Pre-emptive infiltration with betamethasone and ropivacaine for postoperative pain in laminoplasty and laminectomy (PRE-EASE): a prospective randomized controlled trial

Background: Postoperative pain after laminoplasty and laminectomy occurs partially from local trauma of the paraspinal tissue. Finding a multimodal analgesic cocktail to enhance the duration and effect of local infiltration analgesia is crucial. Because of the rapid onset and long duration of action of betamethasone, the authors hypothesized that, a pre-emptive multimodal infiltration regimen of betamethasone and ropivacaine reduces pain scores and opioid demand, and improves patient satisfaction following laminoplasty and laminectomy.Materials and methods: This prospective, randomized, open-label, blinded endpoint study was conducted between 1 September 2021 and 3 June 2022, and included patients between the ages of 18 and 64 scheduled for elective laminoplasty or laminectomy under general anesthesia, with American Society of Anesthesiologists classification I/II. One hundred sixteen patients were randomly assigned to either the BR (Betamethasone-Ropivacaine) group or the R (Ropivacaine) group in a 1:1 ratio. Each group received pre-emptive infiltration of a total of 10 ml study solution into each level. Every 30 ml of study solution composed of 0.5 ml of betamethasone plus 14.5 ml of saline and 15 ml of 1% ropivacaine for the BR group, and 15 ml of 1% ropivacaine added to 15 ml of saline for the R group. Infiltration of epidural space and intrathecal space were avoided and the spinous process, transverse process, facet joints, and lamina were injected, along with paravertebral muscles and subcutaneous tissue. Cumulative 48 h postoperative butorphanol consumption via PCA (Patient-controlled analgesia) was the primary outcome. Intention-to-treat (ITT) principle was used for primary analysis.Results: Baseline characteristics were identical in both groups (P>0.05). The cumulative 48 h postoperative butorphanol consumption via PCA was 3.0 +/- 1.4 mg in the BR group (n=58), and 7.1 +/- 1.2 mg in the R group (n=58) (P<0.001). Overall cumulative opioid demand was lower at different time intervals in the BR group (P<0.001), along with the estimated median time of first analgesia demand via PCA (3.3 h in the BR group and 1.6 h in the R group). The visual analog scale (VAS) score at movement and rest were also significantly lower until 3 months and 6 weeks, respectively. No side effects or adverse events associated with the intervention were observed in this study.Conclusions: Pre-emptive analgesia with betamethasone and ropivacaine provides better postoperative pain management following laminoplasty and laminectomy, compared to ropivacaine alone. This is an effective technique worthy of further evaluation.