A group of large randomized clinical studies investigated long term outcomes comparing anterior cervical discectomy and fusion (ACDF), to cervical disc replacement (CDR). They looked at measures including perceived neck function, general health, neurologic improvement and avoidance of future secondary surgical needs. All reported improvement in all outcomes with both CDR and ACDF, with no significant difference between to two procedures. However there have been studies showing that cervical disc replacement in the long term is more effective at preserving range of motion and decreasing degeneration at adjacent segments. In 2014, a cost effectiveness review that included measuring quality-adjusted life years (QALYs)for a five year follow-up found that CDR resulted in 2.84 QALYs while ACDF generated 2.81 QALYs. The cost-effectiveness ratio using these two measures was $35,976/QALYs for cervical disc replacement and $42,618/QALYs for anterior cervical discectomy and fusion. Ultimately, CDR was found to be less costly and also more effective when compared results in a 5 year follow-up span.