Incidence of Post-Perfusion Ischemia After Decompression Cervical Surgery for Severe Myelomalacia
Post-perfusion ischemia (also known as "white cord syndrome") is a rare complication occurring in approximately 4-9% of patients undergoing decompression surgery for severe cervical myelomalacia. 1, 2
Pathophysiology and Mechanism
Post-perfusion ischemia after cervical decompression represents a reperfusion injury to chronically ischemic areas of the spinal cord. This occurs through the following mechanism:
- Chronic compression causes long-standing ischemia in the spinal cord tissue
- Sudden decompression leads to rapid restoration of blood flow
- The reperfused tissue experiences oxidative stress and inflammatory damage
- This results in worsening neurological symptoms despite successful surgical decompression
The radiographic hallmark is increased T2 hyperintensity in the spinal cord on post-operative MRI without other pathologic changes 1.
Risk Factors
Several factors appear to increase the risk of developing post-perfusion ischemia:
- Severe preoperative myelomalacia on MRI
- Advanced age (particularly over 75 years)
- Longer duration of symptoms before treatment
- More severe preoperative neurological dysfunction
- Presence of abnormal EMG findings 3
Clinical Presentation
Post-perfusion ischemia typically presents as:
- New or worsened neurological deficits immediately after an otherwise uncomplicated decompressive procedure
- Symptoms may include hemiparesis, quadriparesis, or other focal neurological deficits
- Symptoms occur despite radiographic evidence of adequate decompression 1
Incidence in Research
The literature shows that post-perfusion ischemia is relatively rare:
- In the AOSpine North America CSM study, approximately 9.3% of patients exhibited postoperative functional decline
- About 4% of patients experienced perioperative neurological complications within 20 days after surgery in otherwise uneventful surgeries 2
- Upon literature review, "white cord syndrome" has been reported in only a handful of cases (5-7 cases documented) 1
Management of Post-Perfusion Ischemia
When post-perfusion ischemia occurs, management typically includes:
- Maintaining mean arterial pressure (MAP) goals to ensure adequate spinal cord perfusion
- Administration of high-dose corticosteroids
- Intensive physical therapy and rehabilitation 1
Prognosis
Most patients with post-perfusion ischemia show improvement with appropriate management:
- All but one patient reported in the literature improved after MAP goal maintenance, steroid administration therapy, and acute rehabilitation 1
- However, 44% of patients undergoing decompression for cervical spondylotic myelopathy are left with substantial neurological impairment 6 months postoperatively 2
Prevention Strategies
Emerging research suggests potential preventive approaches:
- Riluzole (an FDA-approved drug) has shown promise in animal models by attenuating oxidative DNA damage in the spinal cord and reducing postoperative decline after decompression surgery 2
- Careful surgical technique with gradual decompression may help minimize sudden reperfusion
- Maintaining stable blood pressure during and after surgery
Important Considerations
Despite the risk of post-perfusion ischemia, it's important to note that:
- All patients with preoperative myelomalacia in one study had residual spinal cord abnormalities after decompression, indicating irreversible changes 4
- However, there was no difference in clinical improvement between patients with or without myelomalacia, suggesting that decompression can still provide clinical benefit despite persistent MRI changes 4, 5
- Surgical decompression remains the recommended treatment for moderate to severe cervical spondylotic myelopathy, with benefits maintained for 5-15 years postoperatively 3
In conclusion, while post-perfusion ischemia is a recognized complication of cervical decompression surgery for severe myelomalacia, its incidence is relatively low (4-9%). Spine surgeons should be aware of this potentially serious complication and be prepared to manage it appropriately with MAP goals, steroids, and rehabilitation.