Fusion rate following three- and four-level ACDF using allograft and segmental instrumentation: A radiographic study

Cervical spine degenerative pathologies remain one of the most common spinal conditions treated by spine surgeons worldwide. Surgery is recommended in all patients with symptomatic cervical spinal stenosis with either moderate to severe myelopathy, degeneration, or refractory radiculopathy. As the number of levels increases the potential for complications associated with anterior surgery can be significant, especially dysphagia and pseudarthrosis. The objective of this study was to analyze the fusion rate following three- or more level anterior cervical discectomy and fusion (ACDF). A retrospective review was performed analyzing patients who underwent three or more level ACDF. Fusion was evaluated using post-operative dynamic upright radiographs Relevant post-operative complications especially dysphagia requiring dietary modifications or placement of feeding tube was also noted. A total of 72 patients were included in the study. Of the 232 levels fused, pseudarthrosis occurred at 47 (14%) levels. Overall 45.8% of patients (33/72) had a pseudarthrosis. The incidence of pseudarthrosis was higher in patients with 4 level ACDF as compared to those with 3 level ACDF [56% (9/16) versus 42% (24/56)]. At last follow up, the number of patients that were symptomatic from their pseudarthrosis and required posterior spinal instrumentation was 8/72 (11.1%). Fusion rates in a large cohort of patients with three- and four-level ACDF performed utilizing allograft and segmental instrumentation is reported. The study demonstrates that 3-4 level, stand-alone anterior cervical arthrodeses result in at least one level of pseudarthrosis in almost half of patients, especially at the caudal level of the construct.