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

Shorter and sweeter: the 16-item version of the SRS questionnaire shows better structural validity than the 20-item version in young patients with spinal deformity

PURPOSE

In patients with adult spinal deformity, it was previously shown that 16 of the non-management items of the SRS-instrument showed a better fit to the theoretical four-factor model (pain, function, self-image, mental health) than did all 20 items. Whether the same phenomenon is observed in data from younger (< 20y) patients, for whom the questionnaire was originally designed, is not currently known.

METHODS

Confirmatory factor analysis was used to evaluate the factor structure of the 20 non-management items of the SRS-instrument completed by 3618 young patients with spinal deformity (75.5% female; mean age, 15.0 ± 2.0 years) and of its equivalence across language versions (2713 English-speaking, 270 Spanish, 264 German, 223 Italian, and 148 French). The root mean square error of approximation (RMSEA) and comparative fit index (CFI) indicated model fit.

RESULTS

Compared with the 20-item version, the 16-item solution significantly increased the fit (p < 0.001) across all language versions, to achieve good model fit (CFI = 0.96, RMSEA = 0.06). For both 16-item and 20-item models, equivalence across languages was not reached, with some items showing weaker item-loading for some languages, in particular German and French.

CONCLUSION

In patients with adolescent idiopathic scoliosis, the shorter 16-item version showed a better fit to the intended 4-factor structure of the SRS-instrument. The wording of some of the items, and/or their equivalence across language versions, may need to be addressed. Questionnaire completion can be a burden for patients; if a shorter, more structurally valid version is available, its use should be encouraged.

Nonoperative management of adolescent idiopathic scoliosis (AIS) using braces

This review presents the state of the art according to the current evidence on nonoperative treatment for adolescent idiopathic scoliosis, focusing on bracing. The definition of braces for the treatment of adolescent idiopathic scoliosis and a short history are provided. The analysis includes biomechanics, types, existing classifications, indications for treatment, time of brace wear and weaning, adherence, three-dimensional modeling, use of ultrasound imaging for bracing, management of treatment, issue of immediate in-brace correction, and documentation of the outcomes usually assessed for brace treatment, including the quality-of-life issues. According to the current evidence, there are two randomized control trials in favor of bracing. There are insufficient data on the superiority of one brace over another, although it is possible to classify and grade braces for efficacy from nonrigid to rigid and very rigid. Nevertheless, there is consensus on patients' management on the need for teamwork focusing on adherence to treatment, acceptability, and family and patient involvement.

SRS-22r question 11 is a valid opioid screen and stratifies opioid consumption

PURPOSE

To validate the Scoliosis Research Society-22r (SRS-22r) question 11 (Q11) response as a measure to assess and quantify opioid consumption.

METHODS

A post hoc analysis of a prospective study regarding opioid use during ASD surgery was performed. Data were collected at enrollment and 2-year follow-up including the SRS-22r and a standardized data collection form (CRF) for self-reported opioid consumption. Responses to Q11 of the SS-22r were compared with responses to the opioid consumption CRF (as measured by morphine equivalent dose (MED)). Inter-rater agreement was calculated. Sensitivity and specificity for the Q11 (+) responses were calculated using MED reports as the "true" value.

RESULTS

Cohen's kappa indicated almost perfect agreement between the MED CRF and Q11 (k = 0.878, p < 0.001). Mean daily MED consumption for patients reporting "Daily Narcotic" use was 62.0 (Median: 38.7, SD 87.5) mg; for patients reporting "Narcotics weekly or less", mean daily MED consumption was 21.6 (15.0, 29.0) mg. The positive Q11 responses were 96% sensitive and 92% specific for opioid users.

CONCLUSION

SRS-22r Q11 exhibits almost perfect agreement with an independent questionnaire designed to assess opioid consumption in this cohort. "Daily narcotic" users report nearly three times the mean daily MED of "Weekly or less" users (62.0 ± 87.5 mg vs 21.6 ± 29 mg, p = 0.037). Q11 exhibited excellent sensitivity and specificity for determining opioid users and non-users. Given the need for opioid research in ASD, Q11 may be useful to use existing registries and observational cohorts to design more definitive studies regarding opioid consumption.

LEVEL OF EVIDENCE

III.

Long-Term Health-Related Quality of Life After Harrington Instrumentation and Fusion for Adolescent Idiopathic Scoliosis: A Minimum 40-Year Follow-up

BACKGROUND

Despite its importance for clinical decisions, the long-term consequences of posterior spinal instrumentation and fusion (PSIF) for adolescent idiopathic scoliosis (AIS), particularly in the lower lumbar spine, remain unclear. This study evaluates the long-term health-related quality of life and the need for a further surgical procedure in patients treated with Harrington instrumentation from 1961 to 1977 according to the lowest instrumented vertebra (LIV) and in comparison with age-matched norms.

METHODS

A search was performed to identify and contact the 314 identified patients with AIS treated with PSIF by Dr. L.A. Goldstein. The assessment included identified subsequent spine surgery, the Oswestry Disability Index (ODI), Scoliosis Research Society-7 (SRS-7), EuroQol-5 Dimensions (EQ-5D), and Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29). The health-related quality of life was compared with U.S. norms and, within the cohort, was compared by patient factors, LIV, and subsequent spine surgery.

RESULTS

In this study, 134 patients (42.7%) were identified; 24 (7.6%) had died, 81 (25.8%) consented to participate in the study, and 29 (9.2%) declined participation. The mean follow-up was 45.4 years (range, 40 to 56 years). There were 81 patients who completed the surveys, 77 patients who completed the SRS-7, 77 patients who completed the ODI, and 76 patients who completed the PROMIS-29 and EQ-5D. There were 12.8% of patients with LIV L3 or proximal and 36.4% with LIV L4 or distal who had an additional surgical procedure (odds ratio, 3.98). Comparing the ODI of patients who had undergone an additional surgical procedure with those who had not showed 42% and 73% minimal disability, 53% and 23% moderate disability, and 5% and 2% severe disability. Of the patients who had not undergone an additional surgical procedure, those with LIV L3 or proximal had mean scores of 14.12 points for the ODI and 23.3 points for the SRS-7 and those with LIV L4 or distal had mean scores of 17.9 points for the ODI and 22.7 points for the SRS-7; these differences were not significant. The mean PROMIS-29 and EQ-5D scores were not different from normal U.S. age-based means.

CONCLUSIONS

Patients with AIS treated with PSIF at a mean 45-year follow-up and LIV L4 or distal had a higher rate of undergoing an additional surgical procedure than those with LIV L3 or proximal. Patients undergoing an additional surgical procedure had lower health-related quality of life than those who did not. Despite this, there was no difference in health-related quality of life for patients with LIV L4 or distal compared with patients with LIV L3 or proximal. This cohort of patients with AIS treated with PSIF demonstrates normal self-reported health-related quality of life compared with the age-matched general population. These long-term outcomes of PSIF for AIS are encouraging.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Psychometric Properties of the Scoliosis Research Society Questionnaire (Version 22r) Domains Among Adults With Spinal Deformity: A Rasch Measurement Theory Analysis

Objective

Adult spinal deformity (ASD) have lower health-related quality of life (HRQoL) compared to the general population. Applying Rasch measurement theory (RMT), this study tested the revised Scoliosis Research Society-22 (SRS-22r) HRQoL instrument among symptomatic adult patients with degenerative spinal disorders and varying degrees of ASD.

Methods

SRS-22r data from 637 outpatient spine clinic patients with degenerative spine conditions were investigated for unidimensionality, item/scale fit, differential item functioning (DIF), scale coverage/targeting, and person separation index (PSI) using RMT.

Results

Unidimensionality of the SRS-22r was not supported for either the total score or for 3 of its 5 domains. Item fit was acceptable for 11/22 items. The individual domains showed good coverage despite the degree of structural disorders. Ordered thresholds were achieved by merging response categories in some of the items. DIF towards age or sex was found in 11/22 items and in some domain items. The PSI exceeded 0.7 for the SRS-22r total score.

Conclusion

The individual domain scores of the SRS-22r perform better than the total score providing good coverage and targeting among patients with ASD. Refinements of items and domains may improve the structural validity of the instrument to meet the criteria for measuring ASD patients, even when multidimensionality persists.

Mismatch Between Pelvic Incidence and Lumbar Lordosis is the Key Sagittal Plane Determinant of Patient Outcome at Minimum 40 Years After Instrumented Fusion for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective review.

OBJECTIVE

Assess measures of spinal-pelvic balance in predicting functional outcome in patients who underwent posterior spinal fusion for adolescent idiopathic scoliosis (AIS) at minimum 40-year follow-up.

SUMMARY OF BACKGROUND DATA

Back pain and long-term function are considered when choosing levels for surgery in AIS patients. Three hundred and fourteen patients underwent fusion for AIS between 1961 and 1977. One hundred and thirty-four patients were located for potential long-term follow-up.

METHODS

With Institutional Review Board approval, medical records and public resources were used to locate patients. Patients completed health-related quality of life (HRQoL) instruments, and returned for assessment including full radiographs. Radiographs were analyzed for scoliosis measures, and recognized spinal-pelvic measures including the lumbar lordosis, sagittal vertical axis (SVA), pelvic incidence, and pelvic tilt (PT). Bivariate and multivariable analyses were performed to assess the association between spinal-pelvic measures and patient-reported outcomes.

RESULTS

Thirty-five of 134 patients agreed to return for complete HRQoL and radiographic follow-up. There were no differences at baseline between those agreeing and declining participation. The cohort was 94% female, had an average age of 60.5 years, and average follow-up of 46 years. In bivariate analysis, pelvic incidence and lumbar lordosis difference (PI-LL) was the only spinal-pelvic parameter which statistically discriminated between patients doing well and not, as assessed by the Oswestry Disability Index and the Patient-reported Outcomes Measurement Information System (PROMIS) Pain Interference and Fatigue instruments. In multivariable analysis, (PI-LL > 9°) was associated with worse scores in PROMIS-Pain Interference, Physical Function, Depression, Fatigue, Social Function and the total Oswestry score. An SVA > 50 mm was associated with worse scores in the Scoliosis Research Society-7.

CONCLUSION

In a cohort of 35 patients with average follow-up of 46 years after posterior spinal instrumentation with Harrington rods (PSIF) for AIS, spinal-pelvic mismatch as identified by (PI-LL > 9°) was associated with inferior HRQoL outcomes. Other spinal-pelvic measures (SVA and PT) were not reliably associated with inferior HRQoL.Level of Evidence: 4.

State-of-the-art: outcome assessment in adult spinal deformity

Adult spinal deformity (ASD) is a diagnosis that encompasses heterogeneous disorders with an increasing prevalence. This increasing prevalence may be due to greater patient longevity or greater awareness of available treatments. Outcome assessment in ASD has evolved over the last 3 decades from physician-based assessments to a patient-centered perception of improvement. Outcome assessment that is reliable, accurate and responsive to change is especially important in ASD, as surgical treatment is known to carry a high cost and complication rate Glassman (Spine Deform 3:199-203, 2015); Glassman (Spine (Phila Pa 1976) 32: 2764-2770, 2007); Smith (J Neurosurg Spine 25:1-14, 2016). In an era of value-based care, diagnosis associated with such heterogeneity and high cost must provide sound evidence to support the cost versus outcome ratio. Numerous general health and disease specific patient-reported outcome measures (PROMs) have been utilized in ASD. We discuss these instruments in detail in the following state-of-the-art review.

Further validation of the Scoliosis Research Society (SRS-30) questionnaire among adult patients with degenerative spinal disorder

PURPOSE

The Scoliosis Research Society (SRS-30) questionnaire proved valid in measuring health-related quality of life (HRQoL) in adult patients with spinal deformity or degenerative disease. This study further assesses the validity of the SRS-30 by comparing its results with other HRQoL instruments, such as Oswestry disability index (ODI) and the RAND-36, among unselected adult patients with degenerative spinal disorder.

MATERIALS AND METHODS

628 consecutive patients completed the SRS-30, the ODI, the pain visual analog scale (VAS), and RAND-36 questionnaires. Using a 9 mm minimal important difference threshold of the VAS, patients were divided into three groups of symptom location: back pain (n = 226), lower extremity pain (n = 161), and combination of both (n = 241). Statistical and illustrative tests using beta coefficients, Rasch measurement analytics, and score distributions were used for analysis.

RESULTS

The SRS-30 functioned well for all three subgroups. There were small differences in convergent validity of the SRS-30 compared to the ODI and the RAND-36 between the three subgroups. The SRS-30 performed similarly in different pain groups independent of age, gender, or deformity severity. The scale displayed good coverage and targeting for all three subgroups.

CONCLUSIONS

The SRS-30 proved to provide valid HRQoL scores for all adult patients with degenerative spinal disorders. Implications for Rehabilitation Degenerative spinal conditions associated with spinal deformities are common in patients over 60 years. Low back pain is globally the leading cause of disability. The applicability of the Scoliosis Research Society (SRS-30) questionnaire has not been tested in relation to different pain origins. The SRS-30 proved to provide valid health-related quality of life assessment among patients with degenerative spinal disease independent of pain location. The SRS-30 questionnaire can be used to assess the level of disability and rehabilitation of patients with degenerative spinal disease.

Translation and Cross-cultural Adaptation of the Chinese Version of the Self-care of Hypertension Inventory in Older Adults

BACKGROUND

Hypertension is highly prevalent among the older adults. Self-care is an effective method for the secondary prevention of hypertension, but until now, there has been no specialized instrument to evaluate the ability for self-care in elderly Chinese patients with hypertension.

OBJECTIVES

The aims of this study were to cross-culturally translate the Self-care of Hypertension Inventory into Chinese and apply it to elderly patients with preliminary hypertension.

METHODS

This is a methodological study with steps that included translation, synthesis, back-translation, back-translation review, expert committee review, pretesting, and submission to authors. We conducted preliminary psychometric analyses that included content validity, item-total correlation, internal consistency reliability, principal factor analysis, and test/retest reliability.

RESULTS

The translation equivalence was obtained between the adapted version and the original scale. The item-level content validity index had a range of 0.833 to 1. The scale-level content validity average method and Cronbach α were 0.986 and 0.858 for the total scale, respectively. The test/retest reliability was 0.949. Principal factor analyses showed the presence of 4, 1, and 1 latent factors in 3 separate subscales.

CONCLUSIONS

The Self-care of Hypertension Inventory has been successfully translated and cross-culturally adapted to Chinese. It is suitable for application to elderly Chinese patients with hypertension.

Factor analysis of the SRS-22 outcome assessment instrument in patients with adult spinal deformity

PURPOSE

Designed for patients with adolescent idiopathic scoliosis, the SRS-22 is now widely used as an outcome instrument in patients with adult spinal deformity (ASD). No studies have confirmed the four-factor structure (pain, function, self-image, mental health) of the SRS-22 in ASD and under different contexts. Factorial invariance of an instrument over time and in different languages is essential to allow for precise interpretations of treatment success and comparisons across studies. This study sought to evaluate the invariance of the SRS-22 structure across different languages and sub-groups of ASD patients.

METHODS

Confirmatory factor analysis was performed on the 20 non-management items of the SRS-22 with data from 245 American English-, 428 Spanish-, 229 Turkish-, 95 French-, and 195 German-speaking patients. Item loading invariance was compared across languages, age groups, etiologies, treatment groups, and assessment times. A separate sample of SRS-22 data from 772 American surgical patients with ASD was used for cross-validation.

RESULTS

The factor structure fitted significantly better to the proposed four-factor solution than to a unifactorial solution. However, items 14 (personal relationships), 15 (financial difficulties), and 17 (days off work) consistently showed weak item loading within their factors across all language versions and in both baseline and follow-up datasets. A trimmed SRS (16 non-management items) that used the four least problematic items in each of the four domains yielded better-fitting models across all languages, but equivalence was still not reached. With this shorter version there was equivalence of item loading with respect to treatment (surgery vs conservative), time of assessment (baseline vs 12 months follow-up), and etiology (degenerative vs idiopathic), but not age (< vs ≥50 years). All findings were confirmed in the cross-validation sample.

CONCLUSION

We recommend removal of the worst-fitting items from each of the four domains of the SRS-instrument (items 3, 14, 15, 17), together with adaptation and standardization of other items across language versions, to provide an improved version of the instrument with just 16 non-management items.