Extremity Trauma


Vascular Injuries

  1. Mechanism of injury
    • transection and lateral lacerations are the usual forms of vascular injury in penetrating trauma
    • fracture of the intima with obstruction and thrombosis is the usual mechanism of arterial injury in blunt trauma

  2. Clinical Manifestations
    1. ‘Hard Signs’
      • external pulsatile bleeding
      • expanding hematoma
      • palpable thrill or audible bruit
      • pulselessness
      • overt ischemic changes

    2. ‘Soft Signs’
      • history of prehospital hemorrhage
      • diminished (but present) pulses
      • nonexpanding hematoma
      • wounds in proximity to a major artery
      • fracture or dislocation

  3. Evaluation
    1. ‘Hard Signs’ Present
      • most patients undergo operative exploration without additional studies
      • arteriography may play an adjunctive role when the level of injury is unclear or if multiple injuries are present
      • arteriography may be performed intraoperatively if the patient has other life-threatening injuries or has an ischemic limb
      • CTA is less time-consuming and costly than conventional arteriography

    2. ‘Soft Signs’ Present
      • several different management scenarios are possible

      1. Observation
        • patient is admitted for serial physical exams and Doppler arterial pressure measurements
        • a Doppler ankle/brachial index of <0.9 is considered abnormal and mandates further workup, usually with a CTA

      2. Routine Imaging
        • arteriography or CTA is sensitive and specific for diagnosing vascular injuries
        • Duplex imaging is not used in the acute setting (wounds, swelling, dressings make getting useful images difficult)

  4. Nonoperative Management of Minimal Vascular Injury
    1. Intimal Flaps
      • small, nonocclusive intimal flap is the most common clinically insignificant vascular injury
      • likelihood that it will progress to occlusion or distal embolization is 10% - 15%
      • progression, if it occurs, will be early in the postinjury course

    2. Small Pseudoaneurysms
      • more likely to progress to need repair
      • can be followed with Duplex imaging

    3. Spasm
      • usually resolves promptly
      • failure to resolve means that a more serious vascular injury is present

  5. Endovascular Management
    • use of stent grafts in the extremities is becoming more common
    • long term results, however, have not been documented
    • autologous vein interposition grafts remain the gold standard for vascular repairs in the extremities
    • larger pseudoaneurysms are best managed with open techniques since thrombosis or distal embolization is high with endovascular techniques

  6. Operative Management
    1. Preoperative Considerations
      • must document preoperative extremity neurologic status
      • a new neurologic deficit after vascular repair merits investigation and possible re-exploration
      • orthopedics and plastic surgery may need to be involved to manage associated bone and soft tissue injuries

    2. Proximal Control
      • direct pressure provides the best initial control
      • blind clamping should never be done
      • tourniquets may be used judiciously

    3. Exposure
      • prep widely – may need to get proximal control in the chest or abdomen
      • uninjured leg should be prepped for vein harvest
      • incisions for proximal and distal control should be placed away from the hematoma

    4. Repair
      1. Damage control
        • chosen when there are concomitant life-threatening injuries
        • ligation should be reserved for vessels with adequate collateral flow (axillary artery, radial or ulnar artery, profunda, one infrapopliteal artery)
        • a temporary intraluminal shunt should be used if ligation will cause distal ischemia

      2. Definitive Arterial Repair
        • fractures or dislocations should be reduced first
        • some injuries are amenable to end-to-end repair or lateral repair
        • most injuries will require an interposition graft for repair
        • autologous greater saphenous vein from an uninjured leg is the best graft material (not thrombogenic, has superior patency rate in smaller vessels such as the popliteal or tibial arteries)
        • if autologous saphenous vein is not available, then PTFE may be used proximal to the popliteal
        • routine completion arteriography should be done following vascular repair and will detect important clinical findings in 10% of patients
        • patients should be maintained on aspirin and followed long-term for post-op surveillance

        1. Axillary Artery
          • may be disrupted in blunt trauma when there is tearing of the shoulder girdle
          • usually requires a saphenous vein interposition graft
          • in rare cases, ligation and fasciotomy are needed

        2. Brachial artery
          • preferred treatment is simple suture repair or saphenous vein interposition graft
          • found in the groove between the biceps and triceps muscles

        3. Radial or Ulnar Artery
          • if injured separately, repair is not necessary because there is excellent collateral circulation
          • if both are injured, at least one must be repaired

        4. Common Femoral Artery
          • should be repaired if possible
          • exposed with a vertical incision over the inguinal ligament halfway between the pubic tubercle and the anterior iliac spine
          • saphenous vein or PTFE can be used if simple repair is not possible
          • profunda can be ligated since there are excellent collaterals around the hip

        5. Superficial Femoral Artery
          • should be repaired
          • exposed my making an incision over the anterior border of the sartorius muscle
          • most injuries will require a saphenous vein interposition graft
          • fasciotomy will likely be necessary

        6. Popliteal Artery
          • high risk of injury after posterior knee dislocation – need CTA even if distal pulses are present
          • may be exposed from a medial or posterior approach
          • fasciotomy usually necessary after popliteal repair

        7. Infrapopliteal Vessels
          • injury to one vessel rarely results in limb ischemia
          • anterior and posterior tibial arteries should be repaired in stable patients using size-matched reversed saphenous vein
          • peroneal artery rarely requires repair

      3. Venous Injuries
        • most can be ligated
        • repair should be reserved for large veins in stable patients
        • incidence of postoperative thrombosis is high
        • if the external iliac, femoral, or popliteal vein is ligated, then fasciotomy should be performed at the same time

Fractures and Dislocations

  1. Fractures
    • multiple long bone fractures have a strikingly adverse impact on survival following multiple trauma

    1. Diagnosis
      • pain, swelling, deformity, tenderness, crepitus, and abnormal motion at the fracture site are the usual findings
      • some degree of soft tissue injury is also usually present
      • vascular and/or neurologic injury may be present
      • if an open wound is present in the same limb segment, the fracture is considered open

    2. Management
      • the fracture must be reduced and immobilized, including the joints above and below the fracture
      • open fractures should be covered with a sterile dressing, tetanus prophylaxis and broad-spectrum antibiotics administered, and operative debridement, irrigation, and fracture stabilization performed as soon as the life-threatening injuries have been corrected
      • early fracture stabilization decreases the incidence of ARDS, fat embolization syndrome, and the subsequent development of sepsis and multi-organ failure

  2. Dislocations
    1. Diagnosis
      • deformity of the extremity is usually present
      • significant neurologic injury is common after certain dislocations (posterior hip dislocation → sciatic nerve compression; posterior shoulder dislocation → axillary nerve injury

    2. Management
      • reduction often requires IV sedation to reduce muscle spasm
      • reduction technique requires recreating the injury, gentle traction, and reversal of the injury

      1. Posterior Hip Dislocation
        • thigh is flexed and internally rotated
        • sciatic nerve injury and avascular necrosis result from delay in treatment
        • avascular necrosis may result in the need for a total hip replacement
        • if the hip remains dislocated for 24 hours, the incidence of avascular necrosis is 100%
        • reduction within 6 hours reduces the incidence of ischemic changes

        Posterior Hip Dislocation
      2. Posterior Knee Dislocation
        • common cause of popliteal artery injury
        • prompt reduction is mandatory, as well as vascular evaluation
        • CTA has 100% specificity and sensitivity for detecting clinically relevant popliteal injury

        Posterior Knee Dislocation

Compartment Syndrome

  1. Pathophysiology
    • elevated pressure within a closed fascial space
    • elevated compartment pressure may result from an increase in compartment contents or a decrease in compartment volume
    • elevated compartment pressure → microvascular compromise → ischemia → muscle and nerve necrosis → loss of function, limb loss
    • common causes include acute trauma (especially high-velocity or crush injuries), vascular injury, reperfusion injury after prolonged ischemia, burns, electrical injury, and external compression by casts or tight dressings
    • most common areas where compartment syndrome develops are the lower leg and forearm (tibial and forearm fractures); less common areas include the hand, foot, buttock, and thigh

  2. Diagnosis
    • high index of suspicion is required, especially in patients with an altered mental status
    • signs and symptoms include the six Ps: pain out of proportion, pressure (swelling, hardness), pain with stretching, paresis, paresthesias (most reliable physical finding), pulselessness (rare)
    • a palpable distal pulse is usually present and capillary refill is within normal limits
    • late signs of compartment syndrome include weakness, paralysis, and loss of pulses

    1. Compartment Pressures
      • fasciotomy may be performed based on clinical examination findings
      • however, measuring compartment pressures can be a useful adjunct to physical exam, especially if the exam is unreliable because of head injury, intoxication, spinal cord injury, or nerve or artery damage
      • commercial products exist that can directly measure muscle tissue pressure (Stryker)
      • normal muscle compartment pressure is less than 20 mm Hg
      • tissue pressures > 40 mm Hg mandate immediate fasciotomy
      • pressures between 30 and 40 mm Hg are in a gray zone, and fasciotomy should be performed in most of these patients
      • systemic blood pressure must also be considered: the lower the blood pressure, the lower the compartment pressure that causes a compartment syndrome
      • all 4 compartments should be measured in the leg

  3. Anatomy of the Lower Leg Compartments
    1. Anterior Compartment
      • contains the anterior tibial artery, deep peroneal nerve, and extensor muscles of the toes and foot
      • deep peroneal nerve may be tested by documenting sensation at the first web space of the foot

    2. Lateral Compartment
      • contains the superficial peroneal nerve and the peroneal brevis and longus muscles
      • superficial peroneal nerve may be tested by documenting sensation on the dorsum of the foot
      • peroneal brevis and longus muscles plantar flex and evert the foot

    3. Superficial Posterior Compartment
      • contains the gastrocnemius and soleus muscles, which plantar flex the foot

    4. Deep Posterior Compartment
      • contains the tibial nerve, posterior tibial artery, peroneal artery, and the deep toe and foot flexor muscles
      • tibial nerve is responsible for sensation on the plantar surface of the foot

  4. Management
    • tight dressings should be removed and casts bivalved
    • all 4 compartments of the leg must be released
    • fasciotomy may be performed through a single-incision or double-incision technique
    • wounds are left open and covered with sterile dressings
    • if the wounds cannot be closed primarily within 7 days, split-thickness skin grafts should be applied

    Four Compartment Fasciotomy
    Four Compartment Fasciotomy

Traumatic Rhabdomyolysis

  1. Pathophysiology
    • most commonly occurs following a crush injury, although it may occur following major vascular injury, burns, or compartment syndrome
    • myoglobin is released into the circulation following extensive muscle injury
    • myoglobin is filtered in the kidneys and precipitates in the renal tubules, obstructing tubular flow → acute renal failure

  2. Diagnosis
    • myoglobinuria produces dark amber urine that tests positive for hemoglobin, but no red cells are seen on urinalysis
    • a specific assay for myoglobin exists, but results are frequently delayed
    • CPK > 10,000 indicates a patient at high risk for developing acute renal failure

  3. Management
    • aggressive hydration to keep urine flow > 200 cc/hr
    • mannitol may be added to improve urine flow
    • alkalization of the urine with sodium bicarbonate reduces intratubular precipitation of myoglobin
    • diuretics that decrease urine pH (Lasix) should be avoided







References

  1. Cameron, 11th ed., pgs 1109 - 1117
  2. Sabiston, 20th ed., pgs 478 – 487, 1808 – 1822
  3. ATLS 10th ed., pgs 148 -167