Stand-Alone Interbody Devices in the Treatment of Cervical Spine Disease
Authors: Happ Christopher , Guyer Richard , Zigler Jack , Ohnmeiss Donna , Blumenthal Scott 
Published: May 2015

Introduction

Anterior cervical fusion (ACF) with anterior plating is generally considered the surgical standard of care for treating of cervical disc disease. Striving to improve or maintain outcomes while reducing complication risks led to “stand-alone” ACF implants with integrated cage and screw systems eliminating the use of traditional plates. Although a variety of such devices have been introduced, there is little published information available on their outcomes. The purpose of this study was to evaluate the results from stand-alone ACF and to compare results with existing data for ACF using allograft and an anterior cervical plate.

Methods

Data were collected for all patients who were a minimum of 12 months postoperative following stand-alone ACF at 1 or 2 levels, and who had no previous ACF ( n = 59). Data collected included demographics, blood loss, visual analog scales (VAS) assessing neck and arm pain, neck disability index (NDI), and reoperations. Mailings and telephone calls were made to patients not recently seen in clinic to collect outcome data. To put the stand-alone ACF results into context, results were compared with a group of patients who served as controls in randomized studies comparing total disc replacement to ACF performed using allograft and an anterior plate ( n = 57). The mean follow-up in both groups was approximately 22 months. The mean age in the stand-alone group was greater than in the allograft/plate group (50.7 vs. 42.4 years; p < 0.05) as was the percentage of patients undergoing two-level fusion (33.9% vs. 17.5%; p < 0.05).

Results

Both the groups had statistically significant improvement in mean neck and arm pain VAS scores ( p < 0.01, Fig. 1 ) with no differences between the groups ( p > 0.05). In both groups, mean NDI scores improved significantly ( p < 0.01). Regression analysis was performed to compare the percent change in NDI scores in the two groups to adjust for the preoperative NDI score being greater in the allograft/plate group and the differences in age and number of levels operated. The regression results found no significant difference but a trend favoring allograft/plate (0.05 <  p < 0.10). There was a trend toward a lower reoperation rate in the stand-alone fusion group compared with the anterior plate group (0.05 <  p < 0.10). Of the 59 patients, 3 patients (5.1%) in the stand-alone group underwent reoperation, including two at adjacent segments and the other reoperation was performed at a different center and appeared to have involved removal of the stand-alone device with fusion of the segment. In the anterior plate comparison group, 8 of 57 patients (14.0%) underwent subsequent surgery (four for pseudoarthrosis and four at an adjacent segment). [Figure: see text]

Discussion

The stand-alone ACF group had outcomes similar to the allograft and anterior plate group, with both groups experiencing significant improvement in neck and arm pain scales and NDI (although trend for greater improvement in allograft/plate group) and a trend toward a lower reoperation rate after the stand-alone procedure. The results suggest that stand-alone ACF may be a viable alternative to allograft/plate procedures.