A spinal implant system for correcting spinal deformities and abnormalities includes an elongated spinal rod configured to be implanted adjacent the spinal column and spanning across several vertebral levels. A number of fixation elements, such as spinal hooks, are provided for engaging vertebrae at...http://www.google.es/patents/US5562662?utm_source=gb-gplus-sharePatente US5562662 - Spinal fixation system and method
