Vascular Surgery Practice Guidelines during COVID-19 Pandemic in a Setting of High Work Volume Against Limited Resources: Perspective of a Developing Country.

BACKGROUND: The situation of coronavirus disease 2019 (COVID-19) pandemic in the Indian subcontinent is worsening. In Bangladesh, rate of new infection has been on the rise despite limited testing facility. Constraint of resources in the health care sector makes the fight against COVID-19 more challenging for a developing country like Bangladesh. Vascular surgeons find themselves in a precarious situation while delivering professional services during this crisis. With the limited number of dedicated vascular surgeons in Bangladesh, it is important to safeguard these professionals without compromising emergency vascular care services in the long term. To this end, we at the National Institute of Cardiovascular Diseases and Hospital, Dhaka, have developed a working guideline for our vascular surgeons to follow during the COVID-19 pandemic. The guideline takes into account high vascular work volume against limited resources in the country. METHODS: A total of 307 emergency vascular patients were dealt with in the first 4 COVID-19 months (March through June 2020) according to the working guideline, and the results were compared with the 4 pre-COVID-19 months. Vascular trauma, dialysis access complications, and chronic limb-threatening ischemia formed the main bulk of the patient population. Vascular health care workers were regularly screened for COVID-19 infection. RESULTS: There was a 38% decrease in the number of patients in the COVID-19 period. Treatment outcome in COVID-19 months were comparable with that in the pre-COVID-19 months except that limb loss in the chronic limb-threatening ischemia patients was higher. COVID-19 infection among the vascular health care professionals was low. CONCLUSIONS: Vascular surgery practice guidelines customized for the high work volume and limited resources of the National Institute of Cardiovascular Diseases and Hospital, Dhaka were effective in delivering emergency care during COVID-19 pandemic, ensuring safety of the caregivers. Despite the fact that similar guidelines exist in different parts of the world, we believe that the present one is still relevant on the premises of a deepening COVID-19 crisis in a developing country like Bangladesh.

Surgical treatment for isolated coarctation of the aorta in an adult patient.

A 51-year-old woman developed heart failure due to severe hypertension of the upper half of the body caused by coarctation of the aorta. From the available surgical options for this condition, we selected bypass grafting from the left subclavian artery to the descending aorta for this patient.

Interleukin-1 receptor antagonist attenuates the severity of spinal cord ischemic injury in rabbits.

OBJECTIVE: Thoracic and thoracoabdominal aortic surgery is sometimes complicated by subacute or delayed paraplegia. Pro-inflammatory cytokine interleukin-1 (IL-1) beta has been implicated in extensive inflammation and progressive neurodegeneration after ischemia. Using a rabbit model, we investigated the neuroprotective effects of IL-1 receptor antagonist (IL-1ra) in a temporal fashion. METHODS: Spinal cord ischemia was induced by aortic cross-clamping in New Zealand White rabbits. The animals were assigned to three groups. Group C (n = 20) received saline (0.2-mL) and Group I (n = 20) received IL-1ra (200-microg/0.2-mL) intrathecally just after reperfusion. Group S (n = 3) underwent sham operation without aortic occlusion. We assessed the neuroprotective effects of IL-1ra by evaluating neurological function, histopathological changes, and in-situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL staining). We also measured the levels of Nitric Oxide (NO) and S100beta in cerebrospinal fluid (CSF). Each evaluation was performed sequentially within 120 hours after reperfusion. RESULTS: Group C showed progressive deterioration of motor function which became statistically significant from 48 hours after the onset of reperfusion (P < .05, P < .01, P < .001, P < .001 at 48, 72, 96, and 120 hours, respectively). Compared to Group C, a higher number of viable neurons was observed with less severe spinal cord injury in Group I (P < .01, .05 and .05 at 24, 72, and 120 hours, respectively). TUNEL-positive neurons were also significantly reduced by the administration of IL-1ra (P <.01 and .05 at 24, and 120 hours, respectively). The difference between Group C and Group I with regard to NO was significant at 72 and 120 hours (P < .05), while that in terms of S100beta was significant only at 24 hours (P < .05). CONCLUSIONS: Administration of IL-1ra attenuates spinal cord ischemic-reperfusion injury as evidenced by reducing both neuronal necrosis and apoptosis.

Changes in cerebrospinal fluid and blood lactate concentrations after stent-graft implantation at critical aortic segment: a preliminary study.

OBJECTIVES: Obstruction of blood flow through the arteria radicularis magna (ARM) has been linked with ischemic spinal cord injury after conventional thoracic aortic repair. Whether or not endoluminal stent-grafts, deliberately positioned against this artery can cause similar damage to the spinal cord has not been comprehensively investigated. The purpose of this study was to assess the blood and cerebrospinal fluid (CSF) concentrations of lactate - a well-known biochemical marker of ischemic neurological injury, before and after stent-graft implantation against the ARM. MATERIALS AND METHODS: Endoluminal stent-grafting was performed in ten mongrel dogs. In five animals (experimental group), stent-grafts covered the fourth and fifth lumbar segmental arteries - which have been described as the canine equivalents to the ARM in humans. In the remaining five animals (control group), devices of similar length were placed in the lower thoracic aorta. CSF was obtained by cisternal puncture technique at the following time points; before stent-grafting, and 15, 30 and 60 min after stent-grafting. Parallel arterial blood samples were also obtained using a heparinized syringe. All samples were centrifuged and the supernatant analysed for lactate. RESULTS: The mean preprocedural lactate concentration in the CSF was 1.7+/-0.3 mmol/l. Mean postprocedural levels in the experimental group at 15, 30 and 60 min were 3.1+/-1.9, 3.9+/-1.1 and 11.9+/-2.5 mmol/l, respectively (control values; 2.1+/-1.9, 2.7+/-1.1 and 1.9+/-1.5 mmol/l, respectively). Mean preprocedural blood lactate level was 1.8+/-0.6 mmol/l, while the mean postprocedural concentrations in the experimental group at 15, 30 and 60 min were 2.9+/-1.2, 3.4+/-1.7 and 3.9+/-2.0 mmol/l, respectively. Two out of the five animals in the experimental group suffered mild to moderate hind limb weakness. CONCLUSION: Selective placement of stent-grafts against the ARM in dogs resulted in a conspicuous increase in CSF and blood lactate concentrations 60 min after the procedure with or without physical signs of neurological deficits. Although the small sample size of this preliminary study does not allow any definitive conclusion, it may be worthwhile to confirm the findings in appropriately controlled larger studies.

Readministration of gefitinib in a responder after treatment discontinuation due to gefinitib-related interstitial lung disease: a case report.

INTRODUCTION: Gefitinib is a new molecular-targeted agent for the treatment of patients with advanced non-small cell lung cancer that fail to respond to conventional chemotherapy. Gefitinib is considered to be well tolerated and less toxic compared with conventional cytotoxic drugs. However, interstitial lung disease (ILD) has been reported as a serious adverse effect. The precise management of a gefitinib responder having severe adverse events remains unknown. CASE PRESENTATION: We report the case of gefitinib readministration in a patient with lung adenocarcinoma who had once responded but in whom treatment had to be discontinued owing to gefinitib-related ILD. A dramatic response was achieved both at the time of initial treatment (250 mg/day) and at readministration of gefitinib (125 mg/day). The effectiveness of gefitinib therapy in our patient could be explained in part by the presence of an activating mutation of epidermal growth factor receptor (EGFR) gene, L858R in exon 21, which was identified in the primary tumor. CONCLUSION: A reduced dose of gefitinib might be sufficient for patients having tumors with EGFR gene mutations, and that the currently approved dose may be excessively potent in some of these patients, thus resulting in the onset of adverse events.

Surgical resection after gefitinib treatment in patients with lung adenocarcinoma harboring epidermal growth factor receptor gene mutation.

Gefitinib is the first approved epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) for the treatment of patients with advanced non-small cell lung cancer (NSCLC) who failed to respond to conventional chemotherapy. Gefitinib has fairly effective anti-tumour activity in patients with tumours harboring EGFR gene mutations. However, there has been no data about the preoperative gefitinib treatment in NSCLC patients. We reported here two cases of surgical resection of residual disease after dramatic response to gefitinib in patients with lung adenocarcinoma harboring EGFR gene mutation. Because both of our patients initially had advanced local tumour burden (bulky N2 disease), complete resection would not have been technically feasible. However, preoperative gefitinib treatment made it possible to achieve complete resection in both patients. We believe that clinical trials are required to evaluate the role of preoperative treatment of EGFR-TKIs in patients with locally advanced NSCLC harboring EGFR gene mutation.

How do we manage the gastrectomy for gastric cancer after coronary artery bypass grafting using the right gastroepiploic artery? Report of two cases and a review of the literature.

BACKGROUND: Recently, the right gastroepiploic artery (RGEA) has been used in coronary artery bypass grafting (CABG) as an alternative arterial graft. Unfortunately, an increased incidence of gastric cancers has been reported after CABG using the RGEA. Handling of the RGEA during gastrectomy in these patients may cause lethal complications, which sometimes reduces the feasibility of curative dissection of lymph nodes at the base of the graft. CASE PRESENTATIONS: We describe two cases of gastric cancer undergoing gastrectomy after CABG with the use of RGEA. To avoid the potentially fatal coronary event during gastrectomy, safe handling of the conduit including preparations for injuries and prevention of vessel spasm was performed in both cases, accompanied by an adequate monitoring of the systemic circulation. Intraoperative frozen section examination showed no lymph node metastasis around the graft in any of the cases; therefore, complete lymph node dissection at the base of the graft was not undertaken. No complications occurred during the operation. In addition to these two cases, twenty-four cases reported in the literatures were reviewed (a total of 26 cases). Ten early and 16 advanced gastric cancers were included. Among the 16 advanced gastric cancer cases, an alternative graft was employed in 8 due to the resection of an original graft to complete lymph node dissection. Mere handling of a graft often caused lethal complications suggesting that the operation should be completed by isolation of the graft. A pedicled graft harvesting via the ante-gastric route was popular. However, a skeletonized harvesting with resection of the pyloric branches of the RGEA would be better because this would interrupt the original lymph flow, which could eliminate the need for lymph node dissection and graft isolation. Among the 10 cases having early gastric cancers, 6 were found within 1.5 years after CABG. Early detection in these 6 cases was possible due to the use of gastric fiberscopic examination before and after CABG, which gave them opportunities to receive a less extensive operation such as endoscopic mucosal resection. CONCLUSION: Adequate intraoperative care as well as an optimal lymph node dissection considering the graft harvesting method at the first CABG leads to successful gastrectomy after CABG using the RGEA graft. Therefore, this operation should be carried out with careful management by both gastrointestinal and cardiovascular surgeons.

Therapeutic benefit of intrathecal injection of marrow stromal cells on ischemia-injured spinal cord.

BACKGROUND: Prophylactic transplantation of marrow stromal cells (MSCs) before spinal cord ischemia has been shown to attenuate neurologic injures. We sought to investigate the therapeutic effect of MSCs on ischemia-injured spinal cord. METHODS: Marrow stromal cells were expanded in vitro and prelabeled with bromodeoxyuridine. Spinal cord ischemia was induced in rabbits by infrarenal aortic occlusion for 30 minutes. Four groups were enrolled. About 1 x 10(8) MSCs were intrathecally injected 2 hours (group MSC-2h), 24 hours (group MSC-24h), or 48 hours (group MSC-48h) after spinal cord ischemia, respectively. The control group received intrathecal injection of medium alone. Hind-limb motor function was assessed during a 28-day recovery period with Tarlov criteria, and then histologic examination was performed. RESULTS: Marrow stromal cells still could be found in the spinal cord 4 weeks after transplantation. The capillary density in the ventral gray matter was significantly increased in the three MSC-treated groups (p < 0.01 versus control group, respectively). After a 28-day recovery, marked functional improvement was detected in group MSC-2h (from day 1 to 28, p < 0.05, versus control group, respectively) and group MSC-24h (from day 14 to 28, p < 0.05, versus control group, respectively), but not in group MSC-48h. The number of intact motor neurons was much greater in group MSC-2h (p < 0.05, versus control group). CONCLUSIONS: Intrathecal injection of MSCs enhances angiogenesis in the host spinal cord and improves the motor functional recovery after spinal cord ischemia. The therapeutic time window is critical for the therapeutic effect of MSCs.

Controlled low-pressure perfusion at the beginning of reperfusion attenuates neurologic injury after spinal cord ischemia.

OBJECTIVE: Paraplegia caused by spinal cord ischemia remains a serious complication after surgical repair of thoracoabdominal aortic aneurysms. This study tests the hypothesis that controlled low-pressure perfusion at the beginning of reperfusion can attenuate neurologic injury of the spinal cord after transient ischemia. METHODS: Spinal cord ischemia was accomplished in rabbits by occlusion of the infrarenal aorta with a balloon catheter for 25 minutes. In the normal reperfusion group, reperfusion was completely restored immediately after ischemia, whereas perfusion pressure was controlled between 45 and 55 mm Hg during the first 10 minutes followed by complete reperfusion in the low-pressure reperfusion group. Functional evaluation with the Tarlov score during a 14-day observation period, histopathologic assessment of the lumbar spinal cord, and measurements of malondialdehyde levels and amyloid precursor protein immunoreactivity were performed. RESULTS: Neurologic impairment was remarkably attenuated in the low-pressure reperfusion group (compared with the Tarlov scores of the normal reperfusion group, P < .05 at day 2; P < .01 at days 1, 7, and 14). Compared with the normal reperfusion group, malondialdehyde levels were significantly lower in the low-pressure reperfusion group (P < .05), and the large motor neurons of the low-pressure reperfusion group were preserved to a much greater extent (P < .05). White matter injury of the low-pressure reperfusion group was also markedly attenuated as evidenced by reduction of vacuolation area of the white matter (P < .05) and decrease of the amyloid precursor protein immunoreactivity (P < .05). CONCLUSION: Reperfusion initiated with low-pressure perfusion exerts neuroprotective effects on the spinal cord against ischemia/reperfusion injury.

Effect of prophylactically administered edaravone during antegrade cerebral perfusion in a canine model of old cerebral infarction.

OBJECTIVE: Reactive free radical species are thought to be involved in postoperative neurologic dysfunction after antegrade selective cerebral perfusion in brains with old infarction. We assessed the brain protective effect of prophylactically administered edaravone, a free radical scavenger, for antegrade selective cerebral perfusion in brains with or without old infarction in a canine model. METHODS: A canine model of old cerebral infarction was created by injecting cylindric silicone embolus into the middle cerebral artery. Animals showing obvious neurologic deficits and surviving 4 weeks or longer were included in the model. Deep hypothermia with antegrade selective cerebral perfusion was performed in both intact (non-edaravone, group A; edaravone-treated, group B) and infarcted animals (non-edaravone, group C; edaravone-treated, group D). Serum concentrations of malondialdehyde, hexanoyl-lysine, glutamate, and venous-arterial lactate difference were measured, and central conduction time and amplitude of somatosensory evoked potentials were assessed during the operation. RESULTS: Compared with the intact groups, serum concentrations of malondialdehyde and hexanoyl-lysine in group C significantly increased at the end of antegrade selective cerebral perfusion, whereas that of glutamate did so in the rewarming phase. Increases in all these biochemical parameters were suppressed in group D. In group C, the venous-arterial lactate difference was significantly greater in the rewarming phase at 28 degrees C compared with intact groups. A significant prolongation of postoperative central conduction time and decrease in neuronal activity were detected in group C, both of which recovered in group D. CONCLUSION: Prophylactic administration of edaravone exerted a significant protective effect against postoperative neurologic dysfunction after antegrade selective cerebral perfusion in a canine model with old cerebral infarction.

Aortic arch replacement using selective cerebral perfusion.

BACKGROUND: The present study was conducted to report our clinical experience with aortic arch replacement using selective cerebral perfusion (SCP) and determine the independent predictors of in-hospital mortality and neurologic outcome. METHODS: We studied 472 consecutive patients who underwent aortic arch replacement using SCP between January 1986 and February 2006. All operations were performed with the aid of hypothermic extracorporeal circulation, SCP, and in most cases, systemic circulatory arrest for open distal anastomosis. The etiology of aortic diseases included acute aortic dissection in 126 patients (27%), chronic aortic dissection in 102 (21%), and degenerative aneurysm in 245 (52%). Total arch replacement was performed in 420 patients (89%). Mean SCP time was 88 +/- 32 minutes. RESULTS: The overall in-hospital mortality was 9.3%, but it dropped significantly to 4.1% in the most recent 266 patients. Independent predictors of in-hospital mortality were early series, renal/mesenteric ischemia, pump time, increasing age, chronic renal dysfunction, history of cerebrovascular accident (CVA), and previous ascending or arch operation. Overall postoperative temporary and permanent neurologic dysfunction were 4.7% and 3.2%, respectively. A history of CVA was the only predictor of temporary neurologic dysfunction, whereas CVA and pump time were independent predictors of permanent neurologic dysfunction. SCP time had no significant correlation with in-hospital mortality and neurologic outcome. CONCLUSIONS: SCP facilitates complicated aortic arch replacement, resulting in a reduction of mortality and morbidity for arch aneurysms or dissections.

Aorto-right atrial fistula following acute type A aortic dissection repair.

This report describes a rare case of aorto-right atrial fistula caused by rupture of a huge pseudoaneurysm that developed at the proximal aortic anastomotic site after total aortic arch replacement for acute type A aortic dissection. Preoperative aortography revealed that the fistula communicated with the right heart, but it was intraoperative Doppler transesophageal echocardiography that confirmed its course into the right atrium. Repeat total aortic arch replacement with concomitant direct closure of the fistula was performed successfully. The underlying cause of the pseudoaneurysm was the dehiscence of sutures at the proximal aortic anastomotic site, probably due to gelatin-resorcin-formaldehyde glue.

Nonviral gene transfer of hepatocyte growth factor attenuates neurologic injury after spinal cord ischemia in rabbits.

OBJECTIVE: Paraplegia caused by spinal cord ischemia remains a serious complication after surgical repair of thoracoabdminal aortic aneurysms. Hepatocyte growth factor is a potent angiogenic and neurotrophic factor. We sought to investigate the neuroprotective effect of gene transfer of hepatocyte growth factor on spinal cord ischemia in rabbits. METHODS: Human hepatocyte growth factor expression plasmid was combined with hemagglutinating virus of Japan envelope vector. Hemagglutinating virus of Japan envelope vector containing the hepatocyte growth factor gene was injected intrathecally into the experimental rabbits, whereas control vector or saline was given to the control animals. Five days later, spinal cord ischemia was induced by means of infrarenal aortic occlusion for 30 minutes. Hind-limb motor function was assessed during a 14-day recovery period with Tarlov criteria. RESULTS: Human hepatocyte growth factor was detected in the cerebrospinal fluid 3 days after gene transfer, and the level peaked on day 5. Compared with the control animals, hepatocyte growth factor gene transfer significantly increased the capillary density in the gray matter and decreased the spinal cord edema. All rabbits pretreated with saline or control vector had hind-limb paraplegia (Tarlov score = 0) 14 days after spinal cord ischemia. However, previous transfection of the hepatocyte growth factor gene remarkably enhanced the Tarlov scores, and 8 of the 9 rabbits showed normal motor function (Tarlov score = 5) after a 14-day recovery period. Histologic examination showed that the intact motor neurons were preserved to a much greater extent in the rabbits transfected with the hepatocyte growth factor gene. CONCLUSION: Gene transfer of hepatocyte growth factor attenuates neurologic injury after spinal cord ischemia.

Total aortic arch replacement in patients with arch vessel anomalies.

BACKGROUND: The presence of anomalous arch vessels has considerable impact on aortic arch reconstruction techniques and cerebral protection methods when the separated graft technique is adopted to perform total arch replacement. We analyzed our experience of total arch replacement in patients with arch vessel anomalies. METHODS: Among the 220 patients undergoing total arch replacement at our institution, 21 patients (9.5%) had various arch vessel anomalies. Common brachiocephalic trunk was found in 8 patients (3.6%); an isolated left vertebral artery in 9 (4.1%); aberrant right subclavian artery in 3 (1.4%); and coexistent common brachiocephalic trunk and isolated left vertebral artery in 1 (0.5%). In 4 of the 9 patients with isolated left vertebral artery, preoperative diagnosis was possible with magnetic resonance angiography or three-dimensional computed tomography. In cases with common brachiocephalic trunk, total arch replacement could be performed with the usual techniques after separating the innominate and left common carotid arteries from each other. The isolated left vertebral artery was anastomosed to the left subclavian artery graft in 7 patients and to the native left subclavian artery in 2. In the aberrant right subclavian artery variety, a distal aortic anastomosis was performed distal to the orifice of this anomalous artery. The aberrant vessel was reconstructed on the right side of the trachea and esophagus. RESULTS: There was no early or in-hospital mortality. No neurologic complication attributable to the arch vessel anomalies was found. CONCLUSIONS: A precise preoperative diagnosis is very important for the selection of an appropriate surgical strategy in patients with arch vessel anomalies. Magnetic resonance angiography and three-dimensional computed tomography may be useful diagnostic tools in these patients.

Intrathecal injection of bone marrow stromal cells attenuates neurologic injury after spinal cord ischemia.

BACKGROUND: It has been shown that transplantation of bone marrow stromal cells (MSCs) into the ischemic brain improves functional outcome. We sought to investigate whether intrathecal injection of MSCs can attenuate neurologic injury of spinal cord ischemia. METHODS: Rabbit MSCs were expanded in vitro and were pre-labeled with bromodeoxyuridine. Spinal cord ischemia was induced in rabbits by infrarenal aortic occlusion. Group A and control A were subjected to a 20-minute ischemia and the ischemic duration was extended to 30 minutes in group B and control B. Two days before spinal cord ischemia, 1 x 10(8) MSCs were intrathecally injected into groups A and B, whereas vehicle alone was injected into the control groups. Hind-limb motor function was assessed during a 14-day recovery period with Tarlov criteria, and then histologic examination was performed. RESULTS: Marrow stromal cells survived and engrafted into the spinal cord 2 days after transplantation, and more MSCs were found in the lumbar spinal cord (ischemic segment) than in the thoracic spinal cord (nonischemic segment) at 14 days. Compared with their respective control groups, Tarlov scores were significantly higher in both groups A and B (p < 0.05, group A vs control A, at 2, 7, and 14 days; p < 0.05, group B vs control B, at 1, 2, 7, and 14 days, respectively). The number of intact motor neurons was much higher in the two experimental groups (p < 0.01 vs the corresponding control groups, respectively). CONCLUSIONS: Intrathecal injection of MSCs attenuates ischemic injury of spinal cord.

Right aortic arch with aberrant left subclavian artery symptomatic in adulthood.

Congenital malformations of the aortic arch are rarely found in adulthood. We describe three cases of right aortic arch with aberrant left subclavian artery with left-sided ligamentum arteriosum presenting in adulthood as vascular rings with symptoms of tracheal compression. Varying presentation as well as surgical strategy which was individualized according to the pathological anatomy of each case are discussed.

Open stent-grafting: aborted procedure in a patient with mega aorta syndrome.

OBJECTIVE: Open stent-grafting is a recent technical modification of endoluminal stent-grafting, in which a stent-graft is inserted into the descending thoracic aorta through an opening in the aortic arch, to treat distal arch aneurysms or aortic dissection. Controversy remains as to whether patients with mega aorta syndrome, or those with very wide aneurysm necks, could be candidates for stent-graft treatment--open or endoluminal. METHODS: We recently attempted open stent-grafting in a patient with mega aorta syndrome who had a distal aortic arch aneurysm. A previous attempt at surgical resection of the aneurysm through left thoracotomy ended in failure because of severe adhesion in the left lung. This time, we planned total arch replacement with open stent-graft exclusion of the aneurysm. However, open stent-grafting had to be abandoned intraoperatively due to technical difficulties as well as our lack of experience with such difficult cases. Conventional total arch replacement with elephant trunk was performed instead. RESULTS: Due to its deep location, the distal neck of the aneurysm could not be reached through median sternotomy and, therefore, the distal aortic anastomosis was performed within the aneurysm cavity. Thus, the distal portion of the aneurysm was not excluded from circulation. The future treatment plan in the present case is further complicated by the fact that a second-stage surgery through left thoracotomy will not be possible. CONCLUSIONS: Conventional total arch replacement proved rather inappropriate as a treatment strategy in the present case. Open stent-grafting might have been a more useful approach is spite of the challenges posed by the aneurysm. There needs to be a consensus as to whether patients with mega aorta syndrome or those with very wide aneurysm necks could be candidates for stent-graft treatment--open or endoluminal in difficult circumstances.

Experimental study on the protective effects of edaravone against ischemic spinal cord injury.

OBJECTIVE: Reactive free radical species are thought to be involved in ischemic spinal cord injury. We investigated the effects of edaravone (Mitsubishi Pharma Co, Tokyo, Japan), a free radical scavenger, on spinal ischemia-reperfusion injury in a rabbit model. We also sought to estimate free radicals in the spinal cord using the microdialysis method. METHODS: Spinal cord ischemia was induced in New Zealand White rabbits. The animals were then divided into 4 groups. In the first experiment, which was carried out in group A (non-edaravone treated) and group B (edaravone treated), we assessed neurologic function and evaluated spinal cord histopathology. In the second experiment, which was performed in group C (non-edaravone treated) and group D (edaravone treated), we sequentially estimated the level of free radical species in the spinal cord with the microdialysis method. RESULTS: In the first experiment group B showed better neurologic function than group A. The number of viable neurons in the spinal cord gray matter was also higher in group B than in group A. The second experiment revealed that the level of free radical species was lower in group D at 75, 90, and 150 minutes after the beginning of reperfusion compared with levels seen in group C. The appearance of free radical species in the latter group was found to have a biphasic pattern, with peaks at 75 and 150 minutes after the beginning of reperfusion. CONCLUSION: Edaravone exerted a significant protective effect on the spinal cord against ischemia-reperfusion injury by suppressing the level of free radical species, which was demonstrated with the microdialysis method.