Comparison of revision surgery for pseudarthrosis with or without adjacent segment disease after anterior cervical discectomy and fusion

BACKGROUND: Patients with a pseudarthrosis after anterior cervical discectomy and fusion (ACDF) may have concurrent adjacent segment disease (ASD). Although prior studies have shown posterior cervical decompression and fusion (PCDF) is effective in repairing pseudarthrosis, improvement in patient reported outcomes (PROs) has been marginal. The aim of this study is to evaluate the effectiveness of PCDF in achieving symptom relief in patients with pseudarthrosis after ACDF and whether that is altered by the additional treatment of ASD. METHODS: Thirty-two patients with pseudarthrosis were compared with 31 patients with pseudarthrosis and concurrent ASD after ACDF who underwent revision PCDF with a minimum 1-year follow-up. Primary outcomes measures included the neck disability index (NDI), and numerical rating scale (NRS) scores for neck and arm pain. Secondary measures included estimated blood loss (EBL), operating room (OR) time, and length of stay. RESULTS: Demographics between cohorts were similar, however there was a significantly higher mean body mass index (BMI) in the group with concurrent ASD (32.23 vs. 27.76, p=.007). Patients with concurrent ASD had more levels fused during PCDF (3.7 vs. 1.9, p<.001), greater EBL (165 cc vs. 106 cc, p=.054), and longer OR time (256 minutes vs. 202 minutes, p<.000). Preoperative PROs for NDI (56.7 vs. 56.5, p=.954), NRS arm pain (5.9 vs. 5.7, p=.758), and NRS neck pain (6.6 vs. 6.8, p=.726) were similar in both cohorts. At 12 months patients with concurrent ASD experienced a slightly greater, but not statistically significant, improvement in PROs (Δ NDI 4.40 vs. -1.44, Δ NRS neck pain 1.17 vs. 0.42, Δ NRS arm pain 1.28 vs. 0.10, p=.107). CONCLUSIONS: PCDF is a standard procedure for treatment of pseudarthrosis following ACDF, however improvements in PROs are marginal. Slightly greater improvements were seen in patients whose indication for surgery also included concurrent ASD, rather than a diagnosis of pseudarthrosis alone.