Early and mid-term results after endovascular repair of thoracoabdominal aortic aneurysms using the off-the-shelf multibranched t-Branch device: a national multi-center study

Objective: The multibranched off-the-shelf Zenith® t-Branch (Cook Medical, Bloomington, IN) device is commonly chosen for endovascular repair of thoracoabdominal aortic aneurysms. The aim of this study was to report early and mid-term outcomes in all patients treated with the t-Branch in Norway; Design and Methods: A retrospective multicenter study with Norwegian centers performing complex endovascular aortic repair was undertaken. T-Branch patients from 2014 to 2020 were included. All postoperative computed tomography angiography images were reviewed, and demographic, anatomical, perioperative and follow-up data were analyzed; Results: Seventy patients were treated in a single-step (n = 55) or staged (n = 15) procedure. Symptomatic presentation was seen in 20 patients, six of which had a contained rupture. Technical success was 87% (n = 59), with failures caused by unsuccessful bridging of target vessels (n = 4), target vessel bleeding (n = 3), persisting type 1c endoleak (n = 1) and t-Branch malrotation (n = 1). 30-day mortality was 9% (n = 6) and was associated with high BMI (p = .038). The spinal cord ischemia rate was 21% (n = 15) and was associated with type II aneurysms (OR 5.4, 95% CI 1.1-26.7, p = .04), smoking (OR 6.0, 95% CI 1.3-27.6, p = .02) and intraoperative blood loss (OR 1.1, 95% CI 1.0-1.3, p = .01). Survival at one, two and three years was 84 ± 4%, 70 ± 6% and 67 ± 6%, respectively. Freedom from aortic-related reinterventions at one, two and three years was 80 ± 5%, 65 ± 7% and 50 ± 8%, respectively; Conclusion: The study showed low early mortality (9%) and satisfactory mid-term survival. Technical success was achieved in acceptable 87% of procedures. The rate of spinal cord ischemia was high, occurring in 21% of patients.

SARS-CoV-2 and spinal cord ischemia: a systematic review on clinical presentations, diagnosis, treatment, and outcomes

BACKGROUND CONTEXT

Spinal cord ischemia is a rare but ominous clinical situation with high levels of disability. There are emerging reports on COVID-19 and spinal cord ischemic events.

PURPOSE

To investigate the cardinal manifestations of SARS-CoV-2 associated spinal cord ischemia, review treatment paradigms, and follow outcomes.

STUDY DESIGN

A systematic review.

METHODS

The current study was conducted under Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The authors searched PubMed, Scopus, Web of Science, and Google Scholar for studies published up to February 12, 2023, on spinal cord ischemia and SARS-CoV-2 infection. Data on patient demographics, study methods, medical records, interventions, and outcomes were extracted from eligible articles. For each data set, the authors performed pooled estimates examining 3 factors of interest, which were (1) predisposing factors (2) treatment regimens, and (3) neurological rehabilitation outcomes. Neurological status was reported as the American Spinal Injury Association (ASIA) impairment scale reported by data sets.

RESULTS

Six data sets were identified. The mean age of the study population was 50 years old, with 66.6% male predominance. Sixty-six percent of the patients had severe COVID-19. Five data sets reported preexisting coagulopathy. ASIA A and B were the most prevalent primary neurological status (80%). The mean interval between COVID-19 and the first neurological deficit was 13 days. Anterior spinal artery lesions were the most prevalent ischemic pattern. The most common treatment regimens were heparin and steroid therapy. Physical rehabilitation showed poor functional outcomes.

CONCLUSIONS

SARS-CoV-2 is associated with spinal cord ischemia through multiple neuropathological mechanisms. Proper coagulation profile control and aggressive rehabilitation may play a promising role in the prevention and recovery of spinal cord infarction in SARS-CoV-2 patients.

Transverse spinal cord infarction following immunoglobulin treatment in a patient with exfoliative dermatitis: A case report

RATIONALE

Transverse spinal cord infarction (SCI) is rare but highly disabling. Aortic thrombosis was described as one of the most common etiologies. Thromboembolic complications associated with intravenous immunoglobulin (IVIG) have been reported.

PATIENT CONCERNS

A previously well, 64-year-old man who was given the treatment of IVIG (0.4 g/kg/d for 5 days) for exfoliative dermatitis 2 weeks before, progressively developed flaccid paraplegia of lower extremities, loss of all sensations below T3 level and urinary incontinence within 50 minutes.

DIAGNOSES

A diagnosis of SCI and pulmonary embolism was made. IVIG was considered the possible cause.

INTERVENTIONS

Anticoagulation treatment and continuous rehabilitation were administered.

OUTCOMES

The neurologic deficiency of the patient was partially improved at the 3-year follow-up.

LESSONS

The rapid development of severe deficits within 4 hours mostly contributes to the diagnosis of SCI. Heightened awareness of possible thrombotic events is encouraged for a month-long period following IVIG therapy.

EGFR-Activated JAK2/STAT3 Pathway Confers Neuroprotection in Spinal Cord Ischemia-Reperfusion Injury: Evidence from High-Throughput Sequencing and Experimental Models

This study aimed to investigate the molecular mechanisms underlying spinal cord ischemia-reperfusion (SCI/R) injury. Through RNA-Seq high-throughput sequencing and bioinformatics analysis, we found that EGFR was downregulated in the spinal cord of SCI/R mice and may function via mediating the JAK2/STAT3 signaling pathway. In vitro cell experiments indicated that overexpression of EGFR activated the JAK2/STAT3 signaling pathway and reduced neuronal apoptosis levels. In vivo animal experiments further confirmed this conclusion, suggesting that EGFR inhibits SCI/R-induced neuronal apoptosis by activating the JAK2/STAT3 signaling pathway, thereby improving SCI/R-induced spinal cord injury in mice. This study revealed the molecular mechanisms of SCI/R injury and provided new therapeutic strategies for treating neuronal apoptosis.

Anesthetic Management of Middle Aortic Syndrome in an Adult: A Case Report

Middle aortic syndrome (MAS) is a rare disorder characterized by narrowing of the aorta. Depending on the location and extent of aortic narrowing, surgical management may be necessary to prevent long-term sequelae, such as stroke and congestive heart failure. We report a case of MAS and discuss the unique intraoperative anesthetic considerations including hemodynamic monitoring proximal and distal to the aortic narrowing, minimizing the risk of spinal cord ischemia, and utilization of intraoperative dobutamine stress testing to guide surgical management.

Association of Tarlov cyst with cauda equina syndrome and spinal cord infarction following caudal epidural block: A case report

RATIONALE

Caudal epidural block (CEB), which injects drugs into the epidural space through a sacral hiatus, is considered a safer alternative to other approaches. Serious complications, such as cauda equina syndrome or spinal cord infarction, have been reported very rarely, but their coexistence after CEB, which may be related to the ruptured perineural cyst, also known as a Tarlov cyst, was not reported.

PATIENT CONCERNS

A 40-year-old male patient presented with bilateral lower extremity radicular pain. CEB was performed without image guidance. The patient exhibited sensory deficits below L2, no motor function (0-grade), hypotonic deep tendon reflexes, and no pathological reflexes.

DIAGNOSES

Spinal cord infarction, cauda equina syndrome, and sacral level perineural cyst with hemorrhage.

INTERVENTION

High doses of steroids and rehabilitation were performed.

OUTCOMES

The patient was discharged after 28 days with persistent bilateral leg paralysis and sensory deficits below the L2 level. The patient demonstrated no neurological improvement.

LESSONS

Magnetic resonance imaging, including the sacral area, should be performed before performing CEB, to confirm the presence of a perineural cyst.

Thoracic endovascular aortic repair of metachronous thoracic aortic aneurysms following prior infrarenal abdominal aortic aneurysm repair

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) of metachronous thoracic aortic aneurysms (M-TAAs) following previous infrarenal abdominal aortic aneurysm (AAA) repair has been associated with higher spinal cord ischemia (SCI) risk compared with TEVAR of primary thoracic aortic aneurysms (TAAs). However, data on the impact of the type of prior infrarenal aortic repair on outcomes are scarce. In this study, we examined perioperative outcomes and long-term mortality following TEVAR M-TAA compared with primary TEVAR of TAA.

METHODS

We identified all Vascular Quality Initiative (VQI) patients who underwent TEVAR of TAA in the descending thoracic aorta from 2013 to 2022. Only patients undergoing primary TEVAR or TEVAR following infrarenal open (OAR) or endovascular (EVAR) repair were included. We performed univariate analyses to identify differences in baseline and procedural characteristics, and multivariable analyses for perioperative outcomes and 5-year mortality using logistic and Cox regression, respectively.

RESULTS

We included 1493 patients who underwent primary TEVAR (81%) or TEVAR following prior OAR (9.0%) or prior EVAR (9.7%). Compared with primary TEVAR, patients undergoing TEVAR M-TAA were older, more commonly male, white, and had higher rates of hypertension, smoking, and renal dysfunction. Patients with M-TAA were more likely to be asymptomatic and have larger diameters at presentation but were exposed to greater contrast volume and procedural times relative to primary TEVAR patients. Following risk-adjustment, compared with primary TEVAR, TEVAR after prior EVAR was associated with higher perioperative mortality (9.7% vs 3.9%; odds ratio [OR], 5.3; 95% confidence interval [CI], 2.3-12; P < .001) and 5-year mortality (40% vs 24%; hazard ratio [HR], 2.1; 95% CI, 1.4-3.1; P = .001). Specifically, among octogenarians (n = 375; 25%), the perioperative and 5-year mortality differences were even more pronounced (perioperative mortality: 17% vs 8.4%; OR, 6.7; 95% CI, 2.2-21; P = .001; 5-year mortality: 50% vs 27%; HR, 3.0; 95% CI, 1.5-5.7; P = .010). However, in-hospital complications, including SCI (2.6% vs 2.8%; OR, 1.2; 95% CI, 0.33-3.3; P = .77), were not notably different. In contrast, TEVAR after previous OAR was associated with comparable perioperative mortality (4.4% vs 3.9%; OR, 1.2; 95% CI, 0.32-3.8; P = .73), 5-year mortality (28% vs 24%; HR, 1.3; 95% CI, 0.80-2.1; P = .54), and in-hospital complications, including SCI (2.6% vs 0.7%; OR, 0.21; 95% CI, 0.01-1.1; P = .16).

CONCLUSIONS

Patients undergoing TEVAR of M-TAAs after prior EVAR, particularly octogenarians, have higher perioperative and 5-year mortality and therefore, represent a high-risk group. Future efforts should strive to discern the underlying factors leading to these poorer outcomes; meanwhile, these findings emphasize the need for careful patient selection and appropriate preoperative counseling in these high-risk individuals.

Outcomes following thoracic endovascular aortic repair for blunt thoracic aortic injury stratified by Society for Vascular Surgery grade

OBJECTIVES

Although the Society for Vascular Surgery (SVS) aortic injury grading system is used to depict the severity of injury in patients with blunt thoracic aortic injury, prior literature on its association with outcomes after thoracic endovascular aortic repair (TEVAR) is limited.

METHODS

We identified patients undergoing TEVAR for BTAI within the VQI between 2013 and 2022. We stratified patients based on their SVS aortic injury grade (grade 1, intimal tear; grade 2, intramural hematoma; grade 3, pseudoaneurysm; and grade 4, transection or extravasation). We assessed perioperative outcomes and 5-year mortality using multivariable logistic and Cox regression analyses. Secondarily, we assessed the proportional trends in patients undergoing TEVAR based on SVS aortic injury grade over time.

RESULTS

Overall, 1311 patients were included (grade1, 8%; grade 2, 19%; grade 3, 57%; grade 4, 17%). Baseline characteristics were similar, except for a higher prevalence of renal dysfunction, severe chest injury (Abbreviated Injury Score >3), and lower Glasgow Coma Scale with increasing aortic injury grade (Ptrend < .05). Rates of perioperative mortality by aortic injury grade were as follows: grade 1, 6.6%; grade 2, 4.9%; grade 3, 7.2%; and grade 4, 14% (Ptrend = .003) and 5-year mortality rates were 11% for grade 1, 10% for grade 2, 11% for grade 3, and 19% for grade 4 (P = .004). Patients with grade 1 injury had a high rate of spinal cord ischemia (2.8% vs grade 2, 0.40% vs grade 3, 0.40% vs grade 4, 2.7%; P = .008). After risk adjustment, there was no association between aortic injury grade and perioperative mortality (grade 4 vs grade 1, odds ratio, 1.3; 95% confidence interval, 0.50-3.5; P = .65), or 5-year mortality (grade 4 vs grade 1, hazard ratio, 1.1; 95% confidence interval, 0.52-2.30; P = .82). Although there was a trend for decrease in the proportion of patients undergoing TEVAR with a grade 2 BTAI (22% to 14%; Ptrend = .084), the proportion for grade 1 injury remained unchanged over time (6.0% to 5.1%; Ptrend = .69).

CONCLUSIONS

After TEVAR for BTAI, there was higher perioperative and 5-year mortality in patients with grade 4 BTAI. However, after risk adjustment, there was no association between SVS aortic injury grade and perioperative and 5-year mortality in patients undergoing TEVAR for BTAI. More than 5% of patients with BTAI who underwent TEVAR had a grade 1 injury, with a concerning rate of spinal cord ischemia potentially attributable to TEVAR, and this proportion did not decrease over time. Further efforts should focus on enabling careful selection of patients with BTAI who will experience more benefit than harm from operative repair and preventing the inadvertent use of TEVAR in low-grade injuries.

Spinal cord infarction resulting from intramural haematoma of the thoracic aorta

We present the case of a female patient in her 60s with multiple medical comorbidities who presented to the emergency department with sudden-onset tearing chest, back and abdominal pain in the setting of a hypertensive emergency. Initial CT-angiography demonstrated mild-diffuse thickening of thoracic and abdominal aorta without signs of intramural haematoma or dissection. The patient was subsequently admitted and medically managed. In the days following admission, the patient developed a small bowel obstruction and neurological deficits. Repeat imaging demonstrated an intramural haematoma extending from left subclavian artery to the diaphragm resulting in foci of spinal cord infarction. Instances of spinal cord infarction secondary to aortic intramural haematoma are rare, with a minority of cases reported as of 2020. This case report highlights a non-classic patient presentation of an intramural haematoma, shedding light onto possible clinical outcomes, treatment options and important risk factors.

Safety and Efficacy of Intentional Celiac Artery Coverage in Endovascular Management of Thoracoabdominal Aortic Diseases: A Systematic Review and Meta-analysis

PURPOSE

Thoracic endovascular aortic aneurysm repair (TEVAR) has emerged as an attractive alternative option in the treatment of thoracoabdominal aortic aneurysm (TAAA) diseases, reporting lower morbidity and mortality rates compared with open or hybrid repair. A challenging situation arises when the aneurysm involves the celiac artery (CA), precluding a safe distal landing zone. We investigated the safety and efficacy of CA coverage in the treatment of complex TAAA diseases during endovascular management.

MATERIALS AND METHODS

A review of the literature was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. The electronic bibliographic sources searched were MEDLINE and SCOPUS databases. Primary outcomes of interest were perioperative and 30-day mortality. Any type of endoleak, mesenteric ischemia, perioperative spinal cord ischemia, and reintervention rates were secondary end points. A random-effects meta-analysis was performed. Summary statistics of event risks were expressed as proportions and 95% confidence interval (CI).

RESULTS

Ten observational cohort studies published between 2009 and 2020, reporting a total of 175 patients, were eligible for quantitative synthesis. Indications for TEVAR were primary TAAAs in 82% of patients, aortic dissection in 14% of patients, type Ib endoleak after previous endograft deployment in 3% of patients, and penetrating aortic ulcer in 1 patient. Reintervention rate was 9% (95% CI, 4%-20%) and spinal cord ischemia was 7% (95% CI, 4%--12%). Type II endoleak was the predominant type of endoleak in 10% of patients (95% CI, 4%-22%), followed by type I endoleak in 5% of patients (95% CI, 2%-12%) and type III endoleak in 1% (95% CI, 0%-16%) of patients. Mesenteric ischemia occurred in 6% of patients (95% CI, 3%-10%). Thirty-day mortality was 5% (95% CI, 2%-13%) and the pooled estimate for overall mortality was 21% (95% CI, 14%-31%).

CONCLUSIONS

Celiac artery coverage during TEVAR is a challenging but feasible option for the treatment of TAAA diseases, providing acceptable morbidity and mortality rates. Demonstration of adequate visceral collateral pathways before definitive CA coverage is the sine quo non for the success of the technique.

Impact of high-risk features and timing of repair for acute type B aortic dissections

OBJECTIVE

The new Society for Vascular Surgery/Society for Thoracic Surgery reporting standards for type B aortic dissection (TBAD) categorize clinical presentations of aortic dissection into uncomplicated, high-risk features (HRF), and complicated groups. Although it is accepted that complicated dissections require immediate repair, the optimal timing of repair for HRF has yet to be established. This study aims to identify the ideal timing of thoracic endovascular aortic repair (TEVAR) for HRF, as well as outcomes associated with specific HRF.

METHODS

The Vascular Quality Initiative was queried for TEVARs performed for acute and subacute TBAD with HRF from 2014 to 2020. Rupture, malperfusion, and uncomplicated patients were excluded. HRF were defined per the guidelines as refractory hypertension, pain, or rapid expansion/aneurysm of more than 40 mm. The primary outcomes were in-hospital/30-day mortality and 1-year survival with primary exposure variables being days from symptoms to repair and number of HRFs. Secondary outcomes were spinal cord ischemia, stroke, and retrograde type A dissection (RTAD).

RESULTS

Of the 1100 patients who met inclusion criteria, 811 had one HRF, 249 had two, and 40 had three. There were no significant differences in primary or secondary outcomes based on number of HRFs. There were 309 patients who underwent repair at 0 to 2 days, 262 at 3 to 6 days, 270 at 7 to 14 days, and 259 at 15 days or more. TEVAR performed at 15 days or more was independently associated with lower in-hospital/30-day mortality (odds ratio, 0.38; P = .0388) and improved 1-year survival. Postoperative stroke was associated with earlier repair (0-2 days). There was no association of timing of repair with spinal cord ischemia, retrograde type A dissection or reintervention.

CONCLUSIONS

TEVAR for TBAD with HRF delayed at least 15 days from symptom onset is associated with improved survival, supporting the theory that it is best to delay TEVAR until the subacute phase. Additionally, TEVAR delayed at least 3 days is associated with a decrease in stroke. Having more than one HRF was not associated statistically with worse outcomes. Because the classification of HRF is relatively new and without guidelines for repair, this study highlights the risks of early intervention for HRF and suggests that these patients seem to benefit from at least a short stabilization period before TEVAR.

[Spinal Cord Infarction after Right Upper Lobectomy Combined with Chest Wall Resection]

A 42-year-old man presented with a one-month history of back pain. Chest computed tomography revealed a mass (7.6×5.7 cm) in the right upper lobe, suspicious of chest wall invasion. We performed right upper lobectomy combined with chest wall resection. Partial dissections of the second to sixth ribs and the third and fourth vertebral bodies were conducted. Postoperatively, motor paralysis of the right lower extremity was observed and a diagnosis of spinal infarction was made. After cerebrospinal fluid drainage and administration of edaravone with early rehabilitation, he was able to walk with a brace and was discharged from the hospital.

[Hybrid Treatment for Thoracoabdominal Aortic Aneurysm by Combined Graft Replacement and Stent-graft]

Graft replacement for thoracoabdominal aortic aneurysm(TAAA) is still an important technique, yet it has high risks of mortality, spinal cord ischemia, and pulmonary complications. In our hospital, thoracoabdominal aneurysm repair with grafting and endovascular treatment (TARGET) method was performed in patients with severe chronic obstructive pulmonary disease( COPD), severe pulmonary adhesions after descending aortic replacement, or those considered high risk from general condition to undergo a wide range replacement. In this method, thoracoabdominal aortic replacement near the diaphragm was followed by stent graft treatment of the residual proximal or distal lesions. Here the usefulness of this technique was reported.

[Preservation of the Spinal Perfusion Artery during Descending Thoracic and Thoracoabdominal Aortic Surgery]

This is a 3-case report of successful descending thoracic and thoracoabdominal aortic surgery by preserving the spinal perfusion artery (SPA) identified preoperatively. In Case 1, an 85-year-old woman, computed tomography (CT) showed Crawford type Ⅴ thoracoabdominal aortic aneurysm (TAAA:60 mm) and a SPA originated from L2. In Case 2, a 76-year-old man, CT revealed type Ⅳ TAAA( 58 mm) and a SPA originated from Th11. In Case 3, a 74-year-old man, CT detected an infectious pseudoaneurysm(44 mm) in the descending thoracic aorta with 2 SPAs originating from Th10 and L2. The ranges of graft replacement were Th7-Th12, Th12-L4, and Th8-Th10, respectively, while preserving all SPAs. All patients recovered well without postoperative neurological deficits. Although the protective effect of the SPA preservation against the spinal cord ischemia is still controversial, preoperative identification of the SPA was useful for planning a surgical strategy for descending thoracic and thoracoabdominal aortic repair surgery.

[Structural changes in the sensory ganglia of the spinal nerves after repeated magnetic stimulation on the model of ischemic myelopathy]

The aim of this study was to examine the association of morphological changes in the-sensory ganglia of the spinal nerves (SGSN) with the cilinical symptomatology in rats with the experimentally induced ischemic myelopathy (IM), untreated or treated with repeated magnetic stimulation (RMS). The efficacy and mechanisms of RMS action on SGSN were studied by electron microscopy in 16 rats with IM. According to the results of treatment, in SGSN both at a distance from the damaged area (lumbar SGSN) and close to it (cervical SGSN) the morphological signs of regenerative-reparative processes were found in the cells and nerve fibers (restoration of the organelle structure in the cytoplasm o0f neurons and neurolemmocytes, the increase in the number of he latter and fiber remyelination). The expression of the structural changes correlated with the degree of functional recovery.

Optimization of a mouse locomotor rating system to evaluate compression-induced spinal cord injury: correlation of locomotor and morphological injury indices

Object

Due to the usefulness of mouse genetics, there is a need to improve procedures for producing and assessing spinal cord injury (SCI) in mice. The authors describe an improved locomotor scoring system for evaluating SCI. The modified Basso-Beattie-Bresnahan (mBBB) scoring system for mice is compared with existing procedures as well as histological SCI criteria.

Methods

Mice were subjected to SCI by placing a weight on the cord at T-12 for 5 to 15 minutes after laminectomy to produce spinal cord ischemia. Injury was assessed using mBBB scoring that incorporates elements of the rat BBB and the mouse motor function scoring systems that are best suited for precisely assessing mouse SCI. The mBBB score was found to be more discriminating than the inclined plane test, and in the authors’ laboratory it had a significantly lower coefficient of variation than the Basso mouse scale score. The mBBB score is well correlated with sparing of white matter as assessed by eriochrome cyanine staining of myelin.

Conclusions

Weight placement at T-12 in the mouse causes reproducible SCI. A new mBBB scoring system is useful for accurately assessing locomotor dysfunction following SCI in mice and is well correlated with histological assessment of spinal cord white matter.

Successful repair of traumatic aortic tears using left heart bypass

Aortic tears commonly occur in multiply injured patients. Recognizing this injury is important. A chest X-ray is helpful and a CT-angiogram or aortogram confirmatory. After attending to life-threatening injuries, the aortic tear should be repaired immediately. Using the left heart bypass technique has the lowest risk of operative neurologic injury. We review our experience over the last 2 years, discuss our preferred technique and report on the outcome.

Spinal cord ischemia. Development of a model in the mouse

BACKGROUND AND PURPOSE

Spinal cord ischemia with resulting paraplegia is a devastating complication of thoracoabdominal aortic surgery. Experimental models of spinal cord ischemia have been developed in primate, dog, pig, rabbit, and rat with variable reproducibility, but none has been developed in mouse. Because genetically engineered mice have become important to examine the impact of specific genes in ischemic pathophysiology, we sought to develop a reproducible mouse model of spinal cord ischemia.

METHODS

C57BL/6NCrlBR mice were subjected to cross-clamping of the aortic arch, left subclavian artery, and internal mammary artery for 9 minutes (group A; n=8) or 11 minutes (group B; n=29) followed by reperfusion for 24 or 48 hours. Mean distal arterial blood pressure (left femoral artery) and lumbar (L1) spinal cord blood flow (laser-Doppler flowmetry) were measured for the duration of the procedure. The arterial blood supply of the spinal cord was visualized by intravascular perfusion of carbon black ink. We evaluated motor function in the hind limbs at 0, 1, 3, 6, and 24 hours after reperfusion using a rating scale of 0 (normal function) to 6 (total absence of movement). Spinal cord histopathology was evaluated after 24 and 48 hours of reperfusion by Luxol fast blue-hematoxylin and eosin.

RESULTS

The vascular anatomy of the mouse and human spinal cord appeared similar in that blood was supplied by 1 anterior and 2 posterior spinal arteries and heterosegmental radicular arteries. During combined occlusion of aortic arch and left subclavian artery, mean distal arterial blood pressure dropped to 10+/-5 mm Hg, and spinal cord blood flow at the L1 level decreased to 27+/-7% of baseline. All animals recovered from anesthesia with acute paraplegia. Animals in the 9-minute group (group A) showed steady recovery of hind limb function over the ensuing 24 hours, whereas the majority (80%) in the 11-minute group (group B) remained paralyzed with maximum deficit throughout the postoperative period. Mortality was 0% and 21% in groups A and B, respectively. Maximal ischemic damage was observed at the lower thoracic and higher lumbar spinal levels in both groups. In group A (9 minutes), tissue damage was mild, affecting predominantly dorsal horns and intermediate gray matter, whereas ventral horns were minimally involved. All mice in group B (11 minutes) showed extensive gray matter lesions particularly involving dorsal horns and intermediate areas; in ventral horns, >50% of motor neurons died. White matter lesions were present in the most severely damaged cords only.

CONCLUSIONS

Spinal cord ischemia caused by aortic arch plus left subclavian artery cross-clamping provides a mouse model useful for the study of spinal cord injury and of potential relevance to the complications following thoracoabdominal aortic surgery in humans.