Use of adjuvants in the prevention of rebound pain in patients with combat-related trauma: a prospective pilot study

Rebound pain (RP) is a sharp exacerbation of post-operative pain that occurs after the resolution of a peripheral nerve block (PNB). It is reported in 30–60 % of patients following single-injection regional blocks, particularly after orthopedic and traumatic surgeries. In patients with combat-related injuries, rebound pain is of particular clinical concern as it can complicate rehabilitation, reduce pain tolerance, and increase the risk of neuropathic pain development. The aim of this prospective pilot study was to evaluate the effectiveness of dexamethasone as an adjuvant to a single-shot PNB in patients with combat-related limb injuries. A total of 74 male patients aged 22–45 (mean of 30.8 ± 4.7) years were enrolled and divided into two groups. Group 1 (n = 36) received a single-shot bupivacaine block (1.5–2 mg/kg). In group 2 (n = 38), bupivacaine was combined with 2 mg of dexamethasone. Pain intensity was assessed using the Visual Analogue Scale (VAS) at 6 and 12 hours post-block. At 12 hours, the mean VAS score in group 1 was 6.1 compared to 4.2 in group 2. The proportion of patients experiencing pain ≥ 7 at any time point was 30.6 % (11 of 36) in group 1 versus 13.1 % (5 of 38) in group 2. Notably, only one patient (2.6 %) in group 2 reported a VAS score of ≥ 7 at 12 hours, indicating a significantly lower severity of RP. In group 2, DN4 assessment was performed additionally on day 14. 89.4 % of patients (34 of 38) had a DN4 score < 4, suggesting the absence of neuropathic pain, and 10.6 % (4 people) had an increased risk (DN4 scores ≥ 4). The mean DN4 score was 2.1 ± 0.9, reflecting mild neuropathic symptoms even in positive cases. The results demonstrate that adding dexamethasone to a local anesthetic in single-shot nerve blocks significantly reduces the intensity of rebound pain, the proportion of severe pain cases, and the risk of neuropathic progression. The biological rationale of dexamethasone use includes its anti-inflammatory effects, membrane stabilization, reduction of peripheral sensitization, and potential to prolong local analgesia. Despite certain limitations (small sample size, absence of DN4 data in group 1), this study provides encouraging findings that support further randomized trials invol­ving larger cohorts, catheter-based techniques, multimodal analgesia, and alternative adjuvants.