The importance of having class I data for ACDF outcomes


One-level anterior cervical discectomy and fusion has a 70% clinical success rate and 10% re-operation rate at two-year follow-up.

A meta-analysis has revealed that these are the true results obtained with this procedure and that the rate of success is lower than typically talked about in the spine surgery community, which is based on lower grade evidence.


Kenneth A Pettine told delegates at the North American Spine Society Annual Meeting in Orlando, USA, that anterior cervical discectomy and fusion is perceived by the spine surgeons to be one of the most efficacious of all spinal surgeries. “If asked, most spine surgeons would answer that a one-level anterior cervical discectomy and fusion is associated with a 95% fusion rate and a 95% excellent clinical result for neck and arm pain. However, the literature quoted is class III or class IV data, typically the work of a spine fellow or resident on a senior author’s surgical series,” he said.


Pettine clarified that the purpose of the meta-analysis was to determine the true or real clinical results of this procedure. “This is a meta-analysis of five studies with all class data available from FDA-IDE studies of anterior cervical discectomy and fusion. It resulted in a sample size comprising 1,154 single-level patients.”


The five studies included:


  • The BAK C cage and Affinity cage versus intervertebral allograft filled with local autologous bone versus intervertebral allograft without plating (two studies)
  • The Prestige artificial disc versus Atlantis anterior cervical plate
  • Pro-Disc artificial disc versus interbody fusion with cortical ring allograft bone and anterior plating system
  • Bryan artificial disc versus intervertebral allograft with plating


Results of re-operations at two years of anterior cervical fusion without plating were: 12% with BAK C; 17.5% for BAK C control; 9.2% for Affinity cage and 18.1% for Affinity cage control. “The overall re-operation rate for anterior cervical discectomy and fusion without plating is 12.7%,” Pettine told delegates.


With plating, the re-operation rates were 4.1% for Bryan control, 19.9% for Prestige control and 8.5% for ProDisc control. “There is an overall re-operation rate of 9.5% for anterior cervical discectomy and fusion with plating,” said Pettine.


The re-operations can be as a result of pseudoarthrosis, adjacent level degeneration or revision. In the meta-analysis, clinical success was defined as greater than 15 points improvement in neck disability index, no re-operation at index or adjacent level and no neurologic deterioration. Seventy per cent of patients achieved clinical success (range 67.88–72.7%).


“These results emphasise the importance of differentiating the validity of information gained from class I versus class III and IV data,” explained Pettine.