Introduction: The Forgotten Joint Score (FJS), used in joint arthroplasty, has low ceiling effects and high discriminatory capacity. No equivalent exists in spine surgery. The FJS would be useful in evaluating outcomes of cervical disc replacement (CDR) vs. anterior cervical discectomy and fusion (ACDF). CDR is relatively novel and offers benefits like reduced risk of adjacent segment disease and preserved range of motion, but PROMs for it and ACDF are not significantly different. Current surveys may not detect subtle CDR advantages. In this study, we developed and validated the Forgotten Spine Surgery Score – Cervical (FS3-C) to evaluate postoperative awareness after cervical spine surgery.
Methods: Patients who underwent primary one- or two-level CDR or ACDF at a single institution (2017-2023) with a minimum three-month follow-up were included. Patients with three-level CDR/ACDF, revision of CDR implant, or hybrid CDR-ACDF constructs were excluded. A pilot CDR cohort was administered a 20-item questionnaire via REDCap or phone. Based on psychometric properties, 12 items were selected for the final FS3-C. The CDR validation cohort was co-administered FS3-C and Neck Disability Index (NDI). An ACDF validation cohort was also co-administered FS3-C and NDI.
Results: The pilot cohort included 41 patients (mean age: 45 ± 8 years). Questions with high missing responses or strong ceiling effects were excluded. Eight items were combined into four, creating the final 12-item FS3-C. The CDR validation cohort included 127 patients (mean age: 44 ± 9 years). The FS3-C showed high internal consistency and strong item-total correlation. It correlated strongly with NDI (r=-0.606, p< 0.001). The ACDF cohort included 112 patients (mean age 61 ± 11 years). FS3-C had a higher Cronbach’s alpha than NDI (0.95 vs 0.88). FS3-C differentiated CDR and ACDF outcomes, unlike NDI. Average NDI scores were 5.2 ± 6.2 for CDR and 6.3 ± 6.2 for ACDF (p=0.074). FS3-C scores were 59.9 ± 19.6 for CDR and 53.2 ± 22.2 for ACDF (p=0.012). Effect sizes were 0.17 for NDI and 0.33 for FS3-C.
Conclusion : FS3-C demonstrated strong validity, consistency, and the ability to differentiate outcomes between CDR and ACDF patients. It can detect subtle symptom differences.
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