[Subthalamic nucleus targeting and spatial variability]. / Localización bilateral y simetría del núcleo subtalámico.

AIM: The effectiveness of anatomic localization of the subthalamic nucleus (EAL) was assessed and the mapping method is described here. The symmetry of contralateral nuclei (SCN) was analyzed on 11 parkinsonian patients submitted to bilateral subthalamotomy with ablative lesioning. PATIENTS AND METHODS: To assess EAL the percentage so much of first trajectory (p1) as the total of trajectories (pt) that hit the target and the rest of subthalamic nucleus average distance (d) was calculated. The anatomic localization error (epsilon) is determined as a difference between first trajectory coordinates with those of medial determined nucleus point, through electrophysiological data as to the statistical significance of this error. SCN is analyzed by contrasting equality hypothesis at the nucleus maximum height alongside a trajectory, average electrophysiological position center and spatial distribution of all intranuclear recordings found in each hemisphere in all patients. RESULTS: The pi, pt and d obtained values were 86.36%, 86.13% and 1.41 +/- 1.01 mm respectively. The epsilon value was greater in anteroposterior direction of 1.11 +/- 0.83 mm without statistical significance. The average number of recorded trajectories for the first procedure was 6.45 and 6 for the second. The asymmetry of contralateral nucleus was not significant. CONCLUSIONS: An indirect method with CT brain images and a new electrophysiological mapping method with a multiunitary recording for first and second nucleus is safe enough and it yields a high effectiveness in anatomofunctional nucleus localization. The nucleus of a same patient are symmetrical. There is little space variability among patient non related to the differences in the intercommissural distance.

Localización bilateral y simetría del núcleo subtalámico / subthalamic nucleus targeting and spatial variability

Objetivos. Se evalúa la efectividad de localización anatómica (ELAN) bilateral del núcleo subtalámico (NST), se describe el método de cartografiado electrofisiológico y se analiza la simetría de los núcleos contralaterales (SC) en 11 pacientes con enfermedad de Parkinson, sometidos a subtalamotomía bilateral. Pacientes y métodos. Para evaluar la ELAN se calcula el porcentaje tanto de los primeros trayectos (p1) como del total de trayectos (pt) que hicieron blanco, así como la distancia promedio (d) del resto al NST. Se define el error de localización anatómica ( Epsilon ) como la diferencia entre las coordenadas del primer trayecto y las del punto medio del núcleo, determinado por la información electrofisiológica, así como la significación estadística de este error. La SC se analiza con el contraste de la hipótesis de igualdad en la máxima altura del núcleo a lo largo de un trayecto, la posición promedio del centro electrofisiológico y la distribución espacial de todos los registros intranucleares en todos los pacientes encontrado en cada hemisferio. Resultados. Los valores de p1, pt y d obtenidos fueron 86,36 por ciento, 86,13 por ciento y 1,41 ñ 1,01 mm, respectivamente. El valor de fue mayor en la dirección anteroposterior (1,11 ñ 0,83 mm), aunque sin significación estadística (test ANOVA de Kruskal Wallis para la mediana y test de Wilcoxon para muestras apareadas; p = 0,05). El número promedio de trayectos de registros para el primer proceder fue 6,45, y para el segundo, 6. La asimetría de los núcleos contralaterales no fue significativa (test ANOVA de Kruskal Wallis para la mediana y test de Wilcoxon para muestras apareadas; p = 0,05). Conclusiones. Un método indirecto con imágenes de TAC y un novedoso método de cartografiado electrofisiológico con registro multiunitario, para el primer y el segundo núcleo, son seguros y brindan una alta efectividad en la localización anatomofuncional del núcleo. Los núcleos de un mismo paciente son simétricos. Se observó poca variabilidad espacial entre pacientes, no relacionada con las diferencias en la distancia intercomisural (AU)

Aim. The effectiveness of anatomic localization of the subthalamic nucleus (EAL) was assessed and the mapping method is described here. The symmetry of contralateral nuclei (SCN) was analyzed on 11 parkinsonian patients submitted to bilateral subthalamotomy with ablative lesioning. Patients and methods. To assess EAL the percentage so much of first trajectory (p1) as the total of trajectories (pt) that hit the target and the rest of subthalamic nucleus average distance (d) was calculated. The anatomic localization error (ε) is determined as a difference between first trajectory coordinates with those of medial determined nucleus point, through electrophysiological data as to the statistical significance of this error. SCN is analyzed by contrasting equality hypothesis at the nucleus maximum height alongside a trajectory, average electrophysiological position center and spatial distribution of all intranuclear recordings found in each hemisphere in all patients. Results. The pi, pt and d obtained values were 86.36%, 86.13% and 1.41±1.01 mm respectively. The ε value was greater in anteroposterior direction of 1.11±0.83mm without statistical significance. The average number of recorded trajectories for the first procedure was 6.45 and 6 for the second. The asymmetry of contralateral nucleus was not significant. Conclusions. An indirect method with CT brain images and a new electrophysiological mapping method with a multiunitary recording for first and second nucleus is safe enough and it yields a high effectiveness in anatomofunctional nucleus localization. The nucleus of a same patient are symmetrical. There is little space variability among patient non related to the differences in the intercomisural distance (AU)