Combined use of cerebral spinal fluid drainage and naloxone reduces the risk of paraplegia in thoracoabdominal aneurysm repair

Surgical treatment of a chronic thoracoabdominal dissection with false lumen thrombosis and true lumen compression determining multivisceral ischemia

INTRODUCTION

The treatment of a chronic type B aortic dissection can be challenging and need a precise and multidisciplinary planning.

MATERIALS AND RESULTS

A 62-year-old man presented to our hospital with acute aortic thrombosis on chronic thoracoabdominal dissection with bowel and kidney ischemia. He was submitted to urgent open surgical treatment with replacement of thoracoabdominal aorta and reimplantation of celiac trunk, superior mesenteric artery and right renal artery. During the intervention the visceral perfusion was provided with a modified Gott shunt; while the lower limb perfusion was provided by an existing right axillo-femoral and femoro-femoral bypass. The patient had a favorable course and did not report any complications.

CONCLUSION

The ideal management strategy of complex post-dissection conditions has to be tailored on the single patient's features to provide the maximal efficacy and safety. If the endovascular treatment is not viable, open surgery represents a valid option.

Impact of Intercostal Artery Reinsertion on Neurological Outcome after Thoracoabdominal Aortic Replacement: A 25-Year Single-Center Experience

BACKGROUND

Intercostal artery reinsertion (ICAR) during thoracoabdominal aortic replacement remains controversial. While some groups recommend the reinsertion of as many arteries as possible, others consider the sacrifice of multiple intercostals practicable. This study investigates the impact of intercostal artery reinsertion or sacrifice on neurological outcomes and long-term survival after thoracoabdominal aortic repair.

METHODS

A total of 349 consecutive patients undergoing thoracoabdominal aortic replacement at our institution between 1996 and 2021 were analyzed in a retrospective single-center study. ICAR was performed in 213 patients, while all intercostal arteries were ligated and sacrificed in the remaining cases. The neurological outcome was analyzed regarding temporary and permanent paraplegia or paraparesis.

RESULTS

No statistically significant differences were observed between the ICAR and non ICAR groups regarding the cumulative endpoint of transient and permanent spinal cord-related complications (12.2% vs. 11.8%, p = 0.9). Operation, bypass, and cross-clamp times were significantly longer in the ICAR group. Likewise, prolonged mechanical ventilation was more often necessary in the ICAR group (26.4% vs. 16.9%, p = 0.03). Overall long-term survival was similar in both groups in the Kaplan-Meier analysis.

CONCLUSION

Omitting ICAR during thoracoabdominal aortic replacement may reduce operation and cross-clamp times and thus minimize the duration of intraoperative spinal cord hypoperfusion.

Necrostatin-1 Attenuates Delayed Paraplegia after Transient Spinal Cord Ischemia in Rabbits by Inhibiting the Upregulation of Receptor-Interacting Protein Kinase 1 and 3

BACKGROUND

Delayed-onset paraplegia is a disastrous complication after thoracoabdominal aortic open surgery and thoracic endovascular aortic repair. Studies have revealed that transient spinal cord ischemia caused by temporary occlusion of the aorta induces delayed motor neuron death owing to apoptosis and necroptosis. Recently, necrostatin-1 (Nec-1), a necroptosis inhibitor, has been reported to reduce cerebral and myocardial infarction in rats or pigs. In this study, we investigated the efficacy of Nec-1 in delayed paraplegia after transient spinal cord ischemia in rabbits and assessed the expression of necroptosis- and apoptosis-related proteins in motor neurons.

METHODS

This study used rabbit transient spinal cord ischemia models using a balloon catheter. They were divided into a vehicle-treated group (n = 24), Nec-1-treated group (n = 24), and sham-controls (n = 6). In the Nec-1-treated group, 1 mg/kg of Nec-1 was intravascularly administered immediately before ischemia induction. Neurological function was assessed using the modified Tarlov score, and the spinal cord was removed 8 hr and 1, 2, and 7 days after reperfusion. Morphological changes were examined using hematoxylin and eosin staining. The expression levels of necroptosis-related proteins (receptor-interacting protein kinase [RIP] 1 and 3) and apoptosis-related proteins (Bax and caspase-8) were assessed using western blotting and histochemical analysis. We also performed double-fluorescence immunohistochemical studies of RIP1, RIP3, Bax, and caspase-8.

RESULTS

Neurological function significantly improved in the Nec-1-treated group compared with that in the vehicle-treated group 7 days after reperfusion (median 3 and 0, P = 0.025). Motor neurons observed 7 days after reperfusion were significantly decreased in both groups compared with the sham group (vehicle-treated, P < 0.001; Nec-1-treated, P < 0.001). However, significantly more motor neurons survived in the Nec-1-treated group than in the vehicle-treated group (P < 0.001). Western blot analysis revealed RIP1, RIP3, Bax, and caspase-8 upregulation 8 hr after reperfusion in the vehicle-treated group (RIP1, P = 0.001; RIP3, P = 0.045; Bax, P = 0.042; caspase-8, P = 0.047). In the Nec-1-treated group, the upregulation of RIP1 and RIP3 was not observed at any time point, whereas that of Bax and caspase-8 was observed 8 hr after reperfusion (Bax, P = 0.029; caspase-8, P = 0.021). Immunohistochemical study revealed the immunoreactivity of these proteins in motor neurons. Double-fluorescence immunohistochemistry revealed the induction of RIP1 and RIP3, and that of Bax and caspase-8, in the same motor neurons.

CONCLUSIONS

These data suggest that Nec-1 reduces delayed motor neuron death and attenuates delayed paraplegia after transient spinal cord ischemia in rabbits by selectively inhibiting necroptosis of motor neurons with minimal effect on their apoptosis.

Spinal drain-related complications after complex endovascular aortic repair using a prophylactic automated volume-directed drainage protocol

OBJECTIVE

A common measure to lower the risk for spinal cord ischemia (SCI) during complex endovascular aortic repair (cEVAR) is prophylactic cerebrospinal fluid drainage (CSFD). This method has caused controversy because of drain-related complications. Spinal drains are usually pressure directed. The objective of this study was to evaluate the risk of CSFD-related complications and SCI within the context of an automated volume-directed drain protocol.

METHODS

This is a retrospective, single-center study of all cEVARs with CSFD at a tertiary vascular center between January 2014 and December 2020. Demographics, complications, and spinal drain data were recorded. All drainages were volume based using an automatic drainage system (LiquoGuard7; Möller Medical GmbH). Spinal drain complications were categorized as disabling and nondisabling according to the modified Rankin scale. The primary end point was any CSFD-related complication.

RESULTS

A total of 448 cEVAR patients were identified, of whom 147 (32.8%) had prophylactic CSFD. The mean age was 69 years (63% male). The most common pathology (61%) was thoracoabdominal aortic aneurysm, and the most common procedure was branched EVAR (55.1%). Eighteen (12.2%) patients developed a CSFD-related complication, whereof three (2%) were disabling. Nineteen (13%) patients developed SCI: 12 (8.4%) paraparetic, 5 (3.4%) paraplegic, and 2 (1.4%) paresthesias. Of these, 13 (68%) had full reversal of symptoms, whereas 6 patients (4%) had residual symptoms and were deemed disabling. Drain-related complications were more common in patients with SCI (31.6%) compared with those without (9.4%, P = .014). In the latter group, only two patients (1.6%) developed a disabling drain-related complication.

CONCLUSIONS

Selective use of prophylactic, automated volume-directed CSFD in patients at high risk for SCI was associated with a high incidence of complications and should be used with caution. Among those developing SCI, reversal was achieved frequently with increased CSFD volume, but at the price of more bleeding complications.

Preoperative Spinal Drain Placement is Associated with Reduced Risk of Spinal Cord Ischemia in Patients Undergoing Thoracic Endovascular Aortic Repair for Aortic Dissection

BACKGROUND

Spinal cord ischemia (SCI) is a rare but serious complication of Thoracic Endovascular Aortic Repair (TEVAR). Several measures including spinal drain (SD) placement have been proposed to reduce the risk of SCI in TEVARs performed for aneurysms. However, there are no specific large-scale data on potential benefits of SD placement in Stanford Type B aortic dissection (TBAD). We aimed to assess the impact of preoperative SD placement on preventing SCI during TEVARs performed for TBAD.

METHODS

We included all TEVAR cases performed for TBAD in Vascular Quality Initiative (VQI) from 2012 to 2021. Patients with connective tissue disease, open conversion, rupture, proximal disease > zone 5, proximal landing zone <2 or SCI on presentation were excluded. One-to-one propensity score matching was used to balance patients on 34 dimensions by the nearest neighbor principle to compare patients based on preoperative SD placement. The primary outcome was SCI. Secondary outcomes included 30-day and 90-day mortality, perioperative complications, and 90-day2intervention.

RESULTS

A total of 2,683 TEVARs were performed for TBAD with 1,227 (45.7%) undergoing preoperative SD placement. Propensity matching produced 672 well-matched pairs. In the matched cohort, SD placement was not associated with significant reduction in temporary SCI (3.0% vs. 3.7%, P = 0.45). However, SD placement was associated with significant reduction of the risk of permanent SCI at discharge (1.3% vs. 3.4%, P = 0.012). SD was also associated with lower risk of 30-day mortality (3.7% vs 6.4%, P = 0.025) and shorter length of stay but not 90-day mortality or 90-day reintervention.

CONCLUSIONS

Our study suggests that preoperative SD placement in patients undergoing TEVAR for TBAD is beneficial in reducing the risk of permanent SCI without increasing risks of perioperative complications. Further prospective studies are necessary to confirm these findings.

Endoscopic-assisted descending aortic replacement through a small intercostal incision: a case report

BACKGROUND

Descending aortic replacement often involves making large incisions; thus, it results in massive invasions. We report the case of a patient with dilated descending aorta treated using endoscopic-assisted descending aortic replacement with essentially minimal invasions.

CASE PRESENTATION

We performed endoscopic-assisted descending aortic replacement with a single incision involving six wounds by trocar puncturing on a 59-year-old man who was diagnosed with dilated descending aorta by stent graft-induced new entry. Subsequently, the patient was discharged on postoperative day 11 without any complications.

CONCLUSIONS

Despite minor incisions, our approach can be indicated to almost the same group of patients in whom the conventional approach can be performed. Our procedure involved a single incision of only 8 cm and six wounds by trocar puncturing. Thus, endoscopic-assisted surgery can be a useful option in descending aortic surgery.

Prevention of Spinal Cord Injury during Thoracoabdominal Aortic Aneurysms Repair: What the Anaesthesiologist Should Know

Thoraco-abdominal aortic repair is a high-risk surgery for both mortality and morbidity. A major complication is paraplegia-paralysis due to spinal cord injury. Modern thoracic and abdominal aortic aneurysm repair techniques involve multiple strategies to reduce the risk of spinal cord ischemia during and after surgery. These include both surgical and anaesthesiologic approaches to optimize spinal cord perfusion by staging the procedure, guaranteeing perfusion of the distal aorta through various techniques (left atrium–left femoral artery by-pass) by pharmacological and monitoring interventions or by maximizing oxygen delivery and inducing spinal cord hypothermia. Lumbar CSF drainage alone or in combination with other techniques remains one of the most used and effective strategies. This narrative review overviews the current techniques to prevent or avoid spinal cord injury during thoracoabdominal aortic aneurysms repair.

Endovascular Repair of Descending Thoracic Aortic Aneurysms

Descending thoracic aortic aneurysms (DTAAs) are an important cause of morbidity and mortality in the elderly. Once diagnosed, they should be surveilled and then repaired at a diameter of 5.5 to 6 cm, depending on the individual patient's physiologic and anatomic risk of repair. Thoracic endovascular aortic repair (TEVAR) is the preferred approach for repair and there are multiple procedural adjuncts that can expand indications for and use of TEVAR. Spinal cord injuries are an important and highly morbid complication after TEVAR and it is imperative to mitigate this risk.

A Systematic Review of Spinal Cord Ischemia Prevention and Management After Open and Endovascular Aortic Repair

OBJECTIVE

Spinal cord ischemia (SCI) is one of the most devastating complications after descending thoracic aortic (DTA) and thoracoabdominal aortic (TAA) repairs. Patients who develop SCI have a poor prognosis with mortality rates reaching 75% within the first year after surgery. Many factors have been shown to increase the risk of this complication, including extent of TAA repair, length of aortic and collateral network coverage, embolization, and reduced spinal cord perfusion pressure. As a result, a variety of treatment strategies have evolved. We aimed to provide an up-to-date review of SCI rates with associated treatment algorithms from open and endovascular DTA and TAA repairs.

METHODS

Using PRISMA guidelines, a literature review with the Medical Subject Headings (MeSH) terms "spinal cord ischemia; spinal cord ischemia prevention and mitigation strategies; spinal cord ischemia rates; spinal cord infarction" was performed in the Cochrane and PubMed databases to seek all peer-reviewed studies of DTA and TAA repairs with SCI complications, limited to 2012-2021 and the English language. MeSH subheadings including diagnosis, complications, physiopathology, surgery, mortality, and therapy were used to further restrict the articles. Studies were excluded if they were not in humans, not pertaining to SCI in DTA/TAA operative repairs, and if the study primarily discussed neuromonitoring techniques. Additionally, studies with <40 patients or limited information regarding SCI protection strategies were excluded. Each study was individually reviewed by two researchers to assess for type and extent of aortic pathology, operative technique, SCI protection or mitigation strategies, rates of overall and permanent SCI symptoms, associations with SCI on multivariate analysis, and mortality.

RESULTS

Of 450 studies returned by the MeSH search strategy, 41 met inclusion criteria and were included in the final analysis. For endovascular DTA repair patients, overall SCI rates ranged from 0-10.6% with permanent SCI symptoms ranging from 0-5.1%. Endovascular and open TAA repairs had rates of overall SCI of 0-35%. Permanent SCI symptom rate was reported by only one open study at 1.1% while endovascular TAA repairs had between 2-20.5%.

CONCLUSION

This review provides an up-to-date review of current rates of SCI as well as prevention and mitigation strategies for DTA and TAA repairs. We find that a multimodal approach, including a bundled institutional protocol, staging of multiple repairs, preservation of collateral blood flow network, augmented spinal cord perfusion, selective cerebrospinal fluid drainage, and distal aortic perfusion in open TAA repairs, appears to be important in reducing the risk of SCI.

Hybrid repair versus conventional open repair for thoracic aortic arch aneurysms

BACKGROUND

Thoracic aortic arch aneurysms (TAAs) can be a life-threatening condition due to the potential risk of rupture. Treatment is recommended when the risk of rupture is greater than the risk of surgical complications. Depending on the cause, size and growth rate of the TAA, treatment may vary from close observation to emergency surgery. Aneurysms of the thoracic aorta can be managed by a number of surgical techniques. Open surgical repair (OSR) of aneurysms involves either partial or total replacement of the aorta, which is dependent on the extent of the diseased segment of the aorta. During OSR, the aneurysm is replaced with a synthetic graft. Hybrid repair (HR) involves a combination of open surgery with endovascular aortic stent graft placement. Hybrid repair requires varying degrees of invasiveness, depending on the number of supra-aortic branches that require debranching. The hybrid technique that combines supra-aortic vascular debranching with stent grafting of the aortic arch has been introduced as a therapeutic alternative. However, the short- and long-term outcomes of HR remain unclear, due to technical difficulties and complications as a result of the angulation of the aortic arch as well as handling of the arch during surgery.

OBJECTIVES

To assess the effectiveness and safety of HR versus conventional OSR for the treatment of TAAs.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 22 March 2021. We also searched references of relevant articles retrieved from the electronic search for additional citations.

SELECTION CRITERIA

We considered for inclusion in the review all published and unpublished randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing HR to OSR for TAAs.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all titles and abstracts obtained from the literature search to identify those that met the inclusion criteria. We retrieved the full text of studies deemed as potentially relevant by at least one review author. The same review authors screened the full-text articles independently for inclusion or exclusion.

MAIN RESULTS

No RCTs or CCTs met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

Due to the lack of RCTs or CCTs, we were unable to determine the safety and effectiveness of HR compared to OSR in people with TAAs, and we are unable to provide high-certainty evidence on the optimal surgical intervention for this cohort of patients. High-quality RCTs or CCTs are necessary, addressing the objective of this review.

Incidence of spinal cord ischemia according to the patency of reimplanted segmental arteries during thoracoabdominal aortic replacement

BACKGROUND

This study aimed to investigate the impact of segmental artery reimplantation and its patency on spinal cord ischemia (SCI) in thoracoabdominal aorta replacement.

METHODS

For 193 patients who underwent early postoperative computed tomographic (CT) angiography after thoracoabdominal aorta replacement, the technique of segmental artery reimplantation, their patency, and postoperative SCI were retrospectively investigated.

RESULTS

The early patency rate of reimplanted segmental artery was 83.3% (210 of 252), as 13 were taken down intraoperatively and 42 were not visualized in the postoperative CT angiography. The patency rate differed according to the reimplantation technique: 93.6% (131/140) for en bloc patch, 95.6% (43/45) for small individual patch, and 53.7% (36/67) for graft interposition. SCI occurred in 13 (6.3%) patients, 4 of whom (2.0%) remained paraplegic permanently. SCI was significantly more frequent (P=0.044) in the patients in whom segmental artery reimplantation was not successful (take-down or occlusion, 6/37=16.2%) than in those who had all segmental arteries sacrificed intentionally (2/64=3.1%) and those who showed patency of all reimplanted segmental arteries (5/92=5.4%). Especially, there was no permanent paraplegia in the last group. Failure of intended segmental artery reimplantation was a significant risk factor of postoperative SCI in logistic regression analysis (P=0.012; odds ratio 4.65, 95% confidence interval 1.41-15.36).

CONCLUSIONS

During thoracoabdominal aorta replacement, attention should be paid to the segmental artery reimplantation technique, which affects the risk of occlusion or intraoperative takedown and thereby may have impact on postoperative SCI.

Spinal cord protection in thoracoabdominal aortic aneurysm surgery: a multimodal approach

Spinal cord injury (SCI) is one major complication of open and endovascular thoracic and thoracoabdominal aortic aneurysm repair. Despite numerous neuroprotective adjuncts, the incidence of SCI remains high. This review article discusses established and novel adjuncts for spinal cord protection, including priming and preconditioning of the paraspinal collateral network, intraoperative systemic hypothermia, distal aortic perfusion, motor- and somatosensory evoked potentials and noninvasive cnNIRS monitoring as well as peri- and postoperative drainage of cerebrospinal fluid. Regardless of the positive influence of many of these strategies on neurologic outcome, to date no strategy assures definitive preservation of spinal cord integrity during and after aortic aneurysm repair.

Extrathoracic collaterals to critical segmental arteries after endovascular thoraco-abdominal aneurysm repair

OBJECTIVES

The risk of spinal cord injury after thoraco-abdominal aortic aneurysm repair increases when the segmental arteries (SAs) in the critical segment are sacrificed. Such critical SAs cannot be reconstructed when performing thoracic endovascular aortic repair (TEVAR). We aimed to elucidate extrathoracic collaterals to the critical SAs (T9-L1) that develop after TEVAR.

METHODS

Between 2006 and 2018, the critical SAs (T9-L1) of 38 patients were sacrificed during TEVAR. Nineteen of these patients who underwent multidetector row computed tomography 6 months after surgery were included (mean age 60 ± 13 years; 10 male; Crawford extent II:III, 14:5). We retrospectively assessed extrathoracic collaterals to the sacrificed critical SAs.

RESULTS

Ninety-four collaterals to the critical SAs were observed, originating from the subclavian (26/94), external iliac (50/94) and internal iliac (18/94) arteries. Twenty-five of the 26 (96%) collaterals from the subclavian artery were from its lateral descending branch, and 19 of the 26 (73%) collaterals fed into T9. Forty-three of the 50 (86%) collaterals from the external iliac artery were from its lateral ascending branch, and 25 of the 50 (50%) collaterals communicated with T11. Patients with a history of left thoracotomy (no collaterals in 6 patients) had fewer collaterals via the lateral descending branch of the left subclavian artery in comparison with the patients without (10 collaterals in 13 patients) (P = 0.009).

CONCLUSIONS

After critical SAs were sacrificed, extrathoracic collaterals developed with certain regularity. Previous left thoracotomy could influence the development of extrathoracic collaterals from the left subclavian artery.

Naloxone Continuous Infusion for Spinal Cord Protection in Endovascular Aortic Surgery Leads to Higher Opioid Administration and More Pain

OBJECTIVE

Compare total perioperative opioid use in patients receiving naloxone continuousinfusion (NCI) for spinal cord ischemia prophylaxis, versus patients not receiving NCI, in endovascular aortic repair.

DESIGN

Single-center, retrospective cohort review.

SETTING

Academic medical center.

PARTICIPANTS

Patients undergoing elective thoracic, thoracoabdominal, or abdominal aortic endovascular repair.

INTERVENTIONS

Patients were separated based on the use of naloxone continuous infusion as part of a spinal protection protocol. Primary endpoint was opioid requirements, in milligram morphine equivalents (MME), during the first 48 hours or during NCI. Secondary endpoints included: postoperative pain scores during the same interval; opioid requirements during hours 48 to 72; and pain scores during hours 48 to 72.

MEASUREMENTS AND MAIN RESULTS

Ninety-five procedures were included; 43 received naloxone continuous infusion and 52 patients were in the non-naloxone group. Opioid use from a linear mixed model was elevated across the entire continuum in the naloxone group (18 MMEs, 95% CI 13-24), with the greatest difference seen at the 24-to-48-hour interval (51 MMEs, 95% CI 26-75) after adjustment for age, incisions, and prehospital opioid use. In the naloxone group, pain score estimates were elevated at each postoperative interval of evaluation, with similar adjustment. Across the continuum this was 0.7 higher (95% CI 0.2-1.3); the zero-six-hour and six-to-12-hour intervals were 0.9 (95% CI 0.4-1.4) and 1.2 higher (95% CI 0.7-1.7).

CONCLUSIONS

Patients receiving anloxone continuous infusion to prevent spinal cord ischemia required greater quantities of opioids and had higher postoperative pain, compared with patients not requiring naloxone.

Association Between Motor-Evoked Potentials and Spinal Cord Damage Diagnosed With Magnetic Resonance Imaging After Thoracoabdominal and Descending Aortic Aneurysm Repair

OBJECTIVES

The authors investigated the association between intraoperative motor-evoked potential (MEP) changes and the severity of spinal cord infarction diagnosed with magnetic resonance imaging (MRI) to clarify the discrepancy between them, which was observed in patients with postoperative motor deficits after thoracic and thoracoabdominal aortic surgery.

DESIGN

A multicenter retrospective study.

SETTING

Motor-evoked potential <25% of control values was deemed positive for spinal cord ischemia. The severity of spinal cord infarction was categorized into grades A to D based on previous studies using the most severe axial MRI slices. The associations between MRI grade, MEP changes, and motor deficits were examined using logistic regression.

PARTICIPANTS

Twenty-three of 1,245 patients (from 1999 to 2013, at 12 hospitals in Japan) were extracted from medical records of patients who underwent thoracic and thoracoabdominal aortic repair, with intraoperative MEP examinations and postoperative spinal MRI.

INTERVENTIONS

No intervention (observational study).

MEASUREMENTS AND MAIN RESULTS

Motor-evoked potential <25% of control value was associated significantly with motor deficits at discharge (adjusted odds ratio [OR], 130.0; p = 0.041), but not with severity of spinal cord infarction (adjusted OR, 0.917; p = 0.931). Motor deficit at discharge was associated with severe spinal cord infarction (adjusted OR, 4.83; p = 0.043), MEP <25% (adjusted OR, 13.95; p = 0.031), and combined deficits (motor and sensory, motor and bowel or bladder, or sensory and bowel or bladder deficits; adjusted OR, 31.03; p = 0.072) in stepwise logistic regression analysis.

CONCLUSION

Motor-evoked potential <25% was associated significantly with motor deficits at discharge, but not with the severity of spinal cord infarction.

Cerebrospinal fluid drainage and thoracic endovascular aneurysm repair

Spinal cord complications including paraplegia and partial neurologic deficits remain a frequent problem during repair of descending thoracic or thoracoabdominal aortic aneurysms. Effective prevention of this dreaded complication is of paramount importance. Among the many adjuncts that have been proposed to prevent spinal cord complications, spinal fluid drainage is one that has been used by numerous teams. The aim of this review is to answer the following question: does spinal fluid drainage afford spinal cord protection during both open and endovascular repair of thoracic or thoracoabdominal aortic aneurysms?

Perioperative cerebrospinal fluid drainage for the prevention of spinal ischemia after endovascular aortic repair

Endovascular treatment of thoracic and thoracoabdominal aortic diseases is accompanied by a risk of spinal ischemia in 1-19% of patients, depending on the entity and extent of the disease. The use of perioperative drainage of cerebrospinal fluid is one of the invasive measures to reduce the occurrence of this severe complication. This article reviews the incidence of spinal ischemia, its risk factors, the evidence for carrying out cerebrospinal fluid drainage and its modern use by means of an automated, pressure controlled system (LiquoGuard®7).

Organ Protection During Thoracoabdominal Aortic Surgery: Rationale for a Multimodality Approach

Surgical repair of thoracoabdominal aortic aneurysms (TAAAs) remains a technically challenging operation that requires a systematic approach to prevent ischemic complications and achieve excellent clinical outcomes. Techniques for organ protection have evolved substantially over the past 20 years. This review describes our current multimodality approach to organ protection during TAAA repair.

Bypass Techniques for Descending Thoracic Aortic Surgery

The conduct of partial left heart bypass or partial car diopulmonary bypass (CPB) during surgery involving the descending thoracic aorta or thoracoabdominal aorta is one of the most unappreciated and misunder stood extracorporeal circulation procedures in cardio vascular surgery. It is different from conventional CPB, and although some uninitiated practitioners consider it simpler, it is in fact more complicated than conven tional CPB and involves different concepts. It requires expertise and skill in regulating the flow, pressure, and oxygenation of blood going to both the proximal and distal parts of the body and management of the special bypass or shunt procedures used, specialized monitor ing, and knowledge about the protection and preserva tion of organs both proximal and distal to the aortic clamping. It demands exquisite communication and un derstanding of the unique problems faced by the sur geon, anesthesiologist, and perfusionist.

Effect of Mesenteric Ischemia/Reperfusion on Spinal Cord Injury following Transient Aortic Occlusion in Rabbits

Purpose:

To investigate in a rabbit model if prolonged periods of mesenteric ischemia followed by reperfusion may affect the rate of neurological complications.

Methods:

An infrarenal aortic snare, which consisted of a Silastic vessel loop whose ends were passed through plastic tubing, was placed in 50 male New Zealand white rabbits. In 40 of these animals, a similar but smaller device was placed around the superior mesenteric artery (SMA); all devices were exteriorized to allow vessel occlusion in the awake animal. The aorta was occluded for 12 minutes in the 10 control and 40 experimental animals, but the experimental rabbits also had occlusion of the SMA for varying intervals: 10 minutes (group 1), 12 minutes (group 2), and 18 minutes (group 3). To assess the hemodynamic effects of aortic and aortic/SMA occlusion, select control and test animals had blood pressure and heart rate monitoring via indwelling carotid catheters during the occlusion periods. The animals were euthanized, and spinal cords from paralyzed and normal rabbits were examined histologically

Results:

Neurological deficit occurred in 20% of controls and in 70%, 80%, and 100% in the experimental groups, respectively. There were no significant differences in systemic blood pressure at any time point during occlusion and reperfusion in the monitored control or test animals. There was no evidence of thrombosis of spinal arteries on histological analysis, nor was there evidence of bowel infarction at the time of sacrifice in animals undergoing combined aortic/SMA occlusion.

Conclusions:

Mesenteric ischemia/reperfusion worsens the neurological outcome in animals undergoing transient aortic occlusion. This observation is independent of hemodynamic influences and not the result of spinal artery thrombosis.

Spinal Cord Blood Supply and Its Surgical Implications

The blood supply to the spine is based on a predictable segmental vascular structure at each spinal level, but true radiculomedullary arteries, which feed the dominant cord supply vessel, the anterior spinal artery, are relatively few and their locations variable. Under pathologic conditions, such as aortic stent grafting, spinal deformity surgery, or spinal tumor resection, sacrifice of a dominant radiculomedullary vessel may or may not lead to spinal cord ischemia, depending on dynamic autoregulatory or collateral mechanisms to compensate for its loss. Elucidation of the exact mechanisms for this compensation requires further study but will be aided by preoperative, intraoperative, and postoperative comparative angiography. Protocols in place at our center and others minimize the risk of spinal cord ischemia during planned radiculomedullary vessel sacrifice.

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.

Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery

BACKGROUND

During aortic aneurysm surgery, cross-clamping can lead to inadequate blood supply to the spinal cord resulting in neurological deficit. Cerebrospinal fluid drainage (CSFD) may increase the perfusion pressure to the spinal cord and hence reduce the risk of ischaemic spinal cord injury.

OBJECTIVES

To determine the effect of CSFD during thoracic and thoracoabdominal aortic aneurysm (TAAA) surgery on the risk of developing spinal cord injury.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 31 2012) and CENTRAL (2012, Issue 5) for publications describing randomised controlled trials of cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery. Reference lists of relevant articles were checked.

SELECTION CRITERIA

Randomised trials involving CSFD during thoracic and TAAA surgery.

DATA COLLECTION AND ANALYSIS

Both authors assessed the quality of trials independently. SNK extracted data and GS verified the data.

MAIN RESULTS

Three trials with a total of 287 participants operated on for Type I or II TAAA were included.In the first trial of 98 participants, neurological deficits in the lower extremities occurred in 14 (30%) of CSFD group and 17 (33%) controls. The deficit was observed within 24 hours of the operation in 21 (68%), and from three to 22 days in 10 (32%) participants. CSFD did not have a significant benefit in preventing ischaemic injury to the spinal cord.The second trial of 33 participants used a combination of CSFD and intrathecal papaverine. It showed a statistically significant reduction in the rate of postoperative neurological deficit (P = 0.039), compared to controls. Analysis was undertaken after only one third of the estimated sample size had entered the trial.In the third trial TAAA repair was performed on 145 participants. CSFD was initiated during the operation and continued for 48 hours after surgery. Paraplegia or paraparesis occurred in 9 of 74 participants (12.2%) in the control group versus 2 of 82 participants (2.7%) receiving CSFD (P = 0.03). Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. Meta-analysis showed an odds ratio (OR) of 0.48 (95 % confidence interval (CI) 0.25 to 0.92). For CSFD-only trials, OR was 0.57 (95% CI 0.28 to 1.17) and for intention-to-treat analysis in CSFD-only studies, the OR remained unchanged.

AUTHORS' CONCLUSIONS

There are limited data supporting the role of CSFD in thoracic and thoracoabdominal aneurysm surgery for prevention of neurological injury. Further clinical and experimental studies are indicated.

Role of induced hypothermia in thoracoabdominal aortic aneurysm surgery

For more than 50 years, hypothermia has been used in aortic surgery as a tool for neuroprotection. Hypothermia has been introduced into thoracoabdominal aortic aneurysm (TAAA) surgery by many cardiovascular centers to protect the body's organs, including the spinal cord. Numerous publications have shown that hypothermia can prevent immediate and delayed motor dysfunction after aortic cross-clamping. Here, we reviewed the historical application of hypothermia in aortic surgery, role of hypothermia in preclinical studies, cellular and molecular mechanisms by which hypothermia confers neuroprotection, and the role of systemic and regional hypothermia in clinical protocols to reduce and/or eliminate the devastating consequences of ischemic spinal cord injury after TAAA repair.

Neurological complications of thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) has decreased the morbidity and mortality associated with open surgical repair of descending thoracic aortic diseases, but important complications unique to the procedure remain. Spinal cord ischemia and infarction is a recognized complication caused by endovascular coverage or injury to spinal cord collateral vessels. Stroke is a consequence of thromboembolism or coverage of aortic arch branch vessels with insufficient collateral circulation. Understanding the risk factors and the pathophysiology of neurological complications of TEVAR are important for the successful anesthetic and surgical management and treatment of patients undergoing endovascular procedures involving the thoracic aorta.

The effect of adrenergic β(2) receptor agonist on paraplegia following clamping of abdominal aorta

INTRODUCTION

Surgical repair of an aortic aneurysm might be complicated by spinal cord injury and paraplegia. Since β-adrenoreceptor agonists showed neuroprotective effects, the study was designed to investigate the effect of clenbuterol on post-aortic clamping paraplegia and to identify if there is hyperemia associated with paraplegia.

MATERIAL AND METHODS

Thirty rabbits were divided into two groups: 15 control and 15 experimental (given clenbuterol 9 mg in drinking water 24 h prior to surgery). All the animals were subjected to laparotomy whereas the abdominal aorta was identified. Using a vascular clamp, the abdominal aorta was clamped just distal to the renal arteries. Abdominal aortic blood flow was recorded with a transonic flow meter. The neurological assessment was made according to Tarlov's Neurological Scale upon recovering from anesthesia. Anal sphincter tonus and bladder sphincter function were also checked.

RESULTS

Four rabbits (2 control and 2 experimental) developed complete paraplegia within 30 min of cross-clamping of the aorta. Of the 13 controls, 77% developed paraplegia, and of the 13 experimental rabbits administered clenbuterol 24 h prior to surgery with 22 min of aortic cross-clamping, 38% developed paraplegia The rabbits which did not develop paraplegia had a minimal increase in aortic blood flow, whereas the rabbits which developed paraplegia had a significant increase in aortic blood flow measurements after aortic decamping.

CONCLUSIONS

Post-aortic clamping paraplegia is associated with hyperemia and clenbuterol has a significant neuroprotective effect, obviously by preventing an increase in aortic blood flow following unclamping.

Thoracic aortic aneurysms and dissections: endovascular treatment

The treatment of thoracic aortic disease has changed radically with the advances made in endovascular therapy since the concept of thoracic endovascular aortic repair was first described 15 years ago. Currently, there is a diverse array of endografts that are commercially available to treat the thoracic aorta. Multiple studies, including industry-sponsored and single-institution reports, have demonstrated excellent outcomes of thoracic endovascular aortic repair for the treatment of thoracic aortic aneurysms, with less reported perioperative morbidity and mortality in comparison with conventional open repair. Additionally, similar outcomes have been demonstrated for the treatment of type B dissections. However, the technology remains relatively novel, and larger studies with longer term outcomes are necessary to more fully evaluate the role of endovascular therapy for the treatment of thoracic aortic disease. This review examines the currently available thoracic endografts, preoperative planning for thoracic endovascular aortic repair, and outcomes of thoracic endovascular aortic repair for the treatment of both thoracic aortic aneurysms and type B aortic dissections. Mt Sinai J Med 77:256-269, 2010. (c) 2010 Mount Sinai School of Medicine.

A case of effective cerebrospinal fluid drainage for paraplegia caused by acute aortic dissection

A 65-year-old man with sudden back pain was transferred to our hospital by ambulance, who also complained of sensory and motor disorder of bilateral legs on arrival. The neurological disorder was gradually aggravated and paraplegia below the level of Th10 was manifested. Computed tomography demonstrated DeBakey IIIb acute aortic dissection; therefore, the paraplegia was thought to be due to spinal cord ischemia caused by the acute aortic dissection. Emergent cerebrospinal fluid drainage was performed, and it was very effective for the relief from paraplegia. The hospital course after the drainage was uneventful and he was discharged on the 39th day after the onset of symptoms.

A staged total aortic replacement with combined endovascular and open surgery: report of a case

For a 75 year-old man with extensive aortic aneurysm, who had undergone a previous infra-renal abdominal Y-graft, a staged replacement of remaining segments was performed. A hybrid procedure of open-laparotomy debranching of visceral branches and endovascular stentgraft insertion in the thoracoabdominal aorta was performed first, followed by subsequent direct replacement between the proximal ascending and distal arch using cardiopulmonary bypass. Three months thereafter dissection of enlarged proximal descending aorta occurred, for which we performed an emergent endovascular stentgraft deployment which bridged "elephant trunk" of the arch graft and the previous stentgraft. Consequently total aortic replacement was successfully accomplished without any neurological sequela.