EComment. The cheaper and efficient methods of prevention of deep sternal wound infection

Abstract

I read with interest the work of Shaikhrezai and colleagues, in which they elaborated on the influence of the number of sternotomy mechanical fixation points on deep sternal wound infection (DSWI) and stated that the reasons for adopting the method was its non-association with increased cut-through in the sternum, sinuses or sternal wound infection. Furthermore, they showed that the risk of DSWI was significantly increased in patients in whom 8 or fewer paired points of sternal wire fixation were used compared to patients in whom 9 or more paired points of fixation were used (P= 0.002) [1]. The prevention of DSWI focuses mainly on achieving mechanical sternal stability and preventing infection; and biomechanical failure is usually due to sternal wire cut-through.[2] So, using more sternal wires will similarly entail more assaults on the sternum, and more when used singly as the force will be more concentrated on the horizontal axis as opposed to using the figure-of-eight type of sternal wiring where the force is distributed along both the horizontal and diagonal axes. For a given force, an increased area occasioned by the use of figure-of-eight type sternal wiring will make the cut-through pressure on the sternum lesser as compare to the use of the single sternal wiring technique; for pressure is force per area. Again, they stated that the incidence of wound sinuses was not associated with the number of wires [46 (4.9%) vs 157 (5.8%), P = 0.16][1]. This statement is also difficult to accept. Logically, the number of wires, especially when the tip is not properly buried into the sternum could irritate the skin and give rise to sinus formation with possible infection. If the number of such wires with the tip pointing out increases, the number of sinuses formed will increase accordingly and vice versa. Thus, the number of wound sinus formation is directly proportional to the number of sternal wires used. The methods of achieving biomechanical sternal stability and prevention of DSWI go beyond the mere application of sternal wires alone. Cheaper and efficient surgical manoeuvres that could also be applied are: the use of an interlocking sternotomy which is a safe, simple and reproducible lazy-S-shaped incision that provides efficient interlocking of the sternum and significantly reduces the incidence of sternal instability and prevents sternal dehiscence and mediastinitis, especially in diabetics [3]. The second method is sternal strapping, which in addition to helping to achieve haemostasis and avoid the use of bone wax, also offers mechanical protection, acting as a shield against bacterial contamination with beneficial effects on sternal healing [4], and prevents direct repeated trauma to the sternal edges during the application of spreader. Lastly, the adoption of surgical techniques such as the proper use of diathermy, judicious use of antibiotics, proper application of sternal wires and adopting good aseptic techniques will lead to the maintenance of low incidence of sternal wound infection [5]. In conclusion, DSWI can be reduced to a low level or prevented by adopting simpler, cheaper and efficient techniques as enumerated. Conflict of Interest: None declared