Development of a Novel Retrospective Instrument to Gauge the General Well-Being Index and Lumbar-Specific Disability Index Post-intervention in Lumbar Degenerative Disease

STUDY DESIGN: Validation of a novel retrospective comparative questionnaire to obtain post-intervention outcome data in patients with lumbar degenerative spinal disease.

PURPOSE: Acquiring prospective outcome data for spinal intervention is not frequently feasible in resource-depleted units in certain developing countries. Therefore, a novel retrospective instrument is being validated for clinical use, which can act as a standard method to describe outcomes when data are retrospectively collected.

OVERVIEW OF LITERATURE: The standard method of collecting outcome data after a spinal intervention has been prospective, including the Oswestry Disability Index, Roland-Morris Questionnaire, and Short Form-36. The process of content validation and reliability of the novel retrospective spinal questionnaires is highlighted.

METHODS: Questionnaire items were created based on a literature review, followed by a process of content validation by experts and modification based on expert opinions to achieve an acceptable content validity index (CVI, 0.70-1.00). To calculate factor loadings for each question, a pilot test was subsequently conducted from a pool of patients who underwent lumbar spine surgeries for degenerative spine diseases.

RESULTS: All items achieved a CVI of >0.85 for both relevancy and clarity and were successfully validated after appropriate corrections were made before the second validation phase. Except for Q9 and Q10, which showed low-loading factors in the pooled sample, the remainder of the items had acceptable loading factors across different subgroups, indicating that the passage of time did not affect the results of the exploratory factor analysis.

CONCLUSIONS: The retrospective questionnaire that encompasses the general well-being and lumbar-specific symptoms is a valid and reliable instrument to provide an impression of the outcome after intervention in a patient with a degenerative lumbar spinal disease. A summative score will indicate the overall outcome.