AIM: This study aimed to evaluate the impact of injectable nicotinic acid as adjuvant therapy on microcirculatory perfusion and digit survival rate after digital replantation.

METHODS: This single-center retrospective cohort study included 200 patients who underwent digital replantation. Based on the treatment regimen, patients were divided into two groups: the nicotinic acid group (n = 102) and the control group (n = 98). The primary outcome was the relative perfusion ratio (PU ratio), calculated by normalizing the perfusion value of the replanted digit to that of an intact and uninjured reference digit from the same patient, measured using a laser Doppler flowmeter. Secondary outcomes included the incidence of vascular crisis, digit survival rate, postoperative hospital stay, and adverse reactions.

RESULTS: On postoperative day 1, the perfusion ratio did not differ between the two groups. However, on postoperative days 3, 5, and 7, the perfusion ratios in the nicotinic acid group were significantly higher than those in the control group (all p < 0.001). In the nicotinic acid group, the total incidence of vascular crisis was significantly lower (p = 0.029), and the digit survival rate was significantly higher (p = 0.030), along with shorter postoperative hospital stay compared with the control group (p < 0.001). Subgroup analysis indicated that the therapeutic benefit of nicotinic acid was particularly pronounced in the subgroup with more severe “crush/avulsion” injuries. The incidence of facial flushing was higher in the nicotinic acid group (p < 0.001).

CONCLUSIONS: Adjuvant use of injectable nicotinic acid, in addition to conventional therapy, was associated with improved microcirculatory perfusion, reduced incidence of vascular crisis, and increased digit survival rate. The treatment was generally well tolerated with no serious safety concerns identified. Due to the retrospective and non-randomized nature of this study, these findings should be interpreted as associations rather than definitive treatment effects.