Is stand alone PEEK cage the gold standard in multilevel anterior cervical discectomy and fusion (ACDF)? Results of a minimum 1-year follow up

Highlights

• At multilevel, fusion rate of stand-alone ACDF is not lower than anterior plating ACDF.

• Subsidence is an inevitable phenomenon of stand-alone cages.

• Subsidence was not related to fusion failure and clinical outcome in our study.

Abstract

Introduction

This study was designed to evaluate the clinical and radiologic results of stand-alone synthetic polyetheretherketone (PEEK) cages for two- or three-level anterior cervical discectomy and fusion (ACDF), with a focus on subsidence.

Materials and methods

We retrospectively reviewed a total of 68 patients who underwent two- or three-level ACDF with a stand-alone PEEK cage between April 2005 and August 2016. Radiologic parameters were assessed on lateral radiographs, and fusion was assessed on computed tomography scans. For the evaluation of clinical outcomes, visual analogue scale, neck disability index, and modified Japanese Orthopedic Association scores were measured.

Results

Among the total of 68 patients with a total of 144 segments, ACDF at two and three levels was performed in 60 and 8 patients, respectively, with a mean follow-up duration of 27.6 months. The overall fusion rate was 81.3% (117 of 144 segments), and subsidence occurred in 63 segments (43.8%) at the last follow-up. There was no statistically significant difference between the subsidence group and the nonsubsidence group in terms of fusion rate, radiologic outcomes, and clinical outcomes (p > .05).

Conclusion

Subsidence might be an inevitable course and only a radiologic phenomenon with no effect on the clinical and radiologic outcomes of the use of stand-alone cages.

Introduction

Anterior cervical discectomy and fusion (ACDF) has been considered a standard procedure for the treatment of degenerative cervical diseases associated with radiculopathy or myelopathy. Although many modifications and surgical techniques for ACDF have been performed in the last decades, the success of the procedure undoubtedly depends on proper decompression of neural structures and solid bony fusion with maintenance of cervical sagittal alignment.

Anterior plating may provide immediate stability, a high fusion rate, and maintenance of cervical lordosis [1], [2]. However, it is associated with plate-related complications such as loosening or pullout of screws, esophageal injury, dysphagia, and paralysis of the recurrent laryngeal nerve [3], [4].

To prevent plate-related complications, the use of stand-alone cages has been advocated. This method is effective for restoring the intervertebral disc height and lordosis, and providing load-bearing support to the anterior column; however, it has a relatively higher probability of subsidence than anterior plating [5].

However, many reports examining subsidence did not assess the correlation between subsidence and the clinical outcomes (including fusion rate) of single-level ACDF [6], [7].

Although many techniques for single-level ACDF have yielded successful fusion rates with good clinical outcomes, the fusion rate declines as the number of affected levels in multilevel ACDF increases [8], [9]. Therefore, anterior plating, which could provide postoperative stability and decrease the micro-movement of fusion segments, has been widely used for multilevel ACDF [10]. However, the rate of plate-related complications after multilevel anterior plating ACDF has reached 24%, and Topuz et al. and Demircan et al. reported that the fusion rate was comparable with multilevel stand-alone ACDF [1], [11], [12].

The purpose of this study was to establish the usefulness of stand-alone synthetic polyetheretherketone (PEEK) cages for two- or three-level ACDF, by evaluating the clinical and radiologic results.