Seat Belt Sign

1. See Also
   1. Adult Safety Belt
   2. Child Safety Seat
2. Signs
   1. Abdominal abrasions and Contusions associated with Seat Belt restraint
3. Precautions
   1. Seat Belts restraints are critical protection against ejection and serious Head Injury
   2. Benefits of Seat Belts far outweigh the risks of Seat Belt Syndrome
4. Pathophysiology
   1. Seat Belt Syndrome
      1. Lap belt acts as a fulcrum with flexion and other injuries (spine, viscus, vasculature) in this plane
5. Complications: Seat Belt Syndrome in Adults
   1. Aortic Injury
   2. Abdominal organ injury (Lap belt injury)
      1. Seat Belt Sign is associated with abdominal organ injury in 65% of cases
      2. Associated with mesentary bucket handle injury and Small Bowel injury
         1. Risk of bowel ischemia and delayed peritonitis
      3. Relative Risk of significant intra-Abdominal Injury: 8
      4. Obtain CT Abdomen in nearly all cases
         1. Negative CT Abdomen
            1. Consider observation for 12-24 hours (East U.S. Trauma Surgery Guidelines)
            2. Close interval follow-up may be acceptable (discuss with local Trauma surgery)
         2. Equivocal CT Abdomen (trace free fluid, bowel wall thickening or stranding)
            1. Observe for 12-24 hours with serial examinations
            2. Surgery for fever, peritoneal signs, clinically worsening
            3. May disposition home if pain resolved, tolerating fluids, stable Vital Signs
         3. Positive CT Abdomen
            1. Surgery (Laparotomy)
   3. Lumbar Fracture at L1 (Chance Fracture)
      1. Uncommon, but high risk, unstable Fracture associated with Seat Belt use without Shoulder restraint
      2. Surgery evaluation required to determine Fracture stability
   4. Blunt Neck Trauma
      1. Associated with Shoulder belt
      2. Presents with anterior neck Bruises
      3. May be associated with Laryngeal Fracture, tracheal Fracture, carotid injury
6. Complications: Seat Belt Syndrome in Children
   1. See Pediatric Blunt Abdominal Trauma
   2. See Pediatric Blunt Abdominal Trauma Decision Rule
   3. Seat Belt Sign had intraabdominal injuries in 5.7% of children without Abdominal Pain, tenderness (2% required surgery)
      1. Mahajan (2015) Acad Emerg Med 22(9): 1034-41 [PubMed]
   4. Car Restraints significantly reduce the risk of injury and death, but must be used properly
      1. Car Seats should be used up to age 4 years old (rear facing until age 2 years)
      2. Booster Seats should be used from age 4-8 years old (until height >=57 inches)
         1. Premature use of the adult Shoulder-Lap belt risks neck extension and flexion injuries
   5. Lap belt is intended to rest over the pelvic brim (anterior superior iliac spine)
      1. Younger child Pelvis can not support the Lap belt restraint
      2. Restraint may ride high over the soft tissues of the Abdomen in children
         1. Results in greater transmission of MVA forces to the spine, vessels and organs
   6. Seat Belt Syndrome associated injuries in children
      1. Lumbar Fracture or Chance Fracture (esp. L2-3)
         1. Associated with Abdominal Injury concurrently in 15% of cases
      2. Gastrointestinal Trauma (present in 11% of cases with Seat Belt Sign)
         1. Bowel perforation
         2. Bowel wall Hematoma
         3. Mesenteric tear
         4. Mesenteric vessel devascularization
         5. Solid organ injury is less well correlated but may affect Spleen, liver, Kidney or Pancreas
   7. Blunt Neck Trauma related to Shoulder belt
      1. See Blunt Neck Trauma
      2. Higher risk of neck injury if premature transition from Booster Seat to lap-Shoulder belt
7. References
   1. McClung and Ruttan (2019) Crit Dec Emerg Med 33(3): 3-11
   2. Spangler and Inaba in Herbert (2016) EM:Rap 16(5): 6-7
   3. Trauma Professional's Blog
      1. http://regionstraumapro.com/post/663723636
   4. Lutz (2004) J Pediatr Surg 39(6): 972-5 [PubMed]
   5. Borgialli (2014) Acad Emerg Med 21(11): 1240-8 [PubMed]