Complications in Equine Surgery. Группа авторов

of nonviable tissue

       Inappropriate support and immobilization of a suture line

       Pathogenesis

       Infection

      All sutures produce a local tissue reaction to some degree, which increases the susceptibility to development of an incisional infection [4]. Infection can be the primary reason causing dehiscence or can be a sequelae to dehiscence [5]. Bacteria release proteolytic enzymes that inhibit wound healing, therefore inducing wound disruption and dehiscence [5].

       Tissue integrity and perfusion, local wound repair responses, and bacterial challenge, influence the presence of an infection of the suture line [6].

       Degree of bacterial contamination is a useful predictor of incisional/wound infection potential [7].

       Improper wound cleansing with cytotoxic substances or overzealous scrubbing can result in unnecessary tissue inflammation, edema, and necrosis, all leading to an increased risk of incisional infection and dehiscence [8].

       Inadequate or traumatic debridement of necrotic, devitalized, heavily contaminated tissue and organic debris increases risk of incisional infection and dehiscence.

       Use of a larger suture size than necessary results in unnecessary foreign material present within the wound/incision, altering the tissue structure, weakening the repair, and therefore decreasing the capacity to resist infection [3, 9]. Physical and biochemical characteristics of the suture serve as an important factor in the initiation, severity, and persistence of incisional infections [4]. Bacteria have a higher affinity for braided suture compared to monofilament suture [4]. Removal of bacteria by the body’s defense mechanism is slower with braided suture [4]. The use of barbed sutures has been shown to increase the risk of incisional infections [10],

       Suture pattern choice can contribute to prolonged edema and erythema from decrease in microvascular flow, resulting in delayed healing, decreased incisional tensile strength, and risk of incisional complications [11].

       Suture placement

      Sutures that are placed too close to the wound margins risk suture cut‐through due to an initial elevated collagenase activity within 5 mm of the wound edges, leading to an increased risk of suture cut‐through and dehiscence of the wound [5].

       Poor knotting technique

      A poor knot‐tying technique can result in the knot untying and wound dehiscence [5].

       Inappropriate suture material

      Selection of an inappropriate suture material with insufficient tensile strength for the given tissues or that significantly decreases in tensile strength (resorption time) faster than tissue healing occurs for the respective tissue, increases the risk of dehiscence [5]. Interactions between the suture material and tissue can alter the characteristics of the suture and lead to suture failure [9]. Barbed sutures have been shown to increase the incidence of postoperative incisional dehiscence and erythema as wound complications [12].

       Premature suture removal

      Suture removal prior to appropriate wound healing may result in dehiscence [5].

       Improper suture needle selection

      The type of needle and size in relation to the suture can increase the risk of suture cut‐through, especially when there is tension present or tissues are compromised [5].

       Inadequate suture line tension

      Loosely placed sutures due to inadequate surgical technique or as a result of anticipated edema formation, as well as a suture line placed in a region of already present edema, increases the risk of wound edge retraction and incisional gapping when the edema resolves [5].

       Excessive suture line tension

      The use of excessive suture tension or use of an inappropriate suture pattern for mild to moderate tension along a suture line to appose tissues can result in suture cut‐through leading to dehiscence. Excessive suture tension can affect the local blood flow, which increases the inflammatory response resulting in tissue ischemia and pressure necrosis [3, 6, 7]. The use of suture stents or quills in an attempt to diffuse the tension from the suture to a larger surface area can also affect microvascular supply and result in tissue pressure necrosis under the stent or quill, especially when placed under a pressure bandage or cast [3].

       Dead space

      Dead space is created in some traumatic wounds where tissues have been lost or dissection planes have been created. Dead space is created surgically after tissue debridement, mass removal, or undermining has been performed to relieve tension for the closure. As a result, seroma or hematoma formation may manifest, increasing the risk of incisional infection and possible dehiscence [4].

       Suturing of nonviable tissue

      The degree of tissue compromise and viability of recently traumatized tissues can be difficult to predict. If a traumatic wound is closed too promptly, without allowing or anticipating the potential ensuing development of tissue necrosis to occur, the development of delayed necrosis may lead to dehiscence [5].

       Inappropriate support and immobilization of a suture line

      Excessive motion for any given suture line increases the risk of tension on the wound edges and possible dehiscence [5]. The repetitive motion of an incision causes chronic inflammation from microvascular, collagen deposits, and epithelialization disruption [7]. However, complete immobilization can result in disorganized new collagen and decreases incisional tensile strength [7]. Inadequate support and/or immobilization of a suture line as well as inadequate confinement can have detrimental effects on the wound/incision healing process and result in dehiscence.

       Prevention

      Effective apposition of the wound/incision edges, atraumatic tissue handling, minimal disruption to blood supply, appropriate suture pattern, material, needle, and placement are essential requirements for a positive healing outcome [3, 5]. Adequate perioperative care is also an important factor in incisional healing and appropriate use of antibiotics, NSAIDs, diagnostics, bandaging, and confinement are important. Appropriate bandaging and NSAID uses can prevent excessive edema formation. It is important to inflict the least amount of trauma achievable to obtain the goal of the surgery [9].

      The wound strength is more dependent on the tissue’s ability to hold the suture than on the given suture strength [2]. Suture placement from the wound edge is recommended an equal distance from the incision/wound edge as the thickness of the skin edge at that location [3]. Due to the normal inflammatory phase of healing, sutures should be placed at least 5 mm from the wound/incision edge to prevent dehiscence [3]. Spacing between sutures is variable, depending on wound/incision location and relative local tension but it is advised to use the minimum number of sutures necessary to achieve tissue apposition [3]. In general, this corresponds to fewer sutures in thicker skin and areas of low tension and more sutures in regions of thin skin and higher tension [3]. Suture pattern choice can contribute to prolonged edema and erythema, such as with a simple continuous suture pattern when compared to a simple interrupted suture pattern [11]. This edema can result in delayed healing and risk of complications [11].

      Physical and biological characteristics should be considered when selecting