Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association
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We used a commercially available computer-assisted navigation system (StealthStation; Sofamor Danek, Memphis, TN, USA) in both an in-vitro and a clinical study performed in 1996-1998. The basic data used for navigation were preoperative computed tomography (CT) scan imaging data. The position of the probe or drill guide was superimposed in real-time on a monitor. ⋯ All screws correctly passed through the pedicles. There were no neurological complications after surgery. Using this guided surgery system, we achieved satisfactory results both in the laboratory and in a clinical setting.
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Comparative Study
Neovascularization of the outermost area of herniated lumbar intervertebral discs.
In 64 surgically treated herniated lumbar intervertebral discs, we performed histopathological studies of neovascularization in the outermost layer of the herniated mass in various types of hernia. We obtained specimens separately from the capsule tissue covering the herniated mass and the inner tip tissue of the herniated mass for comparison. Histologically, in most cases, the capsule tissue was the outermost layer of the annulus fibrosus or posterior longitudinal ligament, and the inner tip tissue was the nucleus pulposus. ⋯ When the intervertebral disc herniates, new blood vessels proliferate in the capsule of the hernial tissue. At the stage when the hernial capsule tissue is still present, these vessels were observed to have difficulty reaching the inner tip portion. These findings suggest that when the nucleus pulposus portion of the herniated mass perforates the posterior longitudinal ligament, it may be subject to a stronger neovascularization reaction.
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Displaced fractures of the sacrum are often associated with mechanical instability and neurologic deficits that cause late musculoskeletal problems and pain. We describe the radiologic and neurologic characteristics of 12 displaced fractures of the sacrum, (in 5 men and 7 women; age at injury, 17-61 years) as well as the management and results. Seven patients had unilateral longitudinal fractures (ULF), and 5 had bilateral longitudinal fractures (BLF) with a transverse fracture. ⋯ Two patients did not recover neurologically; 1 patient with ULF had undergone late decompression for chronic radiculopathy and the other, with BLF, had had complete paralysis pre-operatively. Five patients with incomplete paralysis recovered both sensory and motor function. If a patient with a sacral fracture has instability, operative treatment with anatomical reduction is preferred.