Добавил:
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Книги по МРТ КТ на английском языке / Atlas of Postsurgical Neuroradiology - Imaging of the Brain Spine Head and Neck 2017.pdf
Скачиваний:
6
Добавлен:
05.10.2023
Размер:
65.07 Mб
Скачать

11  Imaging of Postoperative Spine

579

 

 

11.4.4\ Dynamic Facet Replacement

11.4.4.1\ Discussion

Facet replacement devices have been created in an attempt to replace only the diseased elements in patients with facet arthropathy and spinal ­stenosis while maintaining normal or near-nor- mal biomechanics of the spine. The total posterior facet replacement and dynamic motion segment stabilization system (TOPS) includes two titanium endplates on either side of a layer of

a

radiolucent, compressible polycarbonate urethane. This polycarbonate acts as a shock absorber and allows for motion between the endplates, providing rotation, bending, flexion, and extension to the patient. The device is held in place by pedicle screws. On imaging, the screws and plates are radiopaque, and the central polycarbonate urethane layer is radiolucent (Fig. 11.88). Other devices used for facet replacement include TFAS (Total Facet Arthroplasty System) and Zyre.

b

Fig. 11.88  Dynamic facet replacement device. Frontal (a) and lateral (b) radiographs show total posterior facet replacement and dynamic motion segment stabilization system at L4–L5