Spinal Fluid Drainage in Thoracoabdominal Aortic Aneurysm Repair: The Complications

Thoracoabdominal aortic aneurysm (TAAA) repairs are necessary to treat thoracic aneurysms. Classified as major surgery, the procedure involves opening the subject’s chest and replacing the weak part of the aorta wall with a grafted fabric tube. On average, successful operations to repair ruptured aortic aneurysms of this type tend to yield a further life expectancy of five to six years.

During the intervention, surgeons usually opt to drain cerebrospinal fluid (CSF). Draining spinal fluid reduces the risk of paraplegia in patients who undergo a TAAA repair, thanks to relief in pressure and increased perfusion, i.e. blood flow. Maintaining a healthy level of spinal perfusion prevents ischaemia, the medical term for restrictions in blood supply to tissues and – consequently – a harmful shortage of oxygen.

When the circulation of blood in the lumbar and internal iliac arteries suffers interruption, the resulting ischaemia in the anterior column of the spine interferes with the transmission of nerve signals and movement in the lower limbs. To prevent such interference during and after operations on the thoracic aorta, surgical teams aim to maintain adequate blood flow and, therefore, reduce the risk of uncommon but devastating problems.

Following the induction of general anaesthesia, the surgical team positions the patient with care, before placing the drain on the right side of his or her back. Afterwards, they leave the spinal drain in place during the early stages of recovery.

Whereas draining CSF after aneurysm repair reduces the likelihood of complications and spinal injury, it has the following risks:

• Occlusion. Suppose the drain does not work correctly due to blockage in the spinal canal. In that case, the correspondingly reduced blood flow may result in infarction (a stroke) inside the column.
• Bleeding. Too much drainage of CSF can cause bleeding within the spinal cord or the brain. Symptoms include headache, neurological trauma and intradural or epidural haematoma with nerve damage.
• Infection and abscesses, in proportion to the longer a drain remains in situ. In such cases, antibiotic therapy and further drainage of the infected area will become necessary.

Recommendations

To minimise the occurrence of the above difficulties, medical experts advocate the strict management of spinal drains, preferably in high dependency or intensive care units. Nursing staff ought to receive adequate training and specific instructions regarding drain management from the surgeon in charge in each case.

Finally, a group of leading anaesthetists recommends that among other precautions, the postoperative management of TAAA surgical patients should include regular assessment and observation of their neurological condition. In a paper published by the US-based National Center for Biotechnology Information, the doctors note the importance of managing spinal cord perfusion pressure (SCPP) via blood pressure and CSF drainage.