1. 2022;25;E733-E738Effect of Opioid Use on Results of Interventional Back Pain Management on Patients With Suspected Facet-mediated Chronic Back Pain
   Retrospective Study
   Aet Ristmagi, MD, and Hannu Heikkila, MD, PhD.

BACKGROUND: Preoperative exposure to opioids has recently shown to be associated with poor outcomes after elective major surgery, but little is known as to how pretreatment opioid use affects results of interventional back pain management.

OBJECTIVE: We aimed to determine the effect of pretreatment opioid use on outcomes after interventional pain management procedures on patients with chronic back pain.

STUDY DESIGN: A retrospective study.

SETTING: Department of Physical Medicine and Rehabilitation at Satakunta Central Hospital (Satasairaala), Finland.

METHODS: A high-volume, single-center, quality register analysis was performed on patients who underwent interventional pain management for suspected facet-mediated chronic back pain as a part of a multidisciplinary pain management program. Chronic opioid use was defined as having a concurrent opioid prescription for 90 days.

RESULTS: A total of 797 patients underwent an intervention during the study period from August 1, 2019 through December 31, 2020. Pretreatment opioid use was present in 262 patients (33%). Patients with chronic back pain using opioids reported significantly more pain and discomfort before treatment as well as lowered working ability. Facet joint medial branch blocks resulted in significant improvement for both groups directly after the treatment as well as at 2-hours follow-up. However, the nonopioid group reported significantly more improvement at 2-days follow-up as well as at one month follow-up compared to opioid users. Opioid users reported nearly the same pain level at one-month follow-up as they did before treatment.

LIMITATIONS: As a single-center analysis, these data may not be generalizable to other institutions. A retrospective study may include inevitable bias. The disease processes themselves may possibly predispose patients to different degrees of opoid use. Although we have identified preoperative opioid use as a risk factor for treatment failure, we were unable to determine the size of the association based on our statistical analysis and sample size. Pain intensity evaluation using the visual analog scale is inevitably subjective.

CONCLUSION: Pretreatment opioid use is associated with greater pain discomfort, impairment, and reduced functional ability, as well as poorer long-term effect of interventional back pain treatment at one-month follow-up. In our study, opioid users reported the same positive effects of facet joint nerve blocks immediately after the treatment and 2 hours after the treatment, but a significantly smaller effect at one-month follow-up. This could indicate that opioid use may diminish the effects of pain treatments by affecting relearning, behavioral changes, and central pain modulation. These findings may help providers understand the effect of pretreatment opioid use on patient care, and its implications on hospital and societal costs.

KEY WORDS: Opioids, interventional pain management, medial branch block, outcome