- •Substantial Clinical Benefit links meaningful change to surgical intervention.
- •Neck Disability Index is a viable metric for evaluating cervical myelopathy.
- •Patient derived outcome measures are time sensitive.
- •Patient derived outcome measures should be calibrated for follow-up time.
Patient-reported outcome measures are increasingly used to access pain, disability, physical function, and mental status to quantify effectiveness of surgical intervention in cervical myelopathy, yet each score has little meaning without established thresholds linked to clinical benefit. We set out to develop thresholds for substantial clinical benefit (SCB) in patients undergoing surgery for cervical myelopathy and to evaluate the effect of length of follow-up on SCB thresholds.
Thirty-five patients undergoing spinal surgery for progressive cervical myelopathy were tracked from 2005 to 2015. Observations were categorized into three groups: short-term, intermediate, and long-term, corresponding to average follow-up intervals of 3.8, 9.2, and 29.0 months. SCB thresholds were calculated for neck visual analog score (VAS), Neck Disability Index (NDI), Short Form-12 physical (PCS), SF-12 mental component scores (MCS), and modified Japanese Orthopedic Association score (mJOA) using receiver operating curve analysis with a 5-level patient satisfaction index as the anchor.
SCB thresholds for each outcome measure were obtained with a range of areas under the curve indicating varying degrees of discriminatory ability, reported with increasing length of follow-up. NDI and PCS were most discriminatory of SCB at any time period. Stratification of thresholds by length of time revealed a significant effect of follow-up time with NDI but not PCS.
NDI and PCS thresholds have significantly strong discriminatory value in identifying patients receiving substantial clinical benefit with regard to cervical myelopathy. When NDI is used to predict outcome, choosing thresholds calibrated for follow-up time is recommended to maximize predictive power.
Abbreviations:AUC (area under the curve), CDM (cervical degenerative myelopathy), CI (confidence interval), IT (intermediate follow-up), LT (long-term follow-up), MCID (minimal clinically important difference), MCS (mental component score), mJOA (modified Japanese Orthopedic Association score), NDI (Neck Disability Index), PCS (physical component score), PROM (patient-reported outcome measures), PSI (patient satisfaction index), ROC (receiver operating curve), SCB (substantial clinical benefit), ST (short-term follow-up), VAS (visual analog scale)
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- Degenerative cervical myelopathy: epidemiology, genetics, and pathogenesis.Spine (Phila Pa 1976). 2015; 40: E675-693
- Neurological manifestations of cervical spondylosis: an overview of signs, symptoms, and pathophysiology.Neurosurgery. 2007; 60: S14-20
- Usefulness of minimum clinically important difference for assessing patients with subaxial degenerative cervical spine disease: statistical versus substantial clinical benefit.Acta Neurochir (Wien). 2013; 155 (discussion 2355): 2345-2354
- Measuring surgical outcomes in cervical spondylotic myelopathy patients undergoing anterior cervical discectomy and fusion: assessment of minimum clinically important difference.PLoS One. 2013; 8e67408
- Cervical laminectomy and dentate ligament section for cervical spondylotic myelopathy.J Spinal Disord. 1991; 4: 286-295
- Neurological recovery after surgical decompression in patients with cervical spondylotic myelopathy - a prospective study.Int Orthop. 2008; 32: 273-278
- Cervical surgical techniques for the treatment of cervical spondylotic myelopathy.J Neurosurg Spine. 2009; 11: 130-141
- Functional outcome instruments used for cervical spondylotic myelopathy: interscale correlation and prediction of preference-based quality of life.Spine J. 2013; 13: 902-907
- Assessment of the minimum clinically important difference in neurological function and quality of life after surgery in cervical spondylotic myelopathy patients: a prospective cohort study.Eur Spine J. 2015; 24: 2918-2923
- Defining clinically meaningful change in health-related quality of life.J Clin Epidemiol. 2003; 56: 395-407
- Evidence-based medicine in health care reform.Otolaryngol Head Neck Surg. 2011; 145: 526-529
- Guyatt GH. Measurement of health status. Ascertaining the minimal clinically important difference.Control Clin Trials. 1989; 10: 407-415
- Multimodal assessment after surgery for cervical spondylotic myelopathy.J Neurosurg Spine. 2005; 2: 526-534
- Defining substantial clinical benefit following lumbar spine arthrodesis.J Bone Joint Surg Am. 2008; 90: 1839-1847
- Correlation of quality of life and functional outcome measures for cervical spondylotic myelopathy.J Neurosurg Spine. 2016; 24: 483-489
- The Neck Disability Index: a study of reliability and validity.J Manipulative Physiol Ther. 1991; 14: 409-415
- A 12-Item Short-Form Health Survey: construction of scales and preliminary tests of reliability and validity.Med Care. 1996; 34: 220-233
- Applied Logistic Regressin.2nd ed. John Wiley & Sons, Hoboken, NJ2000
- Using ROC curves to choose minimally important change thresholds when sensitivity and specificity are valued equally: the forgotten lesson of pythagoras. theoretical considerations and an example application of change in health status.PLoS One. 2014; 9e114468
- Functional outcomes assessment for cervical degenerative disease.J Neurosurg Spine. 2009; 11: 238-244
- Interobserver and intraobserver reliability of the Japanese orthopaedic association scoring system for evaluation of cervical compression myelopathy.Spine (Phila Pa 1976). 2001; 26 (discussion 1895): 1890-1894
- Japanese orthopaedic association back pain evaluation questionnaire (JOABPEQ) as an outcome measure for patients with low back pain: reference values in healthy volunteers.J Orthop Sci. 2015; 20: 264-280
- Assessment of postoperative pain management: patient satisfaction and perceived helpfulness.Clin J Pain. 1997; 13: 229-236
- Understanding inconsistencies in patient-reported outcomes after spine treatment: response shift phenomena.Spine J. 2009; 9: 1039-1045
Published online: January 16, 2019
Accepted: December 12, 2018
Received: March 29, 2018
© 2018 Published by Elsevier Ltd.