Comparison of tonic spinal cord stimulation, high-frequency and burst stimulation in patients with complex regional pain syndrome: a double-blind, randomised placebo controlled trial

BACKGROUND: Complex Regional Pain Syndrome (CRPS) is a disabling disease that is sometimes difficult to treat. Although spinal cord stimulation (SCS) can reduce pain in most patients with CRPS, some do not achieve the desired reduction in pain. Moreover, the pain reduction can diminish over time even after an initially successful period of SCS. Pain reduction can be regained by increasing the SCS frequency, but this has not been investigated in a prospective trial. This study compares pain reduction using five SCS frequencies (standard 40 Hz, 500 Hz, 1200 Hz, burst and placebo stimulation) in patients with CRPS to determine which of the modalities is most effective. DESIGN: All patients with a confirmed CRPS diagnosis that have unsuccessfully tried all other therapies and are eligible for SCS, can enroll in this trial (primary implantation group). CRPS patients that already receive SCS therapy, or those previously treated with SCS but with loss of therapeutic effect over time, can also participate (re-implantation group). Once all inclusion criteria are met and written informed consent obtained, patients will undergo a baseline assessment (T0). A 2-week trial with SCS is performed and, if successful, a rechargeable internal pulse generator (IPG) is implanted. For the following 3 months the patient will have standard 40 Hz stimulation therapy before a follow-up assessment (T1) is performed. Those who have completed the T1 assessment will enroll in a 10-week crossover period in which the five SCS frequencies are tested in five periods, each frequency lasting for 2 weeks. At the end of the crossover period, the patient will choose which frequency is to be used for stimulation for an additional 3 months, until the T2 assessment. DISCUSSION: Currently no trials are available that systematically investigate the importance of variation in frequency during SCS in patients with CRPS. Data from this trial will provide better insight as to whether SCS with a higher frequency, or with burst stimulation, results in more effective pain relief. TRIAL REGISTRATION: Current Controlled Trials ISRCTN3665525

Regulation of peripheral blood flow in Complex Regional Pain Syndrome: clinical implication for symptomatic relief and pain management

Background. During the chronic stage of Complex Regional Pain Syndrome (CRPS), impaired microcirculation is related to increased vasoconstriction, tissue hypoxia, and metabolic tissue acidosis in the affected limb. Several mechanisms may be responsible for the ischemia and pain in chronic cold CPRS. Discussion. The diminished blood flow may be caused by either sympathetic dysfunction, hypersensitivity to circulating catecholamines, or endothelial dysfunction. The pain may be of neuropathic, inflammatory, nociceptive, or functional nature, or of mixed origin. Summary. The origin of the pain should be the basis of the symptomatic therapy. Since the difference in temperature between both hands fluctuates over time in cold CRPS, when in doubt, the clinician should prioritize the patient's report of a persistent cold extremity over clinical tests that show no difference. Future research should focus on developing easily applied methods for clinical use to differentiate between central and peripheral blood flow regulation disorders in individual patients

DFNA10/EYA4 - the clinical picture.

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A função vestibular em indivíduos usuários de implante coclear Vestibular function in cochlear implant users

A ocorrência de alteração no equilíbrio no período pós-cirúrgico ao implante coclear varia de 31 a 75%. OBJETIVO: Analisar a função vestibular no período pré e pós-operatório da cirurgia de implante coclear. MATERIAL E MÉTODO: Avaliou-se a função vestibular, por meio da vectoeletronistagmografia, de 38 pacientes, no pré e pós-cirúrgico de implante coclear. RESULTADOS: A principal queixa de desequilíbrio apresentada pelos pacientes foi a tontura, seguida pela vertigem postural e pela vertigem não-postural. Dos 38 pacientes avaliados, 13% deixaram de apresentar desequilíbrio após a cirurgia de implante coclear e apenas 5% referiram piora. Houve uma melhora na sintomatologia vestibular em 13% dos pacientes, sendo que esta possibilidade pode estar relacionada ao fenômeno de compensação vestibular e pela estimulação elétrica. Entretanto, foi observada na prova calórica uma piora na funcionalidade do sistema vestibular, tanto na orelha implantada como na orelha não-implantada. Assim, não há tendência de maior comprometimento na orelha implantada. CONCLUSÃO: O estudo demonstrou que o implante coclear pode comprometer o sistema vestibular em ambas as orelhas. Entretanto, a sintomatologia vestibular ocorre em menor proporção, podendo haver melhora no desequilíbrio após a cirurgia do implante coclear.<br>Balance alterations in the postoperative of cochlear implant surgeries varies from 31 to 75%. AIM: to analyze vestibular function in the pre and postoperative periods of cochlear implanted individuals. MATERIALS AND METHODS: the vestibular function was assessed, through electronystagmography, in 38 patients, in the pre and postoperative of cochlear implant procedures. RESULTS: The main complaint of unbalance reported by patients was dizziness, followed by postural vertigo and non-postural vertigo. Results: 13% of the patients did not show any balance disorder following cochlear implant surgery and just 5% showed symptoms worsening. 13 % of the patients showed an improvement, and this could be related to the vestibular compensation phenomenon and to electric stimulation. However, it was observed, in the caloric responses, a worsening in the vestibular system function, for both implanted and non-implanted ears. Thus, there is no evidence of more damage to the implanted ear. CONCLUSION: the study showed that cochlear implant surgeries could injure the vestibular system in both ears. However, the vestibular symptoms take place in a smaller proportion, and can improve after cochlear implant surgery