Single Epidural Analgesia With Opioid-free IV-PCA Reduces Opioid Consumption in Lumbar Spine Surgery: A Randomized,...

Postoperative pain management after lumbar spine surgery often involves modest to high doses of opioids, which can contribute to the risk of dependence. Epidural analgesia has emerged as a promising opioid-sparing alternative, but its efficacy compared with conventional opioid-based intravenous patient-controlled analgesia (IV-PCA) in a randomized trial has not been established in these patients.

We asked whether an opioid-sparing protocol, compared with conventional opioid-based IV-PCA, (1) provides superior pain control, (2) reduces opioid consumption, and (3) lowers the frequency of opioid-related adverse events.

In this multicenter, randomized, double-blind, parallel-group trial, we enrolled 98 patients undergoing single-level lumbar fusion or decompression. Eligible participants were adults age 20 to 80 years diagnosed with lumbar spinal stenosis or spondylolisthesis. Exclusion criteria included history of prior lumbar surgery, coagulation disorders, or opioid dependence. Patients were randomized to either the epidural opioid-free IV-PCA group (intraoperative single-shot epidural ropivacaine injection with opioid-free IV-PCA; epidural group) or the conventional opioid-based IV-PCA group (fentanyl-based IV-PCA; control group). In the epidural opioid-free group, fentanyl was administered solely as a rescue analgesic for breakthrough pain. All patients and outcome assessors were blinded to group allocation. In the fusion arm, 25 patients were randomized to the epidural group and 25 to the control group; data from all randomized patients (n = 25 in each group) were fully analyzed. In the decompression arm, 24 were randomized to the epidural group and 24 to the control group; data from all randomized patients (n = 24 in each group) were fully analyzed. Three patients (one in the fusion arm and two in the decompression arm) discontinued the intervention because of severe postoperative nausea and vomiting but were included in the final analysis based on the intention-to-treat principle, preventing differential loss to follow-up bias. There were no important differences between treatment and control groups in terms of baseline demographic or clinical data in either study arm. The minimum clinically important difference (MCID) for the numeric rating scale (NRS) pain score was defined as 2 points. The sample size was calculated to detect a 15% reduction in NRS scores (0.9 points), ensuring sensitivity to differences smaller than the MCID of 2 points. Secondary outcomes included total fentanyl consumption, rescue analgesic demand, and opioid-related adverse events.

There were no clinically important differences between the epidural and control groups in either the decompression or the fusion arms of the study in terms of NRS pain scores at any time point (the largest difference was seen at 24 hours in the fusion group, but it was not clinically important: mean ± SD 2.7 ± 1.5 versus 4.4 ± 1.5 points of 10 total, mean difference -1.8 points [95% confidence interval (CI) -2.6 to -0.9]; p = 0.04). However, despite no important differences in pain control, fentanyl consumption was lower in the epidural groups than the control groups of both the fusion arm (122 ± 140 versus 1467 ± 481 µg, mean difference -1345 µg [95% CI -1550 to -1140]; p < 0.001) and the decompression arm (41 ± 51 versus 1046 ± 451 µg, mean difference -1005 µg [95% CI -1196 to -813]; p < 0.001). In the fusion arm of the study, postoperative urinary retention was less common in the epidural group (4% [1 of 25] versus 32% [8 of 25], relative risk 0.13 [95% CI 0.02 to 0.93]; p = 0.02); there were no differences in complications between the epidural and control groups in the decompression arm of the study.

A single epidural ropivacaine injection with opioid-free IV-PCA provided effective pain control, reduced opioid consumption, and decreased urinary retention risk after single-level lumbar spine surgery. This protocol is a viable and effective opioid-sparing strategy.

Level I, therapeutic study.