Abstract: Surgical treatment of anal fistulas faces the dual challenge of achieving wound healing while preserving anal function. High or complex anal fistulas represent a closed-space, non-functional cavity within the perianal musculature, predominantly occurring in the posterior deep space of the anal sphincter complex. Effective management requires complete opening of this space and ensuring adequate drainage to control infection and promote healing. Traditional fistulotomy with seton placement is primarily suitable for simple fistulas, but its application in complex cases often results in high incontinence rates. In the era of sphincter-preserving techniques, surgeons must select appropriate surgical approaches that prioritize the anatomical integrity of the anal sphincter system. Current literature and guidelines propose multiple therapeutic options, including mucosal advancement flap （MAF）, laser therapy, video-assisted anal fistula treatment （VAAFT）, ligation of intersphincteric fistula tract （LIFT）, over-the-scope clip closure （OTSC）, and radiofrequency ablation （RAF）, however, up to the present moment, no single method has demonstrated substantial and promising potential. The transanal opening of intersphincteric space （TROPIS） technique, introduced in recent years, offers a unique approach. Instead of closing the internal fistula opening, TROPIS enlarges it by incising the fistula tract along the intersphincteric plane. This method fully preserves the external anal sphincter （EAS） and facilitates secondary healing through sustained drainage. Transanal opening of intersphincteric space （TROPIS） is a novel technique developed in recent years for high or complex anal fistulas. Instead of closing the internal fistula opening, it enlarges the opening by incising the fistula tract along the intersphincteric plane, completely preserving the external anal sphincter （EAS） and allowing secondary healing through drainage. First reported in 2017, TROPIS has demonstrated good efficacy and safety in treating complex high anal fistulas and is gaining wider adoption. This article reviews the clinical outcomes and future prospects of TROPIS.

Key words: transanal opening of intersphincteric space, high and complex anal fistulas, external anal sphincter, progress

摘要： 肛瘘的外科治疗面临着同时兼顾创面愈合和肛门功能保护的问题。高位或复杂性肛瘘相当于肛门周围肌肉间的封闭死腔,多数发生于肛管括约肌后深间隙,只有充分打开此间隙及引流通畅,感染才可以控制,创面得以愈合。传统切开挂线术仅适用于单纯或简单的肛瘘,对于复杂肛瘘,愈合往往伴随着高大便失禁率。在保留括约肌技术的时代,在保证肛门括约肌系统的解剖结构和完整性的前提下,如何选择合适的手术方法来处理瘘管,文献和指南提供了多种治疗方法,如黏膜推进瓣术（MAF）、激光治疗、肛瘘镜辅助下肛瘘治疗术（VAAFT）、括约肌间瘘管结扎术（LIFT）、经内镜吻合夹闭合术（OTSC）、肛瘘射频消融术（RAF）等,但目前尚无一种方法展现出巨大的潜力。经经肛括约肌间切开术（TROPIS）是近几年出现的一种独特术式,它不封闭瘘管内口,而是通过在括约肌间平面切开瘘管来扩大内口,肛门外括约肌（EAS）完全保留,通过引流使创口二期愈合。TROPIS术式于2017年首次报道,在治疗高位复杂性肛瘘中具有良好的有效性和安全性,并得到推广。本文对TROPIS的应用效果和前景进行综述。

关键词: 经经肛括约肌间切开术, 复杂性肛瘘, 外括约肌, 进展