Suture
materials
The different types and ideal properties of sutures at described in
Tables 49.5 and 49.6.
A suture can be chosen with different
properties in mind a follows.
Absorbable
Catgut is the oldest suture material known and is made from the
submucosa of sheep intestines. It can be chromic or plain and is still the most
frequently used suture material for intestinal anastomoses.
Delayed or
nonabsorbable
Very few sutures are truly completely
nonabsorbable. Silk is derived from the cocoon of the silkworm larva. The suture
is braided round a core and coated with wax to reduce capillary action. Tissue
reaction is greater than to the synthetic nonabsorbables because silk is a
foreign protein. For this reason silk is not now used in anastomoses, and most
surgeons prefer to use a monofilament synthetic suture if a nonabsorbable suture
is deemed necessary. Wire sutures are ideal for qualities of inertness and
permanence but working with them is difficult and they are virtually absolete.
Staples
Circular, linear and linear-cutting stapling
devices are used to form anastomoses. The devices carrying these staples can be
disposable or reusable. Until 1986 the staples were always nonabsorbable, being
made of stainless steel. However, absorbable staples have now been developed.
The circular stapling device is used for oesophageal and rectal anastomoses.
Their use is not a short cut to the joining of two pieces of intestine. The
preparation of the bowel ends and the placement of the purse-string sutures must
be carefully executed. They do, however, help in situations where the placement
of sutures can be difficult, e.g. a low colorectal or anal anastomosis in a
patient with a narrow pelvis (Fig. 49.6).
Linear
stapling for anastomoses may leave awkward edges and ends (Fig.
49.6).
Linear-cutting staplers can save time if very long closures or multiple
anastomoses are necessary but have little benefit over hand-sutured anastomoses.
It
is necessary to choose suture material that has the best characteristics for
carrying out an anastomosis in a particular site. Vascular anastomoses require
fine suture materials with minimal tissue reaction — strength is a secondary
consideration — and Prolene is commonly used. Gut anastomoses require
sutures with good handling qualities with secure knotting; pliancy is also
important, as is strength when the intestine begins to contract. Plain catgut is
unsuitable for intestinal anastomoses, but chromic catgut can be used for
gastric and small intestinal unions. Rectal and oesophageal anastomoses should
employ unabsorbable, or long-delayed absorbable sutures (e.g. PDS), because
these areas combine many adverse factors with the requirement to withstand
powerful contractile activity.