[Calcification of the thoracic yellow ligament as a cause of myelopathy]. / Calcificación del ligamento amarillo torácico como causa de mielopatía.

INTRODUCTION: Ossified yellow ligaments are a rare cause of thoracic myelopathy, which has been reported mainly in Japanese patients. The lower thoracic spine is the most common site affected and symptomatic patients usually begin to develop spactic paraparesis in combination with reduced depth sensation. CLINICAL CASE: A 45 year old female that since 8 months presented progressive gait disturbance with paresthesias to both lower extremities. Neurologic examination revealed a spactic gait with exaggeration of lower extremities reflexes, positive bilateral Babinski sign and reduced depth sensation. The MRI revealed concentric narrowing of the spinal canal between D(8) to D(11) with spinal cord compression due to enlarged calcified yellow ligaments and hypertrophy of articular processes. A D(9)-D(10) laminectomy was performed, with removed of calcified yellow ligaments, and foraminotomy in affected levels. The postoperative follow up during 30 months has been uneventful. CONCLUSION: Calcified yellow ligaments are a poorly understood cause of thoracic myelopathy which should be treated as early as possible in symptomatic patients.

Calcificación del ligamento amarillo torácico como causa de mielopatía / Calcification of the thoracic yellow ligament as a cause of myelopathy

Introducción. Descrita sobre todo en la población japonesa, la calcificación del ligamento amarillo es una causa poco frecuente de mielopatía torácica. En los pacientes que presentan síntomas, éstos consisten en paraparesia espástica y trastornos de la sensibilidad profunda; los niveles torácicos inferiores son los más frecuentemente afectados. Caso clínico. Mujer de 45 años de edad que desde hacía ocho meses presentaba una inestabilidad en la marcha de carácter progresivo, y parestesias en ambos miembros inferiores que le dificultaban la deambulación. La exploración neurológica puso de manifiesto una marcha espástica, con hiperreflexia en miembros inferiores, signo de Babinski positivo bilateral y trastornos en la sensibilidad profunda. Los estudios de RM mostraron una estenosis concéntrica del canal raquídeo en los niveles D8 a D11 a expensas de la calcificación de los ligamentos amarillos, con hipertrofia de los articulares. En la intervención quirúrgica se practicó laminectomía en D9 y D10, resección de los ligamentos amarillos calcificados y foraminotomía en los niveles implicados. La evolución postoperatoria hasta la actualidad, a 30 meses de seguimiento, es favorable. Conclusiones. La mielopatía por calcificación de los ligamentos amarillos es una entidad a tener en cuenta, afecta sobre todo a la zona torácica y debe plantearse su tratamiento quirúrgico tan pronto como sea posible en los pacientes sintomáticos (AU)

Intrathecal antiepileptic drugs in experimental epilepsy.

The effect of intrathecal administration of antiepileptic drugs on electroshock-induced convulsions (maximal electroshock seizure, MES test) was investigated in an experimental study in rats. Drugs tested were phenobarbital sodium (50-800 micrograms), sodium valproate (50-6,400 micrograms) and midazolam (50-250 micrograms), delivered into the cerebrospinal fluid via a catheter placed in the upper cervical intrathecal space. Control animals were tested with saline. The animals were tested in the MES test 30 min after drug administration. Phenobarbital sodium showed a dose-related protective effect on the tonic phase of the convulsion, with a 50% effect at a dose of 200 micrograms. Sodium valproate showed a less protective effect, even when reaching doses that produced neurological symptoms. Midazolam protected at a high dose but produced a severe decrease in motor activity. The results indicate the feasibility to treat experimental convulsions by means of intrathecal injection of antiepileptic drugs.

[Analgesic and anticonvulsive effect of midazolam via intrathecal administration in the rat]. / Acción analgésica y anticonvulsionante del midazolam administrado por vía intratecal en la rata.

We have studied analgesic and anticonvulsive effect of midazolam by means of tail-flick test and electroshock respectively. The drug was administered via cervical and lumbar intrathecally in chronically implanted rats. Total doses were 50, 125, and 250 microg. Control animals received 0.3125, 0.625, 1.25 and 2.5 mg intraperitoneally. Degree of sedation was also measured with a motor activity scale with the purpose of correlating sedation with analgesic and anticonvulsive effect. Tail-flick test was carried out 5 and 30 minutes after the administration of midazolam. Results showed that lumbar intrathecal midazolam has analgesic effect in tail-flick test whereas cervical intrathecal or intraperitoneal midazolam has no analgesic effect and shows a non significant hyperalgesic trend. Cervical intrathecal and intraperitoneal midazolam has anticonvulsive effect. As sedative effect of the administered doses increases, there was also a not significant trend to shorten latency period of tail-flick test and to increase anticonvulsive effect.

[Microsurgical catheterization of the intrathecal space in the rat for chronic infusion of drugs]. / Cateterización microquirúrgica del espacio intratecal de la rata para infusión crónica de fármacos.

An original technique for placement of intrathecal catheters suitable for drug administration is described. For implantation a microsurgical laminectomy is carried out, opening the dura mater and placing the catheter under surgical microscope control. Only a few instrumentation is mandatory. The mean time for this surgery was between 15 and 20 minutes. A 10% of the animals operated on developed neurological deficits and must be dropped. The mortality rate was a 5%. No catheter malfunctions were found.