Thalamic deep brain stimulation for post-traumatic neuropathic limb pain: Efficacy at five years' follow-up and effective volume of activated brain tissue.

Chronic neuropathic pain affects 7%-10% of the population. Deep brain stimulation (DBS) has shown variable but promising results in its treatment. This study prospectively assessed the long-term effectiveness of DBS in a series of patients with chronic neuropathic pain, correlating clinical results with neuroimaging. Sixteen patients received 5 years' post-surgical follow-up in a single center. Six had phantom limb pain after amputation and 10 had deafferentation pain after traumatic brachial plexus injury. Patient-reported outcome measures were completed before and after surgery, using VAS, UWNPS, BPI and SF-36 scores. Neuroimaging evaluated electrode location and effective volumes of activated tissue (VAT). Two subgroups were created based on the percentage of VAT superimposed upon the ventroposterolateral thalamic nucleus (eVAT), and clinical outcomes were compared. Analgesic effect was assessed at 5 years and compared to preoperative pain, with an improvement on VAS of 76.4% (p=0.0001), on UW-NPS of 35.2% (p=0.3582), on BPI of 65.1% (p=0.0505) and on SF-36 of 5% (p=0.7406). Eight patients with higher eVAT showed improvement on VAS of 67.5% (p=0.0017) while the remaining patients, with lower eVAT, improved by 50.6% (p=0.03607). DBS remained effective in improving chronic neuropathic pain after 5 years. While VPL-targeting contributes to success, analgesia is also obtained by stimulating surrounding posterior ventrobasal thalamic structures and related spinothalamocortical tracts.

[Trigeminal neuralgia caused by contra lateral cerebellopontine angle tumor. A case report]. / Neuralgia del trigémino provocada por un tumor del ángulo ponto-cerebeloso contralateral. Caso clínico.

In most cases, trigeminal neuralgia is due to compression of the trigeminal nerve in the zone of entrance at the pons by vascular structures. About 1% of cases, have trigeminal neuralgia associated with the presence of ipsilateral lesion of cerebellar-pontine angle. Rarely, trigeminal neuralgia may be due to contralateral posterior fossa tumors. We present a case of a 37-year- old patient who presented with right trigeminal neuralgia and harboured a left acoustic neuroma of significant dimension. Facial pain completely disappeared after tumor removal.

[Cavernous malformation of the pineal region. Case report and review of the literature]. / Malformación cavernosa de la región pineal. Caso clínico y revisión de la literatura.

Cavernous malformations rarely occur in the pineal region with only 21 reported to date. Although its diagnosis is not easy because of the extreme rareness of this condition, the presence of this lesion can be suspected based on its typical radiological findings. We report the case of a 57-year-old woman presented with desorientation, somnolence and diplopy. The CT-scan showed an acute hemorrhage in the pineal region and triventricular hydrocephalus. An MRI suggested a cavernous malformation. The patient was operated with total en-bloc removal of the lesion. We conclude that surgical exploration and total resection is the treatment of choice when the diagnosis of cavernous angioma is suspected of the basis of neuroimaging.

Foraminal L5-S1 disc herniation and conus medullaris syndrome: a vascular etiology?

A 56-year-old man presented with a conus medullaris syndrome lumbar magnetic resonance imaging showed only a right foraminal disc herniation at the L5-S1 level. Operative removal of the protrusion was followed by prompt neurological improvement. We postulate that the discrepancy between extent of compression shown by imaging and the neurological findings may reflect vascular compression of the artery of Desproges-Gotteron, an anatomical variant.