Predictors of a Favorable Response to Erector Spinae Plane Block for Lumbosacral Radiculopathy

Abstract

Background: The erector spinae plane block (ESPB), which was introduced to manage the thoracic pain, is a technical easy and less invasive ultrasound-guided technique. Although the ESPB is used widely in various clinical situations, no studies have evaluated the association between the clinical outcomes of the ESPB and the numerical changes of the perfusion index (PI).

Objectives: The purpose of this study is to investigate the association between the clinical response following ESPB and other possible factors including the changes of PI.

Study design: Prospective, nonrandomized, and an open-label study.

Setting: The pain clinic of a tertiary university hospital.

Methods: This study included 91 patients of low back pain with degenerative spinal disease who received L4 ESPB using 20 mL of 0.2% ropivacaine. For the predication of clinical outcome, the PI was measured for 30 min at the blocked side subsequent to the ESPB. Various demographic data were also analyzed to predict the clinical outcomes.

Results: The PI of the responder group was higher value than that of the nonresponder group until 30 min but did not show any statistically significant differences. Multivariate logistic regression analysis revealed that the duration of pain (odds ratio [OR], 0.95; 95% CI, 0.90-1.00; P = 0.043), the right side injection (OR, 3.87; 95% CI, 1.42-10.55; P = 0.008), and the PI ratio of 1.5-3 at 10 min (OR, 3.79; 95% CI, 1.36-10.57; P = 0.011), were independent factors associated with successful outcomes.

Limitation: The responder and the nonresponders were categorized using only changes of the numeric rating scale. The categorization based on the changes of functional disability or quality of life was not used.

Conclusion: The right side injection, duration of pain less than 3 months, PI ratio of 1.5-3 at 10 min following the ESPB were associated with successful clinical outcomes.