Background: Since anal fistulas can be challenging to treat; numerous innovative treatments have been proposed, including stem cell therapy. This systematic review aimed to assess pooled rates of fistula healing and adverse events associated with stem cell treatment.

Methods: In this PRISMA-compliant systematic review we searched PubMed and Scopus for observational and randomized studies reporting outcomes of stem cell treatment for anal fistulas. The main outcome measures were successful healing and adverse effects of stem cell therapy.

Results: In total, 43 studies incorporating 1160 patients (53.6% male) were included. Underlying fistula etiologies were Crohn's disease (30 studies) and cryptoglandular disease (12 studies). The main origin of stem cells was from adipose tissue (34 studies) or bone marrow (6 studies). The median follow-up duration was 12 months. The combined overall pooled healing rate was 58.1% (95% confidence interval (CI) 51.5-64.7%). The pooled healing rate for Crohn's fistulas was 60.4% (95% CI 54.7-66.2%) with adipose-derived stem cells and 63.6% (95% CI 49.4-77.7%) with bone-marrow-derived cells. The pooled healing rate for cryptoglandular fistulas was 53.8% (95% CI 35.5-72.2%) with adipose-derived stem cells. The pooled complication rate was 37.3% (95% CI 27.1-47.5%). Stem cells were associated with higher odds of anal fistula healing (odds ratio (OR): 1.81, p = 0.003) and similar odds of complications (OR: 1, p = 0.986) compared with controls.

Conclusions: Stem cell treatment of anal fistulas was associated with promising results. The healing rate in Crohn's anal fistulas was higher than in cryptoglandular fistulas. Bone-marrow-derived stem cells were associated with marginally better outcomes than were adipose-derived cells. This finding suggests that the autoimmune inflammatory etiology of Crohn's disease may respond better to autologous myoblasts than does the infectious etiology of cryptoglandular fistulas.

Keywords: Adverse effects; Anal fistulas; Healing; Stem cells; Systematic review.

© 2025. The Author(s).

背景： 由于肛瘘的治疗具有挑战性，因此提出了许多创新治疗方法，包括干细胞疗法。本系统综述旨在评估与干细胞治疗相关的瘘管愈合率和不良事件的发生率。

方法： 在这项符合PRISMA标准的系统综述中，我们搜索了PubMed和Scopus数据库，寻找有关肛瘘干细胞治疗结果的观察性和随机化研究。主要结局指标是干细胞疗法的成功愈合率和不良反应。

结果： 总共纳入43项研究，涉及1160名患者（53.6%为男性）。基础肛瘘病因包括克罗恩病（30项研究）和隐窝腺疾病（12项研究）。干细胞的主要来源是脂肪组织（34项研究）或骨髓（6项研究）。中位随访时间为12个月。总体合并愈合率为58.1%（95%置信区间为51.5%-64.7%）。克罗恩病瘘管的合并愈合率为60.4%（95%置信区间为54.7%-66.2%），使用脂肪来源干细胞，而骨髓源干细胞的愈合率则为63.6%（95%置信区间为49.4%-77.7%）。隐窝腺瘘管的合并愈合率为53.8%（95%置信区间为35.5%-72.2%），使用脂肪来源干细胞。总的并发症发生率为37.3%（95%置信区间为27.1%-47.5%）。与对照组相比，干细胞治疗的肛瘘愈合几率较高（比值比(OR): 1.81, p = 0.003），并且并发症的发生几率相似（OR: 1, p = 0.986）。

结论： 干细胞治疗肛瘘显示出令人鼓舞的结果。克罗恩病肛瘘的愈合率高于隐窝腺性瘘管。与脂肪来源细胞相比，骨髓源干细胞的相关结局略好一些。这一发现表明，自身免疫炎症性病因的克罗恩病可能比感染性病因的隐窝腺瘘对自体肌成纤维细胞有更好的反应。

关键词： 不良事件；肛瘘；愈合；干细胞；系统综述。