Several groups report their results of Anterior cervical discectomy and fusion (ACDF) using different techniques: allograft, autograft, cages with different designs and anterior cervical plates dynamic or not, with as most important outcome that the use of autograft is superior to allograft and that the postoperative neck-pain after surgery is relieved quicker after ACDF 2) 3) 4) 5).
Sagittal profiles of the spinal cord have been hypothesized to influence loads on spinal tissue and influence outcome after spinal surgery 7) 8). It is believed that ACDF surgery maintains sagittal alignment superiorly to ACD surgery, which should result in a better outcome after surgery and thus on the long term in less disability for the patients. Studies on sagittal alignment in the cervical spine have mainly focused on laminoplasty or arthroplasty 9) 10) showing a proper radiological position on the short term. Despite these radiological findings, clinically there has been no significant improvement in outcome on the longer term 11). Moreover, it has also been published that single-level procedures may lead to a local kyphosis, but do not influence the sagittal alignment as much as multi-level surgery 12).
Although, initially the postoperative outcome is good in more than 90% of the patients, the outcome score on the longer term gradually decreased as the follow up time after surgery increased in a subgroup of the patients. Patients who are doing well after surgery are found without a significant difference at all time points, however patients with moderate to severe complaints can be found increasingly in time after surgery. The increase of complaints at the time of the survey may be the result of ongoing degenerative effects. Only a few studies have been published focusing on a long follow-up period after cervical spine procedures compared to ACDF and therefore it is hard to address the ongoing degenerative effects in the cervical spine 13).