high-velocity and low-velocity gunshot wounds

A 19-year-old male ranch-hand was accidently shot in the left leg while pursuing a coyote. His coworker fired, and the bullet ricocheted before striking him in the thigh.

If the patient sustained a fracture that did not require surgical stabilization, a gunshot wound from which of the following weapons likely does NOT need to be treated surgically as an open fracture, i.e., does not need to undergo operative debridement?

1. 8-mm round shot from a pistol

2. 277 hunting rifle

3. “Buckshot” from a shotgun at 12 ft

4. 22 caliber bullet from an M16

 

Discussion

The correct answer is (A). Gunshot fractures caused by low-velocity weapons do not need to be treated surgically unless the fracture itself requires operative fixation. Low-velocity weapons include most handguns (except magnums) and any weapon with a muzzle velocity <350 m/s. Hunting rifles and military rifles (such as the M16) have muzzle velocities >600 m/s and are high-velocity weapons. A shotgun, regardless of the type of shot used, is an intermediate velocity, and the level of energy imparted to the patient depends on the range from which it was shot. Close range for a shotgun is anything less than 21 ft.

Upon examination of the patient, it is noted that he has an entrance wound proximal and lateral to the superior pole of the patella and no exit wound. His radiographs show a stable fracture of the lateral femoral condyle and a retained bullet fragment within the soft tissues adjacent to the distal femur. From the history, the patient believes he was shot with a handgun.

What is the next step in management?

1. Local wound care, IV antibiotics, knee immobilizer

2. Load the knee with up to 155 cc of sterile saline

3. Surgical debridement of the wound with removal of retained bullet

4. Immediate surgical debridement with open reduction and internal fixation of the bone fragment

Discussion

The correct answer is (B). In this case, you need more information before deciding on the definitive plan of care. Since the wound was caused by a low-velocity weapon, it may not need to go to the operating room. Local wound care may be appropriate, but due to the proximity of the wound to the knee, you need to determine if there is an open joint first. If the saline load test is positive, then irrigation of the knee is the next appropriate step. The question stem states that the fracture is stable, and therefore does not need immediate open reduction and internal fixation. Also, if the bullet is retained in the muscle and not in the joint, it does not necessarily need to be removed.

Which of the following statements regarding retained bullets is true?

1. A bullet fragment in the superior patella does not need to be removed.

2. A bullet that passed through the abdomen and is located in the vertebral body of L1 should be surgically removed.

3. A bullet with a posterior entrance wound and located in the spinal canal at L3 with weak knee extension should be excised.

4. A bullet with viscous penetration before lodging in the ilium should be excised with copious irrigation.

Discussion

The correct answer is (C). Any intra-articular retained metallic fragment should be removed due to risk of plumbism. Bullets that pass through abdominal organs before going into bone, such as the spine and ilium, do not require removal if the associated fractures are stable. A 7- to 14-day course of IV antibiotics to cover intestinal bacteria is the preferred treatment unless the fractures require fixation. However, if there is a retained bullet in the spinal cord and a corresponding incomplete motor deficit, surgical excision of the fragment is indicated.

 

Objectives: Did you learn...?

 

The difference in management of high-velocity and low-velocity gunshot wounds?

 

The treatment of various gunshot injuries depending on the course of the missile or the location of the retained fragment?