Primary closure of clean surgical wounds

Healing by primary intention or closure is the sequential closure of the wound after the completion of surgery. It is described as one of the simplest forms of wound repair (Kumar et al. 1997). In most cases, these wounds heal quickly and without complication. These wounds benefit from carefully handled tissue, negligible dead space and minimal tissue loss. Using the smallest size of suitable suture, wound margins are skilfully aligned with exacting tension in environments heavily influenced by infection prevention concerns. Primary closure wounds from clean surgery (PCCS), where infected/inflamed tissue and perioperative contamination are not encountered, have a surgical site infection (SSI) risk of between 1%-5% (Health Protection Agency [HPA] 2011).

Wound healing

Following surgery, healing takes place during the three broad processes of respond, repair and refine (see Fig. 1). The respond stage refers to the processes the body undertakes to rebalance itself (return to homeostasis). Following the creation of the wound, the sympathetic nervous system, wound hormones and inflammatory processes are stimulated (Walsh 2004). Chemical mediators or communicators trigger the microvascular and the cellular pathways. The microvascular events brought on by injury (including vasodilation and increased vessel permeability) aim to stop the bleeding and protect the area from bacteria ingress, as well as facilitate the cellular pathway. The cellular pathway is a series of processes undertaken by specialised cells which may either engulf or take up and destroy bacteria (phagocytosis) or debris (Woolf 2000). During the repair stage the integrity and function of the epithelial surface is reestablished. Within 24 hours, the narrow incision line is covered by new epithelial cells (which are initially vulnerable to shear forces) and fibroblast cells initiate processes for the epidermal layer to form a tight pattern that will be resistant to penetration (Ather and Harding 2007, Mercandetti and Cohen 2005). Fibroblasts also assist in restoring tissue below, as the many different types of collagen and extracellular substances provide a framework for new tissue and endothelial cells form new blood vessels (angiogenesis). PCCS may be distinguished from wound healing by secondary intention by the apparent expediency of this phase, and by the comparative measures of wound contraction and granulation. During the refine stage, the many migrational activities previously orchestrated in the early stages are no longer required, and the wound matrix is improved, strengthened and remodelled over time (Boughton 2006).