Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

EPs can be used in the operating room for monitoring the integrity of many levels of the central nervous system. SEPs can monitor the spinal cord, brain stem, and cerebral hemispheres. Such monitoring can alert the surgical team to the presence of complications, allowing prompt correction in some cases so as to prevent postoperative neurologic deficits. Monitoring can be done from stimulation of either the lower or upper extremity. Recordings can be taken over the scalp or can be made from electrodes put into the surgical site itself. Monitoring of the spinal cord is most often done for surgery involving scoliosis, spinal tumors, or arteriovenous malformations, and during crossclamping of the thoracic aorta. Animal models and human surgical experience has shown that monitoring the posterior columns is an effective way to assess the status of the motor pathways of the spinal cord, because the two pathways are both affected in almost all acute circumstances. Monitoring can also assess the functional status of the cerebral hemispheres. This is most often applied during carotid endarterectomy or repair of aneurysms of the carotid artery and its branches. Occasionally, this has also been applied to monitoring the cortex during cardiopulmonary bypass. Such EP monitoring does not cover the wide areas of cortex that can be monitored using EEG, but the EPs do tend to change and disappear at a level of ischemia nearer to the true critical level. Intraoperative median nerve EPs can also be used to identify the hand level of the motor and somatosensory cortex. Such identification of motor cortex can help guide neurosurgeons in their choice of how or where to perform a biopsy, excision, and the like. Overall, intraoperative evoked potential monitoring is becoming widespread because it is a practical way to help avoid neurologic complications, and it can be carried out using equipment already available in many hospitals. A substantial further review in this field can be found in Evoked Potential Monitoring in the Operating Room.
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PMID:Use of somatosensory evoked potentials for intraoperative monitoring of cerebral and spinal cord function. 307 Mar 43

A 27-year-old man was diagnosed with the unilateral dissociated motor loss of the forearm and hand muscles. His medical image findings were completely different from those of other reports such as so called flexion myelopathy (abnormal anterior displacement of the dura mater and the spinal cord against the posterior wall of the vertebral body in neck flexion). Our patient demonstrated lateral shift of the spinal cord to the right attributed to high thoracic scoliosis and disk herniation at the level of C6-7. The right side of the spinal cord was compressed between the disk herniation and the right lamina. In this condition, circulatory insufficiency probably occurred and resulted in damage of the anterior horn, which was selectively vulnerable for ischemia in the spinal cord.
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PMID:Dissociated motor loss in forearm and hand muscles: case report. 767 Feb 17

Somatosensory evoked potentials (SEPs) were recorded in 165 patients from 185 operations for scoliosis and major spinal distortions, lumbar or cervical stenosis, post-traumatic malunions, or tumors. They were obtained by percutaneous stimulation of right and left median and tibial posterior nerves, and recorded on the scalp as recently, motor potentials (MPs) have also been obtained, by a trans-spinous stimulation rostral to the level of intervention. The protocol consists of pre- and post-operative recordings, as well as a continuous intra-operative monitoring. Neuromonitoring is justified in operations implying neurological risks, particularly scoliosis. A durable disappearance of SEPs and MPs was always associated with post-operative neurological disorders. Transient disappearances, not associated with neurological disorders, have been observed during certain manoeuvres such as vertebral traction, osteosynthesis, placing trans-pedicular screws or hooks, leading the surgeon to modify the operation. The role of medullary ischemia on the degradation of electrophysiological signals, obvious in cardiovascular decompensations, seems predominant in the post-operative occurrence of neurological impairment. During the post-operative period, SEPs allow one to discriminate between organic disorders and subjective complaints; they help in diagnosing hematomas, and distinguish between radicular and spinal cord injuries.
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PMID:[Somatosensory evoked potentials during spinal orthopedic surgery in adult patients]. 832 29

The tethered spinal cord syndrome is more often encountered in children, but does also occur in adults. Its clinical spectrum comprises low back pain, neurological deficits such as distal motor weakness and trophic and sensory disturbances in the legs, urological symptoms and such musculoskeletal signs as scoliosis or foot deformities. In addition, cutaneous lesions or subcutaneous lipomas in the lumbosacral region may be indirect signs of an intraspinal pathology. This consists in a tight, thickened and sometimes shortened filum terminale, an intraspinal lipoma, intradural scar formation or other lesions that lead to conus fixation. The common mechanism of injury of these types of pathologies is an impairment of longitudinal movement of the spinal cord, especially the conus medullaris, which subsequently leads to chronic local ischemia. Diagnosis is most readily achieved by magnetic resonance imaging. Treatment is aimed at the restoration of cord mobility by means of microsurgical release of the conus, the cauda equina and the filum terminale with the aid of cauda equina neuromonitoring. Further progression can be effectively halted; in fact almost half of the patient actually improve. Therefore, every patients presenting with the clinical diagnosis of tethered cord syndrome should be offered specialized surgical treatment.
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PMID:[Tethered spinal cord syndrome in adults]. 927 57

Controlled arterial hypotension understood to be a mean arterial pressure (MAP) between 55 and 60 mmHg is often used as a complementary technique in anesthesia even though it is not without complications and associated mortality even in young patients. During surgery to reduce scoliosis in a young boy, MAP fell to 60 mmHg accompanied by bilateral loss of sensory and motor evoked potentials (SEP and MEP). Detecting the absence of SEP and MEP allowed us to prevent medullar injury due to ischemia secondary to hypotension, once possible surgical or technical causes had been ruled out. We believe that monitoring SEP and MEP is useful not only to the surgeon but also to the anesthesiologist.
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PMID:[Neurophysiological monitoring during scoliosis surgery using controlled hypotension]. 1110 18

In scoliosis surgery, intraoperative somatosensory evoked potential (SSEP) monitoring has reduced the incidence of postoperative neurologic deficits. Many factors affect the amplitude and latency of SSEP waveforms during surgery. Somatosensory evoked potential amplitude decreases with ischemia and anoxia because of temporal dispersion of the afferent volley and conduction block in damaged axons. In conjunction with surgical manipulations, minor drops in blood pressure may result in substantial SSEP changes that reverse when perfusion pressure is increased. Irreversible anoxic injury to central nervous system white matter with loss of SSEP waveforms is dependent on calcium influx into the intracellular space. Somatosensory evoked potential monitoring may be less sensitive for detecting acute insults in the presence of preexisting white matter lesions. Increased extracellular potassium from acute baro-trauma can block axonal conduction transiently even when there is no axonal disruption. Marked temperature-related drops in SSEP amplitude may occur after exposure of the spine but before instrumentation and deformity correction. Hypothermia may increase false-negative outcomes. Short-interval double-pulse stimulation may improve the sensitivity of the SSEP in detecting early ischemic changes. For neurosurgical procedures on the spinal cord the use of SSEP monitoring in improving postoperative outcome is less well established.
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PMID:Mechanisms of signal change during intraoperative somatosensory evoked potential monitoring of the spinal cord. 1247 86

Although the literature on infections transmitted via transfused blood focuses on viruses, Yersinia enterocolitica can also cause severe infections in patients receiving transfusions. A 13-year-old patient developed severe sepsis after an autologous blood transfusion contaminated with Y. enterocolitica. The patient was an otherwise healthy female undergoing posterior spinal fusion for congenital scoliosis. Prior to surgery, the patient donated blood for perioperative and postoperative use. A few days before the donation, she had complained of abdominal pain and was experiencing mild diarrhea. The patient received four units of packed red blood cells (PRBCs) during the surgery. Intraoperatively, the patient developed fever up to 103.6 degrees F, became hypotensive requiring epinephrine and dopamine, and developed metabolic acidosis with serum bicarbonate concentration dropping to 16 mmol/l. The surgery team believed the patient was experiencing malignant hyperthermia and attempted to cool patient during the procedure. Postoperatively, the patient was transferred to the pediatric intensive care unit and treated for severe shock of unknown etiology. The patient further developed disseminated intravascular coagulation. The patient received supportive care and was started on ampicillin/sulbactam on postoperative day (POD) one which was changed to clindamycin, ciprofloxacin and tobramycin on POD two when blood cultures grew gram-negative bacilli. On POD three, cultures were identified as Y. enterocolitica and antibiotics were changed to tobramycin and cefotaxime based on susceptibility data. Sequelae of the shock included adult respiratory distress syndrome requiring intubation and a tracheostomy and multiple intracranial hemorrhagic infarcts with subsequent seizure disorder. Due to severe lower extremity ischemia, she required a bilateral below the knee amputation. The cultures of the snippets from the bags of blood transfused to the patient also grew Y. enterocolitica. This case illustrates the importance of considering transfusion related bacterial infections in patients receiving PRBCs. All patients in shock following any type of transfusion may require aggressive antibiotic therapy, until the diagnosis and etiology are known.
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PMID:Yersinia septic shock following an autologous transfusion in a pediatric patient. 1262 Feb 65

Paraplegia was reported after occlusion of the segmental vessels during anterior spinal surgery. The aim of this study was to investigate the effect of occlusion of the segmental vessels on the somatosensory-evoked potential (SEP) monitoring and analyze its potential risk for cord ischemia. Thirty-one patients with thoracic scoliosis underwent anterior spinal surgery. T5-T11 segmental vessels on the convexity were occluded with microvascular clamps at the point 2 cm from the intravertebra foramen. The SEPs were recorded 5 min before occlusion and 2, 7, 12 and 17 min after occlusion. The SEPs were analyzed with two indices i.e. P40 latency and P40 amplitude. All SEP waveforms recorded during the test were regular and recognizable. Compared to 5 min before occlusion, the P40 latencies at 2 min and 7 min after occlusion significantly increased 3.39% and 2.76% on an average, the P40 amplitudes at 2 min after occlusion significantly declined 26% (peak to peak) or 22% (peak to baseline) on an average (P<0.05). But the changes of SEPs were temporary. The SEPs began to restore at 12 min after occlusion and returned to the pre-occlusion level at 17 min after occlusion. No neurologic complications occurred in all patients after surgery. These results suggest that SEP is a possible indicator for ischemia of the spinal cord which is a dynamic course and cannot be considered an "all-or-none" phenomenon. Without the factors such as developmental deformities of the spinal cord, vascular variation and potential cord ischemia, occlusion of the segmental vessels would be safe during the anterior spinal surgery.
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PMID:Change pattern of somatosensory-evoked potentials after occlusion of segmental vessels: possible indicator for spinal cord ischemia. 1619 98

Somatosensory evoked potential (SEP) has been widely used for monitoring the abnormal nerve conduction in various diseases. In non-anesthetized patients, Abeta fibers are electrically stimulated during SEP measurements. In anesthesiological field, it is used as a short latency somatosensory potential (SSEP), because its latency and amplitude are relatively constant. To detect the conduction abnormality from the upper extremities to the brain, median nerve stimulation is used. For the detection of spinal cord abnormality during operation, posterior tibial nerve stimulation is often used. It is important to know the origin of the wave appearing in SSEP to find the lesion in the nervous system. SSEP has been used in scoliosis surgery, carotid endarterectomy, thoracoabodominal aortic surgery and cervical operations to detect brain and spinal ischemia. In an intensive care unit, it is used for the diagnosis of brain death or ischemia and other neuronal diseases such as Guillain-Barre syndrome and polyneuritis etc. In pain clinic, laser evoked potential (LEP) has been recently introduced for the analysis of the mechanisms of nerve and spinal cord diseases. Using the LEP, pain mechanism would be clarified. During SSEP measurements, it is necessary for the anesthesiologists, intensivists and pain clinicians to understand the effect of anesthetic drugs and hypothermia on SSEP.
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PMID:[Somatosensory evoked potential]. 1654 77

The authors report a case of man-in-the-barrel (MIB) syndrome occurring after an extensive revision involving thoracoilium instrumentation and fusion for iatrogenic and degenerative scoliosis, progressive kyphosis, and sagittal imbalance. Isolated brachial diplegia is a rare neurological finding often attributed to cerebral ischemia. It has not been previously reported in patients undergoing complex spine surgery. This 70-year-old woman, who had previously undergone T11-S1 fusion for lumbar stenosis and scoliosis, presented with increased difficulty walking and with back pain. She had junctional kyphosis and L5-S1 pseudarthrosis and required revision fusion extending from T-3 to the ilium. In the early postoperative period, she experienced a 30-minute episode of substantial hypotension. She developed delirium and isolated brachial diplegia, consistent with MIB syndrome. Multiple studies were performed to assess the origin of this brachial diplegia. There was no definitive radiological evidence of any causative lesion. After a few days, her cognitive function returned to normal and she regained the ability to move her arms. After several weeks of rehabilitation, she recovered completely. Man-in-the-barrel syndrome is a rare neurological entity. It can result from various mechanisms but most commonly seems to be related to ischemia and is potentially reversible.
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PMID:Man-in-the-barrel syndrome after thoracoilium fusion. 1903 49


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