Authors: Zoe Teton; Barry Cheaney II, BS; Ahmed Raslan, MD; Khoi Than, MD (Portland, OR)

Introduction: Common interbody graft options for anterior cervical discectomy and fusion (ACDF) include: 1) structural allograft and 2) polyetheretherketone (PEEK). PEEK has gained popularity due to its radiolucency and elastic modulus similar to bone. Use of PEEK devices results in higher billing than allograft, which may drive selection. A previous study at our institution found a five-fold higher rate of pseudarthrosis with the use of PEEK devices as opposed to structural allograft in single-level ACDF. Here we follow up those findings with a report on the occurrence of pseudarthrosis of PEEK devices versus structural allograft in patients who underwent multi-level ACDF. Methods: We retrospectively reviewed 62 consecutive patients who underwent a multi-level ACDF, with at least 1 year of radiographic follow-up. Age, sex, body mass index (BMI), tobacco use, pseudarthrosis, and re-operation rate for pseudarthrosis were collected. Data was analyzed with a Pearson’s chi square test. Results: Of 62 patients, 31 had PEEK implants, and 31 had structural allograft. There were no differences between age, sex, or BMI in the two groups. There were 20/31 (65%) patients with PEEK implants demonstrating radiographic evidence of pseudarthrosis, compared to 6/31 (19%) patients with structural allograft (p < 0.001, OR 7.58; CI: 2.39-24.06). Four patients with PEEK implants required re-operation for pseudarthrosis (13%), compared to 0 patients with allograft (p = 0.014). There was no difference in tobacco use between the PEEK and allograft groups (p = 0.154). Conclusion: This study reinforces our previous findings on one-level ACDF outcomes, and suggests that the use of PEEK devices in multi-level ACDF also results in a high rate of radiographic pseudarthrosis and need for revision surgery. Surgeons should be aware of these results when deciding on interbody graft options, and reimbursement policies should reflect these discrepancies.