This study aims to assess if there is an evident correlation between fusion length and rehabilitation success after trauma to the cervical spine that could potentially be used to predict functional outcomes. This monocentric study was conducted in the Spinal-Cord-Injury center of the Berufsgenossenschaftliches Klinikum Hamburg. Data sets of 199 patients from the Spinal-Cord-Injury center admitted between the beginning of 2003 and the end of 2018 were subjected to statistical analyses. The Spinal Cord Independence Measure II (SCIM II) difference between admission and discharge was chosen as the primary outcome variable of a multiple linear regression analysis, including several other variables. The length of fusion, SCIM at admission and the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) values at admission could be identified as significant predictors. The cervical fusion length could be identified as an independent predictor of the functional outcome within our model. This correlation most likely mediates for the range of motion as well as partly for injury severity. This is much harder to evaluate in a newly admitted rehabilitation patient than a single numerical value that represents its rehabilitative implications, such as fusion length. Together with an initial assessment of the SCIM and ISNCSCI, it provides a solid basis for outcome prediction.