Background: Bilateral superficial cervical plexus block (BSCPB) is used within multimodal analgesia for thyroid surgery, and dexamethasone has been studied as an adjunct intended to prolong block-related analgesia. Because this study had no comparator group, its findings are interpreted as descriptive outcomes of a combined anesthetic and regional-analgesia protocol rather than as evidence of dexamethasone efficacy.

Objective: To describe 24-hour postoperative pain, rescue-analgesic requirements, and reported block-related complications in adults undergoing thyroid surgery who received ultrasound-guided BSCPB with bupivacaine and perineural dexamethasone.

Methods: This prospective single-center case series included 12 adults from a source population of 21 patients scheduled for thyroid surgery at Hospital Ana Francisca Pérez de León II between January and June 2025. All underwent general anesthesia followed by ultrasound-guided bilateral superficial cervical plexus block using a 10-mL preparation containing bupivacaine 25 mg (final concentration 0.25%) and dexamethasone 4 mg; the source thesis did not specify the exact volume injected per side. Pain was assessed on a 0–10 numerical rating scale at 30 minutes, 2 hours, 12 hours, and 24 hours. Protocol-defined analgesic failure was a score ≥4 at a scheduled assessment or a patient request for rescue medication; ketorolac 30 mg sublingually was the rescue regimen.

Results: All 12 patients were ASA physical status II. At 30 minutes and 2 hours, 1 patient (8.3%) reported no pain and 11 (91.7%) reported mild pain (scores 1–3). At 12 and 24 hours, all 12 patients (100%) had mild pain; no moderate or severe pain was reported at any scheduled assessment. No patient met the predefined failure criterion or required rescue analgesia (12/12; post hoc exact 95% CI, 73.5%–100%). No block-related complication was reported in the aggregated source results (0/12; post hoc exact 95% CI, 0%–26.5%).

Conclusions: Favorable 24-hour pain and rescue-analgesia outcomes were observed after the combined general-anesthesia and BSCPB protocol. The small single-arm sample, systemic analgesic cointerventions, incomplete reporting of several planned outcomes, and absence of a comparator prevent causal attribution to perineural dexamethasone or definitive conclusions regarding safety.