To compare the incidence of rebound pain, postoperative analgesic effect, and opioid consumption after interscalene brachial plexus block (ISBPB) with intravenous or perineural dexamethasone in patients with rotator cuff injuries.

One hundred patients were randomly assigned into two groups according to the random number table method, to receive either intravenous dexamethasone (Ⅳ group, n=50) or perineural dexamethasone (PN group, n=50) during ISBPB. All the participants underwent ISBPB about 30 min before surgery. Patients in the Ⅳ group were administered with 20 ml ropivacaine at a concentration of 0.25% for ISBPB, and then injected with dexamethasone 1 ml (5 mg) intravenously. Patients in the PN group were administered with 20 ml mixture of ropivacaine 0.25% plus dexamethasone 5 mg, and then injected with 1 ml normal saline. The protocols of anesthesia induction and maintenance were exactly the same for the two groups. Demographic data and surgery-related data of the patients were collected. The observations in the two groups were as follows: the incidence of rebound pain, as well as its intensity and duration; the duration of brachial plexus block; the NRS pain scores at PACU and 6 h, 12 h, 24 h, 48 h, and 30 d postoperatively, including at rest and after movement; the initial time of requiring tramadol, and the total consumption of this rescue drug; the occurrence of sleep disturbance at the current night; the hospital stay and adverse reactions.

There were no significant differences between the two groups in demographic data and surgery-related data (P>0.05). Patients in the PN group had a lower incidence of rebound pain, lower NRS values at 12 h and 24 h postoperatively, and a lower incidence of sleep disturbance compared with those of the Ⅳ group (P<0.05). Patients in the PN group exhibited a longer duration of ISBPB and longer time to first tramadol requirement, as well as lower total consumption of tramadol within 48 hours compared with those of the Ⅳ group (P<0.05).

In rotator cuff repair surgery, compared with intravenous dexamethasone, preoperative ISBPB combined with perineural dexamethasone is able to reduce the incidence of rebound pain, the extent of postoperative pain, and the total consumption of analgesic within two days, delay the first time to require rescuing analgesic, and reduce the incidence of sleep disturbance.