Lumbar nerve root injections: a prospective cohort outcomes study comparing age- and gender-matched patients who returned an outcomes-based postal questionnaire with patients who did not return the postal questionnaire.

Abstract

The purpose of this study is to investigate if relying on postal questionnaires returned by patients provides an accurate representation of reported outcomes from patients receiving imaging-guided lumbar nerve root injections (NRIs). Patients who received imaging-guided transforaminal lumbar NRIs were given short questionnaires inquiring about pain level [numerical rating scale (NRS)] and overall improvement [Patient's Global Impression of Change (PGIC)]. Those who did not return the questionnaires (non-responders) were telephoned and asked about pain level and overall change in condition. Age and gender matching of responders and non-responders resulted in 97 patients in each group. The proportion of patients reporting clinically relevant "improvement" or "worsening" in each group was calculated and the Chi-square test was used to detect differences. NRS and PGIC scores for responders and non-responders were compared using Student's t test and the Mann-Whitney U test, respectively. A higher proportion of non-responders reported clinically relevant improvement (53.6 %) compared to responders (42.6 %) and responders reported significantly higher levels of worsening of condition (p = 0.01). Both responders and non-responders had significant (p ≤ 0.05) improvement on the 20-30-min and 1-month NRS scores compared to their pre-injection baseline scores. Non-responders had significantly higher baseline NRS scores but no significant difference at the 20-30-min and 1-month NRS scores compared to responders. Patients returning postal questionnaires reported less favorable outcomes compared to those who did not return their questionnaires.