Newer procedures need to demonstrate efficacy in high complex anal fistulas

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Ann Coloproctol. 2023;39(4):371-372
Publication date (electronic) : 2023 March 15
doi :
Department of Colorectal Surgery, Garg Fistula Research Institute, Panchkula, India
Correspondence to: Pankaj Garg, FASCRS Department of Colorectal Surgery, Garg Fistula Research Institute, 1042, Sector 15, Panchkula 134113, India Email:
Received 2022 December 9; Revised 2022 December 30; Accepted 2023 January 1.

Dear Editor,

I read with great interest the article by Lalhruaizela [1] highlighting his experience with endofistula laser ablation (EFLA) in anal fistulas. The author reported a primary success rate of 67.7% and a secondary (overall) success rate of 80% in a cohort of 31 anal fistula patients. However, there are a couple of questions and pertinent points that merit discussion according to our experiences.

The author included only primary, simple low uncomplicated fistulas in the study and excluded high complex fistulas [1]. However, it was not precisely defined which fistulas were categorized as simple and which ones as complex. One patient with a suprasphincteric fistula was also included in the study. Suprasphincteric fistulas are high complex fistulas and are categorized as grade III by Garg [2] and grade V by the St. James’s University Hospital [2] and Garg classifications [2, 3].

Low fistulas are defined as those involving less than one-third of the external anal sphincter [2]. It is an established fact that fistulotomy is the gold standard for managing low simple fistulas [3]. A success rate of 98% to 100% can be achieved in low fistulas with minimal risk to continence [3]. Therefore, the management of low simple fistulas is almost a settled issue. However, fistulotomy is contraindicated in high fistulas (fistulas involving more than one-third of the external anal sphincter) due to the high risk of incontinence [3]. Therefore, what is urgently needed is to find a sphincter-saving procedure in high fistulas that would not cause a significant deterioration in continence.

Several new sphincter-saving procedures have been advocated in the last decade. These include the anal fistula plug, video-assisted anal fistula treatment (VAAFT), over-the-scope clip (OTSC), the FiXcision device (A.M.I), fistula laser closure (FiLaC; Biolitec), and EFLA [3, 4]. These procedures are device-dependent, expensive, and require a learning curve [4]. The primary reason and intention behind the innovation of these sphincter-saving procedures were to find a safe (minimal risk to continence) and effective procedure for high fistulas. Incidentally, almost all studies published to date have demonstrated moderate efficacy of these device-driven procedures in low simple fistulas (40%–70%), for which fistulotomy offers 95% to 100% healing rates [3]. To date, no studies have analyzed the efficacy of these newer procedures in a cohort of exclusively high complex fistulas [3]. This raises a question regarding their utility and exact place in the management of anal fistulas. Could it be a case of aggressive marketing by device manufacturing companies, a possibility that cannot be ruled out?

The latest understanding in the pathophysiology of complex anal fistulas underlines the importance of adequately managing sepsis in the intersphincteric space [5]. It has been highlighted that sepsis in the fistula tract in the intersphincteric space is like an “abscess in a closed space” [5]. An abscess, anywhere in the body, is not cured by simple aspiration or antibiotics. It requires drainage of the abscess cavity and ensured drainage in the postoperative period to facilitate healing by secondary intention [3, 5]. Therefore, deroofing of the abscess cavity is performed to achieve drainage in the postoperative period. These time-tested, well-known principles of abscess management need careful consideration in the management of complex anal fistulas.

Most complex anal fistulas have a degree of an intersphincteric component (fistula tract in the intersphincteric space). It becomes pertinent to deal effectively with this “abscess in a closed space” (fistula tract in the intersphincteric space) [3, 5]. If the fistula tract in the intersphincteric space is not managed properly, as happens with the use of an anal fistula plug, VAAFT, OTSC clip, FiXcision, FiLaC, or EFLA, then the chances of recurrence are quite high [3, 5]. If a fistula tract in the intersphincteric space is deroofed into the ischiorectal fossa, the external anal sphincter would be damaged, leading to a deterioration in continence [6]. Therefore, the most convenient and safest way is deroofing a fistula tract in the intersphincteric space into the anal canal through the transanal route, as is done in the transanal opening of the intersphincteric space (TROPIS) technique [5, 7, 8]. Therefore, the success rate of TROPIS is quite high (90%) in high complex anal fistulas [5, 7, 8]. A recent meta-analysis highlighted that of all sphincter-preserving procedures, TROPIS had the highest cure rate [9]. Fistulectomy with primary sphincter reconstruction also excises the fistula tract in the intersphincteric space and thus has a high success rate in high fistulas. Although ligation of intersphincteric fistula tract (LIFT) addresses and opens the fistula tract in the intersphincteric space, it does not ensure continuous drainage in the postoperative period (by deroofing) [4]. Therefore, LIFT has a moderate success rate in high complex fistulas [4, 10].

In summary, proper management of the fistula tract in the intersphincteric space had been largely ignored in the management of anal fistulas, and the emphasis had been entirely on the closure of the internal opening and management of external tracts. The opening of the fistula tract in the intersphincteric space was limited to the drainage of high intersphincteric abscesses and this was never extended to the routine management of high complex anal fistulas. Once this gap was addressed by the development of the TROPIS procedure, the success rate jumped markedly, with no significant deterioration in continence.


Conflict of interest

No potential conflict of interest relevant to this article was reported.




1. Lalhruaizela S. Endofistula laser ablation of fistula-in-ano: a new minimally invasive technique for the treatment of fistula-in-ano. Ann Coloproctol 2022;38:301–6.
2. Garg P. Assessing validity of existing fistula-in-ano classifications in a cohort of 848 operated and MRI-assessed anal fistula patients: cohort study. Ann Med Surg (Lond) 2020;59:122–6.
3. Garg P, Sodhi SS, Garg N. Management of complex cryptoglandular anal fistula: challenges and solutions. Clin Exp Gastroenterol 2020;13:555–67.
4. Jayne DG, Scholefield J, Tolan D, Gray R, Senapati A, Hulme CT, et al. A multicenter randomized controlled trial comparing safety, efficacy, and cost-effectiveness of the surgisis anal fistula plug versus surgeon’s preference for transsphincteric fistula-in-ano: the FIAT trial. Ann Surg 2021;273:433–41.
5. Garg P, Kaur B, Menon GR. Transanal opening of the intersphincteric space: a novel sphincter-sparing procedure to treat 325 high complex anal fistulas with long-term follow-up. Colorectal Dis 2021;23:1213–24.
6. Garg P, Yagnik VD, Kaur B, Menon GR, Dawka S. Efficacy of Kegel exercises in preventing incontinence after partial division of internal anal sphincter during anal fistula surgery. World J Clin Cases 2022;10:6845–54.
7. Li YB, Chen JH, Wang MD, Fu J, Zhou BC, Li DG, et al. Transanal opening of intersphincteric space for fistula-in-ano. Am Surg 2022;88:1131–6.
8. Huang B, Wang X, Zhou D, Chen S, Li B, Wang Y, et al. Treating highly complex anal fistula with a new method of combined intraoperative endoanal ultrasonography (IOEAUS) and transanal opening of intersphincteric space (TROPIS). Wideochir Inne Tech Maloinwazyjne 2021;16:697–703.
9. Huang H, Ji L, Gu Y, Li Y, Xu S. Efficacy and safety of sphincter-preserving surgery in the treatment of complex anal fistula: a network meta-analysis. Front Surg 2022;9:825166.
10. Garg P. Comparison between recent sphincter-sparing procedures for complex anal fistulas-ligation of intersphincteric tract vs transanal opening of intersphincteric space. World J Gastrointest Surg 2022;14:374–82.

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