202412092135
Status:
Lumbar drain
for TAAA surgery
typically 8-10cm catheter in space
Ischemic spinal cord injury occurs during aortic repair due to extensive or prolonged occlusion of the blood vessels that perfuse the spinal cord and arise from the aorta
The theory behind the protective effect of CSF drainage against ischemic spinal cord injury is based on the Spinal Cord Perfusion Pressure equation
(spinal cord perfusion pressure = MAP – intraspinal pressure)
By draining CSF, the intraspinal pressure decreases, allowing for increased spinal cord tissue perfusion and oxygenation during transient aortic and permanent segmental artery occlusions
Randomized controlled trials in open repair have been supportive of this protective effect, and CSF drainage is now a widely accepted, guideline-driven prophylactic and rescue therapy in open surgical repair patients at high risk of spinal cord ischemia
utility of CSF drains as a protective measure in TEVAR has not been evaluated through randomized controlled trials, making their efficacy in this setting far less clear
In theory, only patients at high risk of spinal cord ischemia from TEVAR should be candidates for prophylactic CSF drainage. This is because intrathecal catheter insertion is not a benign procedure and can lead to major complications (such as neuraxial hematoma, paralysis, intracranial hemorrhage and even death) in up to 3.5% of cases
overall falling rates of spinal cord ischemia in TEVAR over time as seen in the Vascular Quality Initiative database may reflect the advancement in surgical techniques optimized to prevent spinal cord ischemia
The core knowledge gap surrounding the role of CSF drainage includes not just their overall efficacy and complications, but also the optimal timing of CSF drain placement
prophylactic vs rescue
rescue CSF drainage may not be as effective as prophylactic CSF drainage when it is not inserted in a timely fashion following spinal cord ischemia diagnosis
definitions of what constitutes “high risk” often vary greatly between publications
(no consensus)
anatomical based risk assessment e.g.
- long aortic coverage
- coverage of origin of Adamkiewics artery (T9-12)
- involvement of collaterals
rescue therapy itself has been suggested to be associated with a higher risk of drain complications
preoperative drain placement reduces the risk of overall drain complications. The reasons for this are likely related to the lower urgency of placement or other patient risk factors ( e.g. , postoperative coagulation abnormalities, imperfect patient positioning).Prophylactic CSF drain placement has multiple advantages that can potentially reduce the rates of complications. Placing drains preoperatively may give providers more time and resources to better deal with difficult lumbar drain insertion. In addition, prophylactic drain placement gives the opportunity for any insertion-related complications to be detected prior to the start of surgery
Though there are no specific data available in the setting of lumbar CSF drainage for guidance, it would seem prudent that the INR should be at minimum less than 1.5 prior to drain placement or removal
ASRA does not suggest a specific safe platelet count threshold for providers to consider when assessing the risk of neuraxial bleeding from spinal or epidural puncture
Currently, most protocols call for a drain overflow (or “pop-off”) pressure of ==10 mmHg ==and/or a maximum drainage volume of 10 to 15 ml/h of CSF. However, these values lack empirical clinical evidence. It has been reported that excessive CSF drainage has been linked to intracranial hemorrhage and subdural hematoma formation due in part to the tearing of dural bridging veins that are stretched and torn by the intracranial hypotension that can result from excessive CSF drainage
Unlike CSF pressure management, guidelines have been published in 2024 addressing MAP management in patients with traumatic spinal cord injury. While these guidelines are related to traumatic rather than ischemic spinal cord injury, it provides at least some indirect blood pressure guidance.
These recommendations include maintaining a minimum MAP of 75 to 80 mmHg with a maximum range of 90 to 95 mmHg. However, the guidelines acknowledge that the evidence supporting these recommendations was “very low,” and thus the strength of the recommendation was weak.
Equally notable, there was no specific recommendation for the use of vasoconstrictors or inotropes to optimize blood pressure management.
endovascular repair may have different pathophysiological mechanisms of injury than those seen in open repair
Post-op
monitoring in HDU / ICU
keep drain for at least 48 hours (high risk period)
↑ risk of infection if kept >5 days
References
Spinal cord protection in aortic endovascular surgery - British Journal of Anaesthesia
Spinal Cord Protection in Aortic Endovascular Surgery - BJA Ed
Perioperative Management of Thoracic and Thoracoabdominal Aneurysms - BJA Ed
Lumbar Spinal Drains for Thoracoabdominal Aortic Surgery - ATOTW