Best Of: Spine Immobilization in Penetrating Trauma: More Harm Than Good?
The EMS standard of care for blunt trauma patients has been to fully immobilize the spine before transporting to an emergency department. This is such a common practice that it is frequently applied to victims of penetrating trauma prior to transport.
A recent study in the Journal of Trauma calls this practice in question, and suggests that it may increase mortality! The authors reviewed data in the National Trauma Data Bank, looking at information on penetrating trauma patients. They found that approximately 4% of these patients underwent spine immobilization.
Review of mortality statistics found that the mortality in non-immobilized (7%) doubled to 14% in the immobilized group!
The authors also found that medics would have to fail to immobilize over 1000 patients to harm one who really needed it, but to fully immobilize 66 patients who didn’t need it to contribute to 1 death.
Although this type of study can’t definitely show why immobilization in these patients is bad, it can be teased out by looking at related research. Even the relatively short delays caused by applying collars and back boards can lead to enough of a delay to definitive care in penetrating trauma patients that it could be deadly. The assumption in all of these patients is that they are bleeding to death until proven otherwise.
A number of studies have suggested that a “limited scene intervention” to prehospital care is best. The assumption is that the most effective treatment can only be delivered at a trauma center, so rapid transport with attention to airway, breathing and circulation is the best practice.
While interesting, some real-life common sense should be applied by all medics who treat these types of patients. The reality is that it is nearly impossible to destabilize the spine with a knife, so all stab victims can be transported without a thought to spine immobilization. Gunshots can damage the spine and spinal cord, so if there is any doubt that the bullet passed nearby, at least simple precautions should be taken to minimize spine movement.
Reference: Spine Immobilization in Penetrating Trauma: More Harm Than Good? Haut et al, Johns Hopkins. J Trauma 68(1): 115-121, 2010.
The Seat Belt Sign
Officially, a seat belt sign consists of contusions and abrasions on the abdomen of a restrained occupant involved in a motor vehicle crash. The seat belt syndrome takes this one step further, with injury to the abdominal organs or spine.
Seat belts save lives by reducing the number of people dying from head injury after a car crash. However, they do so by diverting energy from the head to the chest and abdomen. Overall, people who don’t wear seat belts have a 10% chance of abdominal injury. With seat belts in place, this increases to 15%. And if the person is wearing seat belts and has a seat belt sign, the risk of injury increases to 65%!
This isn’t a bad thing, however. We can fix abdominal injuries, but we can’t fix the brain; it has to heal on its own, and slowly at that.
Seat belts are associated with the Chance fracture, an uncommon fracture of the lumbar spine, usually at L1. These usually only occur with the use of lap belts without shoulder restraints, which is found less and less in cars today. These used to be located in the center of the rear seat, but most new cars offer shoulder restraints in this location now.
Chance fractures need to be assessed by a spine surgeon so that stability can be determined. If stable and there is minimal kyphosis, a brace may be appropriate for treatment. However, if the fracture is not stable or there is more than about 15 degrees of angulation, surgery will be necessary.
As seat belt use increases, seat belt signs are becoming more common. Any patient with a seat belt sign must have an abdominal CT. If any abnormal findings are noted, a surgeon must be consulted because it is very likely that operative intervention will be required.
To view a slideset about seat belt sign, click here.
Trauma 20 Years Ago: Chance Fractures
Centers that take care of blunt trauma are familiar with the spectrum on injury that is directly attributable to seat belt use. Although proper restraint significantly decreases mortality and serious head injury, seat belts can cause visceral injury, especially to small bowel.
Lap belt use has been associated with Chance fracture (flexion distraction injury to the lumbar spine) since 1982. The association between seat belts and intra-abdominal injury, especially with an obvious “seat belt sign” was first described in 1987.
Twenty years ago, orthopedic surgeons in Manitoba finally put two and two together and reported a series of 7 cases of Chance fractures. They noted that 6 of the fractures were associated with restraint use. Seat belt sign was also present in 5 of the 6 patients with fractures and three of the six had bowel injuries.
The authors noted that many provinces were mandating seatbelt use at the time, and they predicted that the number of Chance fractures, seat belt signs and hollow viscus injuries would increase. On the positive side, the number of deaths and serious head injuries would be expected to decline.
Although this was a small series, it finally cemented the unusual Chance fracture, seat belt sign, and bowel injury after motor vehicle trauma.
Reference: Pediatric Chance Fractures: Association with Intra-abdominal Injuries and Seatbelt Use. Reid et al. J Trauma 30(4) 384-91, 1990.
How Good Is The Spine Exam In Penetrating Injury?
Examination of the spine in trauma patients is typically not very helpful. We always look for stepoffs. swelling and tenderness, but the correlation with actual injury is poor. A recent paper presented at the American Medical Student Association Annual Convention showed that it actually can be helpful in victims of penetrating injury.
A prospective study of 282 patients was carried out at a Level I Trauma Center, specifically focusing on penetrating trauma. Half had gunshot wounds, and 8% sustained spinal injury with one third left with permanent disability. Stab wounds never led to a spinal cord injury. The most common patterns for cord injury in gunshot wounds was a single shot to the head or neck, or multiple shots to the torso.
The examiners looked for pain, tenderness, deformity and neurologic deficit. They found that the sensitivity was 67%, the specificity was 90%, the positive predictive value was 95% and the negative predictive value was 46%. These numbers are much better than those found during spine examination after blunt trauma. They also determined that prehospital immobilization after penetrating injury would not have helped, which I have also written about here.
The bottom line: a good spine exam in victims of penetrating trauma can accelerate definitive management prior to defining the exact details of the injury with radiographic or MRI imaging. This is particularly helpful in patients who present to non-trauma centers, where imaging or image interpretation may not be readily available.
Reference: American Medical Student Association (AMSA) 60th Annual Convention: Abstract 26: Presented March 11, 2010