Even in skin abrasions, a significant rise in bacterial swab colony forming units is to be expected within 24 h following trauma [23]. Thus, in the poly-traumatized patient with fractures, an initial microbial swab evaluation is useful for the anticipation of (1) infections caused by environmental pathogens. These include Bacillus, Clostridium, Corynebacter, Pseudomonas or Actinobacter species, (2) fungal infections, e.g. Aspergillus species, (3) early onset bacterial infections, e.g. Streptococcus and Staphylococcus species or (4) pre-existing multi-drug resistant bacteria strain carriers, e.g. methicillin-resistant staphylococcus (MRSA). A switch from initially present body surface colonization or environmental wound contamination to nosocomial, hospital acquired bacterial strains (e.g. Staphylococcus, Escherichia coli, Proteus, Enterococcus, Bacteroides species) can be typically expected within 72 h post trauma, again advocating early definite surgical closure of wounds. However, to the authors’ knowledge, related to a risk assessment for possible wound infection, no evidence-based data exists which dictates delayed vs. primary wound closure [24]. Overall, staphylococcus species remain the most common cause of surgical wound infections [25].

Live threatening infections related to initial wound contamination are typically characterized by a sudden onset and rapid progression of soft tissue inflammation and necrosis. Thus, surgical decision making often is solely based on clinical presentation alone. They include: (1) Gas gangrene [26] (e.g. Clostridium perfringens), more defined by tissue-lytic toxin effects (e.g. alpha toxin) rather than bacterial load, can be anticipated in patients with an initial wound contamination with soil as well as with a diabetic, alcoholic and peripheral artery disease (PAD) predisposition. Here, the avoidance of ischemic wound conditions is paramount. A fulminant course of tissue necrosis, intra-tissue gas formation and emergency gram-staining should motivate early and extensive surgical debridement or amputation along with a supportive therapy, e.g. hyperbaric oxygen therapy and antibiotics. With manifestation in the genital region, usually a mixed infection with aerobic and anaerobic bacteria is present, termed Fournier’s gangrene (1883). (2) Necrotizing fasciitis [27] (e.g. Streptococcus pyogenes, Staphylococcus aureus, Clostridium perfringens, Bacteroides fragilis, Aeromonas hydrophilia) shares features with gas gangrene in that toxin effects will cause a sudden, fulminant progression of disease on a subcutaneous, epifascial plane but initial soft tissue reaction is often bland with only minor swelling or redness that does not correlate well with severe pain in the conscious patient. Early surgical intervention is mandatory with diagnosis usually confirmed by tissue histology. (3) Tetanus [28] (Clostridium tetani), due to extensive passive anti-toxin vaccination programmes is a rare condition in developed countries. However, because of its potential lethal cause; checking up-to-date vaccination remains a mandatory part of any initial wound management. (4) Botulism [29] (Clostridium botulinum), a lethal, toxin-defined disease is avoided by sufficient initial wound de-contamination and mitigated by early diagnosis with passive vaccination. (5) Erysipelas [30] (Streptococcus pyogenes) caused by a superficial, non-pyogenic infection of upper layers of the skin by streptolysin O/S exotoxin expressing strains can be readily treated following early diagnosis using antibiotics combined with antiseptic dressing regimes. A more severe, ‘bullous’ from that often requires secondary defect coverage can be distinguished based on the appearance of large areas of toxic epidermolysis [31].

Radical surgical debridement of contaminated or critically damaged, non-viable tissue represents a widely accepted, mandatory part of any surgical first intent strategy. Following initial stabilization of vital body functions, both through intensive care management and surgical control of haemorrhage or acute brain damage, a close multidisciplinary approach is required.

Acute phase surgical measures comprise (1) the avoidance of prolonged ischaemia by securing sufficient arterial perfusion and venous return through re-anastomosis, evacuation of hematoma or decompression of muscular compartments; (2) decontamination of wounds using techniques such as excision of wound edges according to Friedrich (1889) [32], bursectomy, jet-lavage [33], versa-jet [34], open aseptic wound management [34] or the application of occlusive, vacuum-based dressings [35]; (3) additional measures to ensure a viable environment for the primary or secondary reconstruction of nerves, tendons or ligaments.

Soft tissue injury to the upper and lower extremities has been shown to be most susceptible to early infectious complications opposed to soft tissue injuries of the head, neck and genital region [36]. In general, primary wound closure should be attempted within 6 h following trauma which also coincides with an expected peak in tissue swelling.

Comparable to an initial surgical debridement of traumatized soft tissue, a surgically motivated ‘second look’ strategy should occur.Given the post-traumatic inflammatory response [37–41], debridement and revision early after trauma has proven highly effective in improving overall patient outcome [42].

In general, if primary wound closure is not feasible, defect coverage can be achieved by two major principles.

First, by allowing the formation of granulation tissue which will lead to stable and well perfused wound(beds) which in turn can then be closed using various techniques of autologous skin grafting. This approach is usually limited to soft tissue defects that will not leave bone or tendons exposed. However, in recent years, development and application techniques regarding the use of biodegradable skin substitutes [45] such as MatriDerm® [46] or Integra® [47] have matured sufficiently to allow for coverage of exposed bone, muscle or tendons with stable and functionally satisfying results (Fig. 7.3).

Secondly, any type of surgical measure that will ‘move’ a defined block of tissue from one area to another defines defect coverage using flaps. A block of tissue that does not incorporate a defined vascular pattern is called a ‘random pattern’ flap, as opposed to the ‘axial pattern’ or ‘island’ flaps with an identifiable vascular pedicle. Flaps with a vascular pedicle are most versatile since they allow for a safe mobilization of large tissue blocks both locally and distally as ‘free flaps’. A list of flaps commonly used for defect coverage is given in Table 7.1. The authors’ recommendation for defect coverage using flaps in defined anatomical areas is given in Fig. 7.4.

Random pattern flaps are essentially synonymous with locally mobilized skin flaps. Standard skin flaps used for defect closure are further sub-categorized based on the underlying principle of mobilization as either advancement, transpositional or rotational. A key consideration of local tissue mobilization for defect closure is that unidirectional loss of tissue mobility (through defect) is best compensated for by tissue mobilization along a main vector that is perpendicular to a corresponding vector of reduced tissue mobility. Also, as a rule of thumb, the ratio between length and width of a randomly patterned flap should not exceed 3:1 for sufficient flap perfusion. This ratio can be modulated using, e.g. a ‘bridge’ flap technique, effectively creating two pedicles.

A detailed study of human vascular anatomy underlying skin perfusion such as performed by C. Manchot (1889) and M. Salmon (1936) proved to be essential for the design of larger skin or fascio-cutaneous flaps. Human vascular anatomy (opposed to, e.g. rodent models) rarely allow larger cutaneous flaps to be raised based on a vascular pedicle that runs along the subcutaneous plane. Instead, skin perfusion is predominantly ensured by ‘perforators’ which originate from a deeper muscle plane. Thus, the vascular anatomy of skin is closely linked to that of muscle. Regarding free transfer of muscle tissue, a highly valuable classification system of muscular artery perfusion was introduced by Mathes and Nahai [48]. Nowadays, so-called perforator flaps play a dominant role whenever coverage of soft tissue defects of significant size and depth is required. As already mentioned, perforator flaps are essentially fascio-cutaneous flaps where a substantial area of skin and underlying fat tissue are dependent on a vascular pedicle that usually perforates perpendicular to the surface plane of the flap. Design and surgical preparation of a perforator flap requires a concise knowledge of a perforator’s relation to the vascular system of an underlying muscle. As elaborated by Cormack and Lamberty [49], a perforator-based flap pedicle might require transmuscular, septal, subfascial preparation techniques. Knowledge of perforator anatomy is also invaluable in raising osteo-myo-cutaneous flaps. In order to minimize donor site co-morbidity due to flap raising, muscle flaps are usually reserved for large and deep defects requiring a certain volume and an increased ‘mechanical resistance’ of the flap. Also, commonly used muscle flaps do cause only minor functional deficits. A ‘monitor skin island’ as part of a muscular flap is still considered the most practical way of monitoring adequate flap perfusion despite various alternative approaches or monitor devices available on the market (e.g. O2C™ [50]).