Acoustic neurinomas: diagnosis and treatment

We present our experience with 83 patients with acoustic neurinomas (January 1988 to November 1996); 81 patients underwent surgery and 2 patients with intracanalicular neurinomas received conservative therapy due to their advanced age (1 case) and patient's option (1 case). The surgical approach was retrosigmoid/ trasmeatal and the goal was total removal in one procedure with preservation of facial and cochlear nerves. Radical removal of lesion was attempted in 79 cases and it was possible in 77 patients. Subtotal tumor resection was planned in 2 cases. Facial nerve function (grades 1 to III, House and Brackman) was preseved in 90% and hearing in 58% of those with preoperative hearing. Three patients died due to postoperative complications. Early diagnosis of acoustic neurinomas is the most important factor in the prognosis and is one of the most important conquest of neurophysiology and modern neuroimaging. The management of these patients still present many controversial points. This article presents the diagnostic procedures used for acoustic neurinomas, the advantages and disadvantages of the different surgical approaches and the alternative management of these lesions.Apresentamos nossa experiência no tratamento de 83 pacientes com neurinomas do acústico (Janeiro-1988 a Novembro-1996). Cirurgia foi realizada em 81 pacientes e tratamento conservador (idade avançada e escolha do paciente) em 2 casos de neurinomas intracanalicures. O objetivo da cirurgia foi ressecção radical com preservação dos nervos facial e coclear. Em 77 de 79 pacientes foi obtida remoção total. Em 2 casos foi proposta ressecção sub-total devido às más condições clínicas (1 paciente) e por tratar-se de neurofibromatose tipo 2 com lesão dos nervos facial e coclear do outro lado (1 paciente). Preservação do nervo facial (grau I a III, House e Brackman) foi possível em 90% dos casos com função facial pre-operatória normal. Dos 12 pacientes que apresentavam audição no pré-operatório, 7 mantiveram a audição. Ocorreram 3 óbitos no pós-operatório imediato. As vantagens e desvantagens dos acessos cirúrgicos mais utilizados na cirurgia do neurinoma do acústico são demonstradas. O fator mais importante no prognóstico desses pacientes é o diagnóstico precoce, possível com o desenvolvimento de novos métodos neurofisiológicos e neurorradiológicos. O tratamento no entanto pode apresentar algumas controvérsias, variando desde o simples acompanhamento clínico à remoção cirúrgica ou o uso de radiocirurgia

Visual recovery after perinatal stroke evidenced by functional and diffusion MRI: case report

BACKGROUND: After perinatal brain injury, clinico-anatomic correlations of functional deficits and brain plasticity remain difficult to evaluate clinically in the young infant. Thus, new non-invasive methods capable of early functional diagnosis are needed in young infants. CASE PRESENTATION: The visual system recovery in an infant with perinatal stroke is assessed by combining diffusion tensor imaging (DTI) and event-related functional MRI (ER-fMRI). All experiments were done at 1.5T. A first DTI experiment was performed at 12 months of age. At 20 months of age, a second DTI experiment was performed and combined with an ER-fMRI experiment with visual stimuli (2 Hz visual flash). At 20 months of age, ER-fMRI showed significant negative activation in the visual cortex of the injured left hemisphere that was not previously observed in the same infant. DTI maps suggest recovery of the optic radiation in the vicinity of the lesion. Optic radiations in the injured hemisphere are more prominent in DTI at 20 months of age than in DTI at 12 months of age. CONCLUSION: Our data indicate that functional cortical recovery is supported by structural modifications that concern major pathways of the visual system. These neuroimaging findings might contribute to elaborate a pertinent strategy in terms of diagnosis and rehabilitation

Gastrodin Inhibits Allodynia and Hyperalgesia in Painful Diabetic Neuropathy Rats by Decreasing Excitability of Nociceptive Primary Sensory Neurons

Painful diabetic neuropathy (PDN) is a common complication of diabetes mellitus and adversely affects the patients’ quality of life. Evidence has accumulated that PDN is associated with hyperexcitability of peripheral nociceptive primary sensory neurons. However, the precise cellular mechanism underlying PDN remains elusive. This may result in the lacking of effective therapies for the treatment of PDN. The phenolic glucoside, gastrodin, which is a main constituent of the Chinese herbal medicine Gastrodia elata Blume, has been widely used as an anticonvulsant, sedative, and analgesic since ancient times. However, the cellular mechanisms underlying its analgesic actions are not well understood. By utilizing a combination of behavioral surveys and electrophysiological recordings, the present study investigated the role of gastrodin in an experimental rat model of STZ-induced PDN and to further explore the underlying cellular mechanisms. Intraperitoneal administration of gastrodin effectively attenuated both the mechanical allodynia and thermal hyperalgesia induced by STZ injection. Whole-cell patch clamp recordings were obtained from nociceptive, capsaicin-sensitive small diameter neurons of the intact dorsal root ganglion (DRG). Recordings from diabetic rats revealed that the abnormal hyperexcitability of neurons was greatly abolished by application of GAS. To determine which currents were involved in the antinociceptive action of gastrodin, we examined the effects of gastrodin on transient sodium currents (INaT) and potassium currents in diabetic small DRG neurons. Diabetes caused a prominent enhancement of INaT and a decrease of potassium currents, especially slowly inactivating potassium currents (IAS); these effects were completely reversed by GAS in a dose-dependent manner. Furthermore, changes in activation and inactivation kinetics of INaT and total potassium current as well as IAS currents induced by STZ were normalized by GAS. This study provides a clear cellular basis for the peripheral analgesic action of gastrodin for the treatment of chronic pain, including PDN