[Surgical treatment of spinal dural arteriovenous fistulas: Management and long-term results in a series of patients operated in an Argentinian Center]. / Resultados a largo plazo del tratamiento quirúrgico de las fístulas arteriovenosas durales espinales en un Centro argentino.

INTRODUCTION: Spinal dural arteriovenous fistula (SDAVF) is a rare vascular disease, of unknown etiology, frequently underdiagnosed. Treatment can be microsurgical or endovascular. METHODS: Retrospective and monocentric analysis of 12 SDAVF patients treated by microsurgery between 2010 and 2021. Parameters including age, sex, pre and postoperative clinical condition were analyzed according to modified Aminoff-Logue and Rankin scales. Diagnostic studies such as magnetic resonance imaging (MRI), magnetic resonance angiogram (MRA) and spinal digital subtraction angiography (DSA), were evaluated for lesion level, as were surgical results. RESULTS: Twelve patients (10 men and 2 women), average age: 60 years, were operated. The interval from symptom onset to diagnosis was < 12 months in all cases except one (32 months). SDAVF locations were thoracic in 8 cases, between T6 and T12, 3 at lumbar spine (L1-L2) and at S1 in one case, with no difference regarding side. The Adamkiewicz artery was identified in 5 cases at L1, 2 at D12, 2 at D10, 2 at D9 and 1 at D7 (7 left-sided and 5 right-sided). Three of the 12 patients operated had undergone prior embolization. Postoperative neurological outcomes showed: 2 patients remained stable and 10 improved one or more points on the mRs; no postoperative complications were observed. Follow-up MRI images improved in all cases and spinal DSA was negative at 6 months. Average follow-up was 40 months (range 6 to 122) and no patient presented recurrence. CONCLUSION: Microsurgical treatment of SDAVF proved to be efficient, with low morbidity and lower recurrence rates compared to endovascular results.

Introducción: La fístula dural arteriovenosa espinal (FDAVE) es una enfermedad vascular frecuentemente subdiagnosticada. El tratamiento puede ser microquirúrgico o endovascular. Métodos: Estudio retrospectivo de una serie de pacientes con FDAVE tratados por microcirugía entre los años 2010 y 2021. Fueron evaluados parámetros como edad, sexo, cuadro clínico pre y postoperatorio medido con las escalas de Aminoff-Logue y Rankin modificada (mRs). Los estudios diagnósticos se utilizaron para determinar nivel lesional y resultados quirúrgicos. Resultados: Se incluyeron doce pacientes (10 hombres y 2 mujeres) con un promedio de edad de 60 años. El tiempo de evolución del cuadro clínico al diagnóstico fue menor a 12 meses salvo un caso de 32 meses. Las FDAVE fueron localizadas, 8 a nivel dorsal, 3 a nivel lumbar y una a nivel sacro. La arteria de Adamkiewicz se identificó en 5 casos en L1, 2 en D12, 2 en D10, 2 en D9 y un caso en D7. De los 12 pacientes operados, 3 fueron embolizados previamente; dos permanecieron estables en su evolución y 10 mejoraron uno o más puntos del mRs. No hubo complicaciones en el postoperatorio. Todos mostraron mejoría del edema medular en resonancia magnética y la angiografía digital, luego de los 6 meses, fue negativa. El seguimiento promedio fue de 40 meses con un rango de 6 a 122 meses y ningún paciente presentó recidiva de la FDAVE. Conclusión: El tratamiento quirúrgico de las FDAVE es un método muy eficaz, de baja morbilidad y menor tasa de recurrencia comparado con el tratamiento endovascular.

Anatomy of the Great Posterior Radiculomedullary Artery.

BACKGROUND AND PURPOSE: Although considerable variability exists as to the overall caliber of radiculomedullary arteries, dominant radiculomedullary arteries such as the artery of Adamkiewicz exist. The existence of a great posterior radiculomedullary artery has attracted little attention and has been a matter of debate. The aim of this anatomic study was to determine the presence or absence of the great posterior radiculomedullary artery. MATERIALS AND METHODS: We performed microsurgical dissection on formaldehyde-fixed cadaveric human spinal cords. The artery of Adamkiewicz in the spinal cord specimens (n = 50) was injected with colored latex until the small-caliber arterial vessels were filled and the great posterior radiculomedullary artery was identified. The course, diameter, and location of great posterior radiculomedullary artery were documented. RESULTS: A great posterior radiculomedullary artery was identified in 36 (72%) spinal cord specimens. In 11 (22%) specimens, bilateral great posterior radiculomedullary arteries were present. In 13 cases (26%), a unilateral left-sided great posterior radiculomedullary artery was identified. In 11 cases (22%), a unilateral right-sided great posterior radiculomedullary artery was identified. In 1 specimen (2%), 3 right-sided great posterior radiculomedullary arteries were noted. The average size of the great posterior radiculomedullary arteries was 0.44 mm (range, 0.120-0.678 mm on the left and 0.260-0.635 mm on the right). CONCLUSIONS: A great posterior radiculomedullary artery is present in most (72%) individuals. The authors describe the microsurgical anatomy of the great posterior radiculomedullary artery with emphasis on its morphometric parameters as well as its implications for spinal cord blood supply. Variations of the arterial supply to the dorsal cord are of great importance due to their implications for ischemic events, endovascular procedures, and surgical approaches.

Innervation of the blood vessels of the spinal cord: a comprehensive review.

There is growing evidence that the nervous system influences spinal cord vasculature. However, most descriptions of the spinal cord have paid little attention to this important aspect. We reviewed the literature on the innervation of spinal cord vessels with an emphasis on findings that may be applicable to human medicine. Multiple neurotransmitters and competing theories have been implicated in the neural regulation of spinal cord blood vessels. Identifying valid mechanisms of pathogenesis could be beneficial to human patients with spinal cord lesions. We discuss the various findings on the neural mechanisms behind spinal cord blood flow. Further investigation is warranted due to the current emphasis on comparative animal studies without corresponding corroborative human findings.

The influence of low-level laser irradiation on spinal cord injuries following ischemia-reperfusion in rats.

PURPOSE: To investigate if low level laser therapy (LLLT) can decrease spinal cord injuries after temporary induced spinal cord ischemia-reperfusion in rats because of its anti-inflammatory effects. METHODS: Forty eight rats were randomized into two study groups of 24 rats each. In group I, ischemic-reperfusion (I-R) injury was induced without any treatment. Group II, was irradiated four times about 20 minutes for the following three days. The lesion site directly was irradiated transcutaneously to the spinal direction with 810 nm diode laser with output power of 150 mW. Functional recovery, immunohistochemical and histopathological changes were assessed. RESULTS: The average functional recovery scores of group II were significantly higher than that the score of group I (2.86 ± 0.68, vs 1.38 ± 0.09; p<0.05). Histopathologic evaluations in group II were showed a mild changes in compare with group I, that suggested this group survived from I-R consequences. Moreover, as seen from TUNEL results, LLLT also protected neurons from I-R-induced apoptosis in rats. CONCLUSION: Low level laser therapy was be able to minimize the damage to the rat spinal cord of reperfusion-induced injury.

The influence of low-level laser irradiation on spinal cord injuries following ischemia- reperfusion in rats

To investigate if low level laser therapy (LLLT) can decrease spinal cord injuries after temporary induced spinal cord ischemia-reperfusion in rats because of its anti-inflammatory effects. Forty eight rats were randomized into two study groups of 24 rats each. In group I, ischemic-reperfusion (I-R) injury was induced without any treatment. Group II, was irradiated four times about 20 minutes for the following three days. The lesion site directly was irradiated transcutaneously to the spinal direction with 810 nm diode laser with output power of 150 mW. Functional recovery, immunohistochemical and histopathological changes were assessed. The average functional recovery scores of group II were significantly higher than that the score of group I (2.86 ± 0.68, vs 1.38 ± 0.09; p<0.05). Histopathologic evaluations in group II were showed a mild changes in compare with group I, that suggested this group survived from I-R consequences. Moreover, as seen from TUNEL results, LLLT also protected neurons from I-R-induced apoptosis in rats. Low level laser therapy was be able to minimize the damage to the rat spinal cord of reperfusion-induced injury.(AU)

The influence of low-level laser irradiation on spinal cord injuries following ischemia- reperfusion in rats

PURPOSE:To investigate if low level laser therapy (LLLT) can decrease spinal cord injuries after temporary induced spinal cord ischemia-reperfusion in rats because of its anti-inflammatory effects.METHODS: Forty eight rats were randomized into two study groups of 24 rats each. In group I, ischemic-reperfusion (I-R) injury was induced without any treatment. Group II, was irradiated four times about 20 minutes for the following three days. The lesion site directly was irradiated transcutaneously to the spinal direction with 810 nm diode laser with output power of 150 mW. Functional recovery, immunohistochemical and histopathological changes were assessed.RESULTS:The average functional recovery scores of group II were significantly higher than that the score of group I (2.86 ± 0.68, vs 1.38 ± 0.09; p<0.05). Histopathologic evaluations in group II were showed a mild changes in compare with group I, that suggested this group survived from I-R consequences. Moreover, as seen from TUNEL results, LLLT also protected neurons from I-R-induced apoptosis in rats.CONCLUSION:Low level laser therapy was be able to minimize the damage to the rat spinal cord of reperfusion-induced injury.

Tratamiento quirúrgico de aneurisma de la arteria espinal posterior roto: reporte de un caso y revisión de la literatura / Surgical treatment of ruptured posterior spinal arteryaneurysm. case report and literature review

Los aneurismas de la arteria espinal posterior (AEP) se presentan en su gran mayoría asociados a patologías que generan aumento del flujo arterial como malformaciones o fístula arteriovenosas y también asociadas a enfermedades del colágeno. Su presentación aislada es rara, con 11 casos publicados en la literatura a nuestro conocimiento. Presentamos una paciente de 56 años de edad, usuaria de anticoagulantes orales por accidente cerebro vascular antiguo no secuelado secundario a fibrilación auricular, que se presenta con dolor lumbar súbito no irradiado, al que luego se agrega paraplejia fláccida. En resonancia nuclear magnética se observa hemorragia subaracnoidea espinal con importante compresión medular secundaria. Estudio con angiografía demostró aneursima de aspecto disecante en arteria espinal posterior. Debido a pequeño calibre de arteria nutricia se optó por tratamiento quirúrgico. Angiografia de control mostró exclusión completa de aneurisma. En los controles posteriores la paciente ha mostrado recuperación progresiva del déficit neurológico. Tanto el tratamiento endovascular como el quirúrgico se han reportado para la exclusión de aneurismas de la AEP. El presente caso muestra que el tratamiento quirúrgico precoz es una alternativa sobre todo si además se requiere realizar descompresión medular.

Aneurysms of the Posterior spinal artery (PSA) usually present secondary to high-flow pathologies such as arteriovenous malformations or dural arteriovenous fistulas, also can be associated whit collagen diseases. Isolate PSA aneurysms are rare, whit 11 cases reported, to our knowledge. We present a 56 years old patient, user of oral anticoagulant for an old isquemic stroke, secondary to atrial fibrillation, who presented whit subit lumbar pain and flaccid paraplejia. The magnetic resonance image shows an extensive spinal subarachnoid hemorrhage and secondary medular compression. Spinal angiography study demonstrated a dissecting aneurysm of PSA. Due to the small size of the artery, on which the aneurysm was located, surgical treatment was performed. Follow up angiography shows complete exclusion of the lesion. The patient has had a progressive recovery on her deficit. Both surgical and endovascular treatment have been reported. The present case shows that early surgical treatment is an option, especially if medular decompression is needed.

Intrathecal injection of human umbilical cord blood stem cells attenuates spinal cord ischaemic compromise in rats.

OBECTIVES: Spinal cord ischaemia with resulting paraplegia remains a devastating and unpredictable complication after thoraco-abdominal aortic surgery. With the advent of stem cell therapy and its potential to induce nervous tissue regeneration processes, the interest in the use of these cells as a treatment for neurological disorders has increased. Human stem cells, derived from the umbilical cord, are one of the strong candidates used in cell therapy for spinal cord injury because of weak immunogenicity and ready availability. We sought to evaluate the use of human umbilical cord blood stem cells (HUCBSCs) to attenuate the neurological effects of spinal cord ischaemia induced by high thoracic aorta occlusion. METHODS: Forty Wistar rats were randomized to receive intrathecal injection of 10 µl phosphate buffered saline (PBS) solution containing 1 × 10(4) HUCBSCs, 30 min before (Tpre group: n = 10) and 30 min after (Tpos group: n = 10) descending thoracic aorta occlusion by intraluminal balloon during 12 min. Control groups received only PBS solution (Cpre group: n = 10; and Cpos group: n = 10). During a 28-day observational period, motor function was assessed by a functional grading scale (Basso, Beattie and Bresnahan). Segments of thoracolumbar spinal cord specimens were analysed for histological and immunohistochemical assessment for detection and quantification of human haematopoietic cells (CD45(+)) and apoptosis (transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling). RESULTS: Overall mortality was 12 animals (30%). Therefore, the observational sample was composed of 28 animals. All groups showed similar incidence of paraplegia and mortality. The mean motor function scores showed no difference during time between the animals of each group, excepting for the Tpos group, which improved from 8.14 (±8.6) to 14.28 (±9.8) (P < 0.01). A treatment-by-time interaction was detected among animals that received HUCBSCs 30 min after ischaemia, with BBB scores higher from Days 14 to 28 compared with the first observational day with statistical difference (P = 0.01). Number of viable neurons was higher in the Tpos group (P = 0.14) and the incidence of apoptosis was lower in the same animals (P = 0.048), but showed no difference with its respective control. We confirmed the presence of CD45(+) cells 4 weeks after intrathecal injection in both therapeutic groups but mainly in the Tpos group. CONCLUSIONS: Intrathecal transplantation of HUCBSCs is feasible, and it improved spinal cord function, when they were delivered 30 min after spinal cord ischaemia, in a model of endovascular descending thoracic aorta occlusion in rats. Human umbilical cord blood is one of the potentially useful sources of stem cells for therapy of spinal cord ischaemia.

Optical monitoring and detection of spinal cord ischemia.

Spinal cord ischemia can lead to paralysis or paraparesis, but if detected early it may be amenable to treatment. Current methods use evoked potentials for detection of spinal cord ischemia, a decades old technology whose warning signs are indirect and significantly delayed from the onset of ischemia. Here we introduce and demonstrate a prototype fiber optic device that directly measures spinal cord blood flow and oxygenation. This technical advance in neurological monitoring promises a new standard of care for detection of spinal cord ischemia and the opportunity for early intervention. We demonstrate the probe in an adult Dorset sheep model. Both open and percutaneous approaches were evaluated during pharmacologic, physiological, and mechanical interventions designed to induce variations in spinal cord blood flow and oxygenation. The induced variations were rapidly and reproducibly detected, demonstrating direct measurement of spinal cord ischemia in real-time. In the future, this form of hemodynamic spinal cord diagnosis could significantly improve monitoring and management in a broad range of patients, including those undergoing thoracic and abdominal aortic revascularization, spine stabilization procedures for scoliosis and trauma, spinal cord tumor resection, and those requiring management of spinal cord injury in intensive care settings.

[Acute non-traumatic myelopathy in children and adolescents]. / Mielopatías agudas no traumáticas en niños y adolescentes.

The term 'acute myelopathies'--referred to a spinal cord dysfunction--represent a heterogeneous group of disorders with distinct etiologies, clinical and radiologic features, and prognoses. The objective of this review is to discuss the non-traumatic acute myelopathies. Acute myelopathy can be due to several causes as infective agents or inflammatory processes, such as in acute myelitis, compressive lesions, vascular lesions, etc. The clinical presentation is often dramatic with tetraparesis or paraparesis, sensory disturbances and bladder and/or bowel dysfunction. History and physical examination are used to localize the lesion to the root or specific level of the cord, which can guide imaging. Different syndromes are recognized: complete transverse lesion, central grey matter syndrome, anterior horn syndrome, anterior spinal artery syndrome, etc). The first priority is to rule out a compressive lesion. If a myelopathy is suspected, a gadolinium-enhanced MRI of the spinal cord should be obtained as soon as possible. If there is no structural lesion such as epidural blood or a spinal mass, then the presence or absence of spinal cord inflammation should be documented with a lumbar puncture. The absence of pleocytosis would lead to consideration of non inflammatory causes of myelopathy such as arteriovenous malformations, fibrocartilaginous embolism, or possibly early inflammatory myelopathy. In the presence of an inflammatory process (defined by gadolinium enhancement, cerebrospinal fluid pleocytosis, or elevated cerebrospinal fluid immunoglobulin index), one should determine whether there is an inflammatory or an infectious cause. Different virus, bacterias, parasites and fungi have to be considered as autoimmune and inflammatory diseases that involve the central nervous system.

TITLE: Mielopatias agudas no traumaticas en niños y adolescentes.El termino 'mielopatias agudas' se refiere a una disfuncion de la medula espinal y representa un grupo heterogeneo de trastornos con distintas etiologias y caracteristicas clinicas (imaginologicas y de pronostico). El objetivo de esta revision es tratar las mielopatias agudas no traumaticas. La mielopatia aguda puede deberse a varias causas, como agentes infecciosos o procesos inflamatorios, compresion y lesiones vasculares, entre otros. La presentacion clinica es a menudo dramatica con tetraparesia o paraparesia, alteraciones sensitivas y disfuncion de la vejiga o del intestino. La historia y el examen fisico se utilizan para localizar la lesion o el nivel especifico de la medula, que puede guiar la solicitud de la imagen. La primera prioridad es descartar una lesion compresiva. Si se sospecha una mielopatia, debe obtenerse tan pronto como sea posible una resonancia magnetica medular con gadolinio. Si no hay ninguna lesion estructural, entonces la presencia o ausencia de inflamacion de la medula espinal debe documentarse con una puncion lumbar. La ausencia de pleocitosis daria lugar a la consideracion de causas no inflamatorias como malformaciones arteriovenosas, embolia fibrocartilaginosa o posiblemente el inicio de una mielopatia inflamatoria. En presencia de un proceso inflamatorio (realce con gadolinio, pleocitosis o elevado indice de inmunoglobulina en el liquido cefalorraquideo), se debera determinar si hay una inflamacion o una causa infecciosa. Se tienen que considerar hongos, bacterias, parasitos y virus, asi como enfermedades autoinmunes e inflamatorias que involucran al sistema nervioso central.

[Pathogenesis of spinal cord injuries and mechanisms of repair induced by olfactory ensheathing cells]. / Patogenia de la lesion medular y mecanismos de reparacion inducidos por las celulas de la glia envolvente olfatoria.

INTRODUCTION: Spinal cord injury is a catastrophic event with permanent consequences during the all life. Treatment research has been based in the development of therapies that reduce the discapacity, but since the nineties there has been an important advance and several cellular transplants have been tested in spinal cord animal models, like Schwann cells, astrocytes and olfactory and olfactory ensheathing cells (OEC). AIM: Detailed account of spinal cord injury pathogeny, primary and secondary, and the OEC mechanisms for the regeneration effects that have been described in the literature. DEVELOPMENT: After the trauma, spinal cord injury develops in two phases, the primary injury with characteristics compression lesions, and the secondary produce for several factors that occur in parallel and include: vascular, cellular and molecular factors, and glial scar formation. The most of spinal cord models and OEC transplants have been reported functional recovery, remielinization and axonal regeneration. These cells exert their action in a direct way by producing grow factors and in an indirect way inducing directly neuronal an axonal regeneration and remielinization. CONCLUSIONS: OEC are a therapeutic option in patients with spinal cord injury, because they induce in a direct or indirect way, neuronal and axonal regeneration, remielinization, decrease the glial scar and produce other effects that conduce a functional recovery.

TITLE: Patogenia de la lesion medular y mecanismos de reparacion inducidos por las celulas de la glia envolvente olfatoria.Introduccion. La lesion medular es un evento catastrofico, cuyas consecuencias persisten durante toda la vida del paciente. La investigacion en tratamiento se ha basado principalmente en el desarrollo de terapias que reduzcan la discapacidad, pero desde los anos noventa hay un avance significativo y se han probado varios trasplantes celulares en modelos animales de lesion medular, celulas de Schwann, astrocitos y celulas de la glia envolvente olfatoria (CGEO). Objetivo. Hacer un recuento detallado de la patogenia de la lesion medular primaria y secundaria y de los mecanismos por los cuales las CGEO inducirian sus posibles efectos regenerativos descritos en la bibliografia. Desarrollo. Despues del traumatismo, la lesion se desarrolla en dos fases, la primaria se caracteriza por las lesiones de compresion y la secundaria se produce por una serie de factores que se dan en paralelo y que incluyen factores vasculares, celulares, moleculares y formacion de cicatriz glial. La mayoria de los modelos de lesion medular y trasplante con CGEO han comunicado recuperacion funcional, remielinizacion y regeneracion axonal. Estas celulas ejercen su accion de manera indirecta a traves de la produccion de factores de crecimiento y de manera directa induciendo regeneracion neuronal, axonal y remielinizacion. Conclusiones. Las CGEO son una opcion terapeutica en pacientes con lesion medular debido a que inducen de modo directo o indirecto regeneracion neuronal, axonal, remielinizacion de axones, disminucion de cicatriz glial y otros efectos que conducen a la recuperacion funcional.

Gurltia paralysans (Wolffhügel, 1933): description of adults and additional case reports of neurological diseases in three domestic cats from southern Chile.

Adults of Gurltia paralysans were obtained from veins of the spinal cord subarachnoid space from three domestic cats presenting with chronic paraparesis/paraplegia from rural areas of southern Chile. Four adult nematodes were collected (2 males and 2 females) were recovered from cat 1, 14 adult nematodes (12 females and 2 males) from cat 2, and 12 nematodes (10 females and 2 males) were collected from cat 3. Parasite induced lesions that compromised subarachnoid vein microvasculature at the thoracic, lumbar, sacral spinal cord segments extending to conus medularis. Female nematodes measured 25 mm long (range=25-30 mm) and 0.1mm wide. Male measured a mean of 16 mm length (range=13-18 mm) with a body diameter of 0.1mm (range=0.08-0.15 mm). The present study described structural features of G. paralysans, a rare parasite first reported in the 1930s, and provides additional reports on associated clinical and pathological findings in naturally infected domestic cats.

Quadriplegia recovery after hemi-section and transplant model of spinal cord at the level of C5 and C6.

A spinal cord hemi-section with a homologous transplant of medullar tissue at the level of C5-C6 and preservation of the anterior spinal artery was used to evaluate the histological characteristics such as quantity and quality of axons, myelin index and blood vessels after quadriplegia recovery. Vascular changes after spinal injury results in severe endothelial damage, axonal edema, neuronal necrosis and demyelinization as well as cysts and infarction. Preservation of the anterior spinal artery has demonstrated clinical recuperation; therefore, in addition to the lesion we included a homologous transplant to visualize changes at a cellular level. Two groups of dogs (hemi-section and transplant) went through a traumatic spinal cord hemi-section of 50% at the level of C5-C6. The transplant group formed by animals which simultaneously had 4 mm of spinal cord removed and the equal amount substituted from a donor animal at the level of C5-C6 corresponding to the half right side; both preserving the anterior spinal artery. Histological evaluation of all groups took place at days 3 (acute) and 28 (chronic) post-operation. Changes of degeneration and axonal regeneration were found in the hemi-section and transplant groups at acute and chronic time, as well as same quadriplegia recovery at chronic time in the hemi-section and transplant groups which closely related to mechanisms which participate in regeneration and functional recuperation due to the preservation of the anterior spinal artery and presence of new blood vessels.

Change in central kinin B2 receptor density after exercise training in rats.

Cardiovascular responses elicited by the stimulation of kinin B2 receptors in the IV cerebral ventricle, paratrigeminal nucleus or in the thoracic spinal cord are similar to those observed during an exercise bout. Considering that the kalikrein-kinin system (KKS) could act on the cardiovascular modulation during behavioral responses as physical exercise or stress, this study evaluated the central B2 receptor densities of Wistar (W) and spontaneously hypertensive rats (SHR) after chronic moderate exercise. Animals were exercise-trained for ten weeks on a treadmill. Afterwards, systolic blood pressure decreased in both trained strains. Animals were killed and the medulla and spinal cord extracted for B2 receptor autoradiography. Trained animals were compared to their sedentary controls. Sedentary groups showed specific binding sites for Hoe-140 (fmol/mg of tissue) in laminas 1 and 2 of the spinal cord, nucleus of the solitary tract (NTS), area postrema (AP), spinal trigeminal tract (sp5) and paratrigeminal nucleus (Pa5). In trained W a significant increase (p<0.05) in specific binding was observed in the Pa5 (31.3%) and NTS (28.2%). Trained SHR showed a significant decrease in receptor density in lamina 2 (21.9%) of the thoracic spinal cord and an increase in specific binding in Pa5 (36.1%). We suggest that in the medulla, chronic exercise could hyper stimulate the KKS enhancing their efficiency through the increase of B2 receptor density, involving this receptor in central cardiovascular control during exercise or stress. In the lamina 2, B2 receptor might be involved in the exercise-induced hypotension.

Conus perimedullary arteriovenous fistula in a child: unusual angio-architectural features and pathophysiology.

INTRODUCTION: The perimedullary arteriovenous fistulas are located on the pial surface and are usually supplied by spinal medullary arteries, that is, either by the anterior or posterior spinal arteries, with no intervening nidus between the feeder arteries and the venous drainage. The clinical findings are, more commonly, caused by progressive radiculomedullary ischemic processes secondary to steal vascular mechanism. As the vascular supply to the spinal cord and to the arteriovenous fistulas (AVF) is not shared with one another, the vascular steal phenomenon cannot be implicated in this case's physiopathology. Most probably, the mass effect caused by the giant venous dilatation was the pathophysiological mechanism involved in this lesion. CASE REPORT: The authors describe the case of a 6-year-old girl with an intradural ventral arteriovenous fistula, with a giant venous dilatation, fed directly by L2 and L3 radiculomedullary arteries at the conus medullaris. There was no arterial supply to the fistula from the anterior or posterior spinal arteries. Selective spinal angiography showed an arteriovenous fistula supplied directly by two radiculomedullary arteries, with a large draining vein caudally. Interposing the arterial and venous vessels was a giant venous aneurysmal dilatation located ventral to the conus medullaris and extending from L3 to T6. The patient was successfully treated by a surgical approach through a laminotomy from L3 to T11. CONCLUSION: The type IV-C spinal arteriovenous malformations or perimedullary AVFs are rare lesions predominately described at the conus medullaris with various types of angio-architecture and controversial treatment.

Neuroprotective effects of diltiazem in rabbits with occluded aorta

OBJECTIVE: In the present study, we aimed to determine the protective effect of the perfusion of the distal aorta with diltiazem and ringer lactate solution on the spinal cord. METHODS: Twenty-seven New Zealand rabbits were used in which spinal cord ischemia was provided by occlusion of the aorta for thirty minutes. Experimental animals were divided into four groups: group A (n=4), the sham operation group; group B (n=8) in which intraaortic balloon occlusion alone was applied; group C (n=7), ringer lactate group in which ringer lactate was perfused into distal aorta at a rate of 40 ml/kg, hr, following intraaortic balloon occlusion; group D (n=8) diltiazem group in which diltiazem 40 mg/kg, hr, in Ringer lactate was perfused into distal aorta following intraaortic balloon occlusion. Motor function of hind limbs was evaluated by Tarlov's scoring system. After observation, spinal cords were removed for histopathological evaluation. RESULTS: The degree of histopathological injury was well correlated with neurological function. The most severe histopathological injury and neurological dysfunction occurred in group B, followed by group C, D and A respectively. No injury or neurological dysfunction occurred in the sham group. CONCLUSIONS: The protective effect of diltiazem on both histopathological injury and neurological function was significant in comparison with control groups.

OBJETIVO: O objetivo do presente trabalho é determinar o efeito protetor da perfusão na aorta distal com diltiazem e solução de Ringer lactato na medula espinal. MÉTODOS: Foram usados 27 coelhos da raça New-Zeland, nos quais se provocou isquemia da medula espinal por meio de oclusão da aorta durante 30 minutos. Os animais experimentais foram divididos em quatro grupos: grupo A (n=4), o grupo de cirurgia simulada (pseudocirurgia); o grupo B (n=8) no qual se aplicou somente a oclusão do balão intraaórtico; grupo C (n=7), o grupo do Ringer lactato, no qual a solução de Ringer lactato foi perfundida na aorta distal após oclusão do balão intra-aórtico; grupo D (n=8), grupo do dialtiazem, no qual 40 mg/kg/h de diltiazem, em solução de Ringer lactato, foram perfundidas na aorta distal após oclusão do balão intra-aórtico. A função motora dos membros posteriores foi avaliada pelo sistema de escore de Tarlov. Após observação, as medulas espinais foram removidas para avaliação histopatológica. RESULTADOS: O grau de lesão histopatologica estava bem correlacionado com a função neurológica. Lesões histopatológicas e disfunções neurológicas mais graves ocorreram no grupo B, seguido pelos grupos C, D e A, respectivamente. Não ocorreu nenhuma lesão ou disfunção neurológica no grupo de cirurgia simulada. CONCLUSÕES: O efeito protetor do diltiazem na lesão histopatológica e na função neurológica foi significativo em comparação com os grupos-controle.