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Ultrasound-guided lateral pterygoid muscle block as an adjunct to multimodal analgesia for impacted third molar
Keisuke Nakazawa1, Shun Hoshino2, Ryota Tsukui2
1Department of Anesthesiology, Nihon University School of Medicine, Tokyo, Japan.
Background:
Ultrasound-guided lateral pterygoid muscle (LPM) block, a single-intramuscular-injection technique originally described for sagittal split ramus osteotomy, may offer a simplified regional analgesic option for dental surgery. However, its application as an adjunct to wound infiltration in impacted third molar extraction has not been reported.
Methods:
This retrospective two-center exploratory study included 48 consecutive patients who underwent impacted third molar extraction under general anesthesia between September and November 2025. All patients received standardized intraoperative multimodal analgesia (intravenous acetaminophen and dexamethasone) and wound local infiltration; the LPM group (n = 27) additionally received an ultrasound-guided LPM block with 10 ml of 0.25% levobupivacaine, whereas the NE group (n = 21) received wound infiltration alone. The primary outcome was the Numeric Rating Scale (NRS) score at rest 6 h postoperatively. Institutional and extraction-pattern imbalances were addressed using adjusted ordinal logistic regression sensitivity analyses.
Results:
The median NRS score at rest 6 h postoperatively was lower in the LPM group than in the NE group (0 [0, 2] vs. 3 [1.5, 4.0], P < 0.001). The institution- and extraction-pattern-adjusted ordinal logistic regression preserved the direction of the association (adjusted odds ratio 0.14, 95% confidence interval 0.04-0.48, P = 0.002). The recorded total volume of wound local anesthetic was similar between the groups (LPM 9.0 ml vs. NE 8.4 ml, P = 0.729). Lower NRS scores were also observed at 2 h and 21:00; differences resolved by the following morning. The median time to first rescue analgesia was 10 h in the LPM group versus 7 h in the NE group (log-rank P = 0.294). No complications directly attributable to the LPM block were documented during the recorded early postoperative observation window.
Conclusion:
An adjunctive ultrasound-guided LPM block was associated with lower recorded early postoperative pain scores after impacted third molar extraction. These hypothesis-generating findings require confirmation in the ongoing ALPINE randomized controlled trial (jRCT1031250592).
