Advice
The technology
The technology
Permacol collagen paste (Medtronic) is a minimally invasive treatment for anal fistulae. The paste is made of acellular, porcine dermal collagen suspended in saline. When injected into the fistula tract, the paste expands to fill the internal shape of the fistula, enabling closure of the channel. Permacol may be used as a single treatment option or in conjunction with another treatment such as the LIFT (ligation of intersphincteric fistula tract) technique.
Permacol is supplied in a sterile 3‑ml syringe, and comes with a sterile guiding catheter. It is used under general anaesthetic with the patient in the lithotomy position (legs in stirrups with the perineum at the edge of the table). The fistula tract is de-epithelised and granulation tissue is removed, before being cleaned with dilute hydrogen peroxide followed by saline. The guiding catheter is connected to the Permacol syringe and the other end is inserted into the external opening of the fistula. The paste is injected into the fistula until it is visible at the internal opening, and then the guiding catheter is slowly withdrawn.
The internal opening of the fistula is closed using resorbable stitches. The external opening is partially closed, using resorbable stitches if needed, to allow any inflammatory fluid to drain out without allowing the Permacol paste to escape.
Innovations
The potential innovation is that Permacol fills the exact shape of the tract. This is intended to reduce the risk of it being expelled from the body when defaecating, which can happen with collagen plugs.
Current NHS pathway or current care pathway
Surgery is usually necessary to treat anal fistulae as they rarely heal by themselves. Several surgical techniques are currently used within the NHS. The choice of technique depends on the position of the fistula and the person's medical history. MRI scans are usually done before surgery to assess the extent and location of complex or transphincteric fistula tracts, and recurrent fistulae. The aim of surgery is to drain infected material so that the fistula can heal, while ensuring that the function of the anal sphincter is preserved. If the fistula does not heal properly it may reoccur and need another surgical procedure (Dudukgian et al. 2011). The procedure is done by a colorectal surgeon.
Fistulotomy is the most common type of anal fistula surgery. This involves cutting open the whole length of the fistula, from the internal opening to the external opening, before the surgeon cleans out the contents and flattens it out. This leaves an open wound which must be cleaned and dressed while healing; after 1 to 2 months, the fistula will heal into a flat scar. This surgery is usually done as a day-case procedure under general anaesthesia. Depending on the position of the fistula, a fistulotomy may involve cutting the anal sphincter which can lead to faecal incontinence.
Seton placement is often used if the person is considered to be at high risk of developing faecal incontinence. This technique involves threading a stitch (the seton) through the fistula tract and back out through the anus where it is loosely tied. The anal sphincter is not cut. Two types of seton may be used: a silicone draining seton, or a silk or polyester cutting seton. A draining seton allows a fistula tract to drain for several weeks or months before a surgical procedure. A cutting seton is a non-absorbable stitch placed in the fistula tract and tightened periodically, to slowly cut through the fistula. Several seton procedures or a combination of seton and other techniques may be needed to treat a single fistula. Seton placement is done under general anaesthesia.
LIFT and mucosal advancement flaps are alternative procedures that also avoid cutting the sphincter muscle. LIFT involves opening the space between the muscles to access the fistula tract, whereas a mucosal advancement flap involves closing the internal opening of the fistula with a flap of tissue and cleaning out the fistula tract.
NICE has produced interventional procedures guidance on closure of anal fistula using a suturable bioprosthetic plug, made from porcine or human tissue. The guidance states that the evidence of the efficacy of these is limited, and recommends that they should only be used with special arrangements for clinical governance, consent and audit or research. NICE also recommends that, where patients are treated outside a clinical trial, clinical outcomes are audited and reviewed.
NICE has also produced a medtech innovation briefing on VAAFT (video-assisted anal fistula treatment), a surgical kit for treating anal fistulae.
Population, setting and intended user
Permacol is intended as an option for adults and children with anal fistulae in place of current standard surgical approaches. In people with multi-channel fistulae, Permacol could be used to treat smaller channels alongside more invasive surgical approaches being used for the main fistula. It is used by a colorectal surgeon in a secondary care setting, and is done as a day-case procedure under general anaesthesia.
Costs
Resource consequences
Permacol costs more than standard care, but this could be offset if it led to a reduction in post-operative wound care, recurrence or faecal incontinence. The management of faecal incontinence is estimated to cost up to £2,635 per person per year. Minimal training will be needed for theatre staff and surgeons.