Neuroplastic changes related to pain occur at multiple levels of the human somatosensory system: A somatosensory-evoked potentials study in patients with cervical radicular pain.
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Studies suggest that pain may play a major role in determining cortical rearrangements in the adult human somatosensory system. Most studies, however, have been performed under conditions whereby pain coexists with massive deafferentation (e.g., amputations). Moreover, no information is available on whether spinal and brainstem changes contribute to pain-related reorganizational processes in humans. Here we assess the relationships between pain and plasticity by recording somatosensory-evoked potentials (SEPs) in patients who complained of pain to the right thumb after a right cervical monoradiculopathy caused by compression of the sixth cervical root, but did not present with clinical or neurophysiological signs of deafferentation. Subcortical and cortical potentials evoked by stimulation of digital nerves of the right thumb and middle finger were compared with those obtained after stimulation of the left thumb and middle finger and with those obtained in a control group tested in comparable conditions. Amplitudes of spinal N13, brainstem P14, parietal N20 and P27, and frontal N30 potentials after stimulation of the painful right thumb were greater than those of the nonpainful left thumb and showed a positive correlation with magnitude of pain. This right-left asymmetry was absent after stimulation of the patients' middle fingers and in control subjects. Results suggest that chronic cervical radicular pain is associated with changes in neural activity at multiple levels of the somatosensory system. The absence of correlation between the amplitude of spinal, brainstem, and cortical components of SEPs suggests that enhancement of cortical activity is not a simple amplification of subcortical enhancement. (+info)
Muscle fiber type distribution in multifidus muscle in cases of lumbar disc herniation.
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A study was conducted to analyze the distribution and diameter of muscle fiber types in samples of the medial paravertebral lumbar muscle, i.e., multifidus muscle, obtained from 76 patients who underwent surgery for disc herniation. The samples were compared with 41 control samples of corresponding muscle tissue taken from 41 young healthy subjects who had died a sudden death. Histochemical analysis of fibers associated with myofibrillar adenosine triphosphatase (ATPase) revealed the presence of Type I fibers (slow-twitch fibers) and of Type IIA and IIB fibers (fast-twitch fibers) in both the experimental and control samples. The respective percentage of muscle fibers was calculated and their diameters were measured. Type I fibers predominated in both groups and were significantly larger in diameter than Type IIA and IIB fibers. Both fast-twitch fiber types were distributed in almost equal proportions in the healthy women. In the healthy men, Type IIA fibers prevailed. In the healthy females, the percentage of Type I fibers was found to be slightly higher than in the males, but the diameter of all fiber types was respectively smaller. In the females who had undergone surgery, Type I fibers were significantly larger in diameter than those of the healthy subjects. On the other hand, the diameters of all muscle fiber types were significantly larger, and the percentage of both fast-twitch fibers were Idwer in the samples from men who underwent surgery, as compared to the healthy tissue samples. The morphometric changes in the multifidus muscle at the level of the protruded disc observed by the histochemical method for demonstration of myofibrillar ATPase could not be related to the compressed nerve root in the majority of cases in our study. (+info)
Comparison of efficacy and side effects of epidural tramadol and morphine in patients undergoing laminectomy: a repeated dose study.
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Tramadol acts through multiple mechanisms and has a low risk of post operative respiratory depression. We compared the efficacy of epidural tramadol with that of morphine for postoperative analgesia in these patients. The demographic data and the summed pain intensity difference scores (SPID) were similar in both the groups. The time to first supplementary dose was significantly shorter in the tramadol group compared to the morphine group (p<0.05). No patient in either group suffered respiratory depression. (+info)
Surgical results of lumbar disc herniation in the elderly.
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We investigated the surgical results of lumbar disc herniation in the elderly. Ten elderly patients underwent surgical treatment between 1990 and 1999. There were 7 males and 3 females with a mean age of 68.2 years (range: 60~85 years). Thirteen patients in their 20s and 30s were used as a control. Preoperatively, severe leg pain and gait disturbance, and higher rates of negative straight leg-raising were shown in the elderly group. Higher levels of herniation and higher graded disc degeneration were shown compared with the young. The mean total of the Japanese Orthopedic Association score in the elderly group improved from 5.1 points to 13.1 points postoperatively, and that in the young group improved from 6.9 points to 14.5 points. The recovery rate was 82.6% in the elderly group and 94.3% in the young group. Postoperatively, the recovery of gait disturbance in the elderly group tended to be poor compared with the young group. The elderly patients would not tolerate bed rest and would often do poorly if kept recumbent and in pain for long periods of time. Satisfactory results are being sought with regard to the operative management of lumbar disc herniation in the elderly. (+info)
Exposure of the porcine spine to mechanical compression: differences in injury pattern between adolescents and adults.
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Recent studies of the spine in adolescents who have sustained trauma have shown injuries to the growth zone, whereas injuries to the vertebral body have been described in other studies of only adults. There are also reports on different clinical signs and radiological findings in adolescents with lumbar disc herniation when compared to adults. In order to find an explanation for these differences between adolescents and adults, this experimental study was performed. Six cadaveric lumbar motion segments (vertebral body-disc-vertebral body) obtained from three young male pigs and six lumbar motion segments obtained from three mature male pigs were tested in axial compression to failure. All units were examined with plain radiography and magnetic resonance imaging before and after compression. After the compression, histological samples were taken from the injury site. In the adolescents, a fracture was consistently found in the endplate through the posterior part of the growth zone, displacing the anulus fibrosus with a bony fragment at the point of insertion to the vertebra. This type of injury could not be detected in any of the adults; instead, there was a fracture of the vertebra in four cases, and in two cases, a rupture of the anulus fibrosus without a bony fragment was seen. This study showed that, when compressed to failure, the weakest part of the lumbar spine of the adolescent pig differs from that of the mature pig in the same way that studies on human spinal units have shown. (+info)
Application of short-time magnetic resonance examination for intervertebral disc diseases in dogs.
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The usefulness of magnetic resonance (MR) is already established, but it has a disadvantage of requiring a long scanning time. A short-time examination is more or less needed so as to be more practical in veterinary clinics. A protocol of the short-time MR examination was devised based on parameters determined, and validity of the protocol was assessed through the diagnosis of clinical cases with intervertebral disc diseases. With this protocol, it was possible to complete an MR examination for the spine within 15 min. The MR images and myelographic findings were correlated well in this study, suggesting the short-time protocol of MR examination can be used in the clinical diagnosis of spinal diseases. (+info)
The distress and risk assessment method (DRAM).
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Our aim was to judge the influence of preoperative psychological disturbance on the outcome of lumbar discectomy. We evaluated 66 patients, before and after operation, using a self-administered questionnaire. Disability was assessed using the Oswestry disability index and psychological disturbance the Distress and Risk Assessment Method (DRAM) score. Patients were classified as normal, at risk or distressed, and the outcome of surgery in the three groups was compared at a follow-up of six months. The mean self-reported preoperative disability was significantly higher in those with psychological disturbance. A total of 54 patients (82%) returned completed postoperative questionnaires. Postoperative disability scores at six months were not significantly different in the three risk groups. Psychological disturbance improved after surgery. Our study suggests that the early outcome of lumbar discectomy is not affected by preoperative psychological disturbance. We conclude that a patient with a symptomatic prolapsed intervertebral disc should not be denied surgery on the basis of preoperative psychological assessment. (+info)
Intradural disc herniation at the T1-T2 level.
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Intradural disc herniations comprise 0.26-0.30% of all herniated discs. Five percent are found in the thoracic, 3% in the cervical, and 92% in the lumbar region. Although intradural disc herniation may be suspected on preoperatively made CT scans, myelograms, and MRI scans, establishing the diagnosis prior to the surgery is difficult. We present a case of the patient with severe neurological deficits, caused by intradural thoracic disc herniation at T1-T2 interspace, which required surgical treatment. The symptoms were relieved immediately after surgery. This is the first description of an intradural disc herniation at that level. (+info)