Primary healing by accurate apposition is considered the ideal
for epithelial wounds, and intestinal anastomoses should be no
different. However, most anastomotic techniques do not aspire
to accurate realignment and consequently depend on secondary
healing. Most intestinal anastomoses heal uneventfully because
of the relatively profuse blood supply of the bowel and the fact
that the process of healing is hidden within the abdomen.
Intestinal anastomoses heal in a series of overlapping phases:
• lag phase (days 0–4), in which the acute inflammatory
response clears the wound of debris
• phase of fibroplasia (days 3–14), in which fibroblasts
proliferate and immature collagen is laid down
• maturation phase (day 10 onwards), in which collagen remodels.
Intestinal anastomoses have little intrinsic resistance to
distension and longitudinal distraction is weak until collagen
deposition is established. Extrinsic support is required during
the lag phase to maintain tissue continuity. The surgeon’s role is
to provide support (usually by inserting sutures or staples), and
to ensure optimal conditions for subsequent healing. Although
anastomotic technique is the single most important determinant
of outcome, a number of other factors affect healing (Figure 1); if
these combine to make the risk of anastomotic failure high, the
wisdom of performing an anastomosis should be questioned.