in the presence of
motor or sensory defect or in limbs of questionable viability. In the latter
case, if the superficial posterior and one other compartment showed non-viability,
a primary amputation was carried out. The amputation rate was 16%. I consider
this series to include all the important surgical features and recommend it
for further reading.
Femoral – Carillo (25) provides an
excellent review of femoral vascular injuries and describes the Mangled Extremity
Severity Scale (MESS) and its correlation with need for eventual amputation.
He also discusses the treatment of false aneurysm and arterio-venous fistula
in this area.
Popliteal/Infra-popliteal – Frykberg (56)
gives an excellent in-depth review of popliteal artery injuries and their management.
Blunt injuries carry almost 3 times the risk of amputation in comparison to
penetrating injuries. He points out that, in blunt trauma or major complex injury
of the lower leg, hard signs of vascular injury may be present as a result of
soft tissue or bony injury themselves. He recommends peri-operative hand injection
femoral arteriography for diagnosis. This does not mean delaying surgical management
by formal arteriography. In the presence of soft signs, non-operative management
on a clinical basis appears to yield as good results as arteriography and aggressive
vascular repair for minimal lesions. Posterior knee dislocations in the absence
of hard signs also can be managed without vascular exploration or arteriography.
Frykberg reviews the details of surgical management. Prepping the contralateral
leg for possible harvesting of the long saphenous vein should be remembered.
Injuries requiring resection of more than 2 cm are not amenable to primary anastomosis.
Popliteal vein injuries, which usually occur together with arterial ones, should
be repaired if possible. In the case of combined injuries intra-arterial shunts
may play a particular role. Prophylactic 4 quadrant fasciotomy done often as
the initial procedure is recommended in delayed injuries or those with complex
soft tissue damage. Woolgar (57) presents an experience with
the delayed presentation of popliteal artery pseudo-aneurysms.
Rowe (58) presents a review of infra-popliteal artery injuries.
The presence of 3 arteries in the leg, 2 of which the anterior and posterior
tibial arteries continue into the foot, provides a margin of safety when one
or even two is occluded. I should point out that the revascularization of infra-popliteal
vessels requires advanced vascular techniques. In the usual case of major soft
tissue trauma the decision is often one of primary amputation versus repair.
The absolute indications for primary amputation in these cases are: more than
6 hours of ischemic time and disruption of the posterior tibial nerve. The relative
indications are: severe foot wounds, poly-trauma, injuries requiring extensive
soft tissue coverage and tibial reconstruction. The details of repair are provided.
Complications:
Rich (10) reviews the complications, which may occur after
vascular repair. These are considerable and may occur in up to 30% of cases.
The major acute complications are thrombosis, infection and stenosis. Completion
angiography, the use of only autologous material for repair and adequate soft
tissue coverage are the means to decrease these risks. Delayed complications
are discussed as well.
Summary
Despite the specialized skills required, I believe repair of vascular injuries
primarily extremity injuries is not beyond the capacity of the district African
surgeon. This is also the position of COSECSA, which lists arterial repairs
in the FCS syllabus. The articles presented here provide the theoretical basis
for acquiring these skills. The traumatized population will provide the clinical
basis.
A vascular surgery box
A box containing these instruments and products should be available in every
hospital, providing emergency surgical care. (* materials are considered extremely
important)
1. A standard set of surgical instruments* including: non-crushing vascular
clamps* of various sizes, self-retaining retractors*, fine non-toothed vascular
forceps*, fine scissors* or angled Potts scissors.
2. Rummel tourniquets, surgical rubber loops *or other means of atraumatically
controlling small vessels.
3. Prolene sutures* with non-cutting needles – 2-0, 3-0, 4-0, 5-0
3. Fogarty catheters* – sizes 3-5
4. Heparin* to make a solution of 1000units/20 ml NS for local irrigation. For
systemic heparinization the dose is 100units/kg, but this might require reversal
with protamine sulfate.
5. Papaverine for intra-arterial injection or xylocaine* for topical adventitial
administration to counteract spasm in smaller vessels.
6. Equipment for hand-held intra-operative angiography including soluble intravenous
contrast*, syringes, intra-venous cannulae.
Brian Ostrow MD, FRCS(C)
Guelph, Canada
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| Clinical cases | |
| Brachial artery injury | |
| False Aneurysm of Popliteal Artery | |
| False Aneurysm of Femoral Artery | |
| Arterio-Venous Fistula of Femoral Vessels | |
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