Spinal cord ischaemia after endovascular thoracic aneurysm repair

Dear Editor:

Spinal cord ischaemia, the most feared postoperative complication of thoracoabdominal aneurysm repair, is a frequent event with a high morbidity and mortality. Its estimated incidence is between 2.7% and 9.5%.¹ Symptoms vary and may appear in both early and late stages. Recovery may be partial or complete. Postoperative management of spinal cord ischaemia is based on measures favouring spinal cord perfusion, mainly haemodynamic optimisation and drainage of cerebrospinal fluid (CSF).¹

We present the case of a 70-year-old man with a history of arterial hypertension (AHT), type 2 diabetes mellitus, obstructive sleep apnoea syndrome (OSAS), chronic kidney disease (CKD) associated with vascular nephropathy in the pre-dialysis stage, and secondary hyperparathyroidism. Our patient was admitted for endovascular repair of a 7-cm thoracic aortic aneurysm near the diaphragm. After he was anaesthetised, we attempted to place a catheter at L3-L4 for CSF drainage but did not succeed in doing so due to technical difficulties. Surgery was performed under balanced anaesthesia after canalisation of the right internal jugular vein and the right radial artery; the latter was used for invasive blood pressure monitoring. During surgery, the patient was infused with 2500 mL of crystalloid solution and required perfusion of norepinephrine (0.05 μg/kg/min) to maintain mean arterial pressure (MAP) around 80 mm Hg. The intervention was conducted without complications; a 10-cm vascular endoprosthesis with 3 stents was placed from the exit of the left subclavian artery, covering the ostium, to the ostium of the celiac trunk. After surgery, the patient was extubated and transferred to the intensive care unit for monitoring. Twenty-four hours after the intervention, our patient experienced sudden-onset symptoms of paraplegia; after a few minutes, he spontaneously recovered movement in the right lower limb but left lower limb monoplegia remained. We ordered an MRI scan to determine whether the complication was haemorrhagic or ischaemic, but the scan was not conducted since the prosthetic device can cause artefacts. We therefore performed a CT scan, which ruled out the presence of epidural haematoma. In view of the radiological findings and the need for rapid action, we performed an additional intervention to place a drainage catheter in the intrathecal space at L4-L5. CSF pressure was 18 mm Hg; 45 mL of CSF were drained in 3 hours. CSF pressure decreased to 11 mm Hg, leading to complete recovery of mobility and strength in the left lower limb.

Acute spinal cord ischaemia is the main suspected diagnosis in cases of sudden onset paraplegia after aortic surgery. Although the prevalence of this complication has decreased in recent years due to the advances in endovascular repair and consequent decline of open surgery, it must not be overlooked. The main risk factors are a stent graft covering ≥25 cm, distal aortic repair (T7-L2), and a history of abdominal aortic aneurysm repair.^1–3 However, several other significant predictors of spinal cord ischaemia have been described, including preoperative kidney disease (independent factor), occlusion of the subclavian or hypogastric arteries, iliac artery injury, placement of 3 or more stent grafts, AHT, and diabetes.^3–6 Multiple studies have confirmed the effectiveness of drainage to protect the spinal cord in both the preoperative and immediate to late postoperative periods. However, unlike in open surgery, placing a CSF drainage catheter is not a standard measure in endovascular treatment¹; preoperative use of these devices is therefore controversial. Prevention strategies include intraoperative monitoring with somatosensory and motor evoked potentials, CSF drainage if available, and maintaining haemodynamic stability (PAM >80 mm Hg).^2–4 Likewise, Matsuda et al.² suggest performing CT angiography or MR angiography scans to identify the artery of Adamkiewicz (the longest intercostal artery, which originates at T8-L1 and supplies the spinal arteries). This serves to prevent unnecessary coverage in cases for which distal aortic repair is indicated.

A neurological examination of these patients is essential during the postoperative period, as it enables early response to any focal neurological signs with potentially fatal consequences. If spinal cord ischaemia is suspected, treatment should aim to include CSF drainage when available and maintain a MAP allowing adequate spinal cord perfusion. Rapid placement of a CSF drainage catheter is the intervention best able to treat this devastating complication, and it therefore has a major impact on the prognosis of these patients.

Conflicts of interest

We followed the instructions for authors when preparing this article, which complies with the ethical standards of the journal. All the authors meet the authorship criteria established by the Elsevier Editorial System. This study has received no funding of any kind. The authors have no conflicts of interest to declare. No personal data from patients have been revealed.