Comparison of Radiological and Clinical Outcomes between Expandable and Non-expandable Cages Following Cervical Corpectomy: A Systematic Review and Meta-analysis

Anterior cervical corpectomy and fusion is considered the mainstay of surgical treatment in cervical pathology. Expandable and non-expandable cages are preferred over autogenous bone graft because of donor-related morbidity. However, the choice of the cage type remains a debatable topic as studies report conflicting results. Thus, we evaluated the outcomes of expandable and non-expandable cages following cervical corpectomy. Studies were searched in various electronic databases (MEDLINE, PubMed, EMBASE, CINAHL, Scopus, and Cochrane) between 2011 and 2021. Forest plot was made to compare the radiological and clinical outcomes between expandable and non-expandable cages following cervical corpectomy. Altogether, 26 studies (1,170 patients) were included in the meta-analysis. The mean change in segmental angle was significantly greater in the expandable cage group than in the non-expandable cage group (6.7° vs. 3.0°, p<0.001). The mean subsidence rate was lower in the expandable cage group (6% vs. 41%, p<0.001). The mean fusion rate was lower (93% vs. 98%, p=0.06) and the mean displacement rate was significantly higher in the expandable cage group (29% vs. 5%, p<0.05). The mean reoperation rate was higher in the expandable cage group (16% vs. 2%, p>0.05). The improvement in segmental angle is better with expandable cages. Higher subsidence is a major problem with non-expandable cages, but it seems to be beneficial as evidenced by the high fusion rate and minimal effect on clinical outcome in patients with this cage.