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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two patients had the initial complaint of fluctuating paraparesis, which was most evident at menstruation. One patient had a semimonthly fluctuating deficit. Spinal cord compression and ischemia, secondary to the vascular mass, were considered the most likely mechanisms. Blood levels of estrogen and progesterone during the menstrual cycle may have had a contributory effect. Fluctuating spinal cord deficits associated with a consistent portion of the menstrual cycle should alert the physician to the possibility of an arteriovenous malformation of the spinal cord.
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PMID:Spinal cord vascular malformations with symptoms during menstruation. Report of two cases. 90 18

The cervical spinal cord was compressed at one (C5) or two (C4,C5) levels in eight awake dogs by advancing screws through the vertebral bodies into the spinal canal until minimal limb weakness occurred. Ischemia of the cervical cord was produced by ligation of vertebral and spinal arteries in four anesthetized dogs, of which two had previously undergone cord compression at two levels. The neurological and histological findings were studied. By means of antipyrine [14C]autoradiography, qualitative changes of blood flow in dogs with compression and/or ischemia of the cervical spinal cord were compared to flow patterns in normal dogs. The authors conclude that the neurological and histological changes produced by spinal cord compression, ischemia and their combination correlate with altered patterns of blood flow within the cervical spinal cord.
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PMID:Experimental cervical myelopathy: autoradiographic studies of spinal cord blood flow patterns. 126 34

Spinal trauma can originate from internal or external sources. Injuries to the spinal cord can be classified as either concussive or compressive and concussive. The pathophysiologic events surrounding spinal cord injury include the primary injury (compression, concussion) and numerous secondary injury mechanisms (vascular, biochemical, electrolyte), which are mediated by excessive oxygen free radicles, neurotransmitter and electrolyte alterations in cell membrane permeability, excitotoxic amino acids, and various other biochemical factors that collectively result in reduced SCBF, ischemia, and eventual necrosis of the gray and white matter. Management of acute spinal cord injuries includes the use of a high-dose corticosteroid regimen within the initial 8 hours after trauma. Sodium prednisolone and methylprednisolone, at recommended doses, act as oxygen radical scavengers and are anti-inflammatory. Additional considerations are the stability of the vertebral column, other conditions associated with trauma (i.e., pneumothorax), and the presence or absence of spinal cord compression, which may warrant surgical therapy. Vertebral fractures or luxations can occur in any area of the spine but most commonly occur at the junction of mobile and immobile segments. Dorsal and dorsolateral surgical approaches are applicable to the lumbosacral and thoracolumbar spine and dorsal and ventral approaches to the cervical spine. Indications for surgical intervention include spinal cord compression and vertebral instability. Instability can be determined from the type of fracture, how many of the three compartments of the vertebrae are disrupted, and on occasion, by carefully positioned stress studies of fluoroscopy. Decompression (dorsal laminectomy, hemilaminectomy, or ventral cervical slot) is employed when compression of the spinal cord exists. The hemilaminectomy (unilateral or bilateral) causes less instability than dorsal laminectomy and therefore should be used when practical. The preferred approach for atlantoaxial subluxation is ventral, and the cross pinning, vertebral fusion technique is used for stabilization. Fracture luxations of C-2 are repaired with small plates on the ventral vertebral body. The thoracic and upper lumbar spine is stabilized with dorsal fixation techniques or combined dorsal spinal plate/vertebral body plate fixation. Several methods of fixation can be used with lower lumbar or lumbosacral fractures, including the modified segmental technique and the combined dorsal spinal plate/Kirschner-Ehmer technique.
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PMID:Spinal trauma. Pathophysiology and management of traumatic spinal injuries. 164 21

Two patients with Down's syndrome undergoing intracardiac operations had segmental and generalized myoclonic movements postoperatively and eventual brain death. Electroencephalography in 1 patient showed no seizure despite the presence of the myoclonic movements. Computed tomographic scan showed possible cerebellar hemorrhage. Ultrasound showed cerebral edema when the pupils became fixed and dilated. Because known postoperative neurologic complications could not fully explain the clinical course, and the myoclonic movements suggested spinal origin, we considered the possibility of atlantoaxial instability causing spinal cord damage related to perioperative head and neck positioning. Postmortem study on the second patient revealed 50% reduction of the spinal canal with hyperextension and 90-degree external rotation of the head and neck. In contrast, similar maneuvers in 3 infants without Down's syndrome resulted in only mild spinal canal narrowing. Although the myoclonic movements could be explained by spinal cord compression at the atlantoaxial level, the explanation for the eventual brain death is unclear. However, kinking of the vertebral arteries related to the positioning could have caused cerebellar ischemia, hemorrhage, and increased intracranial pressure. We believe that attention to the problem might bring further answers in the future.
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PMID:Perioperative spinal canal narrowing in patients with Down's syndrome. 183 20

The purpose of this study was to report the effects of spinal cord compression, ischemia, and distraction on clinical status, and somatosensory (SEP) and neurogenic-motor evoked potentials (NMEPs) in animals. The authors also reported their clinical experience with NMEPs elicited from humans undergoing surgery for spinal deformities. Results from the animal studies indicate that NMEPs are more sensitive and specific to the effects from spinal cord compression, ischemia, and distraction than SEPs. In every situation, NMEPs always correlated with the animal's post-surgical clinical status, while SEPs demonstrated an unacceptable false positive and false negative rate. In the 111 clinical cases in which NMEPs were administered, reliable NMEPs were easily elicited in more than 90% of the cases. In the remaining cases, no reliable NMEPs could be recorded because of procedural errors, which have been resolved. The results from this study suggest that the use of NMEPs should be considered as an adjunct to SEPs when monitoring spinal cord function during surgery.
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PMID:Sensitivity and specificity of somatosensory and neurogenic-motor evoked potentials in animals and humans. 306 Oct 24

Spinal cord ischemia presenting as acute paraplegia is an uncommon occurrence not previously reported in the emergency medicine literature. Paraplegia due to spinal ischemia is seen most commonly after intraoperative aortic manipulation; however, acute hypotension and prolonged cardiopulmonary resuscitation are also reported settings. The differential diagnosis of acute, non-traumatic paraplegia includes mechanical spinal cord compression, acute transverse myelitis, and polyneuritis.
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PMID:Ischemic injury to the spinal cord as a cause of transient paraplegia. 358 53

Three patients presented with hand wasting and weakness secondary to mid-cervical spinal cord compression. This was due to cervical spondylosis in two patients and a meningioma in one case. This phenomenon is probably similar to that seen with foramen magnum lesions and may be due to spinal cord ischemia distal to the compression, secondary to venous stasis.
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PMID:Hand wasting due to mid-cervical spinal cord compression. 366 74

The authors report 4 cases of ossification of the posterior vertebral ligament. In 3 cases, the cervical spine was involved (mainly C4-C6), two included thoracic lesions. Three cases showed signs of spinal cord compression. Only one case was operated on. The authors review the literature. The authors discuss the classification, and the etiology, together with the possible relationship between the disease and ankylosing hyperostosis. Finally the pathogenesis is studied: the authors believe that spinal ischemia plays a very important role.
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PMID:[Ossification of the posterior longitudinal ligament]. 677 51

Numerous investigators endeavored to make clear pathophysiological changes in a traumatic spinal cord lesion. The development of neuroscience contributed to have an influence on methods of these researches. This study was undertaken to assess electrophysiological changes resulting from variable periods of experimental spinal cord compression or ischemia by using the evoked spinal cord potentials. Experiments were performed on dogs. Following laminectomies at Th7-9 and L3-4 levels under anesthesia, cord injuries were produced at the lower thoracic level by inflation of an extradurally placed balloon which produced slow graded compression of cord dorsum. Evoked spinal cord potentials to sciatic nerve stimulation were recorded from bipolar electrodes in the midline dorsal subdural space at the operative sites. The normal wave forms of two responses consisted of initially positive triphasic potentials (P1, N1, P2). The conduction velocity of the ascending afferent from the leg was found on the average to be 54.8 +/- 9.7 m/sec between lumbar and dorsal cord. On the basis of the conduction velocities and the responses to stimulus intensities, the afferent volley recorded in the present experiments might reflect synaptic cord afferent pathways originated without Group I fibers in the cord dorsum which were situated ipsilateral to the stimulated nerve. After inflation of the balloon with 0.1 cc of water, spinal canal narrowing rate increased to 14.3 +/- 2.9%. The evoked spinal cord potentials in the lead rostral to the site of compression began to decrease in amplitude. When more water was added into the balloon up to 0.4 - 0.6 cc, spinal canal narrowing rate was enhanced to 42.5 - 77.7% in which potentials were abolished. P2 wave was the first to be abolished and subsequently N1, P1 disappeared in order. On the other hand, the potentials reappeared after decompression in the reverse of their disappearance in order. Responses in dogs with complete recovery from paraplegia returned to the precompression wave pattern both in the amplitude and in latency. On the contrary, in dogs with spastic paraparesis, the recovery of wave form was shown as P1, N1 or P1, N1 with depressed P2. Despite this variability, the evoked response from animals with reversible cord injury were discernible in the early period of spinal shock phase. The degree of recovery varied and had no linear relationship to the recovery grade of clinical symptoms. The experimental cord ischemia was made by inflation of a balloon catheter which was inserted from femoral artery into the upper thoracic aorta. The evoked spinal cord potentials were recorded at the midthoracic and lumbar level. Changes of wave form resulting from the ischemic period of 30 minutes were first the amplitude loss of N1 and subsequently that of P2, P1. On the other hand, the responses gradually returned to their pre-ischemic characteristic about 30 minutes after circulatory reestablishment...
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PMID:[Clinical application of the evoked spinal cord potentials. Part 1. Neurophysiological assessment of the evoked spinal cord potentials in experimental cord trauma - with reference to cord compression and ischemia (author's transl)]. 728 22

There exists the view that ischemia in the spinal cord accounts for the paralysis caused by cervical spondylotic myelopathy (CSM), but little work has been done to study the change of spinal cord blood flow (SCBF) in CSM. To clarify this situation, the experimental model designed by Tanaka (1978) was used as a model of CSM (Fig. 1). Among 27 cats in which the spinal canal was narrowed between C4 and C6, 13 cats developed delayed paralysis 33 weeks after operation in an average. Spinal cord blood flow was measured by the reference sample method using isotopelabeled microspheres of 15 +/- 3 mu in diameter. The mean SCBF values for each spinal segments in normal animals ranged from 23.0 g/min . 100 g in T11 to 40.2 g/min . 100 g in C8, resulting in that blood flow in the cervical and lumbar enlargements was constantly higher than that in the other regions of the cord (Fig. 3). The mean blood flow values for the gray matter, ventral white matter, lateral white matter, and dorsal white matter in cervical region were 99.1, 5.0, 5.9, and 11.4 g/min . 100 g respectively, without significant difference between each spinal segments (Fig. 4). In an animal with acute spinal cord compression, the SCBF decreased significantly 15 minutes after spinal cord compression was induced (Figs. 5, 6). On the other hand, in two delayed paralysis animals SCBF in the narrowed segments was within normal limits (Figs. 5, 6). These results suggest that paralysis as seen in CSM may develop without ischemia of the spinal cord.
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PMID:[Experimental study of cervical spondylotic myelopathy--spinal cord blood flow in cervical canal stenosis (author's transl)]. 731 Feb 8


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