Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association
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We describe two cases of combined fractures of the odontoid process and upper thoracic spine that have not been previously reported. The first patient, a 21-year-old man, sustained an odontoid process fracture with posterior displacement and a fracture-dislocation injury at T4/5 in a motorcycle accident. The second patient, a 66-year-old woman, fell from a cliff and sustained an odontoid process fracture with posterior displacement and a bursting fracture at T3 and T4 with rotation. ⋯ The second patient escaped neurological deficit. Both underwent anterior screw fixation of the odontoid process and posterior fusion of the upper thoracic spine. In both cases the cervical spine seemed to be in hyperextension, and the upper thoracic spine experienced sudden flexion and rotation forces.
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The risk of accelerating the degeneration of adjacent disc levels after lumbar spinal fusion is a controversial issue. A finite element model consisting of L1 to L5 lumbar spines was used to assess the effect on adjacent disc level after lumbar spinal fusion. We compared intact, L4/5 posterior interbody fusion (PLF), and L4/5 posterior lumbar interbody fusion (PLIF) models. ⋯ The Tresca stress of the annulus fibrosus from the posterior surface of the disc to the neural foramen adjacent to the fusion level was higher than that on other nonfusion intervertebral levels; and it was higher under conditions of flexion moment loading plus compression loading [107% (1.48 PMa) in the PLF model and 112% (1.54 Mpa) in the PLIF model] than in the intact model. These findings demonstrate that with lumbar fusion, stresses on the vertebral end-plate and the annulus fibrosus were high adjacent to the fusion level; furthermore, stresses were higher in the PLIF model than in the PLF model. These results suggested that lumbar spinal fusion might bring with it a risk of damage to the annulus fibrosus and the vertebral end-plate adjacent to the fusion level.
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Case Reports
Computed tomography-guided screw fixation of a sacroiliac joint dislocation fracture: a case report.
A 19-year-old woman sustained a vertical shear type pelvic fracture. Sacroiliac fixation using computed tomography (CT)-guided cannulated screws was performed for a left sacroiliac dislocation fracture, and a satisfactory result was obtained over time. ⋯ Advantages of CT-guided sacroiliac screw fixation include precise evaluation of the degree of reduction and absence of nerve and vascular damage during the time the screw is inserted into the sacral body. This procedure is a useful, safe method owing to its minimal invasiveness in patients with unstable pelvic fractures that are reducible by manual manipulation or traction.
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We treated 16 patients with equinus contracture using the Ilizarov method without open soft tissue release. No hinge was used in seven patients; instead, their ankle joint was used as the hinge (natural hinge; unconstrained construct). In the remaining nine patients, medial and lateral hinges connecting the tibial and foot rings were placed at the center of the talar dome (rotating hinge; constrained construction). ⋯ The natural hinge system is therefore the method of choice for treating equinus contracture because it is less invasive and simpler. However, particular care is needed during correction to avoid complications such as anterior subluxation of the talus and joint space narrowing. When complications do occur, intervention should be immediate.
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Comparative Study
Biomechanical evaluation of kyphoplasty and vertebroplasty with calcium phosphate cement in a simulated osteoporotic compression fracture.
Kyphoplasty and vertebroplasty with polymethylmethacrylate (PMMA) have been used for the treatment of osteoporotic vertebral compression fractures. We performed kyphoplasty and vertebroplasty with alpha-tricalcium phosphate cement (CPC) and PMMA to compare the biomechanical properties. Thirty osteoporotic vertebrae were harvested from nine embalmed cadavers. ⋯ In the vertebroplasty groups, the augmented stiffness was not significantly different from the initial stiffness. There was no significant difference between the two bone cements for either procedure when cement volume and restoration of anterior height were assessed. We concluded that kyphoplasty and vertebroplasty with CPC were viable treatment alternatives to PMMA for osteoporotic vertebral compression fractures.