Der Orthopäde
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Comparative Study
[Placement of pedicle screws using different navigation systems. A laboratory trial with 12 spinal preparations].
A well-known problem occurring with thoracolumbar spondylodesis is the perforation of pedicle screws through the pedicle wall. It occurs in up to 40% of the implanted screws. To reduce this problem, computed tomography (CT)-based navigation systems have been introduced, which allow the surgeon multidimensional control of the screw position in virtual reality and real time during insertion. ⋯ We inserted 77 pedicle screws in human lumbar cadaveric spine specimens either without navigation, with CT-based navigation, or with fluoroscopy-based navigation. In the critical sizes of pedicles between 6.5 and 9 mm, we found the best results with CT-based navigation, but there was no significant difference between the three methods. The minimal pedicle and the screw diameters should be reported in every study on pedicle screw misplacement and spine navigation since they represent the most important factor in pedicle wall perforations.
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There is a rapid increase of computer-assisted surgery (CAS) in the spine for insertion of pedicle screws. In contrast to the traditional technique using fluoroscopy, CT is the primary source for surgical navigation systems. ⋯ In experienced hands open pedicle screw insertion in the thoracic and lumbar spine using fluoroscopy-control requires a fifteen times lower radiation dose than do CT scans necessary for computer-assisted surgery. Regarding the published small percentage of neurological complications in traditional screw insertion technique the use of computer-assisted surgery in pedicle screw insertion using CT scan should be limited to carefully chosen indications. The development of navigation systems based on other data sources than CT should be encouraged.
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Subsequent to clinical and radiologic examination, ultrasonography is an important diagnostic method in knee and foot trauma, especially to assess pathologic conditions of the periarticular soft tissue. The main indications for ultrasonographic assessment of the knee region are fluid conglomerations, injuries of tendons, ligaments, and muscles, and vascular diagnosis. ⋯ Fractures involve the base of the fifth metatarsal, navicular and sesamoid bones, and epiphysiolysis. Rare indications are the search for free articular bodies and free air and the depiction of cartilaginous lesions and fractures of the knee region.
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A total of 329 children with hip pain were examined by ultrasound, which indicated transient synovitis (n = 161), rheumatoid arthritis (n = 16), tuberculoid arthritis (n = 3), septic arthritis (n = 16), Legg-Calvé-Perthes disease (n = 102), and slipped capital femoral epiphysis (n = 31). Using the standard planes described by DEGUM and DGOOC, it is possible to analyze the joint capsule, the surface of the femoral head, and the periarticular structures. ⋯ Because capsular distension exhibits no significant differences in the various diseases, differentiation is not possible with ultrasound in the absence of osseous abnormalities. In cases with both capsular distension and osseous abnormalities, ultrasound usually allows a differentiation between slipped capital femoral epiphysis and Perthes disease as well as septic and unspecific arthritis.
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Case Reports Comparative Study
[Low-grade central osteosarcoma . 3 case reports].
Low-grade central osteosarcoma is a well-differentiated subtype of osteosarcoma, which is often confused with benign lesions. Males and females were affected about equally in our study. ⋯ Excision of the tumor almost invariably led to recurrences. Wide resection was almost never followed by recurrence and seems to be the treatment of choice for this very rare variant of osteosarcoma.