Thirty patients undergoing surgery for neurosurgical lower-thoracic and lumbar spinal fusion were randomized to receive either an erector spinae block with opioid-based analgesia (ESPB; n=15) or opioid-based analgesia alone (n=15). The primary outcome of interest was morphine consumption measured using patient-controlled analgesia (PCA) at 48 hours. Secondary outcomes included fentanyl consumption, blood loss, pain on a Numeric Rating Scale (NRS), length of stay, and patient satisfaction. PCA consumption within the first 48 hours was significantly lower in the ESPB group compared to the opioid-based analgesia group alone. Intraoperative fentanyl, NRS pain until 36 hours, patient satisfaction, and PCA from 0-36 hours were significantly lower in the ESPB group compared to the control.