Oral Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025
The “forgotten spine” as the ultimate goal in fusion surgery: towards the development of a patient-centered outcome measure (115783)
INTRODUCTION
Lumbar spine fusion (LSF) surgeries have increased due to the rising prevalence of degenerative spine disorders and advancements in surgical techniques. Evaluating these procedures from the patient's perspective emphasizes the need for effective patient-reported outcome measures (PROMs). Existing PROMs often focus specifically on symptoms or distinct aspects of the disease, with very few considering the unique patient’s perception of clinical success. Inspired by the Forgotten Joint Score used in joint replacement surgery1, we introduced the Forgotten Spine Score (FSS), a new patient-centered PROM designed to assess to what extent patients "forget" about their fused spines in daily life. This pilot study aimed to develop this novel questionnaire and preliminarily assess its validity and internal consistency.
METHODS
An 18-item questionnaire was developed by a team of experts, including clinicians, study nurses, a biostatistician, and LSF patients. All questionnaire items focused on the subjective awareness of the fused spine segment during daily activities and social interactions. The questionnaire was divided into 4 different subscales related to general awareness, bending and twisting, weight-carrying, and social activities. Patients who underwent single- or multi-level LSF between L1 and S1 due to degenerative disorders at a single institution between 2020 and 2024 were included. Data collection encompassed basic sociodemographic and clinical characteristics such as age, sex, education, date of LSF, type of LSF, number of fused levels, and time since surgery. Patients completed the FSS and the Oswestry Disability Index (ODI). For item selection, Cronbach α, the percentage of missing items, and the frequency of response categories were calculated. The ceiling and floor effects of the scales were described as percentages of patients reporting the best or worst possible score on a scale, respectively. Content and convergent validity were assessed through Spearman correlation between FSS and ODI scores.
RESULTS
Fifty patients (17 males and 33 females) with a mean age of 65.7±9.1 years and an average time since surgery of 23.7±13.2 months were included. Following the collection of FSS scores, three items reached a critical threshold (>30%) of missing responses, which were excluded before the analysis of internal consistency. The remaining 15 items showed a Cronbach α value of 0.94. FSS and ODI scores were significantly correlated (Spearman r: 0.64, p<0.0001; Fig. 1). Furthermore, the FSS showed a higher floor effect (10.0%) compared to the ODI (5.0%).
DISCUSSION
This pilot study demonstrated that the FSS showed high internal consistency, notable face, content, and convergent validity, and a high capacity to capture both best and worst outcomes from a multidimensional, patient-centered perspective. By shifting focus from symptom intensity and disease severity to patients' perception of regaining their lives, the FSS aims to potentially change the PROM scenario in the spine field. The validity of this new score will be confirmed in a comprehensive validation phase on a larger patient population.
Fig. 1. Spearman correlation between FSS and ODI scores.
- Behrend H, Giesinger K, Giesinger JM, Kuster MS. The "forgotten joint" as the ultimate goal in joint arthroplasty: validation of a new patient-reported outcome measure. J Arthroplasty. 2012 Mar;27(3):430-436.e1.