SKULL FRACTURES AND ULTRASOUND
Written by: Saumil Patel, MD. Edited by: Jeff Greco, MD.
“Help! I’ve Fallen and I Can’t Get Up!”
How many times have you heard this in an infant patient? Probably zero times. However pediatric falls are very common and often these pediatric patients may seem well on the surface, but what lies underneath…is a skull fracture. Many tools have been implemented and used in the emergency setting such as the PECARN, but all roads ultimately lead to a CT scan depending on the patient risk. With CT, comes radiation, excessive cost, transport and depending on the age of the patient, complete intolerance of lying still (if only we could tap into pediatric energy). What if there was a way to avoid those things, do to imaging at bedside, and potentially evaluate for a fracture in mere minutes? Well, potentially, yes there is.
Ultrasound and Skull Fractures
The rise of POCUS has marked its territory in the use of ultrasound towards evaluation of skull fractures. Multiple studies over the last several years have attempted to find efficacy in the use of ultrasound in evaluation for fractures. Although studies have shown to accurately diagnose fracture with ultrasound, a negative finding does not exclude the presence of one. According to one study from Joni E. Rabiner, et al. out of 69 patients with suspected skull fractures at a mean age of 6.4 years, the prevalence of fracture was 12% and POCUS had a sensitivity of 88%, specificity of 97%. So, you must be at the edge of your seat just waiting to grab a probe, but then you realized, “How do I even do this?”
Hand Over the Gel and Probe Buddy – The Technique
Find an ultrasound with a linear array probe. Place the probe on the area of the skull at the point of maximal tenderness, hematoma or any sign of possible fracture. Now you are ready to scan. Make sure you scan in two planes. You will be looking for disruptions in the cortex. Now, you are probably thinking “Hey, these kids have sutures, how can I differentiate?” If you are unsure whether what you are seeing is a fracture or suture, you can essentially follow the cortical break you are seeing until you reach a fontanelle. Then you can continue scanning from the fontanelle to the contralateral side for comparison. If you do not see a similar pattern, chances are what you saw is a fracture. A cortical break if seen in a fracture will look ragged and have sharp margins. A suture will typically have a smoother appearance.
Fig 1: Normal cranial ultrasound in 2 orientations
Fig 2: (A and B) Ultrasound of cranial fracture in 2 dimensions. (C and D) Comparative images on CT
Fig 3: Image of the different sutures seen on ultrasound. Note that an anechoic gap is present through the entire bone.
To the Future
So you have successfully identified a skull fracture using POCUS. Your patient was not sedated, did not wait in your ER for hours to get transported to a machine, did not receive radiation. The only additional thing you need to do is clean the goop off his/her head. As PECARN is still the most used clinical decision tool for pediatric head injuries, the recommended imaging is still CT. POCUS for skull fractures still requires more research and further study before being used as a replacement for CT imaging. Unfortunately, there can be other intracranial injuries without the evidence of fracture, but there is a bright future, in ultimately decreasing costs and radiation to our pediatric population. Get going!
References
Alerhand, S. (2014, October 14). Ultrasound for Pediatric Skull Fractures. Retrieved from emDocs: http://www.emdocs.net/ultrasound-pedi-skull-fractures/
Fox, S. M. (2019, March 8). Ultrasound for Pediatric Head Injury. Retrieved from Pediatric EM Morsels: https://pedemmorsels.com/ultrasound-for-pediatric-head-injury/
Jadoga, A. (2019, August 15). Ultrasound Assessment for Skull Fractures. Retrieved from EB Medicine: https://www.ebmedicine.net/ebmblog/feature-update/ultrasound-assessment-for-skull-fractures/
Parri, N. C., J, B., Glass, C., Mannelli, F., Sforzi, I., Schiavone, R., & Ban, K. M. (2013). Ability of Emergency Ultrasonography to Detect Pediatric Skull Fractures: A Prospective, Observational Study. The Journal of Emergency Medicine, 135-141.
Rabiner, J. E., Friedman, L. M., Khine, H. A., & Tsung, J. W. (2013). Accuracy of Point-of-Care Ultrasound for Diagnosis of Skull Fractures in Children. Official Journal of the American Academy of Pediatrics.
Toyoko, O., Nuri, T., Harada, A., Kyutoku, K. S., & Ueda, K. (2019). Cranial Suture Measurement by 2-point method in Ultrasound Screening of Craniosynostosis. American Society of Plastic Surgeons International Open Access Journal.