Are Modic changes related to outcomes in lumbar disc herniation patients treated with imaging-guided lumbar nerve root blocks?

Objective: To compare outcomes after imaging-guided transforaminal lumbar nerve root blocks in MRI confirmed symptomatic disc herniation patients with and without Modic changes (MC). Methods: Consecutive adult patients with MRI confirmed symptomatic lumbar disc herniations and an imaging-guided lumbar nerve root block injection who returned an outcomes questionnaire are included. Numerical rating scale (NRS) pain data was collected prior to injection and 20–30 min after injection. NRS and overall improvement were assessed using the patient's global impression of change (PGIC) scale at 1 day, 1 week and 1 month post injection. The proportion of patients with and without MC on MRI as well as Modic I and Modic II was calculated. These groups were compared for clinically relevant 'improvement' using the Chi-squared test. Baseline and follow-up NRS scores were compared for the groups using the unpaired t-test. Results: 346 patients are included with MC present in 57%. A higher percentage of patients without MC reported 'improvement' and a higher percentage of patients with MC reported 'worsening' but this did not reach statistical significance. The numerical scores on the PGIC and NRS scales showed that patients with MC had significantly higher pain and worse overall improvement scores at 1 month (p = 0.048 and p = 0.03) and a significantly lower 1 month NRS change score (p = 0.04). Conclusions: Patients with MRI confirmed symptomatic lumbar disc herniations and MC report significantly lower levels of pain reduction after a lumbar nerve root block compared to patients without MC