Assessment of the effect of tube type on the cellular composition of centrifuged plasma and the rate of wound healing after surgical treatment of anal fissure combined with platelet-rich plasma injection

Vollständiger Abstract

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OBJECTIVE: the aim of this study is the effect of PRP application on the outcomes of chronic anal fissure treatment and to analyze the factors associated with the rate of anoderm defect epithelialization. PATIENTS AND METHODS: a single-center prospective randomized controlled trial (NCT07268261) was conducted from September 2023 to November 2025. We compared the outcomes of fissure excision (FE) combined with botulinum toxin type A (BTA) injection at a dose of 40 units and platelet-rich plasma injection (FE+BTA+PRP - study group) versus FE combined with BTA (FE+BTA - control group). After applying the exclusion criteria, 125 patients were included in the final analysis: 60 in the study group and 65 in the control group. Cellular composition of plasma was assessed using a hematology analyzer in 51 (85.0%) of 60 patients in the study group; among them, 29 patients underwent blood collection in two-component tubes (Subgroup A), and 22 patients underwent collection in single-component tubes (Subgroup B). The comparative analysis included assessment of wound epithelialization rate on 15, 30, 45 and 60 postoperative days, analgesic requirements, quality of life according to the SF-36 scale, platelet and leukocyte concentrations in PRP, as well as ROC analysis of the prognostic significance of the platelet profile. RESULTS: on the 60th day, the rate of postoperative wound healing was comparable in both groups, up to 43/60 (71.7%; 95% confidence interval [CI]: 58.6–82.5) cases in the FE+BTA+PRP group and 47/65 (72.3%; 95% CI: 59.8–82.7) cases in the FE+BTA group (p=0.936); on the 15th day, postoperative wound epithelialization was not observed in any patient; on the 30th day, wound healing occurred in 11/60 (18.3%) patients in the FE+BTA+PRP group and in none in the FE+BTA group (p=0.0003); on the 45th day — in 18/60 (30.0%) versus 3/65 (4.6%) patients (p=0.0001), respectively. The rates of wound healing depending on the type of tubes used on the 60th day postoperativ were comparable: in subgroup A (using two-component tubes), healing was observed in 21/29 (72.4%) cases, and in subgroup B (using single-component tubes) - in 16/22 (72.7%) cases; on the 30th day, epithelialization occurred in 11/29 (37.9%) cases in subgroup A and in none in subgroup B (0/22; 0%) (p=0.01). By 45th day the rate of postoperative wound healing increased in both subgroups: up to 51.7% (15/29 cases) with usage of two-component tubes and to 13.6% (3/22 cases) - with single-component tubes (p=0.007). A significant reduction in analgesic requirements and improvement in quality of life were noted in the study group. After centrifugation, the platelet level in two-component tubes was 397 × 10³/μL (346; 481), which was statistically significantly higher compared to single-component tubes at 239 × 10³/μL (106; 374) (p=0.001). The factor that statistically significantly increased the odds of epithelialization in univariate logistic regression analysis was the platelet level on the 30th day (OR=1.01; 95% CI: 1.00–1.02; p=0.008) and on the 45th day (OR=1.01; 95% CI: 1.00–1.01; p=0.007). The ROC analysis confirmed that a platelet concentration ≥452×10⁹/L in PRP is a statistically significant predictor of postoperative wound epithelialization time (p=0.001). CONCLUSION: intraoperative administration of low-leukocyte PRP in the surgical treatment of chronic anal fissure significantly accelerates postoperative wound epithelialization, reduces pain syndrome, and improves patients' quality of life. To optimize healing time, it is preferabli to achieve a platelet concentration in PRP of at least 452 × 10⁹/L.