I've found the following, it is likely it may be of some help

http://www.google.com/patents/EP1876965A2?cl=en

Further, in certain embodiments, the mold can be configured to form a spool or dumb-bell type structure 24 at the proximal end of the graft construct 20. Illustratively, the spooled section 24 can be used to assist with placement of the graft 20 within a fistula tract, such as for example, by winding or otherwise attaching or locating a string or suture within the spool 24 and thereafter using the suture to pull the graft 20 proximally through the tract, as is discussed in further detail below.

http://www.bowel-health.com/fistula.html
The principle of seton is that no fistula will close permanently if the “feeding” abscess or infection does not drain completely. After a partial excision of a fistula the external (skin) orifice has a tendency to close much faster than the internal orifice. The internal orifice is inside either an abscess cavity or
the anus/rectum (which contains faeces and plenty of bacteria). Thus, early closure of the external fistula orifice will “trap” infection inside the fistula track and will result in a recurrent abscess/ infection. By keeping the fistula track patent
and draining for a long time we allow the gradual complete drainage and clearing of the infection.

Treatment
As for virtually any abscess, the primary treatment is prompt incision and drainage of the abscess.
http://www.crohnsforum.com/wiki/Seton
Typically made from a large silk suture, silastic cord, or surgical rubber band, a seton is used to help heal fistulas by allowing a fistula tract to drain, while helping to avoid septic and potentially painful collections of pus or infection.[1]

A colorectal surgeon places a seton by running it through a fistula and creating a loop that joins outside the fistula. A seton allows the fistula to drain without allowing the wound to “heal over.” The two ends of seton are tied together, clasped, or clamped to complete the loop and to avoid having the seton being prematurely removed.[2]
http://en.wikipedia.org/wiki/Seton_stitch
A seton or seton stitch is, in medicine, a procedure used to aid the healing of fistulae (abnormal connections between two epithelium-lined organs or vessels).
The procedure involves running a surgical-grade cord through the fistula tract so that the cord creates a loop that joins up outside the fistula. The cord provides a path which allows the fistula to drain continuously while it is healing, rather than allowing the exterior of the wound to close over. Keeping the fistula tract open can help keep from trapping pus or other infectious material in the wound.
Setons can be tied tightly or loosely and with different materials, depending on the anatomical location of the fistulae and what may be medically required. A seton might be tied loosely as a palliative measure to avoid septic and painful exacerbations, or as temporary measure before surgical excision as in fistulotomy or fistulectomy. In some types of fistulae, a seton may be tied with more tension and tightened periodically. In this case, the seton loop will slowly cut through tissue inside the loop while scarring behind the loop, essentially "pulling out" the fistula without surgery.

http://fitsweb.uchc.edu/student/selectives/Luzietti/Painful_...
A seton is typically made from a large silk suture, silastic vessel marker, or rubber band, that is threaded through the fistula tract and serves three purposes. It allows direct visualization of the tract, it allows drainage and promotes fibrosis, and it also cuts through the fistula. That is, with time, as fibrosis occurs above the seton, it gradually cuts through the sphincter muscle, and exteriorizes the tract. The seton is tightened during repeat office visits until it is pulled through over 6-8 weeks. The advantage of using a seton, is that this "staged fistulotomy" allows for progressive division of the sphincter muscle, avoiding the complication of incontinence.


--------------------------------------------------
Note added at 1 giorno21 ore (2012-12-08 13:15:39 GMT)
--------------------------------------------------


@Daniel

Hi, 'mamma mia, mah..mah here I go again ... how can I resist you ...'
nice song for a wonderful movie!!! Do you remember it?
This is just for a change of mood from your text context. Happy translating.

--------------------------------------------------
Note added at 6 giorni (2012-12-13 08:35:01 GMT) Post-grading
--------------------------------------------------



Thank you indeed Daniel.

--------------------------------------------------
Note added at 6 giorni (2012-12-13 08:35:20 GMT) Post-grading
--------------------------------------------------



Thank you indeed Daniel.