The primary blast effect is related to the rapid pressure wave created during the detonation of an explosive [53]. The scene location and type of explosive used have a direct effect on the severity of injuries. Blast wave energy tends to decrease rapidly in space and dissipate [54]. However, when blast occurs in a closed or confined space, such in a bus or a room, the blast waves are reverberated from the walls instead of dissipating [54–56], thus inflicting more damage on human victims. In a series of suicide bombing in Israel occurring in buses during the years 1995–1996, a threefold increase in primary blast injuries was observed when compared to those of open-space explosions, exemplifying this phenomenon [56]. When the pressure wave created by detonation encounters certain air-fluid interfaces, unique tissue damage may occur. The most common and perhaps the most life-threatening injury involves the lung. Pressure differentials across the alveolar-capillary interface cause disruption, hemorrhage, pulmonary contusion, pneumothorax, hemothorax, pneumomediastinum, and subcutaneous emphysema [57].

The second most common type of primary blast injury is that to hollow viscera. The intestines, most usually the colon, are affected by the detonation wave. Mesenteric ischemia or infarct can cause delayed rupture of the large or the small intestine; these injuries are difficult to detect initially. Rupture, infarction, ischemia, and hemorrhage of solid organs such as the liver, spleen, and kidney are generally associated with very high blast forces or proximity of the patient to the blast center [58].

Tympanic membrane injury was extensively discussed in the literature discussing terror attacks. It is the most common non-lethal injury caused by relatively low-pressure blast waves. Traditionally, its presence was used to predict severe primary blast injuries (such as the lung or bowel), yet it is now referred to as questionable and unreliable [59], as will be further discussed in the triage section.

Traditionally, limb injury due to primary blast was considered a rarity. Hull and Cooper studied primary blast effects on the extremities resulting in traumatic amputations in Northern Ireland [60]. Only 9 out of 52 victims with traumatic amputations due to primary blast survived, demonstrating the high level of energy needed to avulse a limb. However, in the military setting, with the use of body armor becoming a common practice, devastating primary blast amputation has become increasingly common. These can include multiple and higher limb avulsions as well as pelvic and perineal injuries – areas not well protected by armor [4, 61].

Traditionally, the secondary blast effects comprise the core of the orthopedic injuries observed in warfare [62, 63] and also in civilian terror attacks such as the Middle Eastern experience [50, 64, 65]. Secondary blast effects are related to penetrating injuries caused by fragments ejected from the explosives and/or by foreign bodies impregnated within it. The extent of this effect depends on the subject’s distance from the detonation center, the shape and size of the fragments, and the number of foreign bodies implanted or created by the explosive. In contrast to most warfare injuries, the improvised explosives used by terrorists have multiple added fragments including screws, bolts, nails, and other objects that may increase the damage caused by penetrating injuries [66]. Open fractures, severe soft tissue injuries, and multi-organ penetrating injuries are the more common pattern seen in the severely injured victim [66, 67].

Tertiary blast injury refers to the blunt trauma component of the explosion. Flying or falling objects can cause additional traumatic elements to those described above. When structural collapse takes place, a high casualty and mortality event occurs [48]. Our experience in Israel did not demonstrate a significant proportion of additional blunt trauma, but reports from other parts of the world, such as those following the Oklahoma City explosion, state this as the primary mechanism of the injury, as well as the [68] cause of usually devastating results.

The quaternary blast effect is a recently added one, and includes the thermal and chemical damage caused by fire and noxious substances occurring at the vicinity of the explosion. Confined-space explosions significantly increase these types of injuries [56].

Perhaps the most significant difference between gunshots and the blast wounded, besides the individual injury pattern, is the “mass-casualty” effect caused by multiple military and civilian attacks. Instead of treating a single patient brought to the treating facility, the surgeon faces a scenario of mass casualty, and is required to simultaneously deal with multiple patients having multiple injuries. Hence, the initial effort should be to establish an orderly triage system, and to allocate medical team and hospital resources even before the first patient arrives to the hospital [69, 70].

In the military setting, front medical teams utilizing “damage control” strategies and performing only emergency surgeries have recently developed, especially in the global war against terrorism [28]. Further procedures are then performed in secondary and tertiary centers after further triage and usually prolonged transportation. However, this is not the case in the civilian setting, which is in the primary focus of this section.

At recent attacks – such in Jerusalem, Madrid, and London and recently the Boston Marathon – evacuation time to a definite care facility ranged between 18 min to 1–2 h [51, 71–73]. Some events, especially those on a large scale, described only a few severely injured patients in a majority of “walking wounded”. The Middle East experience, such as in Jerusalem, paradoxically demonstrated that smaller bombing scenes resulted in overall less causalities but with more critically ill patients (4–8 per event) arriving in very short notice to treating facilities [48].

Logistics of Emergency Department management have a major impact on triage. We recommend evacuation of non-critical non-terror-related patients temporarily to the hospital floors while the seriously ill patients can be treated in designated areas. The trauma bays are thus devoted solely to resuscitative efforts done on critically ill patients, while the rest of the ED serves as an admitting area to the rest of the patients. Each area is staffed with surgeon-in-charge and other members of the treating team (surgical and orthopedic residents, nurses, medical students, etc.). A surgeon-in-charge should be designated beforehand and should serve in critical junctions as suggested by Almogy et al. [71]: Triage at the initial admitting phase and in various treating cycles as well as diagnostics and directions towards the operating room or admitting floors are constantly done, until the general chaos is reduced. Every hospital should explore and identify the logistics mechanism required to provide the best and most efficient setting for disaster management under its capacity, should an actual disaster occur.

The next important principle in managing an event of this nature is to direct the flow of patients in an orderly fashion in a “one way” system. Potential bottlenecks, such as in the CT scanner, ICUs, and limited number of available operating rooms, should be identified and the patients should be directed to their proper destination only after the available resources of the hospital are mapped and identified [48]. Since as many as 50 % of causalities would require a surgical intervention – ICU stay or both [74] – hospital management should be prepared to allocate these facilities in a timely fashion.

Blast extremity injuries tend to be more varied and less predictable than gunshots [16, 75]. The energy of the penetrating foreign body is extremely variable and greatly depends on the distance from the detonation center [62]. The existence of an extremity fracture, therefore, indicates a high-energy mechanism and has proven many times to implicate a polytrauma situation [76]. This is in contrast to a gunshot patient who can present with an extremity injury as a sole manifestation [16, 77]. In fact, one of the studies performed at our center indicates that fractures caused by blast are highly associated with potentially lethal blast lung injuries [78]. Therefore, an “isolated” fracture caused by blast mechanism should alert the surgeon to aggressively seek and diagnose associated injuries. Although high-energy gunshots wounds may involve a higher rate of vascular injury, compartment syndrome, and higher grade open fractures [16], blast extremity injury can involve more multiple fracture sites than gunshots, as well as a higher ISS and more associated life threatening injuries [16, 79, 80]. In this context, the treatment plans and strategies of each patient should be meticulously defined. As many patients are expedited to the operating room, more orthopedic teams should be available to undertake emergent procedures.

Damage control orthopedic and soft tissue strategies should generally be the rule in these cases since 70 % of bone-injured blast patients have an ISS of above 20 [75, 77] and are highly prone to prolonged ICU stay, respiratory failure, and coagulopathy [52, 79]. An orthopedic surgeon-in-charge should direct the teams in decision making, and the scope of first stage treatment plans should be limited as reconstruction can be planned in subsequent phases.

As in blunt polytrauma situations, tertiary surveys are extremely important in order to identify missed injuries, most of them of musculoskeletal nature [81]. We established a routine of a “morning after” rounds using the records from the ED to allocate the patients in the entire hospital, performing vigilant physical examination and documenting the penetrating injury both in writing and in a graphic form using a burn-unit type chart. A significant number of missed fractures and retained foreign bodies were identified with these surveys.