First Report of Extraspinal Lead Migration Along a Thoracic Spinal Nerve After Spinal Cord Stimulation.

BACKGROUND: Spinal cord stimulation for failed back surgery syndrome and chronic pain is a well-established treatment regimen today. Lead migration is the most common complication; mainly epidural caudal more than cranial electrode migration from the primary position is described repeatedly throughout the literature. CASE DESCRIPTION: A 60-year-old male patient with failed back surgery syndrome was eligible for spinal cord stimulation. Surgery had been performed 4 weeks before readmission with proper lead positioning of both electrodes in the midline of the epidural space. The electrode fixation mechanism at L2/3 had to be revised and was replaced with multiple ligature fixations due to the patient's slim build. He presented to our outpatient clinic with thoracic right-sided pain matching T5 with signs of overstimulation of the paravertebral muscles. X-ray imaging revealed cranial migration of 1 lead to T4 and a right-sided extraspinal migration of the other lead along a spinal nerve in T5 exiting the neuroforamen and following beneath the corresponding rib dorsally. Revision surgery was performed using a thoracic paddle electrode. CONCLUSIONS: Lead migration remains a challenge in spinal cord stimulation regardless of the fixation method. Rare unusual migration patterns in addition to simple caudal or cranial migration might pose a challenge for revision surgery and thus might reduce overall treatment efficacy.

Prognostic factors and outcome after different types of resection for temporal lobe epilepsy.

OBJECT: It is unknown whether different resection strategies for temporal lobe epilepsy (TLE) produce alterations in seizure control or neuropsychological performance. METHODS: A series of 321 patients who underwent surgery for TLE between 1989 and 1997 was submitted to a uni- and multifactorial analysis of clinical, electrophysiological, neuroimaging, neuropsychological, and surgical factors to determine independent predictors of outcome. Until 1993, most patients with TLE underwent standard anterior temporal lobectomy (ATL); beginning in 1993, surgical procedures were increasingly restricted to lesions detected on magnetic resonance (MR) imaging and the presumed epileptogenic foci: for example, amygdalohippocampectomy (AH) or lesionectomy/corticectomy began to be used more often. The mean follow-up duration in this study was 38 months. Two hundred twenty-seven patients were classified as seizure free (70.7%), and 36 patients had rare and nondisabling seizures (11.2%); these groups were summarized as having good seizure control (81.9%). Twenty-four patients attained more than 75% improvement (7.5%), and no worthwhile improvement was seen in 34 cases (10.6%); these groups were summarized as having unsatisfactory seizure control (18.1%). On unifactorial analysis the following preoperative factors were associated with good seizure control (p < 0.05): single and concordant lateralizing focus on electroencephalography studies, low seizure frequency, absence of status epilepticus, concordant lateralizing memory deficit, clear abnormality on MR images, suspected ganglioglioma or dysembryoplastic neuroepithelial tumor (DNT), and absence of dysplasia on MR images. Stepwise logistic regression revealed a model containing five factors that were predictive for good seizure control (p < 0.1): 1) clear abnormality on MR images; 2) absence of status epilepticus; 3) MR imaging-confirmed ganglioglioma or DNT; 4) concordant lateralizing memory deficit; and 5) absence of dysplasia on MR images. Seizure outcome was mainly correlated with diagnosis and clinical factors. No significant differences were found regarding different resection types performed for comparable tumors. Neuropsychological testing revealed better postoperative results after limited resections compared with standard ATL, especially with regard to attention level, verbal memory, and calculated total neuropsychological performance. CONCLUSIONS: Different strategies for surgical approaches in TLE result in equally good outcomes. Seizure outcome is mainly dependent on the diagnosis and clinical factors, whereas the neuropsychological results are more beneficial after resections limited to an epileptogenic lesion and focus.

Tumor disembrioplástico neuroepitelial: experiencia en 18 casos / Dysembryoplastic neuroepithelial tumor: experience in 18 cases

El tumor disembrioplástico neuroepitelial es una lesión muy infrecuente del sistema nervioso central, la cual fue descrita por primera vez en 1988 por Daumas-Duport e incluida en la última clasificación de tumores cerebrales de la Organización Mundial de la Salud. Nosotros comunicamos 18 casos consecutivos de DNT, en los que analizamos sus características clínicas y discutimos su diagnóstico diferencial con otras lesiones histológicamente similares asociados a epilepsia fármaco-resistente crónica. La edad media al momento de la operación y al inicio de la epilepsia fueron 27,9 años y 16,9 años respectivamente. Todos los pacientes presentaron epilepsia parcial compleja y sólo un paciente tuvo un leve déficit motor. La localización fue siempre supratentorial, 16 casos temporales y 2 frontales. La resonancia magnética (RM) mostró de regla una lesión quística, usualmente poliquística. Cinco pacientes tuvieron una cirugía previa en otra institución, 3 reacciones subtotales y 2 biopsias. Ningún paciente tuvo el diagnóstico de DNT previo a la segunda cirugía. Las operaciones fueron resecciones del DNT incluyendo el tejido epileptógeno. Un paciente con un DNT frontal localizado en ganglios basales tuvo la resección sub-total. El período de seguimiento varió entre 0.5 y 7 años (media 3,7 años). En nuestro grupo de 14 pacientes, 10 están libres de crisis y 3 presentan una reducción mayor a un 75 por ciento de sus crisis. Ningún paciente ha mostrado evidencia de recurrencia en el seguimiento con RM. La larga historia de epilepsia en nuestra serie indica que el DNT es una lesión que ha permanecido largo tiempo en el encéfalo, con lento o nulo crecimiento. El resultado post-operatorio sugiere que el DNT tiene un execlente pronóstico. Sin embargo, es aún necesario un mayor período de seguimiento, para establecer su real pronóstico en la era de la RM