PERIPHERAL NERVE INJURY IN COMBAT CASUALTIES FROM IRAQ AND AFGHANISTAN

Abstract

Over 75% of combat casualties from Iraq and Afghanistan sustain injuries to the extremities, with 70% resulting from the effects of explosions. Damage to peripheral nerves may influence the surgical decision on limb viability in the short-term, as well as result in significant long-term disability. To date, there have been no reports of the incidence and severity of nerve injury in the current conflicts.

A prospective assessment of United Kingdom (UK) Service Personnel attending a specialist nerve injury clinic was performed. For each patient the mechanism, level and severity of injury to the nerve was assessed and associated injuries were recorded.

Fifty-six patients with 117 nerve injuries (median 2, range 1–5) were eligible for inclusion. This represents 12.9% of casualties sustaining an extremity injury. The most commonly injured nerves were the tibial (19%), common peroneal (16%) and ulnar nerves (16%). 25% (29) of nerve injuries were conduction block, 41% (48) axonotmesis and 34% (40) neurotmesis. The mechanism of injury did not affect the severity of injury sustained (explosion vs gunshot wound (GSW), p=0.53). An associated fracture was found in only 48% of nerve injuries and a vascular injury in 35%. The presence of an associated vascular injury resulted in more severe injuries (conduction vs axonotmesis and neurotmesis, p< 0.05). Nerves injured in association with a fracture, were more likely to develop axonotmesis (p< 0.05).

The incidence of peripheral nerve injury from combat wounds is higher than previously reported. This may be related to increasing numbers of casualties surviving with complex extremity wounds. In a polytrauma situation, it may be difficult to assess a discrete peripheral neurological lesion. As only 35% of nerves injured are likely to have anatomical disruption, the presence of an intact nerve at initial surgery should not preclude the possibility of an injury. Therefore, serial examinations combined with appropriate neurophysiologic examination in the post-injury period are necessary to aid diagnosis and to allow timely surgical intervention. In addition, conduction block nerve injuries can be expected to make a full recovery. As this accounts for 25% of all nerve injuries, we recommend that the presence of an insensate extremity should not be used as an indicator for assessing limb viability.