Validity, Reliability, and Responsiveness of SRS-7 as an Outcomes Assessment Instrument for Operatively Treated Patients With Adult Spinal Deformity.

Abstract

Study design

A retrospective analysis.

Objective

The aim of our study was to compare the normality, concurrent validity, internal consistency, responsiveness, and dimensionality of an item response theory-derived seven-question instrument (SRS-7), against the Scoliosis Research Society-22r (SRS-22r) questionnaire in operatively treated patients with adult spinal deformity (ASD).

Summary of background data

Compared with SRS-22r, SRS-7 (which has been validated in operatively treated patients with adolescent idiopathic scoliosis) has advantages of being short, unidimensional, and linear.

Methods

A prospective database of ASD patients was queried for patients 18 years or older who were operatively treated, and who answered pre- and postoperative (at 2-year follow-up) SRS-22r questions (n = 276). Corresponding SRS-7 scores were calculated using answers to SRS-22r items 1, 4, 6, 10, 18, 19, and 20. Significance was set at a P value less than 0.01.

Results

SRS-7 and SRS-22r were normally distributed preoperatively but not postoperatively. SRS-7 and SRS-22r scores had high correlation both preoperatively (r = 0.76, P < 0.01) and postoperatively (r = 0.83, P < 0.01). The internal consistency reliability Cronbach α values were 0.61 (SRS-7) and 0.83 (SRS-22r) preoperatively and 0.91 (SRS-7) and 0.95 (SRS-22r) postoperatively. SRS-7 was found to be more responsive than SRS-22r with measures of effect size: Cohen d = 1.21 versus 1.13, Hedge g = 1.21 versus 1.13, and effect size correlation r = 0.52 versus 0.49. Iterative principal factor analysis of pre- and postoperative scores showed the presence of one dominant latent factor in SRS-7 (unidimensionality) and four latent factors in SRS-22r (multidimensionality).

Conclusion

SRS-7 is a valid, reliable, responsive, and unidimensional instrument, which can be used as a short-form alternative to the SRS-22r for assessing global changes in patient-reported outcomes over time in patients with ASD.

Level of evidence

3.

Department

Description

Provenance

Citation

Published Version (Please cite this version)

10.1097/brs.0000000000001540

Publication Info

Jain, Amit, Virginie Lafage, Michael P Kelly, Hamid Hassanzadeh, Brian J Neuman, Daniel M Sciubba, Shay Bess, Christopher I Shaffrey, et al. (2016). Validity, Reliability, and Responsiveness of SRS-7 as an Outcomes Assessment Instrument for Operatively Treated Patients With Adult Spinal Deformity. Spine, 41(18). pp. 1463–1468. 10.1097/brs.0000000000001540 Retrieved from https://hdl.handle.net/10161/28409.

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Scholars@Duke

Shaffrey

Christopher Ignatius Shaffrey

Professor of Orthopaedic Surgery

I have more than 25 years of experience treating patients of all ages with spinal disorders. I have had an interest in the management of spinal disorders since starting my medical education. I performed residencies in both orthopaedic surgery and neurosurgery to gain a comprehensive understanding of the entire range of spinal disorders. My goal has been to find innovative ways to manage the range of spinal conditions, straightforward to complex. I have a focus on managing patients with complex spinal disorders. My patient evaluation and management philosophy is to provide engaged, compassionate care that focuses on providing the simplest and least aggressive treatment option for a particular condition. In many cases, non-operative treatment options exist to improve a patient’s symptoms. I have been actively engaged in clinical research to find the best ways to manage spinal disorders in order to achieve better results with fewer complications.


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