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Difficulty: HardCardiothoracic and Vascular Surgery

A 72-year-old man undergoes an elective thoracic endovascular aortic repair (TEVAR) for an expanding descending thoracic aortic aneurysm. The procedure is technically successful, and no endoleaks are identified on the final angiogram. Four hours after arriving in the intensive care unit, the patient reports a new-onset inability to move his legs. His blood pressure is 110/70 mm Hg, and his heart rate is 86/min. Physical examination reveals 0/5 motor strength in both lower extremities and flaccid muscle tone. There is a complete loss of pain and temperature sensation below the umbilicus. However, proprioception and vibratory sensation are fully preserved in the bilateral toes. Bilateral femoral, popliteal, and pedal pulses are 2+ and symmetric. In addition to optimizing systemic mean arterial pressure, which of the following is the most appropriate next step in management?

  1. A
    Emergent magnetic resonance imaging of the spine
  2. B
    Intravenous administration of high-dose methylprednisolone
  3. Insertion of a lumbar cerebrospinal fluid drainAnswer
  4. D
    Immediate initiation of a continuous heparin infusion
  5. E
    Collection of blood cultures and administration of broad-spectrum antibiotics

Answer

Insertion of a lumbar cerebrospinal fluid drain is the most appropriate next step to increase spinal cord perfusion pressure.
The correct answer is insertion of a lumbar cerebrospinal fluid drain. This patient is presenting with acute anterior spinal cord syndrome, a dreaded and known complication of thoracic endovascular aortic repair (TEVAR). The descending thoracic aorta gives rise to multiple radicular arteries, including the artery of Adamkiewicz (great anterior radiculomedullary artery), which supplies the anterior spinal artery. Exclusion or coverage of these vessels by the stent graft can lead to acute spinal cord ischemia. The anterior spinal artery supplies the anterior two-thirds of the spinal cord (containing the corticospinal and spinothalamic tracts), leading to bilateral motor paralysis and loss of pain and temperature sensation. The posterior columns (mediating proprioception and vibration) are typically spared because they are supplied by the posterior spinal arteries. Immediate management focuses on increasing spinal cord perfusion pressure (SCPP). Because SCPP = Mean Arterial Pressure (MAP) - Cerebrospinal Fluid (CSF) pressure, the most critical initial therapeutic steps are optimizing hemodynamics (raising MAP) and inserting a lumbar drain to lower CSF pressure.

Step-by-Step Solution

1
Analyze the patient's neurological deficits.
The patient has bilateral lower extremity flaccid paralysis (motor loss) and loss of pain/temperature sensation, but preserved proprioception and vibration.
This specific pattern of deficits is the classic presentation of anterior cord syndrome.
2
Correlate the syndrome with the surgical history.
The patient recently underwent TEVAR, which involves placing a stent graft in the descending thoracic aorta.
The artery of Adamkiewicz, a major supplier to the anterior spinal artery, originates from the descending aorta (typically between T8 and L1) and can be inadvertently covered by the stent graft, leading to spinal cord ischemia.
3
Determine the pathophysiological goal of management.
Spinal cord perfusion pressure (SCPP) must be urgently maximized. SCPP is calculated as Mean Arterial Pressure (MAP) minus Cerebrospinal Fluid (CSF) pressure.
Reversing the ischemic injury to the anterior spinal cord depends entirely on rapidly restoring adequate perfusion to the tissue.
4
Select the appropriate clinical intervention.
In addition to increasing MAP (using fluids or vasopressors), placing a lumbar drain to remove CSF will lower the CSF pressure, thereby increasing the SCPP.
This is the definitive emergent bedside treatment for post-TEVAR spinal cord ischemia.

Key Concept

Spinal cord ischemia presenting as anterior cord syndrome is a critical complication of Thoracic Endovascular Aortic Repair (TEVAR). Initial management focuses on maximizing spinal cord perfusion pressure by raising mean arterial pressure and placing a lumbar cerebrospinal fluid drain.
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Topics

Cardiothoracic and Vascular Surgery

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