We see seat belt signs at our trauma center with some regularity. There are plenty of papers out there that detail the injuries that occur and the need for a low threshold for surgically exploring these patients. I have not been able to find specific management guidelines, and want to share some tidbits I have learned over the years. Yes, this is based on anecdotal experience, but it’s the best we have right now.
Tips for surgeons:
Common injuries involve the terminal ileum, proximal jejunum, and sigmoid colon. My observation is that location in the car is associated with the injury location, probably because of the location of the seat belt buckle. In the US, drivers buckle on the right, and I’ve seen more terminal ileum and buckethandle injuries in this group. Front seat passengers buckle on the left, and I tend to see proximal jejunum and sigmoid injuries more often in them.
Seat belt sign on physical exam requires abdominal CT for evaluation, regardless of age. The high incidence of significant injury mandates this test.
Seat belt sign plus any anomaly on CT requires evaluation in the OR. The only exception would be a patient with minimal fluid only in the pelvis with an unremarkable abdominal exam. But I would watch them like a hawk.
In patients who cannot be examined clinically (e.g. severe TBI), a rising WBC count or lactate beginning on day 2 after adequate resuscitation should prompt a trip to the OR. This is an indirect method for detecting injured bowel or mesentery.
Laparoscopy may be used in patients with equivocal findings. Excessive blood, bile tinged fluid, succus, or lots of fibrin deposits on the bowel should prompt conversion to laparotomy. Tip: place all ports distant to the seat belt mark. The soft tissues are frequently disrupted, and gas may leak into this pocket prohibiting good insufflation of the peritoneal cavity.
If in doubt, open the abdomen. It’s bad form to put in the scope, see something odd, and walk away. Remember, any abnormal finding after trauma is related to trauma until proven otherwise. It’s almost never pre-existing disease.
Ford is introducing rear seat belts with built-in airbags in its 2011 Explorer SUV. It’s a $395 option that is designed to diffuse crash impact across a wider area of the chest. This is particularly important when strapping children in the back seat.
The system uses a cold gas system, unlike the heated gases in standard airbags that can cause minor burns. Ford plans to roll it out to additional models in later model years.
The video shows how the system works in slow motion. Very “cool”!
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.
The Trauma Professional's Blog provides information on injury-related topics to trauma professionals. It is written by Michael McGonigal MD, the Director of Trauma Services at Regions Hospital in St. Paul, MN. Regions is a Level I Adult Trauma Center, and has partnered with Gillette Children's Specialty Hospital to become the first Level I Pediatric Trauma Center in the Upper Midwest.