54.10 Missile wounds

Missile wounds, which were only seen by army surgeons in the past, are now common in many of the district hospitals of the developing world. If a patient reaches you alive, you will probably be able to save him, provided his heart or his major blood vessels or his large gut have not been injured. The most important steps are a thorough wound toilet and delayed primary closure.

The higher the velocity of a missile, the greater the damage it does. A low velocity missile, as from a pistol, drills only a narrow track, with little damage around it. A high velocity missile from a modern high velocity rifle, causes an explosion in the tissues with extensive cavitation. Small entry and exit wounds may conceal gross damage inside.

Try to visualize the structures that a missile may have passed through. This is difficult because it may take a very remarkable path, as in Fig. 54-11. If there is no exit wound, look for the missile inside the patient by taking X-rays in two planes.

The wounds from standard rifle bullets are least likely to be infected, because firing will have sterilized them and they do not cause much tissue destruction. Both ’home made’, unsterile low velocity missiles, and high velocity missiles causing bursting injuries, are more likely to result in severe infected wounds. Antibiotics have the same rather uncertain role that they have in other wounds (54.1).

de Wind C M, Management of missile injuries in a peripheral hospital, Tropical Doctor 1984;14:157–159

Figure 54.11: MISSILE WOUNDS may take a curious path. The missile may be deflected by bone (A), or take a path that depends on the position of the patient at the time of the injury,as in B, and C. D, shows a hight velocity missile creating a cavity surrounded by damaged tissue and causing a partial vacuum which sucks in debris. E, and F, show some of the complex movements that can increase the damage that a missile does as it goes through a patient. A, B, and C, after Naclerio, by permission of Grune and Stratton. D, E, and F, from the Field Surgery Pocket Book with kind permission of Guy Blackburn.

MISSILE WOUNDS

See elsewhere for missile wounds of a patient’s head (63.6), and his abdomen (66.2).

Resuscitate and anaesthetize him. Leave any existing dressings on until you reach the theatre. Excise the entry and exit wounds, and remove all devitalised tissue.

If the entry and exit wounds are small and there is not much tenderness in between, it is probably a low velocity injury. You will probably be able to toilet it and save the patient’s limb. There is likely to be only a narrow track; cleaning it of all visible debris may be enough. If the track is superficial, unroof it by joining the entry and exit wounds. If it runs more deeply, you may be able to flush it through with saline.

If the exit wound is large, the patient’s limb grossly swollen, his bone much fragmented and he is severely shocked, he has probably been injured by a high velocity missile. You you may have to remove much blood clot, dead muscle, and many bone fragments. Prepare for major surgery. Occasionally, you may have to amputate his limb.

Control all bleeding, leave the wound open (except for face wounds which can be closed immediately), and cover it with gauze.

After 3 to 6 days, bring the patient back to the theatre and inspect his wound under general or local anaesthesia. If it looks clean and there are no signs of infection, close it by delayed primary suture. If if is not clean and there is dead tissue present, do a further wound toilet.

CAUTION! (1) Don’t forget tetanus prophylaxis. (2) If you are going to refer a patient, do the necessary early treatment first—reduce a fracture, drain his chest, or explore his abdomen. (3) If removing a missile is going to be more dangerous than leaving it in, leave it. There are many asymptomatic missile carriers.

DIFFICULTIES WITH MISSILE INJURIES

If a patient’s BONE HAS BEEN COMMINUTED by the missile, toilet the wound as above, and then leave it unsutured and dressed inide a cast without a window. Consider sending him home. Remove the cast at 4 to 6 weeks. You will probably find a clean healing wound filled with granulation tissue, and a fracture that is uniting clinically and radiologically as it should.

If his THORAX is involved, a thoracotomy may not be necessary, and you will probably not be able to do one anyway. Drain a haemothorax or haemopneumothorax (65.4 and 65.5). The lung is remarkably resistant to missile injuries.