Background:

Expandable cages have been increasingly used in cervical and lumbar reconstructions, however there is a paucity in the literature on how they compare to traditional non-expandable cages in the cervical spine. We present a systematic review and meta-analysis here, comparing the clinical and radiological outcomes of expandable versus non-expandable corpectomy cage use in the cervical spine.

Methods:

A database search identified studies detailing the outcomes of expandable and non- expandable titanium cage use in the cervical spine. These were screened using the PRISMA protocol. Fixed and random effects models were used with a 95% confidence interval. Two analyses were carried out for each outcome, one including all studies, the other including only studies reporting on exclusively 1-level and 2-level cases.

Results:

Forty-one studies were included. The mean change in segmental lordosis was significantly greater in expandable cages (all: 6.72 vs. 3.69°; p<0.001), (1-level and 2-level: 6.81° vs. 4.31°; p<0.001). The mean change in cervical lordosis was also significantly greater in expandable cages (all: 5.71° vs. 3.11°; p=0.027), (1-level and 2-level: 5.71° vs. 2.07°; p=0.002). No significant difference was found between the complication rates (all: p=0.43), (1-level and 2-level: p=0.94), however the proportion of revisions was significantly greater in expandable cages (all: 0.06 vs. 0.02; p=0.03) (1-level and 2-level: 0.08 vs. 0.01; p=0.017).

Conclusion:

The use of expandable cages may carry a modest improvement in radiological outcomes compared to non-expandable cages in the cervical spine; however, they may also lead to a higher rate of revisions based on our analyses.