Thoracoabdominal aortic surgery and spinal cord protection

Model answer

Protection (5). Cord perfusion pressure is MAP minus CSF pressure (or CVP if higher): raise MAP, drain CSF to 10 mmHg or less, optimise haemoglobin, limit ischaemic time, monitor MEP/SSEP, reimplant critical segmental arteries, and use distal perfusion where available. Drainage improves cord perfusion pressure but carries neuraxial and intracranial bleeding risk.

Scale of risk (5). In 1114 extent II open repairs, cord deficit followed 13.6% (86 persistent at 7.7%, 65 transient at 6.1%), with delayed persistent deficit in 3.5%; segmental reattachment protected (relative risk ratio 0.38). After TEVAR, cord ischaemia affected 3.89% of 4936 patients across 46 studies, and the prophylactic-drain role remains difficult to establish.

Delayed (5). Delayed leg weakness is a crash call: raise MAP immediately, check the drain is working with CSF pressure low, optimise haemoglobin, exclude haematoma, activate the cord ischaemia pathway — never wait for morning radiology.