Ultrasound-guided hydrodissection combined with acupotomy for moderate-to-severe Carpal tunnel syndrome: electrophysiological and ultrasonographic outcomes and their potential relationship to neuroinflammatory attenuation.

BACKGROUND: Carpal tunnel syndrome (CTS) is a common compression neuropathy in which sustained median nerve ischemia drives progressive neuroinflammation, structural remodeling of the transverse carpal ligament (TCL), and functional nerve impairment. Current interventions typically address either the inflammatory or structural component of the disease, but rarely both simultaneously, and clinical evidence for combined approaches in moderate-to-severe CTS remains limited. OBJECTIVE: To evaluate the clinical efficacy of ultrasound-guided hydrodissection combined with acupotomy in moderate-to-severe CTS, and to explore whether improvements in electrophysiological and ultrasonographic outcomes are consistent with attenuation of neuroinflammatory processes, while acknowledging that direct molecular confirmation was not performed in this study. METHODS: This single-center retrospective cohort study enrolled 100 patients with moderate-to-severe CTS (February 2019-February 2025). The dual-axis group (n = 49) received hydrodissection combined with acupotomy; the single-axis group (n = 51) received hydrodissection alone. Primary outcomes were BCTQ-SSS and BCTQ-FSS scores; secondary outcomes included VAS, nerve electrophysiological biomarkers (SCV, DML, CMAP), ultrasonographic biomarkers (nerve CSA, TCL thickness), clinical efficacy grading, and adverse events at baseline, 1 week, 1 month, 3 months, and 6 months. RESULTS: Both groups improved significantly from baseline (P < 0.05). The dual-axis group demonstrated significantly superior BCTQ-SSS, BCTQ-FSS, and VAS scores from 1 month onward (all Bonferroni-corrected P < 0.001). At 6 months, the dual-axis group showed markedly superior electrophysiological indicators of nerve functional recovery (SCV: 42.36 ± 4.87 vs. 38.92 ± 5.23 m/s; DML: 4.12 ± 0.65 vs. 4.58 ± 0.71 ms; CMAP: 7.85 ± 1.52 vs. 6.92 ± 1.64 mV; all P < 0.05) and greater reduction in ultrasonographic biomarkers of inflammatory edema (CSA: 10.35 ± 1.86 vs. 11.82 ± 2.14 mm2; TCL: 2.15 ± 0.38 vs. 2.68 ± 0.42 mm; all P < 0.001). The overall response rate was 93.9% vs. 80.4% (P = 0.031). No serious adverse events occurred. CONCLUSION: Ultrasound-guided hydrodissection combined with acupotomy demonstrated superior clinical, electrophysiological, and ultrasonographic outcomes compared with hydrodissection alone in moderate-to-severe CTS. Improvements in nerve conduction velocity, distal motor latency, CMAP amplitude, and median nerve cross-sectional area are consistent with, and may reflect, attenuation of underlying neuroinflammatory processes; however, direct molecular evidence for such a mechanistic connection was not obtained in this study and the association remains a hypothesis requiring prospective validation. These findings support the combined approach as a minimally invasive option for patients who are unable or unwilling to undergo surgical decompression, pending confirmation by prospective randomized trials with a surgical comparator arm.