Postoperative Spinal Cord Ischemia Monitoring: A Review of Techniques Available after Endovascular Aortic Repair

BACKGROUND

Spinal cord ischemia is one of the complications that can occur after open and endovascular thoracoabdominal aortic repair. This occurs despite various perioperative approaches, including distal aortic perfusion, hybrid procedures with extra anatomical bypasses, motor-evoked potential, and cerebrospinal fluid drainage. The inability to recognize spinal ischemia in a timely manner remains a devastating complication after thoracoabdominal aortic repair.This review aims to look at novel technologies that are designed for continuous monitoring to detect early changes that signal the development of spinal cord ischemia and to discuss their benefits and limitations.

METHODS

We conducted a systematic review of the technologies available for continuous monitoring in the intensive care unit for early detection of spinal cord ischemia. Studies were eligible for inclusion if they used different technologies for monitoring spinal ischemia during the postoperative period. All articles that were not available in English were excluded. To ensure that all relevant articles were included, no other significant restrictions were imposed.

RESULTS

We identified 59 studies from the outset to December 2022 to be included in our study. New techniques have been studied as potentially useful monitoring tools that could provide simple and effective monitoring of the spinal cord. These include near-infrared spectroscopy, contrast-enhanced ultrasound, magnetic resonance imaging, fiber optic monitoring of the spinal cord, and cerebrospinal fluid biomarkers.

CONCLUSIONS

Despite the development of new techniques to monitor for postoperative spinal cord ischemia, their use remains limited. We recommend more future research to ensure rapid intervention for our patients.

Spinal cord injury following thoracic and thoracoabdominal aortic repairs

Objective

To discuss the currently available approaches to prevent spinal cord injury during thoracic and thoracoabdominal aortic repairs.

Methods

We carried out a PubMed search up to 2013 using the Medical Subject Headings: “aortic aneurysm/surgery” and “spinal cord ischemia”; “aortic aneurysm, thoracic/surgery” and “spinal cord ischemia”; “aneurysm/surgery” and “spinal cord ischemia/cerebrospinal fluid”; “aortic aneurysm/surgery” and “paraplegia”. All 190 original articles satisfying our inclusion criteria were analyzed for incidence, predictors, and other pertinent variables related to spinal cord injury, and we compared the results in recent publications with those in earlier reports.

Results

The mean age of the 38,491 patients was 65.3 ± 4.9 years. The overall incidence of paraplegia and/or paraparesis was 7.1% ± 6.1% (range 0%–32%). The incidence of spinal cord injury before 2000, from 2001 to 2007, and 2008–2013 was 9.0% ± 6.7%, 7.0% ± 6.1%, and 5.9% ± 5.2%, respectively ( p = 0.019). Various predictors of spinal cord injury were identified, extent of disease being the most common. Modification of surgical techniques, use of adjuncts, and better understanding of spinal cord perfusion physiology were attributed to the decrease in postoperative spinal cord injury in recent years.

Conclusions

Spinal cord injury after thoracic and thoracoabdominal aortic repair poses a real challenge to cardiovascular surgeons. However, with evolving surgical strategies, identification of predictors, and use of various adjuncts over the years, the incidence of spinal cord injury after thoracic/thoracoabdominal aortic repair has declined. Embracing a multimodality approach offers a good insight into combating this grave complication.

Aortic dissection presenting primarily as acute spinal cord damage: a case report and literature review

Acute aortic dissection is a rare, life-threatening condition. Clinical manifestations generally include the acute onset of severe chest or back pain. Aortic dissection presenting with signs and symptoms of acute spinal cord damage is the most severe complication and is particularly rare. This paper reports a case of aortic dissection in a 50-year-old man with a 10-year history of hypertension manifesting as acute spinal cord damage (bilateral lower extremity weakness and loss of all types of sensation), acute skeletal muscle ischaemic necrosis with increased levels of creatine kinase, and acute kidney failure with increased levels of serum creatinine and decreased glomerular filtration rate. The patient refused surgical treatment. His clinical condition progressively worsened and he died 3 days later. This case indicates the importance of considering aortic dissection in patients presenting with acute spinal cord damage, acute skeletal muscle necrosis or acute kidney failure, which may allow early diagnosis and reduce the mortality rate.

A Little Talk on Adamkiewicz's Artery. Some Practical Considerations on the Pre-Operative Identification of this Artery Starting from a Single Team Experience in Pre-Surgical Selective Embolization of Vascularized Spinal Lesions

The major radicular artery eponymically named "Adamkiewicz's artery" (AKA) is an important vessel supplying the spinal cord, especially the lumbar enlargement. This report emphasizes the importance of anatomical knowledge of this artery and highlights the concept of the potential risk of neurological complications during different procedures: spine orthopedic/neurosurgery, aortic repair (vascular surgery) and endovascular selective embolizations performed by interventional neuro/radiologists. Anatomical considerations are made on the spinal cord arterial circulation with a special focus on the AKA. Our review of the literature considered this anatomical element essential to compare the potential risk of spinal cord ischemic damage during orthopedic/neurosurgical spine procedures, aortic vascular surgery repair procedures and endovascular selective arterial embolizations. Evaluation of the endovascular selective arterial spine embolization risk was based on our series of 410 embolization procedures. Spinal cord infarction and transient or permanent paraplegia may result from inadvertent interruption of the AKA. The presence of intersegmental collaterals may decrease the risk of spinal cord ischemia: this is an important element to bear in mind that may help in spine surgery or aortic repair procedures performed by vascular surgeons. Nevertheless, during aortic repair (open surgery or stent-graft procedures) interruption of bilateral segmental arteries at multiple consecutive levels including that of the AKA may occur thereby increasing the ischemic spinal cord risk, annulling the benefit of intersegmental collaterals. Accidental embolizations of the AKA during endovascular spine procedures (i.e. selective arterial embolizations) performed by interventional neuro/radiologists will cause an almost certain spinal cord infarction due to the consequent embolizations of the anterior spinal artery (ASA).

Advances in imaging of the spinal cord vascular supply and its relationship with paraplegia after aortic interventions. A review

INTRODUCTION

Preoperative knowledge of the spinal cord (SC) vasculature could be useful for stratifying and decreasing the risk of perioperative paraplegia after thoracic and thoraco-abdominal aortic surgery. Recent advances in magnetic resonance (MR) and computed tomography (CT) angiography and post-processing techniques have improved this knowledge.

METHODS

A search of MEDLINE/Pubmed and SCOPUS databases identified 1414 pertinent abstracts; 123 full-length manuscripts were screened to identify relevant studies with acceptable design and patient numbers. Forty-three were selected.

RESULTS

SC circulation was studied in 1196 patients to detect the great radicular artery: 522 by MR-angiography and 674 by CT angiography. Detection rates were 67-100% (mean 80.8%) with MR-angiography being 18-100% (mean 72%) with CT angiography. The side and level of the great radicular artery were consistent between the methods. Several authors tried to use the imaging results to guide clinical management.

CONCLUSIONS

Non-invasive imaging of the SC blood supply allows preoperative definition of the vasculature in many, but not all, cases. The impact of these findings on clinical management is potentially beneficial but still uncertain. Further improvements in image acquisition and post-processing techniques are needed. Future studies need to be large enough to compensate for inter-individual variability in SC vasculature in health and disease; however, even a partial reduction of paraplegia rate offers a formidable motivation for further research in this area.

[Traumatic thoracic aorta rupture: preclinical assessment, diagnosis and treatment options]

Traumatic aortic rupture is a life-threatening injury which is frequently associated with blunt thoracic trauma or found coincidentally in heavily traumatized patients. Depending on the degree of disruption of the damaged aortic wall, vascular injury is associated with a high primary mortality rate and a significant risk of secondary aortic rupture. Early clinical signs which may indicate a ruptured thoracic aorta are left sided thoracic pain, reduced ventilation, tachycardia and dyspnoe as well as hypotension in the lower extremities. The primary aim for emergency treatment is to maintain vital organ function and to hemodynamically stabilize the patient. Surgical treatment was previously performed by either direct aortic suture or segmental alloplastic graft interposition using the clamp and sew technique with or without extra-anatomic shunts or extracorporeal circulation. However, endovascular stent graft implantation has now become another treatment option for traumatic aortic rupture. According to the reported data and our own experience there is increasing evidence that endovascular aortic repair might become the treatment of choice for patients with traumatic aortic rupture, with the option of an early, less invasive intervention thus avoiding thoracotomy. Regular follow-up is necessary to detect possible stent graft migration or leakage which could require additional endovascular or open surgical re-interventions.

Spinal arterial anatomy and risk factors for lower extremity weakness following endovascular thoracoabdominal aortic aneurysm repair with branched stent-grafts

PURPOSE

To evaluate spinal arterial anatomy and identify risk factors for lower extremity weakness (LEW) following endovascular thoracoabdominal aortic aneurysm (TAAA) repair.

METHODS

A retrospective review was conducted of 37 patients (27 men; mean age 74.8+/-7.1 years, range 58-86) undergoing endovascular TAAA repair with branched stent-grafts at a single academic institution from July 2005 to December 2007. Data were collected on preoperative comorbidities, duration of operation, blood loss, type of anesthesia, extent of aortic coverage, blood pressure, cerebrospinal fluid (CSF) pressure and drainage, and postoperative development of LEW. Pre- and postoperative contrast-enhanced computed tomographic angiograms (CTA) in a 26-patient subset were analyzed to evaluate the number of patent intercostal and lumbar arteries before and after repair.

RESULTS

All patients were neurologically intact at the end of the operation. Seven (19%) patients developed LEW postoperatively: 6 perioperatively and 1 after discharge. LEW was associated with postoperative hypotension, internal iliac artery (IIA) occlusion, and fewer patent segmental arteries on preoperative CTA. Lowest mean systolic blood pressure was <90 mmHg in all 6 (100%) patients who developed LEW in hospital compared to 12 (44%) of the 27 patients who did not develop LEW (p = 0.02). Complete resolution of LEW (n = 4) followed prompt measures to raise blood pressure and lower CSF pressure. Persistent LEW (n = 3) was associated with sustained hypotension from sepsis, postoperative bleeding, and hemodialysis, respectively. Two (29%) of 7 patients with LEW either lost prograde flow to an IIA during repair or had bilaterally occluded IIAs preoperatively compared to 2 (7%) of 30 patients without LEW (p = 0.16). Comparison of pre- and postoperative CTAs showed no reduction in the mean number of patent segmental arteries in patients with or without LEW.

CONCLUSION

Endovascular TAAA repair inevitably occludes direct inflow to lumbar and intercostal arteries. The distal segments of these arteries to the spine, however, are seen to remain patent through collaterals. Measures to preserve collateral pathways and increase perfusion pressure may help prevent or treat LEW.