Suture materials are now routinely swaged to an atraumatic needle, and the characteristics which separate one from another concern whether the material is non-absorbable and needs to be removed, or absorbable and can be left in situ, the extent to which it causes tissue reaction, and how it handles in clinical practice. In its handling characteristics, silk remains the bench mark against which other non-absorbable suture materials are measured, but for many sur-geons synthetic materials such as nylon and pro-lene have largely replaced it, because the tissue reaction to their presence is less marked.
Their handling characteristics have also improved, though they still do not match those of silk. Using silk, the appropriate degree of eversion of the wound, the correct tension in tying the suture, and the placing of the knot to ensure that the wound edges are accurately apposed, are all easier to achieve than with the synthetics. Local reaction to the silk may be greater, but it lasts only until the suture is removed, when it imme-diately subsides.
The multifilament silk is easier to remove atraumatically than the more rigid monofilament synthetic. In short, the technical aspects of suture insertion and removal are easier with silk than synthetics. The extent to which these virtues might legitimately be considered to offset the temporary adverse tissue reaction which it causes is debatable.
There is no objective evidence to suggest that the results achieved with the synthetics are any better than those achieved with silk, but there is also no doubt that to use silk is currently viewed as old fashioned. The absorbable materials produce a much more severe tissue reaction, and one which con-tinues until they are completely resorbed. The reaction to buried catgut is generally considered to be greater than with the newer synthetic mater-ials, such as Vicryl, Dexon and PDS.
This gener-alisation needs to be analysed in a little more depth, since the amount of the reaction also depends on the volume of the buried material. Even the slower absorption of the newer materials is accompanied by the presence of a granuloma at the site of each buried suture, even on occasion an abscess, and these persist as long as the material remains.
There is an increasing trend towards the use of inverted absorbable sutures to hold the edges of the dermis together, used with the aim of taking up any tension in the wound, and used along with or without cutaneous non-absorbable or a continuous subcuticular suture. The rationale is that the incidence and severity of cross-hatching is reduced, and that the persistence of the buried sutures will allow formation of the scar to pro-ceed with minimal tension, reducing the degree to which the scar will stretch. Here again, the evid-ence for this is derived from clinical impression.