The primary endpoint is the successful fusion rate in radiographic assessment at more than 2 years.
This is a single center, hybrid retrospective and prospective (ambispective) study to evaluate the safety and efficacy of the Facet Fixation implant.~The main objective is to evaluate the efficacy of the Facet Fixation implant compared with pedicle screw fixation to determine successful fusion in radiographic assessment at more than two years. Fusion is mainly defined as any sign of bony fusion between the facet joints or transverse processes when viewing the postoperative CT-scan at over 2 years.