Gloria Zaffaroni interviews Professor Paolo Giamundo, Consultant Colorectal Surgeon, Policlinico di Monza (Italy) for ESCP's monthly topic: anal fistula.

The treatment of anal fistula remains a challenge for colorectal surgeons. Fistulotomy and fistulectomy have adequate healing rates and a low percentage of recurrence, but with the potential for faecal incontinence. For this reason, the latest research concentrates especially on sphincter-sparing procedures.

Fistula-tract laser closure (FiLaC) is a sphincter-saving technique using a radial emitting laser fiber to obliterate the fistula, with or without closing the internal opening.

Gloria Zaffaroni: Dear Professor Giamundo, thanks for the opportunity to talk and focus on FiLaC.

Which are the variables that influence the success rate of this procedure? Do you think there is a most important factor as the length of the fistula tract or the diameter?

Paolo Giamundo: There are many variables that need to be considered: fistula length, its diameter, the laser energy used, the placement of a loose seton or a loop drainage as a 'bridge' to the laser treatment; not to mention patient’s healing power in response to laser trigger effect.

In this regard, further studies on fistulas pathophysiological mechanisms may be helpful in shedding further light on anal fistulae and FiLaC compared with other procedures.

Unfortunately, there are only few papers published in the literature on the laser ablation of fistulas; most of them retrospective. Most series are based on limited sample sizes. In addition, the variability in both the type of fistulas treated and some technical aspects of the procedure failed to yield homogeneous data for analysis, so far.

GZ: Do you think Parks classification has an impact on the surgeon’s decision for using FiLaC?

PG: As for most-sphincter saving procedures, FiLaC is mainly indicated in ‘high’ fistulas. However, all cases where more invasive procedures are contraindicated due to potential impairment of continence could be treated with FiLaC.

Therefore, also selected patients with inter-sphincteric or low transphincteric fistulas showing ‘weak’ sphincters at preoperative evaluation could be good candidate to the FiLaC procedure

GZ: What do you think about the need of closing the internal orifice at the completion of the laser procedure?

PG: This is a controversial issue. The laser energy has the power of shrinking the internal orifice. Therefore, I believe an advancement flap or a direct suture of the internal orifice are not mandatory in the FiLaC procedure. However, this statement is not cast in the stone. When the internal orifice is big, largely exceeding the diameter of the fibre, a suture of the orifice could be a viable option.

GZ: Do you usually suggest performing an MRI before using FiLaC, and why?

PG: Preoperative evaluation usually includes MRI and/or endorectal ultrasound in my experience. This helps in the diagnosis of complex, recurring, multi-tract fistulas.

GZ: Do you think FiLaC is a good choice for smoking or obese patients or for a person suffering from comorbidities such as diabetes mellitus?

PG: All the papers published in the literature on FiLaC failed to show significant comorbidity factors affecting the success rate of this procedure. In addition, since FiLaC is a minimally-invasive treatment with low impact on continence, I would recommend this procedure also for frail patients with serious comorbidities.

GZ: What can you tell us about the role of seton treatment in FiLaC?

PG: In my series, patients with a draining seton or a silicon loop placed at a ‘first stage’ procedure, showed statistically significant higher healing rates than those without. I believe the presence of a loop or a seton within the tract, makes the caliber of the fistulas more homogeneous, reduces the diameter and increases the fibrotic tissue around fistulas, making them more suitable to laser treatment.

GZ: What is the role of FiLaC for patients with Crohn’s disease?

PG: The low impact on anal continence and the low morbidity rate can certainly encourage its use in patients with Crohn’s disease. Unfortunately, only a couple of papers in the literature reported results on this kind of patients and, of course, a lot of variables need to be considered in this kind of patients.

GZ: Why is FiLaC an important treatment in colorectal surgeons' armamentarium?

PG: Because it gives us a chance of treating patients with a reasonable percentage of cure, low post-operative discomfort and, in general, low associated morbidity.

We need to take in account patients’ fear for incontinence. Especially, but not only, patients with recurrent fistulas are desperately seeking for minimally-invasive treatments that can not possibly impair their continence. As surgeons we need to consider their fears and requests. FiLaC could be a good answer to their expectations.

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