Intraoperative Ketamine versus Micro-Dose Morphine Infusion during Thoracolumbar Laminectomy: Pain Trajectory and C-Reactive Protein Response in a Randomized Trial

Abstract

Background. Pain after spine surgery is often poorly controlled, and whether intraoperative ketamine also attenuates the early inflammatory response is uncertain.

Objective. To compare intraoperative ketamine with a micro-dose morphine infusion for early postoperative pain and high-sensitivity C-reactive protein (hs-CRP) after thoracolumbar laminectomy, in a corrected re-analysis of a published trial.

Methods. In this double-blind randomized trial at Dr. Moewardi Regional General Hospital, Surakarta, Indonesia, 24 adults undergoing elective thoracolumbar decompressive laminectomy received ketamine 10 µg/kg/min or morphine 10 µg/kg/h (n=12 each) from intubation to skin closure. Outcomes were visual analog scale (VAS) pain at 6 and 12 hours and hs-CRP before and 6 hours after surgery, analyzed with 95% confidence intervals (CI) and baseline-adjusted analysis of covariance.

Results. At 6 hours, VAS was lower with ketamine (2.33 vs 3.83; difference −1.50, 95% CI −2.28 to −0.72; Holm-adjusted p=0.001) but not at 12 hours (5.25 vs 5.67; −0.42, −1.32 to 0.49; p=0.660), when 20 of 24 patients (83.3%) scored above 4. hs-CRP rose in every patient; adjusted for baseline, the 6-hour value was 1.28 mg/L lower with ketamine (95% CI 0.53 to 2.03; Holm-adjusted p=0.006), an effect not explained by the imbalance in duration of surgery. Rescue analgesia did not differ (2/12 vs 3/12; p=1.000).

Conclusion. Compared with a micro-dose morphine infusion, intraoperative ketamine improved analgesia for the first postoperative hours and attenuated the early hs-CRP rise, but neither regimen controlled pain at 12 hours; analgesia must extend beyond the operating room.