Development of a Modified Version of the Spinal Function Sort (M-SFS): A Mixed Method Approach

Abstract

Purpose To develop a modified version of the spinal function sort (M-SFS) by measuring work-related self-efficacy beliefs in patients with chronic low back pain. Methods A mixed method design consisting of three different methods (M1–3) was performed. In semi-structured interviews participants were asked how often they performed the activities of the 50 SFS items in 1 week, and which spinal postures and movements were associated with their back pain (M1). Quantitative analysis of previously obtained SFS data investigated internal consistency, unidimensionality, item response, and floor and ceiling effect (M2). Experts rated the SFS items based on their relevance (M3). The findings from these methods were used within a final scoring system for item reduction. Results From semi-structured interviews with 17 participants, eight new items emerged (M1). Quantitative analysis of 565 data sets (M2) revealed very high internal consistency of all items (Cronbach’s alpha = 0.98) indicating item redundancy; unidimensionality of the SFS was supported by principal component analysis; good item response was confirmed by Rasch analysis; and a floor effect of four items depicting very heavy material handling was found. Experts agreed on 8 out of the 50 SFS as relevant (M3). From the original SFS, 12 items met the predefined summary score of 9. Conclusions A modified version of the SFS with 20 items has been developed. Feasibility, reliability and validity of this modified version must be tested before it can be used in clinical practice.

Measurement Properties of the Modified Spinal Function Sort (M-SFS): Is It Reliable and Valid in Workers with Chronic Musculoskeletal Pain?

“…Principal component analysis confirmed the existence of main components lifting & carrying, activities with bending of the spine, prolonged body postur es. These components are in line with the themes that emerged from the previous mixed-method study based on expert opinions, interviews with patients and item analysis from clinical study-data [ 14 ].…”

“…Higher scores indicated higher PSE. The development of the M-SFS has been described in detail elsewhere [ 14 ].…”

“…Another critique was that the SFS does not include pictures of prolonged work postures, ambulation and the images are outdated [ 12 , 13 ]. Therefore, the 20-item Modified Spinal Function Sort (M-SFS) was developed using a mixed methods approach, which involved expert opinions, interviews with patients and item analysis based on data from clinical studies [ 14 ]. Validity and reliability of the M-SFS has not been established yet.…”

Passive Trunk Exoskeleton Acceptability and Effects on Self-efficacy in Employees with Low-Back Pain: A Mixed Method Approach

“…For the quantitative analysis we assessed work-related self-efficacy by using the Modified Spinal Function Sort (M-SFS), a valid and reliable picture-based questionnaire that can be used in patients with chronic musculoskeletal disorders [ 28 ]. It consists of 20 daily activities, that involve loading of the spine.…”

Selbsteinschätzung der funktionellen Leistungsfähigkeit (SELF): Messeigenschaften in der beruflich orientierten medizinischen Rehabilitation

“…Zum gleichen Zeitpunkt erfolgte zudem die Erhebung der wahrgenommenen Fähigkeit zur Bewältigung psychischer Arbeitsanforderungen, dem WAI entsprechend mit einem von "sehr gut" bis "sehr schlecht" reichenden fünfstufigen Antwortformat. Die Arbeitsunfähigkeitstage innerhalb der vergangenen12 Monate wurden für die weiteren Analysen dichotomisiert ( ≤ 26 vs. > 26 Wochen). Die ICD10 codier-Erhebungszeitpunkte des SELF und weiterer Instrumente.…”