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Page 2 of 16 Gomes et al. Vessel Plus 2023;7:24 https://dx.doi.org/10.20517/2574-1209.2023.60

[3]
Bickerstaff et al. have estimated the incidence of TAAA at 0.37 cases per 100.000 per year . New cases of
[4]
both TAA and TAAA are increasing due to the longevity of the population and the early detection of these
pathologies, facilitated by the improvement in diagnostic tools. Spinal cord ischemia (SCI) is by far the most
severe and devastating adverse event that can occur following the surgical repair of TAA or TAAA, as it
significantly impacts the postoperative morbidity and mortality of these patients. Coselli et al., in a study
[5]
considering 1,114 type II TAAA cases, observed an incidence of postoperative SCI of 13.6% . Patients with
permanent paraplegia had poorer midterm survival (51.7% ± 4.2% at 3 years) compared to those without
spinal ischemia after the repair (75.8% ± 1.4%). Spanos et al., in a study including 243 patients with complex
anatomy aortic aneurysms undergoing endovascular repair, reported a 30-day mortality rate of 6.1% among
the cases with postoperative paraparesis, and up to 40% in patients who developed postoperative
[6]
paraplegia . The present literature review aims to analyze the critical risk factors for SCI in the context of
aortic surgery, to explore the most relevant strategies for the prevention of this adverse event during the
treatment of TAA and TAAA, and to discuss the management strategy recommended for the patients who
develop SCI associated with their repair.

INCIDENCE OF SCI AFTER TAA AND TAAA REPAIR
The open surgery techniques have substantially evolved since the successful repairs of TAA and TAAA, as
[9]
reported by DeBakey, CooleyField , and EtheredgeField . However, the risk of spinal cord ischemia
[7,8]
remains significant [Table 1].
Initially indicated only for patients with numerous comorbidities who were not suitable candidates for open
procedures, endovascular repair has become the approach of choice in the treatment of complex anatomy
aneurysms at centers of excellence , and is currently recommended by the Clinical Practice Guidelines
[17]
[18]
published by the European Society for Vascular Surgery in 2019 . Prior published studies indicate that the
risk of SCI associated with aortic surgery ranges from 3%-14% [Table 1].

SPINAL CORD BLOOD SUPPLY REVIEW
The spinal cord arterial supply is composed of a complex network connecting multiple vessels responsible
for its blood supply, such as the vertebral arteries (VA), the intercostal and lumbar arteries, and the
hypogastric arteries. Biglioli et al., in an experimental study with cadavers, described the collateral pathways
that contribute to spinal cord perfusion . Three arteries run longitudinally along the length of the spinal
[19]
cord, including one anterior spinal artery (ASA) and two posterior spinal arteries (PSA). The anterior spinal
artery originates by the level of the foramen magnum and is responsible for the irrigation of the two
anterior thirds of the spinal cord. The two posterior spinal arteries (PSA) originate either from the vertebral
[20]
arteries or posterior inferior cerebellar arteries . The spinal arteries are primarily fed by the subclavian and
vertebral arteries in the cervical segment of the spine. Segmental arteries in the thoracic and lumbar regions
provide additional blood supply to the spinal arteries , and the Adamkiewicz artery, which is the largest
[21]
anterior segmental vessel, branching off the left side of the distal thoracic or proximal abdominal aorta
between T8 and L2 in 75% of people. The primary blood flow supply for the distal spinal cord and cauda
equina comes from the hypogastric arteries and their branches . The pial network, which covers the
[22]
entirety of the spinal cord, allows communication between the anterior and posterior spinal arteries .
[23]
More recently, Griepp et al. introduced the collateral network concept, which encompasses the existence of
an extensive network of arteries that supply blood to the cord and paraspinal muscles, presenting the unique
[24]
capability of adapting if faced with interruption . It has been demonstrated that after interruption of
[24]
segmental arteries , an early vasodilation of the ASA is observed, followed by a definitive increment in the
size and density of small arterioles associated with modifications in the direction of the blood flow. This