Perfusion Enhancement via Continuous Brachial Plexus Block to Prevent Vascular Insufficiency in Replanted Digits: A Prospective, Randomized Controlled Trial

<b>Background/Objectives:</b> Pain-induced vasoconstriction and thrombosis cause vascular insufficiency, a major etiology of early necrosis in replanted digits. While systemic intravenous analgesia (SIVA) carries significant side effects, continuous brachial plexus block (CBPB) provides analgesia with vasodilation. Amidst uncertainties regarding distal vascular recanalization and sympathetic denervation, whether CBPB's hemodynamic effects translate into improved perfusion and outcomes in replanted digits remains unknown. This randomized controlled trial compared the effects of CBPB versus SIVA on digit perfusion, vascular insufficiency, and survival rates post-replantation. <b>Methods:</b> After screening 113 patients, 55 patients (71 digits) were ultimately randomized and analyzed: the CBPB group (<i>n</i> = 27, 36 digits) received 0.2% ropivacaine infusion at 5 mL/h; the SIVA group (<i>n</i> = 28, 35 digits) received intravenous parecoxib 20 mg twice daily with supplemental tramadol for visual analog scale (VAS) scores > 3. The primary outcome was digital skin temperature trajectory measured at 0, 12, 24, 36, and 48 h postoperatively. Secondary outcomes included Doppler-quantified combined volumetric flow rate of the radial and ulnar arteries (RA-UA VFR) at identical timepoints, VAS scores, vascular insufficiency incidence, and 7-day digit survival. <b>Results:</b> CBPB significantly enhanced perfusion in replanted digits at all postoperative timepoints, with digital skin temperature peaking at 48 h (32 ± 1.6 °C vs. 31 ± 1.1 °C; <i>p</i> < 0.001) and RA-UA VFR peaking at 24 h (4.0 ± 0.83 vs. 1.8 ± 0.51 mL/s; <i>p</i> < 0.001) versus SIVA. Concurrently, CBPB provided superior analgesia (VAS 0.52 ± 0.51 vs. 1.9 ± 1.0; <i>p</i> < 0.001) and significantly reduced 48-h vascular insufficiency incidence (8.3% vs. 29%; <i>p</i> = 0.028). No significant difference was observed in seven-day survival rates between groups (97% vs. 91%; <i>p</i> = 0.329). <b>Conclusions:</b> CBPB significantly enhanced perfusion in replanted digits and reduced the incidence of vascular insufficiency, despite not conferring additional survival benefits.