Abstract
PURPOSE: To evaluate the impact of bilateral ultrasound-guided erector spinae plane blocks (ESPBs) on pain and opioid-related outcomes in a surgical population with chronic pain. METHODS: A retrospective, observational cohort study. Clinical data were extracted from the electronic medical records of patients who underwent lumbar fusion (February 2018 - July 2020). Eligible patients had a confirmed history/diagnosis of chronic pain starting >3 months before surgery and received either bilateral ESPBs or no ESPBs. Patients were matched on demographic variables (sex, age, race, BMI, ASA Classification, and preoperative opioid use) in a 1:1 ratio. The primary outcome was median opioid consumption (morphine equivalent dose, MED) 24 hours post-surgery (hydromorphone iv-PCA and oral). Secondary outcomes included Numeric Rating Scale (NRS) pain scores, opioid consumption up to 48 hours post-surgery, and hospital length of stay (LOS). Group differences were analyzed using bivariable and multivariable regression. RESULTS: Of 72 patients, 36 received ultrasound-guided ESPBs and 36 did not. Baseline demographics showed no significant differences. On bivariable analysis, ESPBs were associated with significantly lower 24-hour opioid consumption (79 mg MED vs 116 mg MED, p=0.024) and shorter LOS (82 hours, 95% CI 51-106 vs 126 hours, 95% CI 101-167, p<0.001). No significant differences in NRS pain scores were found up to 48 hours post-surgery. Multivariable analysis confirmed significant reductions in 24-hour opioid consumption (-44, 95% CI -1.06 - -87.55, p=0.044), IV-PCA use (-22, 95% CI -1.59 - -56.77, p=0.038), and LOS (-38, 95% CI -10.074 - -66.22, p=0.008) in the ESPB group without differences in NRS pain scores. CONCLUSION: ESPBs were associated with statistically and clinically significant reductions in 24-hour opioid consumption and LOS, without differences in NRS pain scores after spinal fusion in a chronic pain surgical cohort. Given these effects, patients with chronic pain may disproportionately benefit from ESPBs for spine surgery.