Memory lateralization with 2 functional MR imaging tasks in patients with lesions in the temporal lobe.

BACKGROUND: Previous studies to determine memory lateralization with functional MR imaging (fMRI) have used encoding or recall tasks. The convergence between the results of both tasks, however, is unknown. OBJECTIVE: The objective of this study was to investigate hemispheric asymmetries of temporal lobe activity (parahippocampus and fusiform gyri) in patients with temporal lesions by using both kinds of fMRI tasks. METHODS: By using blood oxygenation level-dependent fMRI, hemispheric asymmetries of 25 consecutive patients admitted for presurgical evaluation of memory and 12 healthy control participants were studied. Activation was induced by using the picture-encoding task (processing of complex scenes) and the hometown-walking task (requiring mental navigation through one's hometown by using landmarks given by participants themselves). RESULTS: Results in the control group showed that both tasks activated the parahippocampus similarly. The picture-encoding task, however, yielded greater posterior activations in the parahippocampus than did the hometown-walking task. As observed in other studies, more than half the patients showed contralesional representation of memory in each task. It is important to note that estimated memory lateralization from each task was different in 30% of patients, and several cases showed clear discrepancies between both tasks. CONCLUSION: Although previous studies showed that both tasks were useful for evaluating memory lateralization, the present study suggested that the administration of both tasks is necessary for presurgical evaluation of memory lateralization in patients with lesions in the temporal lobe. Therefore, both encoding and recall processes should at least be considered in the evaluation of memory.

[Neurosurgical treatment of acoustic neuromas without indication for radiosurgery]. / Tratamiento neuroquirùrgico de los neurinomas del acùstico sin indicación de tratamiento con radiocirugía

The aim of this paper is to review the specific problems of the microsurgical management of the acoustic neuromas not suitable for radiosurgical treatment , that is measuring more than 8 cc in volume or 2.5 cm in maximum diameter in the cerebelopontine angle. A total of 18 lesions have been included with a mean volume of 27.4 cc, representing a lesion measuring 3.8 cm in its three main diameters. The mean follow-up has been 48.7 months. There has been no mortality. All lesions were completely excised without recurrences. The anatomic conservation of the facial nerve was achieved in the 66.7% of the cases but the functional recovery (House-Brackmann grades I-II) was reached only in the 27.8%, without any grade I case. As permanent deficit all patients had postoperative cophosis, two had trigeminal hyposthesia with corneal anesthesia and one had a cerebellar deficit. The main conclussion is that the microsurgical radical resection of large acoustic neuromas not suitable for radiosurgical treatment is followed by a high postoperative morbidity mainly related with the facial nerve lesion. Therefore, it seems rationale to design specific strategies directed to reduce and alleviate these permanent deficits.

[Memory evaluation using functional magnetic resonance: applications in preoperative patients and in Alzheimer s disease]. / Evaluacion de la memoria mediante resonancia magnetica funcional: aplicaciones en pacientes prequirurgicos y en la enfermedad de Alzheimer.

The assessment of memory functions related to medial temporal lobe has become one of the most important issues on current neuropsychology. On this communication, we review the results which our research group has achieved using two functional magnetic resonance Image procedures to assess memory function: Hometown walking task and an encoding/retrieval task using complex images. Nine patients with tumoural temporal lesions performed the hometown walking task. The results of these patients showed either a bilateral or contralesional representation of memory function. These results confirm those obtained by Jokeit, Okujava y Woermann (2001), and they seem to prove that this protocol is useful to determine the preservation of memory function in the non damaged hemisphere. On the other hand, the images encoding/retrieval task has been run by two groups of four patients diagnosed as Alzheimer disease and mild cognitive impairment, and another group of five patients who participated as a control group. According to our hypothesis, the results have shown a lower activation at the left parahippocampal gyrus in mild cognitive impairment and Alzheimer disease patients than controls, just as a lower bilateral activation in the same structure for the Alzheimer group than the control group. As a whole, our results show how important may become functional magnetic resonance image for neuropsychological assessment of memory, and as a diagnostic tool for CNS diseases.

Evaluación de la memoria mediante resonancia magnética funcional: aplicaciones en pacientes prequirúrgicos y en la enfermedad de Alzheimer / Memory evaluation using functional magnetic resonance: applications in preoperative patients and in alzheimer's disease

La evaluación de las funciones de memoria relacionadas con estructuras del lóbulo temporal medial se ha convertido en uno de los pilares más importantes en la Neuropsicología actual, dada su extrema relevancia en enfermedades como las demencias y las epilepsias temporales. En esta comunicación revisaremos los resultados que nuestro grupo de investigación ha obtenido con la utilización de sendos protocolos de evaluación de la memoria mediante resonancia magnética funcional (RMf): la tarea de `Paseo por tu Ciudad' (PPTC) y la tarea de `codificación/recuerdo' de imágenes complejas. La tarea de PPTC se ha aplicado a un grupo de nueve pacientes candidatos a neurocirugía por lesiones en el lóbulo temporal, y se obtuvo en todos ellos una representación bilateral o contralesional de la memoria. Los resultados coinciden con los obtenidos en el estudio original de Jokeit, Okujava y Woermann (2001) y parecen mostrar que este protocolo sirve para determinar la preservación o no de la función mnésica en el hemisferio lesionado. Por su parte, la tarea de codificación/recuerdo de imágenes se ha administrado a un grupo de cuatro pacientes con enfermedad de Alzheimer, cuatro con deterioro cognitivo leve y cinco participantes controles. De acuerdo con nuestras hipótesis, los resultados han mostrado una menor activación en la circunvolución parahipocampal izquierda en el grupo con deterioro cognitivo leve que en el grupo control, así como una menor activación bilateral en esas estructuras en el grupo con enfermedad de Alzheimer, si se compara con el grupo control. Nuestros resultados, en conjunto, muestran la importancia que en el futuro tendrá la RMf en la evaluación neuropsicológica de la memoria, y en el diagnóstico de las enfermedades del sistema nervioso central (AU)

he assessment of memory functions related to medial temporal lobe has become one of the most important issues on current neuropsychology. On this communication, we review the results which our research group has achieved using two functional magnetic resonance Image procedures to assess memory function: ‘Hometown walking’ task and an ‘encoding/retrieval’ task using complex images. Nine patients with tumoural temporal lesions performed the hometown walking task. The results of these patients showed either a bilateral or contralesional representation of memory function. These results confirm those obtained by Jokeit, Okujava y Woermann (2001), and they seem to prove that this protocol is useful to determine the preservation of memory function in the non-damaged hemisphere. On the other hand, the images encoding/retrieval task has been run by two groups of four patients diagnosed as Alzheimer disease and mild cognitive impairment, and another group of five patients who participated as a control group. According to our hypothesis, the results have shown a lower activation at the left parahippocampal gyrus in mild cognitive impairment and Alzheimer disease patients than controls, just as a lower bilateral activation in the same structure for the Alzheimer group than the control group. As a whole, our results show how important may become functional magnetic resonance image for neuropsychological assessment of memory, and as a diagnostic tool for CNS diseases (AU)

[Applications of functional magnetic resonance imaging in pre-surgical patients: motor, mnemonic and linguistic functions]. / Aplicaciones de la resonancia magnética funcional en pacientes prequirúrgicos: funciones motora, de memoria y lingüística.

AIMS: This paper reviews and describes cases involving useful protocols for pre-surgical evaluation in functional magnetic resonance imaging (fMRI) of the motor, mnemonic and linguistic functions. DEVELOPMENT: The application of fMRI in pre-surgical evaluation allows us to pinpoint the anatomical location of a function in relation to the lesion. This technique therefore appears as an alternative to the classical intraoperative tests, which are more aggressive and costly. The paper describes aspects and considerations of fMRI with regard to the methodology and procedure employed in its application, as well as the control of contaminating variables that can affect results. The language protocols are described in terms of lateralisation and localisation, and are divided into expressive and receptive language protocols, together with linguistic protocols for overall stimulation that allow the localisation of both expressive and receptive areas. Concerning the motor protocols, we describe the procedures for patients with and without difficulties in their movement. Lastly, we review and describe the memory protocols that give rise to bilateral stimulation in the mesial temporal areas, which allows both lateralisation and localisation of the hippocampal and parahippocampal areas that are functionally significant for the patients' memory. Each of the protocols is illustrated with cases carried out by our work team. CONCLUSIONS: The development of new protocols for pre-surgical evaluation must be guided by greater delimitation and consistency in functional stimulation, as well as analysis of the behaviour displayed.

Aplicaciones de la resonancia magnética funcional en pacientes prequirúrgicos: funciones motora, de memoria y lingüística / Applications of functional magnetic resonance imaging in pre-surgical patients: motor, mnemonic and linguistic functions

Objetivo. Este artículo revisa y presenta casos sobre protocolos útiles de evaluación prequirúrgica en resonancia magnética funcional (RMf) de las funciones motoras, mnésicas y lingüísticas. Desarrollo. La aplicación de la RMf en la evaluación prequirúrgica permite referenciar la localización anatómica de una función en relación con la lesión. En este sentido, esta técnica se plantea como alternativa a las pruebas clásicas intraoperatorias, que son más invasivas y costosas. El artículo reseña aspectos y consideraciones propias de la RMf en relación con su metodología y procedimiento de aplicación, además del control de variables contaminantes que pueden afectar a los resultados. Los protocolos de lenguaje se describen en términos de lateralización y localización, y se distinguen protocolos de lenguaje expresivo y receptivo, además de protocolos lingüísticos de activación global que permiten localizar tanto áreas expresivas como receptivas. En relación con los protocolos motores, se describen los procedimientos para pacientes con y sin dificultades de movimiento. En último lugar, se revisan y describen los protocolos de memoria que producen una activación bilateral en las áreas temporales mesiales, que permiten tanto la lateralización como la localización de las áreas hipocampales y parahipocampales funcionalmente elocuentes para la memoria de los pacientes. Cada uno de los protocolos se ilustra con casos llevados a cabo por nuestro equipo de trabajo. Conclusiones. La mayor delimitación y consistencia en la activación funcional, así como el análisis de la conducta manifiesta, deben guiar el desarrollo de nuevos protocolos de evaluación prequirúrgica (AU)

Aims. This paper reviews and describes cases involving useful protocols for pre-surgical evaluation in functional magnetic resonance imaging (fMRI) of the motor, mnemonic and linguistic functions. Development. The application of fMRI in presurgical evaluation allows us to pinpoint the anatomical location of a function in relation to the lesion. This technique therefore appears as an alternative to the classical intraoperative tests, which are more aggressive and costly. The paper describes aspects and considerations of fRMI with regard to the methodology and procedure employed in its application, as well as the control of contaminating variables that can affect results. The language protocols are described in terms of lateralisation and localisation, and are divided into expressive and receptive language protocols, together with linguistic protocols for overall stimulation that allow the localisation of both expressive and receptive areas. Concerning the motor protocols, we describe the procedures for patients with and without difficulties in their movement. Lastly, we review and describe the memory protocols that give rise to bilateral stimulation in the mesial temporal areas, which allows both lateralisation and localisation of the hippocampal and parahippocampal areas that are functionally significant for the patients’ memory. Each of the protocols is illustrated with cases carried out by our work team. Conclusions. The development of new protocols for pre-surgical evaluation must be guided by greater delimitation and consistence in functional stimulation, as well an analysis of the behaviour displayed (AU)

[Retropleural paraspinal approach in the treatment of anterolateral thoracic spinal diseases]. / Vía paraespinal retropleural en el tratamiento de la patología anterolateral de la columna torácica.

The personal experience in the treatment of the spinal and paraspinal thoracic pathology using the paraspinal retropleural approach is presented. A total of 18 patients with neoplastic, traumatic and discal lesions were operated on. Improvement of neurological disturbances and pain was noted in all patients. The surgical technique for spinal cord and root decompression and also for anterior and/or posterior stabilization of the spine is described. The paraspinal retropleural approach is compared with the anterior transthoracic approach. The advantages of the paraspinal retropleural approach are: low rate of complications; allows a very wide decompression of the neurological elements as well as an anterior and/or posterior stabilization of the spine by a single approach; and it can be easily tailored for each lesion. These advantages are enhanced in the management of lesions located in the upper thoracic or thoracocervical levels.

Vía paraespinal retropleural en el tratamiento de la patologia anterolateral de la columna torácica / Retropleural paraspinal approach for the treatment of anterolateral thoracic spinal pathology

Se presenta la experiencia personal en el tratamiento de la patología espinal y paraespinal torácica utilizando la vía de abordaje paraespinal retropleural. Se han intervenido un total de 18 pacientes con patología neoplásica, traumática y discal. Todos los pacientes mejoraron de su clínica neurológica y dolorosa. Se describe la técnica quirúrgica para el tratamiento descompresivo de la médula espinal y raíces y de estabilización anterior y/o posterior del raquis. Se compara la vía paraespinal retropleural con la vía anterior transtorácica. Las ventajas de la vía paraespinal retropleural son sus escasas complicaciones; permitir una descompresión muy amplia de las estructuras neurológicas junto a una estabilización de los elementos raquídeos anteriores y/o posteriores usando un abordaje único; y, finalmente, ser una técnica modulable a la patología concreta del paciente. Estas ventajas se incrementan a la hora de abordar lesiones situadas en el raquis torácico alto o unión toracocervical. (AU)

[Assessment of the degree of resection of high grade supratentorial gliomas with early postoperative magnetic resonance]. / Valoración del grado de resección de los gliomas supratentoriales de alto grado con resonancia magnética postoperatoria precoz.

UNLABELLED: In this paper we report the results of a prospective study in which we evaluate the degree of tumor removal of 25 supratentorial high grade gliomas by means of an MRI performed in the early postoperative period. In all cases, there was preoperative enhancement 8 patients had been previously operated on while the others had their first operation. In all cases the postoperative early MRI was performed within the first week and in 15 within the first 3 days. In order to evaluate the degree of tumor removal the presence or not of enhancement was considered and if it existed, classified as linear or nodular. RESULTS: To avoid postsurgical artifacts it is important to perform the MRI as soon as possible after surgery, especially within the first 3 days. Generally, linear enhancement disappeared on subsequent follow-up examinations, showing that it probably does no represent residual, tumor while nodular enhancement usually does. Survival with the high-grade tumors was slightly higher in the group without postoperative enhancement or linear one than in the group with nodular enhancement but the difference was not significant.

[Post-discectomy cervical fusion. Clinico-radiological study comparing iliac crest bone graft, anterior cervical plate with bone graft and cage-plate GD]. / Fusión cervical postdiscectomía. Estudio clínico-radiológico comparando el injerto óseo de cresta iliaca, placa cervical anterior con injerto óseo y placa-caja GD.

OBJECTIVE: To compare clinical and radiologically three methods of cervical arthrodesis after anterolateral one-level discectomy for non-traumatic disk disease. MATERIALS AND METHODS: Three groups of patients were studied retrospectively. In group 1 (20 patients) a tricortical autologous iliac crest bone interbody graft was used. In group 2 (10 patients) the bone graft was associated to an anterior cervical plate (Stryker). In group 3 (10 patients) a cage-plate filled with iliac crest trabecular bone was implanted (plate-cage GD). Clinical and radiological parameters were recorded preoperatively and 6-9 months postoperatively. RESULTS: There was a significant clinical improvement in all three groups, with similar complications and hospitalization time. There were not hard-ware failures. There was a significant increase in the disc height in group 3 when compared with group 1 and a significant correction of the preoperative kyphosis in group 3 in relation to both group 1 and 2: There was a significant increase in postoperative radiological stability rate and also in the operative time in groups 2 and 3 when compared with group 1. CONCLUSIONS: Cervical arthrodesis after discectomy is an useful method for treatment of cervicobrachialgia. Arthrodesis with internal fixation achieves best clinical and radiological results and it has some other advantages in relation to bone graft artrhodesis. GD cage-plate minimizes the surgical and clinical problems associated with use of bone graft and cervical plate and reaches the best radiological performances.

Microsurgical management of cerebral aneurysms based in CT angiography with three-dimensional reconstruction (3D-CTA) and without preoperative cerebral angiography.

OBJECTIVE: To study the possibilities of the microsurgical management of ruptured intracranial aneurysms with the sole preoperative information provided by computed tomography angiography with three-dimensional reconstruction (3D-CTA). METHODS: Patients were studied with 3D-CTA after diagnosis of subarachnoid hemorrhage. If the study had an adequate quality and revealed an aneurysm congruent with the clinical findings or neurological examination and/or with the location of the bleeding on computed tomography (CT) scan an early microsurgical clipping of the lesion was done. When the quality of the 3D-CTA study was not adequate or the quality being adequate displayed no lesions or the findings were not accurate enough to warrant direct microsurgical treatment, the patient was studied with cerebral digital subtraction (DS) angiography. A total of 44 consecutive patients harbouring a total of 47 intracranial aneurysms diagnosed by 3D-CTA and without preoperative DS angiography were submitted to microsurgical clipping and included in the study. RESULTS: The overall mortality was 15.9% and the favourable results evaluated 6 months after discharge by means of the Glasgow Outcome Scale reached 70.4%. All lesions were successfully clipped. Surgery was done a mean of 4.1 days after the admission bleeding. A total of four microlesions undiagnosed by 3D-CTA were found at surgery and clipped. Postoperative DS angiography and necropsy findings were also used as control of the 3D-CTA findings but no additional information was provided excepting the finding in DS angiography of an asymptomatic intracavernous aneurysm. Therefore the sensitivity of the 3D-CTA for diagnosis of symptomatic aneurysms was 100% and the overall sensitivity 90.4%. CONCLUSIONS: We have reached similar results in patients operated on with or without preoperative angiography. 3D-CTA provides very valuable anatomical information, which has an additional value in the microsurgical treatment of aneurysms of the anterior communicating artery complex. Finally, selected cases of ruptured intracranial aneurysms can be successfully managed with the preoperative information provided by 3D-CTA and without DS angiography.

Fusión cervical postdiscectomía. Estudio clínico-radiológico comparando el injerto óseo de cresta iliaca, placa cervical anterior con injerto óseo y placa-caja GD / Postdiscectomy cervical fusion. Clinico-radiological study comparing iliac crest bone graft, anterior cervical plate with bone graft and cage-plate GD

Objetivo: Comparar clínica y radiológicamente tres tipos de artrodesis cervical por vía anterior tras discectomía de un solo nivel por patología discal no traumática. Material y Métodos: Se han constituido tres grupos homogéneos estudiados retrospectivamente, donde sólo variaba la técnica de artrodesis postdiscectomía. En el grupo 1 (20 pacientes) se colocaba un injerto tricortical autólogo de cresta ilíaca. En el grupo 2 (10 pacientes) se asociaba al injerto óseo una placa cervical anterior (Stryker). En el grupo 3 (10 pacientes) se utilizaba una placa-caja (placa-caja GD) rellena de esponjosa de cresta ilíaca: Los parámetros clínicos y radiológicos se estudiaron en el preoperatorio y entre 6-9 meses en el postoperatorio. Resultados: Hubo una mejoría significativa de la cervicobraquialgia con las tres técnicas, con similares complicaciones y estancia hospitalaria. No hubo fallos del material de osteosíntesis. Hay un significativo aumento de la altura discal en el grupo 3 respecto al 1 y de la corrección de la cifosis en el grupo 3 respecto a los grupos 1 y 2. Hay un significativo aumento de la estabilidad radiológica postoperatoria y del tiempo operatorio en los grupos 2 y 3 en relación al grupo 1.Conclusiones: La discectomía asociada a artrodesis es un método efectivo en el tratamiento de la cervicobraquialgia. La artrodesis con osteosíntesis obtiene mejores resultados que la conseguida con injerto óseo. La placa-caja GD minimiza los problemas quirúrgicos y clínicos debidos a la asociación de un injerto con una placa anterior y consigue los mejores resultados radiológicos (AU)