Predictors of a Successful Outcome Following a Thoracic Erector Spinae Plane Block for Cervical Radiculopathy.

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.

Sympatholytic Effect of the High Thoracic Erector Spinae Plane Block.

BACKGROUND: The erector spinae plane block (ESPB), which was introduced for the management of thoracic pain, is a technically easy and relatively noninvasive ultrasound (ULSD)-guided technique. Although the ESPB is used widely in variable clinical situations, its sympatholytic effect has never been studied. OBJECTIVES: The purpose of this study is to demonstrate the sympatholytic effect of the high thoracic ESPB by comparing the blocked and unblocked sides of patients' upper extremities, using the changes in the perfusion index (PI). STUDY DESIGN: Prospective, single-group, and open-label study. SETTING: The study was carried out in the pain clinic of a tertiary university hospital. METHODS: This study included 47 patients with upper extremity pain and various diseases who received T2 or T3 ESPBs using 20 mL of 0.2% ropivacaine. For the evaluation of the sympatholytic effect, measurements were taken on the numeric rating scale (NRS), the neck disability index (NDI), and the PI. RESULTS: The PIs of the blocked sides demonstrated significant increases at 10, 20, and 30 minutes compared to the PIs of the baseline and unblocked sides (P < 0.001). The PI ratio at 10 minutes was 2.74 ± 1.65, which was the highest value during the measurement period. Until 30 minutes after the ESPB, the PI ratio was significantly higher in the blocked side than in the unblocked side. During the study period, significant reductions in NRS and NDI scores were found irrespective of disease entity. LIMITATION: The period of PI measurement was only 30 minutes, so we could not determine the time point when the PI returned to the baseline value. CONCLUSION: The high thoracic ESPB was effective in relieving upper extremity pain in diverse disease entities, and the PIs of patients' blocked sides demonstrated significant increases over the baseline value and contralateral unblocked sides.

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

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.