Intraoperative Neurophysiological Monitoring in Syringomyelia Surgery: A Multimodal Approach.

Syringomyelia can be associated with multiple etiologies. The treatment of the underlying causes is first-line therapy; however, a direct approach to the syrinx is accepted as rescue treatment. Any direct intervention on the syrinx requires a myelotomy, posing a significant risk of iatrogenic spinal cord (SC) injury. Intraoperative neurophysiological monitoring (IONM) is crucial to detect and prevent surgically induced damage in neural SC pathways. We retrospectively reviewed the perioperative and intraoperative neurophysiological data and perioperative neurological examinations in ten cases of syringomyelia surgery. All the monitored modalities remained stable throughout the surgery in six cases, correlating with no new postoperative neurological deficits. In two patients, significant transitory attenuation, or loss of motor evoked potentials (MEPs), were observed and recovered after a corrective surgical maneuver, with no new postoperative deficits. In two cases, a significant MEP decrement was noted, which lasted until the end of the surgery and was associated with postoperative weakness. A transitory train of neurotonic electromyography (EMG) discharges was reported in one case. The surgical plan was adjusted, and the patient showed no postoperative deficits. The dorsal nerve roots were stimulated and identified in the seven cases where the myelotomy was performed via the dorsal root entry zone. Dorsal column mapping guided the myelotomy entry zone in four of the cases. In conclusion, multimodal IONM is feasible and reliable and may help prevent iatrogenic SC injury during syringomyelia surgery.

A rare case of an intramedullary metastasis of a myxopapillary ependymoma.

BACKGROUND: Myxopapillary ependimoma (MPE) is a benign slow-growing tumor, and it has been designated histologically as a Grade I neoplasm according to the 2016 World Health Organization classification. Despite the benign character, dissemination and metastasis have occasionally been reported. The retrograde dissemination to other levels of the neuraxis is extremely rare, being more frequent to the intracranial compartment. CASE DESCRIPTION: We hereby present a case of medullary metastasis of cauda equina MPE, with a history of having undergone a subtotal resection and postoperative adjuvant radiotherapy. The patient presents complaints of night dorsal pain attributable to intradural metastasis twenty-one years after the first surgical intervention. CONCLUSION: The case reported highlights the importance of long follow-up in patients with MPE, since the possibility of secondary seeding to distant craniospinal sites or local spinal sites after surgery, and radiotherapy should be considered in metastatic disease.

[Treatment of trigeminal neuralgia: an update and future prospects of percutaneous techniques]. / Tratamiento de la neuralgia del trigemino: actualizacion y perspectivas futuras de las tecnicas percutaneas.

INTRODUCTION: Trigeminal neuralgia is one of the most severe facial pain syndromes. The annual incidence varies between 4-13% and has a significant effect on patients' quality of life. When the pain cannot be controlled by pharmacological treatment, several different surgical options can be considered. The choice of technique will be based on observational studies and its application depends on the experience of each centre. AIMS: To assess the effectiveness and level of evidence of pharmacological and surgical treatment in trigeminal neuralgia, and to analyse the current role of percutaneous techniques in the treatment of this pathology. DEVELOPMENT: The initial treatment of trigeminal neuralgia is pharmacological and carbamazepine is the only drug with a sufficiently high level of evidence. The percutaneous surgical techniques are effective and easy to apply, but the tendency for relapses to appear means there is a preference for vascular microdecompression. Yet, there are no reports of comparative studies that determine the superiority of a technique with a good level of evidence. The three most commonly used percutaneous techniques, balloon compression, glycerol rhizotomy and thermocoagulation by radiofrequency, were reviewed. This last technique is the one that has undergone the greatest development in recent years, with the emergence of neurophysiological techniques that make it possible to optimise results. CONCLUSIONS: The selection of a surgical technique for use in trigeminal neuralgia does not have much backing from randomised clinical trials. The new procedures in the application of radiofrequency can improve the treatment prospects of this pathology.

TITLE: Tratamiento de la neuralgia del trigemino: actualizacion y perspectivas futuras de las tecnicas percutaneas.Introduccion. La neuralgia del trigemino es uno de los sindromes de dolor facial mas graves. La incidencia anual varia entre el 4-13% y altera de forma significativa la calidad de vida de los afectados. Cuando el dolor no puede controlarse con tratamiento farmacologico, existen diferentes opciones quirurgicas. La seleccion de la tecnica esta basada en estudios observacionales y su aplicacion depende de la experiencia de cada centro. Objetivos. Evaluar la efectividad y el nivel de evidencia del tratamiento farmacologico y quirurgico en la neuralgia del trigemino, y analizar el papel actual de las tecnicas percutaneas en el tratamiento de esta patologia. Desarrollo. El tratamiento inicial de la neuralgia del trigemino es el farmacologico y la carbamacepina es el unico farmaco con suficiente nivel de evidencia. Las tecnicas quirurgicas percutaneas son efectivas y de facil aplicacion, pero la tendencia a la recidiva conduce a la preferencia por la microdescompresion vascular. Sin embargo, no hay estudios comparativos que determinen la superioridad de alguna tecnica con buen nivel de evidencia. Se han revisado las tres tecnicas percutaneas mas utilizadas, la compresion con balon, la rizotomia con glicerol y la termocoagulacion por radiofrecuencia. Esta ultima es la que ha presentado mayor desarrollo en los ultimos años, con la aparicion de tecnicas neurofisiologicas que pueden optimizar los resultados. Conclusiones. La seleccion de una tecnica quirurgica en la neuralgia del trigemino no esta bien apoyada por ensayos clinicos aleatorizados. Los nuevos procedimientos en la aplicacion de la radiofrecuencia pueden mejorar las perspectivas del tratamiento de esta patologia.

Deep Brain Stimulation Influences Brain Structure in Alzheimer's Disease.

BACKGROUND: Deep Brain Stimulation (DBS) is thought to improve the symptoms of selected neurological disorders by modulating activity within dysfunctional brain circuits. To date, there is no evidence that DBS counteracts progressive neurodegeneration in any particular disorder. OBJECTIVE/HYPOTHESIS: We hypothesized that DBS applied to the fornix in patients with Alzheimer's Disease (AD) could have an effect on brain structure. METHODS: In six AD patients receiving fornix DBS, we used structural MRI to assess one-year change in hippocampal, fornix, and mammillary body volume. We also used deformation-based morphometry to identify whole-brain structural changes. We correlated volumetric changes to hippocampal glucose metabolism. We also compared volumetric changes to those in an age-, sex-, and severity-matched group of AD patients (n = 25) not receiving DBS. RESULTS: We observed bilateral hippocampal volume increases in the two patients with the best clinical response to fornix DBS. In one patient, hippocampal volume was preserved three years after diagnosis. Overall, mean hippocampal atrophy was significantly slower in the DBS group compared to the matched AD group, and no matched AD patients demonstrated bilateral hippocampal enlargement. Across DBS patients, hippocampal volume change correlated strongly with hippocampal metabolism and with volume change in the fornix and mammillary bodies, suggesting a circuit-wide effect of stimulation. Deformation-based morphometry in DBS patients revealed local volume expansions in several regions typically atrophied in AD. CONCLUSION: We present the first in-human evidence that, in addition to modulating neural circuit activity, DBS may influence the natural course of brain atrophy in a neurodegenerative disease.