Imaging-guided lumbar facet injections: Is there a difference in outcomes between low back pain patients who remember to return a postal questionnaire and those who do not?

Abstract

Objectives: To determine whether data obtained from patients returning postal questionnaires accurately reflect how patients receiving imaging-guided lumbar facet injections respond. Methods: Seventy-eight patients receiving lumbar facet joint injections who returned an outcomes questionnaire (responders) were age and gender matched with 78 patients who did not return the postal questionnaire (non-responders) after facet joint injections. Baseline numerical rating scale (NRS) pain data were collected. NRS and Patients' Global Impression of Change (PGIC) data were collected 1 month after injection by postal questionnaire or telephone interview. Differences in NRS scores were calculated using the unpaired t-test. One level injection patients were compared to patients having ≥2 levels injected using the paired and unpaired t-test. The proportion of patients reporting significant improvement in each group was calculated. Results: NRS scores were significantly improved compared to baseline (p = 0.0001). Thirty-eight percent of responders were significantly improved compared to 50 % of non-responders. Patients having ≥2 levels injected reported significantly higher baseline NRS scores, but by 1 month there was no difference in NRS scores between groups. Conclusions: Patients returning postal questionnaires report a less favourable outcome. Telephone interview patients having injections at more than one level have better outcomes. Main messages: • Patients returning postal questionnaires report worse outcomes after facet injection.• Method of data collection should be considered when reporting treatment outcomes.• Patients receiving facet injections at more than one level report greater levels of pain reduction. © 2012 The Author(s).