The authors hypothesized that both perineural and systemic dexamethasone as adjuncts to bupivacaine increase the duration of an ulnar nerve block compared with bupivacaine alone, and that systemic dexamethasone is noninferior to perineural dexamethasone.


The authors performed bilateral ulnar nerve blocks with 3 ml bupivacaine 5 mg/ml in 16 healthy volunteers on two trial days. According to randomization, subjects received adjunct treatment with 1 ml dexamethasone 4 mg/ml + 1 ml of saline (perineural condition) in one arm and 2 ml saline in the other arm (systemic condition, through absorption and redistribution of the contralaterally administered perineural dexamethasone) on one trial day; and 2 ml saline in one arm (placebo condition) and 2 ml of lidocaine in the other arm (lidocaine condition) on the other trial day. The primary outcome was the duration of the sensory nerve block assessed by temperature discrimination.


Mean sensory block duration was 706 ± 94 min for the perineural condition, 677 ± 112 min for the systemic condition, and 640 ± 121 min for the placebo condition. The duration of the sensory nerve block was greater with perineural dexamethasone versus placebo (mean difference 66 min (95% CI, 23 to 108). Block duration was similar between systemic dexamethasone and placebo (mean difference 36 min; 95% CI, –30 to 103).


Perineural dexamethasone as an adjunct to bupivacaine in healthy volunteers resulted in a greater duration of an ulnar nerve block when compared with placebo. Systemic dexamethasone resulted in a similar duration as placebo.

Editor’s Perspective
What We Already Know about This Topic
  • Perineural dexamethasone may prolong the duration of postoperative analgesia afforded by a regional anesthetic
  • Other studies have suggested that intravenous dexamethasone has analgesic properties that could contribute to regional anesthetic duration
What This Article Tells Us That Is New
  • When carefully controlling for the effects of systemic dexamethasone, perineural administered dexamethasone prolongs a peripheral nerve block
  • Under carefully controlled conditions in healthy volunteers, systemic dexamethasone does not appear to prolong nerve block duration