Plugs, goops and threads for trans-sphincteric anal fistulae

Rick Nelson, Northern General Hospital, Sheffield

In recent literature over 35 treatment strategies have been published for the treatment of trans-sphinctertic anal fistula. Does that imply that none of them work? Or that we simply don’t know if they work. The latest technology in this regard is the porcine collagen fistula plug.
Below is a list of treatment strategies that have been tested in randomized clinical trials (except one):

Strategy Number of RCTs evaluating that method

With an apparent 33 RCTs published it would seem that an optimal treatment strategy could be derived from a systematic review of these data and analyses. Yet study quality and experimental designs in fact leave the most seminal questions relating to anal fistula unanswered. These are:

1. A classification system that reliably predicts how much sphincter can be laid open in fistulotomy without causing a continence disturbance.
2. Like anal fissure and internal sphincterotomy, what is the nature and optimal treatment strategy for patients who develop continence disturbance after fistula surgery?
3. Should a fistula found during drainage of a peri-anal abscess be treated at the time of abscess drainage?
4. Why are fibrin glue and porcine collagen plugs apparently extruded in the majority of patients?
5. Do flaps really preserve continence?
6. Do setons of any type preserve continence?
7. Does imfliximab really heal fistulas, or just dry them up for a time?
8. What is the gold standard therapy against which any new treatment should be measured against in future randomized trials of treatment efficacy?

Ref.s
Malik AI, Nelson RL. Surgical management of annals fistula: a systematic review. In press. Colorectal Disease

Holzheimer RG, Siebeck M. Treatment procedures for anal fistulous cryptoglandular abscess – how to get the best results. Eur. J Med. Res. 2006;11:501-15.