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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fracture of the distraction rod is one of the complications following operative treatment of scoliosis by the device of Harrington. It is reported to occur in about 7% of cases. We found this complication twice in our own number of 41 patients during a follow up period of 1 to 4 years. The rods had broken 18 and 23 months after operation, but we never saw a breakage in the 1st postoperative year during the time of cast fixation. The fracture surfaces of each rod were examined under the scanning electron microscope. In one case a fatigue fracture with two beginnings at the opposite sides of the rod was found in combination with a forced fracture in the middle. The number of alterations of load from the beginning of the fracture to the complete breakage was about 10,000. The X-ray showed a loss of correction in the curve of 20 degrees with a pseudoarthrosis visible in the fusion. In the other case a typical pure fatigue fracture was seen 23 months after the operation with 18,000 alterations of load. The X-ray showed only a slight loss of correction of less than 5 degrees and no pseudoarthrosis was visable, neither in the X-ray nor in the operative exploration of the fusion. The breakage of the distraction rod results not only from a pseudoarthrosis but also from other explained facts of the procedure. Further treatment depends on a proven pseudoarthrosis.
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PMID:Damage analysis of the Harrington rod fracture after scoliosis operation. 52 22

While midair collisions between aircraft are extremely rare occurrences, 'near midair' incidents are more common. The present study sought to evaluate the gains in conspicuity that might be realized if flashing or colour were added as redundant cues to indicate the presence of unexpected, non-tracked aircraft entering controlled airspace, and to examine the extent to which increased taskload and fatigue might influence the expected gains. Sixty-four subjects monitored a simulated air traffic control task over a 2 h period for possible conflict situations (their primary task) under either high or low primary taskload conditions. They also monitored for occasional intrusions by light aircraft identifiable on the basis of target shape alone or with colour and/or flashing added as redundant cues. Flashing as a redundant cue was found to be superior to colour in all aspects tested; unlike colour, detection of flashing targets was unaffected by screen location and by changes in primary taskload. Flashing was also least affected by monitoring fatigue. It was concluded that the superiority of flashing over colour in attracting attention to objects in a display must be weighed against its possible potential for distraction. A practical means of accomplishing this in operational situations is through the use of touch sensitive displays to both acknowledge/confirm target location and to deactivate flashing.
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PMID:Effects of monitoring under high and low taskload on detection of flashing and coloured radar targets. 193 83

The authors have evaluated a complex of 34 femurs prolongated in the period 1978-1988 by means of Wagner (26), Ilizarov (5) or bisegmental external fixation device of their own design (3). The whole group comprised 13 boys and 21 girls in the age group ranging from 6.5 to 17.25 years of age. In 13 cases the shortening of the extremity was congenital, in 21 cases it was of secondary nature. All usual data were observed and the quality of healing in the distraction gap was assessed by means of x-ray check up. The average shortening in the above mentioned group of patients ranged from 40 to 50 mm, the average prolongation of the bone was 40 mm. Subsequent osteosynthesis by means of a plate was carried out and bone grafts were applied in one third of the children. The healing of the bone gap was more rapid in children up to 12 years of age. The differentiation of medullary canal and corticalis occurred on average 15 months after operation and the normal shape of the bone was restored 22 months after operation. Full body weight bearing was allowed in case of the Wagner device on average after 11 months, in case of the Ilizarov's device after 14.5 months, but in case of the bisegmental device as early as 6 months after the accomplishment of the prolongation phases. The complications during the prolongation comprised angulation of the bone (3), dislocation of patella (2), reduction of the range of motion of the knee (4). The complications after the removal of the device included traumatic fracture (4), fatigue fracture (3), angulation of femur (1). On the basis of the analysis of the material the authors recommend in case of these patients to concentrate attention in the following direction: 1. In cases where the shortening is evident the operation should not be delayed and the femur should be prolonged as early as until 12th year of age of the patient. 2. The prolongation should be performed only by means of a stable external fixation device. Ilizarov's device is not in this case desirable. Where the size of the femur is suitable it is recommended to apply the bisegmental device. 3. Osteotomy should be longer and oblique and the contact of bone fragments should be maintained. 4. The prolongation should start no sooner than 7-10 days after operation to enable the bone callus to be prolongated to get organized.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Analysis of the results of femoral lengthening in 34 children and adolescents]. 227 6

The performance characteristics of Harrington-Moe distraction rods, paired wired Luque rods and Drummond's system were evaluated and compared when subjected to nondestructive cyclic, multidirectional biomechanical testing. Twelve fresh, frozen swine spines with intact facet joints and anterior and posterior ligamentous complexes were instrumented and tested in a specially designed pneumatic testing machine. The instrumented spines were subjected to 207 kN/m2 compression and 49 N-m torsion. Each spine was cycled 28,000 times at 1 cycle per second. Linear and angular displacements were determined by digitizing photographs and video tapes made during testing. A computer program developed and refined for the project was used to complete the data analysis. Approximately 540 items of angular and linear displacement data were collected for each spine. Inspection of the spines after cyclic, multidirectional testing revealed no change in their osteoligamentous integrity compared with pre-testing. Pre- and post-testing radiographs showed no evidence of osseous failure, hook dislodgement or wire breakage. Erosion of laminal bone at the Harrington hook attachment sites was observed. Displacement of the Harrington hooks was seen during off-axis compression-torsion testing. Fretting and deposit of metal wear debris occurred between the sublaminal wires and "L" rods. There was no evidence of loosening of either the Drummond or Luque implants or fatigue failure of any component. Analysis of the linear and angular displacement data showed that the Luque and Drummond instrumented spines displaced less in axial compression, off-axis compression and off-axis compression-torsion than the single Harrington-Moe distraction rod.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Multiaxis cyclic biomechanical testing of Harrington, Luque, and Drummond implants. 232 94

Ten in-vivo failed spinal instrumentation systems, i.e. six Harrington distraction rods with sublaminar hooks, one Harrington distraction rod with segmental wiring and three Luque rods with sublaminar wires, were fractographically analysed. In both Harrington and Luque rods corrosion fatigue was the predominant mechanism resulting in the failure. Five Harrington rods fractured at the first ratchet junction; fractures of the Luque rods were initiated by fretting of sublaminar wire with the rod surface in the presence of spinal non-union. Fretting and crevice corrosion were found to play an important role in compromising the segmental spinal instrumentation. The susceptibility of the 316 L CW austenitic stainless steel to pitting and relative resistance to crevice corrosion were measured by cyclic anodic polarization tests. The oxide inclusions have been found to play a significant role in the pitting of the alloy.
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PMID:Role of corrosion in Harrington and Luque rods failure. 270 97

We have recently demonstrated that humans report heat stimuli as less painful when presented concurrently with a second noxious stimulus applied to another part of the body. Previous neurophysiological studies have shown that similar heterotopically applied noxious stimuli selectively and completely inhibit the activity of wide-dynamic-range (WDR) neurons in the dorsal horn - a phenomenon termed diffuse noxious inhibitory controls (DNICs). Taken together, these 2 lines of evidence suggest that activation of WDR cells may be necessary for normal perception of pain. Recent studies in the behaving monkey have additionally shown that WDR neurons respond to small changes in noxious heat stimuli better than do high threshold neurons, thus indicating a more specific role for WDR neurons in sensory-discriminative aspects of pain perception. If DNICs do indeed selectively and completely inhibit the activity of WDR neurons, then a heterotopically applied noxious stimulus should selectively interfere with a subject's ability to discriminate noxious stimuli. This hypothesis was tested using a noxious heat discrimination task and a cold water (5 degrees C) diffuse noxious stimulus. We found that the ability to detect small changes (0.4-0.8 degrees C) in painful heat stimuli applied to the face decreases when the person's hand is submerged in painfully cold water (P = 0.005) and that this effect persists, to a lesser extent, after the hand is removed from water. Control tasks, using visual stimuli, demonstrated that the modulation of nociceptive discrimination was not a generalized effect on sensory perception; other control measures indicated that the results could not be attributed to distraction, fatigue or changes in response bias.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of diffuse noxious inhibitory controls (DNICs) on the sensory-discriminative dimension of pain perception. 291 3

Fourteen patients with degenerative spondylolisthesis and three patients with degenerative scoliosis, all of whom experienced low-back pain, lumbar radiculopathy, and/or intermittent claudication were treated with posterolateral fusion and correction of deformities using a new instrumentation system. This new spinal fixation system combines the advantages of a rod for scoliotic deformities and a plate for sagittal plane disorders. The combination rod-plates can apply multiple forces to facilitate correction of complex deformities as well as enable indirect neurologic decompression. The system allows segmental rigid fixation via transpedicular screws that is limited only to the abnormal vertebral levels to preserve the maximum number of uninvolved lumbar motion segments. The physiologic lumbar lordotic curvature is also preserved. The minimum follow-up period was 1 year. Satisfactory results were obtained in 15 patients (88%). No intraoperative complications occurred. Screw fatigue occurred in two patients at 1-year follow-up examination with no sequelae. The scoliotic and spondylolisthetic deformities were reduced significantly in all patients. This method appears to assist in reducing pathologic motion and deformities that contribute to low-back pain. Compression on neural structures is relieved by thorough decompression and distraction; spinal canal anatomy is also restored.
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PMID:Degenerative spondylolisthesis and degenerative scoliosis treated with a combination segmental rod-plate and transpedicular screw instrumentation system: a preliminary report. 298 Feb 52

Fifty-four patients were treated by a standardized single stage anterior opening wedge and a posterior closing extension wedge osteotomy for back pain associated with postoperative loss of lumbar lordosis (iatrogenic flat back syndrome). Presenting complaints were fatigue, pain and a stooped posture. Etiological factors were, in descending order of frequency, distraction instrumentation with the lower end at the L5 or S1 vertebra, thoracolumbar junction kyphosis greater than 15 degrees, especially if associated with a hypokyphotic thoracic spine, and degenerative changes above and below a previous fusion. Kostuik-Harrington instrumentation was used anteriorly for the opening wedge and Dwyer cables and screws together with a midline plate were used posteriorly for the closing extension osteotomy. Malunion occurred in three patients, one requiring recorrection. Pain relief occurred in 48 (90%). Neurological complications occurred in two patients, one with permanent deficient. Follow-up averaged 4 years. Average preosteotomy lordosis L1-S1 was 21.5 degrees and was restored to 49 degrees (equal to the lordosis before the initial surgery) for an average correction of 29 degrees, (range 24 degrees to 63 degrees). Prevention of this complication can be accomplished by maintaining normal lordosis at the time of initial surgery.
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PMID:Combined single stage anterior and posterior osteotomy for correction of iatrogenic lumbar kyphosis. 338 11

Fifty patients (14-55 years of age) with unstable thoracolumbar fractures were studied: 24 patients treated conservatively 1971-1977 and 26 patients treated surgically with Harrington instrumentation 1977-1981. The treatment groups were comparable in all respects. Radiologic evaluation showed that Harrington distraction rods restored the fractured vertebra almost to its original shape, and the gibbus and scoliosis were significantly reduced. However, at the follow-up examination at least 2 years after the injury, the gibbus angle had recurred almost to the value at admission in patients with the rods removed. The conservatively treated patients showed a continuous increase of the gibbus angle and of the anterior and central vertebral compression. At the follow-up evaluation, all fractures in both treatment groups were healed. There was no difference between the treatment groups regarding neurologic improvement. Thirteen of 14 patients with severe or moderate paraparesis considerably improved their neurological status. A rehabilitation index with special reference to paraparetic patients showed no difference between the treatment groups already three months after the injury. Thoracolumbar fatigue, thoracolumbar pain and stiffness, skin problems, and pain at direct pressure at the fracture site occurred equally in the conservative and Harrington groups. The overall complications were few. The aseptic intermittent catheterization method introduced in 1977 considerably diminished the frequency of upper urinary tract infections. The treatment with open reduction, fusion, and stabilization with Harrington rods considerably reduced the immobilization and hospitalization times. The average immobilization time was reduced from 67 to 18 days. The hospitalization time in neurologically intact patients was reduced from 80 to 30 days.
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PMID:Unstable thoracolumbar fractures. A comparative clinical study of conservative treatment and Harrington instrumentation. 400 35

A retrospective review of 206 consecutive thoracic and lumbar fusions revealed a variety of surgical procedures performed for instability and malalignment after severe trauma. Stabilization procedures included insertion of 103 Harrington distraction and 15 Harrington compression rods, 84 Weiss spings, six Luque rods, and 10 miscellaneous plates and wires as single or multiple devices in combination with anterior and/or posterior fusions. Complications of surgical fusion included nine unhooked rods, six fatigue fractures of rods and springs, five overdistractions of vertebrae, four cases of severe kyphosis, and two failures of reduction. A meaningful postoperative radiologic evaluation can be accomplished only when indications for surgical techniques, their radiologic appearance, and possible complications are known.
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PMID:Thoracic and lumbar spine fusion: postoperative radiologic evaluation. 660 37


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