51st Annual Regional Anesthesiology and Acute Pain Medicine Meeting

Background:

Complex spine surgery is associated with:

•Severe postoperative pain

•High opioid requirements

•Prolonged hospital length of stay (LOS)

Using two or more NMDA antagonists may produce synergistic opioid-sparing effects by:

•Reducing central sensitization

•Decreasing opioid tolerance and hyperalgesia

Evidence supporting dual NMDA antagonist (D-NMDA) strategies is emerging but remains limited in real-world practice.

Objective:

To evaluate whether an intraoperative D-NMDA antagonist regimen for complex spine surgery is associated with:

•Reduced postoperative opioid consumption

•Shorter hospital length of stay

Methods:

Study Design

Single-institution retrospective cohort from

January 2024 – January 2026

Population

Adult patients undergoing elective complex spine surgery, defined as:

•≥6 vertebral levels fused or

•Operative duration ≥ 6 hours or

•Designated complex deformity procedures

Exposure

D-NMDA regimen:

•Intravenous methadone prior to incision

AND

•≥1 additional NMDA-modulating agent:

•Ketamine, lidocaine, or magnesium sulfate infusion

Primary Outcomes

•Total opioid consumption on postoperative day 3 (MME)

•Hospital length of stay

Discussion:

1.D-NMDA regimen was associated with:

•Marked reductions in opioid use

•Shorter hospital length of stay

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2.Opioid reduction persisted into the late postoperative period, suggesting improved analgesic durability.

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3.Findings align with prior studies supporting ketamine-based multimodal strategies.

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4.Benefits observed without increased respiratory or opioid-related complications

Safety and Recovery Outcomes

No difference in:

•PACU length of stay

•PCA duration

•Postoperative ketamine duration

•Antiemetic use

•Naloxone administration

Limitations

1.Retrospective design

2.Small exposed cohort (n = 18)

3.Potential for unmeasured confounders

4.Single-center study

Conslusions:

A D-NMDA antagonist regimen in complex spine surgery:

•Significantly reduced postoperative opioid requirements

•Associated with shorter hospital length of stay

•No increase in opioid-related adverse events

These findings support continued protocolization and prospective evaluation of D-NMDA strategies within enhanced recovery pathways.

References

1. Chou R, Gordon DB, de Leon-Casasola OA, et al. Management of postoperative pain: A clinical practice guideline from the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists’ Committee on Regional Anesthesia, Executive Committee, and Administrative Council. J Pain. 2016;17(2):131-157. doi:10.1016/j.jpain.2015.12.008

2. Corley JA, Charalambous LT, Mehta VA, Wang TY, Abdelgadir J, Than KD, Abd-El-Barr MM, Goodwin CR, Shaffrey CI, Karikari IO. Perioperative pain management for elective spine surgery: opioid use and multimodal strategies. World Neurosurg. 2022;162:118-125.e1. doi:10.1016/j.wneu.2022.03.084

3. De Oliveira GS, Jr., Castro-Alves LJ, Khan JH, McCarthy RJ. Perioperative systemic magnesium to minimize postoperative pain: a meta-analysis of randomized controlled trials. Anesthesiology. 2013;119(1):178–90.

4. Loftus RW, Yeager MP, Clark JA, Brown JR, Abdu WA, Sengupta DK, Beach ML. Intraoperative ketamine reduces perioperative opiate consumption in opiate-dependent patients with chronic back pain undergoing back surgery. Anesthesiology. 2010;113(3):639-646. doi:10.1097/ALN.0b013e3181e90914

5. Murphy GS, Avram MJ, Greenberg SB, Benson J, Bilimoria S, Maher CE, Teister K, Szokol JW. Perioperative methadone and ketamine for postoperative pain control in spinal surgical patients: A randomized, double-blind, placebo-controlled trial. Anesthesiology. 2021;134(5):697-708. doi:10.1097/ALN.0000000000003743

51st Annual Regional Anesthesiology and Acute Pain Medicine Meeting

Double NMDA Antagonist Regimen for Elective Complex Spine Surgery Results in Reduced Opioid Burden and Length of Stay

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