Advice

The technology

The technology

VAAFT is a surgical kit for treating anal fistulae. The system comprises:

  • A video telescope (fistuloscope) to allow surgeons to see inside the fistula tract.

  • A unipolar electrode for diathermy of the internal tract. This is connected to a high frequency generator.

  • A fistula brush and forceps for cleaning the tract and clearing any granulation tissue.

The VAAFT procedure is done in 2 phases, diagnostic and operative. Before the procedure, the patient is given a spinal or general anaesthetic and is placed in the lithotomy position (legs in stirrups with the perineum at the edge of the table).

In the diagnostic phase, the fistuloscope is inserted into the fistula to locate the internal opening in the anus and to identify any secondary tracts or abscess cavities. The anal canal is held open using a speculum and irrigation solution is used to give a clear view of the fistula tract. Light from the fistuloscope can be seen from inside the anal canal at the location of the internal opening of the fistula, which helps to locate the internal opening.

In the operative phase of the procedure, the fistula tract is cleaned and the internal opening of the fistula is sealed. To do this, the surgeon uses the unipolar electrode, under video guidance, to cauterise material in the fistula tract. Necrotic material is removed at the same time using the fistula brush and forceps, as well as by continuous irrigation. The surgeon then closes the internal opening from inside the anal canal using stitches and staples.

VAAFT can also be used for treating pilonidal sinus but this is beyond the scope of this briefing.

Innovations

VAAFT is claimed to be the only technique that allows the surgeon to see inside the anal fistula tract and locate the internal opening using an endoscope light. VAAFT is designed to only affect the fistula tract, preserving sphincter muscle function and faecal continence.

Current NHS pathway

Surgery is usually necessary to treat anal fistulae because they rarely heal spontaneously. Several techniques are currently used within the NHS; which one is used depends on the location 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).

Fistulotomy is the most common type of anal fistula surgery, used in 85% to 95% of cases (Seow-Choen 2003). 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 (ligation of inter sphincteric fistula tract) and mucosal advancement flap 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 the closure of anal fistula using a suturable bioprosthetic plug, made from porcine or human tissue. The guidance states that evidence of the efficacy for these is limited, and recommends that they should only be used with special arrangements for clinical governance, consent and audit or research.

Fibrin glue can be injected into the fistula tract in an attempt to seal it. Evidence for this procedure reports initial success rates of 50%, but long-term findings indicate that it may be associated with a high rate of recurrence (Cirocchi et al. 2009).

NICE is unaware of any CE-marked technologies which fulfil a similar function to VAAFT.

Population, setting and intended user

VAAFT is an option for adults and children with anal fistulae in place of current standard surgical approaches. It is used in secondary settings as a day-case procedure and is done by a surgeon trained in the VAAFT technique.

Costs

Table 1: Device costs

Description

Cost

Additional information

Indicative price of technology

£7,988 for reusable VAAFT equipment set (excluding VAT)

–

Consumables

£5.70 per single-use seal

£15.00 per single-use fistula brush

Irrigation fluid

–

Service/maintenance cost and frequency

Ad hoc repairs when necessary

£158 to £3,337

The manufacturer estimates this would amount to around £7,000 over the lifetime of the device

Lifespan is 10 years

One kit can be used once per day (rest of day needed for sterilisation)

Training provided at no charge to surgeons

Average cost per treatment

£26.40 (equipment costs)

£1,195.40 total

Day-case procedure done under general anaesthetic £1,169 2014–15 national schedules (day-case FZ21C)

Costs of standard care

Fistulotomy is the most common treatment for anal fistula. It is usually done as a day-case procedure under general anaesthesia, costing £1,169. Additional costs are incurred if a draining seton is used before surgery.

Resource consequences

There could be a reduction in secondary care costs if VAAFT reduced or avoided the need for MRI scans. An MRI scan costs between £120 and £180 per person (enhanced tariff 2015/16). There may also be further potential savings from a reduction in the use of post-operative wound dressings (because after VAAFT wounds are not left open, unlike after fistulotomy) or from reduced fistula recurrence, although data to quantify these potential savings are not currently available.

VAAFT is currently used in 4 NHS hospitals in the UK.

Training is needed in the use of VAAFT but the manufacturer includes this in the purchase price. Adopting VAAFT may change the way services are delivered, because it can be done as a day-case procedure.