Does the ‘Seatbelt Sign’ predict intra-abdominal injury after motor vehicle trauma in children?
Date First Published:
September 13, 2011
Last Updated:
February 15, 2012
Report by:
Landen Rentmeester, Emergency Medicine Resident (Grand Rapids Medical Education Partners/Michigan State University)
Search checked by:
James DeCou, MD, Grand Rapids Medical Education Partners/Michigan State University
Three-Part Question:
In [children involved in motor vehicle trauma] is the [seat belt sign] predictive of [significant intra-abdominal injury]?
Clinical Scenario:
A 9-year-old boy presents to the Emergency Department (ED) following a motor vehicle collision. He was a restrained rear seated passenger involved in a head on crash at approximately 45 mph. His physical examination is unremarkable, except for the presence of bruising on the lower abdomen in the distribution of his lap belt, consistent with a ‘seat belt sign,’ (SBS). The boy otherwise looks well. You wonder whether there is evidence to help you decide to discharge the patient, pursue additional imaging, or admit the child for observation/further intervention.
Search Strategy:
Ovid MEDLINE 1948 to November Week 2 2011
Embase via NHS Evidence 1980—date of searching 21 November 2011
The Cochrane Library November 2011
Embase via NHS Evidence 1980—date of searching 21 November 2011
The Cochrane Library November 2011
Search Details:
Medline:[exp abdominal injuries] AND [seat belt sign.mp]. Limit to English language and all child (0–18 years).
Embase: [exp abdominal injuries AND *SEATBELT/] OR [seat and belt and sign ti.ab.]
Cochrane: MeSH descriptor Seat Belts explode all trees.
Embase: [exp abdominal injuries AND *SEATBELT/] OR [seat and belt and sign ti.ab.]
Cochrane: MeSH descriptor Seat Belts explode all trees.
Outcome:
Fifty-one papers were identified of which three were relevant to the clinical question and of sufficient quality for inclusion
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Association between the “seat belt sign” and intra-abdominal injury in children with blunt torso trauma. Sokolove PE, Kuppermann N, Holmes JF. 2005, United States | Children 16 years of age and younger with blunt trauma at risk for intra-abdominal injury who presented to the ED following a motor vehicle collision over a two year time period.<br><br>390 children of whom 46 had SBS. | Prospective Observational Study | Relative Risk (RR) of SBS for gastrointestinal tract injury | 12.8 (5.3, 31) P=0.001 | Evaluation bias was mentioned as a weakness in the paper, as patients with abnormal physical findings, including SBS, were more likely to undergo radiographic or surgical evaluation. The sample size was small in regard to patients with seatbelt sign but no abdominal pain, limiting recommendations for clinical evaluation in this group. |
| RR For Pancreatic injury | 22.4 (2.4, 211) P=0.006 | ||||
| RR For Solid Organ injury | 0.9 (0.3, 2.4) P<1.00 | ||||
| RR For Intra-Abdominal injury | 2.9 (1.7, 5.0) P=0.001 | ||||
| Is the “Seat Belt Sign” associated with serious abdominal injuries in pediatric trauma? Chidester S, Rana A, Lowell W et al. 2009, United States | All Pediatric patients involved in an MVC, requiring trauma team activation from 2005 to 2006, divided into cohorts based on whether a seatbelt sign was documented on physical exam.<br><br>390 children of whom 46 had SBS. | Retrospective Review | Relative Risk for intra-abdominal injury | 1.7 (0.96-2.69) P=0.078 | The study is limited in that it is a retrospective, single institution study. The study was unable to obtain information whether children without SBS were restrained passengers, which may explain why children without SBS were more severely injured. There was a small number of children in the SBS cohort, limiting statistical significance of SBS as an indicator of abdominal injury |
| Sensitivity & Specificity of SBS for identifying abdominal injiury | 25% and 85% | ||||
| Predictive Indicators for bowel Injury in pediatric patients who present with a positive seat belt sign after motor vehicle collision. Paris C, Brindamour M, Ouimet A et al. 2010, Canada | Children admitted to a Canadian tertiary pediatric trauma care center with abdominal wall bruising following MVC over a 10 year time period<br><br>53 children | Retrospective Chart Review | Pulse rate>120 as predictor for Intestinal Peforation | OR=9.75 P=0.048 | The study is limited in that it is a retrospective single institution study. The study does not directly compare patients with SBS to those without SBS. 28% of patients with SBS underwent evaluation for lumbar fracture by physical exam alone. |
| Free Intra abdominal Fluids as predictor for Intestinal Peforation | OR=none P<=0.001 | ||||
| Associated Lumbar Fractures as predictor for Intestinal Peforation | OR=4.77 P=0.008 |
Author Commentary:
With the introduction of seat belts in automobiles, passenger mortality in motor vehicle collisions has significantly decreased due to changes in injury patterns. The injury pattern noted with seatbelt use has been called the ‘seat belt syndrome,’ consisting of abdominal wall bruising (known as a ‘seatbelt sign’ or SBS), lumbar spine fractures, and intra abdominal injury. Intra abdominal injury can be difficult to diagnose upon initial presentation, and outcomes improve as injuries are identified earlier. The SBS is a frequent clinical finding in children after motor vehicle collision and the studies included in this analysis seek to establish the predictive value of the SBS in paediatric patients as a clinical indicator for further diagnostic evaluation. Two of the three studies compared patients with and without SBS, using those without as controls, and the third study involved only patients with SBS, dividing these patients between those who underwent operation, and those who did not.
Bottom Line:
The seatbelt sign appears to be associated with an increased risk of intra-abdominal injuries, especially gastrointestinal and pancreatic injuries. Patients with SBS along with tachycardia, lumbar fracture, or free intra-abdominal fluid require continued close observation and may need operative intervention.
References:
- Sokolove PE, Kuppermann N, Holmes JF.. Association between the “seat belt sign” and intra-abdominal injury in children with blunt torso trauma.
- Chidester S, Rana A, Lowell W et al.. Is the “Seat Belt Sign” associated with serious abdominal injuries in pediatric trauma?
- Paris C, Brindamour M, Ouimet A et al.. Predictive Indicators for bowel Injury in pediatric patients who present with a positive seat belt sign after motor vehicle collision.