32 EXTREMITY VASCULAR INJURIES
Kyle H. Mueller M.D., William H. Pearce M.D.

1. What are the “hard signs” of arterial injury?

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* Distal circulatory deficit: ischemia or diminished or absent pulses
* Bruit
* Expanding or pulsatile hematoma
* Arterial (pulsatile) bleeding

2. What are the four ways in which an arterial injury may present?

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1. Hemorrhage
2. Thrombosis
3. Arteriovenous fistula
4. Pseudoaneurysm

3. What are the “soft” signs of arterial injury?

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* Small- or moderate-sized stable hematoma
* Adjacent nerve injury
* Shock not explained by other injuries
* Proximity of penetrating wound to a major vascular structure

4. What are the symptoms of acute arterial occlusion?

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The six P’s: pain, pallor, pulse deficit, paresthesia, paralysis, and poikilothermia (cold).

5. What initial screening test is used to evaluate an extremity for occult vascular injury?

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Calculation of arterial pressure indices (APIs).

6. What are the APIs for the upper extremity and lower extremity called?

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An API for the upper extremity is the wrist brachial index (WBI).
An API for the lower extremity is the ankle brachial index (ABI).

7. How are WBI and ABI measured, and what is considered a normal value?

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A hand-held Doppler and blood pressure cuff are used to measure systolic blood pressure in the brachial, radial, ulnar, dorsalis pedis (DP), and posterior tibial (PT) arteries bilaterally. The ABI for each leg is the highest DP or PT divided by the highest brachial pressure. The WBI for each arm is the highest radial or ulnar artery pressure divided by the highest brachial pressure. A value of 1.0 is normal.
8. What API value raises concern for arterial injury, and what is the sensitivity and specificity? Show answer

* An API value < 0.9 has a sensitivity of 95% and specificity of 97% for major arterial injury.
* An API > 0.9 has a negative predictive value of 99%.

9. When the API value is < 0.9 in an injured extremity, what should be the next diagnostic test?

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Arteriography to establish the diagnosis and plan for operative intervention.

10. What abnormalities on arteriography determine a positive test result?

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* Obstruction of flow
* Extravasation of contrast
* Early venous filling or arteriovenous fistula
* Wall irregularity or filling defect
* False aneurysm (pseudoaneurysm)

11. What study should be performed for patients with proximity injury or soft signs (API > 0.9)?

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Duplex ultrasonography to rule out occult vascular injury.

12. What occult vascular injuries can be detected by duplex ultrasonography?

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* Intimal flap
* Pseudoaneurysm
* Arteriovenous fistula
* Focal vessel narrowing
* Nonoperative observation of these injuries is safe and effective: 89% of them do not require surgery

13. What is a pseudoaneurysm?

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It is a disruption of the arterial wall leading to a pulsatile hematoma contained by fibrous connective tissue (but not all three arterial wall layers). (See Figures 32-1 and 32-2.)

Figure 32-1 Subtraction angiography demonstrating intimal flap with stenosis of superficial femoral artery.

Figure 32-2 Duplex ultrasound of common femoral artery demonstrating pseudoaneurysm sac and associated neck between pseudoaneurysm sac and femoral artery after percutaneous access for angiography.

14. What is a true aneurysm?

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Dilatation of all three layers of the vessel wall (i.e., intima, media, and adventitia).

15. What is the most effective way to control arterial bleeding in an injured extremity?

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Direct digital pressure.

16. What means of controlling vascular injury should be avoided? Why?

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A tourniquet should be avoided because collateral circulation is occluded and leads to increased tissue ischemia.
Blind clamping should also be avoided because it causes further vessel damage, making reconstruction more difficult.

17. How should a patient with an extremity vascular injury be prepared and draped in the operating room?

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The entire involved extremity should be in the sterile field. The major arterial trunk proximal to the site of injury (for proximal control) and a portion of lower extremity permitting access to saphenous vein should be included in the sterile field.

18. What else should be prepared and draped for proximal extremity injuries?

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The chest should be prepped for proximal injuries of the upper extremity. The abdomen should be prepped for proximal injuries of the lower extremity. (Access to the chest or abdomen may be necessary to obtain proximal vascular control.)

19. What are the operative principles relative to repair of vascular injuries?

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* Perform longitudinal incisions over vessels to be explored.
* Initial dissection should be away from the site of suspected injury and adjacent hematoma.
* Obtain proximal and distal control of the injured vessel.
* Debride the injured vessel.
* Perform primary repair if tension free (fully extend extremity to ensure tension-free repair).
* Repair with autogenous interposition vein graft if there is inadequate length (tension).

20. What is the best conduit to use if primary repair is not possible? Why?

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Saphenous or cephalic vein from the uninjured extremity to preserve venous flow.

21. Should injuries to major veins of the extremities be repaired?

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Yes. Repair of a major vein enhances the success of a concomitant arterial repair by improving outflow. Late thrombosis often occurs after venous repair, but initial patency helps by allowing collateral circulation to develop. This may also reduce the incidence of postoperative venous insufficiency.

22. When should injured major veins be ligated?

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Major veins should be ligated rather than repaired when the patient is hemodynamically unstable or the repair is too complex.

23. What complications can develop after ligation of major extremity veins?

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Possible complications include rapid increase in muscle compartment pressure, leading to compromised venous or arterial flow and compartment syndrome. Also, postoperative venous stasis may occur, which can be alleviated with intermittent pneumatic calf compression and leg elevation.

24. What is a compartment syndrome?

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Development of pathologically elevated tissue pressures (preventing perfusion) within nonexpansile envelopes (inside fascial compartments) of the arm or leg.
KEY POINTS: COMPARTMENT SYNDROME

1. Pathologically elevated tissue pressures in nonexpansile fascial compartments prevent tissue perfusion.
2. The most common cause is ischemia-reperfusion injury following traumatic extremity injuries.
3. The earliest clinical sign is numbness in the first dorsal webspace associated with compromise of the deep peroneal nerve. Other signs: pain with passive joint motion, pain out of proportion to injury, tense and tender muscle compartments.
4. Distal pulses are evident until late in the diagnosis and should not be used to rule out compartment syndrome.
5. Hand-held manometer is used to measure muscular compartments. Normal pressure = < 10 mmHg; pathologic pressure = > 30 mmHg.
6. Treatment is emergent fasciotomy.

25. What is the most common cause of a compartment syndrome?

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Ischemia-reperfusion injury when ischemia depletes intracellular energy stores and then reperfusion leads to toxic oxygen radicals, causing cellular swelling and interstitial fluid accumulation.

26. What is the earliest sign of compartment syndrome after vascular repair of an extremity?

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Neurologic deficit in the distribution of the peroneal nerve with weak dorsiflexion and numbness in the first dorsal webspace.

27. Are there any other signs of a developing compartment syndrome of an extremity?

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* Increased pain with passive motion of the ankle
* Pain out of proportion to clinical findings (ischemia hurts)
* Tense muscle compartments that are tender to palpation

Distal pulses can remain intact.
28. How is the objective diagnosis of a compartment syndrome made?

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By measuring compartment pressures with a percutaneous needle and pressure transducer. Criteria for compartment syndrome are as follows:

* When diastolic pressure-compartment pressure is ≤ 20 mmHg or
* When mean arterial pressure-compartment pressure is ≤ 30 mmHg

29. What is the treatment for compartment syndrome of an extremity?

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Emergent fasciotomy, with decompression of the four compartments of the lower leg (anterior, lateral, superficial posterior, and deep posterior) or decompression of the forearm compartments.

30. What is the result of untreated compartment syndrome?

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Loss of perfusion promotes eventual myoneuronecrosis.
31. Which are the most commonly injured arteries in the upper extremity?

Brachial artery	30% (most frequently caused by catheterization for arteriography)
Radial or ulnar artery	20%
Axillary artery	10%
Subclavian artery	5%

32. Which are the most commonly injured arteries in the lower extremity?

Superficial femoral artery	20%
Popliteal artery	10%
Common femoral artery	< 5%
Anterior, posterior tibial, and peroneal arteries	< 5%
Deep femoral artery	2%

33. Can a patient with an extremity arterial injury have palpable distal pulses?

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Yes. In ≤ 20% of proven arterial injuries, a distal pulse is palpable (often because of collateral circulation).

34. What orthopedic injuries commonly have associated vascular injuries?

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* Supracondylar humerus fractures are associated with brachial artery injuries.
* Knee dislocations are associated with popliteal artery injuries.
* Femur fractures can be associated with injury to the superficial femoral artery.

35. For an injured extremity with concomitant fracture and vascular injury, which repair should be performed first?

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The vascular repair should be performed first to restore flow and reverse tissue ischemia.

36. After reducing or fixing an extremity fracture, what must you always do?

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Evaluate the distal pulses to ensure adequate vascular inflow (especially if fixation or any manipulation follows a vascular repair).

37. What is the likely diagnosis in a patient with repetitive palmar trauma and finger ischemia or necrosis?

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Hypothenar hammer syndrome (HHS). The mechanism is thought to be repetitive palmar trauma in patients with preexisting palmar artery fibrodysplasia. (The arteriogram shows digital artery occlusions with segmental ulnar artery occlusion or “corkscrew” elongation.) (See Figure 32-3.)

Figure 32-3 Angiography demonstrating intimal flap in superficial femoral artery associated with femur fracture.

38. What complications can occur after angiography when a percutaneous closure device is used on the femoral artery?

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* Thrombosis, ischemia, or both when the closure suture involves the posterior wall (back wall) of the artery
* Infected pseudoaneurysm
* Distal embolization when a hemostatic plug closure device is used

References
WEB SITES

1. http://www.east.org/tpg/lepene.pdf
2. http://www.surgery.ucsf.edu/eastbaytrauma/Protocols/ER%20protocol%20pages/extremity.htm

BIBLIOGRAPHY
1. Ferris BL, Taylor LM Jr, Oyama K, et al: Hypothenar hammer syndrome: Proposed etiology. J Vasc Surg 31:104-113, 2000. Medline Similar articles
2. Rutherford RB (ed): Vascular Surgery, 5th ed. Philadelphia, W.B. Saunders, 2000, pp 862-870.
3. Schwartz SI (ed): Principles of Surgery, 7th ed. New York, McGraw-Hill, 1999, pp 158-177.