Applied neurophysiology最新文献

The purpose of this study was to assess the biochemical mechanisms underlying spinal cord stimulation (SCS). Seventeen patients with chronic pain were investigated by measuring cerebrospinal fluid concentrations of endogenous opioids and biogenic amines before and during dorsal column stimulation. Basal cerebrospinal fluid beta-endorphin levels were below the normal range. No significant change of norepinephrine, epinephrine, dopamine, beta-endorphin, beta-lipotropin, or adrenocorticotropic hormone levels were found after SCS. A 50% increase of cerebrospinal beta-endorphin and beta-lipotropin levels occurred in 6 out of 16 patients, namely those where SCS gave the major pain relief. These data confirm the derangement of the endogenous opioid system in chronic pain conditions and suggest that the beta-endorphin response to SCS could have clinical value in predicting the success of treatment.

The anatomic delineation of radiofrequency dorsal root entry zone lesions using the Nashold thermocouple electrode is presented. The sharply delineated lesions involve a major portion of the dorsal horn of the spinal cord including Rexed's lamina V and part of VI. The extent of these lesions is appropriate, based on the currently understood mechanisms of spinal generators of chronic deafferentation pain.

Lesions of the dorsal horn (DREZ operation) have been reported to be useful in reducing pain secondary to avulsion of the brachial plexus. Ten patients had the DREZ operation for this condition at The Johns Hopkins Hospital by one of us (JNC) between 1981 and 1985. Radiofrequency heat lesions were made. The patients were interviewed 7-52 months after the operation by one of two individuals not involved in the procedure to assess pain relief and postoperative complications. The mean pain relief was 85%, and there were no significant complications. It is concluded that the DREZ operation is the treatment of choice for treatment of severe pain that results from avulsion of the brachial plexus.

Animal models of dysesthesias have been established, and reveal the following major points. Dysesthesias of peripheral nerve or dorsal root origin have a central neural cause. Chronic dysesthesias of spinal origin have a cause which resides in the brain. The origins of these effects are lesions in the spinothalamic system. The causes of these effects are abnormal functionings among opiate, catecholamine, and purine pathways. Denervation supersensitivity is suggested.

The dorsal root entry zone operation was introduced in 1976 to relieve the pain of brachial plexus avulsion. Since then it has been applied to pain treatment in paraplegia, postherpetic pain, phantom limb pain and other types of of deafferentation pain. Over 400 operations have been done at the Duke University Medical Center with overall good results in 60% of pain patients.

It is possible to grow functional primary dissociated cultures and explants from stereotactic biopsies of human parkinsonian caudate nuclei. Two major classes of cells were identified on morphological grounds. The culture cells appear to be stimulated by an unidentified soluble factor(s) obtained from human fetal neuronal cells in vitro. Culture of primary neuronal and glial cells from human adult cerebral nuclei seems to be a useful tool for several research purposes and in particular for studying both trophic factor action and target effects on afferent neurons for prospective human brain grafting.

Twenty patients with intractable obsessive-compulsive neurosis were operated under local anesthesia. Each patient had a lesion produced in 1 of the 4 brain targets: anterior internal capsule, rostral cingulum, middle cingulum, and genu of the corpus callosum. Before destructive permanent lesions were produced, the target area was stimulated electrically. Stimulation gave subjective or objective reactions in 30% of the patients: diminished anxiety, 3 patients; increased anxiety, 1 patient, and motor responses, 2 patients. None experienced an obsessive reaction to stimulation. The clinical effect of surgery was usually good.