Neurosurgery Resident University of Toronto Toronto, Ontario, Canada
Disclosure(s):
Armaan K. Malhotra, MD: No financial relationships to disclose
Introduction: Existing degenerative cervical myelopathy (DCM) severity scales are limited by arbitrary response item hierarchy, poor reliability, and inadequate sensitivity to change, creating a strong impetus for development of a practical measurement tool with improved psychometric properties. To this end, we have created a new DCM specific patient-reported outcome measure: the Cervical Myelopathy Severity Index (CMSI).
Methods: Phase 1: Item generation was performed using semi-structured patient focus groups gauging the relative importance of symptoms and functional limitations; a resultant preliminary questionnaire was generated. Phase 2: Item reduction was performed in a prospective fashion with patients enrolled into three categories: 1) observation group (DCM patients not requiring surgery), 2) pre-operative group and 3) post-operative group. The questionnaire was completed at baseline and 2 weeks later. Response items were collated within subgroups and the total cohort for item severity and item importance. Spine surgeons were surveyed for specialist perception of item importance. Final item reduction was based on clinician item importance scores, patient importance and severity scores, inter-item reliability and inter-item spearman correlation based on criteria defined a priori.
Results: Phase 1: There were 42 items were generated based on focus group interviews involving 22 patients. Phase 2: 98 patients and 51 surgeons participated in item reduction by ranking relative importance and severity. Patients completed the CMSI at 2 independent time points totaling 189 patient responses and 51 surgeon responses. There were 23 items remaining after application of median importance and severity thresholds and weighted kappa cutoffs (>0.60). After elimination of highly correlated (>0.80) items the final CMSI questionnaire list included 14 items.
Conclusion : We performed a patient-centered, specialist-informed item generation, reduction, and measurement property evaluation for the CMSI, a new DCM clinical measurement tool. Future efforts will aim to validate this tool and compare its properties to existing gold standard myelopathy measurement indices.
