Effect of the intravenous acetaminophen clinical pathway on postoperative analgesia in spinal fusion surgery

Post spinal-fusion surgery pain levels are high, posing challenges for pain management. We introduced around-the-clock (ATC) administration of intravenous acetaminophen in the clinical pathway for spinal-fusion surgery. This single-center, retrospective observational study investigated effects of its introduction on postoperative pain levels and recovery adjusting for background variables. Adult patients who underwent elective spinal-fusion surgery were categorized into pre- and post-groups based on the timing of ATC acetaminophen introduction. The primary endpoint was the numerical rating scale (NRS) score at rest in the morning of the first postoperative day (POD). Secondary endpoints were NRS scores on POD1-3, rescue analgesic use, postoperative nausea and vomiting within 48 h, food intake, ambulation, and hospitalization length. The pre- and post-groups included 31 and 47 patients, respectively. The estimated means of NRS scores on POD1 were significantly lower in the post-group (1.21) than in the pre-group (3.91) (P < 0.0001). NRS scores until POD3 and number of rescue analgesics used were significantly lower in the post-group. There were no significant differences in the postoperative recovery endpoints, barring a trend toward shorter hospitalization in the post-group. In elective spinal-fusion surgery, the introduction of ATC intravenous acetaminophen into the clinical pathway improved postoperative analgesia.