Introduction: Cervical spine zero-profile interbody cages are often used as an alternative to plate fusion. One perceived advantage for cage over plating is fusion segment isolation to better maintain overall alignment. This study compared radiographic parameters of alignment and others in patients who had ACDF with Stalif-C® PEEK Cages.

Methods: Review of 30 adult patients (mean age 52.9 ± 9.4; n=17 female) after multilevel anterior discectomy, partial corpectomy and Stalif-C® (Centinel Spine) interbody fusion cage for symptomatic DDD. Twenty-eight 2-level and two 3-level fusions were done. Existing medical records, A/P, lateral, and flexion and extension spine radiographs done pre-operative, intraoperative and post-operative were evaluated.

Results: Mean cervical lordosis change at average 3.5 month follow-up was 3.5º (range 0-9 º). The mean reduction middle vertebral height was 25.5% (range 2.4 to 46.7%). Mean subsidence was 1.9 ± 2.2 mm. One subject at 3 months had asymptomatic collapsed middle vertebra and also had highest reduction of the middle vertebrae. No significant complications were reported.

Conclusions: The collapse of the middle vertebra seen most likely was due to minimal remaining bone height and possible bone compromise due to placement of three anchoring screws. We believe caution should be used to avoid excessive bone removal when using zero-profile cages for these reasons. Due to supine patient positioning it can be difficult to achieve pre-operative anatomical alignment using anterior fusion plates. This review showed good post-operative preservation of pre-operative alignment overtime with zero-profile cage despite bone removal associated with multi-level partial corpectomies

Patient Care: Zero-profile cages in the cervical spine following ACDF may offer a viable alternative and advantage to plates in multi-level fusion for maintaining spine alignment.

Learning Objectives: Introduction to zero-profile cages for ACDF. Understand potential advantages, indications and disadvantages of zero-profile cages for ACFD. Learn about the potential benefits of maintaining anatomical alignment of the cervical spine following ACDF.

References: Matthew I. Stein, MDa, Aniruddh N. Nayak, MSb, Roger B. Gaskins, III, et al, Biomechanics of an integrated interbody device versus ACDF anterior locking plate in a single-level cervical spine fusion construct, The Spine Journal 14 (2014) 128–136 Aniruddh N. Nayak, MS, Matthew I. Stein, MD, Chris R. James, MD, et. al, Biomechanical analysis of an interbody cage with three integrated cancellous lag screws in a two-level cervical spine fusion construct: an in vitro study The Spine Journal 14 (2014) 3002–3010 Juan S. Uribe, Jaypal Reddy Sangala, Edward A.M. Duckworth, et al, Comparison between anterior cervical discectomy fusion and cervical corpectomy fusion using titanium cages for reconstruction: analysis of outcome and long-term follow-up Eur Spine J (2009) 18:654–662