Background: Multiple studies have shown that perineural dexamethasone improves
postoperative analgesia. However, some studies have shown minimal benefit, and have raised
concerns regarding adverse physio-chemical effects of perineural dexamethasone. Furthermore,
there is a paucity of studies wherein control (IV) dexamethasone was considered.
Objective: The purpose of this meta-analysis was to evaluate the effectiveness of different
concentrations of perineural dexamethasone injection on postoperative analgesia, as well as
complications from its use for brachial plexus blocks.
Methods: A systematic literature search was conducted using the Cochrane Central Registry
of Controlled Trials, PubMed, and Scopus. Trials comparing control and local dexamethasonetreated groups, and those which reported duration of analgesia and/or pain scores/opioid
consumptions were selected. Meta-analysis was performed using the Review Manager (RevMan)
software 5.1.
Results: Fourteen studies consisting of a total of 1,022 patients were included. Perineural
dexamethasone significantly prolonged the duration of postoperative analgesia in patients
receiving both low-dose (4 – 5 mg) [SMD 2.41 (95% CI: 1.47, 3.35 P = 0<0.00001) I2
= 82%],
and higher-doses (8 – 10 mg) [SMD 4.46 (95% CI 3.54, 5.38 P < 0.00001) I2
= 94%]. However,
the duration of motor block was also prolonged [SMD 2.52 (95% CI: 1.06, 3.98 P = 0.0007) I2
= 97%] and dexamethasone delayed latency of onset of sensory [SMD -0.49 (95% CI: -0.89,
-0.09 P = 0.02) I2
= 76%] and motor [SMD -0.56 (95% CI: -1.13, 0.00 P = 0.05) I2
= 87%]
blocks. Postoperative pain scores were improved at both 24 hours [SMD -1.46 (95% CI: -2.43,
-0.50 P = 0.003) I2
= 95%] and 48 hours [SMD -1.20 (95% CI: -2.26, -0.13 P = 0.03) I2
= 95%]
in dexamethasone-treated groups, whereas opioid consumption was reduced only at 48 hours
[SMD -2.97 (95% CI: -4.17, -1.76 P < 0.00001) I2
= 88%]. Complications were comparable
between control and dexamethasone-adjuvant groups, except for the excessively prolonged
nerve block that was observed predominantly in the dexamethasone-adjuvant group.
Limitations: The limitations include different definitions used for the measurements of certain
parameters such as the duration of analgesia and duration of motor block, number of studies
assessing certain parameters having high heterogeneity, and varying types of local anesthetics
used in various studies.
Conclusions: Perineural dexamethasone addition to local anesthetic solutions significantly
improved postoperative pain in brachial plexus block without increasing complications.
However, perineural adjuvant dexamethasone delayed the onset of sensory and motor block,
and prolonged the duration of motor block. Smaller doses of dexamethasone (4 – 5 mg) were
as effective as higher doses (8 – 10 mg).
Key words: Dexamethasone, perineural, brachial plexus block, postoperative pain, metaanalysis, systematic review