1. 2024;27;235-242Predictors of a Successful Outcome Following a Thoracic Erector Spinae Plane Block for Cervical Radiculopathy
   Prospective Study
   Ji H. Hong, MD, PhD, Ki Beom Park, MD, PhD, Jae Y. Lee, MD, and Ji H. Park, MD, PhD.

BACKGROUND: The erector spinae plane block (ESPB) is an interfascial plane block for managing neuropathic thoracic pain. Although the ESPB is applied widely in various clinical situations, no studies have evaluated the association between the analgesic outcomes of the ESPB and the numerical changes in the perfusion index (PI) and PI ratio.

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

STUDY DESIGN: A prospective, nonrandomized, and open-label study.

SETTING: The pain clinic of a tertiary university hospital.

METHODS: This study included 92 patients with neck or arm pain who received T2 ESPB using 20 mL of 0.2% ropivacaine. To aid in the prediction of clinical outcomes, the PI was measured at the blocked side for 30 minutes as soon as the ESPB was finished. Various demographic data were also analyzed to predict the clinical outcomes.

RESULTS: Among 92 patients, 59 patients (64%) showed successful treatment outcomes (> 50% reduction in the numerical rating scale score or > 30% reduction in the neck disability index). The baseline PI of the responders was statistically higher than the nonresponders’ (P < 0.05). Also, the responders’ PI demonstrated statistically higher values than the nonresponders’ at the time points of 4, 6, and 8 minutes after the ESPB. Multivariate logistic regression analysis revealed that a higher baseline PI (OR, 1.91; 95% CI, 1.27-2.86; P = 0.002) was an independent factor associated with a successful outcome.

LIMITATIONS: Only a small number of patients with nonspinal diseases were included, except for those who had cervical radiculopathy. Therefore, it is hard to conclude that thoracic ESPB has any therapeutic benefits to patients with nonspinal diseases such as complex regional pain syndrome, adhesive capsulitis, or post-thoracotomy pain syndrome.

CONCLUSION: A successful outcome at 4 weeks after T2 ESPB was achieved in 64% of patients with cervical radiculopathy. A higher baseline PI value was an independent factor associated with a successful response to T2 ESPB.

KEY WORDS: Erector spinae plane block, perfusion index, numerical rating scale, Neck Disability Index